Modeling bidirectional reflectance of forests and woodlands using Boolean models and geometric optics

NASA Technical Reports Server (NTRS)

Strahler, Alan H.; Jupp, David L. B.

1990-01-01

Geometric-optical discrete-element mathematical models for forest canopies have been developed using the Boolean logic and models of Serra. The geometric-optical approach is considered to be particularly well suited to describing the bidirectional reflectance of forest woodland canopies, where the concentration of leaf material within crowns and the resulting between-tree gaps make plane-parallel, radiative-transfer models inappropriate. The approach leads to invertible formulations, in which the spatial and directional variance provides the means for remote estimation of tree crown size, shape, and total cover from remotedly sensed imagery.

A scalable approach for tree segmentation within small-footprint airborne LiDAR data

NASA Astrophysics Data System (ADS)

Hamraz, Hamid; Contreras, Marco A.; Zhang, Jun

2017-05-01

This paper presents a distributed approach that scales up to segment tree crowns within a LiDAR point cloud representing an arbitrarily large forested area. The approach uses a single-processor tree segmentation algorithm as a building block in order to process the data delivered in the shape of tiles in parallel. The distributed processing is performed in a master-slave manner, in which the master maintains the global map of the tiles and coordinates the slaves that segment tree crowns within and across the boundaries of the tiles. A minimal bias was introduced to the number of detected trees because of trees lying across the tile boundaries, which was quantified and adjusted for. Theoretical and experimental analyses of the runtime of the approach revealed a near linear speedup. The estimated number of trees categorized by crown class and the associated error margins as well as the height distribution of the detected trees aligned well with field estimations, verifying that the distributed approach works correctly. The approach enables providing information of individual tree locations and point cloud segments for a forest-level area in a timely manner, which can be used to create detailed remotely sensed forest inventories. Although the approach was presented for tree segmentation within LiDAR point clouds, the idea can also be generalized to scale up processing other big spatial datasets.

UrbanCrowns: an assessment and monitoring tool for urban trees

Treesearch

Matthew F. Winn; Philip A. Araman; Sang-Mook Lee

2011-01-01

UrbanCrowns is a Windows®-based computer program used to assess the crown characteristics of urban trees. The software analyzes side-view digital photographs of trees to compute several crown metrics, including crown height, crown diameter, live crown ratio, crown volume, crown density, and crown transparency. Potential uses of the UrbanCrowns program include...

Primary and Secondary Controls on Measurements of Forest Height Using Large-Footprint Lidar at the Hubbard Brook LTER

NASA Technical Reports Server (NTRS)

Knox, Robert G.; Blair, J. Bryan; Schwarz, Paul A.; Hofton, Michelle A.; Dubayah, Ralph; Smith, David E. (Technical Monitor)

2000-01-01

On September 26, 1999, we mapped canopy structure over 90% of the Hubbard Brook Experimental Forest in White Mountain National Forest, New Hampshire, using the Laser Vegetation Imaging Sensor (LVIS). This airborne instrument was configured to emulate data expected from the Vegetation Canopy Lidar (VCL) space mission. We compared above ground heights of the tallest surfaces detected by lidar with average forest canopy heights estimated from tree-based measurements in or near 346 0.05 ha plots (made in autumn of 1997 and 1998). Vegetation heights had by far the predominant influence on lidar top heights, but with this large data set we were able to measure two significant secondary effects: those of steepness or slope of the underlying terrain and of tree crown form. The size of the slope effect was intermediate between that expected from models of homogeneous canopy layers and for solitary tree crowns. The first detected surfaces were also proportionately taller for plots with more basal area in broad leaved northern hardwoods than for mostly coniferous plots. We expected this because of the contrast between the shapes of cumulative distributions of surface area for elliptical or hemi-elliptical tree crowns and those for conical crowns. Correcting for these secondary effects, when appropriate data are available for calibration, may improve vegetation structure estimates in regional studies using VCL or similar lidar data sources.

Vertical stratification of forest canopy for segmentation of understory trees within small-footprint airborne LiDAR point clouds

NASA Astrophysics Data System (ADS)

Hamraz, Hamid; Contreras, Marco A.; Zhang, Jun

2017-08-01

Airborne LiDAR point cloud representing a forest contains 3D data, from which vertical stand structure even of understory layers can be derived. This paper presents a tree segmentation approach for multi-story stands that stratifies the point cloud to canopy layers and segments individual tree crowns within each layer using a digital surface model based tree segmentation method. The novelty of the approach is the stratification procedure that separates the point cloud to an overstory and multiple understory tree canopy layers by analyzing vertical distributions of LiDAR points within overlapping locales. The procedure does not make a priori assumptions about the shape and size of the tree crowns and can, independent of the tree segmentation method, be utilized to vertically stratify tree crowns of forest canopies. We applied the proposed approach to the University of Kentucky Robinson Forest - a natural deciduous forest with complex and highly variable terrain and vegetation structure. The segmentation results showed that using the stratification procedure strongly improved detecting understory trees (from 46% to 68%) at the cost of introducing a fair number of over-segmented understory trees (increased from 1% to 16%), while barely affecting the overall segmentation quality of overstory trees. Results of vertical stratification of the canopy showed that the point density of understory canopy layers were suboptimal for performing a reasonable tree segmentation, suggesting that acquiring denser LiDAR point clouds would allow more improvements in segmenting understory trees. As shown by inspecting correlations of the results with forest structure, the segmentation approach is applicable to a variety of forest types.

Unsupervised individual tree crown detection in high-resolution satellite imagery

DOE PAGES

Skurikhin, Alexei N.; McDowell, Nate G.; Middleton, Richard S.

2016-01-26

Rapidly and accurately detecting individual tree crowns in satellite imagery is a critical need for monitoring and characterizing forest resources. We present a two-stage semiautomated approach for detecting individual tree crowns using high spatial resolution (0.6 m) satellite imagery. First, active contours are used to recognize tree canopy areas in a normalized difference vegetation index image. Given the image areas corresponding to tree canopies, we then identify individual tree crowns as local extrema points in the Laplacian of Gaussian scale-space pyramid. The approach simultaneously detects tree crown centers and estimates tree crown sizes, parameters critical to multiple ecosystem models. Asmore » a demonstration, we used a ground validated, 0.6 m resolution QuickBird image of a sparse forest site. The two-stage approach produced a tree count estimate with an accuracy of 78% for a naturally regenerating forest with irregularly spaced trees, a success rate equivalent to or better than existing approaches. In addition, our approach detects tree canopy areas and individual tree crowns in an unsupervised manner and helps identify overlapping crowns. Furthermore, the method also demonstrates significant potential for further improvement.« less

Unsupervised individual tree crown detection in high-resolution satellite imagery

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

Skurikhin, Alexei N.; McDowell, Nate G.; Middleton, Richard S.

Rapidly and accurately detecting individual tree crowns in satellite imagery is a critical need for monitoring and characterizing forest resources. We present a two-stage semiautomated approach for detecting individual tree crowns using high spatial resolution (0.6 m) satellite imagery. First, active contours are used to recognize tree canopy areas in a normalized difference vegetation index image. Given the image areas corresponding to tree canopies, we then identify individual tree crowns as local extrema points in the Laplacian of Gaussian scale-space pyramid. The approach simultaneously detects tree crown centers and estimates tree crown sizes, parameters critical to multiple ecosystem models. Asmore » a demonstration, we used a ground validated, 0.6 m resolution QuickBird image of a sparse forest site. The two-stage approach produced a tree count estimate with an accuracy of 78% for a naturally regenerating forest with irregularly spaced trees, a success rate equivalent to or better than existing approaches. In addition, our approach detects tree canopy areas and individual tree crowns in an unsupervised manner and helps identify overlapping crowns. Furthermore, the method also demonstrates significant potential for further improvement.« less

Individual tree crown delineation using localized contour tree method and airborne LiDAR data in coniferous forests

NASA Astrophysics Data System (ADS)

Wu, Bin; Yu, Bailang; Wu, Qiusheng; Huang, Yan; Chen, Zuoqi; Wu, Jianping

2016-10-01

Individual tree crown delineation is of great importance for forest inventory and management. The increasing availability of high-resolution airborne light detection and ranging (LiDAR) data makes it possible to delineate the crown structure of individual trees and deduce their geometric properties with high accuracy. In this study, we developed an automated segmentation method that is able to fully utilize high-resolution LiDAR data for detecting, extracting, and characterizing individual tree crowns with a multitude of geometric and topological properties. The proposed approach captures topological structure of forest and quantifies topological relationships of tree crowns by using a graph theory-based localized contour tree method, and finally segments individual tree crowns by analogy of recognizing hills from a topographic map. This approach consists of five key technical components: (1) derivation of canopy height model from airborne LiDAR data; (2) generation of contours based on the canopy height model; (3) extraction of hierarchical structures of tree crowns using the localized contour tree method; (4) delineation of individual tree crowns by segmenting hierarchical crown structure; and (5) calculation of geometric and topological properties of individual trees. We applied our new method to the Medicine Bow National Forest in the southwest of Laramie, Wyoming and the HJ Andrews Experimental Forest in the central portion of the Cascade Range of Oregon, U.S. The results reveal that the overall accuracy of individual tree crown delineation for the two study areas achieved 94.21% and 75.07%, respectively. Our method holds great potential for segmenting individual tree crowns under various forest conditions. Furthermore, the geometric and topological attributes derived from our method provide comprehensive and essential information for forest management.

Tree crown conditions in Missouri, 2000-2003

Treesearch

KaDonna C. Randolph; W. Keith Moser

2009-01-01

The Forest Service, U.S. Department of Agriculture, Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes three FIA tree crown condition indicators (crown dieback, crown density, and foliage transparency) and sapling crown vigor measured in Missouri between 2000...

Equations for predicting uncompacted crown ratio based on compacted crown ratio and tree attributes.

Treesearch

Vicente J. Monleon; David Azuma; Donald Gedney

2004-01-01

Equations to predict uncompacted crown ratio as a function of compacted crown ratio, tree diameter, and tree height are developed for the main tree species in Oregon, Washington, and California using data from the Forest Health Monitoring Program, USDA Forest Service. The uncompacted crown ratio was modeled with a logistic function and fitted using weighted, nonlinear...

Tree crown mapping in managed woodlands (parklands) of semi-arid West Africa using WorldView-2 imagery and geographic object based image analysis.

PubMed

Karlson, Martin; Reese, Heather; Ostwald, Madelene

2014-11-28

Detailed information on tree cover structure is critical for research and monitoring programs targeting African woodlands, including agroforestry parklands. High spatial resolution satellite imagery represents a potentially effective alternative to field-based surveys, but requires the development of accurate methods to automate information extraction. This study presents a method for tree crown mapping based on Geographic Object Based Image Analysis (GEOBIA) that use spectral and geometric information to detect and delineate individual tree crowns and crown clusters. The method was implemented on a WorldView-2 image acquired over the parklands of Saponé, Burkina Faso, and rigorously evaluated against field reference data. The overall detection rate was 85.4% for individual tree crowns and crown clusters, with lower accuracies in areas with high tree density and dense understory vegetation. The overall delineation error (expressed as the difference between area of delineated object and crown area measured in the field) was 45.6% for individual tree crowns and 61.5% for crown clusters. Delineation accuracies were higher for medium (35-100 m(2)) and large (≥100 m(2)) trees compared to small (<35 m(2)) trees. The results indicate potential of GEOBIA and WorldView-2 imagery for tree crown mapping in parkland landscapes and similar woodland areas.

Tree Crown Mapping in Managed Woodlands (Parklands) of Semi-Arid West Africa Using WorldView-2 Imagery and Geographic Object Based Image Analysis

PubMed Central

Karlson, Martin; Reese, Heather; Ostwald, Madelene

2014-01-01

Detailed information on tree cover structure is critical for research and monitoring programs targeting African woodlands, including agroforestry parklands. High spatial resolution satellite imagery represents a potentially effective alternative to field-based surveys, but requires the development of accurate methods to automate information extraction. This study presents a method for tree crown mapping based on Geographic Object Based Image Analysis (GEOBIA) that use spectral and geometric information to detect and delineate individual tree crowns and crown clusters. The method was implemented on a WorldView-2 image acquired over the parklands of Saponé, Burkina Faso, and rigorously evaluated against field reference data. The overall detection rate was 85.4% for individual tree crowns and crown clusters, with lower accuracies in areas with high tree density and dense understory vegetation. The overall delineation error (expressed as the difference between area of delineated object and crown area measured in the field) was 45.6% for individual tree crowns and 61.5% for crown clusters. Delineation accuracies were higher for medium (35–100 m2) and large (≥100 m2) trees compared to small (<35 m2) trees. The results indicate potential of GEOBIA and WorldView-2 imagery for tree crown mapping in parkland landscapes and similar woodland areas. PMID:25460815

Descriptive statistics of tree crown condition in California, Oregon, and Washington

Treesearch

KaDonna C. Randolph; Sally J. Campbell; Glenn Christensen

2010-01-01

The U.S. Forest Service Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes four tree crown condition indicators (crown dieback, crown density, foliage transparency, and sapling crown vigor) measured in California, Oregon, and Washington between 1996 and 1999....

Influence of micro-topography and crown characteristics on tree height estimations in tropical forests based on LiDAR canopy height models

NASA Astrophysics Data System (ADS)

Alexander, Cici; Korstjens, Amanda H.; Hill, Ross A.

2018-03-01

Tree or canopy height is an important attribute for carbon stock estimation, forest management and habitat quality assessment. Airborne Laser Scanning (ALS) based on Light Detection and Ranging (LiDAR) has advantages over other remote sensing techniques for describing the structure of forests. However, sloped terrain can be challenging for accurate estimation of tree locations and heights based on a Canopy Height Model (CHM) generated from ALS data; a CHM is a height-normalised Digital Surface Model (DSM) obtained by subtracting a Digital Terrain Model (DTM) from a DSM. On sloped terrain, points at the same elevation on a tree crown appear to increase in height in the downhill direction, based on the ground elevations at these points. A point will be incorrectly identified as the treetop by individual tree crown (ITC) recognition algorithms if its height is greater than that of the actual treetop in the CHM, which will be recorded as the tree height. In this study, the influence of terrain slope and crown characteristics on the detection of treetops and estimation of tree heights is assessed using ALS data in a tropical forest with complex terrain (i.e. micro-topography) and tree crown characteristics. Locations and heights of 11,442 trees based on a DSM are compared with those based on a CHM. The horizontal (DH) and vertical displacements (DV) increase with terrain slope (r = 0.47 and r = 0.54 respectively, p < 0.001). The overestimations in tree height are up to 16.6 m on slopes greater than 50° in our study area in Sumatra. The errors in locations (DH) and tree heights (DV) are modelled for trees with conical and spherical tree crowns. For a spherical tree crown, DH can be modelled as R sin θ, and DV as R (sec θ - 1). In this study, a model is developed for an idealised conical tree crown, DV = R (tan θ - tan ψ), where R is the crown radius, and θ and ψ are terrain and crown angles respectively. It is shown that errors occur only when terrain angle exceeds the crown angle, with the horizontal displacement equal to the crown radius. Errors in location are seen to be greater for spherical than conical trees on slopes where crown angles of conical trees are less than the terrain angle. The results are especially relevant for biomass and carbon stock estimations in tropical forests where there are trees with large crown radii on slopes.

A landscape perspective for forest restoration

USGS Publications Warehouse

Sisk, Thomas D.; Savage, Melissa; Falk, Donald A.; Allen, Craig D.; Muldavin, Esteban; McCarthy, Patrick

2005-01-01

Forest managers throughout the West are anxiously seeking solutions to the problem of “large crown fires” - destructive blazes atypical of many forest types in the region. These wildfires have created a crisis mentality in management that has focused on rigid prescriptions for fuels reduction, rather than the restoration of diverse, resilient, and self-regulating forest ecosystems. Now, as we shape our responses to the threat of larger and more frequent crown fires, we are in danger of missing the forest for the trees.

Coordination of crown structure, leaf plasticity and carbon gain within the crowns of three winter-deciduous mature trees.

PubMed

Uemura, Akira; Harayama, Hisanori; Koike, Nobuya; Ishida, Atsushi

2006-05-01

We examined the vertical profiles of leaf characteristics within the crowns of two late-successional (Fagus crenata Blume and Fagus japonica Maxim.) and one early-successional tree species (Betula grossa Sieb. et Zucc.) in a Japanese forest. We also assessed the contributions of the leaves in each crown layer to whole-crown instantaneous carbon gain at midday. Carbon gain was estimated from the relationship between electron transport and photosynthetic rates. We hypothesized that more irradiance can penetrate into the middle of the crown if the upper crown layers have steep leaf inclination angles. We found that such a crown has a high whole-crown carbon gain, even if leaf traits do not change greatly with decreasing crown height. Leaf area indices (LAIs) of the two Fagus trees (5.26-5.52) were higher than the LAI of the B. grossa tree (4.50) and the leaves of the F. crenata tree were more concentrated in the top crown layers than were leaves of the other trees. Whole-crown carbon gain per unit ground area (micromol m(-2) ground s(-1)) at midday on fine days in summer was 16.3 for F. crenata, 11.0 for F. japonica, and 20.4 for B. grossa. In all study trees, leaf dry mass (LMA) and leaf nitrogen content (N) per unit area decreased with decreasing height in the crown, but leaf N per unit mass increased. Variations (plasticity) between the uppermost and lowermost crown layers in LMA, leaf N, the ratio of chlorophyll to N and the ratio of chlorophyll a to b were smaller for F. japonica and B. grossa than for F. crenata. The light extinction coefficients in the crowns were lower for the F. japonica and B. grossa trees than for the F. crenata tree. The leaf carbon isotope ratio (delta(13)C) was higher for F. japonica and B. grossa than for F. crenata, especially in the mid-crown. These results suggest that, in crowns with low leaf plasticity but steep leaf inclination angles, such as those of F. japonica and B. grossa trees, irradiance can penetrate into the middle of the crowns, thereby enhancing whole-crown carbon gain.

Equations to convert compacted crown ratio to uncompacted crown ratio for trees in the Interior West

Treesearch

Chris Toney; Matthew C. Reeves

2009-01-01

Crown ratio is the proportion of total tree length supporting live foliage. Inventory programs of the US Forest Service generally define crown ratio in terms of compacted or uncompacted measurements. Measurement of compacted crown ratio (CCR) involves envisioning the transfer of lower branches of trees with asymmetric crowns to fill holes in the upper portion of the...

Relation of Crown Width to Tree Diameter In Some Upland Hardwood Stands of Southern Illinois

Treesearch

Leon S. Minckler; Samuel F. Gingrich

1970-01-01

Crown width-d.b.h. relationships in well stocked, uneven-aged stands of oak and hickory were similar to those for open-grown trees and were independent of site, crown class, and species. The irregular crowns of forest grown trees interface and overlap, however, and measuring crown extensions to the branch tips tended to overestimate effective crown area

Tree crown structure indicators in a natural uneven-aged mixed coniferous forest in northeastern Mexico

Treesearch

Javier Jimenez-Perez; Oscar Aguirre-Calderon; Horst Kramer

2006-01-01

Characterization of tree crown structure provides critical information to assess a variety of ecological conditions for multiple purposes and applications. For biomass growth, for example, tree crowns have basic physiological functions: assimilation, respiration, and transpiration. How tree crowns spatially interact and grow can bring about a seamless landscape of...

Not All Trees Sleep the Same—High Temporal Resolution Terrestrial Laser Scanning Shows Differences in Nocturnal Plant Movement

PubMed Central

Zlinszky, András; Molnár, Bence; Barfod, Anders S.

2017-01-01

Circadian leaf movements are widely known in plants, but nocturnal movement of tree branches were only recently discovered by using terrestrial laser scanning (TLS), a high resolution three-dimensional surveying technique. TLS uses a pulsed laser emitted in a regular scan pattern for rapid measurement of distances to the targets, thus producing three dimensional point cloud models of sub-centimeter resolution and accuracy in a few minutes. Here, we aim to gain an overview of the variability of circadian movement of small trees across different taxonomic groups, growth forms and leaf anatomies. We surveyed a series of 18 full scans over a 12-h night period to measure nocturnal changes in shape simultaneously for an experimental setup of 22 plants representing different species. Resulting point clouds were evaluated by comparing changes in height percentiles of laser scanning points belonging to the canopy. Changes in crown shape were observed for all studied trees, but clearly distinguishable sleep movements are apparently rare. Ambient light conditions were continuously dark between sunset (7:30 p.m.) and sunrise (6:00 a.m.), but most changes in movement direction occurred during this period, thus most of the recorded changes in crown shape were probably not controlled by ambient light. The highest movement amplitudes, for periodic circadian movement around 2 cm were observed for Aesculus and Acer, compared to non-periodic continuous change in shape of 5 cm for Gleditschia and 2 cm for Fargesia. In several species we detected 2–4 h cycles of minor crown movement of 0.5–1 cm, which is close to the limit of our measurement accuracy. We present a conceptual framework for interpreting observed changes as a combination of circadian rhythm with a period close to 12 h, short-term oscillation repeated every 2–4 h, aperiodic continuous movement in one direction and measurement noise which we assume to be random. Observed movement patterns are interpreted within this framework, and connections with morphology and taxonomy are proposed. We confirm the existence of overnight “sleep” movement for some trees, but conclude that circadian movement is a variable phenomenon in plants, probably controlled by a complex combination of anatomical, physiological, and morphological factors. PMID:29104583

Relationships of tree height and diameter at breast height revisited: analyses of stem growth using 20-year data of an even-aged Chamaecyparis obtusa stand

PubMed Central

Sumida, Akihiro; Miyaura, Tomiyasu; Torii, Hitoshi

2013-01-01

Stem diameter at breast height (DBH) and tree height (H) are commonly used measures of tree growth. We examined patterns of height growth and diameter growth along a stem using a 20-year record of an even-aged hinoki cypress (Chamaecyparis obtusa (Siebold & Zucc.) Endl.) stand. In the region of the stem below the crown (except for the butt swell), diameter growth rates (ΔD) at different heights tended to increase slightly from breast height upwards. This increasing trend was pronounced in suppressed trees, but not as much as the variation in ΔD among individual trees. Hence, ΔD below the crown can be regarded as generally being represented by the DBH growth rate (ΔDBH) of a tree. Accordingly, the growth rate of the stem cross-sectional area increased along the stem upwards in suppressed trees, but decreased in dominant trees. The stem diameter just below the crown base (DCB), the square of which is an index of the amount of leaves on a tree, was an important factor affecting ΔDBH. DCB also had a strong positive relationship with crown length. Hence, long-term changes in the DCB of a tree were associated with long-term changes in crown length, determined by the balance between the height growth rate (ΔH) and the rising rate of the crown base (ΔHCB). Within the crown, ΔD's were generally greater than the rates below the crown. Even dying trees (ΔD ≈ 0 below the crown) maintained ΔD > 0 within the crown and ΔH > 0 until about 5 years before death. This growth within the crown may be related to the need to produce new leaves to compensate for leaves lost owing to the longevity of the lower crown. These results explain the different time trajectories in DBH–H relationships among individual trees, and also the long-term changes in the DBH–H relationships. The view that a rise in the crown base is strongly related to leaf turnover helps to interpret DBH–H relationships. PMID:23303367

Descriptive statistics of tree crown condition in the Southern United States and impacts on data analysis and interpretation

Treesearch

KaDonna C. Randolph

2006-01-01

The U.S. Department of Agriculture Forest Service, Forest Inventory and Analysis Program (FIA) utilizes visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes and discusses distributions of three FIA crown condition indicators (crown density, crown dieback, and foliage transparency) for trees in the Southern...

Chapter 7 - Crown condition

Treesearch

KaDonna C. Randolph

2018-01-01

Tree crown conditions are visually assessed by the U.S. Department of Agriculture, Forest Service, Forest Inventory and Analysis (FIA) Program as an indicator of forest health. These assessments are useful because individual tree photosynthetic capacity is dependent upon the size and condition of the crown. In general, trees with full, vigorous crowns are associated...

Crown condition dynamics of oak in southern Sweden 1988-1999.

