Sample records for adjacent forest stands

  1. Continuity in fire disturbance between riparian and adjacent sideslopes in the Douglas-fire forest series.

    Treesearch

    Richard L. Everett; Richard Schellhaas; Pete Ohlson

    2000-01-01

    Fire scar and stand cohort records were used to estimate the number and timing of fire disturbance events that impacted riparian and adjacent sideslope forests in the Douglas-fir series. Data were gathered from 49 stream segments on 24 separate streams on the east slope of the Washington Cascade Range. Upslope forests had more traceable disturbance events than riparian...

  2. Stand-level gas-exchange responses to seasonal drought in very young versus old Douglas-fir forests of the Pacific Northwest, USA

    Treesearch

    Sonia Wharton; Matt Schroeder; Ken Bible; Matthias Falk; Kyaw Tha Paw U

    2009-01-01

    This study examines how stand age affects ecosystem mass and energy exchange response to seasonal drought in three adjacent Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. The sites include two early seral (ES) stands (0 to 15 years old) and an old-growth (OG) (~450 to 500 years old) forest in the Wind River Experimental Forest,...

  3. Enhancing wildlife habitat when regenerating stands

    Treesearch

    Frank R., III Thompson

    1989-01-01

    Forest regeneration cuttings affect wildlife habitat more drastically than most forest management practices because a mature forest stand is replaced by a young sapling stand. Regeneration cuttings quickly provide habitat for many wildlife species but they also influence wildlife use of the new stand and adjacent areas throughout the rotation. Retaining snags, cavity...

  4. Characteristics of Declining Forest Stands on the Allegheny National Forest

    Treesearch

    William H. McWilliams; Robert White; Stanford L. Arner; Christopher, A. Nowak; Susan L. Stout; Susan L. Stout

    1996-01-01

    Forest stands with advanced symptoms of forest decline located on the Allegheny National Forest in northwestern Pennsylvania were studied to describe contemporary stand structure and composition, and the status of regeneration. Across all 340 stands, 12 percent of the total basal area per acre was in dead trees and 16 percent was in trees at high risk of mortality. For...

  5. Stand size, stand distribution, and rotation lengths for forest wildlife

    Treesearch

    Steven E. Backs; Russel R. Titus

    1989-01-01

    The key to managing forest wildlife is providing diverse habitats. Stand size, stand distribution, and rotation length determine how diverse habitats will be. Since the tenure of private forest owners is generally shorter than prescribed rotations, rotation recommendations serve more as guides to the amount and intensity of cutting needed to maintain desired habitat....

  6. Expansion of forest stands into tundra in the Noatak National Preserve, northwest Alaska

    USGS Publications Warehouse

    Suarez, F.; Binkley, Dan; Kaye, Margot W.; Stottlemyer, R.

    1999-01-01

    Temperatures across the northern regions of North America have been increasing for 150 years, and forests have responded to this increase. In the Noatak National Preserve in Alaska, white spruce (Picea glauca [Moench] Voss) forests reach their northern limit, occurring primarily on well-drained sites and as gallery forests along streams. Rolling plateaus of tundra separate the white spruce forests into disjunct stands. We examined patterns of tree age, tree growth, and tree encroachment into tundra ecosystems in six stands along the Agashashok River. Warming over the past 150 years appears to have increased tree growth and resulted in forest expansion into adjacent tundra ecosystems. The forest/tundra ecotone shifted by about 80 to 100 m into the tundra in the past 200 years, as evidenced by declining maximum tree age with distance towards the tundra. The decadal-scale pattern of tree establishment at the farthest extent of trees into the tundra (the tundra-forest ecotone) correlated with the detrended growth index for trees within the forests; climate conditions that led to higher tree growth appeared to foster tree establishment in the tundra. This recent forest expansion has occurred across topographic boundaries, from well-drained soils on slopes onto poorly drained, flatter areas of tundra. Further expansion of the forests may be limited by more severe wind exposure and poor drainage that make the majority of tundra less suitable for trees.

  7. Stand hazard rating for central Idaho forests

    Treesearch

    Robert Steele; Ralph E. Williams; Julie C. Weatherby; Elizabeth D. Reinhardt; James T. Hoffman; R. W. Thier

    1996-01-01

    Growing concern over sustainability of central ldaho forests has created a need to assess the health of forest stands on a relative basis. A stand hazard rating was developed as a composite of 11 individual ratings to compare the health hazards of different stands. The composite rating includes Douglas-fir beetle, mountain pine beetle, western pine beetle, spruce...

  8. Determining stocking, forest type and stand-size class from forest inventory data

    Treesearch

    Mark H. Hansen; Jerold T. Hahn

    1992-01-01

    This paper describes the procedures used by North Central Forest Experiment Station's Forest Inventory and Analysis Work Unit (NCFIA) in determining stocking, forest type, and stand-size class. The stocking procedure assigns a portion of the stocking to individual trees measured on NCFIA 10-point field plots. Stand size and forest type are determined as functions...

  9. Relating P-band AIRSAR backscatter to forest stand parameters

    NASA Technical Reports Server (NTRS)

    Wang, Yong; Melack, John M.; Davis, Frank W.; Kasischke, Eric S.; Christensen, Norman L., Jr.

    1993-01-01

    As part of research on forest ecosystems, the Jet Propulsion Laboratory (JPL) and collaborating research teams have conducted multi-season airborne synthetic aperture radar (AIRSAR) experiments in three forest ecosystems including temperate pine forest (Duke, Forest, North Carolina), boreal forest (Bonanza Creek Experimental Forest, Alaska), and northern mixed hardwood-conifer forest (Michigan Biological Station, Michigan). The major research goals were to improve understanding of the relationships between radar backscatter and phenological variables (e.g. stand density, tree size, etc.), to improve radar backscatter models of tree canopy properties, and to develop a radar-based scheme for monitoring forest phenological changes. In September 1989, AIRSAR backscatter data were acquired over the Duke Forest. As the aboveground biomass of the loblolly pine forest stands at Duke Forest increased, the SAR backscatter at C-, L-, and P-bands increased and saturated at different biomass levels for the C-band, L-band, and P-band data. We only use the P-band backscatter data and ground measurements here to study the relationships between the backscatter and stand density, the backscatter and mean trunk dbh (diameter at breast height) of trees in the stands, and the backscatter and stand basal area.

  10. 14. Charles Acey Cobb standing adjacent to the fish screen ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    14. Charles Acey Cobb standing adjacent to the fish screen he designed and installed in the Congdon Canal, facing southeast. Photo dates ca. late 1920's. - Congdon Canal, Fish Screen, Naches River, Yakima, Yakima County, WA

  11. A primer on stand and forest inventory designs

    Treesearch

    H. Gyde Lund; Charles E. Thomas

    1989-01-01

    Covers designs for the inventory of stands and forests in detail and with worked-out examples. For stands, random sampling, line transects, ricochet plot, systematic sampling, single plot, cluster, subjective sampling and complete enumeration are discussed. For forests inventory, the main categories are subjective sampling, inventories without prior stand mapping,...

  12. Outbreak of Drepanopeziza fungus in aspen forests and variation in stand susceptibility: leaf functional traits, compensatory growth and phenology.

    PubMed

    Call, Anson C; St Clair, Samuel B

    2017-09-01

    In the spring of 2015, a severe outbreak of the necrotrophic pathogen Drepanopeziza (also known as Marssonina) spread across large portions of aspen (Populus tremuloides Michx.) forests in the western United States. Among adjacent stands, some were diseased and others were not. Drepanopeziza infection in diseased aspen stands stimulated compensatory growth of second-flush leaves at the top of the canopy. These patterns of infection provided an opportunity to characterize associations of pathogen infection and leaf functional traits. Eight pairs of adjacent healthy and diseased aspen stands were identified across a forest landscape in northern Utah. Average leaf surface area, specific leaf area (SLA), photosynthesis, starch concentration and defense chemistry expression (phenolic glycosides and condensed tannins) were measured on original, first-flush leaves in the lower portion of the tree canopy of healthy and diseased stands and compensatory, second-flush leaves produced in the canopy top of diseased stands. Only first-flush leaves of diseased stands showed high levels of Drepanopeziza infection. Leaf area of second-flush leaves of diseased stands was threefold larger than all other leaf types in healthy or diseased stands. Lower canopy leaves of healthy stands had the highest SLA. Photosynthesis was lowest in infected first-flush leaves, highest in second-flush leaves of diseased stands and intermediate in leaves of healthy stands. Foliar starch concentrations were lower in leaves of diseased stands than leaves from healthy stands. Condensed tannins were greater in second-flush leaves than first-flush leaves in both healthy and diseased stands. Phenolic glycoside concentrations were lowest in infected leaves of diseased stands. Diseased stands leafed out a week earlier in the spring than healthy stands, which may have exposed their emerging leaves to rainy conditions that promote Drepanopeziza infection. Compensatory leaf regrowth of diseased stands appears to

  13. Standing dead tree resources in forests of the United States

    Treesearch

    Christopher W. Woodall; Karen L. Waddell; Christopher M. Oswalt; James E. Smith

    2013-01-01

    Given the importance of standing dead trees to numerous forest ecosystem attributes/ processes such as fuel loadings and wildlife habitat, the Forest Inventory and Analysis (FIA) Program of the Forest Service, U.S. Department of Agriculture, initiated a consistent nationwide inventory of standing dead trees in 1999. As the first cycle of annual standing dead tree...

  14. The role of stand history in assessing forest impacts

    USGS Publications Warehouse

    Dale, V.H.; Doyle, T.W.

    1987-01-01

    Air pollution, harvesting practices, and natural disturbances can affect the growth of trees and forest development. To make predictions about anthropogenic impacts on forests, we need to understand how these factors affect tree growth. In this study the effect of disturbance history on tree growth and stand structure was examined by using a computer model of forest development. The model was run under the climatic conditions of east Tennessee, USA, and the results compared to stand structure and tree growth data from a yellow poplar-white oak forest. Basal area growth and forest biomass were more accurately projected when rough approximations of the thinning and fire history typical of the measured plots were included in the simulation model. Stand history can influence tree growth rates and forest structure and should be included in any attempt to assess forest impacts.

  15. Stand age and climate drive forest carbon balance recovery

    NASA Astrophysics Data System (ADS)

    Besnard, Simon; Carvalhais, Nuno; Clevers, Jan; Herold, Martin; Jung, Martin; Reichstein, Markus

    2016-04-01

    Forests play an essential role in the terrestrial carbon (C) cycle, especially in the C exchanges between the terrestrial biosphere and the atmosphere. Ecological disturbances and forest management are drivers of forest dynamics and strongly impact the forest C budget. However, there is a lack of knowledge on the exogenous and endogenous factors driving forest C recovery. Our analysis includes 68 forest sites in different climate zones to determine the relative influence of stand age and climate conditions on the forest carbon balance recovery. In this study, we only included forest regrowth after clear-cut stand replacement (e.g. harvest, fire), and afforestation/reforestation processes. We synthesized net ecosystem production (NEP), gross primary production (GPP), ecosystem respiration (Re), the photosynthetic respiratory ratio (GPP to Re ratio), the ecosystem carbon use efficiency (CUE), that is NEP to GPP ratio, and CUEclimax, where GPP is derived from the climate conditions. We implemented a non-linear regression analysis in order to identify the best model representing the C flux patterns with stand age. Furthermore, we showed that each C flux have a non-linear relationship with stand age, annual precipitation (P) and mean annual temperature (MAT), therefore, we proposed to use non-linear transformations of the covariates for C fluxes'estimates. Non-linear stand age and climate models were, therefore, used to establish multiple linear regressions for C flux predictions and for determining the contribution of stand age and climate in forest carbon recovery. Our findings depicted that a coupled stand age-climate model explained 33% (44%, average site), 62% (76%, average site), 56% (71%, average site), 41% (59%, average site), 50% (65%, average site) and 36% (50%, average site) of the variance of annual NEP, GPP, Re, photosynthetic respiratory ratio, CUE and CUEclimax across sites, respectively. In addition, we showed that gross fluxes (e.g. GPP and Re) are

  16. Stocking, Forest Type, and Stand Size Class - The Southern Forest Inventory and Analysis Unit's Calculation of Three Important Stand Descriptors

    Treesearch

    Dennis M. May

    1990-01-01

    The procedures by which the Southern Forest Inventory and Analysis unit calculates stocking from tree data collected on inventory sample plots are described in this report. Stocking is then used to ascertain two other important stand descriptors: forest type and stand size class. Inventory data for three plots from the recently completed 1989 Tennessee survey are used...

  17. Mistletoe-induced growth reductions at the forest stand scale.

    PubMed

    Kollas, Chris; Gutsch, Martin; Hommel, Robert; Lasch-Born, Petra; Suckow, Felicitas

    2018-05-01

    The hemiparasite European mistletoe (Viscum album L.) adversely affects growth and reproduction of the host Scots pine (Pinus sylvestris L.) and in consequence may lead to tree death. Here, we aimed to estimate mistletoe-induced losses in timber yield applying the process-based forest growth model 4C. The parasite was implemented into the eco-physiological forest growth model 4C using (literature-derived) established impacts of the parasite on the tree's water and carbon cycle. The amended model was validated simulating a sample forest stand in the Berlin area (Germany) comprising trees with and without mistletoe infection. At the same forest stand, tree core measurements were taken to evaluate simulated and observed growth. A subsample of trees were harvested to quantify biomass compartments of the tree canopy and to derive a growth function of the mistletoe population. The process-based simulations of the forest stand revealed 27% reduction in basal area increment (BAI) during the last 9 years of heavy infection, which was confirmed by the measurements (29% mean growth reduction). The long-term simulations of the forest stand before and during the parasite infection showed that the amended forest growth model 4C depicts well the BAI growth pattern during >100 years and also quantifies well the mistletoe-induced growth reductions in Scots pine stands.

  18. Forest Stands Selected by Foraging Red-Cockaded Woodpeckers

    Treesearch

    Robert G. Hooper; Richard F. Harlow

    1986-01-01

    Selection of forest stands by 18 clans of foraging red-cockaded woodpeckers was studied in their year-round home ranges. The foraging use of 276 stands relative to their availability within the home ranges was compared to several stand characteristics. Selection among stands with similar characteristics was highly vairable and red-cockadeds foraged in stands with a...

  19. Stand-replacing wildfires increase nitrification for decades in southwestern ponderosa pine forests.

    PubMed

    Kurth, Valerie J; Hart, Stephen C; Ross, Christopher S; Kaye, Jason P; Fulé, Peter Z

    2014-05-01

    Stand-replacing wildfires are a novel disturbance within ponderosa pine (Pinus ponderosa) forests of the southwestern United States, and they can convert forests to grasslands or shrublands for decades. While most research shows that soil inorganic N pools and fluxes return to pre-fire levels within a few years, we wondered if vegetation conversion (ponderosa pine to bunchgrass) following stand-replacing fires might be accompanied by a long-term shift in N cycling processes. Using a 34-year stand-replacing wildfire chronosequence with paired, adjacent unburned patches, we examined the long-term dynamics of net and gross nitrogen (N) transformations. We hypothesized that N availability in burned patches would become more similar to those in unburned patches over time after fire as these areas become re-vegetated. Burned patches had higher net and gross nitrification rates than unburned patches (P < 0.01 for both), and nitrification accounted for a greater proportion of N mineralization in burned patches for both net (P < 0.01) and gross (P < 0.04) N transformation measurements. However, trends with time-after-fire were not observed for any other variables. Our findings contrast with previous work, which suggested that high nitrification rates are a short-term response to disturbance. Furthermore, high nitrification rates at our site were not simply correlated with the presence of herbaceous vegetation. Instead, we suggest that stand-replacing wildfire triggers a shift in N cycling that is maintained for at least three decades by various factors, including a shift from a woody to an herbaceous ecosystem and the presence of fire-deposited charcoal.

  20. The influece of forest gaps on some properties of humus in a managed beech forest, northern Iran

    NASA Astrophysics Data System (ADS)

    Vajari, K. A.

    2015-10-01

    The present research focuses on the effect of eight-year-old artificially created gaps on some properties of humus in managed beech-dominated stand in Hyrcanian forest of northern Iran. In this study, six-teen gaps were sampled in site and were classified into four classes (small, medium, large, and very large) with four replications for each. Humus sampling was carried out at the centre and at the cardinal points within each gap as well as in the adjacent closed stand, separately, as composite samples. The variables of organic carbon, P, K, pH, and total N were measured for each sample. It was found that the gap size had significant effect only on total N (%) and organic carbon (%) in beech stand. The amount of potassium clearly differed among three positions in beech forest. The adjacent stand had higher significantly potassium than center and edge of gaps. Different amount of potassium was detected in gap center and gap edge. Comparison of humus properties between gaps and its adjacent stand pointed to the higher amount of potassium in adjacent stand than that in gaps but there was no difference between them regarding other humus properties. According to the results, it can be concluded that there is relatively similar condition among gaps and closed adjacent stands in terms of humus properties eight years after logging in the beech stand.

  1. Examining incentives for adjacent non-industrial private forest landowners to cooperate

    Treesearch

    Melinda Vokoun; Gregory S Amacher; Jay Sullivan; Dave Wear

    2010-01-01

    Individual landowners may capture non-timber benefits from both their own forested parcels and adjacent parcels owned by different landowners. These benefits may affect incentives for landowners to cooperate in their forest management decisions. Landowner survey data is used to examine incentives to cooperate concerning joint forest management and coordination of...

  2. Soil mercury distribution in adjacent coniferous and deciduous stands highly impacted by acid rain in the Ore Mountains, Czech Republic

    USGS Publications Warehouse

    Navrátil, Tomáš; Shanley, James B.; Rohovec, Jan; Oulehle, Filip; Šimeček, Martin; Houška, Jakub; Cudlín, Pavel

    2016-01-01

    Forests play a primary role in the cycling and storage of mercury (Hg) in terrestrial ecosystems. This study aimed to assess differences in Hg cycling and storage resulting from different vegetation at two adjacent forest stands - beech and spruce. The study site Načetín in the Czech Republic's Black Triangle received high atmospheric loadings of Hg from coal combustion in the second half of the 20th century as documented by peat accumulation rates reaching 100 μg m−2 y−1. In 2004, the annual litterfall Hg flux was 22.5 μg m−2 y−1 in the beech stand and 14.5 μg m−2 y−1 in the spruce stand. Soil concentrations and pools of Hg had a strong positive relation to soil organic matter and concentrations of soil sulfur (S) and nitrogen (N). O-horizon Hg concentrations ranged from 245 to 495 μg kg−1 and were greater in the spruce stand soil, probably as a result of greater dry Hg deposition. Mineral soil Hg concentrations ranged from 51 to 163 μg kg−1 and were greater in the beech stand soil due to its greater capacity to store organic carbon (C). The Hg/C ratio increased with depth from 0.3 in the O-horizon to 3.8 μg g−1 in the C horizon of spruce soil and from 0.7 to 2.7 μg g−1 in beech soil. The Hg/C ratio was greater at all mineral soil depths in the spruce stand. The organic soil Hg pools in beech and spruce stands (6.4 and 5.7 mg m−2, respectively) were considerably lower than corresponding mineral soil Hg pools (39.1 and 25.8 mg m−2). Despite the important role of S in Hg cycling, differences in soil Hg distribution at both stands could not be attributed to differences in soil sulfur speciation.

  3. Timber resources of the Kuskokwim flood plain and adjacent upland.

    Treesearch

    Karl M. Hegg; Harold. Sieverding

    1979-01-01

    The first intensive forest inventory of the Kuskokwim River flood plains and adjacent uplands was conducted in 1967. A commercial forest area of 252.5 thousand acres (102.2 thousand hectares) was identified with a growing-stock volume of 343.0 million cubic feet (9.7 million cubic meters). A noncommercial stratum was also examined that had substantial standing volume...

  4. Simulating stand climate, phenology, and photosynthesis of a forest stand with a process-based growth model.

    PubMed

    Rötzer, Thomas; Leuchner, Michael; Nunn, Angela J

    2010-07-01

    In the face of climate change and accompanying risks, forest management in Europe is becoming increasingly important. Model simulations can help to understand the reactions and feedbacks of a changing environment on tree growth. In order to simulate forest growth based on future climate change scenarios, we tested the basic processes underlying the growth model BALANCE, simulating stand climate (air temperature, photosynthetically active radiation (PAR) and precipitation), tree phenology, and photosynthesis. A mixed stand of 53- to 60-year-old Norway spruce (Picea abies) and European beech (Fagus sylvatica) in Southern Germany was used as a reference. The results show that BALANCE is able to realistically simulate air temperature gradients in a forest stand using air temperature measurements above the canopy and PAR regimes at different heights for single trees inside the canopy. Interception as a central variable for water balance of a forest stand was also estimated. Tree phenology, i.e. bud burst and leaf coloring, could be reproduced convincingly. Simulated photosynthesis rates were in accordance with measured values for beech both in the sun and the shade crown. For spruce, however, some discrepancies in the rates were obvious, probably due to changed environmental conditions after bud break. Overall, BALANCE has shown to respond to scenario simulations of a changing environment (e.g., climate change, change of forest stand structure).

  5. Tropical forest biomass estimation from truncated stand tables.

    Treesearch

    A. J. R. Gillespie; S. Brown; A. E. Lugo

    1992-01-01

    Total aboveground forest biomass may be estimated through a variety of techniques based on commercial inventory stand and stock tables. Stand and stock tables from tropical countries commonly omit trees bellow a certain commercial limit.

  6. Variation in carbon storage and its distribution by stand age and forest type in boreal and temperate forests in northeastern China.

    PubMed

    Wei, Yawei; Li, Maihe; Chen, Hua; Lewis, Bernard J; Yu, Dapao; Zhou, Li; Zhou, Wangming; Fang, Xiangmin; Zhao, Wei; Dai, Limin

    2013-01-01

    The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and <5%, in boreal and temperate forests respectively, and thus play a minor role in total forest C storage in NE China.

  7. Variation in Carbon Storage and Its Distribution by Stand Age and Forest Type in Boreal and Temperate Forests in Northeastern China

    PubMed Central

    Wei, Yawei; Li, Maihe; Chen, Hua; Lewis, Bernard J.; Yu, Dapao; Zhou, Li; Zhou, Wangming; Fang, Xiangmin; Zhao, Wei; Dai, Limin

    2013-01-01

    The northeastern forest region of China is an important component of total temperate and boreal forests in the northern hemisphere. But how carbon (C) pool size and distribution varies among tree, understory, forest floor and soil components, and across stand ages remains unclear. To address this knowledge gap, we selected three major temperate and two major boreal forest types in northeastern (NE) China. Within both forest zones, we focused on four stand age classes (young, mid-aged, mature and over-mature). Results showed that total C storage was greater in temperate than in boreal forests, and greater in older than in younger stands. Tree biomass C was the main C component, and its contribution to the total forest C storage increased with increasing stand age. It ranged from 27.7% in young to 62.8% in over-mature stands in boreal forests and from 26.5% in young to 72.8% in over-mature stands in temperate forests. Results from both forest zones thus confirm the large biomass C storage capacity of old-growth forests. Tree biomass C was influenced by forest zone, stand age, and forest type. Soil C contribution to total forest C storage ranged from 62.5% in young to 30.1% in over-mature stands in boreal and from 70.1% in young to 26.0% in over-mature in temperate forests. Thus soil C storage is a major C pool in forests of NE China. On the other hand, understory and forest floor C jointly contained less than 13% and <5%, in boreal and temperate forests respectively, and thus play a minor role in total forest C storage in NE China. PMID:23977252

  8. Effect of stand width and adjacent habitat on breeding bird communities in bottomland hardwoods

    Treesearch

    John C. Kilgo; Robert A. Sargent

    1998-01-01

    Bottomland hardwood forests support an abundant and diverse avifauna, but area of this forest type has been reduced, and current projections indicate continued declines. The authors compared breeding bird abundance indices and species richness among bottomland hardwood stands ranging in width from 1,000 m and enclosed by forested habitat. They also...

  9. Forest stand growth dynamics in Central Europe have accelerated since 1870

    PubMed Central

    Pretzsch, Hans; Biber, Peter; Schütze, Gerhard; Uhl, Enno; Rötzer, Thomas

    2014-01-01

    Forest ecosystems have been exposed to climate change for more than 100 years, whereas the consequences on forest growth remain elusive. Based on the oldest existing experimental forest plots in Central Europe, we show that, currently, the dominant tree species Norway spruce and European beech exhibit significantly faster tree growth (+32 to 77%), stand volume growth (+10 to 30%) and standing stock accumulation (+6 to 7%) than in 1960. Stands still follow similar general allometric rules, but proceed more rapidly through usual trajectories. As forest stands develop faster, tree numbers are currently 17–20% lower than in past same-aged stands. Self-thinning lines remain constant, while growth rates increase indicating the stock of resources have not changed, while growth velocity and turnover have altered. Statistical analyses of the experimental plots, and application of an ecophysiological model, suggest that mainly the rise in temperature and extended growing seasons contribute to increased growth acceleration, particularly on fertile sites. PMID:25216297

  10. Attributes of standing dead trees in forests of the United States

    Treesearch

    Christopher W. Woodall; James E. Smith; Patrick D. Miles

    2009-01-01

    Standing dead trees in forests of the United States serve as wildlife habitat, a fuel loading component, and carbon stocks. Although standing dead trees are a vital component of forest ecosystems, information regarding this resource across the Nation is lacking. The first annual inventory of standing dead trees across the United States was initiated in 1999, resulting...

  11. Changing spatial patterns of stand-replacing fire in California conifer forests

    Treesearch

    Jens T. Stevens; Brandon M. Collins; Jay D. Miller; Malcolm P. North; Scott L. Stephens

    2017-01-01

    Stand-replacing fire has profound ecological impacts in conifer forests, yet there is continued uncertainty over how best to describe the scale of stand-replacing effects within individual fires, and how these effects are changing over time. In forests where regeneration following stand-replacing fire depends on seed dispersal from surviving trees, the size and shape...

  12. The interactive impact of forest site and stand attributes and logging technology on stand management

    Treesearch

    C.B. LeDoux; J.E. Baumgras

    1991-01-01

    The impact of selected site and stand attributes on stand management is demonstrated using actual forest model plot data and a complete systems simulation model called MANAGE. The influence of terrain on the type of logging technology required to log a stand and the resulting impact on stand management is also illustrated. The results can be used by managers and...

  13. Rating forest stands for gypsy moth defoliation

    Treesearch

    Owen W. Herrick; David A. Gansner; David A. Gansner

    1986-01-01

    The severity of future defoliation can be estimated from the percentages of basal area in oaks (Quercus), black oak (Q. velutina) and chestnut oak (a prinus), and in trees with good crowns, along with the average diameter of the stand. With information on these variables, the defoliation potential of any hardwood forest stand in an approaching gypsy moth (Lymantria...

  14. Development of a stand-scale forest biodiversity index based on the state forest inventory

    Treesearch

    Diego Van Den Meersschaut; Kris Vandekerkhove

    2000-01-01

    Ecological aspects are increasingly influencing silvicultural management. Estimating forest biodiversity has become one often major tools for evaluating management strategies. A stand-scale forest biodiversity index is developed, based on available data from the state forest inventory. The index combines aspects of forest structure, woody and herbal layer composition,...

  15. Relationships between forest cutting and understory vegetation: an overview of eastern hardwood stands

    Treesearch

    Hewlette S. Crawford

    1976-01-01

    The impacts of forest cutting upon understory vegetation were evaluated for Ozark oak-hickory and Appalachian oak-pine stands. These findings were related to similar information from other eastern forest types. Production of understory vegetation is related to stand type, stand structure, stand disturbance, and site. Stand type, structure, and site operate together to...

  16. Silvicultural guidelines for forest stands threatened by the gypsy moth

    Treesearch

    Kurt W. Gottschalk

    1993-01-01

    Ecological and silvicultural information on the interaction of gypsy moth and its host forest types is incorporated into silvicultural guidelines for minimizing the impacts of gypsy moth on forest stands threatened by the insect. Decision charts are used to match stand and insect conditions to the proper prescription that includes instructions for implementing it....

  17. Stand-Level Gas-Exchange Responses to Seasonal Drought in Very Young Versus Old Douglas-fir Forests of the Pacific Northwest, USA

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wharton, S; Schroeder, M; Bible, K

    This study examines how stand age affects ecosystem mass and energy exchange response to seasonal drought in three adjacent Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forests. The sites include two early seral stands (ES) (0-15 years old) and an old-growth (OG) ({approx} 450-500) forest in the Wind River Experiment Forest, Washington, USA. We use eddy covariance flux measurements of carbon dioxide (F{sub NEE}), latent energy ({lambda}E) and sensible heat (H) to derive evapotranspiration rate (E{sub T}), bowen ratio ({beta}), water use efficiency (WUE), canopy conductance (G{sub c}), the Priestley-Taylor coefficient ({alpha}) and a canopy decoupling factor ({Omega}). The canopy and bulkmore » parameters are examined to see how ecophysiological responses to water stress, including changes in available soil water ({theta}{sub r}) and vapor pressure deficit ({delta}e) differ among the two forest successional-stages. Despite very different rainfall patterns in 2006 and 2007, we observed distinct successional-stage relationships between E{sub T}, {alpha}, and G{sub c} to {delta}e and {theta}{sub r} during both years. The largest stand differences were (1) higher morning G{sub c} (> 10 mm s{sup -1}) at the OG forest coinciding with higher CO{sub 2} uptake (F{sub NEE} = -9 to -6 {micro}mol m{sup -2} s{sup -1}) but a strong negative response in G{sub c} to moderate {delta}e later in the day and a subsequent reduction in E{sub T}, and (2) higher E{sub T} at the ES stands because midday canopy conductance did not decrease until very low water availability levels (<30%) were reached at the end of the summer. Our results suggest that early seral stands are more likely than mature forests to experience declines in production if the summer drought becomes longer or intensifies because water conserving ecophysiological responses were only observed at the very end of the seasonal drought period in the youngest stands.« less

  18. Forest stand structure, productivity, and age mediate climatic effects on aspen decline

    USGS Publications Warehouse

    Bell, David M.; Bradford, John B.; Lauenroth, William K.

    2014-01-01

    Because forest stand structure, age, and productivity can mediate the impacts of climate on quaking aspen (Populus tremuloides) mortality, ignoring stand-scale factors limits inference on the drivers of recent sudden aspen decline. Using the proportion of aspen trees that were dead as an index of recent mortality at 841 forest inventory plots, we examined the relationship of this mortality index to forest structure and climate in the Rocky Mountains and Intermountain Western United States. We found that forest structure explained most of the patterns in mortality indices, but that variation in growing-season vapor pressure deficit and winter precipitation over the last 20 years was important. Mortality index sensitivity to precipitation was highest in forests where aspen exhibited high densities, relative basal areas, quadratic mean diameters, and productivities, whereas sensitivity to vapor pressure deficit was highest in young forest stands. These results indicate that the effects of drought on mortality may be mediated by forest stand development, competition with encroaching conifers, and physiological vulnerabilities of large trees to drought. By examining mortality index responses to both forest structure and climate, we show that forest succession cannot be ignored in studies attempting to understand the causes and consequences of sudden aspen decline.

  19. Relationships between net primary productivity and forest stand age in U.S. forests

    Treesearch

    Liming He; Jing M. Chen; Yude Pan; Richard Birdsey; Jens Kattge

    2012-01-01

    Net primary productivity (NPP) is a key flux in the terrestrial ecosystem carbon balance, as it summarizes the autotrophic input into the system. Forest NPP varies predictably with stand age, and quantitative information on the NPP-age relationship for different regions and forest types is therefore fundamentally important for forest carbon cycle modeling. We used four...

  20. New Method for Determining the Relative Stand Density of Forest Inventory Plots

    Treesearch

    Christopher W. Woodall; Patrick D. Miles

    2006-01-01

    Determining the relative density of Forest Inventory and Analysis plots is complicated by the various species and tree size combinations in the Nation?s forested ecosystems. Stand density index (SDI), although developed for use in even-aged monocultures, has been used for stand density assessment in largescale forest inventories. To improve application of SDI in uneven...

  1. Predicting temperate forest stand types using only structural profiles from discrete return airborne lidar

    NASA Astrophysics Data System (ADS)

    Fedrigo, Melissa; Newnham, Glenn J.; Coops, Nicholas C.; Culvenor, Darius S.; Bolton, Douglas K.; Nitschke, Craig R.

    2018-02-01

    Light detection and ranging (lidar) data have been increasingly used for forest classification due to its ability to penetrate the forest canopy and provide detail about the structure of the lower strata. In this study we demonstrate forest classification approaches using airborne lidar data as inputs to random forest and linear unmixing classification algorithms. Our results demonstrated that both random forest and linear unmixing models identified a distribution of rainforest and eucalypt stands that was comparable to existing ecological vegetation class (EVC) maps based primarily on manual interpretation of high resolution aerial imagery. Rainforest stands were also identified in the region that have not previously been identified in the EVC maps. The transition between stand types was better characterised by the random forest modelling approach. In contrast, the linear unmixing model placed greater emphasis on field plots selected as endmembers which may not have captured the variability in stand structure within a single stand type. The random forest model had the highest overall accuracy (84%) and Cohen's kappa coefficient (0.62). However, the classification accuracy was only marginally better than linear unmixing. The random forest model was applied to a region in the Central Highlands of south-eastern Australia to produce maps of stand type probability, including areas of transition (the 'ecotone') between rainforest and eucalypt forest. The resulting map provided a detailed delineation of forest classes, which specifically recognised the coalescing of stand types at the landscape scale. This represents a key step towards mapping the structural and spatial complexity of these ecosystems, which is important for both their management and conservation.

  2. A method of forest management for the planned introduction of intensive husbandry in virgin forest stands

    Treesearch

    B. Dolezal

    1978-01-01

    The method proposed is derived from long experience of intensive management in forest stands of Central Europe and from our proposal for management in virgin Iranian forests of the Caspian Region. The method establishes the need for systematic planning of stand conversion to insure both sustained yield and the harvesting of sufficient timber to sustain economic...

  3. Correlations among stand ages and forest strata in mixed-oak forests of southeastern Ohio

    Treesearch

    P. Charles Goebel; David M. Hix

    1997-01-01

    Many models of landscape ecosystem development, as well as of forest stand dynamics, are based upon spatial and temporal changes in the species composition and structure of various forest strata. However, few document the interrelationships among forest strata, or the response of different strata to alterations of natural disturbance regimes. To examine how...

  4. Surface forcing of non-stand-replacing fires in Siberian larch forests

    NASA Astrophysics Data System (ADS)

    Chen, Dong; Loboda, Tatiana V.

    2018-04-01

    Wildfires are the dominant disturbance agent in the Siberian larch forests. Extensive low- to mediate-intensity non-stand-replacing fires are a notable property of fire regime in these forests. Recent large scale studies of these fires have focused mostly on their impacts on carbon budget; however, their potential impacts on energy budget through post-fire albedo changes have not been considered. This study quantifies the post-fire surface forcing for Siberian larch forests that experienced non-stand-replacing fires between 2001 and 2012 using the full record of MODIS MCD43A3 albedo product and a burned area product developed specifically for the Russian forests. Despite a large variability, the mean effect of non-stand-replacing fires imposed through albedo is a negative forcing which lasts for at least 14 years. However, the magnitude of the forcing is much smaller than that imposed by stand-replacing fires, highlighting the importance of differentiating between the two fire types in the studies involving the fire impacts in the region. The results of this study also show that MODIS-based summer differenced normalized burn ratio (dNBR) provides a reliable metric for differentiating non-stand-replacing from stand-replacing fires with an overall accuracy of 88%, which is of considerable importance for future work on modeling post-fire energy budget and carbon budget in the region.

  5. Stand-level forest structure and avian habitat: Scale dependencies in predicting occurrence in a heterogeneous forest

    USGS Publications Warehouse

    Smith, K.M.; Keeton, W.S.; Donovan, T.M.; Mitchell, B.

    2008-01-01

    We explored the role of stand-level forest structure and spatial extent of forest sampling in models of avian occurrence in northern hardwood-conifer forests for two species: black-throated blue warbler (Dendroica caerulescens) and ovenbird (Seiurus aurocapillus). We estimated site occupancy from point counts at 20 sites and characterized the forest structure at these sites at three spatial extents (0.2, 3.0, and 12.0 ha). Weight of evidence was greatest for habitat models using forest stand structure at the 12.0-ha extent and diminished only slightly at the 3.0-ha extent, a scale that was slightly larger than the average territory size of both species. Habitat models characterized at the 0.2-ha extent had low support, yet are the closest in design to those used in many of the habitat studies we reviewed. These results suggest that the role of stand-level vegetation may have been underestimated in the past, which will be of interest to land managers who use habitat models to assess the suitability of habitat for species of concern. Copyright ?? 2008 by the Society of American Foresters.

  6. Forest stand losses to gypsy moth in the Poconos

    Treesearch

    David A. Gansner; Owen W. Herrick

    1978-01-01

    A Study of forest stand losses associated with the gypsy moth outbreak of the early 1970's in the Pocono Mountain Region of northeastern Pennsylvania, showed that while most of the stands incurred little or no loss, a few suffered heavy damage

  7. Canopy transpiration of pure and mixed forest stands with variable abundance of European beech

    NASA Astrophysics Data System (ADS)

    Gebauer, Tobias; Horna, Viviana; Leuschner, Christoph

    2012-06-01

    SummaryThe importance of tree species identity and diversity for biogeochemical cycles in forests is not well understood. In the past, forestry has widely converted mixed forests to pure stands while contemporary forest policy often prefers mixed stands again. However, the hydrological consequences of these changes remain unclear. We tested the hypotheses (i) that significant differences in water use per ground area exist among the tree species of temperate mixed forests and that these differences are more relevant for the amount of stand-level canopy transpiration (Ec) than putative complementarity effects of tree water use, and (ii) that the seasonal patterns of Ec in mixed stands are significantly influenced by the identity of the present tree species. We measured xylem sap flux during 2005 (average precipitation) and 2006 (relatively dry) synchronously in three nearby old-growth forest stands on similar soil differing in the abundance of European beech (pure beech stand, 3-species stand with 70% beech, 5-species stand with <10% beech). In summer 2005 with average rainfall, Ec was 50% higher in the beech-poor 5-species stand than in the two stands with moderate to high beech presence (158 vs. 97 and 101 mm yr-1); in the dry summer 2006, all stands converged toward similar Ec totals (128-139 mm yr-1). Species differences in Ec were large on a sapwood area basis, reflecting a considerable variation in hydraulic architecture and leaf conductance regulation among the co-existing species. Moreover, transpiration per crown projection area (ECA) also differed up to 5-fold among the different species in the mixed stands, probably reflecting contrasting sapwood/crown area ratios. We conclude that Ec is not principally higher in mixed forests than in pure beech stands. However, tree species-specific traits have an important influence on the height of Ec and affect its seasonal variation. Species with a relatively high ECA (notably Tilia) may exhaust soil water reserves

  8. The Development of Even-Aged Plantation Forests: An Exercise in Forest Stand Dynamics

    ERIC Educational Resources Information Center

    Wilson, E. R.; Leslie, A. D.

    2008-01-01

    In this paper we present a field-based practical exercise that allows students in forestry, ecology and natural resources to develop their understanding of forest stand dynamics. The exercise involves measurement of key tree growth parameters in four even-aged, single-species plantation stands of different age but occupying sites with similar soil…

  9. [Carbon storage of forest stands in Shandong Province estimated by forestry inventory data].

    PubMed

    Li, Shi-Mei; Yang, Chuan-Qiang; Wang, Hong-Nian; Ge, Li-Qiang

    2014-08-01

    Based on the 7th forestry inventory data of Shandong Province, this paper estimated the carbon storage and carbon density of forest stands, and analyzed their distribution characteristics according to dominant tree species, age groups and forest category using the volume-derived biomass method and average-biomass method. In 2007, the total carbon storage of the forest stands was 25. 27 Tg, of which the coniferous forests, mixed conifer broad-leaved forests, and broad-leaved forests accounted for 8.6%, 2.0% and 89.4%, respectively. The carbon storage of forest age groups followed the sequence of young forests > middle-aged forests > mature forests > near-mature forests > over-mature forests. The carbon storage of young forests and middle-aged forests accounted for 69.3% of the total carbon storage. Timber forest, non-timber product forest and protection forests accounted for 37.1%, 36.3% and 24.8% of the total carbon storage, respectively. The average carbon density of forest stands in Shandong Province was 10.59 t x hm(-2), which was lower than the national average level. This phenomenon was attributed to the imperfect structure of forest types and age groups, i. e., the notably higher percentage of timber forests and non-timber product forest and the excessively higher percentage of young forests and middle-aged forest than mature forests.

  10. Forest floor fuels in red and jack pine stands

    Treesearch

    James K. Brown

    1966-01-01

    An investigation to determine the quantity and density of forest floor fuels in red pine (Pinus resinosa Ait.) and jack pine (Pinus banksiana Lamb.) stands was conducted on National Forests in Michigan and Minnesota. The study was designed to answer three questions: How much fuel per acre exits in individual layers of the forest floor? How reliably can weight of...

  11. Responses of Isolated Wetland Herpetofauna to Upland Forest Management

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Russell, K.R.; Hanlin, H.G.; Wigley, T.B.

    2002-01-02

    Measurement of responses of herpetofauna at isolated wetlands in the Coastal Plain of South Carolina to disturbance of adjacent loblolly pine forest. Many species of isolated wetland herpetofauna in the Southeastern Coastal Plain may tolerate some disturbance in adjacent upland stands. Responses of isolated wetland herpetofauna to upland silviculture and the need for adjacent forested buffers likely depend on the specific landscape context in which the wetlands occur and composition of the resident herpetofaunal community.

  12. Stand, species, and individual traits impact transpiration in historically disturbed forests.

    NASA Astrophysics Data System (ADS)

    Blakely, B.; Rocha, A. V.; McLachlan, J. S.

    2017-12-01

    Historic logging disturbances have changed the structure and species composition of most Northern temperate forests. These changes impact the process of transpiration - which in turn impacts canopy surface temperature - but the links among structure, composition, and transpiration remain unclear. For this reason, ecosystem models typically use simplified structure and composition to simulate the impact of disturbances on forest transpiration. However, such simplifications ignore real variability among stands, species, and individual trees that may strongly influence transpiration across spatial and temporal scales. To capture this variability, we monitored transpiration in 48 individual trees of multiple species in both undisturbed (400+ yr) and historically logged (80 - 120 yr) forests. Using modern and historic forest surveys, we upscaled our observations to stand and regional scales to identify the key changes impacting transpiration. We extended these inferences by establishing a relationship between transpiration and measured surface temperature, linking disturbance-induced changes in structure and composition to local and regional climate. Despite greater potential evapotranspiration and basal area, undisturbed forest transpired less than disturbed (logged) forest. Transpiration was a strong predictor of surface temperature, and the canopy surface was warmer in undisturbed forest. Transpiration differences among disturbed and undisturbed forests resulted from (1) lesser transpiration and dampened seasonality in evergreen species (2) greater transpiration in younger individuals within a species, and (3) strong transpiration by large individuals. When transpiration was scaled to the stand or regional level in a simplified manner (e.g. a single transpiration rate for all deciduous individuals), the resulting estimates differed markedly from the original. Stand- species- and individual-level traits are therefore essential for understanding how transpiration and

  13. Post-frontier forest change adjacent to Braulio Carrillo National Park, Costa Rica

    Treesearch

    John Schelhas; G. Arturo Sanchez-Azofeifa

    2006-01-01

    Effective biodiversity conservation in national parks depends to a large extent on adjacent forest cover. While deforestation and forest fragmentation as a result of colonization and agriculture have been widespread in neotropical countries over the past few decades, in some places agricultural intensification, wage labor, and rural to urban migration are becoming the...

  14. Reconstructed old-growth forest stand structure and composition of two stands on the Olympic Peninsula, Washington state

    Treesearch

    David H. Peter; Constance A. Harrington

    2010-01-01

    We reconstructed the stand structure and composition for two western Washington old-growth forest stands harvested around 1930 (named Fresca and Rail) from field and historical data. Both old-growth stands had a codominant or dominant 250-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) overstory with a few scattered older Douglas-fir....

  15. Early forest dynamics in stand-replacing fire patches in the northern Sierra Nevada, California, USA

    Treesearch

    Brandon M. Collins; Gary B. Roller

    2013-01-01

    There is considerable concern over the occurrence of stand-replacing fire in forest types historically associated with low- to moderate-severity fire. The concern is largely over whether contemporary levels of stand-replacing fire are outside the historical range of variability, and what natural forest recovery is in these forest types following stand-replacing fire....

  16. Forest volume-to-biomass models and estimates of mass for live and standing dead trees of U.S. forests.

    Treesearch

    James E. Smith; Linda S. Heath; Jennifer C. Jenkins

    2003-01-01

    Includes methods and equations for nationally consistent estimates of tree-mass density at the stand level (Mg/ha) as predicted by growing-stock volumes reported by the USDA Forest Service for forests of the conterminous United States. Developed for use in FORCARB, a carbon budget model for U.S. forests, the equations also are useful for converting plot-, stand- and...

  17. Ecological indicators of forest degradation after forest fire and clear-cutting in the Siberian larch (Larix sibirica) stand of Mongolia

    Treesearch

    Y.D. Park; D.K. Lee; J.A. Stanturf; S.Y. Woo; D. Zoyo

    2009-01-01

    This study was conducted to investigate ecological indicators of forest degradation after forest fire and clear-cutting in the Siberian larch (Larix sibirica Ledeb.) stand of Mongolia. The species abundance and biodiversity indices were higher in burned and clear-cut stands than those of reference stand, but boreal understory species, such as Vaccinium vitis-idaea,...

  18. A 3D stand generator for central Appalachian hardwood forests

    Treesearch

    Jingxin Wang; Yaoxiang Li; Gary W. Miller

    2002-01-01

    A 3-dimensional (3D) stand generator was developed for central Appalachian hardwood forests. It was designed for a harvesting simulator to examine the interactions of stand, harvest, and machine. The Component Object Model (COM) was used to design and implement the program. Input to the generator includes species composition, stand density, and spatial pattern. Output...

  19. Ectomycorrhizal Community Structure and Soil Characteristics of Mature Lodgepole Pine (Pinus Contorta) and Adjacent Stands of Old Growth Mixed Conifer in Yellowstone National Park, Wyoming USA

    NASA Technical Reports Server (NTRS)

    Douglas, Robert B.; Parker, V. Thomas; Cullings, Kenneth W.; Sun, Sidney (Technical Monitor)

    2003-01-01

    Forest development patterns following disturbance are known to influence the physical and chemical attributes of soils at different points in time. Changes in soil resources are thought to have a corresponding effect on ectomycorrhizal (ECM) community structure. We used molecular methods to compare below-ground ECM species richness, composition, and abundance between adjacent stands of homogenous lodgepole pine and old growth mixed conifer in Yellowstone National Park (YNP). In each stand-type we collected soil cores to both identify mycorrhizae and assess soil chemistry. Although no statistical difference was observed in the mean number of ECM root tips per core between stand types, the total number of species identified (85 versus 35) and the mean number of species per core (8.8 +/- 0.6 versus 2.5 +/- 0.3) were significantly higher in lodgepole pine. Differences between the actual and estimated species richness levels indicated that these forest types support a high number of ECM species and that undersampling was severe. Species compositions were widely disparate between stands where only four species were shared out of a total of 116. Soil analysis also revealed that mixed conifer was significantly lower in pH, but higher in organic matter, potassium, phosphorus, and ammonium when compared to lodgepole pine stands. Species richness per core was correlated with these chemical data, however, analysis of covariance indicated that stand type was the only statistically significant factor in the observed difference in species richness. Our data suggest that ECM fungal richness increases as homogenous lodgepole pine stands grow and mature, but declines after Engelmann spruce and subalpine fir colonize. Despite difficulties linking species composition with soil chemistry, there are a variety of physical and chemical factors that could be influencing ECM community structure. Future field experiments are necessary to test some of the mechanisms potentially operating

  20. The Perfect Fire? Aging Stands in the Alaskan Boreal Forest Encounter Global Warming

    NASA Astrophysics Data System (ADS)

    Mann, D.; Rupp, S.; Duffy, P.

    2008-12-01

    The ecological responses of the boreal forest to climate change have global significance because of the large amount of carbon stored in its soils and biomass. Fire, mostly ignited by lightning, is the keystone disturbance agent in this forest. It triggers cycles of forest succession in its wake, and burning is the main avenue for carbon release back to the atmosphere. We studied the interactions between climate, fires, forest succession, and the age distributions of forest stands in a 60-million hectare region of Interior Alaska over the past 150 years. First we developed a statistical model relating climate to area burned over the period of record (1950-2005). Next we combined this model with climate reconstructions to extend the estimates of area burned back to A.D. 1860. We checked the resultant fire history against stand-age data from 5000 living trees sampled in the study region. Then we fed the history of area burned into a computer model that simulates forest succession on real landscapes. Results show striking changes in the means and variances of stand ages over the last 150 years in response to interactions between climate change and the successional dynamics of the boreal forest. Average stand age increased steadily between 1880 and 1940 and has fluctuated at high levels since then, indicating a historically unusual abundance of flammable stands. This accumulation of old stands has created the potential for unusually large fires. Some support for this conclusion comes from the unprecedented large sizes of the areas burned in 2004 and 2005. Further support comes when we add to the analysis the forecasts made by global climate models for Alaska over the next twenty years. Bracketing estimates for climate warming and precipitation change suggest that warmer, drier summers combined with aging forest stands will cause a series of unusually large fires, the like of which have not occurred in the region for >150 years. We infer that the enhanced burning of the

  1. Stand and cohort structures of old-growth Pinus resinosa-dominated forests of northern Minnesota, USA

    Treesearch

    Shawn Fraver; Brian J. Palik

    2012-01-01

    The wide range of stand and age-cohort structures in these old-growth P. resinosa stands depicts pre-settlement forests more complex than those of the single-cohort, post-stand-replacing-fire model that has guided regional forest management. Within-stand patchiness of cohort age structures implies disturbances operating at scales smaller than...

  2. Spatial impact assessment of conifer stands in the Hoosier National Forest

    Treesearch

    Richard Thurau; Craig Wayson; Dale Weigel; Jeff Ehman

    2011-01-01

    Forest management decisions on Federal lands must be administered at many spatial and temporal scales. Forest condition, size class, and cover type at the stand level determine how silvicultural practices today will impact management area and overall forest goals in the future. The Hoosier National Forest (HNF) Land Resource Management Plan lists eight goals for...

  3. Forest Stand Segmentation Using Airborne LIDAR Data and Very High Resolution Multispectral Imagery

    NASA Astrophysics Data System (ADS)

    Dechesne, Clément; Mallet, Clément; Le Bris, Arnaud; Gouet, Valérie; Hervieu, Alexandre

    2016-06-01

    Forest stands are the basic units for forest inventory and mapping. Stands are large forested areas (e.g., ≥ 2 ha) of homogeneous tree species composition. The accurate delineation of forest stands is usually performed by visual analysis of human operators on very high resolution (VHR) optical images. This work is highly time consuming and should be automated for scalability purposes. In this paper, a method based on the fusion of airborne laser scanning data (or lidar) and very high resolution multispectral imagery for automatic forest stand delineation and forest land-cover database update is proposed. The multispectral images give access to the tree species whereas 3D lidar point clouds provide geometric information on the trees. Therefore, multi-modal features are computed, both at pixel and object levels. The objects are individual trees extracted from lidar data. A supervised classification is performed at the object level on the computed features in order to coarsely discriminate the existing tree species in the area of interest. The analysis at tree level is particularly relevant since it significantly improves the tree species classification. A probability map is generated through the tree species classification and inserted with the pixel-based features map in an energetical framework. The proposed energy is then minimized using a standard graph-cut method (namely QPBO with α-expansion) in order to produce a segmentation map with a controlled level of details. Comparison with an existing forest land cover database shows that our method provides satisfactory results both in terms of stand labelling and delineation (matching ranges between 94% and 99%).

  4. Scaling Hydrologic Processes in Boreal Forest Stands: New Eco-hydrological Perspectives or Deja vu?

    NASA Astrophysics Data System (ADS)

    Silins, U.; Lieffers, V. J.; Landhausser, S. M.; Mendoza, C. A.; Devito, K. J.; Petrone, R. M.; Gan, T. Y.

    2006-12-01

    The leaf area of forest canopies is both main attribute of stands controlling water balance through transpiration and interception, and "engine" driving stand growth, stand dynamics, and forest succession. While transpiration and interception dynamics are classic themes in forest hydrology, we present results from our eco-hydrological research on boreal trees to highlight how more recent eco-physiological insights into species specific controls over water use and leaf area such as hydraulic architecture, cavitation, sapwood-leaf area relationships, and root system controls over water uptake are providing new insights into integrated atmospheric-autecological controls over these hydrologic processes. These results are discussed in the context of newer eco-hydrological frameworks which may serve to aid in exploring how forest disturbance and subsequent trajectories of hydrologic recovery are likely to affect both forest growth dynamics and hydrology of forested landscapes in response to forest management, severe forest pest epidemics such as the Mountain Pine Beetle epidemic in Western Canada, and climate change.

  5. Patterns of covariance between forest stand and canopy structure in the Pacific Northwest.

    Treesearch

    Michael A. Lefsky; Andrew T. Hudak; Warren B. Cohen; S.A. Acker

    2005-01-01

    In the past decade, LIDAR (light detection and ranging) has emerged as a powerful tool for remotely sensing forest canopy and stand structure, including the estimation of aboveground biomass and carbon storage. Numerous papers have documented the use of LIDAR measurements to predict important aspects of forest stand structure, including aboveground biomass. Other...

  6. Object-oriented classification of forest structure from light detection and ranging data for stand mapping

    Treesearch

    Alicia A. Sullivan; Robert J. McGaughey; Hans-Erik Andersen; Peter Schiess

    2009-01-01

    Stand delineation is an important step in the process of establishing a forest inventory and provides the spatial framework for many forest management decisions. Many methods for extracting forest structure characteristics for stand delineation and other purposes have been researched in the past, primarily focusing on high-resolution imagery and satellite data. High-...

  7. The long-term hydrological effect of forest stands on the stability of slopes

    NASA Astrophysics Data System (ADS)

    Bogaard, T. A.; Meng, W.; van Beek, L. P. H.

    2012-04-01

    Forest is widely known to improve slope stability as a result of mechanical and hydrological effects. While the mechanics underlying the stabilizing process of root reinforcement are well understood and quantified, the influence of forest on the occurrence of critical hydrological conditions in terms of suction or pore pressure remains uncertain. Due to seasonal and inter-annual fluctuations, the stabilizing influence of evaporation and transpiration is difficult to isolate from the overall noise of the hydrological signal. More long-term effects of forest stands on soil development are highly variable and thus difficult to observe and quantify. Often these effects are ambivalent, having potentially a stabilizing or destabilizing influence on a slope under particular conditions (e.g., more structured soils leading to both rapid infiltration and drainage). Consequently, it can be postulated that forests will hydrologically influence the magnitude-frequency distribution of landsliding, not only at the stand level but also on a regional scale through the groundwater system. The overall aim of this research is to understand and quantify the stabilizing hydrological effect of forests on potentially unstable slopes. To this end, we focus on the changes in the magnitude-frequency distribution of landsliding that arise as a result of variations in evapotranspiration losses over the life cycle of stands. Temporal variations in evapotranspiration comprise first of all the interception that can account for an important amount of evaporation from a forest, and that changes with seasonal and annual variations in the interception capacity of the canopy and forest floor. Transpiration also represents an important loss that varies over the various growth stages of a forest stand. Based on a literature review of water consumption by tree species and water balance studies of forested catchments we defined the potential transpiration for different growth stages. This information we

  8. Long-term monitoring of diversity and structure of two stands of an Atlantic Tropical Forest.

    PubMed

    Diniz, Écio Souza; Carvalho, Warley Augusto Caldas; Santos, Rubens Manoel; Gastauer, Markus; Garcia, Paulo Oswaldo; Fontes, Marco Aurélio Leite; Coelho, Polyanne Aparecida; Moreira, Aline Martins; Menino, Gisele Cristina Oliveira; Oliveira-Filho, Ary Teixeira

    2017-01-01

    This study aimed to report the long-term monitoring of diversity and structure of the tree community in a protected semideciduous Atlantic Forest in the South of Minas Gerais State, Southeast Brazil. The study was conducted in two stands (B and C), each with 26 and 38 10 m x 30 m plots. Censuses of stand B were conducted in 2000, 2005 and 2011, and stand C in 2001, 2006 and 2011. In both stands, the most abundant and important species for biomass accumulation over the inventories were trees larger than 20 cm of diameter, which characterize advanced successional stage within the forest. The two surveyed stands within the studied forest presented differences in structure, diversity and species richness over the time.

  9. Predicting forested catchment evapotranspiration and streamflow from stand sapwood area and Aridity Index

    NASA Astrophysics Data System (ADS)

    Lane, Patrick

    2016-04-01

    Estimating the water balance of ungauged catchments has been the subject of decades of research. An extension of the fundamental problem of estimating the hydrology is then understanding how do changes in catchment attributes affect the water balance component? This is a particular issue in forest hydrology where vegetation exerts such a strong influence on evapotranspiration (ET), and consequent streamflow (Q). Given the primacy of trees in the water balance, and the potential for change to species and density through logging, fire, pests and diseases and drought, methods that directly relate ET/Q to vegetation structure, species, and stand density are very powerful. Plot studies on tree water use routinely use sapwood area (SA) to calculate transpiration and upscale to the stand/catchment scale. Recent work in south eastern Australian forests have found stand-wide SA to be linearly correlated (R2 = 0.89) with long term mean annual loss (P-Q), and hence, long term mean annual catchment streamflow. Robust relationships can be built between basal area (BA), tree density and stand SA. BA and density are common forest inventory measurements. Until now, no research has related the fundamental stand attribute of SA to streamflow. The data sets include catchments that have been thinned and with varying age classes. Thus far these analyses have been for energy limited systems in wetter forest types. SA has proven to be a more robust biometric than leaf area index which varies seasonally. That long term ET/Q is correlated with vegetation conforms to the Budyko framework. Use of a downscaled (20 m) Aridity Index (AI) has shown distinct correlations with stand SA, and therefore T. Structural patterns at a the hillslope scale not only correlate with SA and T, but also with interception (I) and forest floor evaporation (Es). These correlations between AI and I and Es have given R2 > 0.8. The result of these studies suggest an ability to estimate mean annual ET fluxes at sub

  10. Canopy gap characteristics of an old-growth and an adjacent second-growth beech-maple stand in north-central Ohio

    Treesearch

    David M. Hix; P. Charles Goebel; Heather L. Whitman

    2011-01-01

    The increased importance of integrating concepts of natural disturbance regimes into forest management, as well as the need to manage for complex forest structures, requires an understanding of how forest stands develop following natural disturbances. One of the primary natural disturbance types occurring in beech-maple ecosystems of the Central Hardwood Forest is...