PubMed

Drobyshev, Igor; Anderson, Stefan; Sonesson, Kerstin

2007-11-01

Crown defoliation of oak (Quercus robur and Q. petraea) was analysed in 808 trees during three forest condition surveys (1988, 1993, and 1999) in the southern Sweden. From 1988 to 1999 crown defoliation increased by more than 20%. Changes in crown defoliation were related to the pH in the upper 20-30 cm of the mineral soils, which was closely connected to other measures of soil fertility (cation exchange capacity, CEC and C/N ratio). Trees growing on soils with a high pH (> or =4.00, in BaCl2 filtrate), high CEC and low C/N ratio had significantly lower crown defoliation than trees growing on more acid soils (pH <4.00), indicating that less favourable soil conditions may further enhance oak decline. Age did not differentiate trees with respect to crown defoliation, indicating that decline in crown condition was not due to an age-related increase in crown transparency. Considering only trees younger than 100 years, a significant interaction was observed between changes in crown defoliation and soil pH. Trees younger than 100 years old growing on more acidic soils had a greater increase in crown transparency than trees on more basic soils between 1988 and 1999. Trees > or =100 years old had significantly higher defoliation on more acidic than on more basic soils, however defoliation dynamics of these trees over 1988-99 was not related to soil acidity. Two biotic agents (insect and fungal leaf infections) evaluated in this study did not prove to be important drivers of defoliation dynamics.

A tree canopy height delineation method based on Morphological Reconstruction—Open Crown Decomposition

NASA Astrophysics Data System (ADS)

Liu, Q.; Jing, L.; Li, Y.; Tang, Y.; Li, H.; Lin, Q.

2016-04-01

For the purpose of forest management, high resolution LIDAR and optical remote sensing imageries are used for treetop detection, tree crown delineation, and classification. The purpose of this study is to develop a self-adjusted dominant scales calculation method and a new crown horizontal cutting method of tree canopy height model (CHM) to detect and delineate tree crowns from LIDAR, under the hypothesis that a treetop is radiometric or altitudinal maximum and tree crowns consist of multi-scale branches. The major concept of the method is to develop an automatic selecting strategy of feature scale on CHM, and a multi-scale morphological reconstruction-open crown decomposition (MRCD) to get morphological multi-scale features of CHM by: cutting CHM from treetop to the ground; analysing and refining the dominant multiple scales with differential horizontal profiles to get treetops; segmenting LiDAR CHM using watershed a segmentation approach marked with MRCD treetops. This method has solved the problems of false detection of CHM side-surface extracted by the traditional morphological opening canopy segment (MOCS) method. The novel MRCD delineates more accurate and quantitative multi-scale features of CHM, and enables more accurate detection and segmentation of treetops and crown. Besides, the MRCD method can also be extended to high optical remote sensing tree crown extraction. In an experiment on aerial LiDAR CHM of a forest of multi-scale tree crowns, the proposed method yielded high-quality tree crown maps.

Crown Release Promotes Faster Diameter Growth of Pole-Size Black Walnut

Treesearch

Robert E. Phares; Robert D. Williams

1971-01-01

Complete crown release more than doubles the diameter growth of pole-size black walnut trees in southern Indiana over a 10-year period. Partially released trees gew about 50 percent more than unreleased trees. The faster growth of the released trees was directly related to increases in crown-area expansion. Most of the study trees produced bole sprouts; however, the...

Equations for predicting diameter, height, crown width, and leaf area of San Joaquin Valley street trees

Treesearch

P.J. Peper; E.G. McPherson; S.M. Mori

2001-01-01

Although the modeling of energy-use reduction, air pollution uptake, rainfall interception, and microclimate modification associated with urban trees depends on data relating diameter at breast height (dbh) , crown height, crown diameter, and leaf area to tree age or dbh, scant information is available for common municipal tree species . I n this study , tree height ,...

Utility of tree crown condition indicators to predict tree survival using remeasured Forest Inventory and Analysis data

Treesearch

Randall S. Morin; Jim Steinman; KaDonna C. Randolph

2012-01-01

The condition of tree crowns is an important indicator of tree and forest health. Crown conditions have been evaluated during surveys of Forest Inventory and Analysis (FIA) Phase 3 (P3) plots since 1999. In this study, remeasured data from 39,357 trees in the northern United States were used to assess the probability of survival among various tree species using the...

Crown radius and diameter at breast height relationships for six bottomland hardwood species

Treesearch

Brian Roy Lockhart; Robert C. Weih; Keith M. Smith

2005-01-01

The relationship between a tree's crown radius and diameter at breast height (DBH) has a variety of uses including forest competition studies, tree crown densities, spacing and stocking relationships, wildlife habitat suitability models, and tree volume estimations. Estimating DBH from mean crown radius (MCR) is of interest to natural resource managers because MCR...

Descriptive statistics of tree crown condition in the Northeastern United States

Treesearch

KaDonna C. Randolph; Randall S. Morin; Jim Steinman

2010-01-01

The U.S. Forest Service Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes four crown condition indicators (crown dieback, crown density, foliage transparency, and sapling crown vigor) measured in Connecticut, Delaware, Maine, Maryland, Massachusetts, New...

Comparison of the arithmetic and geometric means in estimating crown diameter and crown cross-sectional area

Treesearch

KaDonna Randolph

2010-01-01

The use of the geometric and arithmetic means for estimating tree crown diameter and crown cross-sectional area were examined for trees with crown width measurements taken at the widest point of the crown and perpendicular to the widest point of the crown. The average difference between the geometric and arithmetic mean crown diameters was less than 0.2 ft in absolute...

Automatic determination of trunk diameter, crown base and height of scots pine (Pinus Sylvestris L.) Based on analysis of 3D point clouds gathered from multi-station terrestrial laser scanning. (Polish Title: Automatyczne okreslanie srednicy pnia, podstawy korony oraz wysokosci sosny zwyczajnej (Pinus Silvestris L.) Na podstawie analiz chmur punktow 3D pochodzacych z wielostanowiskowego naziemnego skanowania laserowego)

NASA Astrophysics Data System (ADS)

Ratajczak, M.; Wężyk, P.

2015-12-01

Rapid development of terrestrial laser scanning (TLS) in recent years resulted in its recognition and implementation in many industries, including forestry and nature conservation. The use of the 3D TLS point clouds in the process of inventory of trees and stands, as well as in the determination of their biometric features (trunk diameter, tree height, crown base, number of trunk shapes), trees and lumber size (volume of trees) is slowly becoming a practice. In addition to the measurement precision, the primary added value of TLS is the ability to automate the processing of the clouds of points 3D in the direction of the extraction of selected features of trees and stands. The paper presents the original software (GNOM) for the automatic measurement of selected features of trees, based on the cloud of points obtained by the ground laser scanner FARO. With the developed algorithms (GNOM), the location of tree trunks on the circular research surface was specified and the measurement was performed; the measurement covered the DBH (l: 1.3m), further diameters of tree trunks at different heights of the tree trunk, base of the tree crown and volume of the tree trunk (the selection measurement method), as well as the tree crown. Research works were performed in the territory of the Niepolomice Forest in an unmixed pine stand (Pinussylvestris L.) on the circular surface with a radius of 18 m, within which there were 16 pine trees (14 of them were cut down). It was characterized by a two-storey and even-aged construction (147 years old) and was devoid of undergrowth. Ground scanning was performed just before harvesting. The DBH of 16 pine trees was specified in a fully automatic way, using the algorithm GNOM with an accuracy of +2.1%, as compared to the reference measurement by the DBH measurement device. The medium, absolute measurement error in the cloud of points - using semi-automatic methods "PIXEL" (between points) and PIPE (fitting the cylinder) in the FARO Scene 5.x., showed the error, 3.5% and 5.0%,.respectively The reference height was assumed as the measurement performed by the tape on the cut tree. The average error of automatic determination of the tree height by the algorithm GNOM based on the TLS point clouds amounted to 6.3% and was slightly higher than when using the manual method of measurements on profiles in the TerraScan (Terrasolid; the error of 5.6%). The relatively high value of the error may be mainly related to the small number of points TLS in the upper parts of crowns. The crown height measurement showed the error of +9.5%. The reference in this case was the tape measurement performed already on the trunks of cut pine trees. Processing the clouds of points by the algorithms GNOM for 16 analyzed trees took no longer than 10 min. (37 sec. /tree). The paper mainly showed the TLS measurement innovation and its high precision in acquiring biometric data in forestry, and at the same time also the further need to increase the degree of automation of processing the clouds of points 3D from terrestrial laser scanning.

Mortality rates associated with crown health for eastern forest tree species

Treesearch

Randall S. Morin; KaDonna C. Randolph; Jim Steinman

2015-01-01

The condition of tree crowns is an important indicator of tree and forest health. Crown conditions have been evaluated during inventories of the US Forest Service Forest Inventory and Analysis (FIA) program since 1999. In this study, remeasured data from 55,013 trees on 2616 FIA plots in the eastern USA were used to assess the probability of survival among various tree...

A Lidar Point Cloud Based Procedure for Vertical Canopy Structure Analysis And 3D Single Tree Modelling in Forest

PubMed Central

Wang, Yunsheng; Weinacker, Holger; Koch, Barbara

2008-01-01

A procedure for both vertical canopy structure analysis and 3D single tree modelling based on Lidar point cloud is presented in this paper. The whole area of research is segmented into small study cells by a raster net. For each cell, a normalized point cloud whose point heights represent the absolute heights of the ground objects is generated from the original Lidar raw point cloud. The main tree canopy layers and the height ranges of the layers are detected according to a statistical analysis of the height distribution probability of the normalized raw points. For the 3D modelling of individual trees, individual trees are detected and delineated not only from the top canopy layer but also from the sub canopy layer. The normalized points are resampled into a local voxel space. A series of horizontal 2D projection images at the different height levels are then generated respect to the voxel space. Tree crown regions are detected from the projection images. Individual trees are then extracted by means of a pre-order forest traversal process through all the tree crown regions at the different height levels. Finally, 3D tree crown models of the extracted individual trees are reconstructed. With further analyses on the 3D models of individual tree crowns, important parameters such as crown height range, crown volume and crown contours at the different height levels can be derived. PMID:27879916

Estimating tree crown widths for the primary Acadian species in Maine

Treesearch

Matthew B. Russell; Aaron R. Weiskittel

2012-01-01

In this analysis, data for seven conifer and eight hardwood species were gathered from across the state of Maine for estimating tree crown widths. Maximum and largest crown width equations were developed using tree diameter at breast height as the primary predicting variable. Quantile regression techniques were used to estimate the maximum crown width and a constrained...

Descriptive statistics of tree crown condition in the North Central United States

Treesearch

KaDonna C. Randolph; Randall S. Morin; Jim Steinman

2010-01-01

The U.S. Forest Service Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes four crown condition indicators (crown dieback, crown density, foliage transparency, and sapling crown vigor) measured in Illinois, Indiana, Michigan, Minnesota, Missouri, and Wisconsin...

Descriptive statistics of tree crown condition in the United States Interior West

Treesearch

KaDonna C. Randolph; Mike T. Thompson

2010-01-01

The U.S. Forest Service Forest Inventory and Analysis (FIA) Program uses visual assessments of tree crown condition to monitor changes and trends in forest health. This report describes four crown condition indicators (crown dieback, crown density, foliage transparency, and sapling crown vigor) measured in Colorado, Idaho, Nevada, Utah, and Wyoming between 1996 and...

Crown Position and Light Exposure Classification-An Alternative to Field-Assigned Crown Class

Treesearch

William A. Bechtold

2003-01-01

Crown class, an ordinal tree-level mensuration attribute used extensively by foresters, is difficult to assign in the field because definitions of individual classes are confounded by ambiguous references to the position the tree in the canopy and amount of light received by its crown. When crown class is decomposed into its two elements-crown position and crown light...

Crown Condition

Treesearch

KaDonna C. Randolph

2009-01-01

Photosynthetic capacity is dependent upon the size and condition of the tree crown. Trees with full, vigorous crowns are generally associated with more vigorous growth rates (Zarnoch and others 2004). Therefore, the Forest Service Forest Inventory and Analysis (FIA) Program measures a suite of crown condition indicators to evaluate forest health. Among the crown...

The expression of light-related leaf functional traits depends on the location of individual leaves within the crown of isolated Olea europaea trees

PubMed Central

Escribano-Rocafort, Adrián G.; Ventre-Lespiaucq, Agustina B.; Granado-Yela, Carlos; Rubio de Casas, Rafael; Delgado, Juan A.; Balaguer, Luis

2016-01-01

Background The spatial arrangement and expression of foliar syndromes within tree crowns can reflect the coupling between crown form and function in a given environment. Isolated trees subjected to high irradiance and concomitant stress may adjust leaf phenotypes to cope with environmental gradients that are heterogeneous in space and time within the tree crown. The distinct expression of leaf phenotypes among crown positions could lead to complementary patterns in light interception at the crown scale. Methods We quantified eight light-related leaf traits across 12 crown positions of ten isolated Olea europaea trees in the field. Specifically, we investigated whether the phenotypic expression of foliar traits differed among crown sectors and layers and five periods of the day from sunrise to sunset. We investigated the consequences in terms of the exposed area of the leaves at the tree scale during a single day. Key Results All traits differed among crown positions except the length-to-width ratio of the leaves. We found a strong complementarity in the patterns of the potential exposed area of the leaves among day periods as a result of a non-random distribution of leaf angles across the crown. Leaf exposure at the outer layer was below 60 % of the displayed surface, reaching maximum interception during morning periods. Daily interception increased towards the inner layer, achieving consecutive maximization from east to west positions within the crown, matching the sun’s trajectory. Conclusions The expression of leaf traits within isolated trees of O. europaea varies continuously through the crown in a gradient of leaf morphotypes and leaf angles depending on the exposure and location of individual leaves. The distribution of light-related traits within the crown and the complementarity in the potential exposure patterns of the leaves during the day challenges the assumption of low trait variability within individuals. PMID:26944783

Tree Crown Foliage Loss: A Mapping Survey on the Cumbrian Coast.

ERIC Educational Resources Information Center

Gilbertson, D. D.; Pyatt, F. B.

1980-01-01

An undergraduate student mapping survey of tree crown foliage loss is presented. Results suggest that the pattern and intensity of crown foliage loss of certain trees and shrubs in the Whitehaven area are affected by strong, salt-laden winds and air pollution. (CS)

Interpreting Michigan forest cover types from color infrared aerial photographs

NASA Technical Reports Server (NTRS)

Hudson, W. D.

1984-01-01

The characteristics of 17 cover types (13 forest types or tree species and 4 nonforest cover types) in Michigan are discussed as well as their interpretation from medium scale color infrared photography. The occurrence of each type is described by region and site requirements. Those attributes of a tree or stand which are helpful when attempting to interpret the type from a vertical perspective are discussed as well as common crown types. The identification of the forest type or tree species by using image characteristics (size, shape, shadow, color, texture, pattern, or association) is discussed. Ground photographs and sketches of individual trees are included. Stereograms of typical stands are available.

Crown characteristics of several coniferous tree species: relations between weight of crown, branchwood and foliage and stem diameter

Treesearch

Theodore G Storey; Wallace L. Fons; F.M. Sauer

1955-01-01

Prediction of wind breakage and uprooting in tree stands requires information on weight of dry crown, branchwood, and foliage. This information has not been published. An experimental program started in 1951 has led to a number of generalized relations by which these crown characteristics can be determined with good accuracy over a wide range of tree diameters, species...

Tree mortality risk of oak due to gypsy moth

Treesearch

K.W. Gottschalk; J.J. Colbert; D.L. Feicht

1998-01-01

We present prediction models for estimating tree mortality resulting from gypsy moth, Lymantria dispar, defoliation in mixed oak, Quercus sp., forests. These models differ from previous work by including defoliation as a factor in the analysis. Defoliation intensity, initial tree crown condition (crown vigour), crown position, and...

Comparative height crown allometry and mechanical design in 22 tree species of Kuala Belalong rainforest, Brunei, Borneo.

PubMed

Osunkoya, Olusegun O; Omar-Ali, Kharunnisa; Amit, Norratna; Dayan, Juita; Daud, Dayanawati S; Sheng, Tan K

2007-12-01

In rainforests, trunk size, strength, crown position, and geometry of a tree affect light interception and the likelihood of mechanical failure. Allometric relationships of tree diameter, wood density, and crown architecture vs. height are described for a diverse range of rainforest trees in Brunei, northern Borneo. The understory species follow a geometric model in their diameter-height relationship (slope, β = 1.08), while the stress-elasticity models prevail (β = 1.27-1.61) for the midcanopy and canopy/emergent species. These relationships changed with ontogeny, especially for the understory species. Within species, the tree stability safety factor (SSF) and relative crown width decreased exponentially with increasing tree height. These trends failed to emerge in across-species comparisons and were reversed at a common (low) height. Across species, the relative crown depth decreased with maximum potential height and was indistinguishable at a common (low) height. Crown architectural traits influence SSF more than structural property of wood density. These findings emphasize the importance of applying a common reference size in comparative studies and suggest that forest trees (especially the understory group) may adapt to low light by having deeper rather than wider crowns due to an efficient distribution and geometry of their foliage.

Mapping and characterizing selected canopy tree species at the Angkor World Heritage site in Cambodia using aerial data.

PubMed

Singh, Minerva; Evans, Damian; Tan, Boun Suy; Nin, Chan Samean

2015-01-01

At present, there is very limited information on the ecology, distribution, and structure of Cambodia's tree species to warrant suitable conservation measures. The aim of this study was to assess various methods of analysis of aerial imagery for characterization of the forest mensuration variables (i.e., tree height and crown width) of selected tree species found in the forested region around the temples of Angkor Thom, Cambodia. Object-based image analysis (OBIA) was used (using multiresolution segmentation) to delineate individual tree crowns from very-high-resolution (VHR) aerial imagery and light detection and ranging (LiDAR) data. Crown width and tree height values that were extracted using multiresolution segmentation showed a high level of congruence with field-measured values of the trees (Spearman's rho 0.782 and 0.589, respectively). Individual tree crowns that were delineated from aerial imagery using multiresolution segmentation had a high level of segmentation accuracy (69.22%), whereas tree crowns delineated using watershed segmentation underestimated the field-measured tree crown widths. Both spectral angle mapper (SAM) and maximum likelihood (ML) classifications were applied to the aerial imagery for mapping of selected tree species. The latter was found to be more suitable for tree species classification. Individual tree species were identified with high accuracy. Inclusion of textural information further improved species identification, albeit marginally. Our findings suggest that VHR aerial imagery, in conjunction with OBIA-based segmentation methods (such as multiresolution segmentation) and supervised classification techniques are useful for tree species mapping and for studies of the forest mensuration variables.

Mapping and Characterizing Selected Canopy Tree Species at the Angkor World Heritage Site in Cambodia Using Aerial Data

PubMed Central

Singh, Minerva; Evans, Damian; Tan, Boun Suy; Nin, Chan Samean

2015-01-01

At present, there is very limited information on the ecology, distribution, and structure of Cambodia’s tree species to warrant suitable conservation measures. The aim of this study was to assess various methods of analysis of aerial imagery for characterization of the forest mensuration variables (i.e., tree height and crown width) of selected tree species found in the forested region around the temples of Angkor Thom, Cambodia. Object-based image analysis (OBIA) was used (using multiresolution segmentation) to delineate individual tree crowns from very-high-resolution (VHR) aerial imagery and light detection and ranging (LiDAR) data. Crown width and tree height values that were extracted using multiresolution segmentation showed a high level of congruence with field-measured values of the trees (Spearman’s rho 0.782 and 0.589, respectively). Individual tree crowns that were delineated from aerial imagery using multiresolution segmentation had a high level of segmentation accuracy (69.22%), whereas tree crowns delineated using watershed segmentation underestimated the field-measured tree crown widths. Both spectral angle mapper (SAM) and maximum likelihood (ML) classifications were applied to the aerial imagery for mapping of selected tree species. The latter was found to be more suitable for tree species classification. Individual tree species were identified with high accuracy. Inclusion of textural information further improved species identification, albeit marginally. Our findings suggest that VHR aerial imagery, in conjunction with OBIA-based segmentation methods (such as multiresolution segmentation) and supervised classification techniques are useful for tree species mapping and for studies of the forest mensuration variables. PMID:25902148

Leaf traits in relation to crown development, light interception and growth of elite families of loblolly and slash pine.

PubMed

Chmura, Daniel J; Tjoelker, Mark G

2008-05-01

Crown architecture and size influence leaf area distribution within tree crowns and have large effects on the light environment in forest canopies. The use of selected genotypes in combination with silvicultural treatments that optimize site conditions in forest plantations provide both a challenge and an opportunity to study the biological and environmental determinants of forest growth. We investigated tree growth, crown development and leaf traits of two elite families of loblolly pine (Pinus taeda L.) and one family of slash pine (P. elliottii Mill.) at canopy closure. Two contrasting silvicultural treatments -- repeated fertilization and control of competing vegetation (MI treatment), and a single fertilization and control of competing vegetation treatment (C treatment) -- were applied at two experimental sites in the West Gulf Coastal Plain in Texas and Louisiana. At a common tree size (diameter at breast height), loblolly pine trees had longer and wider crowns, and at the plot-level, intercepted a greater fraction of photosynthetic photon flux than slash pine trees. Leaf-level, light-saturated assimilation rates (A(max)) and both mass- and area-based leaf nitrogen (N) decreased, and specific leaf area (SLA) increased with increasing canopy depth. Leaf-trait gradients were steeper in crowns of loblolly pine trees than of slash pine trees for SLA and leaf N, but not for A(max). There were no species differences in A(max), except in mass-based photosynthesis in upper crowns, but the effect of silvicultural treatment on A(max) differed between sites. Across all crown positions, A(max) was correlated with leaf N, but the relationship differed between sites and treatments. Observed patterns of variation in leaf properties within crowns reflected acclimation to developing light gradients in stands with closing canopies. Tree growth was not directly related to A(max), but there was a strong correlation between tree growth and plot-level light interception in both species. Growth efficiency was unaffected by silvicultural treatment. Thus, when coupled with leaf area and light interception at the crown and canopy levels, A(max) provides insight into family and silvicultural effects on tree growth.

Rainfall interception by tree crown and leaf litter: an interactive process

Treesearch

Xiang Li; Qingfu Xiao; Jianzhi Niu; Salli Dymond; E. Gregory McPherson; Natalie van Doorn; Xinxiao Yu; Baoyuan Xie; Kebin Zhang; Jiao Li

2017-01-01

Rainfall interception research in forest ecosystems usually focuses on interception by either tree crown or leaf litter, although the 2 components interact when rainfall occurs. A process-based study was conducted to jointly measure rainfall interception by crown and litter and the interaction between the 2 interception processes for 4 tree species (...

Estimating average tree crown size using spatial information from Ikonos and QuickBird images: Across-sensor and across-site comparisons

Treesearch

Conghe Song; Matthew B. Dickinson; Lihong Su; Su Zhang; Daniel Yaussey

2010-01-01

The forest canopy is the medium for energy, mass, and momentum exchanges between the forest ecosystem and the atmosphere. Tree crown size is a critical aspect of canopy structure that significantly influences these biophysical processes in the canopy. Tree crown size is also strongly related to other canopy structural parameters, such as tree height, diameter at breast...

The expression of light-related leaf functional traits depends on the location of individual leaves within the crown of isolated Olea europaea trees.

PubMed

Escribano-Rocafort, Adrián G; Ventre-Lespiaucq, Agustina B; Granado-Yela, Carlos; Rubio de Casas, Rafael; Delgado, Juan A; Balaguer, Luis

2016-04-01

The spatial arrangement and expression of foliar syndromes within tree crowns can reflect the coupling between crown form and function in a given environment. Isolated trees subjected to high irradiance and concomitant stress may adjust leaf phenotypes to cope with environmental gradients that are heterogeneous in space and time within the tree crown. The distinct expression of leaf phenotypes among crown positions could lead to complementary patterns in light interception at the crown scale. We quantified eight light-related leaf traits across 12 crown positions of ten isolated Olea europaea trees in the field. Specifically, we investigated whether the phenotypic expression of foliar traits differed among crown sectors and layers and five periods of the day from sunrise to sunset. We investigated the consequences in terms of the exposed area of the leaves at the tree scale during a single day. All traits differed among crown positions except the length-to-width ratio of the leaves. We found a strong complementarity in the patterns of the potential exposed area of the leaves among day periods as a result of a non-random distribution of leaf angles across the crown. Leaf exposure at the outer layer was below 60 % of the displayed surface, reaching maximum interception during morning periods. Daily interception increased towards the inner layer, achieving consecutive maximization from east to west positions within the crown, matching the sun's trajectory. The expression of leaf traits within isolated trees of O. europaea varies continuously through the crown in a gradient of leaf morphotypes and leaf angles depending on the exposure and location of individual leaves. The distribution of light-related traits within the crown and the complementarity in the potential exposure patterns of the leaves during the day challenges the assumption of low trait variability within individuals. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Crown-level tree species classification from AISA hyperspectral imagery using an innovative pixel-weighting approach

NASA Astrophysics Data System (ADS)

Liu, Haijian; Wu, Changshan

2018-06-01

Crown-level tree species classification is a challenging task due to the spectral similarity among different tree species. Shadow, underlying objects, and other materials within a crown may decrease the purity of extracted crown spectra and further reduce classification accuracy. To address this problem, an innovative pixel-weighting approach was developed for tree species classification at the crown level. The method utilized high density discrete LiDAR data for individual tree delineation and Airborne Imaging Spectrometer for Applications (AISA) hyperspectral imagery for pure crown-scale spectra extraction. Specifically, three steps were included: 1) individual tree identification using LiDAR data, 2) pixel-weighted representative crown spectra calculation using hyperspectral imagery, with which pixel-based illuminated-leaf fractions estimated using a linear spectral mixture analysis (LSMA) were employed as weighted factors, and 3) representative spectra based tree species classification was performed through applying a support vector machine (SVM) approach. Analysis of results suggests that the developed pixel-weighting approach (OA = 82.12%, Kc = 0.74) performed better than treetop-based (OA = 70.86%, Kc = 0.58) and pixel-majority methods (OA = 72.26, Kc = 0.62) in terms of classification accuracy. McNemar tests indicated the differences in accuracy between pixel-weighting and treetop-based approaches as well as that between pixel-weighting and pixel-majority approaches were statistically significant.

Crown Health of Reserve Hardwood Trees Following Reproduction Cutting in the Ouachita Mountains

Treesearch

Dale A. Starkey; James M. Guldin

2004-01-01

Abstract - Monitoring the health of reserve hardwood trees is being performed as part of the Ecosystem Management Research Project on the Ouachita and Ozark National Forests in Arkansas. A suite of crown variables (diameter, live crown ratio, density, dieback, and foliage transparency) was used to detect significant changes in reserve tree health...

Independent effects and interactions of stand diameter, tree diameter, crown class, and age on tree growth in mixed-species, even-aged hardwood stands

Treesearch

D.A. Marquis

1991-01-01

Many studies have shown that initial tree diameter is closely correlated with subsequent tree growth. But initial tree diameter is actually a confounded variable, incorporating both competitive position (crown class) and age.

Development of post-fire crown damage mortality thresholds in ponderosa pine

Treesearch

James F. Fowler; Carolyn Hull Sieg; Joel McMillin; Kurt K. Allen; Jose F. Negron; Linda L. Wadleigh; John A. Anhold; Ken E. Gibson

2010-01-01

Previous research has shown that crown scorch volume and crown consumption volume are the major predictors of post-fire mortality in ponderosa pine. In this study, we use piecewise logistic regression models of crown scorch data from 6633 trees in five wildfires from the Intermountain West to locate a mortality threshold at 88% scorch by volume for trees with no crown...

Crown-rise and crown-length dynamics: applications to loblolly pine

Treesearch

Harry T. Valentine; Ralph L. Amateis; Jeffrey H. Gove; Annikki Makela

2013-01-01

The original crown-rise model estimates the average height of a crown-base in an even-aged mono-species stand of trees. We have elaborated this model to reduce bias and prediction error, and to also provide crown-base estimates for individual trees. Results for the latter agree with a theory of branch death based on resource availability and allocation.We use the...

Evaluation of sampling strategies to estimate crown biomass

Treesearch

Krishna P Poudel; Hailemariam Temesgen; Andrew N Gray

2015-01-01

Depending on tree and site characteristics crown biomass accounts for a significant portion of the total aboveground biomass in the tree. Crown biomass estimation is useful for different purposes including evaluating the economic feasibility of crown utilization for energy production or forest products, fuel load assessments and fire management strategies, and wildfire...

Maintenance of Eastern hemlock forests: Factors associated with hemlock vulnerability to hemlock woolly adelgid

USGS Publications Warehouse

Fajvan, Mary Ann; Wood, Petra Bohall

2010-01-01

Eastern hemlock (Tsuga canadensis [L.]) is the most shade-tolerant and long-lived tree species in eastern North America. The hemlock woolly adelgid (Adelges tsugae) (HWA), is a nonnative invasive insect that feeds on eastern hemlock and Carolina hemlock (Tsuga caroliniana Engelm.). HWA currently is established in 17 eastern states and is causing tree decline and wide-ranging tree mortality. Our data from West Virginia and Pennsylvania suggest that hemlock crown vigor (a ranking of amount of live crown) relates to a predictable pattern of hemlock vulnerability at light and moderate levels of HWA infestation. We found that crown variables, such as live crown ratio and crown density and transparency, are accurate predictors of hemlock decline; more vigorous trees appear to be less vulnerable to HWA. Thus, silvicultural thinning treatments may be a means for reducing stand densities and increasing crown vigor in colder areas where climate may slow HWA spread.

Markov-random-field-based super-resolution mapping for identification of urban trees in VHR images

NASA Astrophysics Data System (ADS)

Ardila, Juan P.; Tolpekin, Valentyn A.; Bijker, Wietske; Stein, Alfred

2011-11-01

Identification of tree crowns from remote sensing requires detailed spectral information and submeter spatial resolution imagery. Traditional pixel-based classification techniques do not fully exploit the spatial and spectral characteristics of remote sensing datasets. We propose a contextual and probabilistic method for detection of tree crowns in urban areas using a Markov random field based super resolution mapping (SRM) approach in very high resolution images. Our method defines an objective energy function in terms of the conditional probabilities of panchromatic and multispectral images and it locally optimizes the labeling of tree crown pixels. Energy and model parameter values are estimated from multiple implementations of SRM in tuning areas and the method is applied in QuickBird images to produce a 0.6 m tree crown map in a city of The Netherlands. The SRM output shows an identification rate of 66% and commission and omission errors in small trees and shrub areas. The method outperforms tree crown identification results obtained with maximum likelihood, support vector machines and SRM at nominal resolution (2.4 m) approaches.

Common allometric response of open-grown leader shoots to tree height in co-occurring deciduous broadleaved trees

PubMed Central

Miyata, Rie; Kubo, Takuya; Nabeshima, Eri; Kohyama, Takashi S.

2011-01-01

Background and Aims Morphology of crown shoots changes with tree height. The height of forest trees is usually correlated with the light environment and this makes it difficult to separate the effects of tree size and of light conditions on the morphological plasticity of crown shoots. This paper addresses the tree-height dependence of shoot traits under full-light conditions where a tree crown is not shaded by other crowns. Methods Focus is given to relationships between tree height and top-shoot traits, which include the shoot's leaf-blades and non-leafy mass, its total leaf-blade area and the length and basal diameter of the shoot's stem. We examine the allometric characteristics of open-grown current-year leader shoots at the tops of forest tree crowns up to 24 m high and quantify their responses to tree height in 13 co-occurring deciduous hardwood species in a cool-temperate forest in northern Japan. Key Results Dry mass allocated to leaf blades in a leader shoot increased with tree height in all 13 species. Specific leaf area decreased with tree height. Stem basal area was almost proportional to total leaf area in a leader shoot, where the proportionality constant did not depend on tree height, irrespective of species. Stem length for a given stem diameter decreased with tree height. Conclusions In the 13 species observed, height-dependent changes in allometry of leader shoots were convergent. This finding suggests that there is a common functional constraint in tree-height development. Under full-light conditions, leader shoots of tall trees naturally experience more severe water stress than those of short trees. We hypothesize that the height dependence of shoot allometry detected reflects an integrated response to height-associated water stress, which contributes to successful crown expansion and height gain. PMID:21914698

A comparison of tree crown condition in areas with and without gypsy moth activity

Treesearch

KaDonna C. Randolph

2005-01-01

This study compared the crown condition of trees within and outside areas of gypsy moth defoliation in Virginia via hypothesis tests of mean differences for five U.S. Department of Agriculture (USDA) Forest Service Forest Inventory and Analysis phase 3 crown condition indicators. Significant differences were found between the trees located within and outside gypsy moth...

A comparison of tree crown condition in areas with and without gypsy moth activity

Treesearch

KaDonna C. Randolph

2007-01-01

This study compared the crown condition of trees within and outside areas of gypsy moth defoliation in Virginia via hypothesis tests of mean differences for five U.S. Department of Agriculture (USDA) Forest Service Forest Inventory and Analysis phase 3 crown condition indicators. Significant differences were found between the trees located within and outside gypsy moth...

Preformation in vegetative buds of pistachio (Pistacia vera): relationship to shoot morphology, crown structure and rootstock vigor.

PubMed

Spann, Timothy M; Beede, Robert H; Dejong, Theodore M

2007-08-01

Effects of rootstock, shoot carbohydrate status, crop load and crown position on the number of preformed leaf primordia in the dormant terminal and lateral buds of mature and immature 'Kerman' pistachio (Pistacia vera L.) trees were investigated to determine if rootstock vigor is associated with greater shoot preformation. There was no significant variation in preformation related to the factors studied, suggesting strong genetic control of preformation in 'Kerman' pistachio. The growth differences observed among trees on different rootstocks were associated with greater stimulation of neoformed growth in trees on the more vigorous rootstocks. However, most annual extension growth in mature tree crowns was preformed, contrasting with the relatively high rate of neoformation found in young tree crowns. Large amounts of neoformed growth in young trees may allow the trees to become established quickly and secure resources, whereas predominantly preformed growth in mature trees may allow for continued crown expansion without outgrowing available resources. We hypothesized that the stimulation of neoformed growth by the more vigorous rootstocks is associated with greater resource uptake or transport, or both. Understanding the source of variation in shoot extension growth on different rootstocks has important implications for orchard management practices.

Towards an Optimized Method of Olive Tree Crown Volume Measurement

PubMed Central

Miranda-Fuentes, Antonio; Llorens, Jordi; Gamarra-Diezma, Juan L.; Gil-Ribes, Jesús A.; Gil, Emilio

2015-01-01

Accurate crown characterization of large isolated olive trees is vital for adjusting spray doses in three-dimensional crop agriculture. Among the many methodologies available, laser sensors have proved to be the most reliable and accurate. However, their operation is time consuming and requires specialist knowledge and so a simpler crown characterization method is required. To this end, three methods were evaluated and compared with LiDAR measurements to determine their accuracy: Vertical Crown Projected Area method (VCPA), Ellipsoid Volume method (VE) and Tree Silhouette Volume method (VTS). Trials were performed in three different kinds of olive tree plantations: intensive, adapted one-trunked traditional and traditional. In total, 55 trees were characterized. Results show that all three methods are appropriate to estimate the crown volume, reaching high coefficients of determination: R2 = 0.783, 0.843 and 0.824 for VCPA, VE and VTS, respectively. However, discrepancies arise when evaluating tree plantations separately, especially for traditional trees. Here, correlations between LiDAR volume and other parameters showed that the Mean Vector calculated for VCPA method showed the highest correlation for traditional trees, thus its use in traditional plantations is highly recommended. PMID:25658396

Automatic tree parameter extraction by a Mobile LiDAR System in an urban context.

PubMed

Herrero-Huerta, Mónica; Lindenbergh, Roderik; Rodríguez-Gonzálvez, Pablo

2018-01-01

In an urban context, tree data are used in city planning, in locating hazardous trees and in environmental monitoring. This study focuses on developing an innovative methodology to automatically estimate the most relevant individual structural parameters of urban trees sampled by a Mobile LiDAR System at city level. These parameters include the Diameter at Breast Height (DBH), which was estimated by circle fitting of the points belonging to different height bins using RANSAC. In the case of non-circular trees, DBH is calculated by the maximum distance between extreme points. Tree sizes were extracted through a connectivity analysis. Crown Base Height, defined as the length until the bottom of the live crown, was calculated by voxelization techniques. For estimating Canopy Volume, procedures of mesh generation and α-shape methods were implemented. Also, tree location coordinates were obtained by means of Principal Component Analysis. The workflow has been validated on 29 trees of different species sampling a stretch of road 750 m long in Delft (The Netherlands) and tested on a larger dataset containing 58 individual trees. The validation was done against field measurements. DBH parameter had a correlation R2 value of 0.92 for the height bin of 20 cm which provided the best results. Moreover, the influence of the number of points used for DBH estimation, considering different height bins, was investigated. The assessment of the other inventory parameters yield correlation coefficients higher than 0.91. The quality of the results confirms the feasibility of the proposed methodology, providing scalability to a comprehensive analysis of urban trees.

Automatic tree parameter extraction by a Mobile LiDAR System in an urban context

PubMed Central

Lindenbergh, Roderik; Rodríguez-Gonzálvez, Pablo

2018-01-01

In an urban context, tree data are used in city planning, in locating hazardous trees and in environmental monitoring. This study focuses on developing an innovative methodology to automatically estimate the most relevant individual structural parameters of urban trees sampled by a Mobile LiDAR System at city level. These parameters include the Diameter at Breast Height (DBH), which was estimated by circle fitting of the points belonging to different height bins using RANSAC. In the case of non-circular trees, DBH is calculated by the maximum distance between extreme points. Tree sizes were extracted through a connectivity analysis. Crown Base Height, defined as the length until the bottom of the live crown, was calculated by voxelization techniques. For estimating Canopy Volume, procedures of mesh generation and α-shape methods were implemented. Also, tree location coordinates were obtained by means of Principal Component Analysis. The workflow has been validated on 29 trees of different species sampling a stretch of road 750 m long in Delft (The Netherlands) and tested on a larger dataset containing 58 individual trees. The validation was done against field measurements. DBH parameter had a correlation R2 value of 0.92 for the height bin of 20 cm which provided the best results. Moreover, the influence of the number of points used for DBH estimation, considering different height bins, was investigated. The assessment of the other inventory parameters yield correlation coefficients higher than 0.91. The quality of the results confirms the feasibility of the proposed methodology, providing scalability to a comprehensive analysis of urban trees. PMID:29689076

Effects of crown release on growth and quality of even-aged red maple stands

Treesearch

Terry F. Strong; Audra E. Hubbell; Adam H. Weise; Gayne G. Erdmann

2006-01-01

The effects of six crown-release treatments on growth and bole quality of 54 dominant, codominant, and intermediate red maples (Acer rubrum L.) were examined in an even-aged stand in upper Michigan. Treatments included an unreleased control, a single-tree and a two-tree crown release, and a full crown-to-crown release of 5, 10, and 15ft. Twenty-two...

Using crown condition variables as indicators of forest health

Treesearch

Stanley J. Zarnoch; William A. Bechtold; K.W. Stolte

2004-01-01

Indicators of forest health used in previous studies have focused on crown variables analyzed individually at the tree level by summarizing over all species. This approach has the virtue of simplicity but does not account for the three-dimensional attributes of a tree crown, the multivariate nature of the crown variables, or variability among species. To alleviate...

Digital photo monitoring for tree crown

Treesearch

Neil Clark; Sang-Mook Lee

2007-01-01

Assessing change in the amount of foliage within a tree’s crown is the goal of crown transparency estimation, a component in many forest health assessment programs. Many sources of variability limit analysis and interpretation of crown condition data. Increased precision is needed to detect more subtle changes that are important for detection of health problems....

Digital photography for urban street tree crown conditions

Treesearch

Neil A. Clark; Sang-Mook Lee; William A. Bechtold; Gregory A. Reams

2006-01-01

Crown variables such as height, diameter, live crown ratio, dieback, transparency, and density are all collected as part of the overall crown assessment (USDA 2004). Transparency and density are related to the amount of foliage and thus the photosynthetic potential of the tree. These measurements are both currently based on visual estimates and have been shown to be...

Synergistic interactions between leaf beetle herbivory and fire enhance tamarisk (Tamarix spp.) mortality

USGS Publications Warehouse

Drus, Gail M.; Dudley, Tom L.; Antonio, Carla M.; Even, Thomas J.; Brooks, Matt L.; Matchett, J.R.

2014-01-01

The combined effects of herbivory and fire on plant mortality were investigated using prescribed burns of tamarisk (Tamarix ramosissima Lebed) exposed to herbivory by the saltcedar leaf beetle (Chrysomelidae: Diorhabda carinulata Desbrocher). Tamarix stands in the Humboldt Sink (NV, USA) were divided into three treatments: summer burn (August 2006), fall burn (October 2006) and control (unburned), and litter depth was manipulated to vary fire intensity within burn seasons. A gradient of existing herbivory impact was described with three plant condition metrics prior to fire: reduced proportions of green canopy, percent root crown starch sampled at the height of the growing season (August 2006), and percent root crown starch measured during dormancy (December 2006). August root crown starch concentration and proportion green canopy were strongly correlated, although the proportion green canopy predicted mortality better than August root crown starch. December root crown starch concentration was more depleted in unburned trees and in trees burned during the summer than in fall burn trees. Mortality in summer burned trees was higher than fall burned trees due to higher fire intensity, but December root crown starch available for resprouting in the spring was also lower in summer burned trees. The greatest mortality was observed in trees with the lowest December root crown starch concentration which were exposed to high fire intensity. Disproportionate changes in the slope and curvature of prediction traces as fire intensity and December starch reach reciprocal maximum and minimum levels indicate that beetle herbivory and fire intensity are synergistic.

Vertical stratification of the nutritional value of fruit: macronutrients and condensed tannins.

PubMed

Houle, Alain; Conklin-Brittain, Nancy L; Wrangham, Richard W

2014-12-01

Competing successfully for the best feeding sites is an important behavioral strategy but little is known about how feeding sites vary nutritionally within a fruit tree. To answer this question we tested how the nutritional value of a fruit is influenced by its ripeness and its height within the tree crown. A complementary objective was to assess the nutritional value of the midripe fruit, a food item rarely mentioned in the literature despite being exploited on a daily basis by many frugivores. We measured how the dry weight of pulp, water content, and concentration of macronutrients and condensed tannins varied within the tree crowns of 15 fruit species. Collections occurred early in the fruiting cycle, so as to assess the amount of food in the tree before its exploitation by primates. We found that (1) the upper crown produced fruit densities 4.2 times higher, and a fruit crop 4.8 times larger, than the lower crown of the same tree; (2) considering only midripe and ripe stages, upper-crown fruits contained 28.6% more dry pulp, 21.1% more water, and 13.5% more sugars per dry matter than lower-crown fruits of the same tree; (3) midripe fruits contained 80% of the concentrations of sugars of ripe fruits, making them a sweeter food item than one would expect from the intermediate color of their epidermis; (4) cellulose, hemicellulose, proteins, and ash proportionally decreased in concentration while dry pulp and sugars increased during ripening; and (5) ripe fruits were usually rare in the tree (<0.5% of all fruit available) compared to midripe fruits (3-8%). Overall, upper-crown feeding sites produced a higher density and quality of food than lower-crown sites of the same tree. Our data therefore provide a clear nutritional explanation for why tree-feeding frugivores compete for the highest feeding sites. © 2014 Wiley Periodicals, Inc.

Automated estimation of individual conifer tree height and crown diameter via Two-dimensional spatial wavelet analysis of lidar data

Treesearch

Michael J. Falkowski; Alistair M.S. Smith; Andrew T. Hudak; Paul E. Gessler; Lee A. Vierling; Nicholas L. Crookston

2006-01-01

We describe and evaluate a new analysis technique, spatial wavelet analysis (SWA), to automatically estimate the location, height, and crown diameter of individual trees within mixed conifer open canopy stands from light detection and ranging (lidar) data. Two-dimensional Mexican hat wavelets, over a range of likely tree crown diameters, were convolved with lidar...

Crown-Diameter Prediction Models for 87 Species of Stand-Grown Trees in the Eastern United States

Treesearch

William A. Bechtold

2003-01-01

The mean crown diameters of stand-grown trees were modeled as a function of stem diameter, live-crown ratio, stand basal area, latitude, longitude, elevation, and Hopkins bioclimatic index for 87 tree species in the eastern United States. Stem diameter was statistically significant in all models, and a quadratic term for stem diameter was required for some species....

Urban Crowns: crown analysis software to assist in quantifying urban tree benefits

Treesearch

Matthew F. Winn; Sang-Mook Lee Bradley; Philip A. Araman

2010-01-01

UrbanCrowns is a Microsoft® Windows®-based computer program developed by the U.S. Forest Service Southern Research Station. The software assists urban forestry professionals, arborists, and community volunteers in assessing and monitoring the crown characteristics of urban trees (both deciduous and coniferous) using a single side-view digital photograph. Program output...

Spatial and temporal distribution of trunk-injected imidacloprid in apple tree canopies.

PubMed

Aćimović, Srđan G; VanWoerkom, Anthony H; Reeb, Pablo D; Vandervoort, Christine; Garavaglia, Thomas; Cregg, Bert M; Wise, John C

2014-11-01

Pesticide use in orchards creates drift-driven pesticide losses which contaminate the environment. Trunk injection of pesticides as a target-precise delivery system could greatly reduce pesticide losses. However, pesticide efficiency after trunk injection is associated with the underinvestigated spatial and temporal distribution of the pesticide within the tree crown. This study quantified the spatial and temporal distribution of trunk-injected imidacloprid within apple crowns after trunk injection using one, two, four or eight injection ports per tree. The spatial uniformity of imidacloprid distribution in apple crowns significantly increased with more injection ports. Four ports allowed uniform spatial distribution of imidacloprid in the crown. Uniform and non-uniform spatial distributions were established early and lasted throughout the experiment. The temporal distribution of imidacloprid was significantly non-uniform. Upper and lower crown positions did not significantly differ in compound concentration. Crown concentration patterns indicated that imidacloprid transport in the trunk occurred through radial diffusion and vertical uptake with a spiral pattern. By showing where and when a trunk-injected compound is distributed in the apple tree canopy, this study addresses a key knowledge gap in terms of explaining the efficiency of the compound in the crown. These findings allow the improvement of target-precise pesticide delivery for more sustainable tree-based agriculture. © 2014 Society of Chemical Industry.

Vertical stratification of the foliar fungal community in the world's tallest trees.

PubMed

Harrison, Joshua G; Forister, Matthew L; Parchman, Thomas L; Koch, George W

2016-12-01

The aboveground tissues of plants host numerous, ecologically important fungi, yet patterns in the spatial distribution of these fungi remain little known. Forest canopies in particular are vast reservoirs of fungal diversity, but intracrown variation in fungal communities has rarely been explored. Knowledge of how fungi are distributed throughout tree crowns will contribute to our understanding of interactions between fungi and their host trees and is a first step toward investigating drivers of community assembly for plant-associated fungi. Here we describe spatial patterns in fungal diversity within crowns of the world's tallest trees, coast redwoods (Sequoia sempervirens). We took a culture-independent approach, using the Illumina MiSeq platform, to characterize the fungal assemblage at multiple heights within the crown across the geographical range of the coast redwood. Within each tree surveyed, we uncovered evidence for vertical stratification in the fungal community; different portions of the tree crown harbored different assemblages of fungi. We also report between-tree variation in the fungal community within redwoods. Our results suggest the potential for vertical stratification of fungal communities in the crowns of other tall tree species and should prompt future study of the factors giving rise to this stratification. © 2016 Botanical Society of America.

Rainforest air-conditioning: the moderating influence of epiphytes on the microclimate in tropical tree crowns

NASA Astrophysics Data System (ADS)

Stuntz, Sabine; Simon, Ulrich; Zotz, Gerhard

2002-05-01

Epiphytes are often assumed to influence the microclimatic conditions of the tree crowns that they inhabit. In order to quantify this notion, we measured the parameters "temperature" (of the substrate surface and the boundary layer of air above it), "evaporative drying rate" and "evapotranspiration" at various locations within tree crowns with differing epiphyte assemblages. The host tree species was Annona glabra, which was either populated by one of three epiphyte species ( Dimerandra emarginata, Tillandsia fasciculata, or Vriesea sanguinolenta) or was epiphyte-free. We found that during the hottest and driest time of day, microsites in the immediate proximity of epiphytes had significantly lower temperatures than epiphyte-bare locations within the same tree crown, even though the latter were also shaded by host tree foliage or branches. Moreover, water loss through evaporative drying at microsites adjacent to epiphytes was almost 20% lower than at exposed microsites. We also found that, over the course of several weeks, the evapotranspiration in tree crowns bearing epiphytes was significantly lower than in trees without epiphytes. Although the influence of epiphytes on temperature extremes and evaporation rates is relatively subtle, their mitigating effect could be of importance for small animals like arthropods inhabiting an environment as harsh and extreme as the tropical forest canopy.