  11. Application of Lidar remote sensing to the estimation of forest canopy and stand structure

    NASA Astrophysics Data System (ADS)

    Lefsky, Michael Andrew

    A new remote sensing instrument, SLICER (Scanning Lidar Imager of Canopies by Echo Recovery), has been applied to the problem of remote sensing the canopy and stand structure of two groups of deciduous forests, Tulip Poplar-Oak stands in the vicinity of Annapolis, MD. and bottomland hardwood stands near Williamston, NC. The ability of the SLICER instrument to remotely sense the vertical distribution of canopy structure (Canopy Height Profile), bulk canopy transmittance, and several indices of canopy height has been successfully validated using twelve stands with coincident field and SLICER estimates of canopy structure. Principal components analysis has been applied to canopy height profiles from both field sites, and three significant factors were identified, each closely related to the amount of foliage in a recognizable layer of the forest, either understory, midstory, or overstory. The distribution of canopy structure to these layers is significantly correlated with the size and number of stems supporting them. The same layered structure was shown to apply to both field and SLICER remotely sensed canopy height profiles, and to apply to SLICER remotely sensed canopy profiles from both the bottomland hardwood stands in the coastal plain of North Carolina, and to mesic Tulip-Poplars stands in the upland coastal plain of Maryland. Linear regressions have demonstrated that canopy and stand structure are correlated to both a statistically significant and useful degree. Stand age and stem density is more highly correlated to stand height, while stand basal area and aboveground biomass are more closely related to a new measure of canopy structure, the quadratic mean canopy height. A geometric model of canopy structure has been shown to explain the differing relationships between canopy structure and stand basal area for stands of Eastern Deciduous Forest and Douglas Fir Forest.

  12. Forest inventory and management-based visual preference models of southern pine stands

    Treesearch

    Victor A. Rudis; James H. Gramann; Edward J. Ruddell; Joanne M. Westphal

    1988-01-01

    Statistical models explaining students' ratings of photographs of within stand forest scenes were constructed for 99 forest inventory plots in east Texas pine and oak-pine forest types. Models with parameters that are sensitive to visual preference yet compatible with forest management and timber inventories are presented. The models suggest that the density of...

  13. Breeding bird assemblages of hurricane-created gaps and adjacent closed canopy forest in the Southern Appalachians

    Treesearch

    Cathryn H. Greenberg; J. Drew Lanham

    2001-01-01

    We studied breeding bird assemblages in forest gaps created in 1995 by Hurricane Opal at the Bent Creek Experimental Forest in Asheville, NC. We hypothesized that forest gaps and adjacent closed-canopy forest would differ in bird density, richness, diversity, and relative abundances of some species. To test this hypothesis we censused breeding bird assemblages for 2...

  14. Simulating historical disturbance regimes and stand structures in old-forest ponderosa pine/Douglas-fir forests

    Treesearch

    Mike Hillis; Vick Applegate; Steve Slaughter; Michael G. Harrington; Helen Smith

    2001-01-01

    Forest Service land managers, with the collaborative assistance from research, applied a disturbance based restoration strategy to rehabilitate a greatly-altered, high risk Northern Rocky Mountain old-forest ponderosa pine-Douglas-fir stand. Age-class structure and fire history for the site have been documented in two research papers (Arno and others 1995, 1997)....

  15. Long-term monitoring of diversity and structure of two stands of an Atlantic Tropical Forest

    PubMed Central

    Carvalho, Warley Augusto Caldas; Santos, Rubens Manoel; Gastauer, Markus; Garcia, Paulo Oswaldo; Fontes, Marco Aurélio Leite; Coelho, Polyanne Aparecida; Moreira, Aline Martins; Menino, Gisele Cristina Oliveira; Oliveira-Filho, Ary Teixeira

    2017-01-01

    Abstract Background This study aimed to report the long-term monitoring of diversity and structure of the tree community in a protected semideciduous Atlantic Forest in the South of Minas Gerais State, Southeast Brazil. The study was conducted in two stands (B and C), each with 26 and 38 10 m x 30 m plots. Censuses of stand B were conducted in 2000, 2005 and 2011, and stand C in 2001, 2006 and 2011. In both stands, the most abundant and important species for biomass accumulation over the inventories were trees larger than 20 cm of diameter, which characterize advanced successional stage within the forest. New information The two surveyed stands within the studied forest presented differences in structure, diversity and species richness over the time. PMID:28848371

  16. Stand characteristics of 65-year-old planted and naturally regenerated stands near Sequim, Washington. Forest Service research paper

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Miller, R.E.; Anderson, H.W.

    1995-04-01

    Tree numbers, height, and volume were determined in six 63- to 66-year-old plantations of coast Douglas-fir (Pseudotsunga menziesii) (Mirb.) Franco var. menziesii in northwest Washington. These stands resulted from the first extensive plantings of this species in the Pacific Northwest. Data from 0.25-acre plots in these plantations were compared to those from matched plots in adjacent, naturally regenerated stands with the same history of logging, wildfire, and absence of further siviculture after regeneration. Planting resulted in well-stocked Douglas-fir stands with volunteers of other tree species. Natural seeding resulted in similarly stocked stands of western hemlock (Tsunga heterophylla) (Raf.) (Sarg.) withmore » Douglas-fir in the dominant crown class.« less

  17. Forest stand structure of the northern spotted owl's foraging habitat.

    Treesearch

    Malcolm P. North; Jerry F. Franklin; Andrew B. Carey; Eric D. Forsman; Tom Hamer

    1999-01-01

    Although the spotted owl's close association with old growth has been extensively studied, it more difficult to identify and quantify the abundance of particular stand structures associated with preferred owl foraging sites. Old-growth forests have a suite of characteristics that distinguish them from younger forests but which also make it difficult to isolate...

  18. Reintroducing fire in regenerated dry forests following stand-replacing wildfire.

    Treesearch

    David W. Peterson; Paul F. Hessburg; Brion Salter; Kevin M. James; Matthew C. Dahlgreen; John A. Barnes

    2007-01-01

    Prescribed fire use may be effective for increasing fire resilience in young coniferous forests by reducing surface fuels, modifying overstory stand structure, and promoting development of large trees of fire resistant species. Questions remain, however, about when and how to reintroduce fire in regenerated forests, and to what end. We studied the effects of spring...

  19. Estimating Mixed Broadleaves Forest Stand Volume Using Dsm Extracted from Digital Aerial Images

    NASA Astrophysics Data System (ADS)

    Sohrabi, H.

    2012-07-01

    In mixed old growth broadleaves of Hyrcanian forests, it is difficult to estimate stand volume at plot level by remotely sensed data while LiDar data is absent. In this paper, a new approach has been proposed and tested for estimating stand forest volume. The approach is based on this idea that forest volume can be estimated by variation of trees height at plots. In the other word, the more the height variation in plot, the more the stand volume would be expected. For testing this idea, 120 circular 0.1 ha sample plots with systematic random design has been collected in Tonekaon forest located in Hyrcanian zone. Digital surface model (DSM) measure the height values of the first surface on the ground including terrain features, trees, building etc, which provides a topographic model of the earth's surface. The DSMs have been extracted automatically from aerial UltraCamD images so that ground pixel size for extracted DSM varied from 1 to 10 m size by 1m span. DSMs were checked manually for probable errors. Corresponded to ground samples, standard deviation and range of DSM pixels have been calculated. For modeling, non-linear regression method was used. The results showed that standard deviation of plot pixels with 5 m resolution was the most appropriate data for modeling. Relative bias and RMSE of estimation was 5.8 and 49.8 percent, respectively. Comparing to other approaches for estimating stand volume based on passive remote sensing data in mixed broadleaves forests, these results are more encouraging. One big problem in this method occurs when trees canopy cover is totally closed. In this situation, the standard deviation of height is low while stand volume is high. In future studies, applying forest stratification could be studied.

  20. Polychlorinated biphenyls and polybrominated diphenylethers in soils from planted forests and adjacent natural forests on a tropical island.

    PubMed

    Liu, Xin; Wang, Shuai; Jiang, Yishan; Sun, Yingtao; Li, Jun; Zhang, Gan

    2017-08-01

    Transformation from natural forests to planted forests in tropical regions is an expanding global phenomenon causing major modifications of land cover and soil properties, e.g. soil organic carbon (SOC). This study investigated accumulations of POPs in soils under eucalyptus and rubber forests as compared with adjacent natural forests on Hainan Island, China. Results showed that due to the greater forest filter effect and the higher SOC, the natural forest have accumulated larger amounts of POPs in the top 20 cm soil. Based on correlation and air-soil equilibrium analysis, we highlighted the importance of SOC in the distribution of POPs. It is assumed that the elevated mobility of POPs in the planted forests was caused by greater loss of SOC and extensive leaching in the soil profile. This suggests that a better understanding of global POPs fate should take into consideration the role of planted forests. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. [A comparative study on soil fauna in native secondary evergreen broad-leaved forest and Chinese fir plantation forests in subtropics].

    PubMed

    Yan, Shaokui; Wang, Silong; Hu, Yalin; Gao, Hong; Zhang, Xiuyong

    2004-10-01

    In this study, we investigated the response of soil animal communities to the replacement of native secondary forest by Chinese fir plantation forest and successive rotation of Chinese fir in subtropics. Three adjacent forest stands, i.e., native secondary evergreen broad-leaved forest stand (control) and Chinese fir plantation stands of first (20 yr) and second (20 yr) rotations were selected for the comparison of soil fauna. All animals were extracted from the floor litter and 0-15 cm soil layer of the stands in Summer, 2003 by using Tullgren method, wet funnel method and hand-sorting method. Compared to two Chinese fir plantation forests, the native secondary evergreen broad-leaved forest had a higher abundance and a higher taxonomic diversity of animals in soil and litter, but there were no significant differences in the biomass and productivity of soil fauna between all study stands. The abundance or diversity did not differ significantly between the first rotation and second rotation stands, too. The results supported that vegetation cover might be one of the main forces driving the development of soil animal communities, and the effect of successive rotation of Chinese fir on the development of soil fauna was a slow-running process.

  2. Secondary forest succession following reproduction cutting on the Upper Coastal Plain of southeastern Arkansas, USA

    Treesearch

    Michael D. Cain; Michael G. Shelton

    2001-01-01

    To contribute to an understanding of forest management on secondary forest succession, we conducted vegetation surveys in a chronosequence of pine stands ranging in age from 1 to 59 years. Adjacent areas were compared at 1, 7, 12, and 17 years following two reproduction cutting methods (clearcuts or pine seed-tree cuts); a 59-year-old pine stand that...

  3. Spatial and thematic assessment of object-based forest stand delineation using an OFA-matrix

    NASA Astrophysics Data System (ADS)

    Hernando, A.; Tiede, D.; Albrecht, F.; Lang, S.

    2012-10-01

    The delineation and classification of forest stands is a crucial aspect of forest management. Object-based image analysis (OBIA) can be used to produce detailed maps of forest stands from either orthophotos or very high resolution satellite imagery. However, measures are then required for evaluating and quantifying both the spatial and thematic accuracy of the OBIA output. In this paper we present an approach for delineating forest stands and a new Object Fate Analysis (OFA) matrix for accuracy assessment. A two-level object-based orthophoto analysis was first carried out to delineate stands on the Dehesa Boyal public land in central Spain (Avila Province). Two structural features were first created for use in class modelling, enabling good differentiation between stands: a relational tree cover cluster feature, and an arithmetic ratio shadow/tree feature. We then extended the OFA comparison approach with an OFA-matrix to enable concurrent validation of thematic and spatial accuracies. Its diagonal shows the proportion of spatial and thematic coincidence between a reference data and the corresponding classification. New parameters for Spatial Thematic Loyalty (STL), Spatial Thematic Loyalty Overall (STLOVERALL) and Maximal Interfering Object (MIO) are introduced to summarise the OFA-matrix accuracy assessment. A stands map generated by OBIA (classification data) was compared with a map of the same area produced from photo interpretation and field data (reference data). In our example the OFA-matrix results indicate good spatial and thematic accuracies (>65%) for all stand classes except for the shrub stands (31.8%), and a good STLOVERALL (69.8%). The OFA-matrix has therefore been shown to be a valid tool for OBIA accuracy assessment.

  4. A stand-replacing fire history in upper montane forests of the southern Rocky Mountains

    USGS Publications Warehouse

    Margolis, E.Q.; Swetnam, T.W.; Allen, Craig D.

    2007-01-01

    Dendroecological techniques were applied to reconstruct stand-replacing fire history in upper montane forests in northern New Mexico and southern Colorado. Fourteen stand-replacing fires were dated to 8 unique fire years (1842–1901) using four lines of evidence at each of 12 sites within the upper Rio Grande Basin. The four lines of evidence were (i) quaking aspen (Populus tremuloides Michx.) inner-ring dates, (ii) fire-killed conifer bark-ring dates, (iii) tree-ring width changes or other morphological indicators of injury, and (iv) fire scars. The annual precision of dating allowed the identification of synchronous stand-replacing fire years among the sites, and co-occurrence with regional surface fire events previously reconstructed from a network of fire scar collections in lower elevation pine forests across the southwestern United States. Nearly all of the synchronous stand-replacing and surface fire years coincided with severe droughts, because climate variability created regional conditions where stand-replacing fires and surface fires burned across ecosystems. Reconstructed stand-replacing fires that predate substantial Anglo-American settlement in this region provide direct evidence that stand-replacing fires were a feature of high-elevation forests before extensive and intensive land-use practices (e.g., logging, railroad, and mining) began in the late 19th century.

  5. Forest stand structure and pattern of old-growth western hemlock/Douglas-fir and mixed-conifer forests

    Treesearch

    Malcolm North; Jiquan Chen; Brian Oakley; Bo Song; Mark Rudnicki; Andrew Gray; Jim Innes

    2004-01-01

    With fire suppression, many western forests are expected to have fewer gaps and higher stem density of shade-tolerant species as light competition becomes a more significant influence on stand pattern and composition. We compared species composition, structure, spatial pattern, and environmental factors such as light and soil moisture between two old-growth forests:...

  6. Wind in the forests of southeast Alaska and guides for reducing damage.

    Treesearch

    A.S. Harris

    1999-01-01

    Alaska based on the literature and the author's experience. Storm winds resulting in damage to forest stands are described, and some ecological and management considerations of wind that are of concern to forest managers are reviewed. The author made a general reconnaissance of forest conditions on Prince of Wales Island and adjacent islands based on forest-type...

  7. Stand density guides for predicting growth of forest tress of southwest Idaho

    Treesearch

    Douglas D. Basford; John Sloan; Joy Roberts

    2010-01-01

    This paper presents a method for estimating stand growth from stand density and average diameter in stands of pure and mixed species in Southwest Idaho. The methods are adapted from a model developed for Douglas-fir, ponderosa pine, and lodgepole pine on the Salmon National Forest. Growth data were derived from ponderosa pine increment cores taken from sample plots on...

  8. Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America.

    PubMed

    Stevens, Jens T; Safford, Hugh D; North, Malcolm P; Fried, Jeremy S; Gray, Andrew N; Brown, Peter M; Dolanc, Christopher R; Dobrowski, Solomon Z; Falk, Donald A; Farris, Calvin A; Franklin, Jerry F; Fulé, Peter Z; Hagmann, R Keala; Knapp, Eric E; Miller, Jay D; Smith, Douglas F; Swetnam, Thomas W; Taylor, Alan H

    Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the "stand age" variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1) the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2) recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical "mixed-severity" fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data.

  9. Average Stand Age from Forest Inventory Plots Does Not Describe Historical Fire Regimes in Ponderosa Pine and Mixed-Conifer Forests of Western North America

    PubMed Central

    Stevens, Jens T.; Safford, Hugh D.; North, Malcolm P.; Fried, Jeremy S.; Gray, Andrew N.; Brown, Peter M.; Dolanc, Christopher R.; Dobrowski, Solomon Z.; Falk, Donald A.; Farris, Calvin A.; Franklin, Jerry F.; Fulé, Peter Z.; Hagmann, R. Keala; Knapp, Eric E.; Miller, Jay D.; Smith, Douglas F.; Swetnam, Thomas W.; Taylor, Alan H.

    2016-01-01

    Quantifying historical fire regimes provides important information for managing contemporary forests. Historical fire frequency and severity can be estimated using several methods; each method has strengths and weaknesses and presents challenges for interpretation and verification. Recent efforts to quantify the timing of historical high-severity fire events in forests of western North America have assumed that the “stand age” variable from the US Forest Service Forest Inventory and Analysis (FIA) program reflects the timing of historical high-severity (i.e. stand-replacing) fire in ponderosa pine and mixed-conifer forests. To test this assumption, we re-analyze the dataset used in a previous analysis, and compare information from fire history records with information from co-located FIA plots. We demonstrate that 1) the FIA stand age variable does not reflect the large range of individual tree ages in the FIA plots: older trees comprised more than 10% of pre-stand age basal area in 58% of plots analyzed and more than 30% of pre-stand age basal area in 32% of plots, and 2) recruitment events are not necessarily related to high-severity fire occurrence. Because the FIA stand age variable is estimated from a sample of tree ages within the tree size class containing a plurality of canopy trees in the plot, it does not necessarily include the oldest trees, especially in uneven-aged stands. Thus, the FIA stand age variable does not indicate whether the trees in the predominant size class established in response to severe fire, or established during the absence of fire. FIA stand age was not designed to measure the time since a stand-replacing disturbance. Quantification of historical “mixed-severity” fire regimes must be explicit about the spatial scale of high-severity fire effects, which is not possible using FIA stand age data. PMID:27196621

  10. Small mammal habitat associations in poletimber and sawtimber stands of four forest cover types

    Treesearch

    Richard M. DeGraaf; Dana P. Snyder; Barbara J. Hill

    1991-01-01

    Small mammal distribution was examined in poletimber and sawtimber stands of four forest cover types in northern New England: northern hardwoods, red maple, balsam fir, and red spruce-balsam fir. During 1980 and 1981, eight stands on the White Mountain National Forest, NH, were sampled with four trap types (three sizes of snap traps and one pit-fall) for 16 000 trap-...

  11. Stand dynamics of mixed red alder-conifer forests of southeast Alaska.

    Treesearch

    Robert L. Deal; Paul E. Hennon; Ewa H. Orlikowska; David V. D' Amore

    2004-01-01

    Stand structure and dynamics were evaluated in mixed red alder (Alnus rubra Bong.) - conifer forests of southeast Alaska. We assessed stand development, tree density, total basal area, diameter distribution of live and dead trees, height distribution of live trees, and mean diameter of all and largest conifers in 40-year-old red alder - conifer...

  12. An experimental test of the causes of forest growth decline with stand age.

    Treesearch

    Michael G. Ryan; Dan Binkley; James H. Fownes; Christian Giardina; Randy S. Senock

    2004-01-01

    The decline in aboveground wood production after canopy closure in even-aged forest stands is a common pattern in forests, but clear evidence for the mechanism causing the decline is lacking. The problem is fundamental to forest biology, commercial forestry (the decline sets the rotation age), and to carbon storage in forests. We tested three hypotheses...

  13. Detection of forest stand-level spatial structure in ectomycorrhizal fungal communities

    Treesearch

    Erik A. Lilleskov; Thomas D. Bruns; Thomas R. Horton; D. Lee Taylor; Paul Grogan

    2004-01-01

    Ectomycorrhizal fungal (EMF) communities are highly diverse at the stand level. To begin to understand what might lead to such diversity, and to improve sampling designs, we investigated the spatial structure of these communities. We used EMF community data from a number of studies carried out in seven mature and one recently fire-initiated forest stand. We applied...

  14. An unsupervised two-stage clustering approach for forest structure classification based on X-band InSAR data - A case study in complex temperate forest stands

    NASA Astrophysics Data System (ADS)

    Abdullahi, Sahra; Schardt, Mathias; Pretzsch, Hans

    2017-05-01

    Forest structure at stand level plays a key role for sustainable forest management, since the biodiversity, productivity, growth and stability of the forest can be positively influenced by managing its structural diversity. In contrast to field-based measurements, remote sensing techniques offer a cost-efficient opportunity to collect area-wide information about forest stand structure with high spatial and temporal resolution. Especially Interferometric Synthetic Aperture Radar (InSAR), which facilitates worldwide acquisition of 3d information independent from weather conditions and illumination, is convenient to capture forest stand structure. This study purposes an unsupervised two-stage clustering approach for forest structure classification based on height information derived from interferometric X-band SAR data which was performed in complex temperate forest stands of Traunstein forest (South Germany). In particular, a four dimensional input data set composed of first-order height statistics was non-linearly projected on a two-dimensional Self-Organizing Map, spatially ordered according to similarity (based on the Euclidean distance) in the first stage and classified using the k-means algorithm in the second stage. The study demonstrated that X-band InSAR data exhibits considerable capabilities for forest structure classification. Moreover, the unsupervised classification approach achieved meaningful and reasonable results by means of comparison to aerial imagery and LiDAR data.

  15. Quantifying climate-growth relationships at the stand level in a mature mixed-species conifer forest.

    PubMed

    Teets, Aaron; Fraver, Shawn; Weiskittel, Aaron R; Hollinger, David Y

    2018-03-11

    A range of environmental factors regulate tree growth; however, climate is generally thought to most strongly influence year-to-year variability in growth. Numerous dendrochronological (tree-ring) studies have identified climate factors that influence year-to-year variability in growth for given tree species and location. However, traditional dendrochronology methods have limitations that prevent them from adequately assessing stand-level (as opposed to species-level) growth. We argue that stand-level growth analyses provide a more meaningful assessment of forest response to climate fluctuations, as well as the management options that may be employed to sustain forest productivity. Working in a mature, mixed-species stand at the Howland Research Forest of central Maine, USA, we used two alternatives to traditional dendrochronological analyses by (1) selecting trees for coring using a stratified (by size and species), random sampling method that ensures a representative sample of the stand, and (2) converting ring widths to biomass increments, which once summed, produced a representation of stand-level growth, while maintaining species identities or canopy position if needed. We then tested the relative influence of seasonal climate variables on year-to-year variability in the biomass increment using generalized least squares regression, while accounting for temporal autocorrelation. Our results indicate that stand-level growth responded most strongly to previous summer and current spring climate variables, resulting from a combination of individualistic climate responses occurring at the species- and canopy-position level. Our climate models were better fit to stand-level biomass increment than to species-level or canopy-position summaries. The relative growth responses (i.e., percent change) predicted from the most influential climate variables indicate stand-level growth varies less from to year-to-year than species-level or canopy-position growth responses. By

  16. Spillover from adjacent crop and forest habitats shapes carabid beetle assemblages in fragmented semi-natural grasslands.

    PubMed

    Schneider, Gudrun; Krauss, Jochen; Boetzl, Fabian A; Fritze, Michael-Andreas; Steffan-Dewenter, Ingolf

    2016-12-01

    Semi-natural grasslands in Europe are insect biodiversity hotspots and important source habitats delivering ecosystem services to adjacent agricultural land by species spillover. However, this spillover might also occur in the opposite direction, affecting the diversity of semi-natural grasslands. This opposite spillover has got little attention in scientific literature even though generalist species penetrating into the grasslands can affect local biotic interactions, community composition and the conservation value of grassland habitats. In this study, we examined spillover effects from two different adjacent habitat types on carabid beetle assemblages in 20 semi-natural calcareous grasslands. The grasslands were either adjacent to a cereal crop field or to a coniferous forest. We found distinct differences in carabid beetle assemblages in calcareous grasslands depending on adjacent habitat type. Species richness and activity density were higher, but the evenness was lower in calcareous grasslands adjacent to crop fields compared with calcareous grasslands adjacent to coniferous forests. Further, we found a strong spillover of carabid beetles from adjacent crop fields after crop harvest, which may result in transiently increased predation pressure and resource competition in calcareous grasslands. Our results highlight that species composition, diversity and presumably ecosystem functions within semi-natural habitats are affected by the type and management of surrounding habitats. This needs to be considered by nature conservation measures, which aim to protect the unique insect communities of semi-natural European grasslands.

  17. Estimating structural attributes of Douglas-fir/western hemlock forest stands from Landsat and SPOT imagery

    NASA Technical Reports Server (NTRS)

    Cohen, Warren B.; Spies, Thomas A.

    1992-01-01

    Relationships between spectral and texture variables derived from SPOT HRV 10 m panchromatic and Landsat TM 30 m multispectral data and 16 forest stand structural attributes is evaluated to determine the utility of satellite data for analysis of hemlock forests west of the Cascade Mountains crest in Oregon and Washington, USA. Texture of the HRV data was found to be strongly related to many of the stand attributes evaluated, whereas TM texture was weakly related to all attributes. Data analysis based on regression models indicates that both TM and HRV imagery should yield equally accurate estimates of forest age class and stand structure. It is concluded that the satellite data are a valuable source for estimation of the standard deviation of tree sizes, mean size and density of trees in the upper canopy layers, a structural complexity index, and stand age.

  18. Semantic Segmentation of Forest Stands of Pure Species as a Global Optimization Problem

    NASA Astrophysics Data System (ADS)

    Dechesne, C.; Mallet, C.; Le Bris, A.; Gouet-Brunet, V.

    2017-05-01

    Forest stand delineation is a fundamental task for forest management purposes, that is still mainly manually performed through visual inspection of geospatial (very) high spatial resolution images. Stand detection has been barely addressed in the literature which has mainly focused, in forested environments, on individual tree extraction and tree species classification. From a methodological point of view, stand detection can be considered as a semantic segmentation problem. It offers two advantages. First, one can retrieve the dominant tree species per segment. Secondly, one can benefit from existing low-level tree species label maps from the literature as a basis for high-level object extraction. Thus, the semantic segmentation issue becomes a regularization issue in a weakly structured environment and can be formulated in an energetical framework. This papers aims at investigating which regularization strategies of the literature are the most adapted to delineate and classify forest stands of pure species. Both airborne lidar point clouds and multispectral very high spatial resolution images are integrated for that purpose. The local methods (such as filtering and probabilistic relaxation) are not adapted for such problem since the increase of the classification accuracy is below 5%. The global methods, based on an energy model, tend to be more efficient with an accuracy gain up to 15%. The segmentation results using such models have an accuracy ranging from 96% to 99%.

  19. Red-Cockaded Woodpecker male/female foraging differences in young forest stands

    Treesearch

    Kathleen E. Franzreb

    2010-01-01

    The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to pine (Pinusspp.) forests of the southeastern United States. I examined Red-cockaded Woodpecker foraging behavior to learn if there were male/female differences at the Savannah River Site, South Carolina. The study was conducted in largely young forest stands (,50 years of age) in...

  20. Contrasting rainfall generated debris flows from adjacent watersheds at Forest Falls, southern California, USA

    USGS Publications Warehouse

    Morton, D.M.; Alvarez, R.M.; Ruppert, K.R.; Goforth, B.

    2008-01-01

    Debris flows are widespread and common in many steeply sloping areas of southern California. The San Bernardino Mountains community of Forest Falls is probably subject to the most frequently documented debris flows in southern California. Debris flows at Forest Falls are generated during short-duration high-intensity rains that mobilize surface material. Except for debris flows on two consecutive days in November 1965, all the documented historic debris flows have occurred during high-intensity summer rainfall, locally referred to as 'monsoon' or 'cloudburst' rains. Velocities of the moving debris range from about 5??km/h to about 90??km/h. Velocity of a moving flow appears to be essentially a function of the water content of the flow. Low velocity debris flows are characterized by steep snouts that, when stopped, have only small amounts of water draining from the flow. In marked contrast are high-velocity debris flows whose deposits more resemble fluvial deposits. In the Forest Falls area two adjacent drainage basins, Snow Creek and Rattlesnake Creek, have considerably different histories of debris flows. Snow Creek basin, with an area about three times as large as Rattlesnake Creek basin, has a well developed debris flow channel with broad levees. Most of the debris flows in Snow Creek have greater water content and attain higher velocities than those of Rattlesnake Creek. Most debris flows are in relative equilibrium with the geometry of the channel morphology. Exceptionally high-velocity flows, however, overshoot the channel walls at particularly tight channel curves. After overshooting the channel, the flows degrade the adjacent levee surface and remove trees and structures in the immediate path, before spreading out with decreasing velocity. As the velocity decreases the clasts in the debris flows pulverize the up-slope side of the trees and often imbed clasts in them. Debris flows in Rattlesnake Creek are relatively slow moving and commonly stop in the

  1. Mammal caching of oak acorns in a red pine and a mixed oak stand

    Treesearch

    E.R. Thorn; W.M. Tzilkowski

    1991-01-01

    Small mammal caching of oak (Quercus spp.) acorns in adjacent red pine (Pinus resinosa) and mixed-oak stands was investigated at The Penn State Experimental Forest, Huntingdon Co., Pennsylvania. Gray squirrels (Sciurus carolinensis) and mice (Peromyscus spp.) were the most common acorn-caching...

  2. Object-based semi-automatic approach for forest structure characterization using lidar data in heterogeneous Pinus sylvestris stands

    Treesearch

    C. Pascual; A. Garcia-Abril; L.G. Garcia-Montero; S. Martin-Fernandez; W.B. Cohen

    2008-01-01

    In this paper, we present a two-stage approach for characterizing the structure of Pinus sylvestris L. stands in forests of central Spain. The first stage was to delimit forest stands using eCognition and a digital canopy height model (DCHM) derived from lidar data. The polygons were then clustered into forest structure types based on the DCHM data...

  3. Species Composition of Down Dead and Standing Live Trees: Implications for Forest Inventory Analysis

    Treesearch

    Christopher W. Woodall; Linda Nagel

    2005-01-01

    The assessment of species composition in most forest inventory analysis relies solely on standing live tree information characterized by current forest type. With the implementation of the third phase of the U.S. Department of Agriculture Forest Service's Forest Inventory and Analysis program, the species composition of down dead trees, otherwise termed coarse...

  4. Modelling Variable Fire Severity in Boreal Forests: Effects of Fire Intensity and Stand Structure.

    PubMed

    Miquelajauregui, Yosune; Cumming, Steven G; Gauthier, Sylvie

    2016-01-01

    It is becoming clear that fires in boreal forests are not uniformly stand-replacing. On the contrary, marked variation in fire severity, measured as tree mortality, has been found both within and among individual fires. It is important to understand the conditions under which this variation can arise. We integrated forest sample plot data, tree allometries and historical forest fire records within a diameter class-structured model of 1.0 ha patches of mono-specific black spruce and jack pine stands in northern Québec, Canada. The model accounts for crown fire initiation and vertical spread into the canopy. It uses empirical relations between fire intensity, scorch height, the percent of crown scorched and tree mortality to simulate fire severity, specifically the percent reduction in patch basal area due to fire-caused mortality. A random forest and a regression tree analysis of a large random sample of simulated fires were used to test for an effect of fireline intensity, stand structure, species composition and pyrogeographic regions on resultant severity. Severity increased with intensity and was lower for jack pine stands. The proportion of simulated fires that burned at high severity (e.g. >75% reduction in patch basal area) was 0.80 for black spruce and 0.11 for jack pine. We identified thresholds in intensity below which there was a marked sensitivity of simulated fire severity to stand structure, and to interactions between intensity and structure. We found no evidence for a residual effect of pyrogeographic region on simulated severity, after the effects of stand structure and species composition were accounted for. The model presented here was able to produce variation in fire severity under a range of fire intensity conditions. This suggests that variation in stand structure is one of the factors causing the observed variation in boreal fire severity.

  5. Modelling Variable Fire Severity in Boreal Forests: Effects of Fire Intensity and Stand Structure

    PubMed Central

    Miquelajauregui, Yosune; Cumming, Steven G.; Gauthier, Sylvie

    2016-01-01

    It is becoming clear that fires in boreal forests are not uniformly stand-replacing. On the contrary, marked variation in fire severity, measured as tree mortality, has been found both within and among individual fires. It is important to understand the conditions under which this variation can arise. We integrated forest sample plot data, tree allometries and historical forest fire records within a diameter class-structured model of 1.0 ha patches of mono-specific black spruce and jack pine stands in northern Québec, Canada. The model accounts for crown fire initiation and vertical spread into the canopy. It uses empirical relations between fire intensity, scorch height, the percent of crown scorched and tree mortality to simulate fire severity, specifically the percent reduction in patch basal area due to fire-caused mortality. A random forest and a regression tree analysis of a large random sample of simulated fires were used to test for an effect of fireline intensity, stand structure, species composition and pyrogeographic regions on resultant severity. Severity increased with intensity and was lower for jack pine stands. The proportion of simulated fires that burned at high severity (e.g. >75% reduction in patch basal area) was 0.80 for black spruce and 0.11 for jack pine. We identified thresholds in intensity below which there was a marked sensitivity of simulated fire severity to stand structure, and to interactions between intensity and structure. We found no evidence for a residual effect of pyrogeographic region on simulated severity, after the effects of stand structure and species composition were accounted for. The model presented here was able to produce variation in fire severity under a range of fire intensity conditions. This suggests that variation in stand structure is one of the factors causing the observed variation in boreal fire severity. PMID:26919456

  6. Functional groups show distinct differences in nitrogen cycling during early stand development: implications for forest management

    Treesearch

    Doug P. Aubrey; David R. Coyle; Mark D. Coleman

    2012-01-01

    Background and aims Nutrient acquisition of forest stands is controlled by soil resource availability and belowground production, but tree species are rarely compared in this regard. Here, we examine ecological and management implications of nitrogen (N) dynamics during early forest stand development in productive commercial tree species with narrow (Populus...

  7. Formulating a stand-growth model for mathematical programming problems in Appalachian forests

    Treesearch

    Gary W. Miller; Jay Sullivan

    1993-01-01

    Some growth and yield simulators applicable to central hardwood forests can be formulated for use in mathematical programming models that are designed to optimize multi-stand, multi-resource management problems. Once in the required format, growth equations serve as model constraints, defining the dynamics of stand development brought about by harvesting decisions. In...

  8. Monitoring stand structure in mature coastal Douglas-fir forests: effect of plot size.

    Treesearch

    Andrew Gray

    2003-01-01

    National and regional interest in the distribution and trends of forest habitat structure and diversity have placed demands on forest inventories for accurate stand-level data. a primary need in the coastal Pacific Northwest of the United States is information on the extent and rate of development of mature forest structure. The objective of this study was to evaluate...

  9. Fuel management strategies in 60-year-old douglas-fir/ponderosa pine stands in the Squamish Forest district, British Columbia

    Treesearch

    Robert W. Gray; Bruce A. Blackwell

    2008-01-01

    The restoration of dry forest ecosystems in the Squamish Forest District in the past has focused on treating stands with no prior history of selective harvest and containing a large population of remnant historical stand structure. Many 60 to 90 year old stands that date...

  10. Occurrence of termites (Isoptera) on living and standing dead trees in a tropical dry forest in Mexico.

    PubMed

    Calderón-Cortés, Nancy; Escalera-Vázquez, Luis H; Oyama, Ken

    2018-01-01

    Termites play a key role as ecosystem engineers in numerous ecological processes though their role in the dynamics of wood degradation in tropical dry forests, particularly at the level of the crown canopy, has been little studied. In this study, we analysed the occurrence of termites in the forest canopy by evaluating the density and proportion of living and standing dead trees associated with termites in deciduous and riparian habitats of the tropical dry forest in Chamela, Mexico. The results indicated that 60-98% of standing dead trees and 23-59% of living trees in Chamela were associated with termites. In particular, we found that the density of standing dead trees was higher in deciduous forests (0.057-0.066 trees/m 2 ) than in riparian forests (0.022 and 0.027 trees/m 2 ), even though the proportion of trees was not significantly different among habitats. Additionally, we found a higher density of trees associated with termites in trees of smaller size classes (0.01-0.09 trees/m 2 ) than in larger class sizes (0-0.02 trees/m 2 ). Interestingly, 72% of variation in the density of trees associated with termites is explained by the density of standing dead trees. Overall, these results indicate that standing dead tree availability might be the main factor regulating termite populations in Chamela forest and suggest that termites could play a key role in the decomposition of above-ground dead wood, mediating the incorporation of suspended and standing dead wood into the soil.

  11. Occurrence of termites (Isoptera) on living and standing dead trees in a tropical dry forest in Mexico

    PubMed Central

    Escalera-Vázquez, Luis H.; Oyama, Ken

    2018-01-01

    Termites play a key role as ecosystem engineers in numerous ecological processes though their role in the dynamics of wood degradation in tropical dry forests, particularly at the level of the crown canopy, has been little studied. In this study, we analysed the occurrence of termites in the forest canopy by evaluating the density and proportion of living and standing dead trees associated with termites in deciduous and riparian habitats of the tropical dry forest in Chamela, Mexico. The results indicated that 60–98% of standing dead trees and 23–59% of living trees in Chamela were associated with termites. In particular, we found that the density of standing dead trees was higher in deciduous forests (0.057–0.066 trees/m2) than in riparian forests (0.022 and 0.027 trees/m2), even though the proportion of trees was not significantly different among habitats. Additionally, we found a higher density of trees associated with termites in trees of smaller size classes (0.01–0.09 trees/m2) than in larger class sizes (0–0.02 trees/m2). Interestingly, 72% of variation in the density of trees associated with termites is explained by the density of standing dead trees. Overall, these results indicate that standing dead tree availability might be the main factor regulating termite populations in Chamela forest and suggest that termites could play a key role in the decomposition of above-ground dead wood, mediating the incorporation of suspended and standing dead wood into the soil. PMID:29785342

  12. Stand structure and local distribution of Phytophthora ramorum in Oregon forests

    Treesearch

    E. Peterson; M. Botts; E. Hansen

    2009-01-01

    The Phytophthora ramorum eradication program in effect in Oregon has allowed for the rapid detection of new infection foci, typically before they develop within each stand and expand into adjacent sites. Yet despite gallant efforts, new locations that previously harbored no apparent infection have been identified each year since the original...

  13. Mapping of past stand-level forest disturbances and estimation of time since disturbance using simulated spaceborne LiDAR data

    NASA Astrophysics Data System (ADS)

    Sanchez Lopez, N.; Hudak, A. T.; Boschetti, L.

    2017-12-01

    Explicit information on the location, the size or the time since disturbance (TSD) at the forest stand level complements field inventories, improves the monitoring of forest attributes and the estimation of biomass and carbon stocks. Even-aged stands display homogenous structural parameters that have often been used as a proxy of stand age. Consequently, performing object-oriented analysis on Light Detection and Ranging (LiDAR) data has potential to detect historical stand-replacing disturbances. Recent research has shown good results in the delineation of forest stands as well as in the prediction of disturbance occurrence and TSD using airborne LiDAR data. Nevertheless, the use of airborne LiDAR for systematic monitoring of forest stands is limited by the sporadic availability of data and its high cost compared to satellite instruments. NASA's forthcoming Global Ecosystem Dynamics Investigations (GEDI) mission will provide systematically data on the vertical structure of the vegetation, but its use presents some challenges compared to the common discrete-return airborne LiDAR. GEDI will be a waveform instrument, hence the summary metrics will be different to those obtained with airborne LiDAR, and the sampling configuration could limit the utility of the data, especially on heterogeneous landscapes. The potential use of GEDI data for forest characterization at the stand level would therefore depend on the predictive power of the GEDI footprint metrics, and on the density of point samples relative to forest stand size (i.e. the number of observation/footprints per stand).In this study, we assess the performance of simulated GEDI-derived metrics for stand characterization and estimation of TSD, and the point density needed to adequately identify forest stands, which translates - due to the fixed sampling configuration - into the minimum temporal interval needed to collect a sufficient number of points. The study area was located in the Clear Creek, Selway River

  14. Snow accumulation under various forest stand densities at Tenderfoot Creek Experimental Forest, Montana, USA

    Treesearch

    Chadwick A. Moore; Ward W. McCaughey

    1997-01-01

    Snow accumulation in forested watersheds is controlled by climate, elevation, topographic factors and vegetation structure. Conifers affect snow accumulation principally by intercepting snow with the canopy which may later be sublimated. Various tree, stand, species and canopy densities of a subalpine fir habitat (ALBANASC) in central Montana were studied to determine...

  15. Stand density, stand structure, and species composition in transition oak stands of northwestern Pennsylvania

    Treesearch

    S.L. Stout

    1991-01-01

    Transition stands, those containing species associated with both the northern hardwood and oak-hickory forest types, are important to forest diversity in northwestern Pennsylvania. These stands have high value for a variety of forest uses, including timber production, wildlife habitat, and aesthetics. Diameter distributions are characteristically stratified by species...

  16. Relating Demographic Characteristics of a Small Mammal to Remotely Sensed Forest-Stand Condition

    PubMed Central

    Lada, Hania; Thomson, James R.; Cunningham, Shaun C.; Mac Nally, Ralph

    2014-01-01

    Many ecological systems around the world are changing rapidly in response to direct (land-use change) and indirect (climate change) human actions. We need tools to assess dynamically, and over appropriate management scales, condition of ecosystems and their responses to potential mitigation of pressures. Using a validated model, we determined whether stand condition of floodplain forests is related to densities of a small mammal (a carnivorous marsupial, Antechinus flavipes) in 60 000 ha of extant river red gum (Eucalyptus camaldulensis) forests in south-eastern Australia in 2004, 2005 and 2011. Stand condition was assessed remotely using models built from ground assessments of stand condition and satellite-derived reflectance. Other covariates, such as volumes of fallen timber, distances to floods, rainfall and life stages were included in the model. Trapping of animals was conducted at 272 plots (0.25 ha) across the region. Densities of second-year females (i.e. females that had survived to a second breeding year) and of second-year females with suckled teats (i.e. inferred to have been successful mothers) were higher in stands with the highest condition. There was no evidence of a relationship with stand condition for males or all females. These outcomes show that remotely-sensed estimates of stand condition (here floodplain forests) are relatable to some demographic characteristics of a small mammal species, and may provide useful information about the capacity of ecosystems to support animal populations. Over-regulation of large, lowland rivers has led to declines in many facets of floodplain function. If management of water resources continues as it has in recent decades, then our results suggest that there will be further deterioration in stand condition and a decreased capacity for female yellow-footed antechinuses to breed multiple times. PMID:24621967

  17. Aspen Increase Soil Moisture, Nutrients, Organic Matter and Respiration in Rocky Mountain Forest Communities

    PubMed Central

    Buck, Joshua R.; St. Clair, Samuel B.

    2012-01-01

    Development and change in forest communities are strongly influenced by plant-soil interactions. The primary objective of this paper was to identify how forest soil characteristics vary along gradients of forest community composition in aspen-conifer forests to better understand the relationship between forest vegetation characteristics and soil processes. The study was conducted on the Fishlake National Forest, Utah, USA. Soil measurements were collected in adjacent forest stands that were characterized as aspen dominated, mixed, conifer dominated or open meadow, which includes the range of vegetation conditions that exist in seral aspen forests. Soil chemistry, moisture content, respiration, and temperature were measured. There was a consistent trend in which aspen stands demonstrated higher mean soil nutrient concentrations than mixed and conifer dominated stands and meadows. Specifically, total N, NO3 and NH4 were nearly two-fold higher in soil underneath aspen dominated stands. Soil moisture was significantly higher in aspen stands and meadows in early summer but converged to similar levels as those found in mixed and conifer dominated stands in late summer. Soil respiration was significantly higher in aspen stands than conifer stands or meadows throughout the summer. These results suggest that changes in disturbance regimes or climate scenarios that favor conifer expansion or loss of aspen will decrease soil resource availability, which is likely to have important feedbacks on plant community development. PMID:23285012

  18. Stand structural diversity rather than species diversity enhances aboveground carbon storage in secondary subtropical forests in Eastern China

    NASA Astrophysics Data System (ADS)

    Ali, Arshad; Yan, En-Rong; Chen, Han Y. H.; Chang, Scott X.; Zhao, Yan-Tao; Yang, Xiao-Dong; Xu, Ming-Shan

    2016-08-01

    Stand structural diversity, typically characterized by variances in tree diameter at breast height (DBH) and total height, plays a critical role in influencing aboveground carbon (C) storage. However, few studies have considered the multivariate relationships of aboveground C storage with stand age, stand structural diversity, and species diversity in natural forests. In this study, aboveground C storage, stand age, tree species, DBH and height diversity indices, were determined across 80 subtropical forest plots in Eastern China. We employed structural equation modelling (SEM) to test for the direct and indirect effects of stand structural diversity, species diversity, and stand age on aboveground C storage. The three final SEMs with different directions for the path between species diversity and stand structural diversity had a similar goodness of fit to the data. They accounted for 82 % of the variation in aboveground C storage, 55-59 % of the variation in stand structural diversity, and 0.1 to 9 % of the variation in species diversity. Stand age demonstrated strong positive total effects, including a positive direct effect (β = 0.41), and a positive indirect effect via stand structural diversity (β = 0.41) on aboveground C storage. Stand structural diversity had a positive direct effect on aboveground C storage (β = 0.56), whereas there was little total effect of species diversity as it had a negative direct association with, but had a positive indirect effect, via stand structural diversity, on aboveground C storage. The negligible total effect of species diversity on aboveground C storage in the forests under study may have been attributable to competitive exclusion with high aboveground biomass, or a historical logging preference for productive species. Our analyses suggested that stand structural diversity was a major determinant for variations in aboveground C storage in the secondary subtropical forests in Eastern China. Hence, maintaining tree DBH and

  19. Turbulence considerations for comparing ecosystem exchange over old-growth and clear-cut stands for limited fetch and complex canopy flow conditions

    Treesearch

    Sonia Wharton; Matt Schroeder; Kyaw Tha Paw U; Matthias Falk; Ken Bible

    2009-01-01

    Carbon dioxide (CO2), water vapor, and energy fluxes were measured using eddy covariance (EC) methodology over three adjacent evergreen forests in southern Washington State to identify stand-level age-effects on ecosystem exchange. The sites represent Douglas-fir forest ecosystems at two contrasting successional stages: old-growth (OG) and early...

  20. Longer-term effects of selective thinning on microarthropod communities in a late-successional coniferous forest.

    Treesearch

    Robert W. Peck; Christine G. Niwa

    2005-01-01

    Microarthropod densities within late-successional coniferous forests thinned 16-41 yr before sampling were compared with adjacent unthinned stands to identify longer term effects of thinning on this community. Soil and forest floor layers were sampled separately on eight paired sites. Within the forest floor oribatid, mesostigmatid, and to a marginal extent,...

  1. Stand compositional dynamics in a mature Illinois Ozarks forest: implications for management

    Treesearch

    John W. Groninger; Trevor B. Ozier; Charles M. Ruffner

    2003-01-01

    The Ozark Hills region of southern Illinois is characterized by the severe topography typical of the Ozark Plateau, but is overlain by loess deposits and therefore supports site conditions more typical of mesophytic forests. As is common in lightly disturbed and undisturbed mesic upland sites throughout this region, mature stands in Trail of Tears State Forest are...

  2. Stand-level bird response to experimental forest management in the Missouri Ozarks

    Treesearch

    Sarah W. Kendrick; Paul A. Porneluzi; Frank R. Thompson; Dana L. Morris; Janet M. Haslerig; John Faaborg

    2015-01-01

    Long-term landscape-scale experiments allow for the detection of effects of silviculture on bird abundance. Manipulative studies allow for strong inference on effects and confirmation of patterns from observational studies.We estimated bird-territory density within forest stands (2.89-62 ha) for 19 years of the Missouri Ozark Forest Ecosystem Project (MOFEP), a 100-...

  3. Pre-wildfire fuel treatments affect long-term ponderosa pine forest dynamics

    Treesearch

    Barbara A. Strom; Peter Z. Fule

    2007-01-01

    The 2002 Rodeo-Chediski fire, the largest wildfire in south-western USA history, burned over treated stands and adjacent untreated stands in the Apache-Sitgreaves National Forest, setting the stage for a natural experiment testing the effectiveness of fuel reduction treatments under conditions of extraordinary fire severity. In seven pairs of treated­ untreated study...

  4. Approximations of stand water use versus evapotranspiration from three mangrove forests in southwest Florida, USA

    USGS Publications Warehouse

    Krauss, Ken W.; Barr, Jordan G.; Engel, Victor C.; Fuentes, Jose D.; Wang, Hongqing

    2014-01-01

    Leaves from mangrove forests are often considered efficient in the use of water during photosynthesis, but less is known about whole-tree and stand-level water use strategies. Are mangrove forests as conservative in water use as experimental studies on seedlings imply? Here, we apply a simple model to estimate stand water use (S), determine the contribution of S to evapotranspiration (ET), and approximate the distribution of S versus ET over annual cycles for three mangrove forests in southwest Florida, USA. The value of S ranged from 350 to 511 mm year−1 for two mangrove forests in Rookery Bay to 872 mm year−1 for a mangrove forest along the Shark River in Everglades National Park. This represents 34–49% of ET for Rookery Bay mangroves, a rather conservative rate ofS, and 63–66% of ET for the Shark River mangroves, a less conservative rate of S. However, variability in estimates of S in mangroves is high enough to require additional study on the spatial changes related to forest structural shifts, different tidal regimes, and variable site-specific salinity concentrations in multiple mangrove forests before a true account of water use conservation strategies can be understood at the landscape scale. Evidence does suggest that large, well-developed mangrove forests have the potential to contribute considerably to the ET balance; however, regionally most mangrove forests are much smaller in stature in Florida and likely contribute less to regional water losses through stand-level transpiration.

  5. Influence of disturbance on stand development during forest succession

    Treesearch

    Jeffrey S. Ward

    2013-01-01

    Eighty years of data on stand development on 39 strip transects were used to elucidate the influence of disturbance on forest composition. Transects were measured at 10-year intervals between 1927 and 2007, except for 1947, and the resulting data include records of 35,953 stems. Disturbances included a wildfire in 1932, single-year defoliations (1964, 1972, 1981), and...

  6. Effects of Dwarf Mistletoe on Stand Structure of Lodgepole Pine Forests 21-28 Years Post-Mountain Pine Beetle Epidemic in Central Oregon

    PubMed Central

    Agne, Michelle C.; Shaw, David C.; Woolley, Travis J.; Queijeiro-Bolaños, Mónica E.

    2014-01-01

    Lodgepole pine (Pinus contorta) forests are widely distributed throughout North America and are subject to mountain pine beetle (Dendroctonus ponderosae) epidemics, which have caused mortality over millions of hectares of mature trees in recent decades. Mountain pine beetle is known to influence stand structure, and has the ability to impact many forest processes. Dwarf mistletoe (Arceuthobium americanum) also influences stand structure and occurs frequently in post-mountain pine beetle epidemic lodgepole pine forests. Few studies have incorporated both disturbances simultaneously although they co-occur frequently on the landscape. The aim of this study is to investigate the stand structure of lodgepole pine forests 21–28 years after a mountain pine beetle epidemic with varying levels of dwarf mistletoe infection in the Deschutes National Forest in central Oregon. We compared stand density, stand basal area, canopy volume, proportion of the stand in dominant/codominant, intermediate, and suppressed cohorts, average height and average diameter of each cohort, across the range of dwarf mistletoe ratings to address differences in stand structure. We found strong evidence of a decrease in canopy volume, suppressed cohort height, and dominant/codominant cohort diameter with increasing stand-level dwarf mistletoe rating. There was strong evidence that as dwarf mistletoe rating increases, proportion of the stand in the dominant/codominant cohort decreases while proportion of the stand in the suppressed cohort increases. Structural differences associated with variable dwarf mistletoe severity create heterogeneity in this forest type and may have a significant influence on stand productivity and the resistance and resilience of these stands to future biotic and abiotic disturbances. Our findings show that it is imperative to incorporate dwarf mistletoe when studying stand productivity and ecosystem recovery processes in lodgepole pine forests because of its potential to

  7. Interactions of changing climate and shifts in forest composition on stand carbon balance

    Treesearch

    Chiang Jyh-Min; Louis Iverson; Anantha Prasad; Kim Brown

    2006-01-01

    Given that climate influences forest biogeographic distribution, many researchers have created models predicting shifts in tree species range with future climate change scenarios. The objective of this study is to investigate the forest carbon consequences of shifts in stand species composition with current and future climate scenarios using such a model.

  8. Understory plant development in artificial canopy gaps in an 81-year-old forest stand on Chichagof Island, southeast Alaska

    Treesearch

    Scott Harris; Jeffrey Barnard

    2017-01-01

    This study assesses the understory plant response and associated effects on forage resources available to Sitka black-tailed deer (Odocoileus hemionus sitkensis), to the creation of artificial canopy gaps in a young-growth forest stand in the coastal temperate rain forest of southeast Alaska. The forest stand was approximately 58 years old when gaps were created and...

  9. Tree regeneration spatial patterns in ponderosa pine forests following stand-replacing fire: Influence of topography and neighbors

    Treesearch

    Justin P. Ziegler; Chad M. Hoffman; Paula J. Fornwalt; Carolyn H. Sieg; Michael A. Battaglia; Marin E. Chambers; Jose M. Iniguez

    2017-01-01

    Shifting fire regimes alter forest structure assembly in ponderosa pine forests and may produce structural heterogeneity following stand-replacing fire due, in part, to fine-scale variability in growing environments. We mapped tree regeneration in eighteen plots 11 to 15 years after stand-replacing fire in Colorado and South Dakota, USA. We used point pattern analyses...

  10. How fast will trees die? A transition matrix model of ash decline in forest stands infested by emerald ash borer

    Treesearch

    Kathleen S. Knight; Robert P. Long; Joanne Rebbeck; Annemarie Smith; Kamal Gandhi; Daniel A. Herms

    2008-01-01

    We recorded Fraxinus spp. tree health and other forest stand characteristics for 68 plots in 21 EAB-infested forest stands in Michigan and Ohio in 2005 and 2007. Fraxinus spp. were a dominant component of these stands, with more than 900 ash trees (including Fraxinus americana, Fraxinus pennsylvanica, Fraxinus profunda...

  11. Passive restoration augments active restoration in deforested landscapes: the role of root suckering adjacent to planted stands of Acacia koa

    Treesearch

    Paul G. Scowcroft; Justin T. Yeh

    2013-01-01

    Active forest restoration in Hawaii’s Hakalau Forest National Wildlife Refuge has produced a network of Acacia koa tree corridors and islands in deforested grasslands. Passive restoration by root suckering has potential to expand tree cover and close gaps between planted stands. This study documents rates of encroachment into grassland, clonal...

  12. Stand-level variation in evapotranspiration in non-water-limited eucalypt forests

    NASA Astrophysics Data System (ADS)

    Benyon, Richard G.; Nolan, Rachael H.; Hawthorn, Sandra N. D.; Lane, Patrick N. J.

    2017-08-01

    To better understand water and energy cycles in forests over years to decades, measurements of spatial and long-term temporal variability in evapotranspiration (Ea) are needed. In mountainous terrain, plot-level measurements are important to achieving this. Forest inventory data including tree density and size measurements, often collected repeatedly over decades, sample the variability occurring within the geographic and topographic range of specific forest types. Using simple allometric relationships, tree stocking and size data can be used to estimate variables including sapwood area index (SAI), which may be strongly correlated with annual Ea. This study analysed plot-level variability in SAI and its relationship with overstorey and understorey transpiration, interception and evaporation over a 670 m elevation gradient, in non-water-limited, even-aged stands of Eucalyptus regnans F. Muell. to determine how well spatial variation in annual Ea from forests can be mapped using SAI. Over the 3 year study, mean sap velocity in five E. regnans stands was uncorrelated with overstorey sapwood area index (SAI) or elevation: annual transpiration was predicted well by SAI (R2 0.98). Overstorey and total annual interception were positively correlated with SAI (R2 0.90 and 0.75). Ea from the understorey was strongly correlated with vapour pressure deficit (VPD) and net radiation (Rn) measured just above the understorey, but relationships between understorey Ea and VPD and Rn differed between understorey types and understorey annual Ea was not correlated with SAI. Annual total Ea was also strongly correlated with SAI: the relationship being similar to two previous studies in the same region, despite differences in stand age and species. Thus, spatial variation in annual Ea can be reliably mapped using measurements of SAI.

  13. Grapevine dynamics after manual tending of juvenile stands on the Hoosier National Forest, Indiana

    Treesearch

    Robert C. Morrissey; Martin-Michel Gauthier; John A., Jr. Kershaw; Douglass F. Jacobs; Burnell C. Fischer; John R. Siefert

    2008-01-01

    Large woody vines, most notably grapevines, are a source of great concern for forest and wildlife managers in many parts of the Central Hardwood Forest Region of the United States. We examined grapevine dynamics in stands aged 21 - 35 years. The plots, located in regenerated clearcuts in the Hoosier National Forest (HNF), were evaluated for vine control, site, and tree...

  14. Imputing forest structure attributes from stand inventory and remotely sensed data in western Oregon, USA

    Treesearch

    Andrew T. Hudak; A. Tod Haren; Nicholas L. Crookston; Robert J. Liebermann; Janet L. Ohmann

    2014-01-01

    Imputation is commonly used to assign reference stand observations to target stands based on covariate relationships to remotely sensed data to assign inventory attributes across the entire landscape. However, most remotely sensed data are collected at higher resolution than the stand inventory data often used by operational foresters. Our primary goal was to compare...

  15. The nature of the beast: examining climate adaptation options in forests with stand-replacing fire regimes

    Treesearch

    Joshua S. Halofsky; Daniel C. Donato; Jerry F. Franklin; Jessica E. Halofsky; David L. Peterson; Brian J. Harvey

    2018-01-01

    Building resilience to natural disturbances is a key to managing forests for adaptation to climate change. To date, most climate adaptation guidance has focused on recommendations for frequent-fire forests, leaving few published guidelines for forests that naturally experience infrequent, stand-replacing wildfires. Because most such forests are inherently resilient to...

  16. Carbon accretion in unthinned and thinned young-growth forest stands of the Alaskan perhumid coastal temperate rainforest.

    PubMed

    D'Amore, David V; Oken, Kiva L; Herendeen, Paul A; Steel, E Ashley; Hennon, Paul E

    2015-12-01

    Accounting for carbon gains and losses in young-growth forests is a key part of carbon assessments. A common silvicultural practice in young forests is thinning to increase the growth rate of residual trees. However, the effect of thinning on total stand carbon stock in these stands is uncertain. In this study we used data from 284 long-term growth and yield plots to quantify the carbon stock in unthinned and thinned young growth conifer stands in the Alaskan coastal temperate rainforest. We estimated carbon stocks and carbon accretion rates for three thinning treatments (basal area removal of 47, 60, and 73 %) and a no-thin treatment across a range of productivity classes and ages. We also accounted for the carbon content in dead trees to quantify the influence of both thinning and natural mortality in unthinned stands. The total tree carbon stock in naturally-regenerating unthinned young-growth forests estimated as the asymptote of the accretion curve was 484 (±26) Mg C ha -1 for live and dead trees and 398 (±20) Mg C ha -1 for live trees only. The total tree carbon stock was reduced by 16, 26, and 39 % at stand age 40 y across the increasing range of basal area removal. Modeled linear carbon accretion rates of stands 40 years after treatment were not markedly different with increasing intensity of basal area removal from reference stand values of 4.45 Mg C ha -1  year -1 to treatment stand values of 5.01, 4.83, and 4.68 Mg C ha -1  year -1 respectively. However, the carbon stock reduction in thinned stands compared to the stock of carbon in the unthinned plots was maintained over the entire 100 year period of observation. Thinning treatments in regenerating forest stands reduce forest carbon stocks, while carbon accretion rates recovered and were similar to unthinned stands. However, that the reduction of carbon stocks in thinned stands persisted for a century indicate that the unthinned treatment option is the optimal choice for short

  17. Effects of even-aged management on forest birds at northern hardwood stand interfaces

    Treesearch

    Richard M. DeGraaf

    1992-01-01

    Breeding birds were counted along transects across edges of even-aged northern hardwood stands in the White Mountain National Forest, New Hampshire, U.S.A. Two replicate transects across each of 7 edge types representing 3 classes of contrast (abrupt, intermediate, and subtle) were sampled during June 1983-1985 to define species assemblages at stand edges and estimate...

  18. Cutting a young-growth, mixed-conifer stand to California Forest Practice Act Standards

    Treesearch

    Philip M. McDonald

    1973-01-01

    Cutting by the minimum standard of the Rules of California's North Sierra Pine Forest District was evaluated for effects on species composition, seed fall, regeneration, and residual growth at the Challenge Experimental Forest, central California. Cutting removed 74 percent of the stand basal area and 94 percent of the merchantable volume. The heavy cut changed...

  19. Temperature and Soil Moisture Regimes In and Adjacent to the Fernow Experimental Forest

    Treesearch

    Jerry T. Crews; Linton Wright

    2000-01-01

    The effects of elevation, aspect, ambient air temperature, and soil moisture on soil temperature were examined in and adjacent to the Fernow Experimental Forest in West Virginia to determine the extent of frigid soils. The mean annual temperature of frigid soils ranges from 1? to 7?C at a depth of 50 cm; the difference between mean winter and mean summer temperatures...

  20. Diameter distribution in a Brazilian tropical dry forest domain: predictions for the stand and species.

    PubMed

    Lima, Robson B DE; Bufalino, Lina; Alves, Francisco T; Silva, José A A DA; Ferreira, Rinaldo L C

    2017-01-01

    Currently, there is a lack of studies on the correct utilization of continuous distributions for dry tropical forests. Therefore, this work aims to investigate the diameter structure of a brazilian tropical dry forest and to select suitable continuous distributions by means of statistic tools for the stand and the main species. Two subsets were randomly selected from 40 plots. Diameter at base height was obtained. The following functions were tested: log-normal; gamma; Weibull 2P and Burr. The best fits were selected by Akaike's information validation criterion. Overall, the diameter distribution of the dry tropical forest was better described by negative exponential curves and positive skewness. The forest studied showed diameter distributions with decreasing probability for larger trees. This behavior was observed for both the main species and the stand. The generalization of the function fitted for the main species show that the development of individual models is needed. The Burr function showed good flexibility to describe the diameter structure of the stand and the behavior of Mimosa ophthalmocentra and Bauhinia cheilantha species. For Poincianella bracteosa, Aspidosperma pyrifolium and Myracrodum urundeuva better fitting was obtained with the log-normal function.

  1. Regeneration Potential of Selected Forested Stands on the Cumberland Plateau of North Alabama

    Treesearch

    Callie Jo Schweitzer; David L. Loftis; Yong Wang; Greg C. Janzen

    2004-01-01

    Forested areas in the Cumberland Plateau region have experienced a myriad of disturbances over the last century. As a result, hardwood forests, such as those found in north Alabama, contain a mixture of species with wide ranges of shade tolerance and growth rates. Both site characteristics and past disturbance history have contributed to stands that are considered low...

  2. Some Forest Floor Fuelbed Characteristics of Black Oak Stands in Southeast Missouri

    Treesearch

    John S. Crosby; Robert M. Loomis

    1974-01-01

    Black oak forest floor fuelbeds under 20 - and 40-year-old stands in southeast Missouri averaged 6.4 and 4.2 inches in depth, respectively. Loose Litter averaged 2.0 and 2.9 tons per acre and 3.3 inces in depth. Bulk density of litter averaged 0.33 and 0.49 lb/ft3 and of total forest floor 0.89 and 1.10 lbs/ft3, respectively.

  3. Functional groups show distinct differences in nitrogen cycling during early stand development: implications for forest management.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Aubrey, Doug, P.; Coyle, David, R. Coleman, Mark, D.

    2011-08-26

    Nutrient acquisition of forest stands is controlled by soil resource availability and belowground production, but tree species are rarely compared in this regard. Here, we examine ecological and management implications of nitrogen (N) dynamics during early forest stand development in productive commercial tree species with narrow (Populus deltoides Bartr. and Platanus occidentalis L.) and broad (Liquidambar styraciflua L. and Pinus taeda L.) site requirements while grown with a range of nutrient and water resources. We constructed N budgets by measuring N concentration ([N]) and N content (N{sub C}) of above- and belowground perennial and ephemeral tissues, determined N uptake (N{submore » UP}), and calculated N use efficiency (NUE). Forest stands regulated [N] within species-specific operating ranges without clear temporal or treatment patterns, thus demonstrating equilibrium between tissue [N] and biomass accumulation. Forest stand N{sub C} and N{sub UP} increased with stand development and paralleled treatment patterns of biomass accumulation, suggesting productivity is tightly linked to N{sub UP}. Inclusion of above- and belowground ephemeral tissue turnover in N{sub UP} calculations demonstrated that maximum N demand for narrow-sites adapted species exceeded 200 kg N ha{sup -1} year{sup -1} while demand for broad-site adapted species was below this level. NUE was species dependent but not consistently influenced by N availability, suggesting relationships between NUE and resource availability were species dependent. Based on early stand development, species with broad site adaptability are favored for woody cropping systems because they maintain high above- and belowground productivity with minimal fertilization requirements due to higher NUE than narrow site adapted species.« less

  4. Agricultural legacies in forest environments: tree communities, soil properties, and light availability.

    PubMed

    Flinn, Kathryn M; Marks, P L

    2007-03-01

    Temperate deciduous forests across much of Europe and eastern North America reflect legacies of past land use, particularly in the diversity and composition of plant communities. Intense disturbances, such as clearing forests for agriculture, may cause persistent environmental changes that continue to shape vegetation patterns as landscapes recover. We assessed the long-term consequences of agriculture for environmental conditions in central New York forests, including tree community structure and composition, soil physical and chemical properties, and light availability. To isolate the effects of agriculture, we compared 20 adjacent pairs of forests that were never cleared for agriculture (primary forests) and forests that established 85-100 years ago on plowed fields (secondary forests). Tree communities in primary and secondary forests had similar stem density, though secondary forests had 14% greater basal area. Species composition differed dramatically between the two forest types, with primary forests dominated by Acer saccharum and Fagus grandifolia and secondary forests by Acer rubrum and Pinus strobus. Primary and secondary forests showed no consistent differences in soil physical properties or in the principal gradient of soil fertility associated with soil pH. Within stands, however, soil water content and pH were more variable in primary forests. Secondary forest soils had 15% less organic matter, 16% less total carbon, and 29% less extractable phosphorus in the top 10 cm than adjacent primary stands, though the ranges of the forest types mostly overlapped. Understory light availability in primary and secondary forests was similar. These results suggest that, within 100 years, post-agricultural stands have recovered conditions comparable to less disturbed forests in many attributes, including tree size and number, soil physical properties, soil chemical properties associated with pH, and understory light availability. The principal legacies of

  5. Forest structure, stand composition, and climate-growth response in montane forests of Jiuzhaigou National Nature Reserve, China.

    PubMed

    Schwartz, Mark W; Dolanc, Christopher R; Gao, Hui; Strauss, Sharon Y; Schwartz, Ari C; Williams, John N; Tang, Ya

    2013-01-01

    Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1) whether the forest appears in transition toward increased hardwood composition; 2) if conifers appear stressed by recent climate change relative to hardwoods; and 3) how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20(th) century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix) strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth.

  6. Forest Structure, Stand Composition, and Climate-Growth Response in Montane Forests of Jiuzhaigou National Nature Reserve, China

    PubMed Central

    Schwartz, Mark W.; Dolanc, Christopher R.; Gao, Hui; Strauss, Sharon Y.; Schwartz, Ari C.; Williams, John N.; Tang, Ya

    2013-01-01

    Montane forests of western China provide an opportunity to establish baseline studies for climate change. The region is being impacted by climate change, air pollution, and significant human impacts from tourism. We analyzed forest stand structure and climate-growth relationships from Jiuzhaigou National Nature Reserve in northwestern Sichuan province, along the eastern edge of the Tibetan plateau. We conducted a survey to characterize forest stand diversity and structure in plots occurring between 2050 and 3350 m in elevation. We also evaluated seedling and sapling recruitment and tree-ring data from four conifer species to assess: 1) whether the forest appears in transition toward increased hardwood composition; 2) if conifers appear stressed by recent climate change relative to hardwoods; and 3) how growth of four dominant species responds to recent climate. Our study is complicated by clear evidence of 20th century timber extraction. Focusing on regions lacking evidence of logging, we found a diverse suite of conifers (Pinus, Abies, Juniperus, Picea, and Larix) strongly dominate the forest overstory. We found population size structures for most conifer tree species to be consistent with self-replacement and not providing evidence of shifting composition toward hardwoods. Climate-growth analyses indicate increased growth with cool temperatures in summer and fall. Warmer temperatures during the growing season could negatively impact conifer growth, indicating possible seasonal climate water deficit as a constraint on growth. In contrast, however, we found little relationship to seasonal precipitation. Projected warming does not yet have a discernible signal on trends in tree growth rates, but slower growth with warmer growing season climates suggests reduced potential future forest growth. PMID:23951188

  7. Predicting the rate of change in timber value for forest stands infested with gypsy moth

    Treesearch

    David A. Gansner; Owen W. Herrick

    1982-01-01

    Presents a method for estimating the potential impact of gypsy moth attacks on forest-stand value. Robust regression analysis is used to develop an equation for predicting the rate of change in timber value from easy-to-measure key characteristics of stand condition.

  8. Does Hawaiian native forest conserve water? Lower uptake rates at tree and stand scale by Metrosideros polymorpha relative to plantation species

    NASA Astrophysics Data System (ADS)

    Kagawa, A. K.; Sack, L.; Duarte, T. K.; James, S. A.

    2007-12-01

    Native plants are often claimed to be conservative water users that enhance groundwater recharge compared to faster-growing non-native species that tend to dominate watersheds. This argument would have implications for motivating conservation and restoration of native forest in Hawai'i. However, few studies have examined differences in native and non-native plant transpiration (water use) at species or at stand level. Our aim was determine whether species matter to stand-level water use. We measured plant transpiration in a continuous mosaic of native forest and non-native tree plantation in Honaunau, Hawaii, focusing on endemic dominant tree Metrosideros polymorpha, alien timber trees Eucalyptus saligna and Fraxinus uhdei, and dominant understory Cibotium tree ferns. We measured xylem sap flow for six individuals of each species continuously for over eight weeks, and we estimated stand water use by scaling up these measurements using stand sapwood area and tree fern leaf area values obtained through vegetation surveys. Native forest dominant Metrosideros had the lowest rates of whole-tree daily water use at 8 kg day-1 (200kg m-2sapwood day-1), less than half the daily rates for Eucalyptus or Fraxinus; Metrosideros also had the lowest maximum transpiration rates of the three tree species. At the stand level, Fraxinus-dominated stands had higher water use than Eucalyptus- and Metrosideros- dominated stands due to the species' high sap flow rates, five-fold greater sapwood allocation, and the stands' two-fold greater dominant tree density. In Metrosideros-dominated stands, high Cibotium tree fern leaf area contributed to nearly 60% of water use, indicating the fern's critical role in forest water balance. Stand water use was influenced by factors at various scales, including species composition, stem density, tree sizes, and tree species' sapwood allocation, and was affected significantly by understory contributions. These findings highlight the importance of

  9. Influence of Anthropogenic Disturbances on Stand Structural Complexity in Andean Temperate Forests: Implications for Managing Key Habitat for Biodiversity.

    PubMed

    Caviedes, Julián; Ibarra, José Tomás

    2017-01-01

    Forest attributes and their abundances define the stand structural complexity available as habitat for faunal biodiversity; however, intensive anthropogenic disturbances have the potential to degrade and simplify forest stands. In this paper we develop an index of stand structural complexity and show how anthropogenic disturbances, namely fire, logging, livestock, and their combined presence, affect stand structural complexity in a southern Global Biodiversity Hotspot. From 2011 to 2013, we measured forest structural attributes as well as the presence of anthropogenic disturbances in 505 plots in the Andean zone of the La Araucanía Region, Chile. In each plot, understory density, coarse woody debris, number of snags, tree diameter at breast height, and litter depth were measured, along with signs of the presence of anthropogenic disturbances. Ninety-five percent of the plots showed signs of anthropogenic disturbance (N = 475), with the combined presence of fire, logging, and livestock being the most common disturbance (N = 222; 44% of plots). The lowest values for the index were measured in plots combining fire, logging, and livestock. Undisturbed plots and plots with the presence of relatively old fires (> 70 years) showed the highest values for the index of stand structural complexity. Our results suggest that secondary forests < 70-year post-fire event, with the presence of habitat legacies (e.g. snags and CWD), can reach a structural complexity as high as undisturbed plots. Temperate forests should be managed to retain structural attributes, including understory density (7.2 ± 2.5 # contacts), volume of CWD (22.4 ± 25.8 m3/ha), snag density (94.4 ± 71.0 stems/ha), stand basal area (61.2 ± 31.4 m2/ha), and litter depth (7.5 ± 2.7 cm). Achieving these values will increase forest structural complexity, likely benefiting a range of faunal species in South American temperate forests.

  10. Influence of Anthropogenic Disturbances on Stand Structural Complexity in Andean Temperate Forests: Implications for Managing Key Habitat for Biodiversity

    PubMed Central

    2017-01-01

    Forest attributes and their abundances define the stand structural complexity available as habitat for faunal biodiversity; however, intensive anthropogenic disturbances have the potential to degrade and simplify forest stands. In this paper we develop an index of stand structural complexity and show how anthropogenic disturbances, namely fire, logging, livestock, and their combined presence, affect stand structural complexity in a southern Global Biodiversity Hotspot. From 2011 to 2013, we measured forest structural attributes as well as the presence of anthropogenic disturbances in 505 plots in the Andean zone of the La Araucanía Region, Chile. In each plot, understory density, coarse woody debris, number of snags, tree diameter at breast height, and litter depth were measured, along with signs of the presence of anthropogenic disturbances. Ninety-five percent of the plots showed signs of anthropogenic disturbance (N = 475), with the combined presence of fire, logging, and livestock being the most common disturbance (N = 222; 44% of plots). The lowest values for the index were measured in plots combining fire, logging, and livestock. Undisturbed plots and plots with the presence of relatively old fires (> 70 years) showed the highest values for the index of stand structural complexity. Our results suggest that secondary forests < 70-year post-fire event, with the presence of habitat legacies (e.g. snags and CWD), can reach a structural complexity as high as undisturbed plots. Temperate forests should be managed to retain structural attributes, including understory density (7.2 ± 2.5 # contacts), volume of CWD (22.4 ± 25.8 m3/ha), snag density (94.4 ± 71.0 stems/ha), stand basal area (61.2 ± 31.4 m2/ha), and litter depth (7.5 ± 2.7 cm). Achieving these values will increase forest structural complexity, likely benefiting a range of faunal species in South American temperate forests. PMID:28068349

  11. Vegetative conditions and management options in even-age stands on the Monongahela National Forest

    Treesearch

    Gary W. Miller; James N. Kochenderfer; James Knibbs; John E. Baumgras

    2001-01-01

    In 1998, personnel with the Northeastern Research Station and the Monongahela National Forest initiated a comprehensive survey of even-age stands that regenerated between 1964 and 1990. Preliminary results indicate that clearcutting was successful in regenerating these young stands with a variety of woody and herbaceous plant species. Early cleanings using crop-tree...

  12. Movements of northern flying squirrels in different-aged forest stands of western Oregon

    USGS Publications Warehouse

    Martin, K.J.; Anthony, R.G.

    1999-01-01

    In western Oregon, northern flying squirrels (Glaucomys sabrinus) are the primary prey species for northern spotted owls (Strix occidentalis caurina), an old-growth associated species. To assess differences between old-growth and second-growth habitat, we livetrapped and radiotagged 39 northern flying squirrels to estimate their home range sizes and describe movements in 2 old-growth and 2 second-growth conifer forest stands in the Cascade Mountains of central Oregon. Sampling periods were summer and fall of 1991-92. Home range sizes averaged 4.9 ha and did not differ (P > 0.30) between the 2 stand types. Male northern flying squirrels had larger (P ??? 0.03) mean home ranges (5.9 ?? 0.8 ha; ?? ?? SE; n = 20) than females (3.9 ?? 0.4 ha; n = 19). Northern flying squirrel movement distances between successive, noncorrelated telemetry locations averaged 71 m (n = 1,090). No correlation was found between distances moved and stand type or sex. Northern flying squirrel's home range sizes, movements, and densities were similar between the 2 stand types. We suggest abundance and movements of northern flying squirrels are not influencing the preferential selection of oldgrowth forests by northern spotted owls.

  13. Measuring Effective Leaf Area Index, Foliage Profile, and Stand Height in New England Forest Stands Using a Full-Waveform Ground-Based Lidar

    NASA Technical Reports Server (NTRS)

    Zhao, Feng; Yang, Xiaoyuan; Schull, Mithcell A.; Roman-Colon, Miguel O.; Yao, Tian; Wang, Zhuosen; Zhang, Qingling; Jupp, David L. B.; Lovell, Jenny L.; Culvenor, Darius; hide

    2011-01-01

    Effective leaf area index (LAI) retrievals from a scanning, ground-based, near-infrared (1064 nm) lidar that digitizes the full return waveform, the Echidna Validation Instrument (EVI), are in good agreement with those obtained from both hemispherical photography and the Li-Cor LAI-2000 Plant Canopy Analyzer. We conducted trials at 28 plots within six stands of hardwoods and conifers of varying height and stocking densities at Harvard Forest, Massachusetts, Bartlett Experimental Forest, New Hampshire, and Howland Experimental Forest, Maine, in July 2007. Effective LAI values retrieved by four methods, which ranged from 3.42 to 5.25 depending on the site and method, were not significantly different ( b0.1 among four methods). The LAI values also matched published values well. Foliage profiles (leaf area with height) retrieved from the lidar scans, although not independently validated, were consistent with stand structure as observed and as measured by conventional methods. Canopy mean top height, as determined from the foliage profiles, deviated from mean RH100 values obtained from the Lidar Vegetation Imaging Sensor (LVIS) airborne large-footprint lidar system at 27 plots by .0.91 m with RMSE=2.04 m, documenting the ability of the EVI to retrieve stand height. The Echidna Validation Instrument is the first realization of the Echidna lidar concept, devised by Australia's Commonwealth Scientific and Industrial Research Organization (CSIRO), for measuring forest structure using full-waveform, ground-based, scanning lidar.

  14. Forest adjacent households' voices on their perceptions and adaptation strategies to climate change in Kilombero District, Tanzania.

    PubMed

    Balama, Chelestino; Augustino, Suzana; Eriksen, Siri; Makonda, Fortunatus B S

    2016-01-01

    Climate change is a global and local challenge to both sustainable livelihoods and economic development. Tanzania as other countries of the world has been affected. Several studies have been conducted on farmers' perceptions and adaptation to climate change in the country, but little attention has been devoted to forest adjacent households in humid areas. This study assessed this gap through assessing forest adjacent households' voices on perceptions and adaptation strategies to climate change in Kilombero District, Tanzania. Data collection involved key informant interviews, focus group discussions and household questionnaires. Results showed that the majority of households perceived changed climate in terms of temperature increase, unpredictable rainfall, frequent occurrence of floods, increased dry spells during rainy season coupled with decreased water sources and emergence of new pests and diseases. The perceived change in climate has impacted agriculture productivity as the main livelihood source. Different coping and adaptation strategies are employed. These are; crop diversification, changing cropping calendar, adopting modern farming technologies, and increasing reliance on non-timber forest products. These strategies were positively and significantly influenced by socio-economic factors including household size, residence period, land ownership and household income. The study concludes that, there are changes in climatic conditions; and to respond to these climatic changes, forest adjacent households have developed numerous coping and adaptation strategies, which were positively and significantly influenced by some socio-economic factors. The study calls for actual implementation of local climate change policies and strategies in order to enhance adaptive capacity at household level.

  15. CLIMACS: a computer model of forest stand development for western Oregon and Washington.

    Treesearch

    Virginia H. Dale; Miles Hemstrom

    1984-01-01

    A simulation model for the development of timber stands in the Pacific Northwest is described. The model grows individual trees of 21 species in a 0.20-hectare (0.08-acre) forest gap. The model provides a means of assimilating existing information, indicates where knowledge is deficient, suggests where the forest system is most sensitive, and provides a first testing...

  16. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    USGS Publications Warehouse

    Yue, C.; Ciais, P.; Luyssaert, S.; Cadule, P.; Harden, J.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S.L.; Poulter, B.; Viovy, N.

    2013-01-01

    Stand-replacing fires are the dominant fire type in North American boreal forests. They leave a historical legacy of a mosaic landscape of different aged forest cohorts. This forest age dynamics must be included in vegetation models to accurately quantify the role of fire in the historical and current regional forest carbon balance. The present study adapted the global process-based vegetation model ORCHIDEE to simulate the CO2 emissions from boreal forest fire and the subsequent recovery after a stand-replacing fire; the model represents postfire new cohort establishment, forest stand structure and the self-thinning process. Simulation results are evaluated against observations of three clusters of postfire forest chronosequences in Canada and Alaska. The variables evaluated include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index, and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). When forced by local climate and the atmospheric CO2 history at each chronosequence site, the model simulations generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with the measurement accuracy (for CO2 flux ~100 g C m−2 yr−1, for biomass carbon ~1000 g C m−2 and for soil carbon ~2000 g C m−2). We find that the current postfire forest carbon sink at the evaluation sites, as observed by chronosequence methods, is mainly due to a combination of historical CO2 increase and forest succession. Climate change and variability during this period offsets some of these expected carbon gains. The negative impacts of climate were a likely consequence of increasing water stress caused by significant temperature increases that were not matched by concurrent increases in precipitation. Our simulation

  17. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    NASA Astrophysics Data System (ADS)

    Yue, C.; Ciais, P.; Luyssaert, S.; Cadule, P.; Harden, J.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S. L.; Poulter, B.; Viovy, N.

    2013-04-01

    Stand-replacing fires are the dominant fire type in North American boreal forest and leave a historical legacy of a mosaic landscape of different aged forest cohorts. To accurately quantify the role of fire in historical and current regional forest carbon balance using models, one needs to explicitly simulate the new forest cohort that is established after fire. The present study adapted the global process-based vegetation model ORCHIDEE to simulate boreal forest fire CO2 emissions and follow-up recovery after a stand-replacing fire, with representation of postfire new cohort establishment, forest stand structure and the following self-thinning process. Simulation results are evaluated against three clusters of postfire forest chronosequence observations in Canada and Alaska. Evaluation variables for simulated postfire carbon dynamics include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index (LAI), and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). The model simulation results, when forced by local climate and the atmospheric CO2 history on each chronosequence site, generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with measurement accuracy (for CO2 flux ~100 g C m-2 yr-1, for biomass carbon ~1000 g C m-2 and for soil carbon ~2000 g C m-2). We find that current postfire forest carbon sink on evaluation sites observed by chronosequence methods is mainly driven by historical atmospheric CO2 increase when forests recover from fire disturbance. Historical climate generally exerts a negative effect, probably due to increasing water stress caused by significant temperature increase without sufficient increase in precipitation. Our simulation results demonstrate that a global

  18. Simulating boreal forest carbon dynamics after stand-replacing fire disturbance: insights from a global process-based vegetation model

    NASA Astrophysics Data System (ADS)

    Yue, C.; Ciais, P.; Luyssaert, S.; Cadule, P.; Harden, J.; Randerson, J.; Bellassen, V.; Wang, T.; Piao, S. L.; Poulter, B.; Viovy, N.

    2013-12-01

    Stand-replacing fires are the dominant fire type in North American boreal forests. They leave a historical legacy of a mosaic landscape of different aged forest cohorts. This forest age dynamics must be included in vegetation models to accurately quantify the role of fire in the historical and current regional forest carbon balance. The present study adapted the global process-based vegetation model ORCHIDEE to simulate the CO2 emissions from boreal forest fire and the subsequent recovery after a stand-replacing fire; the model represents postfire new cohort establishment, forest stand structure and the self-thinning process. Simulation results are evaluated against observations of three clusters of postfire forest chronosequences in Canada and Alaska. The variables evaluated include: fire carbon emissions, CO2 fluxes (gross primary production, total ecosystem respiration and net ecosystem exchange), leaf area index, and biometric measurements (aboveground biomass carbon, forest floor carbon, woody debris carbon, stand individual density, stand basal area, and mean diameter at breast height). When forced by local climate and the atmospheric CO2 history at each chronosequence site, the model simulations generally match the observed CO2 fluxes and carbon stock data well, with model-measurement mean square root of deviation comparable with the measurement accuracy (for CO2 flux ~100 g C m-2 yr-1, for biomass carbon ~1000 g C m-2 and for soil carbon ~2000 g C m-2). We find that the current postfire forest carbon sink at the evaluation sites, as observed by chronosequence methods, is mainly due to a combination of historical CO2 increase and forest succession. Climate change and variability during this period offsets some of these expected carbon gains. The negative impacts of climate were a likely consequence of increasing water stress caused by significant temperature increases that were not matched by concurrent increases in precipitation. Our simulation results

  19. Wildlife Habitat Conditions in Mature Pine Hardwood Stands in the Ouachita/Ozark National Forests

    Treesearch

    Ronald E. Thill; Philip A. Tappe; Nancy E. Koerth

    1994-01-01

    A long-term, stand-level, interdisciplinsry research and demonstration project was initiated on the Ouachia (ONF) and Ozark-St. Francis National Forests in Arkansas in 1990 to compare the impacts of alternative reproduction cutting methods on commodity and noncommodity forest resources including wildlife habitat and populations. Habitat masurement procedures and...

  20. Illustrating harvest effects on site microclimate in a high-elevation forest stand.

    Treesearch

    W.B. Fowler; T.D. Anderson

    1987-01-01

    Three-dimensional contour surfaces were drawn for physiologically active radiation (PAR) and air and soil temperatures from measurements taken at a high-elevation site (1450 m) near the crest of the Cascade Range in central Washington. Measurements in a clearcut were compared with measurements from an adjacent uncut stand. Data for 31 days in July and August 1985...

  1. Relationships between net primary productivity and stand age for several forest types and their influence on China's carbon balance.

    PubMed

    Wang, Shaoqiang; Zhou, Lei; Chen, Jingming; Ju, Weimin; Feng, Xianfeng; Wu, Weixing

    2011-06-01

    Affected by natural and anthropogenic disturbances such as forest fires, insect-induced mortality and harvesting, forest stand age plays an important role in determining the distribution of carbon pools and fluxes in a variety of forest ecosystems. An improved understanding of the relationship between net primary productivity (NPP) and stand age (i.e., age-related increase and decline in forest productivity) is essential for the simulation and prediction of the global carbon cycle at annual, decadal, centurial, or even longer temporal scales. In this paper, we developed functions describing the relationship between national mean NPP and stand age using stand age information derived from forest inventory data and NPP simulated by the BEPS (Boreal Ecosystem Productivity Simulator) model in 2001. Due to differences in ecobiophysical characteristics of different forest types, NPP-age equations were developed for five typical forest ecosystems in China (deciduous needleleaf forest (DNF), evergreen needleleaf forest in tropic and subtropical zones (ENF-S), deciduous broadleaf forest (DBF), evergreen broadleaf forest (EBF), and mixed broadleaf forest (MBF)). For DNF, ENF-S, EBF, and MBF, changes in NPP with age were well fitted with a common non-linear function, with R(2) values equal to 0.90, 0.75, 0.66, and 0.67, respectively. In contrast, a second order polynomial was best suitable for simulating the change of NPP for DBF, with an R(2) value of 0.79. The timing and magnitude of the maximum NPP varied with forest types. DNF, EBF, and MBF reached the peak NPP at the age of 54, 40, and 32 years, respectively, while the NPP of ENF-S maximizes at the age of 13 years. The highest NPP of DBF appeared at 122 years. NPP was generally lower in older stands with the exception of DBF, and this particular finding runs counter to the paradigm of age-related decline in forest growth. Evaluation based on measurements of NPP and stand age at the plot-level demonstrates the reliability

  2. Roosevelt elk selection of temperate rain forest seral stages in western Washington

    USGS Publications Warehouse

    Schroer, Greg L.; Jenkins, Kurt J.; Moorhead, Bruce B.

    1993-01-01

    We studied habitat selection by Roosevelt elk (Cervus elaphus roosevelti) in a temperate rain forest in the lower Queets River Valley of the western Olympic Peninsula, Washington from June 1986-July 1987. Elk annual home ranges included predominantly unlogged forests protected within Olympic National Park and logged, regenerating forests adjacent to the park. Radio-collared elk selected valley floors during all seasons except winter, when elk frequently used an adjoining plateau 60 m above the floodplain. In winder, radio-collared elk selected 6-15 year-old clearcuts, which were available on the plateau. Elk selected mature deciduous forests of the valley floor during spring, summer, and autumn, and generally they selected old-age Sitka spruce forests during autumn and winter. Young clearcuts (1-5 years old) and even-aged, regenerating stands (16-150 years old) generally were avoided during all seasons. Management practices that retain preferred habitat of elk, such as deciduous forests, 6-15 yr-old coniferous stands, and old-age coniferous bottomland forests will benefit elk, particularly on elk ranges managed for short-rotation, even-aged stands. Silvicultural alternatives to typical even-aged stand management, such as uneven-aged management and commercial thinning, should also be considered for improving and maintaining interspersion of forage and cover.

  3. Tree Diversity Enhances Stand Carbon Storage but Not Leaf Area in a Subtropical Forest.

    PubMed

    Castro-Izaguirre, Nadia; Chi, Xiulian; Baruffol, Martin; Tang, Zhiyao; Ma, Keping; Schmid, Bernhard; Niklaus, Pascal A

    2016-01-01

    Research about biodiversity-productivity relationships has focused on herbaceous ecosystems, with results from tree field studies only recently beginning to emerge. Also, the latter are concentrated largely in the temperate zone. Tree species diversity generally is much higher in subtropical and tropical than in temperate or boreal forests, with reasons not fully understood. Niche overlap and thus complementarity in the use of resources that support productivity may be lower in forests than in herbaceous ecosystems, suggesting weaker productivity responses to diversity change in forests. We studied stand basal area, vertical structure, leaf area, and their relationship with tree species richness in a subtropical forest in south-east China. Permanent forest plots of 30 x 30 m were selected to span largely independent gradients in tree species richness and secondary successional age. Plots with higher tree species richness had a higher stand basal area. Also, stand basal area increases over a 4-year census interval were larger at high than at low diversity. These effects translated into increased carbon stocks in aboveground phytomass (estimated using allometric equations). A higher variability in tree height in more diverse plots suggested that these effects were facilitated by denser canopy packing due to architectural complementarity between species. In contrast, leaf area was not or even negatively affected by tree diversity, indicating a decoupling of carbon accumulation from leaf area. Alternatively, the same community leaf area might have assimilated more C per time interval in more than in less diverse plots because of differences in leaf turnover and productivity or because of differences in the display of leaves in vertical and horizontal space. Overall, our study suggests that in species-rich forests niche-based processes support a positive diversity-productivity relationship and that this translates into increased carbon storage in long-lived woody

  4. New methods for estimating parameters of weibull functions to characterize future diameter distributions in forest stands

    Treesearch

    Quang V. Cao; Shanna M. McCarty

    2006-01-01

    Diameter distributions in a forest stand have been successfully characterized by use of the Weibull function. Of special interest are cases where parameters of a Weibull distribution that models a future stand are predicted, either directly or indirectly, from current stand density and dominant height. This study evaluated four methods of predicting the Weibull...

  5. Effects of climate, CO2 concentration, nitrogen deposition, and stand age changes on the carbon budget of China's forests

    NASA Astrophysics Data System (ADS)

    Zhang, C.; Ju, W.; Zhang, F.; Mao, D.; Wang, X.

    2017-12-01

    Forests play an irreplaceable role in the Earth's terrestrial carbon budget which retard the atmospheric CO2 buildup. Understanding the factors controlling forest carbon budget is critical for reducing uncertainties in projections of future climate. The relative importance of climate, atmospheric CO2 concentration, nitrogen deposition, and stand age changes on carbon budget, however, remains unclear for China's forests. In this study, we quantify individual contribution of these drivers to the trends of forest carbon budget in China from 1901 to 2012 by integrating national datasets, the updated Integrated Terrestrial Ecosystem Carbon Cycle (InTEC) model and factorial simulations. Results showed that the average carbon sink in China's forests from 1982 to 2012 was 186.9 Tg C yr-1 with 68% (127.6 Tg C yr-1) of the sink in living biomass because of the integrated effects of climate, atmospheric CO2 concentration, nitrogen deposition, and stand age factors. Compared with the simulation of all factors combined, the estimated carbon sink during 1901-2012 would be reduced by 41.8 Tg C yr-1 if climate change, atmospheric CO2 concentration and nitrogen deposition factors were omitted, and reduced by 25.0 Tg C yr-1 if stand age factor was omitted. In most decades, these factors increased forest carbon sinks with the largest of 101.3, 62.9, and 44.0 Tg C yr-1 from 2000 to 2012 contributed by stand age, CO2 concentration and nitrogen deposition, respectively. During 1901-2012, climate change, CO2 concentration, nitrogen deposition and stand age contributed -13.3, 21.4, 15.4 and 25.0 Tg C yr-1 to the averaged carbon sink of China's forests, respectively. Our study also showed diverse regional patterns of forest carbon budget related to the importance of driving factors. Stand age effect was the largest in most regions, but the effects of CO2 concentration and nitrogen deposition were dominant in southern China.

  6. Multi-Cohort Stand Structural Classification: Ground- and LiDAR-based Approaches for Boreal Mixedwood and Black Spruce Forest Types of Northeastern Ontario

    NASA Astrophysics Data System (ADS)

    Kuttner, Benjamin George

    Natural fire return intervals are relatively long in eastern Canadian boreal forests and often allow for the development of stands with multiple, successive cohorts of trees. Multi-cohort forest management (MCM) provides a strategy to maintain such multi-cohort stands that focuses on three broad phases of increasingly complex, post-fire stand development, termed "cohorts", and recommends different silvicultural approaches be applied to emulate different cohort types. Previous research on structural cohort typing has relied upon primarily subjective classification methods; in this thesis, I develop more comprehensive and objective methods for three common boreal mixedwood and black spruce forest types in northeastern Ontario. Additionally, I examine relationships between cohort types and stand age, productivity, and disturbance history and the utility of airborne LiDAR to retrieve ground-based classifications and to extend structural cohort typing from plot- to stand-levels. In both mixedwood and black spruce forest types, stand age and age-related deadwood features varied systematically with cohort classes in support of an age-based interpretation of increasing cohort complexity. However, correlations of stand age with cohort classes were surprisingly weak. Differences in site productivity had a significant effect on the accrual of increasingly complex multi-cohort stand structure in both forest types, especially in black spruce stands. The effects of past harvesting in predictive models of class membership were only significant when considered in isolation of age. As an age-emulation strategy, the three cohort model appeared to be poorly suited to black spruce forests where the accrual of structural complexity appeared to be more a function of site productivity than age. Airborne LiDAR data appear to be particularly useful in recovering plot-based cohort types and extending them to the stand-level. The main gradients of structural variability detected using Li

  7. Statistical properties of mean stand biomass estimators in a LIDAR-based double sampling forest survey design.

    Treesearch

    H.E. Anderson; J. Breidenbach

    2007-01-01

    Airborne laser scanning (LIDAR) can be a valuable tool in double-sampling forest survey designs. LIDAR-derived forest structure metrics are often highly correlated with important forest inventory variables, such as mean stand biomass, and LIDAR-based synthetic regression estimators have the potential to be highly efficient compared to single-stage estimators, which...

  8. Model for multi-stand management based on structural attributes of individual stands

    Treesearch

    G.W. Miller; J. Sullivan

    1997-01-01

    A growing interest in managing forest ecosystems calls for decision models that take into account attribute goals for large forest areas while continuing to recognize the individual stand as a basic unit of forest management. A dynamic, nonlinear forest management model is described that schedules silvicultural treatments for individual stands that are linked by multi-...

  9. Isotopic study of mercury sources and transfer between a freshwater lake and adjacent forest food web.

    PubMed

    Kwon, Sae Yun; Blum, Joel D; Nadelhoffer, Knute J; Timothy Dvonch, J; Tsui, Martin Tsz-Ki

    2015-11-01

    Studies of monomethylmercury (MMHg) sources and biogeochemical pathways have been extensive in aquatic ecosystems, but limited in forest ecosystems. Increasing evidence suggests that there is significant mercury (Hg) exchange between aquatic and forest ecosystems. We use Hg stable isotope ratios (δ(202)Hg and Δ(199)Hg) to investigate the relative importance of MMHg sources and assess Hg transfer pathways between Douglas Lake and adjacent forests located at the University of Michigan Biological Station, USA. We characterize Hg isotopic compositions of basal resources and use linear regression of % MMHg versus δ(202)Hg and Δ(199)Hg to estimate Hg isotope values for inorganic mercury (IHg) and MMHg in the aquatic and adjacent forest food webs. In the aquatic ecosystem, we found that lake sediment represents a mixture of IHg pools deposited via watershed runoff and precipitation. The δ(202)Hg and Δ(199)Hg values estimated for IHg are consistent with other studies that measured forest floor in temperate forests. The Δ(199)Hg value estimated for MMHg in the aquatic food web indicates that MMHg is subjected to ~20% photochemical degradation prior to bioaccumulation. In the forest ecosystem, we found a significant negative relationship between total Hg and δ(202)Hg and Δ(199)Hg of soil collected at multiple distances from the lakeshore and lake sediment. This suggests that IHg input from watershed runoff provides an important Hg transfer pathway between the forest and aquatic ecosystems. We measured Δ(199)Hg values for high trophic level insects and compared these insects at multiple distances perpendicular to the lake shoreline. The Δ(199)Hg values correspond to the % canopy cover suggesting that forest MMHg is subjected to varying extents of photochemical degradation and the extent may be controlled by sunlight. Our study demonstrates that the use of Hg isotopes adds important new insight into the relative importance of MMHg sources and complex Hg transfer

  10. Growth and yield of all-aged Douglas-fir -- western hemlock forest stands: a matrix model with stand diversity effects.

    Treesearch

    Jingjing Liang; Joseph Buonglorno; Robert A. Monserud

    2005-01-01

    A density-dependent matrix model was developed for Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) -- western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest stands in the Pacific Northwest of the United States. The model predicted the number and volume of trees for 4 species groups and 19 diameter classes. The parameters...

  11. Quantifying Components of Soil Respiration and Their Response to Abiotic Factors in Two Typical Subtropical Forest Stands, Southwest China

    PubMed Central

    Yu, Lei; Wang, Yujie; Wang, Yunqi; Sun, Suqi; Liu, Liziyuan

    2015-01-01

    Separating the components of soil respiration and understanding the roles of abiotic factors at a temporal scale among different forest types are critical issues in forest ecosystem carbon cycling. This study quantified the proportions of autotrophic (R A) and heterotrophic (R H) in total soil (R T) respiration using trenching and litter removal. Field studies were conducted in two typical subtropical forest stands (broadleaf and needle leaf mixed forest; bamboo forest) at Jinyun Mountain, near the Three Georges Reservoir in southwest China, during the growing season (Apr.–Sep.) from 2010 to 2012. The effects of air temperature (AT), soil temperature (ST) and soil moisture (SM) at 6cm depth, solar radiation (SR), pH on components of soil respiration were analyzed. Results show that: 1) SR, AT, and ST exhibited a similar temporal trend. The observed abiotic factors showed slight interannual variability for the two forest stands. 2) The contributions of R H and R A to R T for broadleaf and needle leaf mixed forest were 73.25% and 26.75%, respectively, while those for bamboo forest were 89.02% and 10.98%, respectively; soil respiration peaked from June to July. In both stands, CO2 released from the decomposition of soil organic matter (SOM), the strongest contributor to R T, accounted for over 63% of R H. 3) AT and ST were significantly positively correlated with R T and its components (p<0.05), and were major factors affecting soil respiration. 4) Components of soil respiration were significantly different between two forest stands (p<0.05), indicating that vegetation types played a role in soil respiration and its components. PMID:25680112

  12. [Soil quality assessment of forest stand in different plantation esosystems].

    PubMed

    Huang, Yu; Wang, Silong; Feng, Zongwei; Gao, Hong; Wang, Qingkui; Hu, Yalin; Yan, Shaokui

    2004-12-01

    After a clear-cutting of the first generation Cunninghamia lanceolata plantation in 1982, three plantation ecosystems, pure Michelia macclurei stand (PMS), pure Chinese-fir stand (PCS) and their mixed stand, were established in spring 1983, and their effects on soil characteristics were evaluated by measuring some soil physical, chemical, microbiological and biochemical parameters. After 20 years' plantation, all test indices showed differences among different forest management models. Both PMS and MCM had a favorable effect on soil fertility maintenance. Soil quality assessment showed that some soil functions, e.g., water availability, nutrient availability, root suitability and soil quality index were all in a moderate level under the mixed and pure PMS stands, whereas in a relatively lower level under successive PCS stand. The results also showed that there existed close correlations between soil total organic C (TOC), cation exchange capacity (CEC), microbial biomass-C (Cmic) and other soil physical, chemical and biological indices. Therefore, TOC, CEC and Cmic could be used as the indicators in assessing soil quality in this study area. In addition, there were also positive correlations between soil microbial biomass-C and TOC, soil microbial biomass-N and total N, and soil microbial biomass-P and total P in the present study.

  13. Mapping stand-age distribution of Russian forests from satellite data

    NASA Astrophysics Data System (ADS)

    Chen, D.; Loboda, T. V.; Hall, A.; Channan, S.; Weber, C. Y.

    2013-12-01

    Russian boreal forest is a critical component of the global boreal biome as approximately two thirds of the boreal forest is located in Russia. Numerous studies have shown that wildfire and logging have led to extensive modifications of forest cover in the region since 2000. Forest disturbance and subsequent regrowth influences carbon and energy budgets and, in turn, affect climate. Several global and regional satellite-based data products have been developed from coarse (>100m) and moderate (10-100m) resolution imagery to monitor forest cover change over the past decade, record of forest cover change pre-dating year 2000 is very fragmented. Although by using stacks of Landsat images, some information regarding the past disturbances can be obtained, the quantity and locations of such stacks with sufficient number of images are extremely limited, especially in Eastern Siberia. This paper describes a modified method which is built upon previous work to hindcast the disturbance history and map stand-age distribution in the Russian boreal forest. Utilizing data from both Landsat and the Moderate Resolution Imaging Spectroradiometer (MODIS), a wall-to-wall map indicating the estimated age of forest in the Russian boreal forest is created. Our previous work has shown that disturbances can be mapped successfully up to 30 years in the past as the spectral signature of regrowing forests is statistically significantly different from that of mature forests. The presented algorithm ingests 55 multi-temporal stacks of Landsat imagery available over Russian forest before 2001 and processes through a standardized and semi-automated approach to extract training and validation data samples. Landsat data, dating back to 1984, are used to generate maps of forest disturbance using temporal shifts in Disturbance Index through the multi-temporal stack of imagery in selected locations. These maps are then used as reference data to train a decision tree classifier on 50 MODIS

  14. Aggregating pixel-level basal area predictions derived from LiDAR data to industrial forest stands in North-Central Idaho

    Treesearch

    Andrew T. Hudak; Jeffrey S. Evans; Nicholas L. Crookston; Michael J. Falkowski; Brant K. Steigers; Rob Taylor; Halli Hemingway

    2008-01-01

    Stand exams are the principal means by which timber companies monitor and manage their forested lands. Airborne LiDAR surveys sample forest stands at much finer spatial resolution and broader spatial extent than is practical on the ground. In this paper, we developed models that leverage spatially intensive and extensive LiDAR data and a stratified random sample of...

  15. Recent changes in the estimation of standing dead tree biomass and carbon stocks in the U.S. forest inventory

    Treesearch

    Grant M. Domke; Christopher W. Woodall; James E. Smith

    2012-01-01

    Until recently, standing dead tree biomass and carbon (C) has been estimated as a function of live tree growing stock volume in the U.S. Forest Service, Forest Inventory and Analysis (FIA) Program. Traditional estimates of standing dead tree biomass/C attributes were based on merchantability standards that did not reflect density reductions or structural loss due to...

  16. Quercus stellata growth and stand characteristics in the Quercus stellata-Quercus marilandica forest type in the Cross Timbers region of Central Oklahoma

    Treesearch

    James F. Rosson

    1994-01-01

    The author reports a baseline forest survey of Central and West Oklahoma to obtain tree and stand growth rates for harvest sustainability, standing volume estimates for biomass assessments, and stand structure to provide other pertinent data for exploring management options. This report focused on the Quercus stellata-Quercus marilandica forest type in the Cross...

  17. The Central Hardwood Forest: its boundaries and physiographic provinces

    Treesearch

    James S. Fralish

    2003-01-01

    The Central Hardwood Forest (CHF) refers to the area where deciduous hardwood species overwhelmingly, but not exclusively, dominate the stands and cover types that occur as repeating units across the landscape. Transition zones where Central Hardwood species mix with species from adjacent regions identify boundaries of the region. These regions are the Northern...

  18. The Central Hardwood Forest: Its Boundaries and Physiographic Provinces

    Treesearch

    James S. Fralish

    2003-01-01

    The Central Hardwood Forest (CHF) refers to the area where deciduous hardwood species overwhelmingly, but not exclusively, dominate the stands and cover types that occur as repeating units across the landscape. Transition zones where Central Hardwood species mix with species from adjacent regions identify boundaries of the region. These regions are the Northern...

  19. Viewing forests from below: fine root mass declines relative to leaf area in aging lodgepole pine stands.

    PubMed

    Schoonmaker, A S; Lieffers, V J; Landhäusser, S M

    2016-07-01

    In the continued quest to explain the decline in productivity and vigor with aging forest stands, the most poorly studied area relates to root system change in time. This paper measures the wood production, root and leaf area (and mass) in a chronosequence of fire-origin lodgepole pine (Pinus contorta Loudon) stands consisting of four age classes (12, 21, 53, and ≥100 years), each replicated ~ five times. Wood productivity was greatest in the 53-year-old stands and then declined in the ≥100-year-old stands. Growth efficiency, the quantity of wood produced per unit leaf mass, steadily declined with age. Leaf mass and fine root mass plateaued between the 53- and ≥100-year-old stands, but leaf area index actually increased in the older stands. An increase in the leaf area index:fine root area ratio supports the idea that older stand are potentially limited by soil resources. Other factors contributing to slower growth in older stands might be lower soil temperatures and increased self-shading due to the clumped nature of crowns. Collectively, the proportionally greater reduction in fine roots in older stands might be the variable that predisposes these forests to be at a potentially greater risk of stress-induced mortality.

  20. Stem and leaf hydraulics of congeneric tree species from adjacent tropical savanna and forest ecosystems

    Treesearch

    Guang You Hao; William A. Hoffmann; Fabian G. Scholz; Sandra J. Bucci; Frederick C. Meinzer; Augusto C. Franco; Kun Fang Cao; Guillermo Goldstein

    2008-01-01

    Leaf and stem functional traits related to plant water relations were studied for six congeneric species pairs, each composed of one tree species typical of savanna habitats and another typical of adjacent forest habitats, to determine whether there were intrinsic differences in plant hydraulics between these two functional types. Only individuals growing in savanna...

  1. Beetle-killed stands in the South Carolina piedmont: from fuel hazards to regenerating oak forests

    Treesearch

    Aaron D. Stottlemyer; G. Geoff Wang; Thomas A. Waldrop

    2012-01-01

    Impacts of spring prescribed fire, mechanical mastication, and no-treatment (control) on fuels and natural hardwood tree regeneration were examined in beetle-killed stands in the South Carolina Piedmont. Mechanical mastication ground the down and standing dead trees and live vegetation into mulch and deposited it onto the forest floor. The masticated debris layer had...

  2. Comparison of Monterey pine stress in urban and natural forests

    Treesearch

    David J. Nowak; Joe R. McBride

    1991-01-01

    Monterey pine street trees within Carmel, California and its immediate vicinity, as well as forest-grown Monterey pine within adjacent natural stands, were sampled with regard to visual stress characteristics, and various environmental and biological variables. Two stress indices were computed, one hypothesized before data collection was based on relative foliage...

  3. Forest processes from stands to landscapes: exploring model forecast uncertainties using cross-scale model comparison

    Treesearch

    Michael J. Papaik; Andrew Fall; Brian Sturtevant; Daniel Kneeshaw; Christian Messier; Marie-Josee Fortin; Neal Simon

    2010-01-01

    Forest management practices conducted primarily at the stand scale result in simplified forests with regeneration problems and low structural and biological diversity. Landscape models have been used to help design management strategies to address these problems. However, there remains a great deal of uncertainty that the actual management practices result in the...

  4. Using the Forest Vegetation Simulator to reconstruct historical stand conditions in the Colorado Front Range

    Treesearch

    Paula J. Fornwalt; Merrill R. Kaufmann; Laurie S. Huckaby; Jason M. Stoker

    2002-01-01

    Presettlement ponderosa pine/Douglas-fir forests of the Colorado Front Range were open and heterogeneous. Logging, grazing, and fire suppression over past 100 to150 years have altered stand structure by changing diameter distributions and increasing overstory density. In an effort to guide forest restoration toward presettlement conditions, we are currently using the...

  5. Habitat preferences of Boros schneideri (Coleoptera: Boridae) in the natural tree stands of the Białowieża Forest.

    PubMed

    Gutowski, Jerzy M; Sućko, Krzysztof; Zub, Karol; Bohdan, Adam

    2014-01-01

    We analyzed habitat requirements of Boros schneideri (Panzer, 1796) (Coleoptera: Boridae) in the natural forests of the continental biogeographical region, using data collected in the Białowieża Forest. This species has been found on the six host trees, but it preferred dead, standing pine trees, characterized by large diameter, moderately moist and moist phloem but avoided trees in sunny locations. It occurred mostly in mesic and wet coniferous forests. This species demonstrated preferences for old tree stands (over 140-yr old), and its occurrence in younger tree-stand age classes (minimum 31-40-yr old) was not significantly different from random distribution. B. schneideri occupied more frequently locations distant from the forest edge, which were less affected by logging. Considering habitat requirements, character of occurrence, and decreasing number of occupied locations in the whole range of distribution, this species can be treated as relict of primeval forests. © The Author 2014. Published by Oxford University Press on behalf of the Entomological Society of America.

  6. Habitat Preferences of Boros schneideri (Coleoptera: Boridae) in the Natural Tree Stands of the Białowieża Forest

    PubMed Central

    Gutowski, Jerzy M.; Sućko, Krzysztof; Zub, Karol; Bohdan, Adam

    2014-01-01

    Abstract We analyzed habitat requirements of Boros schneideri (Panzer, 1796) (Coleoptera: Boridae) in the natural forests of the continental biogeographical region, using data collected in the Białowieża Forest. This species has been found on the six host trees, but it preferred dead, standing pine trees, characterized by large diameter, moderately moist and moist phloem but avoided trees in sunny locations. It occurred mostly in mesic and wet coniferous forests. This species demonstrated preferences for old tree stands (over 140-yr old), and its occurrence in younger tree-stand age classes (minimum 31–40-yr old) was not significantly different from random distribution. B. schneideri occupied more frequently locations distant from the forest edge, which were less affected by logging. Considering habitat requirements, character of occurrence, and decreasing number of occupied locations in the whole range of distribution, this species can be treated as relict of primeval forests. PMID:25527586

  7. Spatially explicit modeling of 1992-2100 land cover and forest stand age for the conterminous United States

    USGS Publications Warehouse

    Sohl, Terry L.; Sayler, Kristi L.; Bouchard, Michelle; Reker, Ryan R.; Friesz, Aaron M.; Bennett, Stacie L.; Sleeter, Benjamin M.; Sleeter, Rachel R.; Wilson, Tamara; Soulard, Christopher E.; Knuppe, Michelle; Van Hofwegen, Travis

    2014-01-01

    Information on future land-use and land-cover (LULC) change is needed to analyze the impact of LULC change on ecological processes. The U.S. Geological Survey has produced spatially explicit, thematically detailed LULC projections for the conterminous United States. Four qualitative and quantitative scenarios of LULC change were developed, with characteristics consistent with the Intergovernmental Panel on Climate Change (IPCC) Special Report on 5 Emission Scenarios (SRES). The four quantified scenarios (A1B, A2, B1, and B2) served as input to the Forecasting Scenarios of Land-use Change (FORE-SCE) model. Four spatially explicit datasets consistent with scenario storylines were produced for the conterminous United States, with annual LULC maps from 1992 through 2100. The future projections are characterized by a loss of natural land covers in most scenarios, with corresponding expansion of 10 anthropogenic land uses. Along with the loss of natural land covers, remaining natural land covers experience increased fragmentation under most scenarios, with only the B2 scenario remaining relatively stable in both proportion of remaining natural land covers and basic fragmentation measures. Forest stand age was also modeled. By 2100, scenarios and ecoregions with heavy forest cutting have relatively lower mean stand ages compared to those with less 15 forest cutting. Stand ages differ substantially between unprotected and protected forest lands, as well as between different forest classes. The modeled data were compared to the National Land Cover Database (NLCD) and other data sources to assess model characteristics. The consistent, spatially explicit, and thematically detailed LULC projections and the associated forest stand age data layers have been used to analyze LULC impacts on carbon and greenhouse gas fluxes, 20 biodiversity, climate and weather variability, hydrologic change, and other ecological processes.

  8. Abundance of juvenile eastern box turtles in manages forest stands

    Treesearch

    Z. Felix; Y. Wang; H. Czech; C. Schweitzer

    2008-01-01

    Between 2002 and 2005, we used drift fences and artificial pools to sample juvenile eastern box turtles (Terrapene carolina) in northeastern Alabama in forest stands experimentally treated to retain various amounts of overstory trees—clear-cuts and those with 25%–50% and 75%–100% of trees retained.We captured juvenile turtles only in clear-cut and 25%–50% retention...

  9. A Long Term View of Forest Response to Environmental Change: 25 Years of Studying Harvard Forest

    NASA Astrophysics Data System (ADS)

    Munger, J. W.; Wofsy, S. C.; Lindaas, J.; David, F.; David, O.

    2014-12-01

    Forests influence the budgets of greenhouse gases, and understanding how they will respond to environmental change is critical to accurately predicting future GHG trends. The time scale for climate change is long and forest growth is slow, thus very long measurement periods are required to observe meaningful forest response. We established an eddy flux tower within a mixed forest stand dominated by red oak and red maple at the Harvard Forest LTER site in 1989 where CO2, H2O and energy fluxes together with meteorological observations have been measured continuously. An array of plots for biometric measurements was established in 1993. Flux measurement at an adjacent hemlock stand began in 2000. Records of land use and disturbance and vegetation plot data extend back to 1907. The combined suite of measurements merges observations of instantaneous ecosystem responses to environmental forcing with details of vegetation dynamics and forest growth that represent the emergent properties relevant to long-term ecosystem change. Both the deciduous stand and hemlock stand are accumulating biomass. Each has added over 20 Mg-C ha-1 as woody biomass in trees >10cm dbh since 1990, even though the hemlock stand is older. Net carbon exchange shows enhanced uptake in early spring and late fall months in response to warmer temperatures and likely an increase in evergreen foliage at the deciduous site. Net carbon uptake efficiency at the deciduous stand has increased over time as well as indicated by peak NEE under optimum light conditions. The trend is only partly explained by variation in mean leaf area index and cannot be directly attributed to climate response. The combination of longer growing season and increased uptake efficiency yields a general trend of increasing annual NEE (Fig. 1). However, significant excursions in the trend highlight the sensitivity of forest carbon stocks. The pulse of high annual carbon uptake (peak 6 Mg-C ha-1y-1 in 2008) from 2000-2008 is only

  10. Semantic segmentation of forest stands of pure species combining airborne lidar data and very high resolution multispectral imagery

    NASA Astrophysics Data System (ADS)

    Dechesne, Clément; Mallet, Clément; Le Bris, Arnaud; Gouet-Brunet, Valérie

    2017-04-01

    Forest stands are the basic units for forest inventory and mapping. Stands are defined as large forested areas (e.g., ⩾ 2 ha) of homogeneous tree species composition and age. Their accurate delineation is usually performed by human operators through visual analysis of very high resolution (VHR) infra-red images. This task is tedious, highly time consuming, and should be automated for scalability and efficient updating purposes. In this paper, a method based on the fusion of airborne lidar data and VHR multispectral images is proposed for the automatic delineation of forest stands containing one dominant species (purity superior to 75%). This is the key preliminary task for forest land-cover database update. The multispectral images give information about the tree species whereas 3D lidar point clouds provide geometric information on the trees and allow their individual extraction. Multi-modal features are computed, both at pixel and object levels: the objects are individual trees extracted from lidar data. A supervised classification is then performed at the object level in order to coarsely discriminate the existing tree species in each area of interest. The classification results are further processed to obtain homogeneous areas with smooth borders by employing an energy minimum framework, where additional constraints are joined to form the energy function. The experimental results show that the proposed method provides very satisfactory results both in terms of stand labeling and delineation (overall accuracy ranges between 84 % and 99 %).

  11. Tree specific traits vs. stand level characteristics - assessing the source depths of plant water uptake in a mixed forest stand

    NASA Astrophysics Data System (ADS)

    Seeger, Stefan; Brinkmann, Nadine; Kahmen, Ansgar; Weiler, Markus

    2017-04-01

    Due to differences in fine root distributions, physiological root characteristics and plant plasticity, the spatial and temporal characteristics of plant water uptake are expected to vary between different tree species. This has implications on the overall water budget of a forest stand as well as on the drought sensitivity of particular trees. A four-year time series of climate data, soil moisture, and stable water isotopes in soil and tree xylem was used to investigate plant water uptake dynamics of four tree species (beech - Fagus sylvatica, spruce - Picea abies, ash - Fraxinus excelsior and maple - Acer pseudoplatanus) in a mixed forest stand. Modeling with a modified version of the soil hydrological model Hydrus-1D allowed us to simulate continuous time series of stable water isotopes in plant water uptake, which were compared to the measured values in tree xylem water and soil water. We found that different estimated species specific fine root distributions and root water uptake parameters lead to very similar simulated water balances and soil water isotope depth profiles for all four species. According to our simulations, differences in evaporative demand (i.e. LAI) had the biggest influence on water uptake and soil water distributions. Comparing the isotopic signatures of simulated root water uptake and measured xylem water, the simulations for beech were most suited to predict the observed signatures of all four species. This indicates that isolated, tree specific parametrized 1-D simulations are not suited to predict actual water uptake of different trees in a mixed stand. Due to overlapping root spaces dominant trees (in our case beeches with an LAI of around 5.5) may influence the soil water storage below accompanying trees (spruces, ashes and maples with LAIs between 1.8 and 3.1) in a degree that their actual water uptake cannot be predicted with 1-D simulations based on their smaller LAI values. Consequently, for a mixed forest stand the interplay of

  12. Influences of stand structure and fuel treatments on wildfire severity at Blacks Mountain Experimental Forest, northeastern California

    Treesearch

    Julie N. Symons; Dean H. K. Fairbanks; Carl N. Skinner

    2008-01-01

    This study utilizes forest stand structures and fuel profiles to evaluate the influence of different types of silvicultural treatments on fire severity in the Blacks Mountain Experimental Forest (BMEF), located within Lassen National Forest of northeastern California. We compare the severity of fire, assessed based on tree crown and bole scorch on 100 ha experimental...

  13. Four centuries of soil carbon and nitrogen change after stand-replacing fire in a forest landscape in the western Cascade Range of Oregon

    Treesearch

    T. W. Giesen; S. S. Perakis; K. Cromack

    2008-01-01

    Episodic stand-replacing wildfire is a significant disturbance in mesic and moist Douglas-frr (Pseudotsuga menziesii (Mirb.) Franco) forests of the Pacific Northwest. We studied 24 forest stands with known fire histories in the western . Cascade Range in Oregon to evaluate long-tenn impacts of stand-replacing wildfire on carbon (C) and nitrogen (N)...

  14. Determination of fungal diseases, site and stand characteristics in mixed stands in Ilgaz-Yenice forest district, Cankiri, Turkey.