Applicability of non-destructive substitutes for leaf area in different stands of Norway spruce (Picea abies L. Karst.) focusing on traditional forest crown measures.

PubMed

Laubhann, Daniel; Eckmüllner, Otto; Sterba, Hubert

2010-09-30

Since individual tree leaf area is an important measure for productivity as well as for site occupancy, it is of high interest in many studies about forest growth. The exact determination of leaf area is nearly impossible. Thus, a common way to get information about leaf area is to use substitutes. These substitutes are often variables which are collected in a destructive way which is not feasible for long term studies. Therefore, this study aimed at testing the applicability of using substitutes for leaf area which could be collected in a non-destructive way, namely crown surface area and crown projection area. In 8 stands of Norway spruce (Picea abies L. Karst.), divided into three age classes and two thinning treatments, a total of 156 trees were felled in order to test the relationship between leaf area and crown surface area and crown projection area, respectively. Individual tree leaf area of the felled sample trees was estimated by 3P-branch sampling with an accuracy of ±10%. Crown projection area and crown surface area were compared with other, more commonly used, but destructive predictors of leaf area, namely sapwood area at different heights on the bole. Our investigations confirmed findings of several studies that sapwood area is the most precise measure for leaf area because of the high correlation between sapwood area and the leaf area. But behind sapwood area at crown base and sapwood area at three tenth of the tree height the predictive ability of crown surface area was ranked third and even better than that of sapwood area at breast height (R(2) = 0.656 compared with 0.600). Within the stands leaf area is proportional to crown surface area. Using the pooled data of all stands a mixed model approach showed that additionally to crown surface area dominant height and diameter at breast height (dbh) improved the leaf area estimates. Thus, taking dominant height and dbh into account, crown surface area can be recommended for estimating the leaf area of individual trees. The resulting model was in line with many other findings on the leaf area and leaf mass relationships with crown size. From the additional influence of dominant height and dbh in the leaf area model we conclude that the used crown model could be improved by estimating the position of the maximum crown width and the crown width at the base of the crown depending on these two variables.

Applicability of non-destructive substitutes for leaf area in different stands of Norway spruce (Picea abies L. Karst.) focusing on traditional forest crown measures

PubMed Central

Laubhann, Daniel; Eckmüllner, Otto; Sterba, Hubert

2010-01-01

Since individual tree leaf area is an important measure for productivity as well as for site occupancy, it is of high interest in many studies about forest growth. The exact determination of leaf area is nearly impossible. Thus, a common way to get information about leaf area is to use substitutes. These substitutes are often variables which are collected in a destructive way which is not feasible for long term studies. Therefore, this study aimed at testing the applicability of using substitutes for leaf area which could be collected in a non-destructive way, namely crown surface area and crown projection area. In 8 stands of Norway spruce (Picea abies L. Karst.), divided into three age classes and two thinning treatments, a total of 156 trees were felled in order to test the relationship between leaf area and crown surface area and crown projection area, respectively. Individual tree leaf area of the felled sample trees was estimated by 3P-branch sampling with an accuracy of ±10%. Crown projection area and crown surface area were compared with other, more commonly used, but destructive predictors of leaf area, namely sapwood area at different heights on the bole. Our investigations confirmed findings of several studies that sapwood area is the most precise measure for leaf area because of the high correlation between sapwood area and the leaf area. But behind sapwood area at crown base and sapwood area at three tenth of the tree height the predictive ability of crown surface area was ranked third and even better than that of sapwood area at breast height (R2 = 0.656 compared with 0.600). Within the stands leaf area is proportional to crown surface area. Using the pooled data of all stands a mixed model approach showed that additionally to crown surface area dominant height and diameter at breast height (dbh) improved the leaf area estimates. Thus, taking dominant height and dbh into account, crown surface area can be recommended for estimating the leaf area of individual trees. The resulting model was in line with many other findings on the leaf area and leaf mass relationships with crown size. From the additional influence of dominant height and dbh in the leaf area model we conclude that the used crown model could be improved by estimating the position of the maximum crown width and the crown width at the base of the crown depending on these two variables. PMID:21072126

Simulated western spruce budworm defoliation reduces torching and crowning potential: A sensitivity analysis using a physics-based fire model

Treesearch

Gregory M. Cohn; Russell A. Parsons; Emily K. Heyerdahl; Daniel G. Gavin; Aquila Flower

2014-01-01

The widespread, native defoliator western spruce budworm (Choristoneura occidentalis Freeman) reduces canopy fuels, which might affect the potential for surface fires to torch (ignite the crowns of individual trees) or crown (spread between tree crowns). However, the effects of defoliation on fire behaviour are poorly understood. We used a physics-based fire model to...

Modeling individual trees in an urban environment using dense discrete return LIDAR

NASA Astrophysics Data System (ADS)

Bandyopadhyay, Madhurima; van Aardt, Jan A. N.; van Leeuwen, Martin

2015-05-01

The urban forest is becoming increasingly important in the contexts of urban green space, carbon sequestration and offsets, and socio-economic impacts. This has led to a recent increase in attention being paid to urban environmental management. Tree biomass, specifically, is a vital indicator of carbon storage and has a direct impact on urban forest health and carbon sequestration. As an alternative to expensive and time-consuming field surveys, remote sensing has been used extensively in measuring dynamics of vegetation and estimating biomass. Light detection and ranging (LiDAR) has proven especially useful to characterize the three dimensional (3D) structure of forests. In urban contexts however, information is frequently required at the individual tree level, necessitating the proper delineation of tree crowns. Yet, crown delineation is challenging for urban trees where a wide range of stress factors and cultural influences affect growth. In this paper high resolution LiDAR data were used to infer biomass based on individual tree attributes. A multi-tiered delineation algorithm was designed to extract individual tree-crowns. At first, dominant tree segments were obtained by applying watershed segmentation on the crown height model (CHM). Next, prominent tree top positions within each segment were identified via a regional maximum transformation and the crown boundary was estimated for each of the tree tops. Finally, undetected trees were identified using a best-fitting circle approach. After tree delineation, individual tree attributes were used to estimate tree biomass and the results were validated with associated field mensuration data. Results indicate that the overall tree detection accuracy is nearly 80%, and the estimated biomass model has an adjusted-R2 of 0.5.

Surface storage of rainfall in tree crowns: not all trees are equal

Treesearch

E. Gregory McPherson; Q. Xiao; Natalie van Doorn; P. Peper; E. Teach

2017-01-01

Urban forests can be an effective strategy for managing stormwater. The soil that supports tree growth acts like a reservoir that reduces runoff. The tree crown intercepts rainfall on leaves and stems and its evaporation reduces water reaching the ground below. Until now surface storage capacities have been studied only for forest trees. Based on forest research, green...

Forest Health Monitoring in Massachusetts, 1996-1999

Treesearch

Northeastern Research Station

2002-01-01

Massachusetts has mature forests dominated by hardwood species. Most of the trees are healthy, with full crowns (low transparency, high density), little dieback and little damage. Red maple trees made up almost one quarter of the trees and had slightly higher amounts of dieback, thinner crowns, and more damage than other common tree species.

Mortality Risks for Forest Trees Threatened with Gypsy Moth Infestation

Treesearch

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

1987-01-01

Presents guidelines for estimating potential tree mortality associated with gypsy moth defoliation. A tree's crown condition, crown position, and species group can be used to assign probabilities of death. Forest-land managers need such information to develop marking guides and implement silvicultural treatments for forest trees threatened with gypsy moth...

Extracting forest canopy structure from spatial information of high resolution optical imagery: tree crown size versus leaf area index

Treesearch

C. Song; M.B. Dickinson

2008-01-01

Leaves are the primary interface where energy, water and carbon exchanges occur between the forest ecosystems and the atmosphere. Leaf area index (LAI) is a measure of the amount of leaf area in a stand, and the tree crown size characterizes how leaves are clumped in the canopy. Both LAI and tree crown size are of essential ecological and management value. There is a...

Process-based rainfall interception by small trees in Northern China: The effect of rainfall traits and crown structure characteristics

Treesearch

Xiang Li; Qingfu Xiao; Jianzhi Niu; Salli Dymond; Natalie S. van Doorn; Xinxiao Yu; Baoyuan Xie; Xizhi Lv; Kebin Zhang; Jiao Li

2016-01-01

Rainfall interception by a tree's crown is one of the most important hydrological processes in an ecosystem, yet the mechanisms of interception are not well understood. A process-based experiment was conducted under five simulated rainfall intensities (from 10 to 150 mm h−1) to directly quantify tree crown interception and examine the effect...

the Role of Species, Structure, and Biochemical Traits in the Spatial Distribution of a Woodland Community

NASA Astrophysics Data System (ADS)

Adeline, K.; Ustin, S.; Roth, K. L.; Huesca Martinez, M.; Schaaf, C.; Baldocchi, D. D.; Gastellu-Etchegorry, J. P.

2015-12-01

The assessment of canopy biochemical diversity is critical for monitoring ecological and physiological functioning and for mapping vegetation change dynamics in relation to environmental resources. For example in oak woodland savannas, these dynamics are mainly driven by water constraints. Inversion using radiative transfer theory is one method for estimating canopy biochemistry. However, this approach generally only considers relatively simple scenarios to model the canopy due to the difficulty in encompassing stand heterogeneity with spatial and temporal consistency. In this research, we compared 3 modeling strategies for estimating canopy biochemistry variables (i.e. chlorophyll, carotenoids, water, dry matter) by coupling of the PROSPECT (leaf level) and DART (canopy level) models : i) a simple forest representation made of ellipsoid trees, and two representations taking into account the tree species and structural composition, and the landscape spatial pattern, using (ii) geometric tree crown shapes and iii) detailed tree crown and wood structure retrieved from terrestrial lidar acquisitions. AVIRIS 18m remote sensing data are up-scaled to simulate HyspIRI 30m images. Both spatial resolutions are validated by measurements acquired during 2013-2014 field campaigns (cover/tree inventory, LAI, leaf sampling, optical measures). The results outline the trade-off between accurate and abstract canopy modeling for inversion purposes and may provide perspectives to assess the impact of the California drought with multi-temporal monitoring of canopy biochemistry traits.

The influence of prefire tree growth and crown condition on postfire mortality of sugar pine following prescribed fire in Sequoia National Park

USGS Publications Warehouse

Nesmith, Jonathan C. B.; Das, Adrian J.; O'Hara, Kevin L.; van Mantgem, Phillip J.

2015-01-01

Tree mortality is a vital component of forest management in the context of prescribed fires; however, few studies have examined the effect of prefire tree health on postfire mortality. This is especially relevant for sugar pine (Pinus lambertiana Douglas), a species experiencing population declines due to a suite of anthropogenic factors. Using data from an old-growth mixed-conifer forest in Sequoia National Park, we evaluated the effects of fire, tree size, prefire radial growth, and crown condition on postfire mortality. Models based only on tree size and measures of fire damage were compared with models that included tree size, fire damage, and prefire tree health (e.g., measures of prefire tree radial growth or crown condition). Immediately following the fire, the inclusion of different metrics of prefire tree health produced variable improvements over the models that included only tree size and measures of fire damage, as models that included measures of crown condition performed better than fire-only models, but models that included measures of prefire radial growth did not perform better. However, 5 years following the fire, sugar pine mortality was best predicted by models that included measures of both fire damage and prefire tree health, specifically, diameter at breast height (DBH, 1.37 m), crown scorch, 30-year mean growth, and the number of sharp declines in growth over a 30-year period. This suggests that factors that influence prefire tree health (e.g., drought, competition, pathogens, etc.) may partially determine postfire mortality, especially when accounting for delayed mortality following fire.

Monitoring individual tree-based change with airborne lidar.

PubMed

Duncanson, Laura; Dubayah, Ralph

2018-05-01

Understanding the carbon flux of forests is critical for constraining the global carbon cycle and managing forests to mitigate climate change. Monitoring forest growth and mortality rates is critical to this effort, but has been limited in the past, with estimates relying primarily on field surveys. Advances in remote sensing enable the potential to monitor tree growth and mortality across landscapes. This work presents an approach to measure tree growth and loss using multidate lidar campaigns in a high-biomass forest in California, USA. Individual tree crowns were delineated in 2008 and again in 2013 using a 3D crown segmentation algorithm, with derived heights and crown radii extracted and used to estimate individual tree aboveground biomass. Tree growth, loss, and aboveground biomass were analyzed with respect to tree height and crown radius. Both tree growth and loss rates decrease with increasing tree height, following the expectation that trees slow in growth rate as they age. Additionally, our aboveground biomass analysis suggests that, while the system is a net source of aboveground carbon, these carbon dynamics are governed by size class with the largest sources coming from the loss of a relatively small number of large individuals. This study demonstrates that monitoring individual tree-based growth and loss can be conducted with multidate airborne lidar, but these methods remain relatively immature. Disparities between lidar acquisitions were particularly difficult to overcome and decreased the sample of trees analyzed for growth rate in this study to 21% of the full number of delineated crowns. However, this study illuminates the potential of airborne remote sensing for ecologically meaningful forest monitoring at an individual tree level. As methods continue to improve, airborne multidate lidar will enable a richer understanding of the drivers of tree growth, loss, and aboveground carbon flux.

A dynamic processes study of PM retention by trees under different wind conditions.

PubMed

Xie, Changkun; Kan, Liyan; Guo, Jiankang; Jin, Sijia; Li, Zhigang; Chen, Dan; Li, Xin; Che, Shengquan

2018-02-01

Particulate matter (PM) is one of the most serious environmental problems, exacerbating respiratory and vascular illnesses. Plants have the ability to reduce non-point source PM pollution through retention on leaves and branches. Studies of the dynamic processes of PM retention by plants and the mechanisms influencing this process will help to improve the efficiency of urban greening for PM reduction. We examined dynamic processes of PM retention and the major factors influencing PM retention by six trees with different branch structure characteristics in wind tunnel experiments at three different wind speeds. The results showed that the changes of PM numbers retained by plant leaves over time were complex dynamic processes for which maximum values could exceed minimum values by over 10 times. The average value of PM measured in multiple periods and situations can be considered a reliable indicator of the ability of the plant to retain PM. The dynamic processes were similar for PM 10 and PM 2.5 . They could be clustered into three groups simulated by continually-rising, inverse U-shaped, and U-shaped polynomial functions, respectively. The processes were the synthetic effect of characteristics such as species, wind speed, period of exposure and their interactions. Continually-rising functions always explained PM retention in species with extremely complex branch structure. Inverse U-shaped processes explained PM retention in species with relatively simple branch structure and gentle wind. The U-shaped processes mainly explained PM retention at high wind speeds and in species with a relatively simple crown. These results indicate that using plants with complex crowns in urban greening and decreasing wind speed in plant communities increases the chance of continually-rising or inverse U-shaped relationships, which have a positive effect in reducing PM pollution. Copyright © 2017 Elsevier Ltd. All rights reserved.

Automatic extraction of tree crowns from aerial imagery in urban environment

NASA Astrophysics Data System (ADS)

Liu, Jiahang; Li, Deren; Qin, Xunwen; Yang, Jianfeng

2006-10-01

Traditionally, field-based investigation is the main method to investigate greenbelt in urban environment, which is costly and low updating frequency. In higher resolution image, the imagery structure and texture of tree canopy has great similarity in statistics despite the great difference in configurations of tree canopy, and their surface structures and textures of tree crown are very different from the other types. In this paper, we present an automatic method to detect tree crowns using high resolution image in urban environment without any apriori knowledge. Our method catches unique structure and texture of tree crown surface, use variance and mathematical expectation of defined image window to position the candidate canopy blocks coarsely, then analysis their inner structure and texture to refine these candidate blocks. The possible spans of all the feature parameters used in our method automatically generate from the small number of samples, and HOLE and its distribution as an important characteristics are introduced into refining processing. Also the isotropy of candidate image block and holes' distribution is integrated in our method. After introduction the theory of our method, aerial imageries were used ( with a resolution about 0.3m ) to test our method, and the results indicate that our method is an effective approach to automatically detect tree crown in urban environment.

Predictive equations for dimensions and leaf area of coastal Southern California street trees

Treesearch

P.J. Peper; E.G. McPherson; S.M. Mori

2001-01-01

Tree height, crown height, crown width, diameter at breast height (dbh), and leaf area were measured for 16 species of commonly planted street trees in the coastal southern California city of Santa Monica, USA. The randomly sampled trees were planted from 1 to 44 years ago. Using number of years after planting or dbh as explanatory variables, mean values of dbh, tree...

A novel transferable individual tree crown delineation model based on Fishing Net Dragging and boundary classification

NASA Astrophysics Data System (ADS)

Liu, Tao; Im, Jungho; Quackenbush, Lindi J.

2015-12-01

This study provides a novel approach to individual tree crown delineation (ITCD) using airborne Light Detection and Ranging (LiDAR) data in dense natural forests using two main steps: crown boundary refinement based on a proposed Fishing Net Dragging (FiND) method, and segment merging based on boundary classification. FiND starts with approximate tree crown boundaries derived using a traditional watershed method with Gaussian filtering and refines these boundaries using an algorithm that mimics how a fisherman drags a fishing net. Random forest machine learning is then used to classify boundary segments into two classes: boundaries between trees and boundaries between branches that belong to a single tree. Three groups of LiDAR-derived features-two from the pseudo waveform generated along with crown boundaries and one from a canopy height model (CHM)-were used in the classification. The proposed ITCD approach was tested using LiDAR data collected over a mountainous region in the Adirondack Park, NY, USA. Overall accuracy of boundary classification was 82.4%. Features derived from the CHM were generally more important in the classification than the features extracted from the pseudo waveform. A comprehensive accuracy assessment scheme for ITCD was also introduced by considering both area of crown overlap and crown centroids. Accuracy assessment using this new scheme shows the proposed ITCD achieved 74% and 78% as overall accuracy, respectively, for deciduous and mixed forest.

Effect of irrigation on needle morphology, shoot and stem growth in a drought-exposed Pinus sylvestris forest.

PubMed

Dobbertin, Matthias; Eilmann, Britta; Bleuler, Peter; Giuggiola, Arnaud; Graf Pannatier, Elisabeth; Landolt, Werner; Schleppi, Patrick; Rigling, Andreas

2010-03-01

In Valais, Switzerland, Scots pines (Pinus sylvestris L.) are declining, mainly following drought. To assess the impact of drought on tree growth and survival, an irrigation experiment was initiated in 2003 in a mature pine forest, approximately doubling the annual precipitation. Tree crown transparency (lack of foliage) and leaf area index (LAI) were annually assessed. Seven irrigated and six control trees were felled in 2006, and needles, stem discs and branches were taken for growth analysis. Irrigation in 2004 and 2005, both with below-average precipitation, increased needle size, area and mass, stem growth and, with a 1-year delay, shoot length. This led to a relative decrease in tree crown transparency (-14%) and to an increase in stand LAI (+20%). Irrigation increased needle length by 70%, shoot length by 100% and ring width by 120%, regardless of crown transparency. Crown transparency correlated positively with mean needle size, shoot length and ring width and negatively with specific leaf area. Trees with high crown transparency (low growth, short needles) experienced similar increases in needle mass and growth with irrigation than trees with low transparency (high growth, long needles), indicating that seemingly declining trees were able to 'recover' when water supply became sufficient. A simple drought index before and during the irrigation explained most of the variation found in the parameters for both irrigated and control trees.

Effect of crown growing space on the development of young hardwood crop trees

Treesearch

Gary W. Miller

2000-01-01

Crown release of individual crop trees can be used to increase the growth and competitiveness of selected trees in young hardwood stands. Forest managers need information on the response of individual trees to such thinnings to prescribe stand treatments that meet specific management objectives. Codominant northern red oak (Quercus rubra L.),...

Canopy BRF simulation of forest with different crown shape and height in larger scale based on Radiosity method

NASA Astrophysics Data System (ADS)

Song, Jinling; Qu, Yonghua; Wang, Jindi; Wan, Huawei; Liu, Xiaoqing

2007-06-01

Radiosity method is based on the computer simulation of 3D real structures of vegetations, such as leaves, branches and stems, which are composed by many facets. Using this method we can simulate the canopy reflectance and its bidirectional distribution of the vegetation canopy in visible and NIR regions. But with vegetations are more complex, more facets to compose them, so large memory and lots of time to calculate view factors are required, which are the choke points of using Radiosity method to calculate canopy BRF of lager scale vegetation scenes. We derived a new method to solve the problem, and the main idea is to abstract vegetation crown shapes and to simplify their structures, which can lessen the number of facets. The facets are given optical properties according to the reflectance, transmission and absorption of the real structure canopy. Based on the above work, we can simulate the canopy BRF of the mix scenes with different species vegetation in the large scale. In this study, taking broadleaf trees as an example, based on their structure characteristics, we abstracted their crowns as ellipsoid shells, and simulated the canopy BRF in visible and NIR regions of the large scale scene with different crown shape and different height ellipsoids. Form this study, we can conclude: LAI, LAD the probability gap, the sunlit and shaded surfaces are more important parameter to simulate the simplified vegetation canopy BRF. And the Radiosity method can apply us canopy BRF data in any conditions for our research.

Origin of buds, branches, and sprouts

Treesearch

Kevin T. Smith

2014-01-01

Recent research shows that survivor trees in rural, managed forests rebuild broken crowns with new branches and foliage after ice storm injury (Shortle et al. 2014). Veteran trees in historic parks and landscapes show repeated cycles of crown loss and recovery (Fay 2002). Crown rebuilding or reiteration from sprouts is a physiological response with architectural...

Section-Based Tree Species Identification Using Airborne LIDAR Point Cloud

NASA Astrophysics Data System (ADS)

Yao, C.; Zhang, X.; Liu, H.

2017-09-01

The application of LiDAR data in forestry initially focused on mapping forest community, particularly and primarily intended for largescale forest management and planning. Then with the smaller footprint and higher sampling density LiDAR data available, detecting individual tree overstory, estimating crowns parameters and identifying tree species are demonstrated practicable. This paper proposes a section-based protocol of tree species identification taking palm tree as an example. Section-based method is to detect objects through certain profile among different direction, basically along X-axis or Y-axis. And this method improve the utilization of spatial information to generate accurate results. Firstly, separate the tree points from manmade-object points by decision-tree-based rules, and create Crown Height Mode (CHM) by subtracting the Digital Terrain Model (DTM) from the digital surface model (DSM). Then calculate and extract key points to locate individual trees, thus estimate specific tree parameters related to species information, such as crown height, crown radius, and cross point etc. Finally, with parameters we are able to identify certain tree species. Comparing to species information measured on ground, the portion correctly identified trees on all plots could reach up to 90.65 %. The identification result in this research demonstrate the ability to distinguish palm tree using LiDAR point cloud. Furthermore, with more prior knowledge, section-based method enable the process to classify trees into different classes.

[Health assessment of individual trees in natural Larix gmelinii forest in Great Xing' an Mountains of China].

PubMed

Zhu, Yu; Liu, Zhao-Gang; Jin, Guang-Ze

2013-05-01

To integrate the health assessment results of individual trees into the health assessment of subcompartment (or stand) scale could improve the accuracy of subcompartment (or stand) scale health assessment, and realize the coupling process between the individual tree scale and the subcompartment (or stand) scale, providing a theoretical basis for the realization of forest health management. Taking the natural Larix gmelinii forest in Great Xing' an Mountains as the object, a health assessment indicators system of individual trees was established, which included root state, canopy defoliation degree, crown transparency, crown overlap, crown dieback ratio, live crown ratio, crown skewness, and vertical competition index. The principal component analysis (PCA) was employed to eliminate the correlations, the entropy value method was adopted to confirm the weight of each indicator, and the health status of individual L. gmelinii was assessed by fuzzy synthetic evaluation (FSE) method. Based on the health assessment results, a prediction model of the individual tree health was established by discriminant analysis (DA) method. The results showed that the trees in sub-healthy gradation were up to 36.7%, and those in healthy gradation only reached 12.9%. The proportion of the trees in unhealthy gradation exceeded that of the trees in healthy gradation, occupying 21.1% of the total. The prediction accuracy of the established model was 86.3%. More rational and effective management measures should be taken to improve the tree health grade.