    PubMed

    Oner, Nuri; Dogan, Hasan Huseyin; Ozturk, Celaleddin; Gurer, Meral

    2009-07-01

    Fungal diseases, site and stand characteristics were investigated in Yenice forest sub-district headquarters belonging to Ilgaz forest enterprise. Diseases and wood decaying fungi on fallen and cut tree stumps were determined on scots pine (Pinus sylvestris), crimean pine (P. nigra subsp. nigra varcaramanica), and uludag fir (Abies nordmanniana subsp. bommulleriana). Altitude (m), exposure, slope (%), relief, rate of mixture (%) and anthropogenic effects were noted for 56 sample plots which have various stand compositions. Age, breast height diameter (cm), top height (m), crown and bole quality regeneration quality and development of representative tree species were also recorded into vegetation forms. Yellow witches' broom (Melampsorella caryophyllacearum), which caused drying of uludag fir trees, was determined. Besides, 53 macrofungi species belonging to 3 divisions, 10 orders, 25 families and 36 genera were determined. Some of them cause white and brown decay on living and core wood. The most common parasitic and saprobe fungi are Galerina Ganoderma, Gloeophyllum, Gymnopilus, Hypholoma, Lentinus, Phellinus, Pleurotus, Polyporus and Stereum species in the research area. Trichaptum abietinum is also typical wood decay fungi for living or cut fir trees and it is very common in the research area.

  15. Stand density index as a tool to assess the maximization of forest carbon and biomass

    Treesearch

    Christopher W. Woodall; Anthony W. D’Amato; John B. Bradford; Andrew O. Finley

    2012-01-01

    Given the ability of forests to mitigate greenhouse gas emissions and provide feedstocks to energy utilities, there is an emerging need to assess forest biomass/carbon accretion opportunities over large areas. Techniques for objectively quantifying stand stocking of biomass/carbon are lacking for large areas given the complexity of tree species composition in the U.S....

  16. Agricultural Intensification Exacerbates Spillover Effects on Soil Biogeochemistry in Adjacent Forest Remnants

    PubMed Central

    Didham, Raphael K.; Barker, Gary M.; Bartlam, Scott; Deakin, Elizabeth L.; Denmead, Lisa H.; Fisk, Louise M.; Peters, Jennifer M. R.; Tylianakis, Jason M.; Wright, Hannah R.; Schipper, Louis A.

    2015-01-01

    Land-use intensification is a central element in proposed strategies to address global food security. One rationale for accepting the negative consequences of land-use intensification for farmland biodiversity is that it could ‘spare’ further expansion of agriculture into remaining natural habitats. However, in many regions of the world the only natural habitats that can be spared are fragments within landscapes dominated by agriculture. Therefore, land-sparing arguments hinge on land-use intensification having low spillover effects into adjacent protected areas, otherwise net conservation gains will diminish with increasing intensification. We test, for the first time, whether the degree of spillover from farmland into adjacent natural habitats scales in magnitude with increasing land-use intensity. We identified a continuous land-use intensity gradient across pastoral farming systems in New Zealand (based on 13 components of farmer input and soil biogeochemistry variables), and measured cumulative off-site spillover effects of fertilisers and livestock on soil biogeochemistry in 21 adjacent forest remnants. Ten of 11 measured soil properties differed significantly between remnants and intact-forest reference sites, for both fenced and unfenced remnants, at both edge and interior. For seven variables, the magnitude of effects scaled significantly with magnitude of surrounding land-use intensity, through complex interactions with fencing and edge effects. In particular, total C, total N, δ15N, total P and heavy-metal contaminants of phosphate fertilizers (Cd and U) increased significantly within remnants in response to increasing land-use intensity, and these effects were exacerbated in unfenced relative to fenced remnants. This suggests movement of livestock into surrounding natural habitats is a significant component of agricultural spillover, but pervasive changes in soil biogeochemistry still occur through nutrient spillover channels alone, even in fenced

  17. Tree species diversity and its relationship to stand parameters and geomorphology features in the eastern Black Sea region forests of Turkey.

    PubMed

    Ozcelik, Ramazan; Gul, Altay Ugur; Merganic, Jan; Merganicova, Katarina

    2008-05-01

    We studied the effects of stand parameters (crown closure, basal area, stand volume, age, mean stand diameter number of trees, and heterogeneity index) and geomorphology features (elevation, aspect and slope) on tree species diversity in an example of untreated natural mixed forest stands in the eastern Black Sea region of Turkey. Tree species diversity and basal area heterogeneity in forest ecosystems are quantified using the Shannon-Weaver and Simpson indices. The relationship between tree species diversity basal area heterogeneity stand parameters and geomorphology features are examined using regression analysis. Our work revealed that the relationship between tree species diversity and stand parameters is loose with a correlation coefficient between 0.02 and 0.70. The correlation of basal area heterogeneity with stand parameters fluctuated between 0.004 and 0.77 (R2). According to our results, stands with higher tree species diversity are characterised by higher mean stand diameter number of diameter classes, basal area and lower homogeneity index value. Considering the effect of geomorphology features on tree species or basal area heterogeneity we found that all investigated relationships are loose with R < or = 0.24. A significant correlation was detected only between tree species diversity and aspect. Future work is required to verify the detected trends in behaviour of tree species diversity if it is to estimate from the usual forest stand parameters and topography characteristics.

  18. Forest Stand Canopy Structure Attribute Estimation from High Resolution Digital Airborne Imagery

    Treesearch

    Demetrios Gatziolis

    2006-01-01

    A study of forest stand canopy variable assessment using digital, airborne, multispectral imagery is presented. Variable estimation involves stem density, canopy closure, and mean crown diameter, and it is based on quantification of spatial autocorrelation among pixel digital numbers (DN) using variogram analysis and an alternative, non-parametric approach known as...

  19. Mark-recapture estimation of snag standing rates in northern Arizona mixed-conifer and ponderosa pine forests

    Treesearch

    Joseph L. Ganey; Gary C. White; Jeffrey S. Jenness; Scott C. Vojta

    2015-01-01

    Snags (standing dead trees) are important components of forests that provide resources for numerous species of wildlife and contribute to decay dynamics and other ecological processes. Managers charged with managing populations of snags need information about standing rates of snags and factors influencing those rates, yet such data are limited for ponderosa pine (...

  20. Comparison of riparian and upland forest stand structure and fuel loads in beetle infested watersheds, southern Rocky Mountains

    Treesearch

    Kathleen A. Dwire; Robert Hubbard; Roberto Bazan

    2015-01-01

    Extensive outbreaks of mountain pine beetle (MPB), spruce beetle (SB), and other insects are altering forest stand structure throughout western North America, and thereby contributing to the heterogeneity of fuel distribution. In forested watersheds, conifer-dominated riparian forests frequently occur as narrow linear features in the landscape mosaic and contribute to...

  1. Suggested stocking levels for forest stands in northeastern Oregon and southeastern Washington.

    Treesearch

    P.H. Cochran; J.M. Geist; D.L. Clemens; Rodrick R. Clausnitzer; David C. Powell

    1993-01-01

    Catastrophes and manipulation of stocking levels are important determinants of stand development and the appearance of future forest landscapes. Managers need stocking level guides, particularly for sites incapable of supporting stocking levels presented in normal yield tables. Growth basal area (GBA) has been used by some managers in attempts to assess inherent...

  2. Climate-induced mortality of spruce stands in Belarus

    NASA Astrophysics Data System (ADS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Dvinskaya, Maria L.; Golukov, Alexei S.; Ranson, Kenneth J.

    2015-12-01

    The aim of this work is an analysis of the causes of spruce (Picea abies L.) decline and mortality in Belarus. The analysis was based on forest inventory and Landsat satellite (land cover classification, climate variables (air temperature, precipitation, evaporation, vapor pressure deficit, SPEI drought index)), and GRACE-derived soil moisture estimation (equivalent of water thickness anomalies, EWTA). We found a difference in spatial patterns between dead stands and all stands (i.e., before mortality). Dead stands were located preferentially on relief features with higher water stress risk (i.e., higher elevations, steeper slopes, south and southwestern exposure). Spruce mortality followed a series of repeated droughts between 1990 and 2010. Mortality was negatively correlated with air humidity (r = -0.52), and precipitation (r = -0.57), and positively correlated with the prior year vapor pressure deficit (r = 0.47), and drought increase (r = 0.57). Mortality increased with the increase in occurrence of spring frosts (r = 0.5), and decreased with an increase in winter cloud cover (r = -0.37). Spruce mortality was negatively correlated with snow water accumulation (r = -0.81) and previous year anomalies in water soil content (r = -0.8). Weakened by water stress, spruce stands were attacked by pests and phytopathogens. Overall, spruce mortality in Belarussian forests was caused by drought episodes and drought increase in synergy with pest and phytopathogen attacks. Vast Picea abies mortality in Belarus and adjacent areas of Russia and Eastern Europe is a result of low adaptation of that species to increased drought. This indicates the necessity of spruce replacement by drought-tolerant indigenous (e.g., Pinus sylvestris, Querqus robur) or introduced (e.g., Larix sp. or Pseudotsuga menzieslii) species to obtain sustainable forest growth management.

  3. Climate-Induced Mortality of Spruce Stands in Belarus

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Im, Sergei T.; Dvinskaya, Maria L.; Golukov, Alexei S.; Ranson, Kenneth J.

    2015-01-01

    The aim of this work is an analysis of the causes of spruce (Picea abies L.) decline and mortality in Belarus. The analysis was based on forest inventory and Landsat satellite (land cover classification, climate variables (air temperature, precipitation, evaporation, vapor pressure deficit, SPEI drought index)), and GRACE-derived soil moisture estimation (equivalent of water thickness anomalies, EWTA). We found a difference in spatial patterns between dead stands and all stands (i.e., before mortality). Dead stands were located preferentially on relief features with higher water stress risk (i.e., higher elevations, steeper slopes, south and southwestern exposure). Spruce mortality followed a series of repeated droughts between 1990 and 2010. Mortality was negatively correlated with air humidity (r = -0.52), and precipitation (r = -0.57), and positively correlated with the prior year vapor pressure deficit (r = 0.47), and drought increase (r = 0.57). Mortality increased with the increase in occurrence of spring frosts (r = 0.5), and decreased with an increase in winter cloud cover (r = -0.37). Spruce mortality was negatively correlated with snow water accumulation (r = -0.81) and previous year anomalies in water soil content (r = -0.8). Weakened by water stress, spruce stands were attacked by pests and phytopathogens. Overall, spruce mortality in Belarussian forests was caused by drought episodes and drought increase in synergy with pest and phytopathogen attacks. Vast Picea abies mortality in Belarus and adjacent areas of Russia and Eastern Europe is a result of low adaptation of that species to increased drought. This indicates the necessity of spruce replacement by drought-tolerant indigenous (e.g., Pinus sylvestris, Querqus robur) or introduced (e.g., Larix sp. or Pseudotsuga menzieslii) species to obtain sustainable forest growth management.

  4. Integrating stand and soil properties to understand foliar nutrient dynamics during forest succession following slash-and-burn agriculture in the Bolivian Amazon.

    PubMed

    Broadbent, Eben N; Almeyda Zambrano, Angélica M; Asner, Gregory P; Soriano, Marlene; Field, Christopher B; de Souza, Harrison Ramos; Peña-Claros, Marielos; Adams, Rachel I; Dirzo, Rodolfo; Giles, Larry

    2014-01-01

    Secondary forests cover large areas of the tropics and play an important role in the global carbon cycle. During secondary forest succession, simultaneous changes occur among stand structural attributes, soil properties, and species composition. Most studies classify tree species into categories based on their regeneration requirements. We use a high-resolution secondary forest chronosequence to assign trees to a continuous gradient in species successional status assigned according to their distribution across the chronosequence. Species successional status, not stand age or differences in stand structure or soil properties, was found to be the best predictor of leaf trait variation. Foliar δ(13)C had a significant positive relationship with species successional status, indicating changes in foliar physiology related to growth and competitive strategy, but was not correlated with stand age, whereas soil δ(13)C dynamics were largely constrained by plant species composition. Foliar δ(15)N had a significant negative correlation with both stand age and species successional status, - most likely resulting from a large initial biomass-burning enrichment in soil (15)N and (13)C and not closure of the nitrogen cycle. Foliar %C was neither correlated with stand age nor species successional status but was found to display significant phylogenetic signal. Results from this study are relevant to understanding the dynamics of tree species growth and competition during forest succession and highlight possibilities of, and potentially confounding signals affecting, the utility of leaf traits to understand community and species dynamics during secondary forest succession.

  5. Timber, Browse, and Herbage on Selected Loblolly-Shortleaf Pine-Hardwood Forest Stands

    Treesearch

    Gale L. Wolters; Alton Martin; Warren P. Clary

    1977-01-01

    A thorough vegetation inventory was made on loblolly-shortleaf pine-hardwood stands scheduled by forest industry for clearcutting, site preparation, and planting to pine in north central Louisiana and southern Arkansas. Overstory timber, on the average, contained about equal proportions of softwood and hardwood basal area. Browse plants ranged from 5,500 to over 70,...

  6. Snag densities in old-growth stands on the Gasquet Ranger District, Six Rivers National Forest, California

    Treesearch

    Thomas M. Jimerson

    1989-01-01

    Baseline levels for densities of snags (standing dead trees) wered etermined in undisturbed old-growth stands on the Gasquet Ranger District. Six Riven National Forest, California. Snag species, number, diameter at breast height (d.b.h.), height, cavity type, cavity use, decay class, and snag origin were recorded on 317 plots over a 2-year period. The 2121 snags...

  7. Tree microhabitat structures as indicators of biodiversity in Douglas-fir forests of different stand ages and management histories in the Pacific Northwest, U.S.A.

    Treesearch

    Alexa K. Michel; Susanne Winter

    2009-01-01

    In this study, microhabitat structures in Douglas-fir (Pseudotsuga menziesii) forests were defined and their frequency and abundance in natural stands and stands of varying active management histories and stand ages was compared. Indicator microhabitat structures for natural forests were determined and the relationship of the abundance of...

  8. Spatial pulses of water inputs in deciduous and hemlock forest stands

    NASA Astrophysics Data System (ADS)

    Guswa, A. J.; Mussehl, M.; Pecht, A.; Spence, C.

    2010-12-01

    Trees intercept and redistribute precipitation in time and space. While spatial patterns of throughfall are challenging to link to plant and canopy characteristics, many studies have shown that the spatial patterns persist through time. This persistence leads to wet and dry spots under the trees, creating spatial pulses of moisture that can affect infiltration, transpiration, and biogeochemical processes. In the northeast, the invasive hemlock woolly adelgid poses a significant threat to eastern hemlock (Tsuga canadensis), and replacement of hemlock forests by other species, such as birch, maple, and oak, has the potential to alter throughfall patterns and hydrologic processes. During the summers of 2009 and 2010, we measured throughfall in both hemlock and deciduous plots to assess its spatial distribution and temporal persistence. From 3 June to 25 July 2009, we measured throughfall in one hemlock and one deciduous plot over fourteen events with rainfall totaling 311 mm. From 8 June through 28 July 2010, we measured throughfall in the same two plots plus an additional hemlock stand and a young black birch stand, and rainfall totaled 148 mm over eight events. Averaged over space and time, throughfall was 81% of open precipitation in the hemlock stands, 88% in the mixed deciduous stand, and 100% in the young black birch stand. On an event basis, spatial coefficients of variation are similar among the stands and range from 11% to 49% for rain events greater than 5 mm. With the exception of very light events, coefficients of variation are insensitive to precipitation amount. Spatial patterns of throughfall persist through time, and seasonal coefficients of variation range from 13% to 33%. All stands indicate localized concentrations of water inputs, and there were individual collectors in the deciduous stands that regularly received more than twice the stand-average throughfall.

  9. Can the functional stability of forest ecosystems be evaluated from the spatial analysis of stands? A case study from the Bialowieza Primeval Forest (Poland)

    Treesearch

    Andrzej Bobiec

    2000-01-01

    Variability of external and internal factors entails specific spatial patterns and functional dynamics of communities. The study of the oak-lime-hornbeam (Quercus robur-Tilia cordata-Carpimus) forest in the Bialowieza Primeval Forest supports the concept of silvatic unit, determining the minimal structural area. To find out if the dynamics of a stand...

  10. Determining maximum stand density index in mixed species stands for strategic-scale stocking assessments

    Treesearch

    Chris W. Woodall; Patrick D. Miles; John S. Vissage

    2005-01-01

    Stand density index (SDI), although developed for use in even-aged monocultures, has been used for assessing stand density in large-scale forest inventories containing diverse tree species and size distributions. To improve application of SDI in unevenaged, mixed species stands present in large-scale forest inventories, trends in maximum SDI across diameter classes...

  11. Percent canopy cover and stand structure statistics from the Forest Vegetation Simulator

    Treesearch

    Nicholas L. Crookston; Albert R. Stage

    1999-01-01

    Estimates of percent canopy cover generated by the Forest Vegetation Simulator (FVS) are corrected for crown overlap using an equation presented in this paper. A comparison of the new cover estimate to some others is provided. The cover estimate is one of several describing stand structure. The structure descriptors also include major species, ranges of diameters, tree...

  12. Stand Structural Controls on Evapotranspiration in Native and Invaded Tropical Montane Cloud Forest in Hawai'i

    NASA Astrophysics Data System (ADS)

    Giambelluca, T. W.; Delay, J. K.; Asner, G. P.; Martin, R. E.; Nullet, M. A.; Huang, M.; Mudd, R. G.; Takahashi, M.

    2008-12-01

    Tropical montane cloud forests (TMCFs) in Hawai'i are important zones of water input and stores of critically important native plant and animal species. Invasion by alien tree species threatens these forests and may alter the hydrological services they provide. At two TMCF sites in Hawai'i, one within native Metrosideros polymorpha forest and the other at a site heavily invaded by Psidium cattleianum, we are conducting measurements of stand-level evapotranspiration (ET), transpiration (using sapflow techniques), energy balance, and related processes. Previously presented results showed that ET as a function of available energy was 27% higher at the invaded site than the native site, with the difference rising to 53% during dry- canopy periods. In this presentation, mechanisms for the observed higher ET rate at the invaded site are explored. The difference in measured xylem flow velocities of native and alien trees cannot explain the observed stand level ET difference. Tree basal area is lower at the invaded site than the native site, again contrary to the ET difference. However, the alien trees have much smaller stem diameters, on average, than the native trees, with little or no heartwood. Hence, the cross-sectional xylem area is much greater in the invaded stand, facilitating higher transpiration rates. These results demonstrate the importance of stand structural controls on ET and raise questions about whether higher ET is a transient feature of the succession or a persistent characteristic of invasive trees.

  13. Forest structure and development: implications for forest management

    Treesearch

    Kevin L. O' Hara

    2004-01-01

    A general premise of forest managers is that modern silviculture should be based, in large part, on natural disturbance patterns and species' adaptations to these disturbances. An understanding of forest stand dynamics is therefore a prerequisite to sound forest management. This paper provides a brief overview of forest stand development, stand structures, and...

  14. Longer-term effects of selective thinning on microarthropod communities in a late-successional coniferous forest

    USGS Publications Warehouse

    Peck, R.W.; Niwa, C.G.

    2005-01-01

    Microarthropod densities within late-successional coniferous forests thinned 16-41 yr before sampling were compared with adjacent unthinned stands to identify longer term effects of thinning on this community. Soil and forest floor layers were sampled separately on eight paired sites. Within the forest floor oribatid, mesostigmatid, and to a marginal extent, prostigmatid mites, were reduced in thinned stands compared with unthinned stands. No differences were found for Collembola in the forest floor or for any mite suborder within the soil. Family level examination of mesostigmatid and prostigmatid mites revealed significant differences between stand types for both horizons. At the species level, thinning influenced numerous oribatid mites and Collembola. For oribatid mites, significant or marginally significant differences were found for seven of 15 common species in the forest floor and five of 16 common species in soil. Collembola were affected less, with differences found for one of 11 common species in the forest floor and three of 13 common species in soil. Multivariate analysis of variance and ordination indicated that forest thinning had little influence on the composition of oribatid mite and collembolan communities within either the forest floor or soil. Differences in microclimate or in the accumulation of organic matter on the forest floor were likely most responsible for the observed patterns of abundance. Considering the role that microarthropods play in nutrient cycling, determining the functional response of a wide range of taxa to thinning may be important to effective ecosystem management.

  15. Integrating Stand and Soil Properties to Understand Foliar Nutrient Dynamics during Forest Succession Following Slash-and-Burn Agriculture in the Bolivian Amazon

    PubMed Central

    Broadbent, Eben N.; Almeyda Zambrano, Angélica M.; Asner, Gregory P.; Soriano, Marlene; Field, Christopher B.; de Souza, Harrison Ramos; Peña-Claros, Marielos; Adams, Rachel I.; Dirzo, Rodolfo; Giles, Larry

    2014-01-01

    Secondary forests cover large areas of the tropics and play an important role in the global carbon cycle. During secondary forest succession, simultaneous changes occur among stand structural attributes, soil properties, and species composition. Most studies classify tree species into categories based on their regeneration requirements. We use a high-resolution secondary forest chronosequence to assign trees to a continuous gradient in species successional status assigned according to their distribution across the chronosequence. Species successional status, not stand age or differences in stand structure or soil properties, was found to be the best predictor of leaf trait variation. Foliar δ13C had a significant positive relationship with species successional status, indicating changes in foliar physiology related to growth and competitive strategy, but was not correlated with stand age, whereas soil δ13C dynamics were largely constrained by plant species composition. Foliar δ15N had a significant negative correlation with both stand age and species successional status, – most likely resulting from a large initial biomass-burning enrichment in soil 15N and 13C and not closure of the nitrogen cycle. Foliar %C was neither correlated with stand age nor species successional status but was found to display significant phylogenetic signal. Results from this study are relevant to understanding the dynamics of tree species growth and competition during forest succession and highlight possibilities of, and potentially confounding signals affecting, the utility of leaf traits to understand community and species dynamics during secondary forest succession. PMID:24516525

  16. Effect of long-term understory prescribed burning on standing and down dead woody material in dry upland oak forests

    USGS Publications Warehouse

    Polo, John A.; Hallgren, S.W.; Leslie,, David M.

    2013-01-01

    Dead woody material, long ignored or viewed as a nuisance for forest management, has gained appreciation for its many roles in the forest including wildlife habitat, nutrient storage and cycling, energy for trophic webs, protection of soil, fuel for fire and carbon storage. The growing interest in managing dead woody material has created strong demand for greater understanding of factors controlling amounts and turnover. Prescribed burning, an important management tool, may have strong effects of dead woody material given fire’s capacity to create and consume dead woody material. We determined effects of long-term understory prescribed burning on standing and down woody material in upland oak forests in south-central North America. We hypothesized that as frequency of fire increased in these stands the amount of deadwood would decrease and the fine woody material would decrease more rapidly than coarse woody material. The study was conducted in forests dominated by post oak (Quercus stellata) and blackjack oak (Quercus marilandica) in wildlife management areas where understory prescribed burning had been practiced for over 20 years and the range of burn frequencies was 0 (unburned) fires per decade (FPD) to 4.6 FPD. The amount of deadwood was low compared with more productive forests in southeastern North America. The biomass (24.7 Mg ha-1) and carbon stocks (11.7 Mg ha-1) were distributed among standing dead (22%), coarse woody debris (CWD, dia. > 7.5 cm., 12%), fine woody debris (FWD, dia. < 7.5 cm., 23%), and forest floor (43%). There was no evidence that understory prescribed burning influenced the amount and size distribution of standing and down dead woody material. There were two explanations for the lack of a detectable effect. First, a high incidence of severe weather including ice storms and strong winds that produce large amounts of deadwood intermittently in an irregular pattern across the landscape may preclude detecting a strong effect of understory

  17. Effect of Forest Structural Change on Carbon Storage in a Coastal Metasequoia glyptostroboides Stand

    PubMed Central

    Cheng, Xiangrong; Yu, Mukui; Wu, Tonggui

    2013-01-01

    Forest structural change affects the forest's growth and the carbon storage. Two treatments, thinning (30% thinning intensity) and underplanting plus thinning, are being implemented in a coastal Metasequoia glyptostroboides forest shelterbelt in Eastern China. The vegetation carbon storage significantly increased in the underplanted and thinned treatments compared with that in the unthinned treatment (P < 0.05). The soil and litterfall carbon storage in the underplanted treatment were significantly higher than those in the unthinned treatment (P < 0.05). The total forest ecosystem carbon storage in the underplanted and thinned treatments increased by 35.3% and 26.3%, respectively, compared with that in the unthinned treatment, an increase that mainly came from the growth of vegetation aboveground. Total ecosystem carbon storage showed no significant difference between the underplanted and thinned treatments (P > 0.05). The soil light fraction organic carbon (LFOC) was significantly higher at the 0–15 cm soil layer in the thinned and underplanted stands compared with that in the unthinned stand (P < 0.05). The soil respiration of the underplanted treatment was significantly higher than that of the unthinned treatment only in July (P < 0.05). This study concludes that 30% thinning and underplanting after thinning could be more favorable to carbon sequestration for M. glyptostroboides plantations in the coastal areas of Eastern China. PMID:24187525

  18. Effect of forest structural change on carbon storage in a coastal Metasequoia glyptostroboides stand.

    PubMed

    Cheng, Xiangrong; Yu, Mukui; Wu, Tonggui

    2013-01-01

    Forest structural change affects the forest's growth and the carbon storage. Two treatments, thinning (30% thinning intensity) and underplanting plus thinning, are being implemented in a coastal Metasequoia glyptostroboides forest shelterbelt in Eastern China. The vegetation carbon storage significantly increased in the underplanted and thinned treatments compared with that in the unthinned treatment (P < 0.05). The soil and litterfall carbon storage in the underplanted treatment were significantly higher than those in the unthinned treatment (P < 0.05). The total forest ecosystem carbon storage in the underplanted and thinned treatments increased by 35.3% and 26.3%, respectively, compared with that in the unthinned treatment, an increase that mainly came from the growth of vegetation aboveground. Total ecosystem carbon storage showed no significant difference between the underplanted and thinned treatments (P > 0.05). The soil light fraction organic carbon (LFOC) was significantly higher at the 0-15 cm soil layer in the thinned and underplanted stands compared with that in the unthinned stand (P < 0.05). The soil respiration of the underplanted treatment was significantly higher than that of the unthinned treatment only in July (P < 0.05). This study concludes that 30% thinning and underplanting after thinning could be more favorable to carbon sequestration for M. glyptostroboides plantations in the coastal areas of Eastern China.

  19. Chronic over browsing and biodiversity collapse in a forest understory in Pennsylvania: Results from a 60 year-old deer exclusion plot

    Treesearch

    Chandra Goetsch; Jennifer Wigg; Alejandro A. Royo; Todd Ristau; Walter P. Carson

    2011-01-01

    We evaluated the impact of chronic deer over browsing on the diversity and abundance of understory forbs and shrubs within a forest stand in the Allegheny High Plateau Region of Pennsylvania by comparing vegetation inside a 60-year-old exclosure to vegetation within an adjacent reference site. This is the oldest known exclosure in the Eastern Deciduous Forest. Browsing...

  20. Water and Energy Balances of Loblolly Pine Plantation Forests during a Full Stand Rotation

    NASA Astrophysics Data System (ADS)

    Sun, G.; Mitra, B.; Domec, J. C.; Gavazi, M.; Yang, Y.; Tian, S.; Zietlow, D.; McNulty, S.; King, J.; Noormets, A.

    2017-12-01

    Loblolly pine (Pinus taeda) plantations in the southern U.S. are well recognized for their ecosystem services in supplying clean and stable water and mitigating climate change through carbon sequestration and solar energy partitioning. Since 2004, we have monitored energy, water, and carbon fluxes in a chronosequence of three drained loblolly pine plantations using integrated methods that include eddy covariance, sap flux, watershed hydrometeorology, remote sensing, and process-based simulation modeling. Study sites were located on the eastern North Carolina coastal plain, representing highly productive ecosystems with high groundwater table, and designated in the Ameriflux network as NC1 (0-10 year old), NC2 (12-25 year old) and NC3 (0-3 years old). The 13-year study spanned a wide range of annual precipitation (900-1600 mm/yr) including two exceptionally dry years during 2007-2008. We found that the mature stand (NC2) had higher net radiation (Rn) flux due to its lower albedo (α =0.11-12), compared with the young stands (NC1, NC3) (α=0.15-0.18). Annually about 75%-80% of net radiation was converted to latent heat in the pine plantations. In general, the mature stand had higher latent heat flux (LE) (i.e. evapotranspiration (ET)) rates than the young stands, but ET rates were similar during wet years when the groundwater table was at or near the soil surface. During a historic drought period (i.e., 2007-2008), total stand annual ET exceeded precipitation, but decreased about 30% at NC2 when compared to a normal year (e.g., 2006). Field measurements and remote sensing-based modeling suggested that annual ET rates increased linearly from planting age (about 800 mm) to age 15 (about 1050 mm) and then stabilized as stand leaf area index leveled-off. Over a full stand rotation, approximately 70% (young stand) to 90% (mature stand) of precipitation was returned to the atmosphere through ET. We conclude that both climatic variability and canopy structure controlled the

  1. Estimating stand structure using discrete-return lidar: an example from low density, fire prone ponderosa pine forests

    USGS Publications Warehouse

    Hall, S. A.; Burke, I.C.; Box, D. O.; Kaufmann, M. R.; Stoker, Jason M.

    2005-01-01

    The ponderosa pine forests of the Colorado Front Range, USA, have historically been subjected to wildfires. Recent large burns have increased public interest in fire behavior and effects, and scientific interest in the carbon consequences of wildfires. Remote sensing techniques can provide spatially explicit estimates of stand structural characteristics. Some of these characteristics can be used as inputs to fire behavior models, increasing our understanding of the effect of fuels on fire behavior. Others provide estimates of carbon stocks, allowing us to quantify the carbon consequences of fire. Our objective was to use discrete-return lidar to estimate such variables, including stand height, total aboveground biomass, foliage biomass, basal area, tree density, canopy base height and canopy bulk density. We developed 39 metrics from the lidar data, and used them in limited combinations in regression models, which we fit to field estimates of the stand structural variables. We used an information–theoretic approach to select the best model for each variable, and to select the subset of lidar metrics with most predictive potential. Observed versus predicted values of stand structure variables were highly correlated, with r2 ranging from 57% to 87%. The most parsimonious linear models for the biomass structure variables, based on a restricted dataset, explained between 35% and 58% of the observed variability. Our results provide us with useful estimates of stand height, total aboveground biomass, foliage biomass and basal area. There is promise for using this sensor to estimate tree density, canopy base height and canopy bulk density, though more research is needed to generate robust relationships. We selected 14 lidar metrics that showed the most potential as predictors of stand structure. We suggest that the focus of future lidar studies should broaden to include low density forests, particularly systems where the vertical structure of the canopy is important

  2. Fire-mediated pathways of stand development in Douglas-fir/western hemlock forests of the Pacific Northwest, USA

    Treesearch

    A.J. Tepley; F.J. Swanson; T.A. Spies

    2013-01-01

    Forests dominated by Douglas-fir and western hemlock in the Pacific Northwest of the United States have strongly influenced concepts and policy concerning old-growth forest conservation. Despite the attention to their old-growth characteristics, a tendency remains to view their disturbance ecology in relatively simple terms, emphasizing infrequent, stand-replacing (SR...

  3. Changes in stand structure and composition after restoration treatments in low elevation dry forests of northeastern Oregon.

    Treesearch

    Andrew Youngblood; Kerry L. Metlen; Kent Coe

    2006-01-01

    In many fire-dependent forests in the United States, changes occurring in the last century have resulted in overstory structures, conifer densities, down woody structure and understory plant communities that deviate from those described historically. With these changes, many forests are presumed to be unsustainable. Broad-scale treatments are proposed to promote stand...

  4. Western spruce budworm as related to stand characteristics in the bitterroot national forest

    Treesearch

    Carroll B. Williams; Patrick J. Shea; Gerald S. Walton

    1971-01-01

    Relation of population density to certain stand conditions and damage indicators was analyzed in four drainages on the Bitterroot National Forest of Montana. Western spruce budworm (Choristoneura occidentalis Freeman) populations were strongly related to plot basal area, tree species, and tree crown levels, and also to current and past levels of tree defoliation....

  5. Dynamic anthropogenic edge effects on the distribution and diversity of fungi in fragmented old-growth forests.

    PubMed

    Ruete, Alejandro; Snäll, Tord; Jönsson, Mari

    2016-07-01

    Diversity patterns and dynamics at forest edges are not well understood. We disentangle the relative importance of edge-effect variables on spatio-temporal patterns in species richness and occupancy of deadwood-dwelling fungi in fragmented old-growth forests. We related richness and log occupancy by 10 old-growth forest indicator fungi and by two common fungi to log conditions in natural and anthropogenic edge habitats of 31 old-growth Picea abies forest stands in central Sweden. We compared edge-to-interior gradients (100 m) to the forest interior (beyond 100 m), and we analyzed stand-level changes after 10 yr. Both richness and occupancy of logs by indicator species was negatively related to adjacent young clear-cut edges, but this effect decreased with increasing clear-cut age. The occupancy of logs by indicator species also increased with increasing distance to the natural edges. In contrast, the occupancy of logs by common species was positively related or unrelated to distance to clear-cut edges regardless of the edge age, and this was partly explained by fungal specificity to substrate quality. Stand-level mean richness and mean occupancy of logs did not change for indicator or common species over a decade. By illustrating the importance of spatial and temporal dimensions of edge effects, we extend the general understanding of the distribution and diversity of substrate-confined fungi in fragmented old-growth forests. Our results highlight the importance of longer forest rotation times adjacent to small protected areas and forest set-asides, where it may take more than 50 yr for indicator species richness levels to recover to occupancy levels observed in the forest interior. Also, non-simultaneous clear-cutting of surrounding productive forests in a way that reduces the edge effect over time (i.e., dynamic buffers) may increase the effective core area of small forest set-asides and improve their performance on protecting species of special concern for

  6. Carbon stocks and accumulation rates in Pacific Northwest forests: role of stand age, plant community, and productivity

    Treesearch

    Andrew N. Gray; Thomas R. Whittier; Mark E. Harmon

    2016-01-01

    Forest ecosystems are removing significant amounts of carbon from the atmosphere. Both abiotic resource availability and biotic interactions during forest succession affect C accumulation rates and maximum C stocks. However, the timing and controls on the peak and decline in C accumulation rates as stands age, trees increase in size, and canopy gaps become prevalent...

  7. Contrasts in carbon and nitrogen ecosystem budgets in adjacent Norway spruce and Appalachian hardwood watersheds in the Fernow Experimental Forest, West Virginia

    Treesearch

    Charlene Kelly; Stephen Schoenholtz; Mary Beth Adams

    2011-01-01

    We constructed watershed mass-balance budgets of carbon (C) and nitrogen (N) and measured seasonal net N mineralization in an attempt to account for nearly 40 years of large discrepancies in stream NO3-N export in two adjacent, gauged watersheds at the U.S. Department of Agriculture Forest Service's Fernow Experimental Forest, WV. These...

  8. The Sylview graphical interface to the SYLVAN STAND STRUCTURE model with examples from southern bottomland hardwood forests

    Treesearch

    David R. Larsen; Ian Scott

    2010-01-01

    In the field of forestry, the output of forest growth models provide a wealth of detailed information that can often be difficult to analyze and perceive due to presentation either as plain text summary tables or static stand visualizations. This paper describes the design and implementation of a cross-platform computer application for dynamic and interactive forest...

  9. Ground beetle (Coleoptera, Carabidae) assemblages inhabiting Scots pine stands of Puszcza Piska Forest: six-year responses to a tornado impact.

    PubMed

    Skłodowski, Jarosław; Garbalińska, Paulina

    2011-01-01

    Ground beetle assemblages were studied during 2003-08 in the Pisz Forest by comparing stands disturbed by a tornado to undisturbed control stands. The following exploratory questions were put forward. (1) How do the carabid assemblages change during six years following the tornado impact? (2) Does the carabid assemblage recovery begin during the six first post-tornado years? To assess the state of carabid assemblages we used two indices: the MIB (Mean Individual Biomass) and the SPC (Sum of Progressive Characteristics). Carabid assemblages in the disturbed and in the control stands, as expressed by these two indices, were compared using the length of a regression distance (sample distance in a MIB:SPC coordinate system). A cluster analysis revealed that the assemblages of the disturbed and the control stands were different. The tornado-impacted stands produced lower carabid catch rates, but species richness was significantly higher there than in the control stands. They hosted lower proportions of individuals of European species, of large zoophages, and of forest and brachypterous species, than the control stands. The observed reduction in SPC and MIB, and an increase in the regression distances may indicate that the carabid assemblages had not started to recover from the tornado-caused disturbance. Carabid assemblages apparently responded to the tornado in two steps. Firstly, the first three years were characterized by moderate decreases of index values. Secondly, from the fourth to the sixth year after the tornado, many observed changes became magnified. We did not observe clear signals of the recovery of forest carabid assemblages during the six follow-up years.

  10. Compensating effect of sap velocity for stand density leads to uniform hillslope-scale forest transpiration across a steep valley cross-section

    NASA Astrophysics Data System (ADS)

    Renner, Maik; Hassler, Sibylle; Blume, Theresa; Weiler, Markus; Hildebrandt, Anke; Guderle, Marcus; Schymanski, Stan; Kleidon, Axel

    2016-04-01

    Roberts (1983) found that forest transpiration is relatively uniform across different climatic conditions and suggested that forest transpiration is a conservative process compensating for environmental heterogeneity. Here we test this hypothesis at a steep valley cross-section composed of European Beech in the Attert basin in Luxemburg. We use sapflow, soil moisture, biometric and meteorological data from 6 sites along a transect to estimate site scale transpiration rates. Despite opposing hillslope orientation, different slope angles and forest stand structures, we estimated relatively similar transpiration responses to atmospheric demand and seasonal transpiration totals. This similarity is related to a negative correlation between sap velocity and site-average sapwood area. At the south facing sites with an old, even-aged stand structure and closed canopy layer, we observe significantly lower sap velocities but similar stand-average transpiration rates compared to the north-facing sites with open canopy structure, tall dominant trees and dense understorey. This suggests that plant hydraulic co-ordination allows for flexible responses to environmental conditions leading to similar transpiration rates close to the water and energy limits despite the apparent heterogeneity in exposition, stand density and soil moisture. References Roberts, J. (1983). Forest transpiration: A conservative hydrological process? Journal of Hydrology 66, 133-141.

  11. Logging impact in uneven-aged stands of the Missouri Ozark Forest Ecosystem Project

    Treesearch

    John P. Dwyer

    1999-01-01

    Today, there is keen interest in using alternative silvicultural systems like individual-tree selection, group openings and shelterwood because the general public feels these systems are more acceptable than clearcutting. Consequently, due to repeated entries into forest stands and the fact that residual crop trees have to be carried for a long period of time between...

  12. Fuel buildup and potential fire behavior after stand-replacing fires, logging fire-killed trees and herbicide shrub removal in Sierra Nevada forests

    USGS Publications Warehouse

    McGinnis, Thomas W.; Keeley, Jon E.; Stephens, Scott L.; Roller, Gary B.

    2010-01-01

    Typically, after large stand-replacing fires in mid-elevation Sierra Nevada forests, dense shrub fields occupy sites formerly occupied by mature conifers, until eventually conifers overtop and shade out shrubs. Attempting to reduce fuel loads and expedite forest regeneration in these areas, the USDA Forest Service often disrupts this cycle by the logging of fire-killed trees, replanting of conifers and killing of shrubs. We measured the effects of these treatments on live and dead fuel loads and alien species and modeled potential fire behavior and fire effects on regenerating forests. Sampling occurred in untreated, logged and herbicide-treated stands throughout the Sierra Nevada in four large fire areas 4–21 years after stand-replacing fires. Logging fire-killed trees significantly increased total available dead fuel loads in the short term but did not affect shrub cover, grass and forb cover, alien species cover or alien species richness. Despite the greater available dead fuel loads, fire behavior was not modeled to be different between logged and untreated stands, due to abundant shrub fuels in both logged and untreated stands. In contrast, the herbicide treatment directed at shrubs resulted in extremely low shrub cover, significantly greater alien species richness and significantly greater alien grass and forb cover. Grass and forb cover was strongly correlated with solar radiation on the ground, which may be the primary reason that grass and forb cover was higher in herbicide treated stands with low shrub and tree cover. Repeat burning exacerbated the alien grass problem in some stands. Although modeled surface fire flame lengths and rates of spread were found to be greater in stands dominated by shrubs, compared to low shrub cover conifer plantations, surface fire would still be intense enough to kill most trees, given their small size and low crown heights in the first two decades after planting.

  13. LEAF AREA INDEX (LAI) CHANGE DETECTION ON LOBLOLLY PINE FOREST STANDS WITH COMPLETE UNDERSTORY REMOVAL

    EPA Science Inventory

    The confounding effect of understory vegetation contributions to satellite derived
    estimates of leaf area index (LAI) was investigated on two loblolly pine (Pinus taeda) forest stands located in the southeastern United States. Previous studies have shown that understory can a...

  14. LEAF AREA INDEX (LAI) CHANGE DETECTION ON LOBLOLLY PINE FOREST STANDS WITH COMPLETE UNDERSTORY REMOVAL

    EPA Science Inventory

    The confounding effect of understory vegetation contributions to satellite derived estimates of leaf area index (LAI) was investigated on two loblolly pine forest stands located in the southeastern United States. Previous studies have shown that understory can account from 0-40%...

  15. Estimating canopy cover in forest stands used by Mexican spotted owls: Do stand-exam routines provide estimates comparable to field-based techniques?

    Treesearch

    Joseph L. Ganey; Regis H. Cassidy; William M. Block

    2008-01-01

    Canopy cover has been identified as an important correlate of Mexican spotted owl (Strix occidentalis lucida) habitat, yet management guidelines in a 1995 U.S. Fish and Wildlife Service recovery plan for the Mexican spotted owl did not address canopy cover. These guidelines emphasized parameters included in U.S. Forest Service stand exams, and...

  16. Real-time positioning in logging: Effects of forest stand characteristics, topography, and line-of-sight obstructions on GNSS-RF transponder accuracy and radio signal propagation.

    PubMed

    Zimbelman, Eloise G; Keefe, Robert F

    2018-01-01

    Real-time positioning on mobile devices using global navigation satellite system (GNSS) technology paired with radio frequency (RF) transmission (GNSS-RF) may help to improve safety on logging operations by increasing situational awareness. However, GNSS positional accuracy for ground workers in motion may be reduced by multipath error, satellite signal obstruction, or other factors. Radio propagation of GNSS locations may also be impacted due to line-of-sight (LOS) obstruction in remote, forested areas. The objective of this study was to characterize the effects of forest stand characteristics, topography, and other LOS obstructions on the GNSS accuracy and radio signal propagation quality of multiple Raveon Atlas PT GNSS-RF transponders functioning as a network in a range of forest conditions. Because most previous research with GNSS in forestry has focused on stationary units, we chose to analyze units in motion by evaluating the time-to-signal accuracy of geofence crossings in 21 randomly-selected stands on the University of Idaho Experimental Forest. Specifically, we studied the effects of forest stand characteristics, topography, and LOS obstructions on (1) the odds of missed GNSS-RF signals, (2) the root mean squared error (RMSE) of Atlas PTs, and (3) the time-to-signal accuracy of safety geofence crossings in forested environments. Mixed-effects models used to analyze the data showed that stand characteristics, topography, and obstructions in the LOS affected the odds of missed radio signals while stand variables alone affected RMSE. Both stand characteristics and topography affected the accuracy of geofence alerts.

  17. Real-time positioning in logging: Effects of forest stand characteristics, topography, and line-of-sight obstructions on GNSS-RF transponder accuracy and radio signal propagation

    PubMed Central

    2018-01-01

    Real-time positioning on mobile devices using global navigation satellite system (GNSS) technology paired with radio frequency (RF) transmission (GNSS-RF) may help to improve safety on logging operations by increasing situational awareness. However, GNSS positional accuracy for ground workers in motion may be reduced by multipath error, satellite signal obstruction, or other factors. Radio propagation of GNSS locations may also be impacted due to line-of-sight (LOS) obstruction in remote, forested areas. The objective of this study was to characterize the effects of forest stand characteristics, topography, and other LOS obstructions on the GNSS accuracy and radio signal propagation quality of multiple Raveon Atlas PT GNSS-RF transponders functioning as a network in a range of forest conditions. Because most previous research with GNSS in forestry has focused on stationary units, we chose to analyze units in motion by evaluating the time-to-signal accuracy of geofence crossings in 21 randomly-selected stands on the University of Idaho Experimental Forest. Specifically, we studied the effects of forest stand characteristics, topography, and LOS obstructions on (1) the odds of missed GNSS-RF signals, (2) the root mean squared error (RMSE) of Atlas PTs, and (3) the time-to-signal accuracy of safety geofence crossings in forested environments. Mixed-effects models used to analyze the data showed that stand characteristics, topography, and obstructions in the LOS affected the odds of missed radio signals while stand variables alone affected RMSE. Both stand characteristics and topography affected the accuracy of geofence alerts. PMID:29324794

  18. Uneven-aged silviculture can enhance within stand heterogeneity and beetle diversity.

    PubMed

    Joelsson, Klara; Hjältén, Joakim; Work, Timothy

    2018-01-01

    Uneven-aged silviculture may better maintain species assemblages associated with old-growth forests than clear felling in part due to habitat heterogeneity created by maintaining standing retention strips adjacent to harvest trails. Retention strips and harvest trails created at the time of tree removal will likely have different microclimate and may harbor different assemblages. In some cases, the resultant stand heterogeneity associated with uneven-aged silviculture may be similar to natural small-scale disturbances. For beetles, increased light and temperature as well as potential access to young vegetation and deadwood substrates present in harvset trails may harbor beetle assemblages similar to those found in natural gaps. We sampled saproxylic beetles using flight intercept traps placed in harvest corridors and retention strips in 9 replicated uneven-aged spruce stands in central Sweden. We compared abundance, species richness and composition between harvest corridors and retention strips using generalized linear models, rarefaction, permutational multivariate analysis of variance and indicator species analysis. Canopy openness doubled, mean temperature and variability in daily temperature increased and humidity decreased on harvest trails. Beetle richness and abundance were greater in harvests trails than in retention strips and the beetle species composition differed significantly between habitats. Twenty-five species were associated with harvest trails, including three old-growth specialists such as Agathidium discoideum (Erichson), currently red-listed. We observed only one species, Xylechinus pilosus (Ratzeburg) that strongly favored retention strips. Harvest trails foster both open habitat species and old-growth species while retention strips harbored forest interior specialists. The combination of closed canopy, stratified forest in the retention strips and gap-like conditions on the harvest trails thus increases overall species richness and maintains

  19. Coupled effects of wind-storms and drought on tree mortality across 115 forest stands from the Western Alps and the Jura mountains.

    PubMed

    Csilléry, Katalin; Kunstler, Georges; Courbaud, Benoît; Allard, Denis; Lassègues, Pierre; Haslinger, Klaus; Gardiner, Barry

    2017-12-01

    Damage due to wind-storms and droughts is increasing in many temperate forests, yet little is known about the long-term roles of these key climatic factors in forest dynamics and in the carbon budget. The objective of this study was to estimate individual and coupled effects of droughts and wind-storms on adult tree mortality across a 31-year period in 115 managed, mixed coniferous forest stands from the Western Alps and the Jura mountains. For each stand, yearly mortality was inferred from management records, yearly drought from interpolated fields of monthly temperature, precipitation and soil water holding capacity, and wind-storms from interpolated fields of daily maximum wind speed. We performed a thorough model selection based on a leave-one-out cross-validation of the time series. We compared different critical wind speeds (CWSs) for damage, wind-storm, and stand variables and statistical models. We found that a model including stand characteristics, drought, and storm strength using a CWS of 25 ms -1 performed the best across most stands. Using this best model, we found that drought increased damage risk only in the most southerly forests, and its effect is generally maintained for up to 2 years. Storm strength increased damage risk in all forests in a relatively uniform way. In some stands, we found positive interaction between drought and storm strength most likely because drought weakens trees, and they became more prone to stem breakage under wind-loading. In other stands, we found negative interaction between drought and storm strength, where excessive rain likely leads to soil water saturation making trees more susceptible to overturning in a wind-storm. Our results stress that temporal data are essential to make valid inferences about ecological impacts of disturbance events, and that making inferences about disturbance agents separately can be of limited validity. Under projected future climatic conditions, the direction and strength of these

  20. Rain forest promotes trophic interactions and diversity of trap-nesting Hymenoptera in adjacent agroforestry.

    PubMed

    Klein, Alexandra-Maria; Steffan-Dewenter, Ingolf; Tscharntke, Teja

    2006-03-01

    1. Human alteration of natural ecosystems to agroecosystems continues to accelerate in tropical countries. The resulting world-wide decline of rain forest causes a mosaic landscape, comprising simple and complex agroecosystems and patchily distributed rain forest fragments of different quality. Landscape context and agricultural management can be expected to affect both species diversity and ecosystem services by trophic interactions. 2. In Central Sulawesi, Indonesia, 24 agroforestry systems, differing in the distance to the nearest natural forest (0-1415 m), light intensity (37.5-899.6 W/m(-2)) and number of vascular plant species (7-40 species) were studied. Ten standardized trap nests for bees and wasps, made from reed and knotweed internodes, were exposed in each study site. Occupied nests were collected every month, over a period totalling 15 months. 3. A total of 13,617 brood cells were reared to produce adults of 14 trap-nesting species and 25 natural enemy species, which were mostly parasitoids. The total number of species was affected negatively by increasing distance from forest and increased with light intensity of agroforestry systems. The parasitoids in particular appeared to benefit from nearby forests. Over a 500-m distance, the number of parasitoid species decreased from eight to five, and parasitism rates from 12% to 4%. 4. The results show that diversity and parasitism, as a higher trophic interaction and ecosystem service, are enhanced by (i) improved connectivity of agroecosystems with natural habitats such as agroforestry adjacent to rain forest and (ii) management practices to increase light availability in agroforestry, which also enhances richness of flowering plants in the understorey.

  1. Ground beetle (Coleoptera, Carabidae) assemblages inhabiting Scots pine stands of Puszcza Piska Forest: six-year responses to a tornado impact

    PubMed Central

    Skłodowski, Jarosław; Garbalińska, Paulina

    2011-01-01

    Abstract Ground beetle assemblages were studied during 2003-08 in the Pisz Forest by comparing stands disturbed by a tornado to undisturbed control stands. The following exploratory questions were put forward. (1) How do the carabid assemblages change during six years following the tornado impact? (2) Does the carabid assemblage recovery begin during the six first post-tornado years? To assess the state of carabid assemblages we used two indices: the MIB (Mean Individual Biomass) and the SPC (Sum of Progressive Characteristics). Carabid assemblages in the disturbed and in the control stands, as expressed by these two indices, were compared using the length of a regression distance (sample distance in a MIB:SPC coordinate system). A cluster analysis revealed that the assemblages of the disturbed and the control stands were different. The tornado-impacted stands produced lower carabid catch rates, but species richness was significantly higher there than in the control stands. They hosted lower proportions of individuals of European species, of large zoophages, and of forest and brachypterous species, than the control stands. The observed reduction in SPC and MIB, and an increase in the regression distances may indicate that the carabid assemblages had not started to recover from the tornado-caused disturbance. Carabid assemblages apparently responded to the tornado in two steps. Firstly, the first three years were characterized by moderate decreases of index values. Secondly, from the fourth to the sixth year after the tornado, many observed changes became magnified. We did not observe clear signals of the recovery of forest carabid assemblages during the six follow-up years. PMID:21738422

  2. Assessing stand water use in four coastal wetland forests using sapflow techniques: annual estimates, errors and associated uncertainties

    USGS Publications Warehouse

    Krauss, Ken W.; Duberstein, Jamie A.; Conner, William H.

    2015-01-01

    Forests comprise approximately 37% of the terrestrial land surface and influence global water cycling. However, very little attention has been directed towards understanding environmental impacts on stand water use (S) or in identifying rates of S from specific forested wetlands. Here, we use sapflow techniques to address two separate but linked objectives: (1) determine S in four, hydrologically distinctive South Carolina (USA) wetland forests from 2009–2010 and (2) describe potential error, uncertainty and stand-level variation associated with these assessments. Sapflow measurements were made from a number of tree species for approximately 2–8 months over 2 years to initiate the model, which was applied to canopy trees (DBH > 10–20 cm). We determined that S in three healthy forested wetlands varied from 1.97–3.97 mm day−1 or 355–687 mm year−1 when scaled. In contrast, saltwater intrusion impacted individual tree physiology and size class distributions on a fourth site, which decreased S to 0.61–1.13 mm day−1 or 110–196 mm year−1. The primary sources of error in estimations using sapflow probes would relate to calibration of probes and standardization relative to no flow periods and accounting for accurate sapflow attenuation with radial depth into the sapwood by species and site. Such inherent variation in water use among wetland forest stands makes small differences in S (<200 mm year−1) difficult to detect statistically through modelling, even though small differences may be important to local water cycling. These data also represent some of the first assessments of S from temperate, coastal forested wetlands along the Atlantic coast of the USA.

  3. Land use history and population dynamics of free-standing figs in a maturing forest

    USGS Publications Warehouse

    Albrecht, Larissa; Stallard, Robert F.; Kalko, Elisabeth K.V.

    2017-01-01

    Figs (Ficus sp.) are often considered as keystone resources which strongly influence tropical forest ecosystems. We used long-term tree-census data to track the population dynamics of two abundant free-standing fig species, Ficus insipida and F. yoponensis, on Barro Colorado Island (BCI), a 15.6-km2 island in Lake Gatún, Panama. Vegetation cover on BCI consists of a mosaic of old growth (>400 years) and maturing (about 90–150 year old) secondary rainforest. Locations and conditions of fig trees have been mapped and monitored on BCI for more than 35 years (1973–2011), with a focus on the Lutz Catchment area (25 ha). The original distribution of the fig trees shortly after the construction of the Panama Canal was derived from an aerial photograph from 1927 and was compared with previous land use and forest status. The distribution of both fig species (~850 trees) is restricted to secondary forest. Of the original 119 trees observed in Lutz Catchment in 1973, >70% of F. insipida and >90% of F. yoponensis had died by 2011. Observations in other areas on BCI support the trend of declining free-standing figs. We interpret the decline of these figs on BCI as a natural process within a maturing tropical lowland forest. Senescence of the fig trees appears to have been accelerated by severe droughts such as the strong El Niño event in the year 1982/83. Because figs form such an important food resource for frugivores, this shift in resource availability is likely to have cascading effects on frugivore populations.

  4. Simulation of L-band and HH microwave backscattering from coniferous forest stands - A comparison with SIR-B data

    NASA Technical Reports Server (NTRS)

    Sun, Guo-Qing; Simonett, David S.

    1988-01-01

    SIR-B images of the Mt. Shasta region of northern California are used to evaluate a composite L-band HH backscattering model of coniferous forest stands. It is found that both SIR-B and simulated backscattering coefficients for eight stands studied have similar trends and relations to average tree height and average number of trees per pixel. Also, the dispersion and distribution of simulated backscattering coefficients from each stand broadly match SIR-B data from the same stand. Although the limited quality and quantity of experimental data makes it difficult to draw any strong conclusions, the comparisons indicate that a stand-based L-band HH composite model seems promising for explaining backscattering features.

  5. A stand-alone tree demography and landscape structure module for Earth system models: integration with global forest data

    NASA Astrophysics Data System (ADS)

    Haverd, V.; Smith, B.; Nieradzik, L. P.; Briggs, P. R.

    2014-02-01

    Poorly constrained rates of biomass turnover are a key limitation of Earth system models (ESM). In light of this, we recently proposed a new approach encoded in a model called Populations-Order-Physiology (POP), for the simulation of woody ecosystem stand dynamics, demography and disturbance-mediated heterogeneity. POP is suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any ESM. POP bridges the gap between first generation Dynamic Vegetation Models (DVMs) with simple large-area parameterisations of woody biomass (typically used in current ESMs) and complex second generation DVMs, that explicitly simulate demographic processes and landscape heterogeneity of forests. The key simplification in the POP approach, compared with second-generation DVMs, is to compute physiological processes such as assimilation at grid-scale (with CABLE or a similar land surface model), but to partition the grid-scale biomass increment among age classes defined at sub grid-scale, each subject to its own dynamics. POP was successfully demonstrated along a savanna transect in northern Australia, replicating the effects of strong rainfall and fire disturbance gradients on observed stand productivity and structure. Here, we extend the application of POP to a range of forest types around the globe, employing paired observations of stem biomass and density from forest inventory data to calibrate model parameters governing stand demography and biomass evolution. The calibrated POP model is then coupled to the CABLE land surface model and the combined model (CABLE-POP) is evaluated against leaf-stem allometry observations from forest stands ranging in age from 3 to 200 yr. Results indicate that simulated biomass pools conform well with observed allometry. We conclude that POP represents a preferable alternative to large-area parameterisations of woody biomass turnover, typically used in current ESMs.

  6. Snag recruitment and mortality in a bottomland hardwood forest following partial harvesting: second-year results

    Treesearch

    Brian Roy Lockhart; Philip A. Tappe; David G. Peitz; Christopher A. Watt

    2010-01-01

    Snags are defined simply as standing dead trees. They function as an important component of wildlife habitat. Unfortunately, little information has been gathered regarding snags in bottomland forest ecosystems. We initiated a study to determine the effects of harvesting on the flora and fauna of a bottomland hardwood ecosystem adjacent the Mississippi River in...

  7. Influence of soil thickness on stand characteristics in a Sierra Nevada mixed-conifer forest

    Treesearch

    Marc D. Meyer; Malcolm P. North; Andrew N. Gray; Harold S. J. Zald

    2007-01-01

    Soil thickness can be an important factor influencing vegetation, yet few spatially explicit studies have examined soil horizon thickness and vegetation composition in summer drought forests. We compared seismic and soil penetration measurements of combined A + C and Cr horizon thickness, soil moisture and temperature, and stand variables in a contiguous 4-ha mixed-...

  8. Influence of stocking, site quality, stand age, low-severity canopy disturbance, and forest composition on sub-boreal aspen mixedwood carbon stocks

    USGS Publications Warehouse

    Reinikainen, Michael; D’Amato, Anthony W.; Bradford, John B.; Fraver, Shawn

    2014-01-01

    Low-severity canopy disturbance presumably influences forest carbon dynamics during the course of stand development, yet the topic has received relatively little attention. This is surprising because of the frequent occurrence of such events and the potential for both the severity and frequency of disturbances to increase as a result of climate change. We investigated the impacts of low-severity canopy disturbance and average insect defoliation on forest carbon stocks and rates of carbon sequestration in mature aspen mixedwood forests of varying stand age (ranging from 61 to 85 years), overstory composition, stocking level, and site quality. Stocking level and site quality positively affected the average annual aboveground tree carbon increment (CAAI), while stocking level, site quality, and stand age positively affected tree carbon stocks (CTREE) and total ecosystem carbon stocks (CTOTAL). Cumulative canopy disturbance (DIST) was reconstructed using dendroecological methods over a 29-year period. DIST was negatively and significantly related to soil carbon (CSOIL), and it was negatively, albeit marginally, related to CTOTAL. Minima in the annual aboveground carbon increment of trees (CAI) occurred at sites during defoliation of aspen (Populus tremuloides Michx.) by forest tent caterpillar (Malacosoma disstria Hubner), and minima were more extreme at sites dominated by trembling aspen than sites mixed with conifers. At sites defoliated by forest tent caterpillar in the early 2000s, increased sequestration by the softwood component (Abies balsamea (L.) Mill. and Picea glauca (Moench) Voss) compensated for overall decreases in CAI by 17% on average. These results underscore the importance of accounting for low-severity canopy disturbance events when developing regional forest carbon models and argue for the restoration and maintenance of historically important conifer species within aspen mixedwoods to enhance stand-level resilience to disturbance agents and maintain

  9. Cause-Effect Relations with Regard to Functional and Morphological Humus Characteristics in Mixed Forest Stands

    NASA Astrophysics Data System (ADS)

    Schua, K.; Feger, K.-H.; Wagner, S.; Eisenhauer, D.-R.; Raben, G.