Releasing young hardwood crop trees-use of a chain saw costs less than herbicides

Treesearch

Gary W. Miller; Gary W. Miller

1984-01-01

A crown-touching release of 12-year-old black cherry and yellow-poplar crop trees on a good site required removing an average of 14 trees for every crop tree. An average of 80 crop trees per acre was left free-to-grow with an average growing space of 4.7 feet on all sides of the crown. Basal spraying cost $0.80 per crop tree, stem injecting cost $0.61 per crop tree,...

Crown cover chart for oak savannas. Forest Service technical brief

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

Law, J.R.; Johnson, P.S.; Houf, G.

1994-07-01

Although oak savannas have been defined in many ways, they are characterized by scattered trees, largely comprised of oaks, and a sparse ground layer rich in grasses and forbs. The crown cover chart can be used to estimate the crown cover of trees as a percent of total area. Potential applications of the chart include monitoring changes in savanna crown cover, determining needed reductions in crown cover, and defining the savanna state. in restoring savannas that have grown into closed canopy stands, one can use the chart to estimate initial crown cover before restoration work is begun and again aftermore » crown cover has been reduced.« less

Variation in crown light utilization characteristics among tropical canopy trees.

PubMed

Kitajima, Kaoru; Mulkey, Stephen S; Wright, S Joseph

2005-02-01

Light extinction through crowns of canopy trees determines light availability at lower levels within forests. The goal of this paper is the exploration of foliage distribution and light extinction in crowns of five canopy tree species in relation to their shoot architecture, leaf traits (mean leaf angle, life span, photosynthetic characteristics) and successional status (from pioneers to persistent). Light extinction was examined at three hierarchical levels of foliage organization, the whole crown, the outermost canopy and the individual shoots, in a tropical moist forest with direct canopy access with a tower crane. Photon flux density and cumulative leaf area index (LAI) were measured at intervals of 0.25-1 m along multiple vertical transects through three to five mature tree crowns of each species to estimate light extinction coefficients (K). Cecropia longipes, a pioneer species with the shortest leaf life span, had crown LAI <0.5. Among the remaining four species, crown LAI ranged from 2 to 8, and species with orthotropic terminal shoots exhibited lower light extinction coefficients (0.35) than those with plagiotropic shoots (0.53-0.80). Within each type, later successional species exhibited greater maximum LAI and total light extinction. A dense layer of leaves at the outermost crown of a late successional species resulted in an average light extinction of 61% within 0.5 m from the surface. In late successional species, leaf position within individual shoots does not predict the light availability at the individual leaf surface, which may explain their slow decline of photosynthetic capacity with leaf age and weak differentiation of sun and shade leaves. Later-successional tree crowns, especially those with orthotropic branches, exhibit lower light extinction coefficients, but greater total LAI and total light extinction, which contribute to their efficient use of light and competitive dominance.

Linking ice accretion and crown structure: towards a model of the effect of freezing rain on tree canopies.

PubMed

Nock, Charles A; Lecigne, Bastien; Taugourdeau, Olivier; Greene, David F; Dauzat, Jean; Delagrange, Sylvain; Messier, Christian

2016-06-01

Despite a longstanding interest in variation in tree species vulnerability to ice storm damage, quantitative analyses of the influence of crown structure on within-crown variation in ice accretion are rare. In particular, the effect of prior interception by higher branches on lower branch accumulation remains unstudied. The aim of this study was to test the hypothesis that intra-crown ice accretion can be predicted by a measure of the degree of sheltering by neighbouring branches. Freezing rain was artificially applied to Acer platanoides L., and in situ branch-ice thickness was measured directly and from LiDAR point clouds. Two models of freezing rain interception were developed: 'IceCube', which uses point clouds to relate ice accretion to a voxel-based index (sheltering factor; SF) of the sheltering effect of branch elements above a measurement point; and 'IceTree', a simulation model for in silico evaluation of the interception pattern of freezing rain in virtual tree crowns. Intra-crown radial ice accretion varied strongly, declining from the tips to the bases of branches and from the top to the base of the crown. SF for branches varied strongly within the crown, and differences among branches were consistent for a range of model parameters. Intra-crown variation in ice accretion on branches was related to SF (R(2) = 0·46), with in silico results from IceTree supporting empirical relationships from IceCube. Empirical results and simulations confirmed a key role for crown architecture in determining intra-crown patterns of ice accretion. As suspected, the concentration of freezing rain droplets is attenuated by passage through the upper crown, and thus higher branches accumulate more ice than lower branches. This is the first step in developing a model that can provide a quantitative basis for investigating intra-crown and inter-specific variation in freezing rain damage. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Pruning Black Cherry in Understocked Stands

Treesearch

Ted J. Grisez

1978-01-01

Black cherry trees 4 to 6 inches in diameter at breast height (dbh) with live crown ratios ranging from 73 to 92 percent were pruned to 25, 50, or 75 percent of tree height or were left unpruned. Most trees can be pruned to 50 percent of tree height in one operation. Trees that have large crowns and that are frilly exposed on the southwest side should be pruned less...

Wood formation from the base to the crown in Pinus radiata: gradients of tracheid wall thickness, wood density, radial growth rate and gene expression

Treesearch

Sheree Cato; Lisa McMillan; Lloyd Donaldson; Thomas Richardson; Craig Echt; Richard Gardner

2006-01-01

Wood formation was investigated at five heights along the bole for two unrelated trees of Pinus radiataBoth trees showed clear gradients in wood properties from the base to the crown. Cambial cells at the base of the tree were dividing 3.3-fold slower than those at the crown, while the average thickness of cell walls in wood was highest at the base....

Stem sapwood permeability in relation to crown dominance and site quality in self-thinning fire-origin lodgepole pine stands.

PubMed

Reid, Douglas E B; Silins, Uldis; Lieffers, Victor J

2003-08-01

Stem sapwood hydraulic permeability, tree leaf area, sapwood basal area, earlywood to latewood ratio of annual rings, radial variation in hydraulic permeability and stem hydraulic capacity were examined in dominant (D), codominant (CD) and suppressed (SP) lodgepole pine (Pinus contorta Dougl. ex Loud.) trees growing on medium and poor sites. Hydraulic permeability on a sapwood area basis (ks) was lower in suppressed trees (0.71 x 10(-12) m2) compared to dominants (1.97 x 10(-12) m2) and codominants (1.79 x 10(-12) m2), and higher on medium than on poor sites. The leaf/sapwood area ratio (S) varied with crown dominance position (D > CD > SP) but not by site type. Leaf specific conductivity (kL) did not vary between crown classes or site types. The relationship between leaf area and stem hydraulic supply capacity (Q*) was strong, but differed among crown classes. Dominant trees and trees from the medium sites had a greater proportion of earlywood in outer rings of sapwood than suppressed trees. Sapwood permeability declined from the cambium to the sapwood-heartwood boundary in all samples, but the decline was more gradual in dominant trees compared to codominant and suppressed trees; differences in the radial variation in sapwood permeability may be related to differences in S. Sapwood permeability is positively related to crown dominance, whereas subdominant (CD and SP) trees have greater Q* in relation to leaf area, leading us to propose that this may give subdominant trees a survival advantage, slowing self-thinning.

3D Tree Dimensionality Assessment Using Photogrammetry and Small Unmanned Aerial Vehicles

PubMed Central

2015-01-01

Detailed, precise, three-dimensional (3D) representations of individual trees are a prerequisite for an accurate assessment of tree competition, growth, and morphological plasticity. Until recently, our ability to measure the dimensionality, spatial arrangement, shape of trees, and shape of tree components with precision has been constrained by technological and logistical limitations and cost. Traditional methods of forest biometrics provide only partial measurements and are labor intensive. Active remote technologies such as LiDAR operated from airborne platforms provide only partial crown reconstructions. The use of terrestrial LiDAR is laborious, has portability limitations and high cost. In this work we capitalized on recent improvements in the capabilities and availability of small unmanned aerial vehicles (UAVs), light and inexpensive cameras, and developed an affordable method for obtaining precise and comprehensive 3D models of trees and small groups of trees. The method employs slow-moving UAVs that acquire images along predefined trajectories near and around targeted trees, and computer vision-based approaches that process the images to obtain detailed tree reconstructions. After we confirmed the potential of the methodology via simulation we evaluated several UAV platforms, strategies for image acquisition, and image processing algorithms. We present an original, step-by-step workflow which utilizes open source programs and original software. We anticipate that future development and applications of our method will improve our understanding of forest self-organization emerging from the competition among trees, and will lead to a refined generation of individual-tree-based forest models. PMID:26393926

3D Tree Dimensionality Assessment Using Photogrammetry and Small Unmanned Aerial Vehicles.

PubMed

Gatziolis, Demetrios; Lienard, Jean F; Vogs, Andre; Strigul, Nikolay S

2015-01-01

Detailed, precise, three-dimensional (3D) representations of individual trees are a prerequisite for an accurate assessment of tree competition, growth, and morphological plasticity. Until recently, our ability to measure the dimensionality, spatial arrangement, shape of trees, and shape of tree components with precision has been constrained by technological and logistical limitations and cost. Traditional methods of forest biometrics provide only partial measurements and are labor intensive. Active remote technologies such as LiDAR operated from airborne platforms provide only partial crown reconstructions. The use of terrestrial LiDAR is laborious, has portability limitations and high cost. In this work we capitalized on recent improvements in the capabilities and availability of small unmanned aerial vehicles (UAVs), light and inexpensive cameras, and developed an affordable method for obtaining precise and comprehensive 3D models of trees and small groups of trees. The method employs slow-moving UAVs that acquire images along predefined trajectories near and around targeted trees, and computer vision-based approaches that process the images to obtain detailed tree reconstructions. After we confirmed the potential of the methodology via simulation we evaluated several UAV platforms, strategies for image acquisition, and image processing algorithms. We present an original, step-by-step workflow which utilizes open source programs and original software. We anticipate that future development and applications of our method will improve our understanding of forest self-organization emerging from the competition among trees, and will lead to a refined generation of individual-tree-based forest models.

Crown development: an index of stand density

Treesearch

John E. Krajicek; Kenneth A. Brinkman

1957-01-01

A study of crown characteristics of several hundred open-grown oak, hickory, and Norway spruce trees in Iowa revealed a high correlation between stem diameter and crown area. Consideration of this relationship led to the idea that perhaps here was a realistic way to measure and evaluate stand density or stocking. If, given unlimited growing space, trees of a certain...

Characterizing tree canopy temperature heterogeneity using an unmanned aircraft-borne thermal imager

NASA Astrophysics Data System (ADS)

Messinger, M.; Powell, R.; Silman, M.; Wright, M.; Nicholson, W.

2013-12-01

Leaf temperature (Tleaf) is an important control on many physiological processes such as photosynthesis and respiration, is a key variable for characterizing canopy energy fluxes, and is a valuable metric for identifying plant water stress or disease. Traditional methods of Tleaf measurement involve either the use of thermocouples, a time and labor-intensive method that samples sparsely in space, or the use of air temperature (Tair) as a proxy measure, which can introduce inaccuracies due to near constant canopy-atmosphere energy flux. Thermal infrared (TIR) imagery provides an efficient means of collecting Tleaf for large areas. Existing satellite and aircraft-based TIR imagery is, however, limited by low spatial and/or temporal resolution, while crane-mounted camera systems have strictly limited spatial extents. Unmanned aerial systems (UAS) offer new opportunities to acquire high spatial and temporal resolution imagery on demand. Here, we demonstrate the feasibility of collecting tree canopy Tleaf data using a small multirotor UAS fitted with a high spatial resolution TIR imager. The goals of this pilot study were to a) characterize basic patterns of within crown Tleaf for 4 study species and b) identify trends in Tleaf between species with varying leaf morphologies and canopy structures. TIR imagery was acquired for individual tree crowns of 4 species common to the North Carolina Piedmont ecoregion (Quercus phellos, Pinus strobus, Liriodendron tulipifera, Magnolia grandiflora) in an urban park environment. Due to significantly above-average summer precipitation, we assumed that none of the sampled trees was limited by soil water availability. We flew the TIR imaging system over 3-4 individuals of each of the 4 target species on 3 separate days. Imagery of all individuals was collected within the same 2-hour period in the afternoon on all days. There was low wind and partly cloudy skies during imaging. Tair, relative humidity, and wind speed were recorded at each site. Emissivity was assumed to be 0.98 for all species. Acquired images had a pixel resolution of <3 cm and measurement accuracy of ×1° C. We found the UAS-borne TIR imaging system to be an effective tool for collection of high resolution canopy imagery. The system imaged all targeted crowns quickly and reliably, providing a viable alternative to current methods of canopy Tleaf measurement. Analysis of the imagery indicated significant variability in Tleaf both within and between crowns. We identified trends in Tleaf related to average leaf size, shape, and crown structural traits. These data on the heterogeneity of Tleaf can further our understanding of canopy-atmosphere energy exchange. This pilot study demonstrates the promise of UAS-borne TIR sensors for acquiring high spatial resolution imagery at the scale of individual tree crowns.

Crown dynamics and wood production of Douglas-fir trees in an old-growth forest

Treesearch

H. Roaki Ishii; Stephen C. Sillett; Allyson L. Carroll

2017-01-01

Large trees are the most prominent structural features of old-growth forests, which are considered to be globally important carbon sinks. Because of their large size, estimates of biomass and growth of large trees are often based on ground-level measurements (e.g., diameter at breast height, DBH) and little is known about growth dynamics within the crown. As trees...

Modeling Caribbean tree stem diameters from tree height and crown width measurements

Treesearch

Thomas Brandeis; KaDonna Randolph; Mike Strub

2009-01-01

Regression models to predict diameter at breast height (DBH) as a function of tree height and maximum crown radius were developed for Caribbean forests based on data collected by the U.S. Forest Service in the Commonwealth of Puerto Rico and Territory of the U.S. Virgin Islands. The model predicting DBH from tree height fit reasonably well (R2 = 0.7110), with...

Linking ice accretion and crown structure: towards a model of the effect of freezing rain on tree canopies

PubMed Central

Nock, Charles A.; Lecigne, Bastien; Taugourdeau, Olivier; Greene, David F.; Dauzat, Jean; Delagrange, Sylvain; Messier, Christian

2016-01-01

Background and Aims Despite a longstanding interest in variation in tree species vulnerability to ice storm damage, quantitative analyses of the influence of crown structure on within-crown variation in ice accretion are rare. In particular, the effect of prior interception by higher branches on lower branch accumulation remains unstudied. The aim of this study was to test the hypothesis that intra-crown ice accretion can be predicted by a measure of the degree of sheltering by neighbouring branches. Methods Freezing rain was artificially applied to Acer platanoides L., and in situ branch-ice thickness was measured directly and from LiDAR point clouds. Two models of freezing rain interception were developed: ‘IceCube’, which uses point clouds to relate ice accretion to a voxel-based index (sheltering factor; SF) of the sheltering effect of branch elements above a measurement point; and ‘IceTree’, a simulation model for in silico evaluation of the interception pattern of freezing rain in virtual tree crowns. Key Results Intra-crown radial ice accretion varied strongly, declining from the tips to the bases of branches and from the top to the base of the crown. SF for branches varied strongly within the crown, and differences among branches were consistent for a range of model parameters. Intra-crown variation in ice accretion on branches was related to SF (R2 = 0·46), with in silico results from IceTree supporting empirical relationships from IceCube. Conclusions Empirical results and simulations confirmed a key role for crown architecture in determining intra-crown patterns of ice accretion. As suspected, the concentration of freezing rain droplets is attenuated by passage through the upper crown, and thus higher branches accumulate more ice than lower branches. This is the first step in developing a model that can provide a quantitative basis for investigating intra-crown and inter-specific variation in freezing rain damage. PMID:27107412

Crown area equations for 13 species of trees and shrubs in northern California and southwestern Oregon

Treesearch

Fabian C.C. Uzoh; Martin W. Ritchie

1996-01-01

The equations presented predict crown area for 13 species of trees and shrubs which may be found growing in competition with commercial conifers during early stages of stand development. The equations express crown area as a function of basal area and height. Parameters were estimated for each species individually using weighted nonlinear least square regression.

Correlations between tree crown condition and shade tolerance, crown form, and light availability

Treesearch

KaDonna C. Randolph

2007-01-01

Individual tree crown condition is the result of a combination of many factors including genetic traits, growing site characteristics, and past and present external stresses (e.g., drought, insect outbreaks, fire, etc.). Shade tolerance and the extent to which terminal buds control the length and orientation of lateral branches (epinastic control) are the two primary...

An alternative method for estimating crown characteristics of urban trees using digital photographs

Treesearch

Matthew F. Winn; Philip A. Araman

2012-01-01

The USDA Forest Service Forest Inventory and Analysis (FIA) program has concluded that statewide urban forest inventories are feasible based on a series of pilot studies initiated in 2001. However, much of the tree crown data collected during inventories are based on visual inspection and therefore highly subjective. In order to objectively determine the crown...

Effects of photographic distance on tree crown atributes calculated using urbancrowns image analysis software

Treesearch

Mason F. Patterson; P. Eric Wiseman; Matthew F. Winn; Sang-mook Lee; Philip A. Araman

2011-01-01

UrbanCrowns is a software program developed by the USDA Forest Service that computes crown attributes using a side-view digital photograph and a few basic field measurements. From an operational standpoint, it is not known how well the software performs under varying photographic conditions for trees of diverse size, which could impact measurement reproducibility and...

Genetic variation in tree structure and its relation to size in Douglas-fir: II. crown form, branch characters, and foliage characters.

Treesearch

J.B. St. Clair

1994-01-01

Genetic variation and covariation among traits of tree size and structure were assessed in an 18-year-old Douglas-fir (Pseudotsuga menziesii var. menziesii (Mirb.) Franco) genetic test in the Coast Range of Oregon. Considerable genetic variation was found for relative crown width; stem increment per crown projection area; leaf...

Estimating Vegetation Structure in African Savannas using High Spatial Resolution Imagery

NASA Astrophysics Data System (ADS)

Axelsson, C.; Hanan, N. P.

2016-12-01

High spatial resolution satellite imagery allows for detailed mapping of trees in savanna landscapes, including estimates of woody cover, tree densities, crown sizes, and the spatial pattern of trees. By linking these vegetation parameters to rainfall and soil properties we gain knowledge of how the local environment influences vegetation. A thorough understanding of the underlying ecosystem processes is key to assessing the future productivity and stability of these ecosystems. In this study, we have processed and analyzed hundreds of sites sampled from African savannas across a wide range of rainfall and soil conditions. The vegetation at each site is classified using unsupervised classification with manual assignment into woody, herbaceous and bare cover classes. A crown delineation method further divides the woody areas into individual tree crowns. The results show that rainfall, soil, and topography interactively influence vegetation structure. We see that both total rainfall and rainfall seasonality play important roles and that soil type influences woody cover and the sizes of tree crowns.

Community patterns of tropical tree phenology derived from Unmanned Aerial Vehicle images: intra- and interspecific variation, association with species plant traits, and response to interannual climate variation

NASA Astrophysics Data System (ADS)

Bohlman, Stephanie; Rifai, Sami; Park, John; Dandois, Jonathan; Muller-Landau, Helene

2017-04-01

Phenology is a key life history trait of plant species and critical driver of ecosystem processes. There is strong evidence that phenology is shifting in temperate ecosystems in response to climate change, but tropical forest phenology remains poorly quantified and understood. A key challenge is that tropical forests contain hundreds of plant species with a wide variety of phenological patterns, which makes it difficult to collect sufficient ground-based field data to characterize individual tropical tree species phenologies. Satellite-based observations, an important source of phenology data in northern latitudes, are hindered by frequent cloud cover in the tropics. To quantify phenology over a large number of individuals and species, we collected bi-weekly images from unmanned aerial vehicles (UAVs) in the well-studied 50-ha forest inventory plot on Barro Colorado Island, Panama. The objective of this study is to quantify inter- and intra-specific responses of tropical tree leaf phenology to environmental variation over large spatial scales and identify key environmental variables and physiological mechanisms underpinning phenological variation. Between October 2014 and December 2015 and again in May 2015, we collected a total of 35 sets of UAV images, each with continuous coverage of the 50-ha plot, where every tree ≥ 1 cm DBH is mapped. UAV imagery was corrected for exposure, orthorectified, and then processed to extract spectral, texture, and image information for individual tree crowns, which was then used as inputs for a machine learning algorithm that successfully predicted the percentages of leaf, branch, and flower cover for each tree crown (r2=0.76 between observed and predicted percent branch cover for individual tree crowns). We then quantified cumulative annual deciduousness for each crown by fitting a non-parametric curve of flexible shape to its predicted percent branch time series and calculated the area under the curve. We obtained the species identities of 2000 crowns in the images by linking the crowns to stem tags in the field, thus producing a time series of cumulative annual deciduousness for 65 species. Deciduousness showed continuous variation among species rather than distinct phenological categories (ie evergreen and deciduous) that are commonly used in physiological, ecosystem and modeling studies. Some species labelled as evergreen by expert-based classification had annual deciduousness higher than those labelled as deciduous. We found significant, positive relationships between species mean deciduousness and species' leaf phosphorous, photosynthetic capacity and adult relative growth rate, suggesting that higher deciduousness is associated with greater resource acquisition. Comparing May 2015 (during an El Nino drought) and May 2014 (an non El Nino year with normal rainfall), mean deciduousness values for nearly all species was greater in 2015 but with differing levels of intraspecific variation. We discuss how the variation in deciduousness among species, its relationship with plant traits and response to the drought might be incorporated into terrestrial biosphere models of tropical forests to more accurately represent phenology and understand the consequences of community-level variation in phenology for ecosystem processes.

Do isolated gallery-forest trees facilitate recruitment of forest seedlings and saplings in savannna?

NASA Astrophysics Data System (ADS)

Azihou, Akomian Fortuné; Glèlè Kakaï, Romain; Sinsin, Brice

2013-11-01

Facilitation is an ecological process that allows some species to establish in environments they can hardly afford in the absence of the process. This study investigated if the subcanopy of gallery-forest trees isolated in savanna is suitable for the early recruitment of forest woody species. We measured tree crown area as well as the density of seedlings and saplings of gallery-forest tree species beneath isolated trees and in the savanna matrix along 50 transects of 5-km long and 600 m wide located along four gallery forests. We then tested the nurse-plant effect and Janzen-Connell hypothesis beneath isolated trees. We also examined the relationships between the crown area and the density of seedlings and saplings. Among the eight identified tree species isolated in savanna, only Daniellia oliveri and Khaya senegalensis showed nurse-plant effect and promoted a significant, yet low early recruitment with a seedling-to-sapling survival of 0.044 and 0.578, respectively. The suitability of the subcanopy of isolated trees decreased with the recruitment progression and Janzen-Connell effects were absent. Seedlings had neutral association with the crown area of isolated trees which shifted to positive at the sapling stage. The species of the isolated tree and the crown area explained less than 20% of total variance, indicating that other predictive factors are important in explaining the nurse-plant effect observed in this study.

How does tree age influence damage and recovery in forests impacted by freezing rain and snow?

PubMed

Zhu, LiRong; Zhou, Ting; Chen, BaoMing; Peng, ShaoLin

2015-05-01

The response and recovery mechanisms of forests to damage from freezing rain and snow events are a key topic in forest research and management. However, the relationship between the degree of damage and tree age, i.e., whether seedlings, young trees, or adult trees are most vulnerable, remains unclear and is rarely reported. We investigated the effect of tree age on the degrees of vegetation damage and subsequent recovery in three subtropical forest types-coniferous, mixed, and broad-leaved-in the Tianjing Mountains, South China, after a series of rare icy rain and freezing snow events in 2008. The results showed that damage and recovery rates were both dependent on tree age, with the proportion of damaged vegetation increasing with age (estimated by diameter at breast height, DBH) in all three forest types and gradually plateauing. Significant variation occurred among forest types. Young trees in the coniferous forest were more vulnerable than those in the broad-leaved forest. The type of damage also varied with tree age in different ways in the three forest types. The proportion of young seedlings that were uprooted (the most severe type of damage) was highest in the coniferous forest. In the mixed forest, young trees were significantly more likely to be uprooted than seedlings and adult trees, while in the broad-leaved forest, the proportion of uprooted adult trees was significantly higher than that of seedlings and young trees. There were also differences among forest types in how tree age affected damage recovery. In the coniferous forest, the recovery rate of trees with broken trunks or crowns (DBH > 2.5 cm) increased with tree age. However, in the mixed and broad-leaved forests, no obvious correlation between the recovery rate of trees with broken trunks or crowns and tree age was observed. Trees with severe root damage did not recover; they were uprooted and died. In these forests, vegetation damage and recovery showed tree age dependencies, which varied with tree shape, forest type, and damage type. Understanding this dependency will guide restoration after freezing rain and snow disturbances.