    2009-04-01

    A major argument brought forward when giving reasons for the admixture of deciduous tree species into coniferous forest stands is the amelioration and stabilization of biogeochemical cycles. An ecologically oriented silviculture relies on detailed knowledge about the ecosystem effects of practical measures. Thus, it focuses on the ‘amelioration potential' of a specific tree species with respect to changes of topsoil characteristics in typical monocultural situations. Up-to-now, few data is available concerning the percentages of deciduous species (degree of admixture) or type of admixture (single-tree, small or large groups) required to achieve desired effects, e.g. faster decomposition and incorporation of organic matter in the mineral soil. Thus, the objective of this study is (1) to analyze the impact of admixtures on topsoil properties and processes, and (2) to establish spatial models of such effects. The experiments are conducted in even-aged Norway spruce (Picea abies [L.] KARST.) stands with a variable admixture of Silver birch (Betula pendula Roth) in the Ore Mountains (Saxony, SE Germany). The approach starts with explanation of single-tree-effects and approves in a next step the enlargement to forest stand ("from-point-to-area-approach"). This attempt is expected to provide models with few parameters which can be used to modify the common exclusive growth models.

  10. Using a Standing-Tree Acoustic Tool to Identify Forest Stands for the Production of Mechanically-Graded Lumber

    PubMed Central

    Paradis, Normand; Auty, David; Carter, Peter; Achim, Alexis

    2013-01-01

    This study investigates how the use of a Hitman ST300 acoustic sensor can help identify the best forest stands to be used as supply sources for the production of Machine Stress-Rated (MSR) lumber. Using two piezoelectric sensors, the ST300 measures the velocity of a mechanical wave induced in a standing tree. Measurements were made on 333 black spruce (Picea mariana (Mill.) BSP) trees from the North Shore region, Quebec (Canada) selected across a range of locations and along a chronosequence of elapsed time since the last fire (TSF). Logs were cut from a subsample of 39 trees, and sawn into 77 pieces of 38 mm × 89 mm cross-section before undergoing mechanical testing according to ASTM standard D-4761. A linear regression model was developed to predict the static modulus of elasticity of lumber using tree acoustic velocity and stem diameter at 1.3 m above ground level (R2 = 0.41). Results suggest that, at a regional level, 92% of the black spruce trees meet the requirements of MSR grade 1650Fb-1.5E, whilst 64% and 34% meet the 2100Fb-1.8E and 2400Fb-2.0E, respectively. Mature stands with a TSF < 150 years had 11 and 18% more boards in the latter two categories, respectively, and therefore represented the best supply source for MSR lumber. PMID:23482089

  11. Using a standing-tree acoustic tool to identify forest stands for the production of mechanically-graded lumber.

    PubMed

    Paradis, Normand; Auty, David; Carter, Peter; Achim, Alexis

    2013-03-12

    This study investigates how the use of a Hitman ST300 acoustic sensor can help identify the best forest stands to be used as supply sources for the production of Machine Stress-Rated (MSR) lumber. Using two piezoelectric sensors, the ST300 measures the velocity of a mechanical wave induced in a standing tree. Measurements were made on 333 black spruce (Picea mariana (Mill.) BSP) trees from the North Shore region, Quebec (Canada) selected across a range of locations and along a chronosequence of elapsed time since the last fire (TSF). Logs were cut from a subsample of 39 trees, and sawn into 77 pieces of 38 mm × 89 mm cross-section before undergoing mechanical testing according to ASTM standard D-4761. A linear regression model was developed to predict the static modulus of elasticity of lumber using tree acoustic velocity and stem diameter at 1.3 m above ground level (R2 = 0.41). Results suggest that, at a regional level, 92% of the black spruce trees meet the requirements of MSR grade 1650Fb-1.5E, whilst 64% and 34% meet the 2100Fb-1.8E and 2400Fb-2.0E, respectively. Mature stands with a TSF < 150 years had 11 and 18% more boards in the latter two categories, respectively, and therefore represented the best supply source for MSR lumber.

  12. SAR backscatter from coniferous forest gaps

    NASA Technical Reports Server (NTRS)

    Day, John L.; Davis, Frank W.

    1992-01-01

    A study is in progress comparing Airborne Synthetic Aperture Radar (AIRSAR) backscatter from coniferous forest plots containing gaps to backscatter from adjacent gap-free plots. Issues discussed are how do gaps in the range of 400 to 1600 sq m (approximately 4-14 pixels at intermediate incidence angles) affect forest backscatter statistics and what incidence angles, wavelengths, and polarizations are most sensitive to forest gaps. In order to visualize the slant-range imaging of forest and gaps, a simple conceptual model is used. This strictly qualitative model has led us to hypothesize that forest radar returns at short wavelengths (eg., C-band) and large incidence angles (e.g., 50 deg) should be most affected by the presence of gaps, whereas returns at long wavelengths and small angles should be least affected. Preliminary analysis of 1989 AIRSAR data from forest near Mt. Shasta supports the hypothesis. Current forest backscatter models such as MIMICS and Santa Barbara Discontinuous Canopy Backscatter Model have in several cases correctly predicted backscatter from forest stands based on inputs of measured or estimated forest parameters. These models do not, however, predict within-stand SAR scene texture, or 'intrinsic scene variability' as Ulaby et al. has referred to it. For instance, the Santa Barbara model, which may be the most spatially coupled of the existing models, is not truly spatial. Tree locations within a simulated pixel are distributed according to a Poisson process, as they are in many natural forests, but tree size is unrelated to location, which is not the case in nature. Furthermore, since pixels of a simulated stand are generated independently in the Santa Barbara model, spatial processes larger than one pixel are not modeled. Using a different approach, Oliver modeled scene texture based on an hypothetical forest geometry. His simulated scenes do not agree well with SAR data, perhaps due to the simple geometric model used. Insofar as texture

  13. [Wood transformation in dead-standing trees in the forest-tundra of Central Siberia].

    PubMed

    Mukhortova, L V; Kirdianov, A V; Myglan, V S; Guggenberger, G

    2009-01-01

    Changes in the composition of wood organic matter in dead-standing spruce and larch trees depending on the period after their death have been studied in the north of Central Siberia. The period after tree death has been estimated by means of cross-dating. The results show that changes in the composition of wood organic matter in 63% of cases are contingent on tree species. Wood decomposition in dead-standing trees is accompanied by an increase in the contents of alkali-soluble organic compounds. Lignin oxidation in larch begins approximately 80 years after tree death, whereas its transformation in spruce begins not earlier than after 100 years. In the forest-tundra of Central Siberia, the rate of wood organic matter transformation in dead-standing trees is one to two orders of magnitude lower than in fallen wood, which accounts for their role as a long-term store of carbon and mineral elements in these ecosystems.

  14. Required sample size for monitoring stand dynamics in strict forest reserves: a case study

    Treesearch

    Diego Van Den Meersschaut; Bart De Cuyper; Kris Vandekerkhove; Noel Lust

    2000-01-01

    Stand dynamics in European strict forest reserves are commonly monitored using inventory densities of 5 to 15 percent of the total surface. The assumption that these densities guarantee a representative image of certain parameters is critically analyzed in a case study for the parameters basal area and stem number. The required sample sizes for different accuracy and...

  15. Radiocaesium accumulation in stemwood: integrated approach at the scale of forest stands for contaminated Scots pine in Belarus.

    PubMed

    Goor, François; Thiry, Yves; Delvaux, Bruno

    2007-10-01

    Twenty years after the Chernobyl accident, root uptake from the surface layers of contaminated forest soils plays a major role in radiocaesium ((137)Cs) transfer to the trees and accumulation in perennial compartments, including stemwood. Trustworthy long-term predictions (modelling) of stemwood contamination with (137)Cs should accordingly be based on a reliable picture of this source-sink relationship. Considering the complexity of the processes involved in (137)Cs cycling in forest stands, elementary ratios like transfer factors (TF) were shown to be not very relevant for that purpose. At the tree level, alternatives like the wood immobilisation potential (WIP) have therefore been proposed in order to quantify the current net (137)Cs accumulation in stemwood. Our objective was here to compare WIP values determined for a series of contaminated forest stands in Belarus with the corresponding pools of (137)Cs available in the soil for root uptake. The comparison reveals that both indices are quite proportional, whatever the forest ecosystem features. This corroborates the relevancy of WIP as an indicator of the current (137)Cs root uptake by the trees, which could accordingly help to improve the existing models of (137)Cs cycling and the long-term management of contaminated forest ecosystems.

  16. When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests

    Treesearch

    Brad Oberle; Kiona Ogle; Amy E. Zanne; Christopher W. Woodall

    2018-01-01

    When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests...

  17. Development, succession, and stand dynamics of upland oak forests in the Wisconsin Driftless Area: Implications for oak regeneration and management

    Treesearch

    Megan L. Buchanan; Kurt F. Kipfmueller; Anthony W. D' Amato

    2017-01-01

    Throughout the deciduous forests of the eastern United States, oak (Quercus) regeneration has declined in stands historically dominated by oak species. In the Wisconsin Driftless Area, the level of decline in oak regeneration is variable and influenced by stand structural development, historical disturbance regime, abiotic site characteristics, and...

  18. The effects of forest fragmentation on forest stand attributes

    Treesearch

    Ronald E. McRoberts; Greg C. Liknes

    2002-01-01

    For two study areas in Minnesota, USA, one heavily forested and one sparsely forested, maps of predicted proportion forest area were created using Landsat Thematic Mapper imagery, forest inventory plot data, and a logistic regression model. The maps were used to estimate quantitative indices of forest fragmentation. Correlations between the values of the indices and...

  19. Overland flow generation processes in sub-humid Mediterranean forest stands

    NASA Astrophysics Data System (ADS)

    Ferreira, A. J. D.; Ferreira, C. S. S.; Coelho, C. O. A.; Walsh, R. P. D.; Shakesby, R. A.

    2012-04-01

    Forest soils in north and central Portugal have suffered and continue to suffer major structural changes as a result of forest management techniques, such as clear-felling and as a result of wildfire and rip-ploughing, which is carried out to prepare the ground for planting tree seedlings. In soils that have undergone these changes, the characteristics tend to be different for coniferous plantations, where the root system tends to die when the trees are cut following fire and subsequently may be consumed by fire to form a macropore network, and other types of tree plantations where the root system remains alive and allows regrowth from the sawn tree stumps. Overland flow thresholds decrease sharply as a result of rip-ploughing and forest fires and increase following clear-felling. The time taken for trees to reach maturity after wildfire differs markedly betwen the two main species (Pinus pinaster Aiton and Eucalyptus globulus Labill.) stands. In this paper, overland flow is considered in relation to rainfall, throughfall and throughflow, both in terms of hydrology and hydrochemistry in an attempt to understand overland flow generation mechanisms for a variety of forest land uses (mature pine and eucalyptus, pine seedling regrowth and eucalyptus regrowth from tree stumps, eucalyptus plantations and burned pine). Overland flow generation processes change sharply, even within a single rainfall event, as reflected in the soil hydrological processes and the hydrochemical fingerprints. These effects result from the different contact times for water and soil, which cause differences in the absorption and exhudation processes for the two species

  20. Developments to the Sylvan stand structure model to describe wood quality changes in southern bottomland hardwood forests because of forest management

    Treesearch

    Ian R. Scott

    2009-01-01

    Growth models can produce a wealth of detailed information that is often very difficult to perceive because it is frequently presented either as summary tables, stand view or landscape view visualizations. We have developed new tools for use with the Sylvan model (Larsen 1994) that allow the analysis of wood-quality changes as a consequence of forest management....

  1. Development of a stand density index equation for slash pine stands

    Treesearch

    Paul F. Doruska

    2002-01-01

    Stand density index (SDI) is commonly used as the basis for density management guides for even-aged forest stands. Many tree species follow the same self-thinning trajectory, allowing for the use of stand density index in such guides. Slash pine (Pinus elliottii Englem.) has been shown to depart from the self-thinning trajectory exhibited by other...

  2. Land use history and population dynamics of free-standing figs in a maturing forest

    PubMed Central

    2017-01-01

    Figs (Ficus sp.) are often considered as keystone resources which strongly influence tropical forest ecosystems. We used long-term tree-census data to track the population dynamics of two abundant free-standing fig species, Ficus insipida and F. yoponensis, on Barro Colorado Island (BCI), a 15.6-km2 island in Lake Gatún, Panama. Vegetation cover on BCI consists of a mosaic of old growth (>400 years) and maturing (about 90–150 year old) secondary rainforest. Locations and conditions of fig trees have been mapped and monitored on BCI for more than 35 years (1973–2011), with a focus on the Lutz Catchment area (25 ha). The original distribution of the fig trees shortly after the construction of the Panama Canal was derived from an aerial photograph from 1927 and was compared with previous land use and forest status. The distribution of both fig species (~850 trees) is restricted to secondary forest. Of the original 119 trees observed in Lutz Catchment in 1973, >70% of F. insipida and >90% of F. yoponensis had died by 2011. Observations in other areas on BCI support the trend of declining free-standing figs. We interpret the decline of these figs on BCI as a natural process within a maturing tropical lowland forest. Senescence of the fig trees appears to have been accelerated by severe droughts such as the strong El Niño event in the year 1982/83. Because figs form such an important food resource for frugivores, this shift in resource availability is likely to have cascading effects on frugivore populations. PMID:28542161

  3. Using Lidar and color infrared imagery to successfully measure stand characteristics on the William B. Bankhead National Forest, Alabama

    Treesearch

    Jeffrey Stephens; Luben Dimov; Callie Schweitzer; Wubishet Tadesse

    2008-01-01

    Light detection and ranging (Lidar) and color infrared imagery (CIR) were used to quantify forest structure and to distinguish deciduous from coniferous trees for selected stands on the William B. Bankhead National Forest in Alabama. Lidar bare ground and vegetation point clouds were used to determine tree heights and tree locations. Lidar accuracy was assessed by...

  4. The zero inflation of standing dead tree carbon stocks

    Treesearch

    Christopher W. Woodall; David W. MacFarlane

    2012-01-01

    Given the importance of standing dead trees in numerous forest ecosystem attributes/processes such as carbon (C) stocks, the USDA Forest Service’s Forest Inventory and Analysis (FIA) program began consistent nationwide sampling of standing dead trees in 1999. Modeled estimates of standing dead tree C stocks are currently used as the official C stock estimates for the...

  5. Severity of a mountain pine beetle outbreak across a range of stand conditions in Fraser Experimental Forest, Colorado, United States

    Treesearch

    Anthony G. Vorster; Paul H. Evangelista; Thomas J. Stohlgren; Sunil Kumar; Charles C. Rhoades; Robert M. Hubbard; Antony S. Cheng; Kelly Elder

    2017-01-01

    The recent mountain pine beetle (Dendroctonus ponderosae Hopkins) outbreaks had unprecedented effects on lodgepole pine (Pinus contorta var. latifolia) in western North America. We used data from 165 forest inventory plots to analyze stand conditions that regulate lodgepole pine mortality across a wide range of stand structure and species composition at the Fraser...

  6. Long-term (13-year) effects of repeated prescribed fires on stand structure and tree regeneration in mixed-oak forests

    Treesearch

    Todd F. Hutchinson; Daniel A. Yaussy; Robert P. Long; Joanne Rebbeck; Elaine Kennedy. Sutherland

    2012-01-01

    The survival and growth of oak advance regeneration is often limited by shade-tolerant species that are abundant in the understory of oak stands. Evidence of historic burning has prompted the use of prescribed fire as a tool to improve the competitive status of oak regeneration in mature stands. A primary shortfall of fire effects research in oak forests has been a...

  7. Changing stand structure and regional growth reductions in Georgia's natural pine stands

    Treesearch

    W.A. Bechtold; G.A. Ruark; F.T. Lloyd

    1991-01-01

    Forest Inventory and Analysis (FIA) data indicate reductions in the growth of naturally regenerated pines in Georgia between the two latest measurement periods (1961-1972 vs. 1972-1982). Analysis of Covariance was used to adjust stand-level basal area growth rates for differences between periods in stand age, stand density, site index, mortality, and hardwood...

  8. Challenges in Estimating Evapotranspiration of Young Sparse Stands in a Boreal Forest of Eastern-Canada

    NASA Astrophysics Data System (ADS)

    Hadiwijaya, B.; Nadeau, D.; Pépin, S.

    2017-12-01

    Forest evapotranspiration is the sum of transpiration, evaporation from intercepted rainfall by the canopy and soil evaporation, each component being governed by distinct time scales and mechanisms. Therefore, to develop a simple, yet realistic, model to estimate evapotranspiration over forested areas, field measurements must capture the full chronological sequence of events taking place following rainfall. This becomes a challenge in the case of young sparse forest stands due to large diversity in canopy covers and leaf area indices, which leads to strong spatial variation in intercepted rainfall by the canopy. Unfortunately, very few studies have focused on transition between the dry and wet canopy conditions. The objectives of this study are to investigate each element of rain interception and intercepted water loss, to characterize water loss partitioning processes based on precipitation rate, elapsed time and time-sequence events. To do this, we conducted a summer field campaign at Forêt Montmorency (47°N, 71°W), in southern Québec, Canada, started from early May until late October. The site is characterized by a humid continental climate, with a mean annual precipitation of 1500 mm. The site is located at the boreal forest region, in the balsam for-white birch ecosystem, whose growing season typically extends from May until October. Six measurement plots were established around two micrometeorological towers located in juvenile and sapling forest stands. Five sap flow probes to measure transpiration and a set of rainfall interception instruments (measuring throughfall, free throughfall and stemflow separately) have been deployed on each plot. Initial results presented will include the estimated evapotranspiration rate and soil evaporation measured using eddy covariance method, transpiration rate and high resolution analysis of rainfall interception.

  9. Sustaining northern red oak forests: managing oak from regeneration to canopy dominance in mature stands

    Treesearch

    Daniel C. Dey; Gary W. Miller; John M. Kabrick

    2008-01-01

    Across the range of northern red oak, managers have problems sustaining current stocking of northern red oak in forests. Oak species are adapted to frequent stand disturbances that reduce the abundance of shade tolerant competitors and control fast-growing pioneer species. A widely recommended approach to regenerating northern red oak is to develop relatively large...

  10. Quantifying forest vertical structure to determine bird habitat quality in the Greenbelt Corridor, Denton, TX

    NASA Astrophysics Data System (ADS)

    Matsubayashi, Shiho

    This study presents the integration of light detection and range (LiDAR) and hyperspectral remote sensing to create a three-dimensional bird habitat map in the Greenbelt Corridor of the Elm Fork of the Trinity River. This map permits to examine the relationship between forest stand structure, landscape heterogeneity, and bird community composition. A biannual bird census was conducted at this site during the breeding seasons of 2009 and 2010. Census data combined with the three-dimensional map suggest that local breeding bird abundance, community structure, and spatial distribution patterns are highly influenced by vertical heterogeneity of vegetation surface. For local breeding birds, vertical heterogeneity of canopy surface within stands, connectivity to adjacent forest patches, largest forest patch index, and habitat (vegetation) types proved to be the most influential factors to determine bird community assemblages. Results also highlight the critical role of secondary forests to increase functional connectivity of forest patches. Overall, three-dimensional habitat descriptions derived from integrated LiDAR and hyperspectral data serve as a powerful bird conservation tool that shows how the distribution of bird species relates to forest composition and structure at various scales.

  11. Stand and landscape level effects of a major outbreak of spruce beetles on forest vegetation in the Copper River Basin, Alaska

    USGS Publications Warehouse

    Allen, J.L.; Wesser, S.; Markon, C.J.; Winterberger, K.C.

    2006-01-01

    From 1989 to 2003, a widespread outbreak of spruce beetles (Dendroctonus rufipennis) in the Copper River Basin, Alaska, infested over 275,000 ha of forests in the region. During 1997 and 1998, we measured forest vegetation structure and composition on one hundred and thirty-six 20-m ?? 20-m plots to assess both the immediate stand and landscape level effects of the spruce beetle infestation. A photo-interpreted vegetation and infestation map was produced using color-infrared aerial photography at a scale of 1:40,000. We used linear regression to quantify the effects of the outbreak on forest structure and composition. White spruce (Picea glauca) canopy cover and basal area of medium-to-large trees [???15 cm diameter-at-breast height (1.3 m, dbh)] were reduced linearly as the number of trees attacked by spruce beetles increased. Black spruce (Picea mariana) and small diameter white spruce (<15 cm dbh) were infrequently attacked and killed by spruce beetles. This selective attack of mature white spruce reduced structural complexity of stands to earlier stages of succession and caused mixed tree species stands to lose their white spruce and become more homogeneous in overstory composition. Using the resulting regressions, we developed a transition matrix to describe changes in vegetation types under varying levels of spruce beetle infestations, and applied the model to the vegetation map. Prior to the outbreak, our study area was composed primarily of stands of mixed white and black spruce (29% of area) and pure white spruce (25%). However, the selective attack on white spruce caused many of these stands to transition to black spruce dominated stands (73% increase in area) or shrublands (26% increase in area). The post-infestation landscape was thereby composed of more even distributions of shrubland and white, black, and mixed spruce communities (17-22% of study area). Changes in the cover and composition of understory vegetation were less evident in this study

  12. The legacy of forest harvest and burning on ecosystem carbon storage in the northern midwest, USA

    NASA Astrophysics Data System (ADS)

    Gough, C. M.; Vogel, C. S.; Harrold, K. H.; George, K. D.; Curtis, P. S.

    2005-12-01

    Over 90 % of the forested area in the upper Great Lakes region was harvested by the early 20th century. In many cases, harvests were followed by uncontrolled burns, similar to current patterns of disturbance in many developing countries. While afforestation in the northern midwest has resulted in increased regional carbon (C) storage, the rate of C storage by forests will depend on the severity of prior disturbance and consequent changes in site quality. We were interested in how long the legacy of poor management practices from the early 20th century would be reflected in forest C storage rates. We investigated C cycling and storage following disturbance in mixed deciduous forests of northern lower Michigan, USA. Study plots ranged in age from 6 to 68 yrs and were created following experimental clear-cut harvesting and fire disturbance. Annual C storage was estimated biometrically from measurements of wood, leaf, fine root, and woody debris mass, mass losses to herbivory, soil carbon content, and soil respiration. Maximum annual carbon storage, or net ecosystem production (NEP), in the disturbed stands was 50 % lower than that of adjacent, undisturbed forest. This decrease was caused by a reduction in site quality following disturbance. However, during regrowth the cut and burned forest rapidly became a net C sink, storing 0.86 Mg C ha-1 yr-1 after six yrs. Carbon storage reached a peak of 1.00 Mg C ha-1 yr-1 after 50 yrs and declined to 0.57 Mg C ha-1 yr-1 after 68 yrs. Above- and below-ground net primary production (NPP) averaged 42 and 59 % of total NPP, respectively, with fine root litter production accounting for 57 % of total NPP. Soil heterotrophic respiration was high, ranging from 4.55 Mg C ha-1 yr-1 in the 6-yr-old stand to 5.74 Mg C ha-1 yr-1 in the 50-yr-old stand. Soil C and coarse woody debris pools exhibited a U-shaped trend over time following disturbance. Mineral soil and coarse woody debris pools lost C at a combined annual rate of 1.10 Mg C ha-1

  13. Research on stand management options for reducing fuels and restoring two-aged lodgepole pine communities on the Tenderfoot Creek Experimental Forest

    Treesearch

    Ward McCaughey

    2003-01-01

    Fire-dependent lodgepole pine stands comprise significant acreages of midand upper-elevation forests in the Northern Rockies, providing wood products, wildlife habitat, livestock forage, water, recreational opportunities, and expansive viewsheds. Many lodgepole pine stands are in late-successional stages and at risk to pests and catastrophic-scale fires. Tenderfoot...

  14. Predicting the Probability of Stand Disturbance

    Treesearch

    Gregory A. Reams; Joseph M. McCollum

    1999-01-01

    Forest managers are often interested in identifying and scheduling future stand treatment opportunities. One of the greatest management opportunities is presented following major stand level disturbances that result from natural or anthropogenic forces. Remeasurement data from the Forest Inventory and Analysis (FIA) permanent plot system are used to fit a set of...

  15. OpCost: an open-source system for estimating costs of stand-level forest operations

    Treesearch

    Conor K. Bell; Robert F. Keefe; Jeremy S. Fried

    2017-01-01

    This report describes and documents the OpCost forest operations cost model, a key component of the BioSum analysis framework. OpCost is available in two editions: as a callable module for use with BioSum, and in a stand-alone edition that can be run directly from R. OpCost model logic and assumptions for this open-source tool are explained, references to the...

  16. Method of determining forest production from remotely sensed forest parameters

    DOEpatents

    Corey, J.C.; Mackey, H.E. Jr.

    1987-08-31

    A method of determining forest production entirely from remotely sensed data in which remotely sensed multispectral scanner (MSS) data on forest 5 composition is combined with remotely sensed radar imaging data on forest stand biophysical parameters to provide a measure of forest production. A high correlation has been found to exist between the remotely sensed radar imaging data and on site measurements of biophysical 10 parameters such as stand height, diameter at breast height, total tree height, mean area per tree, and timber stand volume.

  17. Surface fuel treatments in young, regenerating stands affect wildfire severity in a mixed conifer forest, eastside Cascade Range, Washington, USA

    Treesearch

    Christina Lyons-Tinsley; David L. Peterson

    2012-01-01

    Previous studies have debated the flammability of young regenerating stands, especially those in a matrix of mature forest, and no consensus has emerged as to whether young stands are inherently prone to high-severity wildfire. This topic has recently been addressed using spatial imagery, and weak inferences were made given the scale mismatch between the coarse...

  18. Mixed-Forest Species Establishment in a Monodominant Forest in Central Africa: Implications for Tropical Forest Invasibility

    PubMed Central

    Peh, Kelvin S.-H.; Sonké, Bonaventure; Séné, Olivier; Djuikouo, Marie-Noël K.; Nguembou, Charlemagne K.; Taedoumg, Hermann; Begne, Serge K.; Lewis, Simon L.

    2014-01-01

    Background Traits of non-dominant mixed-forest tree species and their synergies for successful co-occurrence in monodominant Gilbertiodendron dewevrei forest have not yet been investigated. Here we compared the tree species diversity of the monodominant forest with its adjacent mixed forest and then determined which fitness proxies and life history traits of the mixed-forest tree species were most associated with successful co-existence in the monodominant forest. Methodology/Principal Findings We sampled all trees (diameter in breast height [dbh]≥10 cm) within 6×1 ha topographically homogenous areas of intact central African forest in SE Cameroon, three independent patches of G. dewevrei-dominated forest and three adjacent areas (450–800 m apart). Monodominant G. dewevrei forest had lower sample-controlled species richness, species density and population density than its adjacent mixed forest in terms of stems with dbh≥10 cm. Analysis of a suite of population-level characteristics, such as relative abundance and geographical distribution, and traits such as wood density, height, diameter at breast height, fruit/seed dispersal mechanism and light requirement–revealed after controlling for phylogeny, species that co-occur with G. dewevrei tend to have higher abundance in adjacent mixed forest, higher wood density and a lower light requirement. Conclusions/Significance Our results suggest that certain traits (wood density and light requirement) and population-level characteristics (relative abundance) may increase the invasibility of a tree species into a tropical closed-canopy system. Such knowledge may assist in the pre-emptive identification of invasive tree species. PMID:24844914

  19. Stand development patterns in southern bottomland hardwoods: Management considerations and research needs

    Treesearch

    Brian R. Lockhart; James S. Meadows; John D. Hodges

    2005-01-01

    Stand development invloves changes in stand structure over time. Knowledge of stand dvelopment patterns is crucial for effective forest managment, especially of southern botomland hardwood forests. These forests contain more than 70 tree species, many of which ahve commercial timber and wildlife habitat value. In this paper, current techniques in stand development...

  20. Overstory tree status following thinning and burning treatments in mixed pine-hardwood stands on the William B. Bankhead National Forest, Alabama

    Treesearch

    Callie Jo Schweitzer; Yong Wang

    2013-01-01

    Prescribed burning and thinning are intermediate stand treatments whose consequences when applied in mixed pine-hardwood stands are unknown. The William B. Bankhead National Forest in northcentral Alabama has undertaken these two options to move unmanaged, 20- to 50-year-old loblolly pine (Pinus taeda L.) plantations towards upland hardwood-dominated...

  1. Southern pine beetle infestations in relation to forest stand conditions, previous thinning, and prescribed burning: evaluation of the Southern Pine Beetle Prevention Program

    Treesearch

    John T. Nowak; James R. Meeker; David R. Coyle; Chris A. Steiner; Cavell Brownie

    2015-01-01

    Since 2003, the Southern Pine Beetle Prevention Program (SPBPP) (a joint effort of the USDA Forest Service and Southern Group of State Foresters) has encouraged and provided cost-share assistance for silvicultural treatments to reduce stand/forest susceptibility to the southern pine beetle (SPB)(Dendroctonus frontalis Zimmermann) in the southeastern United States....

  2. The Missouri Ozark Forest Ecosystem Project: the effects of forest management on the forest ecosystem

    Treesearch

    Brian Brookshire; Carl Hauser

    1993-01-01

    The effects of forest management on non-timber resources are of growing concern to forest managers and the public. While many previous studies have reported effects of stand-level treatments (less than 15 ha) on various stand-level attributes, few studies have attempted to document the influence of forest management on the biotic and abiotic characteristics of entire...

  3. When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests.

    PubMed

    Oberle, Brad; Ogle, Kiona; Zanne, Amy E; Woodall, Christopher W

    2018-01-01

    When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have assessed the relative strength of underlying mechanisms driving snag fall across biomes. Here, we analyze nearly 100,000 repeated snag observations from boreal to subtropical forests across the eastern United States to show that wood decay controls snag fall in ways that could generate previously unrecognized forest-climate feedback. Warmer locations where wood decays quickly had much faster rates of snag fall. The effect of temperature on snag fall was so strong that in a simple forest C model, anticipated warming by mid-century reduced snag C by 22%. Furthermore, species-level differences in wood decay resistance (durability) accurately predicted the timing of snag fall. Differences in half-life for standing dead trees were similar to expected differences in the service lifetimes of wooden structures built from their timber. Strong effects of temperature and wood durability imply future forests where dying trees fall and decay faster than at present, reducing terrestrial C storage and snag-dependent wildlife habitat. These results can improve the representation of forest C cycling and assist forest managers by helping predict when a dead tree may fall.

  4. When a tree falls: Controls on wood decay predict standing dead tree fall and new risks in changing forests

    PubMed Central

    Ogle, Kiona; Zanne, Amy E.; Woodall, Christopher W.

    2018-01-01

    When standing dead trees (snags) fall, they have major impacts on forest ecosystems. Snag fall can redistribute wildlife habitat and impact public safety, while governing important carbon (C) cycle consequences of tree mortality because ground contact accelerates C emissions during deadwood decay. Managing the consequences of altered snag dynamics in changing forests requires predicting when snags fall as wood decay erodes mechanical resistance to breaking forces. Previous studies have pointed to common predictors, such as stem size, degree of decay and species identity, but few have assessed the relative strength of underlying mechanisms driving snag fall across biomes. Here, we analyze nearly 100,000 repeated snag observations from boreal to subtropical forests across the eastern United States to show that wood decay controls snag fall in ways that could generate previously unrecognized forest-climate feedback. Warmer locations where wood decays quickly had much faster rates of snag fall. The effect of temperature on snag fall was so strong that in a simple forest C model, anticipated warming by mid-century reduced snag C by 22%. Furthermore, species-level differences in wood decay resistance (durability) accurately predicted the timing of snag fall. Differences in half-life for standing dead trees were similar to expected differences in the service lifetimes of wooden structures built from their timber. Strong effects of temperature and wood durability imply future forests where dying trees fall and decay faster than at present, reducing terrestrial C storage and snag-dependent wildlife habitat. These results can improve the representation of forest C cycling and assist forest managers by helping predict when a dead tree may fall. PMID:29742158

  5. Salmonberry and salal annual aerial stem production: The maintenance of shrub cover in forest stands

    USGS Publications Warehouse

    Tappeiner, J. C.; Zasada, J.; Huffman, D.; Ganio, L.

    2001-01-01

    Annual sprouting of aerial stems and ramets enables populations of salmonberry (Rubus spectabilis Pursh), salal (Gaultheria shallon Pursh), and probably other forest shrubs to maintain dense covers (>20 000 stems/ha). We studied annual stem production of salmonberry on cut (all stems cut within 15 cm of the ground) and uncut (stems were not treated) plots for 8 years and salal for 5 years in the understories of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), alder, and riparian stands, as well as clearcuts, which are all common stand types in western Oregon. Mean salmonberry stem production on uncut plots ranged from 4.7 stemsA?ma??2A?yeara??1 (95% CI 2.9a??7.4) in alder stands and clearcuts to 1.6 stemsA?ma??2A?yeara??1 (95% CI 1.0a??2.6) in conifer stands. Mean salal production was greater, ranging from 58 stemsA?ma??2A?yeara??1 (95% CI 25a??135) to 8.6 stemsA?ma??2A?yeara??1 (95% CI 3.7a??20.1) on uncut plots in clearcuts and unthinned Douglas-fir stands, respectively. Annual production of both species was somewhat greater on cut plots. Most stems produced in early spring die by December, but enough are recruited to replace mortality of older stems. Stem density was maintained for 8 years for salmonberry and 5 years for salal on both cut and uncut plots. Based on length of rhizomes and bud density we estimate that only 1a??5% of the buds in the rhizomes are needed to support this annual stem production. Although these species sprout vigorously after their aerial stems are killed, disturbance is not necessary for maintaining a dense cover. It appears that, once established, salal, salmonberry, and probably other clonal forest shrubs can maintain a dense cover that can interfere with establishment of trees and other shrubs in canopy gaps or other openings.

  6. Douglas-fir forests in the Cascade Mountains of Oregon and Washington: is the abundance of small mammals related to stand age and moisture?

    USGS Publications Warehouse

    Coen, P.S.; Bury, R.B.; Spies, T.A.

    1988-01-01

    Red tree voles (Arborimus longicaudus) were the only small mammal strongly associated with old-growth forests, whereas vagrant shrews (Sorex vagrans) were most abundant in young forests. Pacific marsh shrews (S. bendirii) were most abundant in wet old-growth forests, but abundance of this species in young (wet) forests needs further study. Clearcuts had a mammalian fauna distinct from young forest stands. Abundance of several species was correlated to habitat features unique to naturally regenerated forests, indicated an urgent need to study the long-term effects of forest management to nongame wildlife.

  7. Rate of value change in Pennsylvania timber stands

    Treesearch

    Owen W. Herrick

    1984-01-01

    Data from remeasured Pennsylvania forest inventory plots revealed that during a 13-year period the compound rate of value change in uncut hardwood forest stands averaged 4.7 percent, and ranged from -5.5 to 18.8 percent. No well-defined means for predicting a stand's rate of value change could be identified, However, some measures of initial stand condition can be...

  8. Changes in Carbon Pool and Stand Structure of a Native Subtropical Mangrove Forest after Inter-Planting with Exotic Species Sonneratia apetala

    PubMed Central

    Lu, Weizhi; Yang, Shengchang; Chen, Luzhen; Wang, Wenqing; Du, Xiaona; Wang, Canmou; Ma, Yan; Lin, Guangxuan; Lin, Guanghui

    2014-01-01

    In this study, we compared stand structure, biomass and soil carbon pools, and litterfall production between a mixed mangrove forest consisting of Aegiceras corniculatum inter-planted with the exotic Sonneratia apetala and a native monospecific forest dominated by A. corniculatum in the intertidal area of Zhanjiang, Guangdong Province, southeast China. The goal of this study was to test the hypothesis that inter-planting fast growing exotic mangrove S. apetala into subtropical native mangrove forests will significantly increase C sequestration. Although the tree heights and basal diameters of S. apetala were significantly higher than those of A. corniculatum, the density of the 12-year-old S. apetala trees in the mixed forest was much smaller than that of A. corniculatum in the monospecific forest. In contrast to several previous studies on S. apetala forests planted directly on mangrove-free mudflats, the mixed mangrove forest showed no significant difference in either standing biomass or soil carbon pools from the native monospecific mangrove forest (p = 0.294 and 0.073, respectively) twelve years after inter-planting with S. apetala. Moreover, carbon cycling was likely speeded up after inter-planting S. apetala due to higher litterfall input and lower C/N ratio. Thus, inter-planting fast-growing S. apetala into native mangrove forest is not an effective way to increase carbon sequestration in this subtropical mangrove forest. Given that exotic plant species may exert negative impact on native mangrove species and related epifauna, this fast-growing mangrove species is not suitable for mangrove plantation projects aiming mainly at enhancing carbon sequestration. PMID:24618793

  9. Changes in carbon pool and stand structure of a native subtropical mangrove forest after inter-planting with exotic species Sonneratia apetala.

    PubMed

    Lu, Weizhi; Yang, Shengchang; Chen, Luzhen; Wang, Wenqing; Du, Xiaona; Wang, Canmou; Ma, Yan; Lin, Guangxuan; Lin, Guanghui

    2014-01-01

    In this study, we compared stand structure, biomass and soil carbon pools, and litterfall production between a mixed mangrove forest consisting of Aegiceras corniculatum inter-planted with the exotic Sonneratia apetala and a native monospecific forest dominated by A. corniculatum in the intertidal area of Zhanjiang, Guangdong Province, southeast China. The goal of this study was to test the hypothesis that inter-planting fast growing exotic mangrove S. apetala into subtropical native mangrove forests will significantly increase C sequestration. Although the tree heights and basal diameters of S. apetala were significantly higher than those of A. corniculatum, the density of the 12-year-old S. apetala trees in the mixed forest was much smaller than that of A. corniculatum in the monospecific forest. In contrast to several previous studies on S. apetala forests planted directly on mangrove-free mudflats, the mixed mangrove forest showed no significant difference in either standing biomass or soil carbon pools from the native monospecific mangrove forest (p = 0.294 and 0.073, respectively) twelve years after inter-planting with S. apetala. Moreover, carbon cycling was likely speeded up after inter-planting S. apetala due to higher litterfall input and lower C/N ratio. Thus, inter-planting fast-growing S. apetala into native mangrove forest is not an effective way to increase carbon sequestration in this subtropical mangrove forest. Given that exotic plant species may exert negative impact on native mangrove species and related epifauna, this fast-growing mangrove species is not suitable for mangrove plantation projects aiming mainly at enhancing carbon sequestration.

  10. Structural and compositional controls on transpiration in 40- and 450-year-old riparian forests in western Oregon, USA.

    PubMed

    Moore, Georgianne W; Bond, Barbara J; Jones, Julia A; Phillips, Nathan; Meinzer, Federick C

    2004-05-01

    Large areas of forests in the Pacific Northwest are being transformed to younger forests, yet little is known about the impact this may have on hydrological cycles. Previous work suggests that old trees use less water per unit leaf area or sapwood area than young mature trees of the same species in similar environments. Do old forests, therefore, use less water than young mature forests in similar environments, or are there other structural or compositional components in the forests that compensate for tree-level differences? We investigated the impacts of tree age, species composition and sapwood basal area on stand-level transpiration in adjacent watersheds at the H.J. Andrews Forest in the western Cascades of Oregon, one containing a young, mature (about 40 years since disturbance) conifer forest and the other an old growth (about 450 years since disturbance) forest. Sap flow measurements were used to evaluate the degree to which differences in age and species composition affect water use. Stand sapwood basal area was evaluated based on a vegetation survey for species, basal area and sapwood basal area in the riparian area of two watersheds. A simple scaling exercise derived from estimated differences in water use as a result of differences in age, species composition and stand sapwood area was used to estimate transpiration from late June through October within the entire riparian area of these watersheds. Transpiration was higher in the young stand because of greater sap flux density (sap flow per unit sapwood area) by age class and species, and greater total stand sapwood area. During the measurement period, mean daily sap flux density was 2.30 times higher in young compared with old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees. Sap flux density was 1.41 times higher in young red alder (Alnus rubra Bong.) compared with young P. menziesii trees, and was 1.45 times higher in old P. menziesii compared with old western hemlock (Tsuga heterophylla (Raf

  11. Standing crop and aboveground biomass partitioning of a dwarf mangrove forest in Taylor River Slough, Florida

    USGS Publications Warehouse

    Coronado-Molina, C.; Day, J.W.; Reyes, E.; Perez, B.C.

    2004-01-01

    The structure and standing crop biomass of a dwarf mangrove forest, located in the salinity transition zone ofTaylor River Slough in the Everglades National Park, were studied. Although the four mangrove species reported for Florida occurred at the study site, dwarf Rhizophora mangle trees dominated the forest. The structural characteristics of the mangrove forest were relatively simple: tree height varied from 0.9 to 1.2 meters, and tree density ranged from 7062 to 23 778 stems haa??1. An allometric relationship was developed to estimate leaf, branch, prop root, and total aboveground biomass of dwarf Rhizophora mangle trees. Total aboveground biomass and their components were best estimated as a power function of the crown area times number of prop roots as an independent variable (Y = B ?? Xa??0.5083). The allometric equation for each tree component was highly significant (p<0.0001), with all r2 values greater than 0.90. The allometric relationship was used to estimate total aboveground biomass that ranged from 7.9 to 23.2 ton haa??1. Rhizophora mangle contributed 85% of total standing crop biomass. Conocarpus erectus, Laguncularia racemosa, and Avicennia germinans contributed the remaining biomass. Average aboveground biomass allocation was 69% for prop roots, 25% for stem and branches, and 6% for leaves. This aboveground biomass partitioning pattern, which gives a major role to prop roots that have the potential to produce an extensive root system, may be an important biological strategy in response to low phosphorus availability and relatively reduced soils that characterize mangrove forests in South Florida.

  12. Variation in Surface and Crown Fire Hazard With Stand Age in Managed Coastal Western Hemlock Zone Forests in Southwestern British Columbia

    Treesearch

    Michael C. Feller; Stefanie L. Pollock

    2006-01-01

    Surface and crown fuels were measured in 186 stands ranging in age from 0 years after clearcutting to old-growth forests > 300 years old in Douglas-fir (Pseudotsuga menziesii) – western hemlock (Tsuga heterophylla) – western redcedar (Thuja plicata) – dominated forests in southwestern British Columbia. Indexes...

  13. Forest attributes and fuel loads of riparian vs. upland stands in mountain pine beetle infested watersheds, southern Rocky Mountains [Chapter 13

    Treesearch

    Kathleen A. Dwire; Roberto A. Bazan; Robert Hubbard

    2015-01-01

    Extensive outbreaks of mountain pine beetle (MPB), spruce beetle (SB), and other insects are altering forest stand structure throughout the Western United States, and thereby increasing the natural heterogeneity of fuel distribution. Riparian forests frequently occur as narrow linear features in the landscape mosaic and can contribute to the spatial complexity of...

  14. Surface albedo in relation to disturbance and early stand dynamics in the boreal forest: Implications for climate models

    NASA Astrophysics Data System (ADS)

    Halim, M. A.; Thomas, S. C.

    2017-12-01

    Surface albedo is the most important biophysical radiative forcing in the boreal forest. General Circulation Model studies have suggested that harvesting of boreal forest has a net cooling effect, in contrast to other terrestrial biomes, by increasing surface albedo. However, albedo estimation in these models has been achieved by simplifying processes governing albedo at a coarse scale (both spatial and temporal). Biophysical processes that determine albedo likely operate on small spatial and temporal scales, requiring more direct estimates of effects of landcover change on net radiation. We established a chronosequence study in post-fire and post-clearcut sites (2013, 2006, 1998), logging data from July 2013 to July 2017 in boreal forest sites in northwestern Ontario, Canada. Each age-class X disturbance had 3 three replicates, matched to 18 permanent circular plots (10-m radius) each with an instrumented tower measuring surface albedo, air and soil temperature, and soil moisture. We also measured leaf area index, species composition and soil organic matter content at each site. BRDF-corrected surface albedo was calculated from daily 30m x 30m reflectance data fused from the MODIS MOD09GA product and Landsat 7 reflectance data. Calculated albedo was verified using ground-based measurements. Results show that fire sites generally had lower (15-25%) albedo than clearcut sites in all seasons. Because of rapid forest regrowth, large perturbations of clearcut harvests on forest albedo started to fade out within a year. Albedo differences between fire and clearcut sites also declined sharply with stand age. Younger stands generally had higher albedo than older stands mainly due to the presence of broadleaf species (for example, Populus tremuloides). In spring, snow melted 10-12 days earlier in recent (2013) clearcut sites compared to closed-canopy sites, causing a sharp reduction in surface albedo in comparison to old clearcut/fire sites (2006 and 1998). Snow melted

  15. [Dynamics of nitrogen and sulfur wet deposition in typical forest stand at different spatial levels in Simian Mountain, mid-subtropical region].

    PubMed

    Sun, Tao; Ma, Ming; Wang, Ding-yong; Huang, Li-xin

    2014-12-01

    In order to investigate the dynamics of nitrogen and sulfur wet deposition in subtropical forest ecosystem, one typical forest stand, evergreen broad-leaved forest, at Simian Mountain located in Chongqing was selected in this research. Based on field monitoring, effects of precipitation, throughfall, litterfall, and groundwater runoff of the typical forest stand on the quality of water of Simian Mountain were investigated from September 2012 to August 2013. Results showed that the rainfall of Simian Mountain was apparently acidic, with average pH of 4.89 and maximum pH of 5.14. The soil, canopies and trunks could increase pH of precipitation, with soils having the maximum increment, followed by the forest canopy. Forest canopy had the function of adsorption and purification of NO3-, NO2- and SO4(2-), and the average entrapment rate was 56.68%, 45.84% and 35.51%, respectively. Moreover, the degradation of litter was probably the main reason for the increase of ion concentrations in the surface litter water. Forest soils could absorb and neutralize NO3-, SO2- and NH4+, and release NO2-. The evergreen broad-leaf forest of mid-subtropical region had the function of interception on NO3-, NO2-, NH4+ and SO4(2-), and the total entrapment rate was 92.86%, 57.86%, 87.24% and 87.25%, respectively, and it had a certain buffering function for the acid rain.

  16. Invasion of European pine stands by a North American forest pathogen and its hybridization with a native interfertile taxon.

    PubMed

    Gonthier, P; Nicolotti, G; Linzer, R; Guglielmo, F; Garbelotto, M

    2007-04-01

    It was recently reported that North American (NA) individuals of the forest pathogen Heterobasidion annosum were found in a single pine stand near Rome, in association with the movement of US troops during World War II. Here, we report on some aspects of the invasion biology of this pathogen in Italian coastal pinewoods, and on its interaction with native (EU) Heterobasidion populations. Spores of Heterobasidion were sampled using woody traps in pine stands along 280 km of coast around Rome. DNA of single-spore colonies was characterized by two sets of nuclear and one set of mitochondrial taxon-specific polymerase chain reaction primers. NA spores were found not only in a single site, but in many locations over a wide geographic area. Invasion occurred at an estimated rate of 1.3 km/year through invasion corridors provided by single trees, and not necessarily by sizable patches of forests. Within the 100-km long range of expansion, the NA taxon was dominant in all pure pine stands. Because abundance of the EU taxon is low and identical among stands within and outside the area invaded by NA individuals, we infer that the exotic population has invaded habitats mostly unoccupied by the native species. Discrepancy between a mitochondrial and a nuclear marker occurred in 3.8% of spores from one site, a mixed oak-pine forest where both taxa were equally represented. Combined phylogenetic analyses on nuclear and mitochondrial loci confirmed these isolates were recombinant. The finding of hybrids indicates that genetic interaction between NA and EU Heterobasidion taxa is occurring as a result of their current sympatry.

  17. Economic analysis of the gypsy moth problem in the northeast: I. applied to commercial forest stands

    Treesearch

    Roger E. McCay; William B. White

    1973-01-01

    A method of calculating immediate and future losses caused by the gypsy moth is presented, using examples of pulpwood and sawtimber stands. Discounting of future losses to evaluate their cost in terms of current expenditure is explained. The effect of infestation on forest management is discussed and a format is given for considering control decisions.

  18. Light intensity related to stand density in mature stands of the western white pine type

    Treesearch

    C. A. Wellner

    1948-01-01

    Where tolerance of forest trees or subordinate vegetation is a factor in management, the forester needs a simple field method of Estimating or forecasting light intensities in forest stands. The following article describes a method developed for estimating light intensity beneath the canopy in western white pine forests which may have application in other types.

  19. Assessing the role of natural disturbance and forest management on dead wood dynamics in mixed-species stands of central Maine, USA

    Treesearch

    Joshua J. Puhlick; Aaron R. Weiskittel; Shawn Fraver; Matthew B. Russell; Laura S. Kenefic

    2016-01-01

    Dead wood pools are strongly influenced by natural disturbance events, stand development processes, and forest management activities. However, the relative importance of these influences can vary over time. In this study, we evaluate the role of these factors on dead wood biomass pools across several forest management alternatives after 60 years of treatment on the...

  20. The impact of pollutants from a major northern highway on an adjacent hardwood forest.

    PubMed

    Watmough, S A; Rabinowitz, T; Baker, S

    2017-02-01

    Emissions of pollutants from highways can exert multiple stresses on adjacent ecosystems. In this study air concentrations of NO 2 and throughfall deposition of inorganic N (NO 3 - and NH 4 + ), SO 4 2- , Cl - , base cations and several metals were measured in all four seasons along a 1.5km hardwood forest gradient extending away from a major highway (Highway 401) in southern Ontario, Canada. Soil and lichen chemistry and herbaceous plant and epiphytic lichen species composition were measured within the hardwood forest to evaluate impacts of these pollutants. Air concentrations of NO 2 and deposition of inorganic N, Cl - , base cations and Cu and Zn in throughfall were significantly elevated within 100m of the road compared with the more distant sites. Concentrations of several pollutants including N (and δ 15 N), Na + , Al and Fe in epiphytic lichen tissue decreased with distance from the highway, and epiphytic lichen richness was lower at sites within 100m of the road. Despite high throughfall inputs of >15kgNha -1 y -1 and 100kgNa + ha -1 y -1 within 33m of the highway, for example, there was no significant difference in soil chemistry amongst sites. Plant community composition at sites within 80m of the highway differed from sites located further from the road, but it is unclear whether differences were due to highway emissions or were a result of natural forest edge effects. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. Long-term outcome after adjacent two-level anterior cervical discectomy and fusion using stand-alone plasmaphore-covered titanium cages.

    PubMed

    Marbacher, Serge; Hidalgo-Staub, Teresa; Kienzler, Jenny; Wüergler-Hauri, Carola; Landolt, Hans; Fandino, Javier

    2015-05-01

    Reports on long-term outcome of stand-alone contiguous two-level anterior cervical discectomy and fusion (ACDF) using stand-alone Plasmaphore-coated titanium cages (PCTCs) are rare, and data on follow-ups > 3 years are missing. To evaluate the long-term outcome of adjacent two-level microsurgical ACDF using stand-alone PCTC. A total of 33 consecutive patients presented with cervical degenerative disc disease (DDD) underwent contiguous two-level ACDF. Clinical long-term evaluation (mean: 61 ± 14 months) included documentation of neurologic deficits (motor deficits, sensory deficits, reflex status, and gait disturbance), neck pain, and radicular pain. Functional outcome was measured using the Odom criteria, patient-perceived outcome, and evaluation of work status. Radiographs were evaluated to assess intervertebral disc height, subsidence, level of fusion, sagittal balance, and implant position. Surgery was performed at levels C5-C6 and C6-C7 in 30 patients and at C4-C5 and C5-C6 in 3 (mean age: 50.1 ± 7.7 years). Symptoms and neurologic deficits improved as follows: neurologic deficits (pre: 100%; post: 36%), radicular pain (pre: 85%; post: 15%), and neck pain (pre: 94%; post: 33%). Excellent and good functional and subjective outcome was noted in 75%. Cage subsidence was found to be more prominent in the lower (52%) than the upper (36%) mobile cervical segment. Two-level fusion was documented in most patients (n = 29 [88%]). Kyphotic deformity occurred in two cases (n = 2 [6%]). Stand-alone contiguous two-level ACDF using PCPT proved to be effective, yielding good long-term clinical and functional outcomes. The relatively high rate of subsidence did not affect the good clinical and functional long-term outcome. Georg Thieme Verlag KG Stuttgart · New York.

  2. Forests

    Treesearch

    Louis R. Iverson; Mark W. Schwartz

    1994-01-01

    Originally diminished by development, forests are coming back: forest biomass is accumulating. Forests are repositories for many threatened species. Even with increased standing timber, however, biodiversity is threatened by increased forest fragmentation and by exotic species.

  3. Developing a stand hazard index for oak decline in upland Oak forests of the Ozark Highlands, Missouri

    Treesearch

    Fan Zhaofei; Fan Xiuli; Martin A. Spetich; Stephen R. Shifley; W. Keith Moser; Randy G. Jensen; John M. Kabrick

    2011-01-01

    Black oak (Quercus velutina Lam.) and scarlet oak (Quercus coccinea Muenchh.)--two major components (44% of total stand basal area) of upland oak forests--are suffering severe decline and mortality in the Ozark Highlands, Missouri. However, factors influencing their survival (mortality) are not well understood. In this study we...

  4. A comparison of landscape fuel treatment strategies to mitigate wildland fire risk in the urban interface and preserve old forest structure

    Treesearch

    Alan Ager; Nicole Vaillant

    2010-01-01

    We simulated fuel reduction treatments on a 16,000-ha study area in Oregon, US, to examine tradeoffs between placing fuel treatments near residential structures within an urban interface, versus treating stands in the adjacent wildlands to meet forest health and ecological restoration goals. The treatment strategies were evaluated by simulating 10,000 wildfires with...

  5. Habitat use by forest bats in South Carolina in relation to local, stand, and landscape characteristics

    Treesearch

    Susan C. Loeb; Joy M. O' Keefe

    2006-01-01

    Knowledge and understanding of bat habitat associations and the responses of bats to forest management are critical for effective bat conservation and management. Few studies have been conducted on bat habitat use in the southeast, despite the high number of endangered and sensitive species in the region. Our objective was to identify important local, stand, and...

  6. Stand level impacts of Ips and Dendroctonus bark beetles in pine forest types of northern Arizona

    Treesearch

    Joel McMillin; John Anhold; Jose Negron

    2008-01-01

    (Please note, this is an extended abstract only) Extensive tree mortality occurred in ponderosa pine forests and pinon-juniper woodlands of Arizona from 2001-2004. This mortality has been attributed to a combination of an extensive drought, overstocked stands of pine, and increased bark beetle populations. A complex of Ips and Dendroctonus species worked in concert to...

  7. Comparing field- and model-based standing dead tree carbon stock estimates across forests of the US

    Treesearch

    Chistopher W. Woodall; Grant M. Domke; David W. MacFarlane; Christopher M. Oswalt

    2012-01-01

    As signatories to the United Nation Framework Convention on Climate Change, the US has been estimating standing dead tree (SDT) carbon (C) stocks using a model based on live tree attributes. The USDA Forest Service began sampling SDTs nationwide in 1999. With comprehensive field data now available, the objective of this study was to compare field- and model-based...

  8. Stem and leaf hydraulics of congeneric tree species from adjacent tropical savanna and forest ecosystems.

    PubMed

    Hao, Guang-You; Hoffmann, William A; Scholz, Fabian G; Bucci, Sandra J; Meinzer, Frederick C; Franco, Augusto C; Cao, Kun-Fang; Goldstein, Guillermo

    2008-03-01

    Leaf and stem functional traits related to plant water relations were studied for six congeneric species pairs, each composed of one tree species typical of savanna habitats and another typical of adjacent forest habitats, to determine whether there were intrinsic differences in plant hydraulics between these two functional types. Only individuals growing in savanna habitats were studied. Most stem traits, including wood density, the xylem water potential at 50% loss of hydraulic conductivity, sapwood area specific conductivity, and leaf area specific conductivity did not differ significantly between savanna and forest species. However, maximum leaf hydraulic conductance (K (leaf)) and leaf capacitance tended to be higher in savanna species. Predawn leaf water potential and leaf mass per area were also higher in savanna species in all congeneric pairs. Hydraulic vulnerability curves of stems and leaves indicated that leaves were more vulnerable to drought-induced cavitation than terminal branches regardless of genus. The midday K (leaf) values estimated from leaf vulnerability curves were very low implying that daily embolism repair may occur in leaves. An electric circuit analog model predicted that, compared to forest species, savanna species took longer for their leaf water potentials to drop from predawn values to values corresponding to 50% loss of K (leaf) or to the turgor loss points, suggesting that savanna species were more buffered from changes in leaf water potential. The results of this study suggest that the relative success of savanna over forest species in savanna is related in part to their ability to cope with drought, which is determined more by leaf than by stem hydraulic traits. Variation among genera accounted for a large proportion of the total variance in most traits, which indicates that, despite different selective pressures in savanna and forest habitats, phylogeny has a stronger effect than habitat in determining most hydraulic traits.

  9. Selection of roosting habitat by forest bats in a diverse forested landscape

    Treesearch

    Roger W. Perry; Ronald E. Thill; David M. Leslie

    2007-01-01

    Many studies of roost selection by forest-dwelling bats have concentrated on microhabitat surrounding roosts without providing forest stand level preferences of bats; thus, those studies have provided only part of the information needed by managers. We evaluated diurnal summer roost selection by the bat community at the forest-stand level in a diversely forested...

  10. Environmental influences on tree and stand increment, proceedings of the mensuration, growth and yield instruments and methods in forest mensuration workshop

    Treesearch

    Dale S. Solomon; Thomas B. Brann

    1986-01-01

    An international conference on Environmental Influences on Tree and Stand Increment was held at the University of New Hampshire, Durham, New Hampshire, USA between September 23 and 27, 1985. The meeting included recommendations from a previous I.U.F.R.O. meeting in Vienna, Austria. Demands for forest resources are increasing but the forest land base is constantly...

  11. Species composition of developing Central Appalachian hardwood stands following clearcutting

    Treesearch

    Lance A. Vickers; Thomas Fox

    2015-01-01

    This study examined the species composition of 47 paired stands on submesic sites on the Appalachian Plateau of West Virginia. Paired stands consisted of a mature stand adjacent to a young clearcut that was

  12. N-15 tracing helps explaining N leaching losses from contrasting forest ecosystems

    NASA Astrophysics Data System (ADS)

    Staelens, J.; Rütting, T.; Huygens, D.; Müller, C.; Verheyen, K.; Boeckx, P.

    2009-04-01

    Despite chronically enhanced nitrogen (N) deposition to forest ecosystems in Europe and NE America, considerable N retention by forests has been observed, reducing N leaching losses. Organic and mineral soil layers typically immobilize more N than the aboveground biomass, but it is unclear which factors determine N retention in forest ecoystems. However, this knowledge is crucial to assess the impact of changing anthropogenic N emissions on future N cycling and N loss of forests. For coniferous and deciduous forest stands at comparable sites, it is known that both N deposition onto the forest floor as well as N loss by leaching below the rooting zone are significantly higher in coniferous stands. In addition, the N loss in coniferous stands is often more enhanced than can be explained by the higher N input only. This suggests lower N retention by coniferous stands, and may be related to differences in litter and soil characteristics, microbial activity, and N uptake by plant roots. To test this hypothesis, we studied the effect of forest type on N retention using 15N tracing techniques: a field tracer experiment and a combination of in situ isotope pool dilution and a tracing model. The N dynamics were examined for two adjacent forest stands (pedunculate oak (Quercus robur L.) and Scots pine (Pinus sylvestris L.)) on a well-drained sandy soil and with a similar stand history, located in a region with high N deposition (Belgium). Input-output N budgets were established by quantifying atmospheric deposition and leaching below the rooting zone, and confirmed the above finding of higher N deposition and disproportionately higher N loss for the pine stand compared to the oak stand. First, the fate of inorganic N within the ecosystems was studied by spraying three pulses of dissolved 15N, either as ammonium or as nitrate, onto the forest floor in 12 plots of 25 m2. The organic and mineral soil layers, tree roots, soil water percolate, ferns, and tree foliage were sampled

  13. Parasitism at the landscape scale: Cowbirds prefer forests

    USGS Publications Warehouse

    Hahn, D.C.; Hatfield, J.S.

    1995-01-01

    Landscape-scale examination of parasitism patterns of Brown-headed Cowbirds (Molothrus ater) revealed heterogeneous parasitism rates across the mosaic of a forest and associated oldfield communities. In a two-year study in Dutchess County, New York, we found a significantly higher parasitism rate in the forest-interior community (n = 301 nests; 17 species) than on the species in the adjacent and nearby old-field and edge (n = 328 nests; 15 species; 32.3% versus 6.5%; p lt 0.0001). Cowbirds invaded a mature 1300-ha forest stand even when their traditional host species were available in adjacent old-field and edge habitats. The forest and old field study areas were located in a 38,000-ha township with 55% forest cover and contained numerous agriculture, dairy, and horse farms that provided favorable habitat for cowbirds, within-forest examination of parasitism patterns revealed four aspects of cowbird parasitism that contrasted with patterns described in other regions; (1) parasitism was concentrated significantly more often on ground and low-nesting (nests ltoreq 1 m) forest species than on medium- and high nesting species (nests gt 1 m; 35. 01 % versus 2993%; p = 0.0393); (2) parasitism was not significantly greater on Neotropical migrant species than on short-distance migrants and residents; (3) the parasitism rate was not higher in nests close to edges; and (4) the parasitism level was low on certain forest species (such as Wood Thrush) that have experienced high parasitism levels in the Midwest. From a management perspective these data suggest that cowbirds exhibit regional differences in host and habitat use; the target host community of a particular cowbird population is unpredictable at the landscape scale; and a landscape scale should be used in designing cowbird studies to accurately assess local population dynamics.

  14. Old and Not-So-Old: Examining Changes in Forest Ecosystem Carbon Exchange With Stand Age in the Upper Midwest U.S.

    NASA Astrophysics Data System (ADS)

    Desai, A. R.; Cook, B.; Davis, K. J.; Bolstad, P.; Carey, E.; Martin, J.; Kreller, L.; Wang, W.

    2003-12-01

    Forest stand age is an important determinant of ecosystem carbon uptake. Though there are biometric measurements and ecological models for forests of all ages, there are few stand-scale eddy-flux measurements of net carbon exchange in older forests, though the number is increasing. In order to scale carbon fluxes from sites to regions, where stands of multiple ages may exist, it is necessary to measure to the effect of stand age on carbon exchange. Measuring the effect of stand age on carbon exchange is also necessary when trying to predict future or past carbon exchange (scaling across time). Many researchers have noted that site disturbance history is the fundamental factor in determining carbon uptake by forests over time scales of decades to centuries. The 8,500 ha Sylvania Wilderness in the upper peninsula of Michigan is one of several large tracts of old-growth forest in the Midwest. Trees range from 0-350 years old. Primary species are sugar maple, eastern hemlock and yellow birch. Catastrophic disturbance is rare. A research plot near the wilderness was established in late 2001 to measure the net ecosystem exchange (NEE) of carbon and water using eddy-flux, component flux and biometric methods. This site is part of the Chequamegon Ecosystem Atmosphere Study (ChEAS, http://cheas.psu.edu), a loose affiliation of researchers conducting carbon and water research in northern Wisconsin and upper Michigan. Another similar research plot within ChEAS and not far from Sylvania is the Willow Creek mature uplands site. This forest is about 70 years old and the primary species are sugar maple, basswood and green ash. The site had presettlement old-growth vegetation similar to what is currently seen in the Sylvania Wilderness. Thus, the carbon exchange seen at Sylvania may be representative of carbon uptake at Willow Creek had it not been logged in the early 20th century, and may also represent the future (or past) carbon uptake for similar forests in northern Wisconsin

  15. Mapping spatial distribution of forest age in China

    NASA Astrophysics Data System (ADS)

    Zhang, Yuan; Yao, Yitong; Wang, Xuhui; Liu, Yongwen; Piao, Shilong

    2017-03-01

    Forest stand age is a meaningful metric, which reflects the past disturbance legacy, provides guidelines for forest management practices, and is an important factor in qualifying forest carbon cycles and carbon sequestration potential. Reliable large-scale forest stand age information with high spatial resolutions, however, is difficult to obtain. In this study, we developed a top-down method to downscale the provincial statistics of national forest inventory data into 1 km stand age map using climate data and light detection and ranging-derived forest height. We find that the distribution of forest stand age in China is highly heterogeneous across the country, with a mean value of 42.6 years old. The relatively young stand age for Chinese forests is mostly due to the large proportion of newly planted forests (0-40 years old), which are more prevailing in south China. Older forests (stand age > 60 years old) are more frequently found in east Qinghai-Tibetan Plateau and the central mountain areas of west and northeast China, where human activities are less intensive. Among the 15 forest types, forests dominated by species of Taxodiaceae, with the exception of Cunninghamia lanceolata stands, have the oldest mean stand age (136 years), whereas Pinus massoniana forests are the youngest (18 years). We further identified uncertainties associated with our forest age map, which are high in west and northeast China. Our work documents the distribution of forest stand age in China at a high resolution which is useful for carbon cycle modeling and the sustainable use of China's forest resources.

  16. Denitrification in sediments from the hyporheic zone adjacent to a small forested stream

    USGS Publications Warehouse

    Duff, J.H.; Triska, F.J.

    1990-01-01

    Denitrifying potentials increased with increasing distance from the stream channel. Dissolved oxygen was 100% of the concentration expected in equilibrium with the atmosphere in water obtained from monitoring wells immediately adjacent to the stream but was as low as 7% of the expected value in water 11.4 m inland. Both nitrate and dissolved organic carbon decreased over summer in wells at the base of the alder-forested slope. A 48-h injection of nitrate-amended stream water into hyporheic water 8.4 m inland stimulated nitrous oxide production in the presence of acetylene. Nitrous oxide was generated as nitrate and acetylene were co-transported to a well 13 m down-gradient. Acetylene-block experiments coupled with the chemistry data suggest that denitrification can modify the chemistry of water during passage through the hyporheic zone. -from Authors

  17. Allometric Scaling and Resource Limitations Model of Total Aboveground Biomass in Forest Stands: Site-scale Test of Model

    NASA Astrophysics Data System (ADS)

    CHOI, S.; Shi, Y.; Ni, X.; Simard, M.; Myneni, R. B.

    2013-12-01

    Sparseness in in-situ observations has precluded the spatially explicit and accurate mapping of forest biomass. The need for large-scale maps has raised various approaches implementing conjugations between forest biomass and geospatial predictors such as climate, forest type, soil property, and topography. Despite the improved modeling techniques (e.g., machine learning and spatial statistics), a common limitation is that biophysical mechanisms governing tree growth are neglected in these black-box type models. The absence of a priori knowledge may lead to false interpretation of modeled results or unexplainable shifts in outputs due to the inconsistent training samples or study sites. Here, we present a gray-box approach combining known biophysical processes and geospatial predictors through parametric optimizations (inversion of reference measures). Total aboveground biomass in forest stands is estimated by incorporating the Forest Inventory and Analysis (FIA) and Parameter-elevation Regressions on Independent Slopes Model (PRISM). Two main premises of this research are: (a) The Allometric Scaling and Resource Limitations (ASRL) theory can provide a relationship between tree geometry and local resource availability constrained by environmental conditions; and (b) The zeroth order theory (size-frequency distribution) can expand individual tree allometry into total aboveground biomass at the forest stand level. In addition to the FIA estimates, two reference maps from the National Biomass and Carbon Dataset (NBCD) and U.S. Forest Service (USFS) were produced to evaluate the model. This research focuses on a site-scale test of the biomass model to explore the robustness of predictors, and to potentially improve models using additional geospatial predictors such as climatic variables, vegetation indices, soil properties, and lidar-/radar-derived altimetry products (or existing forest canopy height maps). As results, the optimized ASRL estimates satisfactorily

  18. Nitrogen, phosphorus, and cation use efficiency in stands of regenerating tropical dry forest.

    PubMed

    Waring, Bonnie G; Becknell, Justin M; Powers, Jennifer S

    2015-07-01

    Plants on infertile soils exhibit physiological and morphological traits that support conservative internal nutrient cycling. However, potential trade-offs among use efficiencies for N, P, and cations are not well explored in species-rich habitats where multiple elements may limit plant production. We examined uptake efficiency and use efficiency of N, P, K, Ca, Mg, Al, and Na in plots of regenerating tropical dry forests spanning a gradient of soil fertility. Our aim was to determine whether plant responses to multiple elements are correlated, or whether there are trade-offs among exploitation strategies across stands varying in community composition, soil quality, and successional stage. For all elements, both uptake efficiency and use efficiency decreased as availability of the corresponding element increased. Plant responses to N, Na, and Al were uncoupled from uptake and use efficiencies for P and essential base cations, which were tightly correlated. N and P use efficiencies were associated with shifts in plant species composition along the soil fertility gradient, and there was also a trend towards increasing N use efficiency with stand age. N uptake efficiency was positively correlated with the abundance of tree species that associate with ectomycorrhizal fungi. Taken together, our results suggest that successional processes and local species composition interact to regulate plant responses to availability of multiple resources. Successional tropical dry forests appear to employ different strategies to maximize response to N vs. P and K.

  19. Effects of dwarf mistletoe on stand structure of lodgepole pine forests 21-28 years post-mountain pine beetle epidemic in central Oregon

    Treesearch

    Michelle C. Agne; David C. Shaw; Travis J. Woolley; Mónica E. Queijeiro-Bolaños; Mai-He. Li

    2014-01-01

    Lodgepole pine (Pinus contorta) forests are widely distributed throughout North America and are subject to mountain pine beetle (Dendroctonus ponderosae) epidemics, which have caused mortality over millions of hectares of mature trees in recent decades. Mountain pine beetle is known to influence stand structure, and has the ability to impact many forest processes....

  20. Structural characteristics of forest stands within home ranges of Mexican spotted owls in Arizona and New Mexico

    Treesearch

    Joseph L. Ganey; William M. Block; Steven H. Ackers

    2003-01-01

    As part of a set of studies evaluating home-range size and habitat use of radio-marked Mexican spotted owls (Strix occidentalis lucida), we sampled structural characteristics of forest stands within owl home ranges on two study areas in Arizona and New Mexico. Study areas were dominated by ponderosa pine (Pinus ponderosa)-Gambel...

  1. Influence of stand density on soil CO2 efflux for a Pinus densiflora forest in Korea.

    PubMed

    Noh, Nam Jin; Son, Yowhan; Lee, Sue Kyoung; Yoon, Tae Kyung; Seo, Kyung Won; Kim, Choonsig; Lee, Woo-Kyun; Bae, Sang Won; Hwang, Jaehong

    2010-07-01

    We investigated the influence of stand density [938 tree ha(-1) for high stand density (HD), 600 tree ha(-1) for medium stand density (MD), and 375 tree ha(-1) for low stand density (LD)] on soil CO(2) efflux (R (S)) in a 70-year-old natural Pinus densiflora S. et Z. forest in central Korea. Concurrent with R (S) measurements, we measured litterfall, total belowground carbon allocation (TBCA), leaf area index (LAI), soil temperature (ST), soil water content (SWC), and soil nitrogen (N) concentration over a 2-year period. The R (S) (t C ha(-1) year(-1)) and leaf litterfall (t C ha(-1) year(-1)) values varied with stand density: 6.21 and 2.03 for HD, 7.45 and 2.37 for MD, and 6.96 and 2.23 for LD, respectively. In addition, R (S) was correlated with ST (R (2) = 0.77-0.80, P < 0.001) and SWC (R (2) = 0.31-0.35, P < 0.001). It appeared that stand density influenced R (S) via changes in leaf litterfall, LAI and SWC. Leaf litterfall (R (2) = 0.71), TBCA (R (2) = 0.64-0.87), and total soil N contents in 2007 (R (2) = 0.94) explained a significant amount of the variance in R (S) (P < 0.01). The current study showed that stand density is one of the key factors influencing R (S) due to the changing biophysical and environmental factors in P. densiflora.

  2. Rapid rebound of soil respiration following partial stand disturbance by tree girdling in a temperate deciduous forest.

    PubMed

    Levy-Varon, Jennifer H; Schuster, William S F; Griffin, Kevin L

    2014-04-01

    Forests serve an essential role in climate change mitigation by removing CO2 from the atmosphere. Within a forest, disturbance events can greatly impact C cycling and subsequently influence the exchange of CO2 between forests and the atmosphere. This connection makes understanding the forest C cycle response to disturbance imperative for climate change research. The goal of this study was to examine the temporal response of soil respiration after differing levels of stand disturbance for 3 years at the Black Rock Forest (southeastern NY, USA; oaks comprise 67% of the stand). Tree girdling was used to mimic pathogen attack and create the following treatments: control, girdling all non-oaks (NOG), girdling half of the oak trees (O50), and girdling all the oaks (OG). Soil respiratory rates on OG plots declined for 2 years following girdling before attaining a full rebound of belowground activity in the third year. Soil respiration on NOG and O50 were statistically similar to the control for the duration of the study although a trend for a stronger decline in respiration on O50 relative to NOG occurred in the first 2 years. Respiratory responses among the various treatments were not proportional to the degree of disturbance and varied over time. The short-lived respiratory response on O50 and OG suggests that belowground activity is resilient to disturbance; however, sources of the recovered respiratory flux on these plots are likely different than they were pre-treatment. The differential taxon response between oaks and non-oaks suggests that after a defoliation or girdling event, the temporal response of the soil respiratory flux may be related to the C allocation pattern of the affected plant group.

  3. Productivity of a mature Douglas-fir stand.

    Treesearch

    Carl M. Berntsen

    1960-01-01

    Records from a mature Douglas-fir stand on the Mount Hood National Forest in northwestern Oregon indicate that very high rates of gross growth are maintained up to ages as high as 250 years. Where such stands are held in reserve for future clear cutting, forest managers have an opportunity to recapture a large share of this gross production by salvaging mortality at...

  4. Deposition pattern and throughfall fluxes in secondary cool temperate forest, South Korea

    NASA Astrophysics Data System (ADS)

    Kumar Gautam, Mukesh; Lee, Kwang-Sik; Song, Byeong-Yeol

    2017-07-01

    Chemistry and deposition fluxes in the rainfall and throughfall of red pine (Pinus densiflora), black locust (Robinia pseudoacacia), and chestnut (Castanea crenata) monocultures, and mixed red pine-black locust-chestnut stands were examined in a nutrient-limited cool temperate forest of central South Korea. Throughfall was enriched in both basic and acidic constituents relative to rainfall, suggesting that both dry deposition and canopy leaching are important sources of throughfall constituents. Net throughfall fluxes (NTFs) of cations and anions significantly differed among four different stands as well as seasonally. Red pine exhibited highest fluxes (TF and NTF) for Ca2+, black locust for K+, mixed stands for Mg2+, and chestnut for Na+. In contrast, NTF of SO42-, NO3-, and NH4+was highest in the red pine, intermediate in the chestnut and mixed stands, and lowest in the black locust. In general, canopy uptake of H+ and NH4+ for all stands was higher in summer than in winter. Dry deposition appears to play a major role in atmospheric deposition to this cool temperate forest, especially in summer. Dry deposition for both cations and anions displayed high spatial variability, even though stands were adjacent to one another and experienced identical atmospheric deposition loads. Canopy leaching of K+ (95-78% of NTF), Mg2+ (92-23% of NTF), and Ca2+ (91-12% of NTF) was highest for the black locust, lowest for chestnut, and intermediate for the red pine and mixed stands. The present study documented significant changes in throughfall chemistry and NTF among different forest stands, which presumably be related with the differences in the canopy characteristics and differences in their scavenging capacity for dry deposition and canopy exchange. Difference in the canopy retention of H+ and base cation leaching suggests that canopy exchange was mainly driven by weak acid excretion and lesser by H+ exchange reaction. Our results indicate that despite a high base cation

  5. Detection of forest stand-level spatial structure in ectomycorrhizal fungal communities.

    PubMed

    Lilleskov, Erik A; Bruns, Thomas D; Horton, Thomas R; Taylor, D; Grogan, Paul

    2004-08-01

    Ectomycorrhizal fungal (EMF) communities are highly diverse at the stand level. To begin to understand what might lead to such diversity, and to improve sampling designs, we investigated the spatial structure of these communities. We used EMF community data from a number of studies carried out in seven mature and one recently fire-initiated forest stand. We applied various measures of spatial pattern to characterize distributions at EMF community and species levels: Mantel tests, Mantel correlograms, variance/mean and standardized variograms. Mantel tests indicated that in four of eight sites community similarity decreased with distance, whereas Mantel correlograms also found spatial autocorrelation in those four plus two additional sites. In all but one of these sites elevated similarity was evident only at relatively small spatial scales (< 2.6 m), whereas one exhibited a larger scale pattern ( approximately 25 m). Evenness of biomass distribution among cores varied widely among taxa. Standardized variograms indicated that most of the dominant taxa showed patchiness at a scale of less than 3 m, with a range from 0 to < or =17 m. These results have implications for both sampling scale and intensity to achieve maximum efficiency of community sampling. In the systems we examined, cores should be at least 3 m apart to achieve the greatest sampling efficiency for stand-level community analysis. In some cases even this spacing may result in reduced sampling efficiency arising from patterns of spatial autocorrelation. Interpretation of the causes and significance of these patterns requires information on the genetic identity of individuals in the communities.

  6. Spring bird migration in Mississippi Alluvial Valley forests

    USGS Publications Warehouse

    Wilson, R. Randy; Twedt, Daniel J.

    2003-01-01

    We surveyed forest songbirds during migration in bottomland hardwood forest stands and managed cottonwood (Populus deltoides) plantations in northeast Louisiana and west-central Mississippi between 24 March and 24 May 1996 and 1997. We detected more bird species in bottomland hardwood stands than in cottonwood stands. Within hardwood stands, we detected more individuals in stands subjected to uneven-aged timber harvest than in unmanaged stands. Early in migration, avian species composition was similar in both forest types, being comprised mainly of short-distance migrants. Bird species composition in these forest types became increasingly disparate as long-distance neotropical-nearctic migrants arrived. Ten bird species were characteristic of bottomland hardwood forests, whereas eight different species were characteristic of managed cottonwood plantations. Because these two forest types supported different bird communities, both forest types provide important inland stopover habitat during migration. Silvicultural management of bottomland hardwood forests that increases their understory vegetation will provide forested habitat for a more species rich and abundant population of songbirds during migration.

  7. Post-Disturbance Plant Community Dynamics following a Rare Natural-Origin Fire in a Tsuga canadensis Forest

    PubMed Central

    Murray, Bryan D.; Holmes, Stacie A.; Webster, Christopher R.; Witt, Jill C.

    2012-01-01

    Opportunities to directly study infrequent forest disturbance events often lead to valuable information about vegetation dynamics. In mesic temperate forests of North America, stand-replacing crown fire occurs infrequently, with a return interval of 2000–3000 years. Rare chance events, however, may have profound impacts on the developmental trajectories of forest ecosystems. For example, it has been postulated that stand-replacing fire may have been an important factor in the establishment of eastern hemlock (Tsuga canadensis) stands in the northern Great Lakes region. Nevertheless, experimental evidence linking hemlock regeneration to non-anthropogenic fire is limited. To clarify this potential relationship, we monitored vegetation dynamics following a rare lightning-origin crown fire in a Wisconsin hemlock-hardwood forest. We also studied vegetation in bulldozer-created fire breaks and adjacent undisturbed forest. Our results indicate that hemlock establishment was rare in the burned area but moderately common in the scarified bulldozer lines compared to the reference area. Early-successional, non-arboreal species including Rubus spp., Vaccinium angustifolium, sedges (Carex spp.), grasses, Epilobium ciliatum, and Pteridium aquilinium were the most abundant post-fire species. Collectively, our results suggest that competing vegetation and moisture stress resulting from drought may reduce the efficacy of scarification treatments as well as the usefulness of fire for preparing a suitable seedbed for hemlock. The increasing prevalence of growing-season drought suggests that silvicultural strategies based on historic disturbance regimes may need to be reevaluated for mesic species. PMID:22928044

  8. Large sample area and size are needed for forest soil seed bank studies to ensure low discrepancy with standing vegetation.

    PubMed

    Shen, You-xin; Liu, Wei-li; Li, Yu-hui; Guan, Hui-lin

    2014-01-01

    A large number of small-sized samples invariably shows that woody species are absent from forest soil seed banks, leading to a large discrepancy with the seedling bank on the forest floor. We ask: 1) Does this conventional sampling strategy limit the detection of seeds of woody species? 2) Are large sample areas and sample sizes needed for higher recovery of seeds of woody species? We collected 100 samples that were 10 cm (length) × 10 cm (width) × 10 cm (depth), referred to as larger number of small-sized samples (LNSS) in a 1 ha forest plot, and placed them to germinate in a greenhouse, and collected 30 samples that were 1 m × 1 m × 10 cm, referred to as small number of large-sized samples (SNLS) and placed them (10 each) in a nearby secondary forest, shrub land and grass land. Only 15.7% of woody plant species of the forest stand were detected by the 100 LNSS, contrasting with 22.9%, 37.3% and 20.5% woody plant species being detected by SNLS in the secondary forest, shrub land and grassland, respectively. The increased number of species vs. sampled areas confirmed power-law relationships for forest stand, the LNSS and SNLS at all three recipient sites. Our results, although based on one forest, indicate that conventional LNSS did not yield a high percentage of detection for woody species, but SNLS strategy yielded a higher percentage of detection for woody species in the seed bank if samples were exposed to a better field germination environment. A 4 m2 minimum sample area derived from power equations is larger than the sampled area in most studies in the literature. Increased sample size also is needed to obtain an increased sample area if the number of samples is to remain relatively low.

  9. A stand-alone tree demography and landscape structure module for Earth system models: integration with inventory data from temperate and boreal forests

    NASA Astrophysics Data System (ADS)

    Haverd, V.; Smith, B.; Nieradzik, L. P.; Briggs, P. R.

    2014-08-01

    Poorly constrained rates of biomass turnover are a key limitation of Earth system models (ESMs). In light of this, we recently proposed a new approach encoded in a model called Populations-Order-Physiology (POP), for the simulation of woody ecosystem stand dynamics, demography and disturbance-mediated heterogeneity. POP is suitable for continental to global applications and designed for coupling to the terrestrial ecosystem component of any ESM. POP bridges the gap between first-generation dynamic vegetation models (DVMs) with simple large-area parameterisations of woody biomass (typically used in current ESMs) and complex second-generation DVMs that explicitly simulate demographic processes and landscape heterogeneity of forests. The key simplification in the POP approach, compared with second-generation DVMs, is to compute physiological processes such as assimilation at grid-scale (with CABLE (Community Atmosphere Biosphere Land Exchange) or a similar land surface model), but to partition the grid-scale biomass increment among age classes defined at sub-grid-scale, each subject to its own dynamics. POP was successfully demonstrated along a savanna transect in northern Australia, replicating the effects of strong rainfall and fire disturbance gradients on observed stand productivity and structure. Here, we extend the application of POP to wide-ranging temporal and boreal forests, employing paired observations of stem biomass and density from forest inventory data to calibrate model parameters governing stand demography and biomass evolution. The calibrated POP model is then coupled to the CABLE land surface model, and the combined model (CABLE-POP) is evaluated against leaf-stem allometry observations from forest stands ranging in age from 3 to 200 year. Results indicate that simulated biomass pools conform well with observed allometry. We conclude that POP represents an ecologically plausible and efficient alternative to large-area parameterisations of woody

  10. Seasonal Habitat Distribution Of Swamp Rabbits, White-Tailed Deer, and Small Mammals in Old Growth and Managed Bottomland Hardwood Forests

    Treesearch

    Winston P. Smith; Patrick A. Zollner

    2001-01-01

    We studied swamp rabbits, white-tailed deer, and small mammals in an old-growth and adjacent second-growth and young-growth bottomland hardwood forest stands in southern Arkansas, August 1991 – February 1993. Based on average home range size and degree of overlap, minimum and maximum density estimates of swamp rabbits were 31 per km2 (no overlap)...

  11. Soil respiration rates and δ13C(CO2) in natural beech forest (Fagus sylvatica L.) in relation to stand structure.

    PubMed

    Cater, Matjaz; Ogrinc, Nives

    2011-06-01

    Soil respiration rates were studied as a function of soil type, texture and light intensity at five selected natural beech forest stands with contrasting geology: stands on silicate bedrock at Kladje and Bricka in Pohorje, a stand on quartz sandstone at Vrhovo and two stands on a carbonate bedrock in the Karstic-Dinaric area in Kocevski Rog, Snezna jama and Rajhenav, Slovenia, during the growing season in 2005-2006. Soil respiration exhibited pronounced seasonal and spatial variations in the studied forest ecosystem plots. The CO(2) flux rates ranged from minimum averages of 2.3 μmol CO(2) m(-2) s(-1) (winter) to maximum averages of about 7 μmol CO(2) m(-2) s(-1) (summer) at all the investigated locations. An empirical model describing the relationship between soil respiration and soil temperature predicted seasonal variations in soil respiration reasonably well during 2006. Nevertheless, there were also some indications that soil moisture in relation to soil texture could influence the soil CO(2) efflux rates in both sampling seasons. It was shown that spatial variability of mean soil respiration at the investigated sites was high and strongly related to root biomass. Based on the [image omitted]  data, it was shown that new photoassimilates could account for a major part of the total soil respiration under canopy conditions in forest ecosystems where no carbonate rocks are present, indicating that microbial respiration could not always dominate bulk soil CO(2) fluxes. At Snezna jama and Rajhenav, the abiotic CO(2) derived from carbonate dissolution had a pronounced influence on CO(2) efflux accounting, on average, to ∼17%. Further spatial heterogeneity of soil respiration was clearly affected by management practice. Higher respiration rates as well as higher variability in respiration rates were observed in the virgin forest (Rajhenav) than in the management forest (Snezna jama) and could be related to a higher amount of detritus and consequently to less

  12. Rehabilitation of Understocked Loblolly-Shortleaf Pine Stands - I. Recently Cutover Natural Stands

    Treesearch

    James B. Baker; Michael G. Shelton

    1998-01-01

    A 1988 USDA Forest Service report indicated that 22% (40 million ac) of the commercial timberland in the South was understocked (less than 60% stocking) with desirable tree species for timber production (USDA Forest Service 1988). The understocked stands are usually the result of past har-vesting practices, natural catastrophes, or regeneration fail-ures. Understocked...

  13. Foliar free polyamine and inorganic ion content in relation to soil and soil solution chemistry in two fertilized forest stands at the Harvard Forest, Massachusetts

    Treesearch

    Rakesh Minocha; Stephanie Long; Alison H. Magill; John Aber; William H. McDowell

    2000-01-01

    Polyamines (putrescine, spermidine, and spermine) are low molecular weight, open-chained, organic polycations which are found in all organisms and have been linked with stress responses in plants. The objectives of our study were to investigate the effects of chronic N additions to pine and hardwood stands at Harvard Forest, Petersham, MA on foliar polyamine and...

  14. Variability in early height growth rate of forest trees: implications for retrospective studies of stand dynamics

    Treesearch

    Brain J. Palik; Kurt S. Pregitzer

    1995-01-01

    Retrospective studies of forest stand dynamics may rely on estimates of tree ages. In some of these studies, trees are aged near the stem base, while in other studies trees may be aged at breast height. An age correction may be added to breast-height ages in an attempt to account for average time to reach breast height and thus provide better estimates of total ages....

  15. Volume and weight characteristics of a typical Douglas-fir/ western larch stand, Coram Experimental Forest, Montana

    Treesearch

    Robert E. Benson; Joyce A. Schlieter

    1980-01-01

    An over-mature Douglas-fir/western larch stand on the Coram Experimental Forest in Montana averaged about 7,300 ft3/acre (511 rn3/ha) of wood over 3 inches (7.62 cm) in diameter, and an additional 57 tons/acre (128/ha) of fine material, before harvest. After logging, using three different cutting methods and four different levels of utilization, wood residues ranged...

  16. Species Composition, Tree Quality and Wood Properties of Southern Pine Stands Under Ecosystemm Management on National Forests in the Peidmont and Coastal Plain

    Treesearch

    Alexander Clark; James W. McMinn

    1999-01-01

    National Forests in the United States are under sustainable ecosystem management to conserve biodiversity, achieve sustainable conditions and improve the balance among forest values. This paper reports on a study established to identify the implications of ecosystem management strategies on natural stands in the Piedmont and Coastal Plain. The impact of partial...

  17. Economic considerations in Douglas-fir stand establishment.

    Treesearch

    T.A. McClay

    1955-01-01

    One of the most important problem facing a forest manager is how to successfully bridge the gap between the cutting of the old stand and establishment of the new one. Perhaps its importance is due to the fact that it requires prompt action based upon definite planning. At most other points in a forest stand's history, failure to take action is not quite so obvious...

  18. A database for the monitoring of thermal anomalies over the Amazon forest and adjacent intertropical oceans

    PubMed Central

    Jiménez-Muñoz, Juan C.; Mattar, Cristian; Sobrino, José A.; Malhi, Yadvinder

    2015-01-01

    Advances in information technologies and accessibility to climate and satellite data in recent years have favored the development of web-based tools with user-friendly interfaces in order to facilitate the dissemination of geo/biophysical products. These products are useful for the analysis of the impact of global warming over different biomes. In particular, the study of the Amazon forest responses to drought have recently received attention by the scientific community due to the occurrence of two extreme droughts and sustained warming over the last decade. Thermal Amazoni@ is a web-based platform for the visualization and download of surface thermal anomalies products over the Amazon forest and adjacent intertropical oceans using Google Earth as a baseline graphical interface (http://ipl.uv.es/thamazon/web). This platform is currently operational at the servers of the University of Valencia (Spain), and it includes both satellite (MODIS) and climatic (ERA-Interim) datasets. Thermal Amazoni@ is composed of the viewer system and the web and ftp sites with ancillary information and access to product download. PMID:26029379

  19. A database for the monitoring of thermal anomalies over the Amazon forest and adjacent intertropical oceans.

    PubMed

    Jiménez-Muñoz, Juan C; Mattar, Cristian; Sobrino, José A; Malhi, Yadvinder

    2015-01-01

    Advances in information technologies and accessibility to climate and satellite data in recent years have favored the development of web-based tools with user-friendly interfaces in order to facilitate the dissemination of geo/biophysical products. These products are useful for the analysis of the impact of global warming over different biomes. In particular, the study of the Amazon forest responses to drought have recently received attention by the scientific community due to the occurrence of two extreme droughts and sustained warming over the last decade. Thermal Amazoni@ is a web-based platform for the visualization and download of surface thermal anomalies products over the Amazon forest and adjacent intertropical oceans using Google Earth as a baseline graphical interface (http://ipl.uv.es/thamazon/web). This platform is currently operational at the servers of the University of Valencia (Spain), and it includes both satellite (MODIS) and climatic (ERA-Interim) datasets. Thermal Amazoni@ is composed of the viewer system and the web and ftp sites with ancillary information and access to product download.

  20. Estimation of crown biomass of Pinus pinaster stands and shrubland above-ground biomass using forest inventory data, remotely sensed imagery and spatial prediction models

    Treesearch

    H. Viana; J. Aranha; D. Lopes; Warren B. Cohen

    2012-01-01

    Spatially crown biomass of Pinus pinaster stands and shrubland above-ground biomass (AGB) estimation was carried-out in a region located in Centre-North Portugal, by means of different approaches including forest inventory data, remotely sensed imagery and spatial prediction models. Two cover types (pine stands and shrubland) were inventoried and...

  1. User's Guide to the Stand Prognosis Model

    Treesearch

    William R. Wykoff; Nicholas L. Crookston; Albert R. Stage

    1982-01-01

    The Stand Prognosis Model is a computer program that projects the development of forest stands in the Northern Rocky Mountains. Thinning options allow for simulation of a variety of management strategies. Input consists of a stand inventory, including sample tree records, and a set of option selection instructions. Output includes data normally found in stand, stock,...

  2. Test of four stand growth simulators for the northeastern United States

    Treesearch

    Thomas M. Schuler; David A. Marquis; Richard L. Ernst; Brian T. Simpson; Brian T. Simpson

    1993-01-01

    Evaluates SILVAH, FIBER, NE-TWIGS, and OAKSIM, simulators commonly used in the northeastern United States, by comparing predicted stand development with actual stand development records for periods ranging from 15 to 50 years. Results varied with stand parameter, forest type, projection length, and geographic area. Except in the spruce-fir forest type where FIBER...

  3. Mycorrhizal associations in Ailanthus altissima (Simaroubaceae) from forested and non-forested sites

    Treesearch

    Cynthia D. Huebner; Carolyn McQuattie; Joanne Rebbeck

    2007-01-01

    Ailanthus altissima tree seedlings were excavated from each of two habitats: (1) a forest adjacent to a trail and stream and (2) a non-forested steep, barren slope adjacent to a major highway. Each seedling root system was examined for colonization by mycorrhizal structures using light microscopy and transmission electron microscopy. The roots were...

  4. Effect of prior disturbances on the extent and severity of wildfire in Colorado subalpine forests.

    PubMed

    Kulakowski, Dominik; Veblen, Thomas T

    2007-03-01

    Disturbances are important in creating spatial heterogeneity of vegetation patterns that in turn may affect the spread and severity of subsequent disturbances. Between 1997 and 2002 extensive areas of subalpine forests in northwestern Colorado were affected by a blowdown of trees, bark beetle outbreaks, and salvage logging. Some of these stands were also affected by severe fires in the late 19th century. During a severe drought in 2002, fires affected extensive areas of these subalpine forests. We evaluated and modeled the extent and severity of the 2002 fires in relation to these disturbances that occurred over the five years prior to the fires and in relation to late 19th century stand-replacing fires. Occurrence of disturbances prior to 2002 was reconstructed using a combination of tree-ring methods, aerial photograph interpretation, field surveys, and geographic information systems (GIS). The extent and severity of the 2002 fires were based on the normalized difference burn ratio (NDBR) derived from satellite imagery. GIS and classification trees were used to analyze the effects of prefire conditions on the 2002 fires. Previous disturbance history had a significant influence on the severity of the 2002 fires. Stands that were severely blown down (> 66% trees down) in 1997 burned more severely than other stands, and young (approximately 120 year old) postfire stands burned less severely than older stands. In contrast, prefire disturbances were poor predictors of fire extent, except that young (approximately 120 years old) postfire stands were less extensively burned than older stands. Salvage logging and bark beetle outbreaks that followed the 1997 blowdown (within the blowdown as well as in adjacent forest that was not blown down) did not appear to affect fire extent or severity. Conclusions regarding the influence of the beetle outbreaks on fire extent and severity are limited, however, by spatial and temporal limitations associated with aerial detection

  5. Accounting for density reduction and structural loss in standing dead trees: Implications for forest biomass and carbon stock estimates in the United States

    Treesearch

    Grant M. Domke; Christopher W. Woodall; James E. Smith

    2011-01-01

    Standing dead trees are one component of forest ecosystem dead wood carbon (C) pools, whose national stock is estimated by the U.S. as required by the United Nations Framework Convention on Climate Change. Historically, standing dead tree C has been estimated as a function of live tree growing stock volume in the U.S.'s National Greenhouse Gas Inventory. Initiated...

  6. Species composition, diameter distribution, and crown class at initiation of a thinning study of pole-size hardwood stands in the Hoosier National Forest

    Treesearch

    Ryan L. Woods; Douglass F. Jacobs

    2008-01-01

    During the spring of 2007, a low thinning was implemented in stands on the Hoosier National Forest that had been clearcut harvested between 1975 and 1979; treatments consisted of 60- and 75-percent residual stocking, as well as control plots with no thinning. The 60-percent treatment increased the relative oak density per acre in all stands with the exception of one...

  7. Forest resources of Pennsylvania

    Treesearch

    Richard H. Widmann; Richard H. Widmann

    1995-01-01

    Phis report presents an analysis of the results of the 1989 forest inventory of Pennsylvania as well as trends that habe occurred since the previous survey. Major topics include changes in forest land by ownership, forest type, and timberland component7 stand structure is charaterized by stand size, understory woody vegetation, dead trees, and changes in relative...

  8. Above-ground sulfur cycling in adjacent coniferous and deciduous forest and watershed sulfur retention in the Georgia Piedmont, U.S.A.

    USGS Publications Warehouse

    Cappellato, R.; Peters, N.E.; Meyers, T.P.

    1998-01-01

    Atmospheric deposition and above-ground cycling of sulfur (S) were evaluated in adjacent deciduous and coniferous forests at the Panola Mountain Research Watershed (PMRW), Georgia U.S.A. Total atmospheric S deposition (wet plus dry) was 12.9 and 12.7 kg ha-1 yr-1 for the deciduous and coniferous forests, respectively, from October 1987 through November 1989. Dry deposition contributes more than 40% to the total atmospheric S deposition, and SO2 is the major source (~55%) of total dry S deposition. Dry deposition to these canopies is similar to regional estimates suggesting that 60-km proximity to emission sources does not noticeably impact dry deposition at PMRW. Below-canopy S fluxes (throughfall plus stemflow) in each forest are 37% higher annually in the deciduous forest than in the coniferous forest. An excess in below-canopy S flux in the deciduous forest is attributed to leaching and higher dry deposition than in the coniferous forest. Total S deposition to the forest floor by throughfall, stemflow and litterfall was 2.4 and 2.8 times higher in the deciduous and coniferous forests, respectively, than annual S growth requirement for foliage and wood. Although A deposition exceeds growth requirement, more than 95% of the total atmospheric S deposition was retained by the watershed in 1988 and 1989. The S retention at PMRW is primarily due to SO2+4 adsorption by iron oxides and hydroxides in watershed soils. The S content in while oak and loblolly pine boles have increased more than 200% in the last 20 yr, possibly reflecting increases in emissions.

  9. Does nitrogen and sulfur deposition affect forest productivity?

    Treesearch

    Brittany A. Johnson; Kathryn B. Piatek; Mary Beth Adams; John R. Brooks

    2010-01-01

    We studied the effects of atmospheric nitrogen and sulfur deposition on forest productivity in a 10-year-old, aggrading forest stand at the Fernow Experimental Forest in Tucker County, WV. Forest productivity was expressed as total aboveground wood biomass, which included stem and branch weight of standing live trees. Ten years after stand regeneration and treatment...

  10. Managed forest reserves: preserving diversity

    USGS Publications Warehouse

    Tappeiner, John; Poage, Nathan; Erickson, Janet L.

    2003-01-01

    As part of the Northwest Forest Plan, large areas have been designated on many federal forests in western Oregon to provide critical habitat for plants and animals that are associated with old-growth habitat. Some of the structural characteristics often considered typical of old forests include large-diameter overstory trees, large standing and fallen dead trees, and one or more understory layers (Figure 1). However, not all of these areas are currently in old-growth conditions. Many of them contain young (<40 years), uniformly dense Douglas-fir stands that regenerated after timber harvest. The original management goal for these stands was to produce high yields of timber and associated wood products. With implementation of the Northwest Forest Plan in 1994, the management objective shifted to accelerating development of old-growth characteristics by enhancing structural and biological diversity of these areas.A major challenge today is how to promote these structural characteristics in younger stands. Researchers have been asking if lessons can be learned from the development of our current old growth and applied to management of younger stands. Dr. John Tappeiner and his university and agency research partners are helping to answer this question by examining the differences in development between old-growth and young stands in western Oregon. Understanding how the structure of these old forests developed may provide a model for management of young stands, especially when the management goal is to provide habitat for species associated with older forests.

  11. Nitrogen retention in contrasting temperate forests exposed to high nitrogen deposition

    NASA Astrophysics Data System (ADS)

    Staelens, J.; Adriaenssens, S.; Wuyts, K.; Verheyen, K.; Boeckx, P. F.

    2011-12-01

    A better understanding of factors affecting nitrogen (N) retention is needed to assess the impact of changing anthropogenic N emissions and climatic conditions on N cycling and N loss by terrestrial ecosystems. Retention of N has been demonstrated for a wide range of forests, including ecosystems exposed to chronically enhanced N deposition, but it is still unclear which factors determine this N retention capacity. Therefore, we examined the possible effects of forest type on N retention using stable N isotopes. The study was carried out in adjacent equal-aged deciduous (pedunculate oak (Quercus robur L.)) and coniferous (Scots pine (Pinus sylvestris L.)) stands with a similar stand history and growing on a well-drained sandy soil in a region with enhanced N deposition (Belgium). The N input-output budgets and gross soil N transformation rates differed significantly between the two stands. The forest floor was exposed to a high inorganic N input from atmospheric deposition, which was nearly twice as high in the pine stand (33 ± 2 kg N ha-1 yr-1; mean ± standard error) as in the oak stand (18 ± 1 kg N ha-1 yr-1). The N input was reflected in the soil solution under the rooting zone, but the mean nitrate concentration was eight times higher under pine (19 ± 5 mg N L-1) than under oak (2.3 ± 0.9 mg N L-1). Gross N dynamics in the mineral topsoil were determined by in situ 15N labelling of undisturbed soil cores combined with numerical data analysis. Gross N mineralization was two times faster in the oak soil while nitrate production was two times faster in the pine soil, indicating a dominant effect of vegetation cover on soil N cycling. The higher gross nitrification, particularly due to oxidation of organic N, in the pine soil compared to the oak soil, combined with negligible nitrate immobilization, was in line with the higher nitrate leaching under the pine forest. On a larger spatial and temporal scale, the fate of dissolved inorganic N within these forests

  12. Fuel-reduction management alters plant composition, carbon and nitrogen pools, and soil thaw in Alaskan boreal forest

    USGS Publications Warehouse

    Melvin, April M.; Celis, Gerardo; Johnstone, Jill F.; McGuire, A. David; Genet, Helene; Schuur, Edward A.G.; Rupp, T. Scott; Mack, Michelle C.

    2018-01-01

    Increasing wildfire activity in Alaska's boreal forests has led to greater fuel-reduction management. Management has been implemented to reduce wildfire spread, but the ecological impacts of these practices are poorly known. We quantified the effects of hand-thinning and shearblading on above- and belowground stand characteristics, plant species composition, carbon (C) and nitrogen (N) pools, and soil thaw across 19 black spruce (Picea mariana) dominated sites in interior Alaska treated 2-12 years prior to sampling. The density of deciduous tree seedlings was significantly higher in shearbladed areas compared to unmanaged forest (6.4 vs. 0.1 stems m−2), and unmanaged stands exhibited the highest mean density of conifer seedlings and layers (1.4 stems m−2). Understory plant community composition was most similar between unmanaged and thinned stands. Shearblading resulted in a near complete loss of aboveground tree biomass C pools while thinning approximately halved the C pool size (1.2 kg C m−2 compared to 3.1 kg C m−2 in unmanaged forest). Significantly smaller soil organic layer (SOL) C and N pools were observed in shearbladed stands (3.2 kg C m−2 and 116.8 g N m−2) relative to thinned (6.0 kg C m−2 and 192.2 g N m−2) and unmanaged (5.9 kg C m−2 and 178.7 g N m−2) stands. No difference in C and N pool sizes in the uppermost 10 cm of mineral soil was observed among stand types. Total C stocks for measured pools was 2.6 kg C m−2 smaller in thinned stands and 5.8 kg C m−2smaller in shearbladed stands when compared to unmanaged forest. Soil thaw depth averaged 13 cm deeper in thinned areas and 46 cm deeper in shearbladed areas relative to adjacent unmanaged stands, although variability was high across sites. Deeper soil thaw was linked to shallower SOL depth for unmanaged stands and both management types, however for any given SOL depth, thaw tended to be deeper in shearbladed areas compared to unmanaged forest. These findings indicate

  13. Fuel reduction in residential and scenic forests: A comparison of three treatments in a western Montana ponderosa pine stand

    Treesearch

    Joe H. Scott

    1998-01-01

    Three contrasting thinning treatments to reduce fire hazard were implemented in a 100-year-old ponderosa pine/Douglas-fir (Pinus ponderosa/Pseudotsuga menzesii) stand on the Lolo National Forest, MT. All treatments included a commercial thinning designed to reduce crown fuels and provide revenue to offset costs. The treatments are...

  14. Predicting breeding bird occurrence by stand- and microhabitat-scale features in even-aged stands in the Central Appalachians

    USGS Publications Warehouse

    McDermott, M.E.; Wood, P.B.; Miller, G.W.; Simpson, B.T.

    2011-01-01

    Spatial scale is an important consideration when managing forest wildlife habitat, and models can be used to improve our understanding of these habitats at relevant scales. Our objectives were to determine whether stand- or microhabitat-scale variables better predicted bird metrics (diversity, species presence, and abundance) and to examine breeding bird response to clearcut size and age in a highly forested landscape. In 2004-2007, vegetation data were collected from 62 even-aged stands that were 3.6-34.6. ha in size and harvested in 1963-1990 on the Monongahela National Forest, WV, USA. In 2005-2007, we also surveyed birds at vegetation plots. We used classification and regression trees to model breeding bird habitat use with a suite of stand and microhabitat variables. Among stand variables, elevation, stand age, and stand size were most commonly retained as important variables in guild and species models. Among microhabitat variables, medium-sized tree density and tree species diversity most commonly predicted bird presence or abundance. Early successional and generalist bird presence, abundance, and diversity were better predicted by microhabitat variables than stand variables. Thus, more intensive field sampling may be required to predict habitat use for these species, and management may be needed at a finer scale. Conversely, stand-level variables had greater utility in predicting late-successional species occurrence and abundance; thus management decisions and modeling at this scale may be suitable in areas with a uniform landscape, such as our study area. Our study suggests that late-successional breeding bird diversity can be maximized long-term by including harvests >10. ha in size into our study area and by increasing tree diversity. Some harvesting will need to be incorporated regularly, because after 15 years, the study stands did not provide habitat for most early successional breeding specialists. ?? 2010 Elsevier B.V.

  15. Red-cockaded woodpecker male/female foraging differences in young forest stands.

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Franzreb, Kathleen, E.

    2010-07-01

    ABSTRACT The Red-cockaded Woodpecker (Picoides borealis) is an endangered species endemic to pine (Pinus spp.) forests of the southeastern United States. I examined Red-cockaded Woodpecker foraging behavior to learn if there were male/female differences at the Savannah River Site, South Carolina. The study was conducted in largely young forest stands (,50 years of age) in contrast to earlier foraging behavior studies that focused on more mature forest. The Redcockaded Woodpecker at the Savannah River site is intensively managed including monitoring, translocation, and installation of artificial cavity inserts for roosting and nesting. Over a 3-year period, 6,407 foraging observations covering sevenmore » woodpecker family groups were recorded during all seasons of the year and all times of day. The most striking differences occurred in foraging method (males usually scaled [45% of observations] and females mostly probed [47%]),substrate used (females had a stronger preference [93%] for the trunk than males [79%]), and foraging height from the ground (mean 6 SE foraging height was higher for males [11.1 6 0.5 m] than females [9.8 6 0.5 m]). Niche overlap between males and females was lowest for substrate (85.6%) and foraging height (87.8%), and highest for tree species (99.0%), tree condition (98.3%), and tree height (96.4%). Both males and females preferred to forage in older, large pine trees. The habitat available at the Savannah River Site was considerably younger than at most other locations, but the pattern of male/female habitat partitioning observed was similar to that documented elsewhere within the range attesting to the species’ ability to adjust behaviorally.« less

  16. Phytoparasitic Nematodes Adjacent to Established Strawberry Plantations

    PubMed Central

    Crow, R. V.; MacDonald, D. H.

    1978-01-01

    Plant-nematode populations associated with uncultivated vegetation, adjacent strawberry plants, and alternate crop sites were studied at three locations in Minnesota. At one site (Forest Lake), Paratylenchus projectus, Meloidogyne hapla, and Pratylenchus tenuis were frequently associated with the roots of native vegetation. These nematode species were also present in adjacent strawberry beds. Among alternate crops observed, oats and muskmelon usually supported the fewest nematodes although moderate densities of Xiphinema americanum and P. tenuis were found at one location in plots planted to oats. Pratylenchus tenuis was also found on rye at one location. PMID:19305841

  17. Do natural disturbances or the forestry practices that follow them convert forests to early-successional communities?

    PubMed

    Brewer, J Stephen; Bertz, Christine A; Cannon, Jeffery B; Chesser, Jason D; Maynard, Erynn E

    2012-03-01

    Stand-replacing natural disturbances in mature forests are traditionally seen as events that cause forests to revert to early stages of succession and maintain species diversity. In some cases, however, such transitions could be an artifact of salvage logging and may increase biotic homogenization. We present initial (two-year) results of a study of the effects of tornado damage and the combined effects of tornado damage and salvage logging on environmental conditions and ground cover plant communities in mixed oak-pine forests in north central Mississippi. Plots were established in salvage-logged areas, adjacent to plots established before the storm in unlogged areas, spanning a gradient of storm damage intensity. Vegetation change directly attributable to tornado damage was driven primarily by a reduction in canopy cover but was not consistent with a transition to an early stage of succession. Although we observed post-storm increases of several disturbance indicators (ruderals), we also observed significant increases in the abundance of a few species indicative of upland forests. Increases in flowering were just as likely to occur in species indicative of forests as in species indicative of open woodlands. Few species declined as a result of the tornado, resulting in a net increase in species richness. Ruderals were very abundant in salvage-logged areas, which contained significantly higher amounts of bare ground and greater variance in soil penetrability than did damaged areas that were not logged. In contrast to unlogged areas severely damaged by the tornado, most upland forest indicators were not abundant in logged areas. Several of the forest and open-woodland indicators that showed increased flowering in damaged areas were absent or sparse in logged areas. Species richness was lower in salvage-logged areas than in adjacent damaged areas but similar to that in undamaged areas. These results suggest that salvage logging prevented positive responses of several

  18. Highly stocked coniferous stands on the Olympic Peninsula: chemical composition and implications for harvest strategy. Forest Service research paper

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Little, S.N.; Waddell, D.R.

    1987-10-01

    This report presents an assessment of macronutrients and their distribution within highly stocked, stagnant stands of mixed conifers on the Quilcene Ranger District, Olympic National Forest, northwest Washington. These stands consisted of predominantly three species: western hemlock (Tsuga heterophylla), coast Douglas-fir (Pseudotsuga menzeisii), and western redcedar (Thuja plicata). Preliminary investigation suggests that the living crown contains a small portion of the nutrient capital on the site. Extracting this material from the site during harvest or site preparation should not pose a threat to future production of biomass. Bioassays suggested that no macronutrients were deficient for growth of Douglas-fir seedlings.

  19. Understanding ponderosa pine forest-grassland vegetation dynamics at Fort Valley Experimental Forest using phytolith analysis

    Treesearch

    Becky K. Kerns; Margaret M. Moore; Stephen C. Hart

    2008-01-01

    In the last century, ponderosa pine forests in the Southwest have changed from more open park-like stands of older trees to denser stands of younger, small-diameter trees. Considerable information exists regarding ponderosa pine forest fire history and recent shifts in stand structure and composition, yet quantitative studies investigating understory reference...

  20. Silvicultural rehabilitation of cutover mixedwood stands

    Treesearch

    Laura S. Kenefic; Mohammad Bataineh; Jeremy S. Wilson; John C. Brissette; Ralph D. Nyland

    2014-01-01

    We investigated rehabilitation of mixedwood stands degraded by exploitative cutting on the Penobscot Experimental Forest in Maine. Three precommercial rehabilitation treatments were applied: control (no rehabilitation), moderate rehabilitation (crop tree release [CTR]), and intensive rehabilitation (CTR, timber stand improvement [TSI], and red spruce fill planting)....

  1. Additive or non-additive effect of mixing oak in pine stands on soil properties depends on the tree species in Mediterranean forests.

    PubMed

    Brunel, Caroline; Gros, Raphael; Ziarelli, Fabio; Farnet Da Silva, Anne Marie

    2017-07-15

    This study investigated how oak abundance in pine stands (using relative Oak Basal Area %, OBA%) may modulate soil microbial functioning. Forests were composed of sclerophyllous species i.e. Quercus ilex mixed with Pinus halepensis Miller or of Q. pubescens mixed with P. sylvestris. We used a series of plots with OBA% ranging from 0 to 100% in the two types of stand (n=60) and both OLF and A-horizon compartments were analysed. Relations between OBA% and either soil chemical (C and N contents, quality of organic matter via solid-state NMR, pH, CaCO 3 ) or microbial (enzyme activities, basal respiration, biomass and catabolic diversity via BIOLOG) characteristics were described. OBA% increase led to a decrease in the recalcitrant fraction of organic matter (OM) in OLF and promoted microbial growth. Catabolic profiles of microbial communities from A-horizon were significantly modulated in Q. ilex and P. halepensis stand by OBA% and alkyl C to carboxyl C ratio (characteristic of cutin from Q. ilex tissues) and in Q. pubescens and P. sylvestris stands, by OBA% and pH. In A-horizon under Q. ilex and P. halepensis stands, linear regressions were found between catabolic diversity, microbial biomass and OBA% suggesting an additive effect. Conversely, in A-horizon Q. pubescens and P. sylvestris stands, the relationship between OBA% and either cellulase activities, polysaccharides or ammonium contents, suggested a non-additive effect of Q. pubescens and P. sylvestris, enhancing mineralization of the OM labile fraction for plots characterized by an OBA% ranging from 40% to 60%. Mixing oak with pine thus favored microbial dynamics in both type of stands though OBA% print varied with tree species and consequently sustainable soil functioning depend strongly on the composition of mixed stands. Our study indeed revealed that, when evaluating the benefits of forest mixed stand on soil microbial functioning and OM turnover, the identity of tree species has to be considered

  2. Converting partially-stocked aspen stands to fully-stocked stands in the Lake States: an economic analysis.

    Treesearch

    Jeffrey T. Olson; Allen L. Lundgren

    1978-01-01

    The 1968 Wisconsin Forest Survey showed large areas of aspen type that are not considered fully stocked. The economic feasibility of converting partially-stocked stands to full stocking is examined, and a rule presented for determining when a partially-stocked stand should be harvested to maximize its present value.

  3. Production and standing crop of litter and humus in a forest exposed to chronic gamma irradiation for twelve years

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Armentano, T.V.; Woodwell, G.M.

    Continuous exposure since 1961 of an oak-pine forest at Brookhaven National Laboratory to chronic gamma irradiation has shown: (1) progressive reduction in litter production from the first year through 1965; (2) greater litter production in 1973 compared to 1965 at exposure rates below 9 R/day primarily because of the prolific sprouting of the oaks, especially Quercus alba; (3) further reduction in litter production in intermediate zones (14-49 R/day) from 1965 to 1973 as a result of replacement of the forest by a Carex pensylvanica mat; (4) increased litter production in the high exposure zone (125 R/day) in 1973 as amore » result of colonization by adventive species; (5) reduction in the standing crop of litter by 1973 at the lowest exposure rate studied (3.5 R/day) although in 1965 there was no reduction at exposure rates up to 15 R/day; (6) decline in humus content at 4.6 R/day and above with the standing crop in the Carex zone exceeding that of the shrub and damaged forest zones of lower exposures. Both further losses and partial recovery in the production and storage of organic matter have occurred since 1965. These changes constitute a portion of the long-term response of the forest to chronic disturbance. The pattern of response is the result of ecosystem processes that are still not in equilibrium with the chronic disturbance and which were not predictable from short-term studies, even those spanning as much as 4 yr.« less

  4. Silvicultural systems for harvesting mixed hardwood stands

    Treesearch

    H. Clay Smith; Ivan L. Sander

    1989-01-01

    Mixed stands that include oaks, yellow-poplar, black cherry, maples, white ash, basswood, birches, American beech, and other species are commonly found in the central hardwood forest. Depending on site quality and past stand treatment, overstory composition may range from nearly pure stands of oak or yellow-poplar to mixtures of 20 or more species.

  5. Valuation of Forest Amenities: A Macro Approach

    Treesearch

    Ronald Raunikar; Joseph Buongiorno

    2001-01-01

    A method of estimating forest amenity value based on macroeconomic growth theory is presented. It relies on the assumption that more valuable forest amenities are provided by a forest with a more natural stand structure. We construct a forest naturalness index from stand data that provides a relative measure of the forest amenity provided regionally. This naturalness...

  6. A field test of point relascope sampling of down coarse woody material in managed stands in the Acadian Forest

    Treesearch

    John C. Brissette; Mark J. Ducey; Jeffrey H. Gove

    2003-01-01

    We field tested a new method for sampling down coarse woody material (CWM) using an angle gauge and compared it with the more traditional line intersect sampling (LIS) method. Permanent sample locations in stands managed with different silvicultural treatments within the Penobscot Experimental Forest (Maine, USA) were used as the sampling locations. Point relascope...

  7. A comparison of airborne evapotranspiration maps and sapflow measurements in oak and beech forest stands

    NASA Astrophysics Data System (ADS)

    Schlerf, M.; Mallick, K.; Hassler, S. K.; Blume, T.; Ronellenfitsch, F.; Gerhards, M.; Udelhoven, T.; Weiler, M.