Equations relating compacted and uncompacted live crown ratio for common tree species in the South

Treesearch

KaDonna C. Randolph

2010-01-01

Species-specific equations to predict uncompacted crown ratio (UNCR) from compacted live crown ratio (CCR), tree length, and stem diameter were developed for 24 species and 12 genera in the southern United States. Using data from the US Forest Service Forest Inventory and Analysis program, nonlinear regression was used to model UNCR with a logistic function. Model...

Largest-Crown- Width Prediction Models for 53 Species in the Western United States

Treesearch

William A. Bechtold

2004-01-01

The mean crown diameters of stand-grown trees 5.0-in. dbh and larger were modeled as a function of stem diameter, live-crown ratio, stand-level basal area, latitude, longitude, elevation, and Hopkins bioclimatic index for 53 tree species in the western United States. Stem diameter was statistically significant in all models, and a quadratic term for stem diameter was...

Carbon Sequestration Estimation of Street Trees Based on Point Cloud from Vehicle-Borne Laser Scanning System

NASA Astrophysics Data System (ADS)

Zhao, Y.; Hu, Q.

2017-09-01

Continuous development of urban road traffic system requests higher standards of road ecological environment. Ecological benefits of street trees are getting more attention. Carbon sequestration of street trees refers to the carbon stocks of street trees, which can be a measurement for ecological benefits of street trees. Estimating carbon sequestration in a traditional way is costly and inefficient. In order to solve above problems, a carbon sequestration estimation approach for street trees based on 3D point cloud from vehicle-borne laser scanning system is proposed in this paper. The method can measure the geometric parameters of a street tree, including tree height, crown width, diameter at breast height (DBH), by processing and analyzing point cloud data of an individual tree. Four Chinese scholartree trees and four camphor trees are selected for experiment. The root mean square error (RMSE) of tree height is 0.11m for Chinese scholartree and 0.02m for camphor. Crown widths in X direction and Y direction, as well as the average crown width are calculated. And the RMSE of average crown width is 0.22m for Chinese scholartree and 0.10m for camphor. The last calculated parameter is DBH, the RMSE of DBH is 0.5cm for both Chinese scholartree and camphor. Combining the measured geometric parameters and an appropriate carbon sequestration calculation model, the individual tree's carbon sequestration will be estimated. The proposed method can help enlarge application range of vehicle-borne laser point cloud data, improve the efficiency of estimating carbon sequestration, construct urban ecological environment and manage landscape.

Do trees fall downhill? Relationship between treefall direction and slope-aspect and wind in eight old-growth oak stands in the central hardwood forest

Treesearch

James S. Rentch

2011-01-01

This study examined the relationship between direction of treefall and slope-aspect, and prevailing wind in eight old-growth stands where single-tree canopy gaps characterize the dominant disturbance regime. All live and downed trees were inventoried in 0.45-ha sample plots. To determine crown asymmetry, crown sizes of live trees were measured along two perpendicular...

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

A tool to determine crown and plot canopy transparency for forest inventory and analysis phase 3 plots using digital photographs

Treesearch

Matthew F. Winn; Philip A. Araman

2012-01-01

The USDA Forest Service Forest Inventory and Analysis (FIA) program collects crown foliage transparency estimates for individual trees on Phase 3 (P3) inventory plots. The FIA crown foliage estimate is obtained from a pair of perpendicular side views of the tree. Researchers with the USDA Forest Service Southern Research Station have developed a computer program that...

Response of branch growth and mortality to silvicultural treatments in coastal Douglas-fir plantations: implications for predicting tree growth.

Treesearch

A.R. Weiskittel; D. Maguire; R.A. Monserud

2007-01-01

Static models of individual tree crown attributes such as height to crown base and maximum branch diameter profile have been developed for several commercially important species. Dynamic models of individual branch growth and mortality have received less attention, but have generally been developed retrospectively by dissecting felled trees; however, this approach is...

A structurally based analytic model for estimation of biomass and fuel loads of woodland trees

Treesearch

Robin J. Tausch

2009-01-01

Allometric/structural relationships in tree crowns are a consequence of the physical, physiological, and fluid conduction processes of trees, which control the distribution, efficient support, and growth of foliage in the crown. The structural consequences of these processes are used to develop an analytic model based on the concept of branch orders. A set of...

Needle-Age Related Variability in Nitrogen, Mobile Carbohydrates, and δ13C within Pinus koraiensis Tree Crowns

PubMed Central

Yan, Cai-Feng; Han, Shi-Jie; Zhou, Yu-Mei; Wang, Cun-Guo; Dai, Guan-Hua; Xiao, Wen-Fa; Li, Mai-He

2012-01-01

For both ecologists and physiologists, foliar physioecology as a function of spatially and temporally variable environmental factors such as sunlight exposure within a tree crown is important for understanding whole tree physiology and for predicting ecosystem carbon balance and productivity. Hence, we studied concentrations of nitrogen (N), non-structural carbohydrates (NSC = soluble sugars + starch), and δ13C in different-aged needles within Pinus koraiensis tree crowns, to understand the needle age- and crown position-related physiology, in order to test the hypothesis that concentrations of N, NSC, and δ13C are needle-age and crown position dependent (more light, more photosynthesis affecting N, NSC, and δ13C), and to develop an accurate sampling strategy. The present study indicated that the 1-yr-old needles had significantly higher concentration levels of mobile carbohydrates (both on a mass and an area basis) and Narea (on an area basis), as well as NSC-N ratios, but significantly lower levels of Nmass (on a mass basis) concentration and specific leaf area (SLA), compared to the current-year needles. Azimuthal (south-facing vs. north-facing crown side) effects were found to be significant on starch [both on a mass (STmass) and an area basis (STarea)], δ13C values, and Narea, with higher levels in needles on the S-facing crown side than the N-facing crown side. Needle Nmass concentrations significantly decreased but needle STmass, STarea, and δ13C values significantly increased with increasing vertical crown levels. Our results suggest that the sun-exposed crown position related to photosynthetic activity and water availability affects starch accumulation and carbon isotope discrimination. Needle age associated with physiological activity plays an important role in determining carbon and nitrogen physiology. The present study indicates that across-scale sampling needs to carefully select tissue samples with equal age from a comparable crown position. PMID:22493732

Predicting the limits to tree height using statistical regressions of leaf traits.

PubMed

Burgess, Stephen S O; Dawson, Todd E

2007-01-01

Leaf morphology and physiological functioning demonstrate considerable plasticity within tree crowns, with various leaf traits often exhibiting pronounced vertical gradients in very tall trees. It has been proposed that the trajectory of these gradients, as determined by regression methods, could be used in conjunction with theoretical biophysical limits to estimate the maximum height to which trees can grow. Here, we examined this approach using published and new experimental data from tall conifer and angiosperm species. We showed that height predictions were sensitive to tree-to-tree variation in the shape of the regression and to the biophysical endpoints selected. We examined the suitability of proposed end-points and their theoretical validity. We also noted that site and environment influenced height predictions considerably. Use of leaf mass per unit area or leaf water potential coupled with vulnerability of twigs to cavitation poses a number of difficulties for predicting tree height. Photosynthetic rate and carbon isotope discrimination show more promise, but in the second case, the complex relationship between light, water availability, photosynthetic capacity and internal conductance to CO(2) must first be characterized.

Remote Sensing Protocols for Parameterizing an Individual, Tree-Based, Forest Growth and Yield Model

DTIC Science & Technology

2014-09-01

Leaf-Off Tree Crowns in Small Footprint, High Sampling Density LIDAR Data from Eastern Deciduous Forests in North America.” Remote Sensing of...William A. 2003. “Crown-Diameter Prediction Models for 87 Species of Stand- Grown Trees in the Eastern United States.” Southern Journal of Applied...ER D C/ CE RL T R- 14 -1 8 Base Facilities Environmental Quality Remote Sensing Protocols for Parameterizing an Individual, Tree -Based

Monitoring water stress and fruit quality in an orange orchard under regulated deficit irrigation using narrow-band structural and physiological remote sensing indices

NASA Astrophysics Data System (ADS)

Stagakis, S.; González-Dugo, V.; Cid, P.; Guillén-Climent, M. L.; Zarco-Tejada, P. J.

2012-07-01

This paper deals with the monitoring of water status and the assessment of the effect of stress on citrus fruit quality using structural and physiological remote sensing indices. Four flights were conducted over a citrus orchard in 2009 using an unmanned aerial vehicle (UAV) carrying a multispectral camera with six narrow spectral bands in the visible and near infrared. Physiological indices such as the Photochemical Reflectance Index (PRI570), a new structurally robust PRI formulation that uses the 515 nm as the reference band (PRI515), and a chlorophyll ratio (R700/R670) were compared against the Normalized Difference Vegetation Index (NDVI), Renormalized Difference Vegetation Index (RDVI) and Modified Triangular Vegetation Index (MTVI) canopy structural indices for their performance in tracking water status and the effects of sustained water stress on fruit quality at harvest. The irrigation setup in the commercial orchard was compared against a treatment scheduled to satisfy full requirements (based on estimated crop evapotranspiration) using two regulated deficit irrigation (RDI) strategies. The water status of the trees throughout the experiment was monitored with frequent field measurements of stem water potential (Ψx), while titratable acidity (TA) and total soluble solids (TSS) were measured at harvest on selected trees from each irrigation treatment. The high spatial resolution of the multispectral imagery (30 cm pixel size) enabled identification of pure tree crown components, extracting the tree reflectance from shaded, sunlit and aggregated pixels. The physiological and structural indices were then calculated from each tree at the following levels: (i) pure sunlit tree crown, (ii) entire crown, aggregating the within-crown shadows, and (iii) simulating a lower resolution pixel, including tree crown, sunlit and shaded soil pixels. The resulting analysis demonstrated that both PRI formulations were able to track water status, except when water stress altered canopy structure. In such cases, PRI570 was more affected than PRI515 by the structural changes caused by sustained water stress throughout the season. Both PRI formulations were proven to serve as pre-visual water stress indicators linked to fruit quality TSS and TA parameters (r2 = 0.69 for PRI515 vs TSS; r2 = 0.58 vs TA). In contrast, the chlorophyll (R700/R670) and structural indices (NDVI, RDVI, MTVI) showed poor relationships with fruit quality and water status levels (r2 = 0.04 for NDVI vs TSS; r2 = 0.19 vs TA). The two PRI formulations showed strong relationships with the field-measured fruit quality parameters in September, the beginning of stage III, which appeared to be the period most sensitive to water stress and the most critical for assessing fruit quality in citrus. Both PRI515 and PRI570 showed similar performance for the two scales assessed (sunlit crown and entire crown), demonstrating that within-crown component separation is not needed in citrus tree crowns where the shaded vegetation component is small. However, the simulation conducted through spatial resampling on tree + soil aggregated pixels revealed that the physiological indices were highly affected by soil reflectance and between-tree shadows, showing that for TSS vs PRI515 the relationship dropped from r2 = 0.69 to r2 = 0.38 when aggregating soil + crown components. This work confirms a previous study that demonstrated the link between PRI570, water stress, and fruit quality, while also making progress in assessing the new PRI formulation (PRI515), the within-crown shadow effects on the physiological indices, and the need for high resolution imagery to target individual tree crowns for the purpose of evaluating the effects of water stress on fruit quality in citrus.

A Tree Taper Model Based on Similar Triangles and Use of Crown Ratio as a Measure of Form in Taper Equations for Longleaf Pine

Treesearch

Dennis J. Shaw; Ralph S. Meldahl; John S. Kush; Greg L. Somers

2003-01-01

We used data from 322 natural longleaf pine (Pinus palustris Mill.) trees to include crown ratio as a continuous variable in taper equations. The data were divided into 10 crown-ratio classes and fitted taper equations into each class to detect trends in the coefficients. For application to longleaf pine, we replaced coefficients that exhibited a...

Estimating the weight of crown segments for old-growth Douglas-fir and western hemlock.

Treesearch

J.A. Kendall Snell; Timothy A. Max

1985-01-01

The purpose of this study was to develop and validate estimators to predict total crown weight and weight of any segment of crown for old-growth felled and bucked Douglas-fir and western hemlock trees. Equations were developed for predicting weight of continuous live crown, total live crown, dead crown, any segment of live crown, and individual branches for old-growth...

Crop-tree release increases growth of 12-year-old yellow-poplar and black cherry

Treesearch

Neil I. Lamson; H. Clay Smith; H. Clay Smith

1989-01-01

Precommercial thinning was done in a 12-year-old Appalachian hardwood sapling stand in West Virginia. Two crop-tree release techniques were used--crown touching and crown touching plus 5 feet. Results indicated that both treatments significantly increased 5-year d.b.h. growth for released yellow-poplar and black cherry crop trees. Although there was a major increase in...

Energy values for whole trees and crowns of selected species.

Treesearch

James O. Howard

1988-01-01

Energy values, BTU's (British thermal units) per ovendry pound, were determined for whole-tree and crown materials from western hemlock (Tsuga heterophylla (Raf.) Sarg.), coast Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii), and western redcedar (Thuja plicata Donn ex D. Don)....

The influence of tree morphology on stemflow generation in a tropical lowland rainforest

NASA Astrophysics Data System (ADS)

Uber, Magdalena; Levia, Delphis F.; Zimmermann, Beate; Zimmermann, Alexander

2014-05-01

Even though stemflow usually accounts for only a small proportion of rainfall, it is an important point source of water and ion input to forest floors and may, for instance, influence soil moisture patterns and groundwater recharge. Previous studies showed that the generation of stemflow depends on a multitude of meteorological and biological factors. Interestingly, despite the tremendous progress in stemflow research during the last decades it is still largely unknown which combination of tree characteristics determines stemflow volumes in species-rich tropical forests. This knowledge gap motivated us to analyse the influence of tree characteristics on stemflow volumes in a 1 hectare plot located in a Panamanian lowland rainforest. Our study comprised stemflow measurements in six randomly selected 10 m by 10 m subplots. In each subplot we measured stemflow of all trees with a diameter at breast height (DBH) > 5 cm on an event-basis for a period of six weeks. Additionally, we identified all tree species and determined a set of tree characteristics including DBH, crown diameter, bark roughness, bark furrowing, epiphyte coverage, tree architecture, stem inclination, and crown position. During the sampling period, we collected 985 L of stemflow (0.98 % of total rainfall). Based on regression analyses and comparisons among plant functional groups we show that palms were most efficient in yielding stemflow due to their large inclined fronds. Trees with large emergent crowns also produced relatively large amounts of stemflow. Due to their abundance, understory trees contribute much to stemflow yield not on individual but on the plot scale. Even though parameters such as crown diameter, branch inclination and position of the crown influence stemflow generation to some extent, these parameters explain less than 30 % of the variation in stemflow volumes. In contrast to published results from temperate forests, we did not detect a negative correlation between bark roughness and stemflow volume. This is because other parameters such as crown diameter obscured this relationship. Due to multicollinearity and poor correlations between single tree characteristics with stemflow volume, an assessment of stemflow volumes based on forest characteristics remains cumbersome in highly diverse ecosystems. Instead of relying on regression relationships, we therefore advocate a total sampling of trees in several plots to determine stand-scale stemflow yield in tropical forests.

Effect of the physiognomy of Attalea butyracea (Arecoideae) on population density and age distribution of Rhodnius prolixus (Triatominae).

PubMed

Urbano, Plutarco; Poveda, Cristina; Molina, Jorge

2015-04-01

Rhodnius prolixus Stål, 1859 is one of the main vectors of Trypanosoma (Schyzotrypanum) cruzi Chagas, 1909. In its natural forest environment, this triatomine is mainly found in palm tree crowns, where it easily establishes and develops dense populations. The aim of this study was to evaluate the effect of the physiognomy and reproductive status of Attalea butyracea on the population relative density and age structure of R. prolixus and to determine the vector's population stratification according to the vertical and horizontal profile of an A. butyracea forest. Using live bait traps, 150 individuals of A. butyracea with different physiognomy and 40 individuals with similar physiognomy (crown size, number of leaves, palm tree height, diameter at breast height, reproductive status) were sampled for triatomines in Yopal, Casanare-Colombia. Temperature and relative humidity were measured in the crown of the palm tree. Entomological indices and natural infection rates were also determined. The relative population density of R. prolixus on natural A. butyracea groves is associated with the palm's height, number of leaves and crown volume. The young immature stages were present mostly at the crown's base and the advanced immature stages and adults were present mostly at the crown of the palm tree. This distribution correlates with the temperature stability and relative humidity in the base and the fluctuation of both environmental variables in the palm's crown. A higher density of R. prolixus was found as the palm tree height increased and as the distance of the palm with respect to the forest border decreased, especially towards anthropically intervened areas. A density index of 12.6 individuals per palm tree with an infestation index of 88.9% and a colonization index of 98.7% was observed. 85.2% was the infection index with T. cruzi. The physiognomy of palm trees affects the relative population density and the distribution of developmental stages of R. prolixus. Therefore, they constitute a risk factor for the potential migration of infected insects from wild environments towards residential environments and the subsequent epidemiological risk of transmission of T. cruzi to people.

Drought stress release increased growth rate but did not affect levels of storage carbohydrates in Scots pine trees

NASA Astrophysics Data System (ADS)

Schönbeck, Leonie; Gessler, Arthur; Rigling, Andreas; Schaub, Marcus; Li, Mai-He

2017-04-01

For trees, energy storage in the form of non-structural carbohydrates (NSCs) plays an important role for survival and growth, especially during stress events such as drought. It is hypothesized, that tree individuals that experience long-term drought stress use up larger amounts of NSCs than trees that do not experience drought. Consequently, such drought-induced depletion might lead to a decrease in tree vigor and carbon starvation, a mechanism that is subject of intensive debates in recent literature. Hence, if carbon starvation is occurring during drought, drought stress release should again increase NSC concentrations. A long-term (13 years) irrigation experiment is being conducted in the Pfyn forest, the largest Pinus sylvestris dominated forest in Switzerland, located in the dry inner-Alpine Swiss Rhone valley (average precipitation 600 mm/year, with frequent dry spells). Water addition ( 600 mm/year) is executed every year during the growing season between April and October. Tree height, stem diameter and crown transparency are being measured since 2003. In February, July and October 2015, roots, stem sapwood and needles were harvested from 30 irrigated and 30 control trees and 5 different crown transparency classes. Shoot length, needle morphology, soluble sugars, starch concentrations, needle δ13C and δ15N were measured. Shoot and stem growth were higher in irrigated trees than in control trees. Growth decreased with increasing crown transparency in both treatments. Only in July, needle starch levels were higher in irrigated trees than in control trees but there was no treatment effect for wood and root starch concentrations. Tissue starch and sugar levels were negatively correlated with crown transparency, particularly in the roots (p<0.001), independent of the treatment. Needle δ13C values were higher in the control trees than in the irrigated trees, where needle δ13C values were positively correlated with increasing transparency (p<0.01). Annual shoot growth was positively correlated with starch levels in the roots. The results show that 13 years of irrigation did lead to increased growth but not to increased NSC levels hence not confirming our initial hypothesis. δ13C levels indicate that control trees experienced more drought stress than irrigated trees. However, we found irrigated trees from high crown transparency classes with similar δ13C levels as for non-irrigated control trees. The release of drought stress has benefited the initially vital trees, whereas the initially inferior trees still show signs of drought stress. The results point to a 'winner takes it all principle', where differences between individuals increase when environment conditions improve. This caused the irrigation treatment not being effective in generally releasing drought stress and NSC depletion in all trees. As increasing crown transparency over both treatments is correlated with decreasing growth and decreasing NSC levels, there are still indications that reduced NSC is related to reduced tree vigor under drought.

Modeling tree crown dynamics with 3D partial differential equations.

PubMed

Beyer, Robert; Letort, Véronique; Cournède, Paul-Henry

2014-01-01

We characterize a tree's spatial foliage distribution by the local leaf area density. Considering this spatially continuous variable allows to describe the spatiotemporal evolution of the tree crown by means of 3D partial differential equations. These offer a framework to rigorously take locally and adaptively acting effects into account, notably the growth toward light. Biomass production through photosynthesis and the allocation to foliage and wood are readily included in this model framework. The system of equations stands out due to its inherent dynamic property of self-organization and spontaneous adaptation, generating complex behavior from even only a few parameters. The density-based approach yields spatially structured tree crowns without relying on detailed geometry. We present the methodological fundamentals of such a modeling approach and discuss further prospects and applications.

Significance of crown shape in the replacement of a central incisor with a single implant-supported crown.

PubMed

Gobbato, Luca; Paniz, Gianluca; Mazzocco, Fabio; Chierico, Andrea; Tsukiyama, Teppei; Levi, Paul A; Weisgold, Arnold S

2013-05-01

When utilizing a single implant-supported crown to replace a central incisor, understanding the final shape of the implant restoration is an important factor to help achieve a successful esthetic outcome. In today's dentistry, tooth shape is a critical factor when dental implant prostheses are considered in the esthetic zone. The major esthetic goal for this type of restoration is to achieve the closest possible symmetry with the adjacent tooth, both at the soft and at the hard tissue levels. The goal of this study was to objectively analyze the significance of natural crown shape when replacing a central incisor with a single implant-supported crown. In this study, we investigated the shape of the crowns of maxillary central incisors in 60 individuals who presented to our clinics with an untreatable central incisor. The presence of a dental diastema, "black triangle," presence or absence of gingival symmetry, and the presence or absence of dental symmetry were recorded in the pre- and postoperative photographs. Out of 60 patients, 33.3% had triangular-shaped crowns, 16.6% square/tapered, and 50% square-shaped crown form. After treatment was rendered, 65% of the triangular group, 40% of the square/tapered group, and 13.3% of the square group required an additional restoration on the adjacent central incisor in order to fulfill the esthetic needs of the patients. Data analysis revealed that if there is a "black triangle," a diastema, or presence of dental or gingival asymmetry, an additional restoration on the adjacent central incisor is often required in order to fulfill esthetic goals. The additional restoration is highly recommended in situations with a triangular crown shape, while it is suggested in cases of square/tapered and square tooth shapes in the presence of a dental diastema.

3D Forest: An application for descriptions of three-dimensional forest structures using terrestrial LiDAR

PubMed Central

Krůček, Martin; Vrška, Tomáš; Král, Kamil

2017-01-01

Terrestrial laser scanning is a powerful technology for capturing the three-dimensional structure of forests with a high level of detail and accuracy. Over the last decade, many algorithms have been developed to extract various tree parameters from terrestrial laser scanning data. Here we present 3D Forest, an open-source non-platform-specific software application with an easy-to-use graphical user interface with the compilation of algorithms focused on the forest environment and extraction of tree parameters. The current version (0.42) extracts important parameters of forest structure from the terrestrial laser scanning data, such as stem positions (X, Y, Z), tree heights, diameters at breast height (DBH), as well as more advanced parameters such as tree planar projections, stem profiles or detailed crown parameters including convex and concave crown surface and volume. Moreover, 3D Forest provides quantitative measures of between-crown interactions and their real arrangement in 3D space. 3D Forest also includes an original algorithm of automatic tree segmentation and crown segmentation. Comparison with field data measurements showed no significant difference in measuring DBH or tree height using 3D Forest, although for DBH only the Randomized Hough Transform algorithm proved to be sufficiently resistant to noise and provided results comparable to traditional field measurements. PMID:28472167

Clonal Propagation of walnut rootstock genotypes for genetic improvement 2010

USDA-ARS?s Scientific Manuscript database

The soilborne bacterium Agrobacterium tumefaciens is the causal agent of crown gall disease of walnut. Large tumors located near the crown of the tree are hallmark symptoms induced by the bacterial pathogen. Untreated tumors can have an adverse effect on tree health resulting in reduced nut yield an...