    2017-12-01

    Accurate estimations of spatially explicit daily Evapotranspiration (ET) may help water managers quantifying the water requirements of agricultural crops or trees. Airborne remote sensing may provide suitable ET maps, but uncertainties need to be better understood. In this study we compared high spatial resolution remotely sensed ET maps for 7 July 2016 with sap flow measurements over 32 forest stands located in the Attert catchment, Luxembourg. Forest stands differed in terms of species (Quercus robur, Fagus sylvatica), geology (schist, marl, sandstone), and geomorphology (slope position, plain, valley). Within each plot, at 1-3 trees the sap flow velocity (cm per hour) was measured between 8 am and 8 pm in 10 min intervals and averaged into a single value per plot and converted into values of volume flux (litres per day). Remotely sensed ET maps were derived by integrating airborne thermal infrared (TIR) images with an analytical surface energy balance model, Surface Temperature Initiated Closure (STIC1.2, Mallick et al. 2016). Airborne TIR images were acquired under clear sky conditions at 9:12, 10:08, 13:56, 14:50, 15:54, and 18:41 local time using a hyperspectral-thermal instrument. Images were geometrically corrected, calibrated, mosaicked, and converted to surface radiometric temperature. Surface temperature maps in conjunction with meteorological measurements recorded in the forest plots (air temperature, global radiation, relative humidity) were used as input to STIC1.2, for simultaneously estimating ET, sensible heat flux as well as surface and aerodynamic conductances. Instantaneous maps of ET were converted into daily ET maps and compared with the sap flow measurements. Results reveal a significant correspondence between remote sensing and field measured ET. The differences in the magnitude of predicted versus observed ET was found to be associated the biophysical conductances, radiometric surface temperature, and ecohydrological characteristics of the

  8. Forest structure and downed woody debris in boreal, temperate, and tropical forest fragments.

    PubMed

    Gould, William A; González, Grizelle; Hudak, Andrew T; Hollingsworth, Teresa Nettleton; Hollingsworth, Jamie

    2008-12-01

    Forest fragmentation affects the heterogeneity of accumulated fuels by increasing the diversity of forest types and by increasing forest edges. This heterogeneity has implications in how we manage fuels, fire, and forests. Understanding the relative importance of fragmentation on woody biomass within a single climatic regime, and along climatic gradients, will improve our ability to manage forest fuels and predict fire behavior. In this study we assessed forest fuel characteristics in stands of differing moisture, i.e., dry and moist forests, structure, i.e., open canopy (typically younger) vs. closed canopy (typically older) stands, and size, i.e., small (10-14 ha), medium (33 to 60 ha), and large (100-240 ha) along a climatic gradient of boreal, temperate, and tropical forests. We measured duff, litter, fine and coarse woody debris, standing dead, and live biomass in a series of plots along a transect from outside the forest edge to the fragment interior. The goal was to determine how forest structure and fuel characteristics varied along this transect and whether this variation differed with temperature, moisture, structure, and fragment size. We found nonlinear relationships of coarse woody debris, fine woody debris, standing dead and live tree biomass with mean annual median temperature. Biomass for these variables was greatest in temperate sites. Forest floor fuels (duff and litter) had a linear relationship with temperature and biomass was greatest in boreal sites. In a five-way multivariate analysis of variance we found that temperature, moisture, and age/structure had significant effects on forest floor fuels, downed woody debris, and live tree biomass. Fragment size had an effect on forest floor fuels and live tree biomass. Distance from forest edge had significant effects for only a few subgroups sampled. With some exceptions edges were not distinguishable from interiors in terms of fuels.

  9. Wildland fire effects in silviculturally treated vs. untreated stands of New Mexico and Arizona

    Treesearch

    Douglas S. Cram; Terrell T. Baker; Jon C. Boren

    2006-01-01

    Stand-replacement fires, particularly in ponderosa pine (Pinus ponderosa) forests, have replaced highfrequency, low-intensity historical fire regimes. We examined whether forest stands treated recently using silvicultural practices would be (1) less susceptible to stand-replacing crownfires, and (2) more ecologically and functionally resilient...

  10. Bryophyte species associations with coarse woody debris and stand ages in Oregon

    USGS Publications Warehouse

    Rambo, T.; Muir, Patricia S.

    1998-01-01

    We quantified the relationships of 93 forest floor bryophyte species, including epiphytes from incorporated litterfall, to substrate and stand age in Pseudotsuga menziesii-Tsuga heterophylla stands at two sites in western Oregon. We used the method of Dufrêne and Legendre that combines a species' relative abundance and relative frequency, to calculate that species' importance in relation to environmental variables. The resulting "indicator value" describes a species' reliability for indicating the given environmental parameter. Thirty-nine species were indicative of either humus, a decay class of coarse woody debris, or stand age. Bryophyte community composition changed along the continuum of coarse woody debris decomposition from recently fallen trees with intact bark to forest floor humus. Richness of forest floor bryophytes will be enhanced when a full range of coarse woody debris decay classes is present. A suite of bryophytes indicated old-growth forest. These were mainly either epiphytes associated with older conifers or liverworts associated with coarse woody debris. Hardwood-associated epiphytes mainly indicated young stands. Mature conifers, hardwoods, and coarse woody debris are biological legacies that can be protected when thinning managed stands to foster habitat complexity and biodiversity, consistent with an ecosystem approach to forest management.

  11. Environmental characteristics of the Grand Fir Mosaic and adjacent habitat types

    Treesearch

    Dennis E. Ferguson; John C. Byrne

    2000-01-01

    Grand Fir Mosaic habitats differ from adjacent forest habitats in their slow rate of secondary succession to woody vegetation. Remote monitoring stations were used to sample the environment at a Grand Fir Mosaic site and three adjacent habitat types. The Grand Fir Mosaic site has shorter growing seasons, cooler temperatures, and more soil moisture than the other sites...

  12. Methods for calculating forest ecosystem and harvested carbon with standard estimates for forest types of the United States

    Treesearch

    James E. Smith; Linda S. Heath; Kenneth E. Skog; Richard A. Birdsey

    2006-01-01

    This study presents techniques for calculating average net annual additions to carbon in forests and in forest products. Forest ecosystem carbon yield tables, representing stand-level merchantable volume and carbon pools as a function of stand age, were developed for 51 forest types within 10 regions of the United States. Separate tables were developed for...

  13. Detection of spatio-temporal changes of Norway spruce forest stands in Ore Mountains using airborne hyperspectral imagery

    NASA Astrophysics Data System (ADS)

    Misurec, J.; Kopačková, V.; Lhotáková, Z.; Albrechtova, J.; Campbell, P. K. E.

    2015-12-01

    The Ore Mountains are an example of the region that suffered from severe environmental pollution caused by long-term coal mining and heavy industry leading to massive dieback of the local Norway spruce forests between the 1970's and 1990's. The situation became getting better at the end of 1990's after pollution loads significantly decreased. In 1998 and 2013, airborne hyperspectral data (with sensor ASAS and APEX, respectively) were used to study recovery of the originally damaged forest stands and compared them with those that have been less affected by environmental pollution. The field campaign (needle biochemical analysis, tree defoliation etc.) accompanied hyperspectral imagery acquisition. An analysis was conducted assessing a set of 16 vegetation indices providing complex information on foliage, biochemistry and canopy biophysics and structure. Five of them (NDVI, NDVI705, VOG1, MSR and TCARI/OSAVI) showing the best results were employed to study spatial gradients as well as temporal changes. The detected gradients are in accordance with ground truth data on representative trees. The obtained results indicate that the original significant differences between the damaged and undamaged stands have been generally levelled until 2013, although it is still possible to detect signs of the previous damages in several cases.

  14. Productivity of aboveground coarse wood biomass and stand age related to soil hydrology of Amazonian forests in the Purus-Madeira interfluvial area

    NASA Astrophysics Data System (ADS)

    Cintra, B. B. L.; Schietti, J.; Emillio, T.; Martins, D.; Moulatlet, G.; Souza, P.; Levis, C.; Quesada, C. A.; Schöngart, J.

    2013-04-01

    The ongoing demand for information on forest productivity has increased the number of permanent monitoring plots across the Amazon. Those plots, however, do not comprise the whole diversity of forest types in the Amazon. The complex effects of soil, climate and hydrology on the productivity of seasonally waterlogged interfluvial wetland forests are still poorly understood. The presented study is the first field-based estimate for tree ages and wood biomass productivity in the vast interfluvial region between the Purus and Madeira rivers. We estimate stand age and wood biomass productivity by a combination of tree-ring data and allometric equations for biomass stocks of eight plots distributed along 600 km in the Purus-Madeira interfluvial area that is crossed by the BR-319 highway. We relate stand age and wood biomass productivity to hydrological and edaphic conditions. Mean productivity and stand age were 5.6 ± 1.1 Mg ha-1 yr-1 and 102 ± 18 yr, respectively. There is a strong relationship between tree age and diameter, as well as between mean diameter increment and mean wood density within a plot. Regarding the soil hydromorphic properties we find a positive correlation with wood biomass productivity and a negative relationship with stand age. Productivity also shows a positive correlation with the superficial phosphorus concentration. In addition, superficial phosphorus concentration increases with enhanced soil hydromorphic condition. We raise three hypotheses to explain these results: (1) the reduction of iron molecules on the saturated soils with plinthite layers close to the surface releases available phosphorous for the plants; (2) the poor structure of the saturated soils creates an environmental filter selecting tree species of faster growth rates and shorter life spans and (3) plant growth on saturated soil is favored during the dry season, since there should be low restrictions for soil water availability.

  15. Mite communities (Acari: Mesostigmata) in young and mature coniferous forests after surface wildfire.

    PubMed

    Kamczyc, Jacek; Urbanowski, Cezary; Pers-Kamczyc, Emilia

    2017-06-01

    Density, diversity and assemblage structure of Mesostigmata (cohorts Gamasina and Uropodina) were investigated in Scots pine forests differing in forest age (young: 9-40 years and mature: 83-101 years) in which wildfire occurred. This animal group belongs to the dominant acarine predators playing a crucial role in soil food webs and being important as biological control agents. In total, six forests (three within young and three within mature stands) were inspected in Puszcza Knyszyńska Forest Complex in May 2015. At each forest area, sampling was done from burned and adjacent control sites with steel cylinders for heat extraction of soil fauna. Data were analyzed statistically with nested ANOVA. We found a significant effect on mite density of both fire and forest age, with more mites in mature forests and control plots. In total, 36 mite taxa were identified. Mite diversity differed significantly between forest ages but not between burned versus control. Our study indicated that all studied forests are characterized by unique mite species and that the mite communities are dominated by different mite species depending on age forest and surface wildfire occurrence. Finally, canonical correspondence analysis ranked the mite assemblages from control mature, through burned young and burned mature, away from the control young.

  16. Spatial Interactions in Multiple-Use Forestry and Substitution and Wealth Effects for the Single Stand

    Treesearch

    Stephen K. Swallow; David N. Wear

    1993-01-01

    Forestry models often ignore spatial relationships between forest stands. This paper isolates the effects of stand interactions in muitiple-use forestry through a straightforward extension of the single-stand model. Effects of stand interactions decompose into wealth and substitution effects and may cause time-varying patterns of resource use for a forest...

  17. The impact of a large boreal wildfire on boundary-layer conditions and carbon cycling in adjacent unburned areas: case study of the 2011 Utikuma Complex fire, Alberta, Canada

    NASA Astrophysics Data System (ADS)

    Petrone, R. M.; Thompson, D. K.; Chasmer, L.; Kljun, N.; Flannigan, M.; Devito, K. J.; Waddington, J. M.

    2016-12-01

    Boreal wildfire conflagrations have increased in frequency in the western boreal forest of Canada, with notable events in 2011, 2015, and 2016. Significant advances have been made in recent years in understanding fire-atmosphere interactions, with similar gains in the knowledge of carbon emissions and post-fire carbon cycling in forests. However, the focus of such studies is routinely on the burned stands themselves, with little attention to the adjacent forest whose boundary layer meteorology and carbon cycling may be impacted by smoke plume. We capitalize here on opportunistic eddy covariance observations of boundary-layer conditions and carbon cycling taken over a long-term monitoring site adjacent to an active wildfire in Alberta, Canada in 2011. Over a one-week period while the wildfire was burning near the footprint of the tower the turbulent structure of the boundary layer near the tower was altered with significant changes in friction velocity, air temperature, and vapour pressure deficit. Moreover, growing season net ecosystem productivity (NEP) decreased to almost zero largely due to reduced photosynthesis likely due to smoke-related reductions in photosynthetically active radiation (PAR). While the `smoke event' caused a reduction in forest CO2 sequestration by 7 g CO2 m-2 given that the smoked affected area was 120 times greater than the area burned this carbon reduction was equivalent to 30% of gross fire emissions from the fire. Consequently, we argue that smoke related inhibition of photosynthesis via reduced light should be considered when investigating the net radiative forcing of boreal forest wildfires.

  18. Understanding ponderosa pine forest-grassland vegetation dynamics at Fort Valley Experimental Forest using phytolith analysis (P-53)

    Treesearch

    Becky K. Kerns; Margaret M. Moore; Stephen C. Hart

    2008-01-01

    In the last century, ponderosa pine forests in the Southwest have changed from more open park-like stands of older trees to denser stands of younger, smalldiameter trees. Considerable information exists regarding ponderosa pine forest fire history and recent shifts in stand structure and composition, yet quantitative studies investigating understory reference...

  19. An analytical model of stand dynamics as a function of tree growth, mortality and recruitment: the shade tolerance-stand structure hypothesis revisited.

    PubMed

    Zavala, Miguel A; Angulo, Oscar; Bravo de la Parra, Rafael; López-Marcos, Juan C

    2007-02-07

    Light competition and interspecific differences in shade tolerance are considered key determinants of forest stand structure and dynamics. Specifically two main stand diameter distribution types as a function of shade tolerance have been proposed based on empirical observations. All-aged stands of shade tolerant species tend to have steeply descending, monotonic diameter distributions (inverse J-shaped curves). Shade intolerant species in contrast typically exhibit normal (unimodal) tree diameter distributions due to high mortality rates of smaller suppressed trees. In this study we explore the generality of this hypothesis which implies a causal relationship between light competition or shade tolerance and stand structure. For this purpose we formulate a partial differential equation system of stand dynamics as a function of individual tree growth, recruitment and mortality which allows us to explore possible individual-based mechanisms--e.g. light competition-underlying observed patterns of stand structure--e.g. unimodal or inverse J-shaped equilibrium diameter curves. We find that contrary to expectations interspecific differences in growth patterns can result alone in any of the two diameter distributions types observed in the field. In particular, slow growing species can present unimodal equilibrium curves even in the absence of light competition. Moreover, light competition and shade intolerance evaluated both at the tree growth and mortality stages did not have a significant impact on stand structure that tended to converge systematically towards an inverse J-shaped curves for most tree growth scenarios. Realistic transient stand dynamics for even aged stands of shade intolerant species (unimodal curves) were only obtained when recruitment was completely suppressed, providing further evidence on the critical role played by juvenile stages of tree development (e.g. the sampling stage) on final forest structure and composition. The results also point out the

  20. Galling arthropod diversity in adjacent swamp forests and restinga vegetation in Rio Grande do Sul, Brazil.

    PubMed

    Mendonça, Milton De S; Piccardi, Hosana M F; Jahnke, Simone M; Dalbem, Ricardo V

    2010-01-01

    Galling arthropods create plant structures inside which they find shelter. Factors acting on galler diversity are still being discussed, with this fauna considered more diverse in xeric than mesic environments (higrothermic stress hypothesis, HSH), and also in more plant diverse sites. Here we compare galler abundance (N), equitability (E), species richness (S) and composition between adjacent restinga (xeric) and swamp forests (mesic) in Parque Estadual de Itapeva (29°21' S, 49°45' W), Rio Grande do Sul, southern Brazil. Five trails, two in swamp forest and three in restingas, were sampled four times each (January/December 2005). After an effort of 60h/person, 621 galled plant individuals belonging to 104 gall morphotypes were recorded. This suggests a high galler diversity for the Park, comparable to the richest places known. No differences were found for N, E or S between restingas and swamp forests. However, faunal composition differs significantly between the vegetation types. The dominant (most abundant) species are different in either vegetation type, and are rare or absent on the other vegetation type. Such species composition analysis is still largely ignored for gallers, and stresses the fact that the HSH cannot explain this pattern, since the latter is based on preferences by the ovipositing galler for xeric sites instead of mesic ones. The two habitats differ in microclimate, but species richness, as would be predicted by the HSH, does not differ. This small scale pattern can perhaps be attributed to biogeographic processes on larger scales, as suggested by the resource synchronisation hypothesis.

  1. Fire severity alters the distribution of pyrogenic carbon stocks across ecosystem pools in a Californian mixed-conifer forest

    NASA Astrophysics Data System (ADS)

    Maestrini, Bernardo; Alvey, Erin C.; Hurteau, Matthew D.; Safford, Hugh; Miesel, Jessica R.

    2017-09-01

    Pyrogenic carbon (PyC) is hypothesized to play an important role in the carbon (C) cycle due to its resistance to decomposition; however, much uncertainty still exists regarding the stocks of PyC that persist on-site after the initial erosion in postfire forests. Therefore, understanding how fire characteristics influence PyC stocks is vital, particularly in the context of California forests for which an increase of high-severity fires is predicted over the next decades. We measured forest C and persistent PyC stocks in areas burned by low-to-moderate and high-severity fire, as well as in adjacent unburned areas in a California mixed-conifer forest, 2 to 3 years after wildfire. We measured C and PyC stocks in the following compartments: standing trees, downed wood, forest floor, and mineral soil (0-5 cm), and we identified PyC using the weak nitric acid digestion method. We found that the total stock of PyC did not differ among fire severity classes (overall mean 248 ± 30 g C m-2); however, fire severity influenced the distribution of PyC in the individual compartments. Areas burned by high-severity fire had 2.5 times more PyC stocked in the coarse woody debris (p < 0.05), 3.3 times more PyC stocked in standing trees (p < 0.05), and a lower PyC stock in the forest floor (-22%, p < 0.05) compared to low-to-moderate fire severity areas. These results have important implications for the permanence time of PyC, which is putatively higher in standing trees and coarse woody debris compared to the forest floor, where it is susceptible to rapid losses through erosion.

  2. Influence of Human Pressure on Forest Resources and Productivity at Stand and Tree Scales: The Case Study of Yunnan Pine in SW China

    PubMed Central

    HINCKLEY, Thomas M.; CHI, Phillip; HAGMANN, Keala; HARRELL, Stevan; SCHMIDT, Amanda Henck; URGENSON, Lauren; ZENG, Zong-yong

    2015-01-01

    This paper examines human impact on stands and individual trees of Pinus yunnanensis growing near the small mountain villages of Pianshui and Yangjuan in southwestern Sichuan Province, China. In an effort to assess whether use of these forests was sustainable, we examined the effects of human use in two ways. First, we directly measured the effect of cutting branches, for fuel and fodder, on tree growth. We hypothesized that branch cutting would negatively impact tree growth. We established 12 plots on four hills and compared 14 pairs of trees, one tree in each pair with an apparently full crown and the other with a considerable portion of the crown removed. Second, we assessed stand and tree properties over a 500 m elevation gradient above the villages where we hypothesized that as elevation increases, stand and tree properties should show fewer human impacts. Although extensive branch cutting reduced the live crown, tree height and diameter, compensatory processes likely enabled trees to recover and to add basal area increments (BAIs) similar to those added by trees with full crowns. Trees and stands close to villages showed less growth and lower basal areas, respectively, than stands and trees at intermediate or distant elevations from villages. Areas relatively close to the villages showed considerable effects of human-related disturbances such as branch cutting, grazing, tree and shrub removal, losses of litter, and human and animal trails. Such areas had increased soil erosion and often loss of the ‘A’ horizon. Stands close to villages had younger trees, lower stand basal areas, smaller basal area increments, and more stumps. Our results suggest an increasingly vulnerable interface between occupants of these two villages and their surrounding forests. PMID:26478727

  3. Modeling biophysical properties of broad-leaved stands in the hyrcanian forests of Iran using fused airborne laser scanner data and ultraCam-D images

    NASA Astrophysics Data System (ADS)

    Mohammadi, Jahangir; Shataee, Shaban; Namiranian, Manochehr; Næsset, Erik

    2017-09-01

    Inventories of mixed broad-leaved forests of Iran mainly rely on terrestrial measurements. Due to rapid changes and disturbances and great complexity of the silvicultural systems of these multilayer forests, frequent repetition of conventional ground-based plot surveys is often cost prohibitive. Airborne laser scanning (ALS) and multispectral data offer an alternative or supplement to conventional inventories in the Hyrcanian forests of Iran. In this study, the capability of a combination of ALS and UltraCam-D data to model stand volume, tree density, and basal area using random forest (RF) algorithm was evaluated. Systematic sampling was applied to collect field plot data on a 150 m × 200 m sampling grid within a 1100 ha study area located at 36°38‧- 36°42‧N and 54°24‧-54°25‧E. A total of 308 circular plots (0.1 ha) were measured for calculation of stand volume, tree density, and basal area per hectare. For each plot, a set of variables was extracted from both ALS and multispectral data. The RF algorithm was used for modeling of the biophysical properties using ALS and UltraCam-D data separately and combined. The results showed that combining the ALS data and UltraCam-D images provided a slight increase in prediction accuracy compared to separate modeling. The RMSE as percentage of the mean, the mean difference between observed and predicted values, and standard deviation of the differences using a combination of ALS data and UltraCam-D images in an independent validation at 0.1-ha plot level were 31.7%, 1.1%, and 84 m3 ha-1 for stand volume; 27.2%, 0.86%, and 6.5 m2 ha-1 for basal area, and 35.8%, -4.6%, and 77.9 n ha-1 for tree density, respectively. Based on the results, we conclude that fusion of ALS and UltraCam-D data may be useful for modeling of stand volume, basal area, and tree density and thus gain insights into structural characteristics in the complex Hyrcanian forests.

  4. Effect of species composition on carbon and nitrogen stocks in forest floor and mineral soil in Norway spruce and European beech mixed forests

    NASA Astrophysics Data System (ADS)

    Andivia, Enrique; Rolo, Víctor; Jonard, Mathieu; Formánek, Pavel; Ponette, Quentin

    2015-04-01

    Management of existing forests has been identified as the main strategy to enhance carbon sequestration and to mitigate the impact of climate change on forest ecosystems. In this direction, the conversion of Norway spruce monospecific stands into mixed stands by intermingling individuals of European beech is an ongoing trend in adaptive forest management strategies, especially in Central Europe. However, studies assessing the effect of changes in tree species composition on soil organic carbon (SOC) and nitrogen stocks are still scarce and there is a lack of scientific evidence supporting tree species selection as a feasible management option to mitigate the effects of predicted future climatic scenarios. We compared C and N stocks in the forest floor (litter and humus) and the top 10 cm of mineral soil in two monospecific stands of Norway spruce and European beech and in a mixed stand of both species. The effect of tree species composition on the C and N stocks and its spatial distribution was evaluated based on litterfall, root production, elevation and canopy opening, and by using a combination of modelling and geostatistical techniques. C stock was highest in the Norway spruce and the mixed stands, while N stock was highest in the mixed stand and lowest under European beech, with intermediate values in the Norway spruce stand. Each forest type showed differences in forest floor properties, suggesting that species composition is an important factor governing forest floor characteristics, including C and N stocks. The distribution of C and N stocks between forest soil layers was different for each forest type. C and N stocks were highest in the hummus layer under Norway spruce, whereas both stocks were lowest in the European beech stand. On the other hand, the mixed stand showed the highest C and N accumulation in the uppermost mineral soil layer, while the monospecific stands showed similar values. Litterfall was the main contribution to C and N stocks of the

  5. Influence of forest stands on soil and ecosystem carbon stocks in the conditions of the European part of Russia

    NASA Astrophysics Data System (ADS)

    Kaganov, Vladimir

    2016-04-01

    Forest stands are one of the most important components of ecosystems, both in Russia and around the world and at the same time forest vegetation is able to provide environment-modifying effect on the occupied landscape and, in particular, on the soil cover. Currently, due to the large interest in the carbon cycle, there is a question about the influence of forest vegetation on carbon stocks in ecosystems and in particular in the soil cover. To perform the study we selected 9 objects located in the European part of Russia from the area of the southern taiga to the semi-desert zone: Novgorod region, Kostroma region, Moscow region (2 objects), Penza region, Voronezh region, Volgograd region (2 objects) and Astrakhan region. For studying the influence of forest vegetation on the soil`s carbon, we organized the following experiment scheme: in each of the objects two key sites were selected, so that they originally were in the same soil conditions and the difference between them was only in a course development of vegetation - forest or grass. One part of the experimental sites, presenting forest vegetation, were the restored forests on abandoned lands with the age of 70-200 years. The second part of the experimental sites were artificial forest plantations aged from 60 to 112 years planted on the originally treeless forest-steppe or steppe landscapes. Perennial hayfields, perennial abandoned agricultural landscapes and virgin steppe areas were used as reference sites with grass vegetation. For each forest site we estimated the major carbon pools: phytomass, mortmass (dead wood, dry grass), debris, litter and soil. All data were recalculated using the conversion factors in carbon stocks in t C ha-1. We collected soil samples every 10 cm until the depth of 50 cm, and then at 50-75 and 75-100 cm soil layers. Bulk density and total organic carbon were determined by CHN analyzer. As a result, the soil`s carbon was also calculated into t C ha-1. We found out that the total

  6. Effects of intermediate-severity disturbance on composition and structure in mixed Pinus-hardwood stands

    Treesearch

    Benjamin Trammell; Justin Hart; Callie Schweitzer; Daniel C. Dey; Michael Steinberg

    2017-01-01

    Increasingly, forest managers intend to create or maintain mixed Pinus-hardwood stands. This stand assemblage may be driven by a variety of objectives but is often motivated by the desire to enhance native forest diversity and promote resilience to perturbations. Documenting the effects of natural disturbances on species composition and stand...

  7. Carbon stocks across a chronosequence of thinned and unmanaged red pine (Pinus resinosa) stands

    USGS Publications Warehouse

    Powers, Matthew D.; Kolka, Randall K.; Bradford, John B.; Palik, Brian J.; Fraver, Shawn; Jurgensen, Martin F.

    2012-01-01

    Forests function as a major global C sink, and forest management strategies that maximize C stocks offer one possible means of mitigating the impacts of increasing anthropogenic CO2 emissions. We studied the effects of thinning, a common management technique in many forest types, on age-related trends in C stocks using a chronosequence of thinned and unmanaged red pine (Pinus resinosa) stands ranging from 9 to 306 years old. Live tree C stocks increased with age to a maximum near the middle of the chronosequence in unmanaged stands, and increased across the entire chronosequence in thinned stands. C in live understory vegetation and C in the mineral soil each declined rapidly with age in young stands but changed relatively little in middle-aged to older stands regardless of management. Forest floor C stocks increased with age in unmanaged stands, but forest floor C decreased with age after the onset of thinning around age 40 in thinned stands. Deadwood C was highly variable, but decreased with age in thinned stands. Total ecosystem C increased with stand age until approaching an asymptote around age 150. The increase in total ecosystem C was paralleled by an age-related increase in total aboveground C, but relatively little change in total belowground C. Thinning had surprisingly little impact on total ecosystem C stocks, but it did modestly alter age-related trends in total ecosystem C allocation between aboveground and belowground pools. In addition to characterizing the subtle differences in C dynamics between thinned and unmanaged stands, these results suggest that C accrual in red pine stands continues well beyond the 60–100 year management rotations typical for this system. Management plans that incorporate longer rotations and thinning in some stands could play an important role in maximizing C stocks in red pine forests while meeting other objectives including timber extraction, biodiversity conservation, restoration, and fuel reduction goals.

  8. Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics.

    PubMed

    Itter, Malcolm S; Finley, Andrew O; D'Amato, Anthony W; Foster, Jane R; Bradford, John B

    2017-06-01

    Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics-changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly

  9. Variable effects of climate on forest growth in relation to climate extremes, disturbance, and forest dynamics

    USGS Publications Warehouse

    Itter, Malcolm S.; Finley, Andrew O.; D'Amato, Anthony W.; Foster, Jane R.; Bradford, John B.

    2017-01-01

    Changes in the frequency, duration, and severity of climate extremes are forecast to occur under global climate change. The impacts of climate extremes on forest productivity and health remain difficult to predict due to potential interactions with disturbance events and forest dynamics—changes in forest stand composition, density, size and age structure over time. Such interactions may lead to non-linear forest growth responses to climate involving thresholds and lag effects. Understanding how forest dynamics influence growth responses to climate is particularly important given stand structure and composition can be modified through management to increase forest resistance and resilience to climate change. To inform such adaptive management, we develop a hierarchical Bayesian state space model in which climate effects on tree growth are allowed to vary over time and in relation to past climate extremes, disturbance events, and forest dynamics. The model is an important step toward integrating disturbance and forest dynamics into predictions of forest growth responses to climate extremes. We apply the model to a dendrochronology data set from forest stands of varying composition, structure, and development stage in northeastern Minnesota that have experienced extreme climate years and forest tent caterpillar defoliation events. Mean forest growth was most sensitive to water balance variables representing climatic water deficit. Forest growth responses to water deficit were partitioned into responses driven by climatic threshold exceedances and interactions with insect defoliation. Forest growth was both resistant and resilient to climate extremes with the majority of forest growth responses occurring after multiple climatic threshold exceedances across seasons and years. Interactions between climate and disturbance were observed in a subset of years with insect defoliation increasing forest growth sensitivity to water availability. Forest growth was particularly

  10. Ecosystem management, forest health, and silviculture

    Treesearch

    Merrill R. Kaufmann; Claudia M. Regan

    1995-01-01

    Forest health issues include the effects of fire suppression and grazing on forest stands, reduction in amount of old-growth forests, stand structural changes associated with even-aged management, .changes in structure of the landscape mosaic, loss of habitat for threatened species, and the introduction of exotic species. The consequences of these impacts can be...

  11. Comparison of forest edge effects on throughfall deposition in different forest types.

    PubMed

    Wuyts, Karen; De Schrijver, An; Staelens, Jeroen; Gielis, Leen; Vandenbruwane, Jeroen; Verheyen, Kris

    2008-12-01

    This study examined the influence of distance to the forest edge, forest type, and time on Cl-, SO4(2-), NO3(-), and NH4+ throughfall deposition in forest edges. The forests were dominated by pedunculate oak, silver birch, or Corsican/Austrian pine, and were situated in two regions of Flanders (Belgium). Along transects, throughfall deposition was monitored at distances of 0-128 m from the forest edge. A repeated-measures analysis demonstrated that time, forest type, and distance to the forest edge significantly influenced throughfall deposition of the ions studied. The effect of distance to the forest edge depended significantly on forest type in the deposition of Cl-, SO4(2-), and NO3(-): the edge effect was significantly greater in pine stands than in deciduous birch and oak stands. This finding supports the possibility of converting pine plantations into oak or birch forests in order to mitigate the input of nitrogen and potentially acidifying deposition.

  12. Modelling diameter distributions of two-cohort forest stands with various proportions of dominant species: a two-component mixture model approach.

    Treesearch

    Rafal Podlaski; Francis Roesch

    2014-01-01

    In recent years finite-mixture models have been employed to approximate and model empirical diameter at breast height (DBH) distributions. We used two-component mixtures of either the Weibull distribution or the gamma distribution for describing the DBH distributions of mixed-species, two-cohort forest stands, to analyse the relationships between the DBH components,...

  13. Tree hole mosquito species composition and relative abundances differ between urban and adjacent forest habitats in northwestern Argentina.

    PubMed

    Mangudo, C; Aparicio, J P; Rossi, G C; Gleiser, R M

    2018-04-01

    Water-holding tree holes are main larval habitats for many pathogen vectors, especially mosquitoes (Diptera: Culicidae). Along 3 years, the diversity and composition of mosquito species in tree holes of two neighbouring but completely different environments, a city and its adjacent forest, were compared using generalized linear mixed models, PERMANOVA, SIMPER and species association indexes. The city area (Northwest Argentina) is highly relevant epidemiologically due to the presence of Aedes aegypti L. (main dengue vector) and occurrence of dengue outbreaks; the Yungas rainforests are highly biologically diverse. In total seven mosquito species were recorded, in descending order of abundance: Ae. aegypti, Haemagogus spegazzinii Brèthes, Sabethes purpureus (Theobald), Toxorhynchites guadeloupensis Dyar and Knab, Aedes terrens Walker, Haemagogus leucocelaenus Dyar & Shannon and Sabethes petrocchiae (Shannon and Del Ponte). The seven mosquito species were recorded in both city sites and forested areas; however, their mosquito communities significantly diverged because of marked differences in the frequency and relative abundance of some species: Tx. guadeloupensis and Ae. aegypti were significantly more abundant in forest and urban areas, respectively. Positive significant associations were detected between Ae. aegypti, Hg. spegazzinii and Hg. leucocelaenus. The combined presence of Ae. aegypti, Haemagogus and Sabethes in the area also highlight a potential risk of yellow fever epidemics. Overall results show an impoverished tree hole mosquito fauna in urban environments, reflecting negative effects of urbanization on mosquito diversity.

  14. Managing mature, even-aged stands

    Treesearch

    Ivan L. Sander; H. Clay Smith

    1989-01-01

    Foresters generally consider central hardwood stands mature when they are 80 to 100 years old or have reached a specified rotation age. However, by the time stands are 50 to 60 years old and in the large pole/small sawtimber size, they have generally slowed in height growth, their annual basal area growth has leveled off, and except for size, they have many of the...

  15. Stand-volume estimation from multi-source data for coppiced and high forest Eucalyptus spp. silvicultural systems in KwaZulu-Natal, South Africa

    NASA Astrophysics Data System (ADS)

    Dube, Timothy; Sibanda, Mbulisi; Shoko, Cletah; Mutanga, Onisimo

    2017-10-01

    Forest stand volume is one of the crucial stand parameters, which influences the ability of these forests to provide ecosystem goods and services. This study thus aimed at examining the potential of integrating multispectral SPOT 5 image, with ancillary data (forest age and rainfall metrics) in estimating stand volume between coppiced and planted Eucalyptus spp. in KwaZulu-Natal, South Africa. To achieve this objective, Partial Least Squares Regression (PLSR) algorithm was used. The PLSR algorithm was implemented by applying three tier analysis stages: stage I: using ancillary data as an independent dataset, stage II: SPOT 5 spectral bands as an independent dataset and stage III: combined SPOT 5 spectral bands and ancillary data. The results of the study showed that the use of an independent ancillary dataset better explained the volume of Eucalyptus spp. growing from coppices (adjusted R2 (R2Adj) = 0.54, RMSEP = 44.08 m3/ha), when compared with those that were planted (R2Adj = 0.43, RMSEP = 53.29 m3/ha). Similar results were also observed when SPOT 5 spectral bands were applied as an independent dataset, whereas improved volume estimates were produced when using combined dataset. For instance, planted Eucalyptus spp. were better predicted adjusted R2 (R2Adj) = 0.77, adjusted R2Adj = 0.59, RMSEP = 36.02 m3/ha) when compared with those that grow from coppices (R2 = 0.76, R2Adj = 0.46, RMSEP = 40.63 m3/ha). Overall, the findings of this study demonstrated the relevance of multi-source data in ecosystems modelling.

  16. Sampling and modeling visual component dynamics of forested areas

    Treesearch

    Victor A. Rudis

    1990-01-01

    A scaling device and sample design have been employed to assess vegetative screening of forested stands as part of an extensive forest inventory.Referenced in a poster presentation are results from East Texas pine and oak-pine stands and Alabama forested areas.Refinements for optimizing measures to distinguish differences in scenic beauty, disturbances, and stand...

  17. Matrix Intensification Alters Avian Functional Group Composition in Adjacent Rainforest Fragments

    PubMed Central

    Deikumah, Justus P.; McAlpine, Clive A.; Maron, Martine

    2013-01-01

    Conversion of farmland land-use matrices to surface mining is an increasing threat to the habitat quality of forest remnants and their constituent biota, with consequences for ecosystem functionality. We evaluated the effects of matrix type on bird community composition and the abundance and evenness within avian functional groups in south-west Ghana. We hypothesized that surface mining near remnants may result in a shift in functional composition of avifaunal communities, potentially disrupting ecological processes within tropical forest ecosystems. Matrix intensification and proximity to the remnant edge strongly influenced the abundance of members of several functional guilds. Obligate frugivores, strict terrestrial insectivores, lower and upper strata birds, and insect gleaners were most negatively affected by adjacent mining matrices, suggesting certain ecosystem processes such as seed dispersal may be disrupted by landscape change in this region. Evenness of these functional guilds was also lower in remnants adjacent to surface mining, regardless of the distance from remnant edge, with the exception of strict terrestrial insectivores. These shifts suggest matrix intensification can influence avian functional group composition and related ecosystem-level processes in adjacent forest remnants. The management of matrix habitat quality near and within mine concessions is important for improving efforts to preserveavian biodiversity in landscapes undergoing intensification such as through increased surface mining. PMID:24058634

  18. Matrix intensification alters avian functional group composition in adjacent rainforest fragments.

    PubMed

    Deikumah, Justus P; McAlpine, Clive A; Maron, Martine

    2013-01-01

    Conversion of farmland land-use matrices to surface mining is an increasing threat to the habitat quality of forest remnants and their constituent biota, with consequences for ecosystem functionality. We evaluated the effects of matrix type on bird community composition and the abundance and evenness within avian functional groups in south-west Ghana. We hypothesized that surface mining near remnants may result in a shift in functional composition of avifaunal communities, potentially disrupting ecological processes within tropical forest ecosystems. Matrix intensification and proximity to the remnant edge strongly influenced the abundance of members of several functional guilds. Obligate frugivores, strict terrestrial insectivores, lower and upper strata birds, and insect gleaners were most negatively affected by adjacent mining matrices, suggesting certain ecosystem processes such as seed dispersal may be disrupted by landscape change in this region. Evenness of these functional guilds was also lower in remnants adjacent to surface mining, regardless of the distance from remnant edge, with the exception of strict terrestrial insectivores. These shifts suggest matrix intensification can influence avian functional group composition and related ecosystem-level processes in adjacent forest remnants. The management of matrix habitat quality near and within mine concessions is important for improving efforts to preserveavian biodiversity in landscapes undergoing intensification such as through increased surface mining.

  19. Updating stand-level forest inventories using airborne laser scanning and Landsat time series data

    NASA Astrophysics Data System (ADS)

    Bolton, Douglas K.; White, Joanne C.; Wulder, Michael A.; Coops, Nicholas C.; Hermosilla, Txomin; Yuan, Xiaoping

    2018-04-01

    Vertical forest structure can be mapped over large areas by combining samples of airborne laser scanning (ALS) data with wall-to-wall spatial data, such as Landsat imagery. Here, we use samples of ALS data and Landsat time-series metrics to produce estimates of top height, basal area, and net stem volume for two timber supply areas near Kamloops, British Columbia, Canada, using an imputation approach. Both single-year and time series metrics were calculated from annual, gap-free Landsat reflectance composites representing 1984-2014. Metrics included long-term means of vegetation indices, as well as measures of the variance and slope of the indices through time. Terrain metrics, generated from a 30 m digital elevation model, were also included as predictors. We found that imputation models improved with the inclusion of Landsat time series metrics when compared to single-year Landsat metrics (relative RMSE decreased from 22.8% to 16.5% for top height, from 32.1% to 23.3% for basal area, and from 45.6% to 34.1% for net stem volume). Landsat metrics that characterized 30-years of stand history resulted in more accurate models (for all three structural attributes) than Landsat metrics that characterized only the most recent 10 or 20 years of stand history. To test model transferability, we compared imputed attributes against ALS-based estimates in nearby forest blocks (>150,000 ha) that were not included in model training or testing. Landsat-imputed attributes correlated strongly to ALS-based estimates in these blocks (R2 = 0.62 and relative RMSE = 13.1% for top height, R2 = 0.75 and relative RMSE = 17.8% for basal area, and R2 = 0.67 and relative RMSE = 26.5% for net stem volume), indicating model transferability. These findings suggest that in areas containing spatially-limited ALS data acquisitions, imputation models, and Landsat time series and terrain metrics can be effectively used to produce wall-to-wall estimates of key inventory attributes, providing an

  20. Alabama's Forests, 2005

    Treesearch

    Andrew J. Hartsell; Tony G. Johnson

    2009-01-01

    The principle findings of the eighth forest survey of Alabama (2005) and changes that have occurred since the previous surveys are presented. Topics examined include forest area, ownership, forest-type groups, stand structure, basal area, timber volume, growth removals, and mortality.

  1. Alabama's forests, 2000

    Treesearch

    Andrew J. Hartsell; Tony G. Johnson

    2009-01-01

    The principle findings of the seventh forest survey of Alabama (2000) and changes that have occurred since the previous surveys are presented. Topics examined include forest area, ownership, forest-type groups, stand structure, basal area, timber volume, growth, removals, and mortality.

  2. Detection of dead standing Eucalyptus camaldulensis without tree delineation for managing biodiversity in native Australian forest

    NASA Astrophysics Data System (ADS)

    Miltiadou, Milto; Campbell, Neil D. F.; Gonzalez Aracil, Susana; Brown, Tony; Grant, Michael G.

    2018-05-01

    In Australia, many birds and arboreal animals use hollows for shelters, but studies predict shortage of hollows in near future. Aged dead trees are more likely to contain hollows and therefore automated detection of them plays a substantial role in preserving biodiversity and consequently maintaining a resilient ecosystem. For this purpose full-waveform LiDAR data were acquired from a native Eucalypt forest in Southern Australia. The structure of the forest significantly varies in terms of tree density, age and height. Additionally, Eucalyptus camaldulensis have multiple trunk splits making tree delineation very challenging. For that reason, this paper investigates automated detection of dead standing Eucalyptus camaldulensis without tree delineation. It also presents the new feature of the open source software DASOS, which extracts features for 3D object detection in voxelised FW LiDAR. A random forest classifier, a weighted-distance KNN algorithm and a seed growth algorithm are used to create a 2D probabilistic field and to then predict potential positions of dead trees. It is shown that tree health assessment is possible without tree delineation but since it is a new research directions there are many improvements to be made.

  3. Direct vs. Microclimate-Driven Effects of Tree Species Diversity on Litter Decomposition in Young Subtropical Forest Stands.

    PubMed

    Seidelmann, Katrin N; Scherer-Lorenzen, Michael; Niklaus, Pascal A

    2016-01-01

    Effects of tree species diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy tree species richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with tree communities ranging from monocultures to mixtures of 24 native subtropical tree species. Litter bags filled with senescent leaves of three native tree species were placed from Nov. 2011 to Oct. 2012 on 134 plots along the tree species diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand species richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. Tree stands were 2-3 years old, but nevertheless tree species diversity explained more variation (54.3%) in decomposition than topography (7.7%). Tree species richness slowed litter decomposition, an effect that slightly depended on litter species identity. A large part of the variance in decomposition was explained by tree species composition, with the presence of three tree species playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, species diversity (without composition) explained 8.9% and topography 34.4% of

  4. Direct vs. Microclimate-Driven Effects of Tree Species Diversity on Litter Decomposition in Young Subtropical Forest Stands

    PubMed Central

    Seidelmann, Katrin N.; Scherer-Lorenzen, Michael; Niklaus, Pascal A.

    2016-01-01

    Effects of tree species diversity on decomposition can operate via a multitude of mechanism, including alterations of microclimate by the forest canopy. Studying such effects in natural settings is complicated by the fact that topography also affects microclimate and thus decomposition, so that effects of diversity are more difficult to isolate. Here, we quantified decomposition rates of standard litter in young subtropical forest stands, separating effects of canopy tree species richness and topography, and quantifying their direct and micro-climate-mediated components. Our litterbag study was carried out at two experimental sites of a biodiversity-ecosystem functioning field experiment in south-east China (BEF-China). The field sites display strong topographical heterogeneity and were planted with tree communities ranging from monocultures to mixtures of 24 native subtropical tree species. Litter bags filled with senescent leaves of three native tree species were placed from Nov. 2011 to Oct. 2012 on 134 plots along the tree species diversity gradient. Topographic features were measured for all and microclimate in a subset of plots. Stand species richness, topography and microclimate explained important fractions of the variations in litter decomposition rates, with diversity and topographic effects in part mediated by microclimatic changes. Tree stands were 2–3 years old, but nevertheless tree species diversity explained more variation (54.3%) in decomposition than topography (7.7%). Tree species richness slowed litter decomposition, an effect that slightly depended on litter species identity. A large part of the variance in decomposition was explained by tree species composition, with the presence of three tree species playing a significant role. Microclimate explained 31.4% of the variance in decomposition, and was related to lower soil moisture. Within this microclimate effect, species diversity (without composition) explained 8.9% and topography 34.4% of

  5. Treatment of an old-growth stand and its effects on birds, ants, and large woody debris: A case study. Forest Service general technical report

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bull, E.L.; Torgersen, T.R.; Blumton, A.K.

    1995-09-01

    An old-structure stand with large amounts of tree mortality was treated to accelerate regeneration and reduce fuel loads but still maintain its function as old growth for selected bird species. The smll-diameter (less than 15 inches in diameter at breast height (d.b.h.)), dead trees were removed as was some of the down wood less than 15 inches in diameter at the large end. All live trees of any size and all dead trees equal to or greater than 15 inches d.b.h. were retained. Vaux`s swifts (Chaetura vauxi) and pileated woodpeckers (Dryocopus pileatus) continued to use the stand after harvest formore » nesting and roosting. Brown-headed cowbirds (molothrus ater) were more than twice as common in the treated stand as in an adjacent unlogged, control stand. In a comparison before and after harvest in the treated stand, the number of logs increased, the number of logs with ants increased, but the percentage of logs with ants decreased.« less

  6. Response of old-growth conifers to reduction in stand density in western Oregon forests

    USGS Publications Warehouse

    Latham, P.; Tappeiner, J. C.

    2002-01-01

    The positive growth response of healthy young trees to density reduction is well known. In contrast, large old trees are usually thought to be intrinsically limited in their ability to respond to increased growing space; therefore, density reduction is seldom used in stands of old-growth trees. We tested the null hypothesis that old-growth trees are incapable of responding with increased growth following density reduction. The diameter growth response of 271 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), ponderosa pine (Pinus ponderosa Dougl. ex Laws) and sugar pine (Pinus lambertiana Dougl.) trees ranging in age from 158 to 650 years was examined 20 to 50 years after density reduction. Density reduction involved either light thinning with removal of less vigorous trees, or shelterwood treatments in which overstory trees were not removed. Ratios of basal area growth after treatment to basal area growth before treatment, and several other measures of growth, all indicated that the old trees sometimes benefited and were not harmed by density reduction. Growth increased by 10% or more for 68% of the trees in treated stands, and nearly 30% of trees increased growth by over 50%. This growth response persisted for at least 20 years. During this 20-year period, only three trees in treated stands (1.5%) exhibited a rapid decrease in growth, whereas growth decreased in 64% of trees in untreated stands. The length of time before a growth response to density reduction occurred varied from 5 to 25 years, with the greatest growth response often occurring 20 to 25 years after treatment. These results have important implications both for the basic biology of aging in woody plants as well as for silvicultural practices in forests with old-growth trees.

  7. Mortality in second-growth stands of the western white pine type

    Treesearch

    Richard F. Watt

    1954-01-01

    Foresters generally accept without alarm the normally small but continuing losses caused by the indigenous agents of mortality in forest stands. When a stand suffers a sudden increase in the rate of mortality, however, attention is focused upon the subject and a host of questions and speculative answers arise. How much growth is nullified by mortality during a rotation...

  8. How long do ponderosa pine snags stand?

    Treesearch

    Walter G. Dahms

    1949-01-01

    How long will the average ponderosa pine snag remain standing and thus contribute to greater rate of spread and resistance to control of forest fires? Are there any readily discernible characteristics that will enable us to predict which will fall soon and which will stand for a long time?

  9. Evaluation of the airborne imaging spectrometer for remote sensing of forest stand conditions

    NASA Technical Reports Server (NTRS)

    Olson, Charles E., Jr.

    1986-01-01

    Five pairs of plots were established in forest stands with one of each pair trenched and covered to prevent precipitation from reaching the tree roots. High winds and falling limbs destroyed the covers on three of the plots. The two remaining plots were in a red pine plantation and in a natural stand of sugar maple. Trees in both plots developed levels of moisture stress more than nine bars higher than control trees on the dates of overflights with the Airborne Imaging Spectrometer (AIS) and the Collins' Airborne Spectroradiometer (CAS). Hemispherical reflectance from stressed and control trees was measured with a Beckman DK2A spectrophotometer. On the day of the AIS overflight, stressed maple foliage was less reflective than the control from 1000 to 1300 nm, but more reflective at wavelengths longer than 1300 nm. Pine foliage was less reflective than the control from 1000 to 1600 nm, but the difference was small at wavelengths longer than 1350 nm. AIS data collected showed brightness values for both maple and pine to be lower than for the controls from 1000 to 1300 nm. CAS data were used to determine the gain in species identification accuracy obtainable with high spectral resolution data.

  10. Physiographic position, disturbance and species composition in North Carolina coastal plain forests

    Treesearch

    James G. Wyant; Ralph J. Alig; William A. Bechtold

    1991-01-01

    Relations among physiographic heterogeneity, disturbance and temporal change in forest composition were analyzed on 765 forest stands in the southern coastal plain of North Carolina. Physiographic position strongly restricted the species composition of forest stands, though broad overlap of some physiographic classes was noted. Forest stands in different physiographic...

  11. Carbon storage in old-growth forests of the Mid-Atlantic: toward better understanding the eastern forest carbon sink.

    PubMed

    McGarvey, Jennifer C; Thompson, Jonathan R; Epstein, Howard E; Shugart, Herman H

    2015-02-01

    Few old-growth stands remain in the matrix of secondary forests that dominates the eastern North American landscape. These remnant stands offer insight on the potential carbon (C) storage capacity of now-recovering secondary forests. We surveyed the remaining old-growth forests on sites characteristic of the general Mid-Atlantic United States and estimated the size of multiple components of forest C storage. Within and between old-growth stands, variability in C density is high and related to overstory tree species composition. The sites contain 219 ± 46 Mg C/ha (mean ± SD), including live and dead aboveground biomass, leaf litter, and the soil O horizon, with over 20% stored in downed wood and snags. Stands dominated by tulip poplar (Liriodendron tulipifera) store the most live biomass, while the mixed oak (Quercus spp.) stands overall store more dead wood. Total C density is 30% higher (154 Mg C/ha), and dead wood C density is 1800% higher (46 Mg C/ha) in the old-growth forests than in the surrounding younger forests (120 and 5 Mg C/ha, respectively). The high density of dead wood in old growth relative to secondary forests reflects a stark difference in historical land use and, possibly, the legacy of the local disturbance (e.g., disease) history. Our results demonstrate the potential for dead wood to maintain the sink capacity of secondary forests for many decades to come.

  12. [Correlations between standing trees trunk decay degree and soil physical-chemical properties in Korean pine-broadleaved mixed forest in Xiao Xing'an Mountains of Northeast China].

    PubMed

    Sun, Tian-Yong; Wang, Li-Hai; Sun, Mo-Long

    2013-07-01

    Standing trees decay often causes vast loss of timber resources. To investigate the correlations between the standing trees decay and the site conditions is of importance to scientifically and reasonably manage forests and to decrease wood resources loss. By using Resistograph and meter ruler, a measurement was made on the decay degree of the trunk near root and the diameter at breast height (DBH) of 15 mature Korean pine standing trees in a Korean pine-broadleaved mixed forest in Xiao Xing' an Mountains in May, 2011. In the meantime, soil samples were collected from the root zones of standing trees and the upslope and downslope 5 meters away from the trunks, respectively. Five physical-chemical properties including moisture content, bulk density, total porosity, pH value, and organic matter content of the soil samples were tested. The regression equations concerning the trunk decay degree of the standing trees, their DBH, and the 5 soil properties were established. The results showed that the trunk decay degree of the mature Korean pine standing trees had higher correlations with the bulk density, total porosity, pH value, and organic matter content (R = 0.687), and significant positive correlation with the moisture content (R = 0.507) of the soils at the root zones of standing trees, but less correlation with the 5 properties of the soils at both upslope and downslope 5 meters away from the trunks. The trunk decay degree was decreased when the soil moisture content was below 18.4%. No significant correlation was observed between the trunk decay degree of mature Korean pine standing trees and the tree age.

  13. Effects of stand and inter-specific stocking on maximizing standing tree carbon stocks in the eastern United States

    Treesearch

    Christopher W. Woodall; Anthony W. D' Amato; John B. Bradford; Andrew O. Finley

    2011-01-01

    There is expanding interest in management strategies that maximize forest carbon (C) storage to mitigate increased atmospheric carbon dioxide. The tremendous tree species diversity and range of stand stocking found across the eastern United States presents a challenge for determining optimal combinations for the maximization of standing tree C storage. Using a...

  14. Tree regeneration by seed in bottomland hardwood forests: A review

    USGS Publications Warehouse

    Kroschel, Whitney A.; King, Sammy L.; Keim, Richard F.

    2016-01-01

    Bottomland hardwood forests (BLH) are found in temperate, humid regions of the southeastern US, primarily on alluvial floodplains adjacent to rivers. Altered hydrology in rivers and floodplains has caused changes in stand development and species composition of BLHs. We hypothesize that the driving mechanisms behind these changes are related to the regeneration process because of the complexity of recruitment and the vulnerability of species at that age in development. Here we review the state of our understanding regarding BLH regeneration, and identify potential bottlenecks throughout the stages of seed production, seed dispersal, germination, establishment, and survival. Our process-level understanding of regeneration by seed in BLHs is rudimentary, thus limiting our ability to predict the effects of hydrologic alterations on species composition. By focusing future research on the appropriate stages of regeneration, we can better understand the sources of forest-community transitions across the diverse range of BLH systems.

  15. Atmospheric deposition in coniferous and deciduous tree stands in Poland

    NASA Astrophysics Data System (ADS)

    Kowalska, Anna; Astel, Aleksander; Boczoń, Andrzej; Polkowska, Żaneta

    2016-05-01

    The objective of this study was to assess the transformation of precipitation in terms of quantity and chemical composition following contact with the crown layer in tree stands with varied species composition, to investigate the effect of four predominant forest-forming species (pine, spruce, beech, and oak) on the amount and composition of precipitation reaching forest soils, and to determine the sources of pollution in atmospheric precipitation in forest areas in Poland. The amount and chemical composition (pH, electric conductivity, alkalinity, and chloride, nitrate, sulfate, phosphate, ammonium, calcium, magnesium, sodium, potassium, iron aluminum, manganese, zinc, copper, total nitrogen, and dissolved organic carbon contents) of atmospheric (bulk, BP) and throughfall (TF) precipitation were studied from January to December 2010 on twelve forest monitoring plots representative of Polish conditions. The study results provided the basis for the determination of the fluxes of pollutants in the forest areas of Poland and allowed the comparison of such fluxes with values provided in the literature for European forest areas. The transformation of precipitation in the canopy was compared for different tree stands. The fluxes of substances in an open field and under canopy were influenced by the location of the plot, including the regional meteorological conditions (precipitation amounts), vicinity of the sea (effect of marine aerosols), and local level of anthropogenic pollution. Differences between the plots were higher in TF than in BP. The impact of the vegetation cover on the chemical composition of precipitation depended on the region of the country and dominant species in a given tree stand. Coniferous species tended to cause acidification of precipitation, whereas deciduous species increased the pH of TF. Pine and oak stands enriched precipitation with components that leached from the canopy (potassium, manganese, magnesium) to a higher degree than spruce and

  16. Architectural plasticity in young Eucalyptus marginata on restored bauxite mines and adjacent natural forest in south-western Australia.

    PubMed

    Bleby, Timothy M; Colquhoun, Ian J; Adams, Mark A

    2009-08-01

    The aboveground architecture of Eucalyptus marginata (Jarrah) was investigated in chronosequences of young trees (2.5, 5 and 10 m height) growing in a seasonally dry climate in a natural forest environment with intact soils, and on adjacent restored bauxite mine sites on soils with highly modified A and B horizons above an intact C horizon. Compared to forest trees, trees on restored sites were much younger and faster growing, with straighter, more clearly defined main stems and deeper, narrower crowns containing a greater number of branches that were longer, thinner and more vertically angled. Trees on restored sites also had a higher fraction of biomass in leaves than forest trees, as indicated by 20-25% thicker leaves, 30-70% greater leaf area, 10-30% greater leaf area to sapwood area ratios and 5-30% lesser branch Huber values. Differences in crown architecture and biomass distribution were consistent with putatively greater soil-water, nutrient and light availability on restored sites. Our results demonstrate that under the same climatic conditions, E. marginata displays a high degree of plasticity of aboveground architecture in response to the net effects of resource availability and soil environment. These differences in architecture are likely to have functional consequences in relation to tree hydraulics and growth that, on larger scales, is likely to affect the water and carbon balances of restored forest ecosystems. This study highlights substrate as a significant determinant of tree architecture in water-limited environments. It further suggests that the architecture of young trees on restored sites may need to change again if they are to survive likely longer-term changes in resource availability.

  17. Humus characteristics and seasonal changes of soil arthropod communities in a natural sessile oak (Quercus petraea L.) stand and adjacent Austrian pine (Pinus nigra Arnold) plantation.

    PubMed

    Cakir, Meric; Makineci, Ender

    2013-11-01

    In order to assess the effects of conversion of natural stands into plantations, soil invertebrate micro- and macroarthropod communities were evaluated for their abundance and richness in a sessile oak (SO; Quercus petraea L.) stand and adjacent Austrian pine (AP; Pinus nigra Arnold) plantation. Sites were sampled four times a year in 3-month intervals from May 2009 to February 2010. Humus characteristics such as total mass; carbon, lignin, and cellulose contents; and C/N ratio were significantly different between SO and AP. Statistically significant differences were detected on soil pH, carbon and nitrogen contents, and electrical conductivity between the two sites. The number of microarthropods was higher in AP than in the SO site. The annual mean abundance values of microarthropods in a square meter were 67,763 in AP and 50,542 in SO, and the annual mean abundance values of macroarthropods were 921 m(-2) in AP and 427 m(-2) in SO. Among the soil microarthropods, Acari and Collembola were the dominant groups. Shannon's diversity index was more affected by evenness than species number despite the species diversity (H') of soil arthropods being generally higher in the SO stand. The abundance of microarthropods showed clear seasonal trends depending upon the humidity of the soil.

  18. Impact of professional foresters on timber harvests on West Virginia nonindustrial private forests

    Treesearch

    Stuart A. Moss; Eric Heitzman

    2013-01-01

    Timber harvests conducted on 90 nonindustrial private forest properties in West Virginia were investigated to determine the effects that professional foresters have on harvest and residual stand attributes. Harvests were classified based on the type of forester involved: (1) consulting/state service foresters representing landowners, (2) industry foresters representing...

  19. Stand-Damage Model with Java (Version 3.0)

    Treesearch

    George Racin; J.J. Colbert

    2004-01-01

    NOTE: Instructions for ordering the cd-rom with the software are included on the front cover of the linked publication. The Stand-Damage Model with Java is a distance-independent tree-growth simulator. The model follows the life of a forest stand represented by species and diameter-class widths. The user supplies the initial state of the stand along with management...

  20. Impacts of forest age on water use in Mountain ash forests

    USGS Publications Warehouse

    Wood, Stephen A.; Beringer, Jason; Hutley, Lindsay B.; McGuire, A. David; Van Dijk, Albert; Kilinc, Musa

    2008-01-01

    Runoff from mountain ash (Eucalyptus regnans F.Muell.) forested catchments has been shown to decline significantly in the few decades following fire returning to pre-fire levels in the following centuries owing to changes in ecosystem water use with stand age in a relationship known as Kuczera's model. We examined this relationship between catchment runoff and stand age by measuring whole-ecosystem exchanges of water using an eddy covariance system measuring forest evapotranspiration (ET) combined with sap-flow measurements of tree water use, with measurements made across a chronosequence of three sites (24, 80 and 296 years since fire). At the 296-year old site eddy covariance systems were installed above the E. regnans overstorey and above the distinct rainforest understorey. Contrary to predictions from the Kuczera curve, we found that measurements of whole-forest ET decreased by far less across stand age between 24 and 296 years. Although the overstorey tree water use declined by 1.8mmday-1 with increasing forest age (an annual decrease of 657mm) the understorey ET contributed between 1.2 and 1.5mmday-1, 45% of the total ET (3mmday-1) at the old growth forest.

  1. Proceedings: guidelines for regenerating Appalachian hardwood stands

    Treesearch

    H. Clay Smith; Arlyn W. Perkey; William E. Kidd

    1988-01-01

    This proceedings will provide field foresters and landowners with an update of current available information for regenerating Appalachian hardwood stands. We wanted a "state-of-the-art" proceedings for regenerating Appalachian hardwood stands. We asked the authors to make recommendations based on the current literature, their knowledge, and experience. Though...