Modeling the spatial distribution of forest crown biomass and effects on fire behavior with FUEL3D and WFDS

Treesearch

Russell A. Parsons; William Mell; Peter McCauley

2010-01-01

Crown fire poses challenges to fire managers and can endanger fire fighters. Understanding of how fire interacts with tree crowns is essential to informed decisions about crown fire. Current operational crown fire predictions in the United States assume homogeneous crown fuels. While a new class of research fire models, which model fire behavior with computational...

Crown Recession Patterns in Three Conifer Species of the Northern Rocky Mountains

Treesearch

Sean M. Garber; Robert A. Monserud; Douglas A. Maguire

2008-01-01

Crown length is a fundamental tree dimension for characterizing growth potential, wildlife habitat, and wood quality. The relative rates of height growth and crown recession detennine the progression of crown length over time. We investigated patterns in crown recession of three co-occurring species in the northern Rocky Mountains: western white pine (Pinus...

An Index of Competition Based on Relative Crown Position and Size

Treesearch

Dwight D. O' Neal; Allan E. Houston; Edward R. Buckner; James S. Meadows

1995-01-01

A new competition index, the Crown Position Index (CPI) was evaluated using a 41-year-old, well stocked, upland hardwood stand in southwestern Tennessee. CPI wss based on relative crown position and crown size as expressed by crown projections and relative heights of crop trees and their competitors. Comparisons were made among CPI, the Hegyl (1974)...

Intensity of precommercial crop-tree release increases diameter and crown growth in upland hardwoods

Treesearch

Jeffrey S. Ward

1995-01-01

In 1988 seven study areas were established in Connecticut to examine the effects of precommercial crop tree release on bole and crown growth. Each study area has 27 8x8 m plots centered on a northern red oak, black oak, or scarlet oak identified as a potential crop-tree (PCT). The 27 plots at each study area were divided into 3 treatments: no cutting, removal of all...

Growth maximization trumps maintenance of leaf conductance in the tallest angiosperm.

PubMed

Koch, George W; Sillett, Stephen C; Antoine, Marie E; Williams, Cameron B

2015-02-01

Structural and physiological changes that occur as trees grow taller are associated with increased hydraulic constraints on leaf gas exchange, yet it is unclear if leaf-level constraints influence whole-tree growth as trees approach their maximum size. We examined variation in leaf physiology, leaf area to sapwood area ratio (L/S), and annual aboveground growth across a range of tree heights in Eucalyptus regnans. Leaf photosynthetic capacity did not differ among upper crown leaves of individuals 61.1-92.4 m tall. Maximum daily and integrated diurnal stomatal conductance (g s) averaged 36 and 34% higher, respectively, in upper crown leaves of ~60-m-tall, 80-year-old trees than in ~90-m-tall, 300-year-old trees, with larger differences observed on days with a high vapor pressure deficit (VPD). Greater stomatal regulation in taller trees resulted in similar minimum daily leaf water potentials (Ψ L) in shorter and taller trees over a broad range of VPDs. The long-term stomatal limitation on photosynthesis, as inferred from leaf δ (13)C composition, was also greater in taller trees. The δ (13)C of wood indicated that the bulk of photosynthesis used to fuel wood production in the main trunk and branches occurred in the upper crown. L/S increased with tree height, especially after accounting for size-independent variation in crown structure across 27 trees up to 99.8 m tall. Despite greater stomatal limitation of leaf photosynthesis in taller trees, total L explained 95% of the variation in annual aboveground biomass growth among 15 trees measured for annual biomass growth increment in 2006. Our results support a theoretical model proposing that, in the face of increasing hydraulic constraints with height, whole-tree growth is maximized by a resource trade-off that increases L to maximize light capture rather than by reducing L/S to sustain g s.

Resistance of full veneer metal crowns with different forms of axial grooves

NASA Astrophysics Data System (ADS)

Hidayat, A. S.; Masulili, C.; Indrasari, M.

2017-08-01

Dental crowns or bridges can occasionally come loose or separate from the tooth during chewing, particularly when they are situated on small, short, and conical teeth. The main cause of this separation is a lack of retention and resistance to the tooth. There are several methods available to increase the retention and resistance of the crown during both inlay and onlay preparation, including parallelism, groove preparation, crown build-up, and surface roughness. The aim of this study was to determine the differences in resistance of full veneer metal crowns with various forms of groove preparation. The study involved the compressive strength testing of a total of 24 specimens, namely six specimens without groove preparation, six specimens with box-shaped grooves, six specimens with V-shaped grooves, and six specimens with half round grooves. The mean values of the metal crowns that separated from the teeth during testing were 27.97 ± 1.08 kgF for the crowns with box-shaped grooves, 6.15 ± 0.22 kgF for those with V-shaped grooves, 1.77 ± 0.12 kgF for those with half round grooves, and 0.95 ± 0.13 kgF for those without grooves. This study found that the resistance is best in crowns with box-shaped grooves, followed by those with V-shaped grooves, half round grooves, and those without groove. When clinicians are working on short and conical molar teeth, it is therefore recommended that box-shaped grooves are used to increase the resistance of the crown.

Generalized and synthetic regression estimators for randomized branch sampling

Treesearch

David L. R. Affleck; Timothy G. Gregoire

2015-01-01

In felled-tree studies, ratio and regression estimators are commonly used to convert more readily measured branch characteristics to dry crown mass estimates. In some cases, data from multiple trees are pooled to form these estimates. This research evaluates the utility of both tactics in the estimation of crown biomass following randomized branch sampling (...

Comparison of Growth Efficiency of Mature Longleaf and Slash Pine Trees

Treesearch

Steven B. Jack; Mary Carol P. Sheffield; Daniel J. McConville

2002-01-01

Variation in aboveground biomass partitioning (between the stem, branches, and foliage) of mature trees is a key determinant of growth potential. Investment of photosynthate in crown components generally results in greater overall biomass production of longer duration. The increased production of crown components may be an investment in longterm aboveground production...

Forest Health Monitoring in Vermont, 1996-1999

Treesearch

Northeastern Research Station

2002-01-01

Vermont forests vary in size and age class. Trees are distributed evenly between hardwood and softwood species but hardwood dominated the seedling sample. Most of the trees are healthy, with full crowns (low transparency, high density), little dieback and little damage. White and green ash had higher transparencies and lower crown densities possibly explained by the...

Crown profile equations for stand-grown western hemlock trees in northwestern Oregon.

Treesearch

David D. Marshall; Gregory P. Johnson; David W. Hann

2003-01-01

Crown profile equations were developed for stand-grown western hemlock(Tsuga heterophylla (Raf.) Sarg.) in northwest Oregon. The profile model uses a segmented approach, dividing the crown into an upper and lower portion at the point of the largest crown width (LCW). The model explains about 86% of the variation in crown width when LCW is known but...

Estimating forest crown area removed by selection cutting: a linked regression-GIS approach based on stump diameters

USGS Publications Warehouse

Anderson, S.C.; Kupfer, J.A.; Wilson, R.R.; Cooper, R.J.

2000-01-01

The purpose of this research was to develop a model that could be used to provide a spatial representation of uneven-aged silvicultural treatments on forest crown area. We began by developing species-specific linear regression equations relating tree DBH to crown area for eight bottomland tree species at White River National Wildlife Refuge, Arkansas, USA. The relationships were highly significant for all species, with coefficients of determination (r(2)) ranging from 0.37 for Ulmus crassifolia to nearly 0.80 for Quercus nuttalliii and Taxodium distichum. We next located and measured the diameters of more than 4000 stumps from a single tree-group selection timber harvest. Stump locations were recorded with respect to an established gl id point system and entered into a Geographic Information System (ARC/INFO). The area occupied by the crown of each logged individual was then estimated by using the stump dimensions (adjusted to DBHs) and the regression equations relating tree DBH to crown area. Our model projected that the selection cuts removed roughly 300 m(2) of basal area from the logged sites resulting in the loss of approximate to 55 000 m(2) of crown area. The model developed in this research represents a tool that can be used in conjunction with remote sensing applications to assist in forest inventory and management, as well as to estimate the impacts of selective timber harvest on wildlife.

Annual and spatial variation in shoot demography associated with masting in Betula grossa: comparison between mature trees and saplings

PubMed Central

Ishihara, Masae Iwamoto; Kikuzawa, Kihachiro

2009-01-01

Backgrounds and Aims Shoot demography affects the growth of the tree crown and the number of leaves on a tree. Masting may cause inter-annual and spatial variation in shoot demography of mature trees, which may in turn affect the resource budget of the tree. The aim of this study was to evaluate the effect of masting on the temporal and spatial variations in shoot demography of mature Betula grossa. Methods The shoot demography was analysed in the upper and lower parts of the tree crown in mature trees and saplings over 7 years. Mature trees and saplings were compared to differentiate the effect of masting from the effect of exogenous environment on shoot demography. The fate of different shoot types (reproductive, vegetative, short, long), shoot length and leaf area were investigated by monitoring and by retrospective survey using morphological markers on branches. The effects of year and branch position on demographic parameters were evaluated. Key Results Shoot increase rate, production of long shoots, bud mortality, length of long shoots and leaf area of a branch fluctuated periodically from year to year in mature trees over 7 years, in which two masting events occurred. Branches within a crown showed synchronized annual variation, and the extent of fluctuation was larger in the upper branches than the lower branches. Vegetative shoots varied in their bud differentiation each year and contributed to the dynamic shoot demography as much as did reproductive shoots, suggesting physiological integration in shoot demography through hormonal regulation and resource allocation. Conclusions Masting caused periodic annual variation in shoot demography of the mature trees and the effect was spatially variable within a tree crown. Since masting is a common phenomenon among tree species, annual variation in shoot demography and leaf area should be incorporated into resource allocation models of mature masting trees. PMID:19734164

Light-dependent leaf trait variation in 43 tropical dry forest tree species.

PubMed

Markesteijn, Lars; Poorter, Lourens; Bongers, Frans

2007-04-01

Our understanding of leaf acclimation in relation to irradiance of fully grown or juvenile trees is mainly based on research involving tropical wet forest species. We studied sun-shade plasticity of 24 leaf traits of 43 tree species in a Bolivian dry deciduous forest. Sampling was confined to small trees. For each species, leaves were taken from five of the most and five of the least illuminated crowns. Trees were selected based on the percentage of the hemisphere uncovered by other crowns. We examined leaf trait variation and the relation between trait plasticity and light demand, maximum adult stature, and ontogenetic changes in crown exposure of the species. Leaf trait variation was mainly related to differences among species and to a minor extent to differences in light availability. Traits related to the palisade layer, thickness of the outer cell wall, and N(area) and P(area) had the greatest plasticity, suggesting their importance for leaf function in different light environments. Short-lived pioneers had the highest trait plasticity. Overall plasticity was modest and rarely associated with juvenile light requirements, adult stature, or ontogenetic changes in crown exposure. Dry forest tree species had a lower light-related plasticity than wet forest species, probably because wet forests cast deeper shade. In dry forests light availability may be less limiting, and low water availability may constrain leaf trait plasticity in response to irradiance.

Assessing and Correcting Topographic Effects on Forest Canopy Height Retrieval Using Airborne LiDAR Data

PubMed Central

Duan, Zhugeng; Zhao, Dan; Zeng, Yuan; Zhao, Yujin; Wu, Bingfang; Zhu, Jianjun

2015-01-01

Topography affects forest canopy height retrieval based on airborne Light Detection and Ranging (LiDAR) data a lot. This paper proposes a method for correcting deviations caused by topography based on individual tree crown segmentation. The point cloud of an individual tree was extracted according to crown boundaries of isolated individual trees from digital orthophoto maps (DOMs). Normalized canopy height was calculated by subtracting the elevation of centres of gravity from the elevation of point cloud. First, individual tree crown boundaries are obtained by carrying out segmentation on the DOM. Second, point clouds of the individual trees are extracted based on the boundaries. Third, precise DEM is derived from the point cloud which is classified by a multi-scale curvature classification algorithm. Finally, a height weighted correction method is applied to correct the topological effects. The method is applied to LiDAR data acquired in South China, and its effectiveness is tested using 41 field survey plots. The results show that the terrain impacts the canopy height of individual trees in that the downslope side of the tree trunk is elevated and the upslope side is depressed. This further affects the extraction of the location and crown of individual trees. A strong correlation was detected between the slope gradient and the proportions of returns with height differences more than 0.3, 0.5 and 0.8 m in the total returns, with coefficient of determination R2 of 0.83, 0.76, and 0.60 (n = 41), respectively. PMID:26016907

Evaluation of wild juglans species for crown gall resistance

USDA-ARS?s Scientific Manuscript database

A. tumefaciens is a soil-borne Gram-negative bacterium which causes crown gall on many dicotyledonous plant species including walnut. Crown gall symptoms on walnut are characterized by large tumors located near the crown of the tree but can occur near wounds caused by bleeding cuts or at the graft u...

Uniform versus Asymmetric Shading Mediates Crown Recession in Conifers

PubMed Central

Schoonmaker, Amanda L.; Lieffers, Victor J.; Landhäusser, Simon M.

2014-01-01

In this study we explore the impact of asymmetrical vs. uniform crown shading on the mortality and growth of upper and lower branches within tree crowns, for two conifer species: shade intolerant lodgepole pine (Pinus contorta) and shade tolerant white spruce (Picea glauca). We also explore xylem hydraulics, foliar nutrition, and carbohydrate status as drivers for growth and expansion of the lower and upper branches in various types of shading. This study was conducted over a two-year period across 10 regenerating forest sites dominated by lodgepole pine and white spruce, in the lower foothills of Alberta, Canada. Trees were assigned to one of four shading treatments: (1), complete uniform shading of the entire tree, (2) light asymmetric shading where the lower 1/4–1/3 of the tree crown was shaded, (3) heavy asymmetric shading as in (2) except with greater light reduction and (4) control in which no artificial shading occurred and most of the entire crown was exposed to full light. Asymmetrical shading of only the lower crown had a larger negative impact on the bud expansion and growth than did uniform shading, and the effect was stronger in pine relative to spruce. In addition, lower branches in pine also had lower carbon reserves, and reduced xylem-area specific conductivity compared to spruce. For both species, but particularly the pine, the needles of lower branches tended to store less C than upper branches in the asymmetric shade, which could suggest a movement of reserves away from the lower branches. The implications of these findings correspond with the inherent shade tolerance and self-pruning behavior of these conifers and supports a carbon based mechanism for branch mortality – mediated by an asymmetry in light exposure of the crown. PMID:25136823

Uniform versus asymmetric shading mediates crown recession in conifers.

PubMed

Schoonmaker, Amanda L; Lieffers, Victor J; Landhäusser, Simon M

2014-01-01

In this study we explore the impact of asymmetrical vs. uniform crown shading on the mortality and growth of upper and lower branches within tree crowns, for two conifer species: shade intolerant lodgepole pine (Pinus contorta) and shade tolerant white spruce (Picea glauca). We also explore xylem hydraulics, foliar nutrition, and carbohydrate status as drivers for growth and expansion of the lower and upper branches in various types of shading. This study was conducted over a two-year period across 10 regenerating forest sites dominated by lodgepole pine and white spruce, in the lower foothills of Alberta, Canada. Trees were assigned to one of four shading treatments: (1), complete uniform shading of the entire tree, (2) light asymmetric shading where the lower 1/4-1/3 of the tree crown was shaded, (3) heavy asymmetric shading as in (2) except with greater light reduction and (4) control in which no artificial shading occurred and most of the entire crown was exposed to full light. Asymmetrical shading of only the lower crown had a larger negative impact on the bud expansion and growth than did uniform shading, and the effect was stronger in pine relative to spruce. In addition, lower branches in pine also had lower carbon reserves, and reduced xylem-area specific conductivity compared to spruce. For both species, but particularly the pine, the needles of lower branches tended to store less C than upper branches in the asymmetric shade, which could suggest a movement of reserves away from the lower branches. The implications of these findings correspond with the inherent shade tolerance and self-pruning behavior of these conifers and supports a carbon based mechanism for branch mortality--mediated by an asymmetry in light exposure of the crown.

Stratifying photo plots into volume classes...by crown closure comparator

Treesearch

Robert C. Aldrich

1967-01-01

As an aid to aerial photo interpretation, a Crown Closure Comparator has been developed. Printed as a positive film transparency, this device shows tree crowns as open dots on a black background. The Comparator is used to stratify I-acre plots into broad volume classes on single aerial photos using 4 crown-diameter and 9 crown-closure classes. It can also be used for...

A numerical rating system for crown classes of southern hardwoods

Treesearch

James S. Meadows; E.C. Burkhardt; Robert L. Johnson; John D. Hodges

2001-01-01

A numerical rating system to delineate crown classes of southern hardwoods is described. The system is based on four criteria: (1) amount of direct sunlight from above, (2) amount of direct sunlight from the sides, (3) crown balance, and (4) relative crown size. The total point value assigned places the tree within one of the four crown classes. The rating system can...

Estimating leaf area and leaf biomass of open-grown deciduous urban trees

Treesearch

David J. Nowak

1996-01-01

Logarithmic regression equations were developed to predict leaf area and leaf biomass for open-grown deciduous urban trees based on stem diameter and crown parameters. Equations based on crown parameters produced more reliable estimates. The equations can be used to help quantify forest structure and functions, particularly in urbanizing and urban/suburban areas.

Multiseasonal Tree Crown Structure Mapping with Point Clouds from OTS Quadrocopter Systems

NASA Astrophysics Data System (ADS)

Hese, S.; Behrendt, F.

2017-08-01

OTF (Off The Shelf) quadro copter systems provide a cost effective (below 2000 Euro), flexible and mobile platform for high resolution point cloud mapping. Various studies showed the full potential of these small and flexible platforms. Especially in very tight and complex 3D environments the automatic obstacle avoidance, low copter weight, long flight times and precise maneuvering are important advantages of these small OTS systems in comparison with larger octocopter systems. This study examines the potential of the DJI Phantom 4 pro series and the Phantom 3A series for within-stand and forest tree crown 3D point cloud mapping using both within stand oblique imaging in different altitude levels and data captured from a nadir perspective. On a test site in Brandenburg/Germany a beach crown was selected and measured with 3 different altitude levels in Point Of Interest (POI) mode with oblique data capturing and deriving one nadir mosaic created with 85/85 % overlap using Drone Deploy automatic mapping software. Three different flight campaigns were performed, one in September 2016 (leaf-on), one in March 2017 (leaf-off) and one in May 2017 (leaf-on) to derive point clouds from different crown structure and phenological situations - covering the leaf-on and leafoff status of the tree crown. After height correction, the point clouds where used with GPS geo referencing to calculate voxel based densities on 50 × 10 × 10 cm voxel definitions using a topological network of chessboard image objects in 0,5 m height steps in an object based image processing environment. Comparison between leaf-off and leaf-on status was done on volume pixel definitions comparing the attributed point densities per volume and plotting the resulting values as a function of distance to the crown center. In the leaf-off status SFM (structure from motion) algorithms clearly identified the central stem and also secondary branch systems. While the penetration into the crown structure is limited in the leaf-on status (the point cloud is a mainly a description of the interpolated crown surface) - the visibility of the internal crown structure in leaf-off status allows to map also the internal tree structure up to and stopping at the secondary branch level system. When combined the leaf-on and leaf-off point clouds generate a comprehensive tree crown structure description that allows a low cost and detailed 3D crown structure mapping and potentially precise biomass mapping and/or internal structural differentiation of deciduous tree species types. Compared to TLS (Terrestrial Laser Scanning) based measurements the costs are neglectable and in the range of 1500-2500 €. This suggests the approach for low cost but fine scale in-situ applications and/or projects where TLS measurements cannot be derived and for less dense forest stands where POI flights can be performed. This study used the in-copter GPS measurements for geo referencing. Better absolute geo referencing results will be obtained with DGPS reference points. The study however clearly demonstrates the potential of OTS very low cost copter systems and the image attributed GPS measurements of the copter for the automatic calculation of complex 3D point clouds in a multi temporal tree crown mapping context.

Tree crown structural characterization: A study using terrestrial laser scanning and three-dimensional radiative transfer modeling

NASA Astrophysics Data System (ADS)

Moorthy, Inian

Spectroscopic observational data for vegetated environments, have been coupled with 3D physically-based radiative transfer models for retrievals of biochemical and biophysical indicators of vegetation health and condition. With the recent introduction of Terrestrial Laser Scanning (TLS) units, there now exists a means of rapidly measuring intricate structural details of vegetation canopies, which can also serve as input into 3D radiative transfer models. In this investigation, Intelligent Laser Ranging and Imaging System (ILRIS-3D) data was acquired of individual tree crowns in laboratory, and field-based experiments. The ILRIS-3D uses the Time-Of-Flight (TOF) principle to measure the distances of objects based on the time interval between laser pulse exitance and return, upon reflection from an object. At the laboratory-level, this exploratory study demonstrated and validated innovative approaches for retrieving crown-level estimates of Leaf Area Index (LAI) (r2 = 0.98, rmse = 0.26m2/m2), a critical biophysical parameter for vegetation monitoring and modeling. These methods were implemented and expanded in field experiments conducted in olive (Olea europaea L.) orchards in Cordoba, Spain, where ILRIS-3D observations for 24 structurally-variable trees were made. Robust methodologies were developed to characterize diagnostic architectural parameters, such as tree height (r2 = 0.97, rmse = 0.21m), crown width (r 2 = 0.98, rmse = 0.12m), crown height (r2 = 0.81, rmse = 0.11m), crown volume (r2 = 0.99, rmse = 2.6m3), and LAI (r2 = 0.76, rmse = 0.27m2/ m2). These parameters were subsequently used as direct inputs into the Forest LIGHT (FLIGHT) 3D ray tracing model for characterization of the spectral behavior of the olive crowns. Comparisons between FLIGHT-simulated spectra and measured data showed small differences in the visible (< 3%) and near infrared (< 10%) spectral ranges. These differences between model simulations and measurements were significantly correlated to TLS-derived tree crown complexity metrics. The specific implications of internal crown complexity on estimating leaf chlorophyll concentration, a pertinent physiological health indicator, is highlighted. This research demonstrates that TLS systems can potentially be the new observational tool and benchmark for precise characterization of vegetation architecture for synergy with 3D radiative transfer models for improved operational management of agricultural crops.

Unearthing the hidden world of roots: Root biomass and architecture differ among species within the same guild

PubMed Central

2017-01-01

The potential benefits of planting trees have generated significant interest with respect to sequestering carbon and restoring other forest based ecosystem services. Reliable estimates of carbon stocks are pivotal for understanding the global carbon balance and for promoting initiatives to mitigate CO2 emissions through forest management. There are numerous studies employing allometric regression models that convert inventory into aboveground biomass (AGB) and carbon (C). Yet the majority of allometric regression models do not consider the root system nor do these equations provide detail on the architecture and shape of different species. The root system is a vital piece toward understanding the hidden form and function roots play in carbon accumulation, nutrient and plant water uptake, and groundwater infiltration. Work that estimates C in forests as well as models that are used to better understand the hydrologic function of trees need better characterization of tree roots. We harvested 40 trees of six different species, including their roots down to 2 mm in diameter and created species-specific and multi-species models to calculate aboveground (AGB), coarse root belowground biomass (BGB), and total biomass (TB). We also explore the relationship between crown structure and root structure. We found that BGB contributes ~27.6% of a tree’s TB, lateral roots extend over 1.25 times the distance of crown extent, root allocation patterns varied among species, and that AGB is a strong predictor of TB. These findings highlight the potential importance of including the root system in C estimates and lend important insights into the function roots play in water cycling. PMID:29023553

Tree regeneration in black ash (Fraxinus nigra) stands exhibiting crown dieback in Minnesota

Treesearch

Brian J. Palik; Michael E. Ostry; Robert C. Venette; Ebrahim. Abdela

2012-01-01

Crown dieback and mortality of black ash (Fraxinus nigra) has been noted across the range of the species in North America for several decades. Causes of dieback and mortality are not definitive, but may be related to spring drought or excessive moisture. Where black ash is the dominant tree species in the forest, continued dieback and mortality may...

Impact of competitor species composition on predicting diameter growth and survival rates of Douglas-fir trees in southwestern Oregon

USGS Publications Warehouse

Bravo, Felipe; Hann, D.W.; Maguire, Douglas A.