  2. Higher climate warming sensitivity of Siberian larch in small than large forest islands in the fragmented Mongolian forest steppe.

    PubMed

    Khansaritoreh, Elmira; Dulamsuren, Choimaa; Klinge, Michael; Ariunbaatar, Tumurbaatar; Bat-Enerel, Banzragch; Batsaikhan, Ganbaatar; Ganbaatar, Kherlenchimeg; Saindovdon, Davaadorj; Yeruult, Yolk; Tsogtbaatar, Jamsran; Tuya, Daramragchaa; Leuschner, Christoph; Hauck, Markus

    2017-09-01

    Forest fragmentation has been found to affect biodiversity and ecosystem functioning in multiple ways. We asked whether forest size and isolation in fragmented woodlands influences the climate warming sensitivity of tree growth in the southern boreal forest of the Mongolian Larix sibirica forest steppe, a naturally fragmented woodland embedded in grassland, which is highly affected by warming, drought, and increasing anthropogenic forest destruction in recent time. We examined the influence of stand size and stand isolation on the growth performance of larch in forests of four different size classes located in a woodland-dominated forest-steppe area and small forest patches in a grassland-dominated area. We found increasing climate sensitivity and decreasing first-order autocorrelation of annual stemwood increment with decreasing stand size. Stemwood increment increased with previous year's June and August precipitation in the three smallest forest size classes, but not in the largest forests. In the grassland-dominated area, the tree growth dependence on summer rainfall was highest. Missing ring frequency has strongly increased since the 1970s in small, but not in large forests. In the grassland-dominated area, the increase was much greater than in the forest-dominated landscape. Forest regeneration decreased with decreasing stand size and was scarce or absent in the smallest forests. Our results suggest that the larch trees in small and isolated forest patches are far more susceptible to climate warming than in large continuous forests pointing to a grim future for the forests in this strongly warming region of the boreal forest that is also under high land use pressure. © 2017 John Wiley & Sons Ltd.

  3. Propagation of noise over and through a forest stand

    Treesearch

    Lee P. Herrington; C. Brock

    1977-01-01

    Measurements of the two-dimensional acoustic field in a forest resulting from a source located outside the forest indicated that the attenuation pattern near the ground is significantly different from the pattern higher up in the forest. The patterns of attenuation support the recent theory that the forest floor is the main absorber of acoustic energy in the forest....

  4. [Evapotranspiration characteristics of artificial and natural forests in Liupan Mountains of Ningxia, China during growth season].

    PubMed

    Cao, Gong-xiang; Wang, Xu-fang; Xiong, Wei; Wang, Yan-hui; Yu, Peng-tao; Wang, Yun-ni; Xu, Li-hong; Li, Zhen-hua

    2013-08-01

    In order to understand the effects of the structure of forest ecosystem on the hydrological processes, a comparative study by using thermal dissipation technique and hydrological methodology was made on the evapotranspiration (ET) and its components of Larix principis-rupprechtii plantation and Pinus armandi natural forest in two adjacent stands in a small catchment Xiangshuihe of Liupan Mountains during the growth season (May-October) in 2009. Throughout the growth season, the total ET from the plantation was 518.2 mm, which accounted for 104.6% of the precipitation and was much higher than that (420.5 mm) of the natural forest. The allocation of ET in the vertical layers performed similarly between the two stands, with the order of canopy layer > herb and soil layer > shrub layer, but the ratio of each component to total ET differed significantly. The plantation consumed 0.2 and 0.9 times more water for canopy interception (19.6 mm per month) and tree transpiration (25.2 mm per month) than the natural forest, respectively. However, the transpiration from the plantation was 4.4 mm per month, and took up 23.4% of the natural forest. In contrast, the sum of soil evaporation and herbage evapotranspiration consumed 37.1 mm water per month in the plantation, which was 0.8 times higher than that in the natural forest. The ET was calculated by Penman-Monteith equation to compare the results estimated by sap flow measurements, and the values estimated by the two methods were similar.

  5. Use of Fouler Transforms to define landscape scales of analysis for disturbances: A case study of thinned and unthinned forest stands

    Treesearch

    J. E. Lundquist; R. A. Sommerfeld

    2002-01-01

    Various disturbances such as disease and management practices cause canopy gaps that change patterns of forest stand structure. This study examined the usefulness of digital image analysis using aerial photos, Fourier Tranforms, and cluster analysis to investigate how different spatial statistics are affected by spatial scale. The specific aims were to: 1) evaluate how...

  6. Stand development and silviculture in bottomland hardwoods

    Treesearch

    J. Steven Meadows

    1993-01-01

    Silviculture for the production of high-quality timber in southern bottomland hardwood forests involves the application of environmentally sound practices in order to enhance the growth and quality of both individual trees and stands. To accomplish this purpose, silvicultural practices are typically used to regulate stand density, species composition, and stem quality...

  7. Effectiveness of management interventions on forest carbon stock in planted forests in Nepal.

    PubMed

    Dangal, Shambhu Prasad; Das, Abhoy Kumar; Paudel, Shyam Krishna

    2017-07-01

    Nepal has successfully established more than 370,000 ha of plantations, mostly with Pinus patula, in the last three and a half decades. However, intensive management of these planted forests is very limited. Despite the fact that the Kyoto Convention in 1997 recognized the role of plantations for forest-carbon sequestration, there is still limited knowledge on the effects of management practices and stand density on carbon-sequestration of popular plantation species (i.e. Pinus patula) in Nepal. We carried out case studies in four community forests planted between 1976 and 1990 to assess the impacts of management on forest carbon stocks. The study found that the average carbon stock in the pine plantations was 217 Mg C ha -1 , and was lower in forests with intensively managed plantations (214.3 Mg C ha -1 ) than in traditionally managed plantations (219 Mg C ha -1 ). However, it was the reverse in case of soil carbon, which was higher (78.65 Mg C ha -1 ) in the forests with intensive management. Though stand density was positively correlated with carbon stock, the proportionate increment in carbon stock was lower with increasing stand density, as carbon stock increased by less than 25% with a doubling of stand density (300-600). The total carbon stock was higher in plantations aged between 25 and 30 years compared to those aged between 30 and 35 years. Copyright © 2017 Elsevier Ltd. All rights reserved.

  8. Information system of forest growth and productivity by site quality type and elements of forest

    NASA Astrophysics Data System (ADS)

    Khlyustov, V.

    2012-04-01

    Information system of forest growth and productivity by site quality type and elements of forest V.K. Khlustov Head of the Forestry Department of Russian State Agrarian University named after K.A.Timiryazev doctor of agricultural sciences, professor The efficiency of forest management can be improved substantially by development and introduction of principally new models of forest growth and productivity dynamics based on regionalized site specific parameters. Therefore an innovative information system was developed. It describes the current state and gives a forecast for forest stand parameters: growth, structure, commercial and biological productivity depend on type of site quality. In contrast to existing yield tables, the new system has environmental basis: site quality type. The information system contains set of multivariate statistical models and can work at the level of individual trees or at the stand level. The system provides a graphical visualization, as well as export of the emulation results. The System is able to calculate detailed description of any forest stand based on five initial indicators: site quality type, site index, stocking, composition, and tree age by elements of the forest. The results of the model run are following parameters: average diameter and height, top height, number of trees, basal area, growing stock (total, commercial with distribution by size, firewood and residuals), live biomass (stem, bark, branches, foliage). The system also provides the distribution of mentioned above forest stand parameters by tree diameter classes. To predict the future forest stand dynamics the system require in addition the time slot only. Full set of forest parameters mention above will be provided by the System. The most conservative initial parameters (site quality type and site index) can be kept in the form of geo referenced polygons. In this case the system would need only 3 dynamic initial parameters (stocking, composition and age) to

  9. Arkansas’ forests, 2010

    Treesearch

    James F. Rosson; Anita K. Rose

    2015-01-01

    The principal findings of the ninth forest survey of Arkansas are presented. The survey examines trends between the 2005 and 2010 surveys. Topics examined include forest area, ownership, forest-type groups, stand structure, basal area, timber volume, growth, removals, mortality, crown characteristics, ozone levels, and invasive species.

  10. An Old-Growth Definition for Eastern Riverfront Forests

    Treesearch

    James S. Meadows; Gregory J. Nowacki

    1996-01-01

    Eastern riverfront forests fall into one of three types: (1) nearly pure eastern cottonwood stands, (2) nearly pure black willow stands, and (3) typical riverfront hardwood stands containing many species, but generally dominated by sycamore, pecan, green ash, sugarberry, and American elm. The eastern riverfront forest represents an intermediate successional stage...

  11. Hazard rating forest stands for gypsy moth

    Treesearch

    Ray R., Jr. Hicks

    1991-01-01

    A gypsy moth hazard exists when forest conditions prevail that are conducive to extensive damage from gypsy moth. Combining forest hazard rating with information on insect population trends provides the basis for predicting the probability (risk) of an event occurring. The likelihood of defoliation is termed susceptibility and the probability of damage (mortality,...

  12. View of Stand Pipe (Surge Tank) from FS 502. Looking ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    View of Stand Pipe (Surge Tank) from FS 502. Looking northeast - Childs-Irving Hydroelectric Project, Childs System, Stand Pipe (Surge Tank), Forest Service Road 708/502, Camp Verde, Yavapai County, AZ

  13. The relative density of forests in the United States

    Treesearch

    Christopher W. Woodall; Charles H. Perry; Patrick D. Miles

    2006-01-01

    A relative stand density assessment technique, using the mean specific gravity of all trees in a stand to predict its maximum stand density index (SDI) and subsequently its relative stand density (current SDI divided by maximum SDI), was used to estimate the relative density of forests across the United States using a national-scale forest inventory. Live tree biomass...

  14. Forest growth along a rainfall gradient in Hawaii: Acacia koa stand structure, productivity, foliar nutrients, and water- and nutrient-use efficiencies

    Treesearch

    Robin A. Harrington; James H. Fownes; Frederick C. Meinzer; Paul G. Scowcroft

    1995-01-01

    We tested whether variation in growth of native koa (Acacia koa) forest along a rainfall gradient was attributable to differences in leaf area index (LAI) or to differences in physiological performance per unit of leaf area. Koa stands were studied on western Kauai prior to Hurricane Iniki, and ranged from 500 to 1130 m elevation and from 850 to...

  15. Reducing CO2 emissions by managing for sudden oak death...is it possible?

    Treesearch

    Brendan Twieg; Yana Valachovic; Richard Cobb; Dan Stark

    2017-01-01

    Forest CO2 emissions, which have recently become a more regular concern in forest management, can radically increase following pest and disease outbreaks. We inventoried trees in a stand adjacent to an infested area in northern Humboldt County, California, and used a stand-level dynamic disease model to forecast Phythophthora ramorum...

  16. Fragmentation of forest communities in the eastern United States

    Treesearch

    Kurt Riitters; John Coulston; James Wickham

    2011-01-01

    Forest fragmentation threatens the sustainability of forest communities in the eastern United States. Forest communities exhibiting either a low total area or low percentage of intact forest are subject to relatively higher risk of shifts in stand composition towards edge-adapted and invasive species. Such changes in stand composition could result in local extirpation...

  17. Stocking, growth, and yield of birch stands

    Treesearch

    Dale S. Solomon; William B. Leak

    1969-01-01

    Intensive forest management depends heavily upon our ability to measure, control, and predict the growth, yield, or general development of timber stands, regardless of whether the management goal is for timber, aesthetics, recreation, water, or wildlife. A large amount of mensurational data about birch stands has been developed in recent years or synthesized from...

  18. Effects of Forest Disturbances on Forest Structural Parameters Retrieval from Lidar Waveform Data

    NASA Technical Reports Server (NTRS)

    Ranson, K, Lon; Sun, G.

    2011-01-01

    The effect of forest disturbance on the lidar waveform and the forest biomass estimation was demonstrated by model simulation. The results show that the correlation between stand biomass and the lidar waveform indices changes when the stand spatial structure changes due to disturbances rather than the natural succession. This has to be considered in developing algorithms for regional or global mapping of biomass from lidar waveform data.

  19. Deer Browse Production of Oak Stands in Central Lower Michigan

    Treesearch

    Leslie W. Gysel; Forest Stearns

    1968-01-01

    The extensive oak forests of Lower Michigan provide essential habitat for whitetailed deer and other wildlife. Clearcutting these stands results in high browse production (500-1000 lbs./acre) compared to uncut stands (200-500 lbs./acre). Most browse in uncut stands is under 18 inches tall, whereas much of that in open stands is above snowline and thus available in...

  20. Growth reductions in naturally regenerated southern pine stands in Alabama and Georgia

    Treesearch

    G.A. Ruark; C.E. Thomas; W.A. Bechtold; D.M. May

    1991-01-01

    Data from Forest Inventory and analysis (FIA) units of the USDA Forest Service were used to compare average annual stand-level basal area accretion onto survivor pines in naturally regenerated pine stands throughout Alabama and Georgia. Growth rates measured between 1972-82 were compared to growth rates during the previous 10-year survey cycle in each state. Separate...

  1. Regenerating oak stands the "natural" way

    Treesearch

    Callie Schweitzer; G. Janzen; Daniel C. Dey

    2016-01-01

    In forest stands, there is always a background of growth, senescence, and death of individual trees. There also is always some type of disturbance, from simple and constant events, such as wind, to more intensive and dynamic events, like a timber harvest. Hardwood stands are composed of multiple species, and these species respond differently to disturbance, depending...

  2. 13C-isotopic fingerprint of Pinus pinaster Ait. and Pinus sylvestris L. wood related to the quality of standing tree mass in forests from NW Spain.

    PubMed

    Fernandez, Irene; González-Prieto, Serafin J; Cabaneiro, Ana

    2005-01-01

    Pine forest plantations of Pinus pinaster Ait. and P. sylvestris L. located in Galicia, NW Spain, were selected to study the 13C/12C-isotopic fingerprint in wood core samples in order to find possible relationships between the delta(13)C at natural abundance levels and the quality of the standing tree mass. For each pine species, 24 forests growing on acidic soils were studied: half developed over granite and half over schists. Two dominant trees from each plot, corresponding to all possible combinations of forest stands with high or low site index and with adults or young trees, were drilled at the basal part of trunks using a Pressler drill to obtain tree ring samples. The C-isotopic compositions of the litter and the soil organic matter from different soil depths were also determined and statistically significant correlations between these values and the 13C content of the wood were observed. Despite internal variations due to the influence of site index, tree age and parent material, the isotopic fingerprint of P. pinaster wood (mean value delta13C=-26.2+/-0.8 per thousand) significantly differed (P<0.001) from that of P. sylvestris (mean value delta13C=-24.6+/-0.7 per thousand). Relationships between the quality of the stand and the C-isotopic composition of the wood were observed, high quality stands having trees more 13C-depleted than low quality ones. A high correlation between wood delta13C and site index values for P. pinaster stands (r=-0.667, P<0.001) was found, this correlation being even clearer when only P. pinaster growing over schists (r=-0.833, P<0.001) are considered. Again, the correlation between the site index and the wood delta13C of young P. pinaster trees is higher when plots over granite or schists are separately considered. A similar fact occurs for adult P. sylvestris trees from schists stands, high quality specimens being 13C-depleted compared with low quality ones. On the other hand, 13C natural abundance of wood from P. sylvestris

  3. Secondary forest succession in a tropical dry forest: patterns of development across a 50-year chronosequence in lowland Bolivia

    Treesearch

    Deborah K. Kennard

    2002-01-01

    Stand structure, species richness and population structures of tree species were characterized in 12 stands representing 50 y of succession following slash-and-burn agriculture in a tropical dry forest in lowland Bolivia. Estimates of tree species richness, canopy cover and basal area reached or surpassed 75% of mature forest levels in the 5-, 8-, and 23-y-old stands...

  4. Site preparation burning to improve southern Appalachian pine-hardwood stands: vegetation composition and diversity of 13-year-old stands

    Treesearch

    Barton D. Clinton; J.M. Vose; W.T. Swank

    1993-01-01

    Stand restoration of low-quality, mixed pine-hardwood ecosystems containing a Kalmia Zatifolia L. dominated understory, through cutting, burning, and planting of Pinus strobus L., is common on xeric southern Appalachian forest sites. We examined the effects of this treatment on early vegetation composition and diversity. Four 13-year-old stands were examined. Two of...

  5. Trait Variation Along a Forest Successional Gradient in Dry Tropical Forest, Florida Keys

    NASA Astrophysics Data System (ADS)

    Subedi, S.; Ross, M. S.

    2016-12-01

    In most part of South Florida tropical dry forests, the early colonized trees on disturbed uplands are mostly deciduous species cable of surviving for several years after establishment. However, trees in mature forests are generally characterized by a suite of evergreen species, most of which are completely absent in younger stands even in seedling stage. This complete transition from one functional group to another in the course of stand development suggests a distinct change in the underlying environment during the course of succession. Such change in hammock functional groups as a function of the changing environmental drivers during succession in tropical dry forests is unknown and addressing this question may help to understand which drivers of change act as filters that select for and against particular groups of species and traits. In this study, we evaluate number of important functional traits (specific leaf area, wood density, leaf d13C, leaf N:P ratio, and architectural traits such as height, crown dimensions, diameter at breast height) for woody plant species occurring along a successional gradient across three ecological scales, community, species, and individual. A significant change in the overall trait distribution across the successional gradient is found. Intraspecific trait variation within the community is increased with increase in forest age. Most of these traits have shown correlation with stand age and showed preference to a certain environment. Stand age is the most important variable explaining the distribution of community characteristics. It is found that early successional forest are mostly shaped by environmental driven processes, and as forest get older and structurally more complex, they are increasingly shaped by competitively driven processes leading to limiting similarity. This study has shown that the patterns of trait shift can be predictable and can be used to characterize habitats and stage of forest succession in dry tropical

  6. Using silviculture to sustain upland oak forests under stress on the Daniel Boone National Forest, Kentucky

    Treesearch

    Callie Jo Schweitzer; Kurt W. Gottschalk; Jeff W. Stringer; Stacy L. Clark; David L. Loftis

    2011-01-01

    We used a large-scale silvicultural assessment designed to examine the efficacy of five stand-level prescriptions in reducing the potential impacts of gypsy moth infestations and oak decline on upland hardwood forests in Kentucky's Daniel Boone National Forest. Prescriptions involved a mix of intermediate stand treatments aimed at increasing residual tree vigor...

  7. Biogeographical patterns of biomass allocation in leaves, stems, and roots in China's forests.

    PubMed

    Zhang, Hao; Wang, Kelin; Xu, Xianli; Song, Tongqing; Xu, Yanfang; Zeng, Fuping

    2015-11-03

    To test whether there are general patterns in biomass partitioning in relation to environmental variation when stand biomass is considered, we investigated biomass allocation in leaves, stems, and roots in China's forests using both the national forest inventory data (2004-2008) and our field measurements (2011-2012). Distribution patterns of leaf, stem, and root biomass showed significantly different trends according to latitude, longitude, and altitude, and were positively and significantly correlated with stand age and mean annual precipitation. Trade-offs among leaves, stems, and roots varied with forest type and origin and were mainly explained by stand biomass. Based on the constraints of stand biomass, biomass allocation was also influenced by forest type, origin, stand age, stand density, mean annual temperature, precipitation, and maximum temperature in the growing season. Therefore, after stand biomass was accounted for, the residual variation in biomass allocation could be partially explained by stand characteristics and environmental factors, which may aid in quantifying carbon cycling in forest ecosystems and assessing the impacts of climate change on forest carbon dynamics in China.

  8. Forest production dynamics along a wood density spectrum in eastern US forests

    Treesearch

    C.W. Woodall; M.B. Russell; B.F. Walters; A.W. D' Amato; K. Zhu; S.S. Saatchi

    2015-01-01

    Emerging plant economics spectrum theories were confirmed across temperate forest systems of the eastern US where the use of a forest stand's mean wood density elucidated forest volume and biomass production dynamics integrating aspects of climate, tree mortality/growth, and rates of site occupancy.

  9. Impact of Stand Management Practices on Beetle Diversity

    Treesearch

    Stephen P. Cook

    2004-01-01

    Abstract - Insects are useful indicators of change within ecosystems because of their abundance, richness and functional importance. Stand management practices impact the insect community within a forest. Therefore, the objective of the project is to determine the impact of various stand management practices on the diversity of beetles within...

  10. Birch Stands Growth Increase in Western Siberia

    NASA Technical Reports Server (NTRS)

    Kharuk, Viacheslav I.; Kuzmichev, Valeriy V.; Im, Sergey T.; Ranson, Kenneth J.

    2014-01-01

    Birch (Betula pendula Roth) growth within the Western Siberia forest-steppe was analyzed based on long-term (1897-2006) inventory data (height, diameter at breast height [dbh], and stand volume). Analysis of biometry parameters showed increased growth at the beginning of twenty-first century compared to similar stands (stands age = 40-60 years) at the end of nineteenth century. Mean height, dbh, and stem volume increased from 14 to 20 m, from 16 to 22 cm, and from approx. 63 to approx. 220 cu m/ha, respectively. Significant correlations were found between the stands mean height, dbh, and volume on the one hand, and vegetation period length (r(sub s) = 0.71 to 0.74), atmospheric CO2 concentration (r(sub s) = 0.71 to 0.76), and drought index (Standardized Precipitation-Evapotranspiration Index, r(sub s) = -0.33 to -0.51) on the other hand. The results obtained have revealed apparent climate-induced impacts (e.g. increase of vegetation period length and birch habitat drying due to drought increase) on the stands growth. Along with this, a high correlation of birch biometric parameters and [CO2] in ambient air indicated an effect of CO2 fertilization. Meanwhile, further drought increase may switch birch stand growth into decline and greater mortality as has already been observed within the Trans-Baikal forest-steppe ecotone.

  11. Terrestrial and stream amphibians across clearcut-forest interfaces in the Siskiyou Mountains, Oregon

    USGS Publications Warehouse

    Biek, Roman; Mills, L. Scott; Bury, R. Bruce

    2002-01-01

    Timber harvest in the Pacific Northwest has resulted in a highly fragmented landscape. but there is no information on responses of amphibians to forest edges for this region. We investigated abundance of terrestrial and stream-dwelling amphibians on the interface of recent clearcuts and mature forest in the Siskiyou Mountains, Oregon, in summer and fall of 1998. We assessed relative abundance of terrestrial -amphibians on four clearcut forest transects with a combination of pitfall trapping and manual searches. Ensantinas and Del Norte salamanders, the most frequently recorded species, were found on all four sites.  While we commonly captured ensantinas using both techniques, we caught most Del Norte salamanders during manual searches. For both species we found no differences in abundance associated with distance to forest edge. Lack of differences in salamander abundance among clearcut and adjacent forests may be related lo large amounts of small woody debris that remained in the clearcuts. The abundance of larvae of tailed frogs and Pacific giant salamanders in five headwater streams was markedly lower in clearcuts than in downstream mature forest stands. No obvious differences existed for stream habitat variables across transects. but abundance of metamorphosed individuals and recruitment may be reduced in clearcut areas due lo hotter and drier conditions during

  12. North Dakota's Forests 2010

    Treesearch

    David E. Haugen; Robert Harsel; Aaron Bergdahl; Tom Claeys; Christopher W. Woodall; Barry T. Wilson; Susan J. Crocker; Brett J. Butler; Cassandra M. Kurtz; Mark A. Hatfield; Charles H. Barnett; Grant Domke; Dan Kaisershot; W. Keith Moser; Andrew J. Lister; Dale D. Gormanson

    2013-01-01

    The second annual inventory of North Dakota's forests reports more than 772,000 acres of forest land with an average volume of more than 921 cubic feet per acre. Forest land is dominated by the bur oak forest type, which occupies more than a third of the total forest land area. The poletimber stand-size class represents 39 percent of forest land, followed by...

  13. Review of forest landscape models: types, methods, development and applications

    Treesearch

    Weimin Xi; Robert N. Coulson; Andrew G. Birt; Zong-Bo Shang; John D. Waldron; Charles W. Lafon; David M. Cairns; Maria D. Tchakerian; Kier D. Klepzig

    2009-01-01

    Forest landscape models simulate forest change through time using spatially referenced data across a broad spatial scale (i.e. landscape scale) generally larger than a single forest stand. Spatial interactions between forest stands are a key component of such models. These models can incorporate other spatio-temporal processes such as...

  14. Rate of value change in New England timber stands

    Treesearch

    Stanford L. Arner; David A. Gansner; Thomas W. Birch; Thomas W. Birch

    1990-01-01

    Analyses of remeasured plot data show that between the last two forest inventories of New England, compound rates of value change in timber stands averaged 4.2 percent and ranged from -26 to + 43 percent. Three key characteristics of stand condition (species composition, tree size, and stocking) can be used to estimate economic growth. For example, stands with (1) more...

  15. Cultural practices in Appalachian hardwood sapling stands--are they worthwhile?

    Treesearch

    Gary W. Miller

    1986-01-01

    Forest managers often question the economic feasibility of cultural practices in hardwood sapling stands. Investment factors, including initial treatment cost, required rate of return, investment period, and stand response to treatment are discussed in terms of how they affect the outcome of early investments in even-aged hardwood stands. Attention is focused on...

  16. Growth patterns of Tsuga canadensis in managed uneven-aged northern conifer stands

    Treesearch

    Laura S. Kenefic; Robert S. Seymour

    2000-01-01

    This study reports patterns of regeneration and growth for 100 eastern hemlock (Tsuga canadensis (L.) Carr.) up to 20 inches (50 cm) dbh in two mixed-species selection stands on the Penobscot Experimental Forest in east-central Maine. The study stands are part of a U.S.D.A. Forest Service experiment in which eastern hemlock has remained stable over a...

  17. Cordwood Yields From Thinnings in Young Oak Stands in the Missouri Ozarks

    Treesearch

    Kenneth W. Seidel

    1966-01-01

    Proposed construction in Missouri of pulpmills using oak cordwood should result in a greater demand for pole-size oak trees, thus making needed thinnings feasible in young oak stands. According to the 1958 forest survey, poletimber stands (which are mainly oak) occupy 39 percent of the commercial forest area of the eastern Ozakrs, more than any other size class. More...

  18. Interannual Variation in Stand Transpiration is Dependent Upon Tree Species

    NASA Astrophysics Data System (ADS)

    Ewers, B. E.; Mackay, D. S.; Burrows, S. N.; Ahl, D. E.; Samanta, S.

    2003-12-01

    In order to successfully predict transpirational water fluxes from forested watersheds, interannual variability in transpiration must be quantified and understood. In a heterogeneous forested landscape in northern Wisconsin, we quantified stand transpiration across four forest cover types representing more than 80 percent of the land area in order to 1) quantify differences in stand transpiration and leaf area over two years and 2) determine the mechanisms governing the changes in transpiration over two years. We measured sap flux in eight trees of each tree species in the four cover types. We found that in northern hardwoods, the leaf area of sugar maple increased between the two measurement years with transpiration per unit ground area increasing even more than could be explained by leaf area. In an aspen stand, tent caterpillars completely defoliated the stand for approximately a month until a new set of leaves flushed out. The new set of leaves resulted in a lower leaf area but the same transpiration per unit leaf area indicating there was no physiological compensation for the lower leaf area. At the same time, balsam fir growing underneath the aspen increased their transpiration rate in response to greater light penetration through the dominant aspen canopy Red pine had a thirty percent change in leaf area within a growing season due to multiple cohorts of leaves and transpiration followed this leaf area dynamic. In a forested wetland, white cedar transpiration was proportional to surface water depth between the two years. Despite the specific tree species' effects on stand transpiration, all species displayed a minimum water potential regulation resulting in a saturating response of transpiration to vapor pressure deficit that did not vary across the two years. This physiological set point will allow future water flux models to explain mechanistically interannual variability in transpiration of this and similar forests.

  19. Carbon balance of a partially-harvested mixed conifer forest following mountain pine beetle attack and its comparison to a clearcut

    NASA Astrophysics Data System (ADS)

    Mathys, A.; Black, T. A.; Nesic, Z.; Nishio, G.; Brown, M.; Spittlehouse, D. L.; Fredeen, A. L.; Bowler, R.; Jassal, R. S.; Grant, N. J.; Burton, P. J.; Trofymow, J. A.

    2013-03-01

    The recent mountain pine beetle (MPB) outbreak has had an impact on the carbon (C) cycling of lodgepole pine forests in British Columbia. This study examines how partial harvesting as a forest management response to MPB infestation affects the net ecosystem production (NEP) of a mixed conifer forest (MPB-09) in Interior BC. MPB-09 is a 70-yr old stand that was partially harvested in 2009 after it had been attacked by MPB. Using the eddy-covariance technique, the C dynamics of the stand were studied over two years and compared to an adjacent clearcut (MPB-09C) over the growing season. The annual NEP at MPB-09 increased from -108 g C m-2 in 2010 to -57 g C m-2 in 2011. The increase of NEP was due to the associated increase in annual gross ecosystem photosynthesis (GEP) from 812 g C m-2 in 2010 to 954 g C m-2 in 2011 exceeding the increase in annual respiration (Re) from 920 g C m-2 to 1011 g C m-2 during the two years. During the growing season of 2010, NEP at MPB-09C was -132 g C m-2 indicating high C losses in the clearcut. MPB-09 was a C sink during the growing season of both years, increasing from 9 g C m-2 in 2010 to 47 g C m-2 in 2011. The increase of NEP in the partially-harvested stand amounted to a recovery corresponding to a 25% increase in the maximum assimilation rate in the second year. This study shows that retaining the healthy residual forest can result in higher C sequestration of MPB-attacked stands compared to clearcut harvesting.

  20. Predictive Mapping of Forest Attributes on the Fishlake National Forest

    Treesearch

    Tracey S. Frescino; Gretchen G. Moisen

    2005-01-01

    Forest land managers increasingly need maps of forest characteristics to aid in planning and management. A set of 30-m resolution maps was prepared for the Fishlake National Forest by modeling FIA plot variables as nonparametric functions of ancillary digital data. The set includes maps of volume, biomass, growth, stand age, size, crown cover, and various aspen...

  1. Estimating Value Contribution of Tree and Stand Condition

    Treesearch

    R. Joss Hanna; Richard P. Thompson; Douglas D. Piirto; Jay E. Noel

    1997-01-01

    Key issues in encouraging forest management at the interface level in the oak woodlands are fire abatement, stand improvement, infection reduction, and hazard tree removal. The development of effective management prescriptions for stand improvement and economic returns provide guidance for homeowners, appraisers, and realtors. The purpose of this research project was...

  2. A Silvicultural Evaluation of Four Methods of Marking Second-growth Northern Hardwood Stands

    Treesearch

    Rodney D. Jacobs

    1966-01-01

    Second-growth northern hardwood stands occupy an important segment of the commercial forest land of Upper Michigan and northern Wisconsin. The size- and age-class distributions and species composition of these stands vary considerably, but under all conditions most of the trees are highly defective or poorly formed or of an undesirable species. Forest managers...

  3. North Carolina's forests, 2002

    Treesearch

    Mark J. Brown; Barry D. New; Sonja N. Oswalt; Tony G. Johnson; Victor A. Rudis

    2006-01-01

    In 2002, forests covered 18.3 million acres in North Carolina, of which 17.7 million were classified as timberland. Hardwood forest types prevailed on 72 percent of timberland and planted pine stands occupied 15 percent. Nonindustrial private forest landowners controlled 78 percent of timberland, forest industry holdings declined to 8 percent, and publicly owned...

  4. Reducing uncertainty and increasing consistency: technical improvements to forest carbon pool estimation using the national forest inventory of the US

    Treesearch

    C.W. Woodall; G.M. Domke; J. Coulston; M.B. Russell; J.A. Smith; C.H. Perry; S.M. Ogle; S. Healey; A. Gray

    2015-01-01

    The FIA program does not directly measure forest C stocks. Instead, a combination of empirically derived C estimates (e.g., standing live and dead trees) and models (e.g., understory C stocks related to stand age and forest type) are used to estimate forest C stocks. A series of recent refinements in FIA estimation procedures have sought to reduce the uncertainty...

  5. Comparison of the carbon stock in forest soil of sessile oak and beech forests

    NASA Astrophysics Data System (ADS)

    Horváth, Adrienn; Bene, Zsolt; Bidló, András

    2016-04-01

    Forest ecosystems are the most important carbon sinks. The forest soils play an important role in the global carbon cycle, because the global climate change or the increase of atmospheric CO2 level. We do not have enough data about the carbon stock of soils and its change due to human activities, which have similar value to carbon content of biomass. In our investigation we measured the carbon stock of soil in 10 stands of Quercus petraea and Fagus sylvatica. We took a 1.1 m soil column with soil borer and divided to 11 samples each column. The course organic and root residues were moved. After evaluation, we compared our results with other studies and the carbon stock of forests to each other. Naturally, the amount of SOC was the highest in the topsoil layers. However, we found significant difference between forest stands which stayed on the same homogenous bedrock, but very close to each other (e.g. distance was 1 or 2 km). We detected that different forest utilizations and tree species have an effect on the forest carbon as the litter as well (amount, composition). In summary, we found larger amount (99.1 C t/ha on average) of SOC in soil of stands, where sessile oak were the main stand-forming tree species. The amount of carbon was the least in turkey oak-sessile oak stands (85.4 C t/ha on average). We found the highest SOC (118.3 C t/ha) in the most mixed stand (silver lime-beech-red oak). In the future, it will be very important: How does climate change affect the spread of tree species or on carbon storage? Beech is more sensitive, but even sessile oak. These species are expected to replace with turkey oak, which is less sensitive to drought. Thus, it is possible in the future that we can expect to decrease of forest soil carbon stock capacity, which was confirmed by our experiment. Keywords: carbon sequestration, mitigation, Fagus sylvatica, Quercus petraea, litter Acknowledgements: Research is supported by the "Agroclimate.2" (VKSZ_12-1-2013-0034) EU

  6. Natural decay resistance of heartwood from dead, standing yellow-cedar trees : laboratory evaluations

    Treesearch

    Rodney C. De Groot; Bessie Woodward; Paul E. Hennon

    2000-01-01

    Yellow-cedar trees have been mysteriously dying for more than a century in southeast Alaska. As these stems continue to stand for decades in the forest, foliage, twigs, and branches deteriorate. The sapwood in the stem degrades, leaving columns of essentially heartwood standing like ghosts in the forest until they eventually drop. To estimate the potential for...

  7. Biogeographical patterns of biomass allocation in leaves, stems, and roots in China’s forests

    PubMed Central

    Zhang, Hao; Wang, Kelin; Xu, Xianli; Song, Tongqing; Xu, Yanfang; Zeng, Fuping

    2015-01-01

    To test whether there are general patterns in biomass partitioning in relation to environmental variation when stand biomass is considered, we investigated biomass allocation in leaves, stems, and roots in China’s forests using both the national forest inventory data (2004–2008) and our field measurements (2011–2012). Distribution patterns of leaf, stem, and root biomass showed significantly different trends according to latitude, longitude, and altitude, and were positively and significantly correlated with stand age and mean annual precipitation. Trade-offs among leaves, stems, and roots varied with forest type and origin and were mainly explained by stand biomass. Based on the constraints of stand biomass, biomass allocation was also influenced by forest type, origin, stand age, stand density, mean annual temperature, precipitation, and maximum temperature in the growing season. Therefore, after stand biomass was accounted for, the residual variation in biomass allocation could be partially explained by stand characteristics and environmental factors, which may aid in quantifying carbon cycling in forest ecosystems and assessing the impacts of climate change on forest carbon dynamics in China. PMID:26525117

  8. Managing Appalachian hardwood stands using four regeneration practices--34 year results

    Treesearch

    H. Clay Smith; Gary W. Miller

    1987-01-01

    Adjacent Appalachian hardwood stands in West Virginia established on excellent growing sites were managed for a 34-year period using four regeneration practices. These practices included a commercial clearcut, 15.5-in diameter-limit, and two single-tree selection practices. An uncut area was maintained as a control. Stand development, growth response, and some stumpage...

  9. Mature and old-growth riparian forests: structure, dynamics, and effects on Adirondack stream habitats.

    PubMed

    Keeton, William S; Kraft, Clifford E; Warren, Dana R

    2007-04-01

    Riparian forests regulate linkages between terrestrial and aquatic ecosystems, yet relationships among riparian forest development, stand structure, and stream habitats are poorly understood in many temperate deciduous forest systems. Our research has (1) described structural attributes associated with old-growth riparian forests and (2) assessed linkages between these characteristics and in-stream habitat structure. The 19 study sites were located along predominantly first- and second-order streams in northern hardwood-conifer forests in the Adirondack Mountains of New York (U.S.A.). Sites were classified as mature forest (6 sites), mature with remnant old-growth trees (3 sites), and old-growth (10 sites). Forest-structure attributes were measured over stream channels and at varying distances from each bank. In-stream habitat features such as large woody debris (LWD), pools, and boulders were measured in each stream reach. Forest structure was examined in relation to stand age using multivariate techniques, ANOVA, and linear regression. We investigated linkages between forest structure and stream characteristics using similar methods, preceded by information-theoretic modeling (AIC). Old-growth riparian forest structure is more complex than that found in mature forests and exhibits significantly greater accumulations of aboveground tree biomass, both living and dead. In-stream LWD volumes were significantly (alpha = 0.05) greater at old-growth sites (200 m3/ha) compared to mature sites (34 m3/ha) and were strongly related to the basal area of adjacent forests. In-stream large-log densities correlated strongly with debris-dam densities. AIC models that included large-log density, debris-dam density, boulder density, and bankfull width had the most support for predicting pool density. There were higher proportions of LWD-formed pools relative to boulder-formed pools at old-growth sites as compared to mature sites. Old-growth riparian forests provide in

  10. Impacts of fire on forest age and runoff in mountain ash forests

    USGS Publications Warehouse

    Wood, S.A.; Beringer, J.; Hutley, L.B.; McGuire, A.D.; Van Dijk, A.; Kilinc, M.

    2008-01-01

    Runoff from mountain ash (Eucalyptus regnans F.Muell.) forested catchments has been shown to decline significantly in the few decades following fire - returning to pre-fire levels in the following centuries - owing to changes in ecosystem water use with stand age in a relationship known as Kuczera's model. We examined this relationship between catchment runoff and stand age by measuring whole-ecosystem exchanges of water using an eddy covariance system measuring forest evapotranspiration (ET) combined with sap-flow measurements of tree water use, with measurements made across a chronosequence of three sites (24, 80 and 296 years since fire). At the 296-year old site eddy covariance systems were installed above the E. regnans overstorey and above the distinct rainforest understorey. Contrary to predictions from the Kuczera curve, we found that measurements of whole-forest ET decreased by far less across stand age between 24 and 296 years. Although the overstorey tree water use declined by 1.8 mm day-1 with increasing forest age (an annual decrease of 657 mm) the understorey ET contributed between 1.2 and 1.5 mm day-1, 45% of the total ET (3 mm day-1) at the old growth forest. ?? CSIRO 2008.

  11. Carbon balance of a partially harvested mixed conifer forest following mountain pine beetle attack and its comparison to a clear-cut

    NASA Astrophysics Data System (ADS)

    Mathys, A.; Black, T. A.; Nesic, Z.; Nishio, G.; Brown, M.; Spittlehouse, D. L.; Fredeen, A. L.; Bowler, R.; Jassal, R. S.; Grant, N. J.; Burton, P. J.; Trofymow, J. A.; Meyer, G.

    2013-08-01

    The recent mountain pine beetle (MPB) outbreak has had an impact on the carbon (C) cycling of lodgepole pine forests in British Columbia. This study examines how partial harvesting as a forest management response to MPB infestation affects the net ecosystem production (NEP) of a mixed conifer forest (MPB-09) in Interior BC. MPB-09 is a 70-year-old stand that was partially harvested in 2009 after it had been attacked by MPB. Using the eddy-covariance technique, the C dynamics of the stand were studied over two years and compared to an adjacent clear-cut (MPB-09C) over the summertime. The annual NEP at MPB-09 increased from -108 g C m-2 in 2010 to -57 g C m-2 in 2011. The increase of NEP was due to the associated increase in annual gross ecosystem photosynthesis (GEP) from 812 g C m-2 in 2010 to 954 g C m-2 in 2011, exceeding the increase in annual respiration (Re) from 920 g C m-2 to 1011 g C m-2 during the two years. During the four month period between June and September 2010, NEP at MPB-09C was -103 g C m-2, indicating high C losses in the clear-cut. MPB-09 was a C sink during the growing season of both years, increasing from 9 g C m-2 in 2010 to 47 g C m-2 in 2011. The increase of NEP in the partially harvested stand amounted to a recovery corresponding to a 26% increase in the maximum assimilation rate in the second year. This study shows that retaining the healthy residual forest can result in higher C sequestration of MPB-attacked stands compared to clear-cut harvesting.

  12. Fire and stand history in two limber pine (Pinus flexilis) and Rocky Mountain bristlecone pine (Pinus aristata) stands in Colorado

    Treesearch

    Peter M. Brown; Anna W. Schoettle

    2008-01-01

    We developed fire-scar and tree-recruitment chronologies from two stands dominated by limber pine and Rocky Mountain bristlecone pine in central and northern Colorado. Population structures in both sites exhibit reverse-J patterns common in uneven-aged forests. Bristlecone pine trees were older than any other at the site or in the limber pine stand, with the oldest...

  13. Old growth in northwestern California national forests.

    Treesearch

    Debby Beardsley; Ralph. Warbington

    1996-01-01

    This report estimates old-growth forest area and summarizes stand characteristics of old growth in northwestern California National Forests by forest type. Old-growth definitions for each forest type are used.

  14. Vegetative composition in forested areas following application of desired forest condition treatments

    Treesearch

    Trent A. Danley; Andrew W. Ezell; Emily B. Schultz; John D. Hodges

    2015-01-01

    Desired forest conditions, or DFCs, are recently created parameters which strive to create diverse stands of hardwoods of various species and age classes, along with varying densities and canopy gaps, through the use of uneven-aged silvicultural methods and repeated stand entries. Little research has been conducted to examine residual stand composition and hardwood...

  15. Coarse woody type: A new method for analyzing coarse woody debris and forest change

    Treesearch

    C. W. Woodall; L. M. Nagel

    2006-01-01

    The species composition of both standing live and down dead trees has been used separately to determine forest stand dynamics in large-scale forest ecosystem assessments. The species composition of standing live trees has been used to indicate forest stand diversity while the species composition of down dead trees has been used to indicate wildlife habitat. To assess...

  16. Forest discrimination with multipolarization imaging radar

    NASA Technical Reports Server (NTRS)

    Ford, J. P.; Wickland, D. E.

    1985-01-01

    The use of radar polarization diversity for discriminating forest canopy variables on airborne synthetic-aperture radar (SAR) images is evaluated. SAR images were acquired at L-Band (24.6 cm) simultaneously in four linear polarization states (HH, HV, VH, and VV) in South Carolina on March 1, 1984. In order to relate the polarization signatures to biophysical properties, false-color composite images were compared to maps of forest stands in the timber compartment. In decreasing order, the most useful correlative forest data are stand basal area, forest age, site condition index, and forest management type. It is found that multipolarization images discriminate variation in tree density and difference in the amount of understory, but do not discriminate between evergreen and deciduous forest types.

  17. Arkansas’ forests, 2005

    Treesearch

    James F. Rosson; Anita K. Rose

    2010-01-01

    The principal fi ndings of the eighth forest survey of Arkansas are presented. This survey marks a major change in the FIA sampling protocol from a periodic prism sample to an annualized fi xed-plot sample. Topics examined include forest area, ownership, forest-type groups, stand structure, basal area, timber volume, growth, removals, and mortality, crown...

  18. The role of soil drainage class in carbon dioxide exchange and decomposition in boreal black spruce (Picea mariana) forest stands

    USGS Publications Warehouse

    Wickland, K.P.; Neff, J.C.; Harden, J.W.

    2010-01-01

    Black spruce (Picea mariana (Mill.) B.S.P.) forest stands range from well drained to poorly drained, typically contain large amounts of soil organic carbon (SOC), and are often underlain by permafrost. To better understand the role of soil drainage class in carbon dioxide (CO2) exchange and decomposition, we measured soil respiration and net CO2 fluxes, litter decomposition and litterfall rates, and SOC stocks above permafrost in three Alaska black spruce forest stands characterized as well drained (WD), moderately drained (MD), and poorly drained (PD). Soil respiration and net CO2 fluxes were not significantly different among sites, although the relation between soil respiration rate and temperature varied with site (Qw: WD > MD > PD). Annual estimated soil respiration, litter decomposition, and groundcover photosynthesis were greatest at PD. These results suggest that soil temperature and moisture conditions in shallow organic horizon soils at PD were more favorable for decomposition compared with the better drained sites. SOC stocks, however, increase from WD to MD to PD such that surface decomposition and C storage are diametric. Greater groundcover vegetation productivity, protection of deep SOC by permafrost and anoxic conditions, and differences in fire return interval and (or) severity at PD counteract the relatively high near-surface decomposition rates, resulting in high net C accumulation.

  19. Adaptive forest management for drinking water protection under climate change

    NASA Astrophysics Data System (ADS)

    Koeck, R.; Hochbichler, E.

    2012-04-01

    Drinking water resources drawn from forested catchment areas are prominent for providing water supply on our planet. Despite the fact that source waters stemming from forested watersheds have generally lower water quality problems than those stemming from agriculturally used watersheds, it has to be guaranteed that the forest stands meet high standards regarding their water protection functionality. For fulfilling these, forest management concepts have to be applied, which are adaptive regarding the specific forest site conditions and also regarding climate change scenarios. In the past century forest management in the alpine area of Austria was mainly based on the cultivation of Norway spruce, by the way neglecting specific forest site conditions, what caused in many cases highly vulnerable mono-species forest stands. The GIS based forest hydrotope model (FoHyM) provides a framework for forest management, which defines the most crucial parameters in a spatial explicit form. FoHyM stratifies the spacious drinking water protection catchments into forest hydrotopes, being operational units for forest management. The primary information layer of FoHyM is the potential natural forest community, which reflects the specific forest site conditions regarding geology, soil types, elevation above sea level, exposition and inclination adequately and hence defines the specific forest hydrotopes. For each forest hydrotope, the adequate tree species composition and forest stand structure for drinking water protection functionality was deduced, based on the plant-sociological information base provided by FoHyM. The most important overall purpose for the related elaboration of adaptive forest management concepts and measures was the improvement of forest stand stability, which can be seen as the crucial parameter for drinking water protection. Only stable forest stands can protect the fragile soil and humus layers and hence prevent erosion process which could endanger the water

  20. Forest conditions in the San Francisco Mountains Forest Reserve, Arizona

    Treesearch

    John B. Leiberg; Theodore F. Rixon; Arthur. Dodwell

    1904-01-01

    On April 12, 1902, President Roosevelt issued a proclamation "for the purpose of consolidating into one reserve the lands heretofore embraced in the San Francisco Mountains Forest Reserves and of including therein the other adjacent lands within the description herein after given." The consolidated area is now known as the San Francisco Mountains Forest...

  1. Composition and development of reproduction in two-age Appalachian hardwood stands: 20-year results

    Treesearch

    Gary W. Miller; James N. Kochenderfer; Desta Fekedulegn

    2004-01-01

    In the early 1980s, silviculturists with the Northeastern Research Station and Monongahela National Forest envisioned that managing some Appalachian hardwood stands to promote two-age structures would be part of an effective strategy for managing multi-use forests. Two-age stands provided the light and seedbed conditions necessary for regenerating numerous desirable...

  2. Douglas-fir ectomycorrhizae in 40- and 400-year-old stands: mycobiont availability to late successional western hemlock.

    Treesearch

    T. R. Horton; R. Molina; K. Hood

    2005-01-01

    We investigated ectomycorrhizal (EM) fungi in forest stands containing both early successional Douglas-fir and late successional western hemlock at two points in the typical stand development by identifying EM fungi from roots of Douglas-fir and western hemlock in mixed stands. Tn an early seral stage forest, EM roots of western hemlock seedlings and intermingling 40-...

  3. Late-successional forests and northern spotted owls: how effective is the Northwest Forest Plan?

    Treesearch

    Miles Hemstrom; Martin G. Raphael

    2000-01-01

    This paper describes the late-successional and old-growth forest and the northern spotted owl effectiveness monitoring plans for the Northwest Forest Plan. The effectiveness monitoring plan for late-successional and old-growth forests will track changes in forest spatial distribution, and within-stand structure and composition, and it will predict future trends.

  4. Wildlife of southern forests habitat & management (Chapter 4): Defining the Forests

    Treesearch

    James G. Dickson; Raymond M. Sheffield

    2003-01-01

    Forests of the South are very diverse and productive. Included among southern forests are the boreal spruce- fir forests of the highest mountain peaks of the Blue Ridge Mountains to the lowest bottomland hardwoods on flood-deposited soil with elevations near sea level. In between are the diverse upland hardwood stands in northerly mountainous areas of the South and...

  5. Forest health status in Russia

    Treesearch

    Vladislav A. Alexeyev

    1998-01-01

    About 886.5 Mha in Russia is occupied by forests, including 763.5 Mha of tree stands and 123 Mha of nonstocked lands. The Russian forests comprise about 22 percent of the earth's forest area or 43 percent of the earth's temperate and boreal forests. Main forest-forming species are Larix sp. (32 percent of the growing stock), Pinus...

  6. Forest vegetation simulation tools and forest health assessment

    Treesearch

    Richard M. Teck; Melody Steele

    1995-01-01

    A Stand Hazard Rating System for Central ldaho forests has been incorporated into the Central ldaho Prognosis variant of the Forest Vegetation Simulator to evaluate how insects, disease and fire hazards within the Deadwood River Drainage change over time. A custom interface, BOISE.COMPUTE.PR, has been developed so hazard ratings can be electronically downloaded...

  7. Use of Aerial Hyperspectral Imaging For Monitoring Forest Health

    Treesearch

    Milton O. Smith; Nolan J. Hess; Stephen Gulick; Lori G. Eckhardt; Roger D. Menard

    2004-01-01

    This project evaluates the effectiveness of aerial hyperspectral digital imagery in the assessment of forest health of loblolly stands in central Alabama. The imagery covers 50 square miles, in Bibb and Hale Counties, south of Tuscaloosa, AL, which includes intensive managed forest industry sites and National Forest lands with multiple use objectives. Loblolly stands...

  8. Regeneration in defoliated and thinned hardwood stands of north-central West Virginia

    Treesearch

    R. M. Muzika; M. J. Twery

    1995-01-01

    Overstory species regeneration was examined in 1989, prior to gypsy moth defoliation and thinnings, on 16 stands in the West Virginia University Forest. Three stands were thinned and defoliated while five were thinned only and three were defoliated only. Five stands were neither thinned nor defoliated. Data were collected from these stands for three years subsequent to...

  9. Tentative guides for the selection of plus trees and superior stands in Douglas-fir.

    Treesearch

    Leo A. Isaac

    1955-01-01

    Interest among foresters in forest tree improvement has increased rapidly in recent years. Geneticists have learned that some individual trees greatly excel their neighbors in desirable characteristics, and that some entire stands are superior to other stands of the same species in a general locality. They have learned that many of the desirable tree characteristics...

  10. Satellite-based prediction of rainfall interception by tropical forest stands of a human-dominated landscape in Central Sulawesi, Indonesia

    NASA Astrophysics Data System (ADS)

    Nieschulze, Jens; Erasmi, Stefan; Dietz, Johannes; Hölscher, Dirk

    2009-01-01

    SummaryRainforest conversion to other land use types drastically alters the hydrological cycle in which changes in rainfall interception contribute significantly to the observed differences. However, little is known about the effects of more gradual changes in forest structure and at regional scales. We studied land use types ranging from natural forest over selectively-logged forest to cacao agroforest in a lower montane region in Central Sulawesi, Indonesia, and tested the suitability of high-resolution optical satellite imagery for modeling observed interception patterns. Investigated characteristics indicating canopy structure were mean and standard deviation of reflectance values, local maxima, and self-similarity measures based on the grey level co-occurrence matrix and geostatistical variogram analysis. Previously studied and published rainfall interception data comprised twelve plots and median values per land use type ranged from 30% in natural forest to 18% in cacao agroforests. A linear regression model with local maxima, mean contrast and normalized digital vegetation index (NDVI) as regressors was able to explain more than 84% ( Radj2) of the variation encountered in the data. Other investigated characteristics did not prove significant in the regression analysis. The model yielded stable results with respect to cross-validation and also produced realistic values and spatial patterns when applied at the landscape level (783.6 ha). High values of interception were rare and localized in natural forest stands distant to villages, whereas low interception characterized the intensively used sites close to settlements. We conclude that forest use intensity significantly reduced rainfall interception and satellite image analysis can successfully be applied for its regional prediction, and most forest in the study region has already been subject to human-induced structural changes.

  11. From defective hardwood stand to multiple use opportunity

    Treesearch

    Charles E. McGee

    1972-01-01

    A 40-year old clearcutting, originally made as an example of destructive logging, now supports one of the best mixed hardwood stands on the Bent Creek Experimental Forest. Such desirable intolerants as yellow-poplar provide potential for timber; some high- and low-quality oaks provide timber and wildlife values; and the entire young stand has a pleasing appearance....

  12. Harvesting systems for western stand health improvement cuttings

    Treesearch

    Bruce R. Hartsough; Bryce J. Stokes; Joseph F. McNeel; William F. Watson

    1995-01-01

    A significant percentage of the forested area in the western United States is comprised of stands that have been altered over time by human activities, especially fire suppression, and are now being damaged by droughts, insect attacks, and wildfires. These stands should be returned to a condition where "biotic and abiotic influences do not threaten resource...

  13. User's guide for Northeast Stand Exam Program (NEST Version 2.1).

    Treesearch

    Thomas M. Schuler; Brian T. Simpson

    1991-01-01

    Explains the Northeast Stand Exam (NEST Version 2.1) program. The NEST program was designed for use on the Polycorder 600 Series electronic portable data recorder to record data collected from the standard permanent plot as described by the Stand Culture and Stand Establishment Working Groups of the Northeastern Forest Experiment Station.

  14. Alabama’s forests, 2010

    Treesearch

    Andrew J. Hartsell; Jason A. Cooper

    2013-01-01

    The principle findings of the ninth forest survey of Alabama (2010) and changes that have occurred since the previous surveys are presented. Topics examined include forest area, ownership, forest-type groups, stand structure, basal area, timber volume, growth removals, and mortality. Alabama’s contribution to the Nation’s forest resources and regional comparisons are...

  15. Deriving fair incentives for management of hardwood timber stands

    Treesearch

    David A. Gansner; W. Herrick Owen; David N. Larsen; David N. Larsen

    1973-01-01

    The authors present a practical method for deriving timber-management incentive payments and demonstrate its application in forest stands of upland hardwoods. The suggested incentive payment is based on the differences between discounted costs and returns of deliberate forest management and the "harvest and let grow" option.

  16. Promoting soft mast for wildlife in intensively managed forests

    Treesearch

    John J. Stransky; John H. Roese

    1984-01-01

    The fruit of woody plants is important as food for wildlife (Martin et al. 1951, Lay 1965). The relation of fruit production to southern forest stand conditions has been explored in only a few studies. Fruit production is greater in forest clearings than in closed forest stands (Lay 1966, Elalls and Alcaniz 1968). In Georgia slash pine (Pinus elliottii...

  17. Soil microbiological properties and enzymatic activities of long-term post-fire recovery in dry and semiarid Aleppo pine (Pinus halepensis M.) forest stands

    NASA Astrophysics Data System (ADS)

    Hedo, J.; Lucas-Borja, M. E.; Wic, C.; Andrés-Abellán, M.; de Las Heras, J.

    2015-02-01

    Wildfires affecting forest ecosystems and post-fire silvicultural treatments may cause considerable changes in soil properties. The capacity of different microbial groups to recolonise soil after disturbances is crucial for proper soil functioning. The aim of this work was to investigate some microbial soil properties and enzyme activities in semiarid and dry Aleppo pine (Pinus halepensis M.) forest stands. Different plots affected by a wildfire event 17 years ago without or with post-fire silvicultural treatments 5 years after the fire event were selected. A mature Aleppo pine stand, unaffected by wildfire and not thinned was used as a control. Physicochemical soil properties (soil texture, pH, carbonates, organic matter, electrical conductivity, total N and P), soil enzymes (urease, phosphatase, β-glucosidase and dehydrogenase activities), soil respiration and soil microbial biomass carbon were analysed in the selected forests areas and plots. The main finding was that long time after this fire event produces no differences in the microbiological soil properties and enzyme activities of soil after comparing burned and thinned, burned and not thinned, and mature plots. Moreover, significant site variation was generally seen in soil enzyme activities and microbiological parameters. We conclude that total vegetation recovery normalises post-fire soil microbial parameters, and that wildfire and post-fire silvicultural treatments are not significant factors affecting soil properties after 17 years.

  18. Louisiana's forests, 2013

    Treesearch

    Sonja N. Oswalt

    2016-01-01

    The principle findings of the 2013 forest survey in the State of Louisiana and changes that have occurred since previous surveysare presented. Topics examined include forest area, ownership, forest-type groups, stand structure, timber volume, growth, removals, and mortality. Emerald ash borer and invasive plants are also discussed in the context of...

  19. Pennsylvania forests 2014

    Treesearch

    Thomas A. Albright; William H. McWilliams; Richard H. Widmann; Brett J. Butler; Susan J. Crocker; Cassandra M. Kurtz; Shawn Lehman; Tonya W. Lister; Patrick D. Miles; Randall S. Morin; Rachel Riemann; James E. Smith

    2017-01-01

    This report summarizes the third cycle of annualized inventory of Pennsylvania with field data collected from 2009 through 2014. Pennsylvania has 16.9 million acres of forest land dominated by sawtimber stands of oak/hickory and maple/beech/birch forest-type groups. Volumes continue to increase as the forests age with an average of 2,244 cubic feet per acre on...

  20. Logging impacts on forest structure and seedling dynamics in a Prioria copaifera (Fabaceae) dominated tropical rain forest (Talamanca, Costa Rica).

    PubMed

    Valverde-Barrantes, Oscar J; Rocha, Oscar J

    2014-03-01

    The factors that determine the existence of tropical forests dominated by a single species (monodominated forests) have been the subject of debate for a long time. It has been hypothesized that the low frequency of disturbances in monodominated forests and the tolerance to shade of the monodominant species are two important factors explaining the prolonged dominance of a single species. We determined the role of these two factors by examining the effects of logging activities on the floristic composition and seedling dynamics in a Prioria copaifera dominated forest in Southeastern Costa Rica. We determined the floristic composition for trees > or = 2.5cm DBH and the associated recruitment, survival and mortality of tree canopy seedlings in two sites logged two (L-02) and 12 years (L-12) prior to sampling and an unlogged forest (ULF). Our results showed that L-02 stands had lower species richness (25 species) than the L-12 and ULF stands (49 and 46 species, respectively). As expected, we found significant logging effects on the canopy structure of the altered forests, particularly when comparing the L-02 and the ULF stands. Seedling density was higher in ULF (0.96 seedlings/ m2) than in the L-02 and L-12 stands (0.322 and 0.466 seedlings/m2, respectively). However, seedling mortality was higher in the ULF stands (54%) than in the L-02 (26%) and L-12 (15%) stands. P. macroloba in L-02 was the only species with abundant regeneration under P. copaifera in L-02 stand, where it accounted for 35% of the seedlings. Despite the reduction in seedling abundance observed after logging, P. copaifera seems to maintain large seedling populations in these forests, suggesting that this species maintains its dominance after logging disturbances. Our findings challenge the hypothesis that the regeneration of monodominant species is not likely to occur under heavily disturbed canopy conditions.