2001-01-01

Mixed conifer and hardwood stands in southwestern Oregon were studied to explore the hypothesis that competition effects on individual-tree growth and survival will differ according to the species comprising the competition measure. Likewise, it was hypothesized that competition measures should extrapolate best if crown-based surrogates are given preference over diameter-based (basal area based) surrogates. Diameter growth and probability of survival were modeled for individual Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees growing in pure stands. Alternative models expressing one-sided and two-sided competition as a function of either basal area or crown structure were then applied to other plots in which Douglas-fir was mixed with other conifers and (or) hardwood species. Crown-based variables outperformed basal area based variables as surrogates for one-sided competition in both diameter growth and survival probability, regardless of species composition. In contrast, two-sided competition was best represented by total basal area of competing trees. Surrogates reflecting differences in crown morphology among species relate more closely to the mechanics of competition for light and, hence, facilitate extrapolation to species combinations for which no observations are available.

[Effect of greenbelt on pollutant dispersion in street canyon].

PubMed

Xu, Wei-Jia; Xing, Hong; Yu, Zhi

2012-02-01

The effect feature of greenbelt on flow field and pollutant dispersion in urban street canyon was researched. The greenbelt was assumed as uniform porous media and its aerodynamics property defined by the pressure loss coefficient. Subsequently, the pollutant dispersion in the street canyon of which there was greenbelt in the middle was simulated with the steady-state standard kappa-epsilon turbulence model and species transport equation. The simulated results agreed well with the wind-tunnel data. Compared with the treeless case, it finds that the street canyon contain a clockwise vortex, the pollutant concentration of the leeward was several times than the windward and the growth rate of pollutant concentration was 46.0%. The further simulation for the impact of tree crown position on the airflow and pollutant dispersion finds that the height of major vortex center in the street canyon increases with the height of tree crown and gradually closes the top of windward building This causes that the average wind speed in the street canyon decreases. Especially when the top of tree crown over the roof and hinder the air flow above the street canyon, the average pollutant concentration increases with the height of tree crown rapidly.

Detecting Forests Damaged by Pine Wilt Disease at the Individual Tree Level Using Airborne Laser Data and WORLDVIEW-2/3 Images Over Two Seasons

NASA Astrophysics Data System (ADS)

Takenaka, Y.; Katoh, M.; Deng, S.; Cheung, K.

2017-10-01

Pine wilt disease is caused by the pine wood nematode (Bursaphelenchus xylophilus) and Japanese pine sawyer (Monochamus alternatus). This study attempted to detect damaged pine trees at different levels using a combination of airborne laser scanning (ALS) data and high-resolution space-borne images. A canopy height model with a resolution of 50 cm derived from the ALS data was used for the delineation of tree crowns using the Individual Tree Detection method. Two pan-sharpened images were established using the ortho-rectified images. Next, we analyzed two kinds of intensity-hue-saturation (IHS) images and 18 remote sensing indices (RSI) derived from the pan-sharpened images. The mean and standard deviation of the 2 IHS images, 18 RSI, and 8 bands of the WV-2 and WV-3 images were extracted for each tree crown and were used to classify tree crowns using a support vector machine classifier. Individual tree crowns were assigned to one of nine classes: bare ground, Larix kaempferi, Cryptomeria japonica, Chamaecyparis obtusa, broadleaved trees, healthy pines, and damaged pines at slight, moderate, and heavy levels. The accuracy of the classifications using the WV-2 images ranged from 76.5 to 99.6 %, with an overall accuracy of 98.5 %. However, the accuracy of the classifications using the WV-3 images ranged from 40.4 to 95.4 %, with an overall accuracy of 72 %, which suggests poorer accuracy compared to those classes derived from the WV-2 images. This is because the WV-3 images were acquired in October 2016 from an area with low sun, at a low altitude.

Vascular Epiphyte Diversity Differs with Host Crown Zone and Diameter, but Not Orientation in a Tropical Cloud Forest

PubMed Central

Wang, Xixi; Long, Wenxing; Schamp, Brandon S.; Yang, Xiaobo; Kang, Yong; Xie, Zhixu; Xiong, Menghui

2016-01-01

Vascular epiphytes are important components of biological diversity in tropical forests. We measured the species richness and abundance of vascular epiphytes along four vertical crown zones and five horizontal orientations on 376 trees, as well as the diameter at breast height (DBH) of host trees in tropical cloud forests in Bawangling, Hainan, China. The relationship between vascular epiphyte species richness and host tree DBH was assessed using a generalized linear model. There were 1,453 vascular individual epiphytes attributed to 9 families, 24 genera and 35 species, with orchids and pteridophytes dominating. Both the species richness and abundance of epiphytes significantly differed among the four crown zones for all collections and each host tree, suggesting that vertical microhabitats contribute to the distribution of epiphytes on host trees. Neither epiphyte abundance nor species richness differed among the eastern, southern, western, and northern orientations for all host trees; however, both richness and abundance were significantly higher for epiphytes that encircled host tree trunks. This suggests that morphological and physiological characteristics of the tree, but not microclimates probably contribute to the distribution of epiphytes on host trees. Epiphyte species richness was positively correlated with tree DBH across the six host tree species studied, with increases in DBH among smaller trees resulting in larger increases in richness, while increases in DBH among larger host trees resulting in more modest increases in ephiphyte richness. Our findings contribute support for a positive relationship between epiphyte species richness and host tree DBH and provide important guidance for future surveys of epiphyte community development. PMID:27391217

Bud development and shoot morphology in relation to crown location

PubMed Central

Kukk, Maarja; Sõber, Anu

2015-01-01

Plant architecture is shaped by endogenous growth processes interacting with the local environment. The current study investigated crown development in young black alder trees, assessing the effects of local light conditions and branch height on individual bud mass and contents. In addition, we examined the characteristics of parent shoots [the cross-sectional area (CSA) of stem and total leaf area, shoot length, the number of nodes, the number and total mass of buds per shoot] and leaf–stem as well as bud–stem allometry, as several recent studies link bud development to hydraulic architecture. We sampled shoots from top branches and two lower-crown locations: one subjected to deep shade and the other resembling the upper branches in light availability. Sampling was carried out three times between mid-July and late October, spanning from the early stages of bud growth to dormancy. Individual bud mass and shoot characteristics varied in response to light conditions, whereas leaf–stem allometry depended on branch height, most likely compensating for the increasing length of hydraulic pathways. Despite the differences in individual bud mass, the number of preformed leaves varied little across the crown, indicating that the plasticity in shoot characteristics was mainly achieved by neoformation. The relationship between total bud mass and stem CSA scaled similarly across crown locations. However, scaling slopes gradually decreased throughout the sampling period, driven by bud rather than by stem growth. This suggests that the allometry of total bud mass and CSA of stem is regulated locally, instead of resulting from crown-level processes. PMID:26187607

Olive Crown Porosity Measurement Based on Radiation Transmittance: An Assessment of Pruning Effect.

PubMed

Castillo-Ruiz, Francisco J; Castro-Garcia, Sergio; Blanco-Roldan, Gregorio L; Sola-Guirado, Rafael R; Gil-Ribes, Jesus A

2016-05-19

Crown porosity influences radiation interception, air movement through the fruit orchard, spray penetration, and harvesting operation in fruit crops. The aim of the present study was to develop an accurate and reliable methodology based on transmitted radiation measurements to assess the porosity of traditional olive trees under different pruning treatments. Transmitted radiation was employed as an indirect method to measure crown porosity in two olive orchards of the Picual and Hojiblanca cultivars. Additionally, three different pruning treatments were considered to determine if the pruning system influences crown porosity. This study evaluated the accuracy and repeatability of four algorithms in measuring crown porosity under different solar zenith angles. From a 14° to 30° solar zenith angle, the selected algorithm produced an absolute error of less than 5% and a repeatability higher than 0.9. The described method and selected algorithm proved satisfactory in field results, making it possible to measure crown porosity at different solar zenith angles. However, pruning fresh weight did not show any relationship with crown porosity due to the great differences between removed branches. A robust and accurate algorithm was selected for crown porosity measurements in traditional olive trees, making it possible to discern between different pruning treatments.

The effects of planting density and cultural intensity on loblolly pine crown characteristics at age twelve

Treesearch

Madison Akers; Michael Kane; Robert Teskey; Richard Daniels; Dehai Zhao; Santosh Subedi

2012-01-01

Twelve-year old loblolly pine (Pinus taeda L.) stands were analyzed for the effects of planting density and cultural intensity on tree and crown attributes. Four study installations were located in the Piedmont and Upper Coastal Plain regions of the U.S. South. The treatments included six planting densities (740, 1480, 2220, 2960, 3700, 4440 trees...

Postfire survival and flushing in three Sierra Nevada conifers with high initial crown scorch

Treesearch

C. Hanson; M. North

2009-01-01

With growing debate over the impacts of post-fire salvage logging in conifer forests of the western USA, managers need accurate assessments of tree survival when significant proportions of the crown have been scorched. The accuracy of fire severity measurements will be affected if trees that initially appear to be fire-killed prove to be viable after longer observation...

Future directions in forest hydrology

Treesearch

T.M. Williams; Devendra Amatya; L. Bren; C. deJong; J.E. Nettles

2016-01-01

Forest hydrology is a separate and unique branch of hydrology due to the special conditions caused by trees, and the understorey beneath them, comprising a forest. Understanding the forest, with trees that can grow over 100 m tall, may have crowns up to 20-30 m in diameter with roots 5-10 m deep and spread as widely as the crowns, and have lifespans from 50 to 5000...

Five Years' Growth of Pruned and Unpruned Cottonwood Planted at 40- by 40-Foot Spacing

Treesearch

Roger M. Krinard

1979-01-01

Four pruning treatments have been applied for 5 years on cottonwood (Populus deltoides Bartr.) select clone Stoneville 66, planted at 40- by 40-ft spacing. As pruning severity increased, average diameter and maximum crown width decreased. Diameters ranged from 9.2 inches for trees pruned half of height yearly to 11.4 inches for unpruned trees; crown widths ranged from...

Tree survival 15 years after the ice storm of January 1998

Treesearch

Walter C. Shortle; Kevin T. Smith; Kenneth R. Dudzik

2014-01-01

The regional ice storm of early January 1998 was a widespread disturbance for millions of acres of forest in northeastern New York, northern New England, and southern Quebec. Tree crowns were partially or totally lost as stems snapped and branches broke with the weight of the deposited ice. We tracked the effect of crown injury on a large sample of northern hardwood...

An assessment of factors associated with damage to tree crowns from the 1987 wildfires in northern California

Treesearch

C. Phillip Weatherspoon; Carl N. Skinner

1995-01-01

Relationships between (1) degree of damage caused by the 1987 fires in northern California and (2) prior management activities, fuelbed characteristics, and site/stand factors were studied on the Hayfork Ranger District of the Shasta-Trinity National Forests. Postfire aerial photography was used to assess scorch and consumption of tree crowns (the selected measure of...

Response of different-aged black cherry trees to ambient ozone exposure

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

Fredericksen, T.S.; Joyce, B.J.; Kouterick, K.B.

1994-06-01

Black cherry (Prunus serotina Ehrh.) is a valuable commercial timber species which is also highly sensitive to ozone relative to other eastern deciduous tree species. Studies of ozone effects on forest trees have been restricted mostly to experiments using small seedlings under controlled conditions. Yet, mature trees may differ from seedlings in physiology, morphology, and exposure to air pollutants. An experiment was conducted in 1993 to determine differences in ozone uptake and foliar injury symptoms between open-ground seedlings, forest saplings, and mature forest trees of black cherry in northcentral Pennsylvania. Seedlings grew under the highest ozone concentrations and also hadmore » greater seasonal ozone uptake due to higher rates of stomatal conductance. However, because of their indeterminate growth habit, seedlings had lower cumulative ozone uptake per leaf lifespan than saplings or mature trees, both of which had determinate shoot growth. Although greater initially for seedlings, foliar injury was nearly identical between size classes by the end of the growing season. Leaves in the lower crown of larger trees had lower ozone uptake than leaves in the upper crown, but exhibited more foliar injury symptoms. Lower crown leaves received more effective exposure to ozone because of their thinner leaves and had less available photosynthate for repair or replacement of damaged tissue.« less

Evaluation of wild Juglans species for crown gall resistance

USDA-ARS?s Scientific Manuscript database

Paradox, the most widely used rootstock in CA walnut production, is highly susceptible to the causal agent of crown gall (CG) Agrobacterium tumefaciens. The bacterial pathogen induces the formation of large tumors around the crown of the tree resulting in a reduction in both vigor and yield. If left...

Edge-to-Stem Variability in Wet-Canopy Evaporation From an Urban Tree Row

NASA Astrophysics Data System (ADS)

Van Stan, John T.; Norman, Zachary; Meghoo, Adrian; Friesen, Jan; Hildebrandt, Anke; Côté, Jean-François; Underwood, S. Jeffrey; Maldonado, Gustavo

2017-11-01

Evaporation from wet-canopy (E_C) and stem (E_S) surfaces during rainfall represents a significant portion of municipal-to-global scale hydrologic cycles. For urban ecosystems, E_C and E_S dynamics play valuable roles in stormwater management. Despite this, canopy-interception loss studies typically ignore crown-scale variability in E_C and assume (with few indirect data) that E_S is generally {<}2% of total wet-canopy evaporation. We test these common assumptions for the first time with a spatially-distributed network of in-canopy meteorological monitoring and 45 surface temperature sensors in an urban Pinus elliottii tree row to estimate E_C and E_S under the assumption that crown surfaces behave as "wet bulbs". From December 2015 through July 2016, 33 saturated crown periods (195 h of 5-min observations) were isolated from storms for determination of 5-min evaporation rates ranging from negligible to 0.67 mm h^{-1}. Mean E_S (0.10 mm h^{-1}) was significantly lower (p < 0.01) than mean E_C (0.16 mm h^{-1}). But, E_S values often equalled E_C and, when scaled to trunk area using terrestrial lidar, accounted for 8-13% (inter-quartile range) of total wet-crown evaporation (E_S+E_C scaled to surface area). E_S contributions to total wet-crown evaporation maximized at 33%, showing a general underestimate (by 2-17 times) of this quantity in the literature. Moreover, results suggest wet-crown evaporation from urban tree rows can be adequately estimated by simply assuming saturated tree surfaces behave as wet bulbs, avoiding problematic assumptions associated with other physically-based methods.

Operational Tree Species Mapping in a Diverse Tropical Forest with Airborne Imaging Spectroscopy.

PubMed

Baldeck, Claire A; Asner, Gregory P; Martin, Robin E; Anderson, Christopher B; Knapp, David E; Kellner, James R; Wright, S Joseph

2015-01-01

Remote identification and mapping of canopy tree species can contribute valuable information towards our understanding of ecosystem biodiversity and function over large spatial scales. However, the extreme challenges posed by highly diverse, closed-canopy tropical forests have prevented automated remote species mapping of non-flowering tree crowns in these ecosystems. We set out to identify individuals of three focal canopy tree species amongst a diverse background of tree and liana species on Barro Colorado Island, Panama, using airborne imaging spectroscopy data. First, we compared two leading single-class classification methods--binary support vector machine (SVM) and biased SVM--for their performance in identifying pixels of a single focal species. From this comparison we determined that biased SVM was more precise and created a multi-species classification model by combining the three biased SVM models. This model was applied to the imagery to identify pixels belonging to the three focal species and the prediction results were then processed to create a map of focal species crown objects. Crown-level cross-validation of the training data indicated that the multi-species classification model had pixel-level producer's accuracies of 94-97% for the three focal species, and field validation of the predicted crown objects indicated that these had user's accuracies of 94-100%. Our results demonstrate the ability of high spatial and spectral resolution remote sensing to accurately detect non-flowering crowns of focal species within a diverse tropical forest. We attribute the success of our model to recent classification and mapping techniques adapted to species detection in diverse closed-canopy forests, which can pave the way for remote species mapping in a wider variety of ecosystems.

Operational Tree Species Mapping in a Diverse Tropical Forest with Airborne Imaging Spectroscopy

PubMed Central

Baldeck, Claire A.; Asner, Gregory P.; Martin, Robin E.; Anderson, Christopher B.; Knapp, David E.; Kellner, James R.; Wright, S. Joseph

2015-01-01

Remote identification and mapping of canopy tree species can contribute valuable information towards our understanding of ecosystem biodiversity and function over large spatial scales. However, the extreme challenges posed by highly diverse, closed-canopy tropical forests have prevented automated remote species mapping of non-flowering tree crowns in these ecosystems. We set out to identify individuals of three focal canopy tree species amongst a diverse background of tree and liana species on Barro Colorado Island, Panama, using airborne imaging spectroscopy data. First, we compared two leading single-class classification methods—binary support vector machine (SVM) and biased SVM—for their performance in identifying pixels of a single focal species. From this comparison we determined that biased SVM was more precise and created a multi-species classification model by combining the three biased SVM models. This model was applied to the imagery to identify pixels belonging to the three focal species and the prediction results were then processed to create a map of focal species crown objects. Crown-level cross-validation of the training data indicated that the multi-species classification model had pixel-level producer’s accuracies of 94–97% for the three focal species, and field validation of the predicted crown objects indicated that these had user’s accuracies of 94–100%. Our results demonstrate the ability of high spatial and spectral resolution remote sensing to accurately detect non-flowering crowns of focal species within a diverse tropical forest. We attribute the success of our model to recent classification and mapping techniques adapted to species detection in diverse closed-canopy forests, which can pave the way for remote species mapping in a wider variety of ecosystems. PMID:26153693

Estimation of carbon storage based on individual tree detection in Pinus densiflora stands using a fusion of aerial photography and LiDAR data.

PubMed

Kim, So-Ra; Kwak, Doo-Ahn; Lee, Woo-Kyun; oLee, Woo-Kyun; Son, Yowhan; Bae, Sang-Won; Kim, Choonsig; Yoo, Seongjin

2010-07-01

The objective of this study was to estimate the carbon storage capacity of Pinus densiflora stands using remotely sensed data by combining digital aerial photography with light detection and ranging (LiDAR) data. A digital canopy model (DCM), generated from the LiDAR data, was combined with aerial photography for segmenting crowns of individual trees. To eliminate errors in over and under-segmentation, the combined image was smoothed using a Gaussian filtering method. The processed image was then segmented into individual trees using a marker-controlled watershed segmentation method. After measuring the crown area from the segmented individual trees, the individual tree diameter at breast height (DBH) was estimated using a regression function developed from the relationship observed between the field-measured DBH and crown area. The above ground biomass of individual trees could be calculated by an image-derived DBH using a regression function developed by the Korea Forest Research Institute. The carbon storage, based on individual trees, was estimated by simple multiplication using the carbon conversion index (0.5), as suggested in guidelines from the Intergovernmental Panel on Climate Change. The mean carbon storage per individual tree was estimated and then compared with the field-measured value. This study suggested that the biomass and carbon storage in a large forest area can be effectively estimated using aerial photographs and LiDAR data.

New perspectives on the ecology of tree structure and tree communities through terrestrial laser scanning.

PubMed

Malhi, Yadvinder; Jackson, Tobias; Patrick Bentley, Lisa; Lau, Alvaro; Shenkin, Alexander; Herold, Martin; Calders, Kim; Bartholomeus, Harm; Disney, Mathias I

2018-04-06

Terrestrial laser scanning (TLS) opens up the possibility of describing the three-dimensional structures of trees in natural environments with unprecedented detail and accuracy. It is already being extensively applied to describe how ecosystem biomass and structure vary between sites, but can also facilitate major advances in developing and testing mechanistic theories of tree form and forest structure, thereby enabling us to understand why trees and forests have the biomass and three-dimensional structure they do. Here we focus on the ecological challenges and benefits of understanding tree form, and highlight some advances related to capturing and describing tree shape that are becoming possible with the advent of TLS. We present examples of ongoing work that applies, or could potentially apply, new TLS measurements to better understand the constraints on optimization of tree form. Theories of resource distribution networks, such as metabolic scaling theory, can be tested and further refined. TLS can also provide new approaches to the scaling of woody surface area and crown area, and thereby better quantify the metabolism of trees. Finally, we demonstrate how we can develop a more mechanistic understanding of the effects of avoidance of wind risk on tree form and maximum size. Over the next few years, TLS promises to deliver both major empirical and conceptual advances in the quantitative understanding of trees and tree-dominated ecosystems, leading to advances in understanding the ecology of why trees and ecosystems look and grow the way they do.

Modelling available crown fuel for Pinus pinaster Ait. stands in the "Cazorla, Segura and Las Villas Natural Park" (Spain).

PubMed

Molina, Juan Ramón; Rodríguez y Silva, Francisco; Mérida, Enrique; Herrera, Miguel Ángel

2014-11-01

One of the main limiting aspects in the application of crown fire models at landscape scale has been the uncertainty derived to describe canopy fuel stratum. Available crown fuel and canopy bulk density are essential in order to simulate crown fire behaviour and are of potential use in the evaluation of silvicultural treatments. Currently, the more accurate approach to estimate these parameters is to develop allometric models from common stand inventory data. In this sense, maritime pine (Pinus pinaster Aiton) trees were destructively sampled in the South of the Iberian Peninsula, covering natural and artificial stands. Crown fine fuel was separated into size classes and allometric equations that estimate crown fuel load by biomass fractions were developed. Available crown fuel was determined according to the fuel load differences between un-burned and burned trees with similar characteristics. Taking our destructive post-fire inventory into account, available crown fuel was estimated as the sum of needles biomass, 87.63% of the twigs biomass and 62.79% of the fine branches biomass. In spite of the differences between natural and artificial stands, generic models explained 82% (needles biomass), 89% (crown fuel), 92% (available crown fuel) and 94% (canopy bulk density) of the observed variation. Inclusion of the fitted models in fire management decision-making can provide a decision support system for assessing the potential crown fire of different silvicultural alternatives. Copyright © 2014 Elsevier Ltd. All rights reserved.

Insect Infestations Linked to Shifts in Microclimate: Important Climate Change Implications

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

Classen, Aimee T; Hart, Stephen C; Whitham, Thomas G

Changes in vegetation due to drought-influenced herbivory may influence microclimate in ecosystems. In combination with studies of insect resistant and susceptible trees, we used long-term herbivore removal experiments with two herbivores of pinon (Pinus edulis Endelm.) to test the general hypothesis that herbivore alteration of plant architecture affects soil microclimate, a major driver of ecosystem-level processes. The pinon needle scale (Matsucoccus acalyptus, Herbert) attacks needles of juvenile trees causing them to develop an open crown. In contrast, the stem-boring moth (Dioryctria albovittella Hulst.) kills the terminal shoots of mature trees, causing the crown to develop a dense form. Our studiesmore » focused on how the microclimate effects of these architectural changes are likely to accumulate over time. Three patterns emerged: (1) scale herbivory reduced leaf area index (LAI) of susceptible trees by 39%, whereas moths had no effect on LAI; (2) scale herbivory increased soil moisture and temperature beneath susceptible trees by 35 and 26%, respectively, whereas moths had no effect; and (3) scale and moth herbivory decreased crown interception of precipitation by 51 and 29%, respectively. From these results, we conclude: (1) the magnitude of scale effects on soil moisture and temperature is large, similar to global change scenarios, and sufficient to drive changes in ecosystem processes. (2) The larger sizes of moth-susceptible trees apparently buffered them from most microclimate effects of herbivory, despite marked changes in crown architecture. (3) The phenotypic expression of susceptibility or resistance to scale insects extends beyond plant-herbivore interactions to the physical environment.« less

Growth trends in pruned red spruce trees

Treesearch

Barton M. Blum; Dale S. Solomon

1980-01-01

The diameter growth of red spruce with 1/6, 1/3, and 1/2 crown removed was compared with that of unpruned trees for 18 growing seasons. Although removal of 1/6 of the live crown did not adversely affect annual radial growth, compared with that of the controls, removal of 1/3 and 1/2 had a significant effect on the cumulative radial growth for 2 and 9 growing seasons,...

Numerical simulation of crown fire hazard following bark beetle-caused mortality in lodgepole pine forests

Treesearch

Chad Hoffman; Russell Parsons; Penny Morgan; Ruddy Mell

2010-01-01

The purpose of this study is to investigate how varying amounts of MPB-induced tree mortality affects the amount of crown fuels consumed and the fire intensity across a range of lodgepole pine stands of different tree density and spatial arrangements during the early stages of a bark beetle outbreak. Unlike past studies which have relied on semi-empirical or empirical...

The potential of using coppice growth as training trees in plantations for the production of high-quality oak boles

Treesearch

Wayne K. Clatterbuck

2016-01-01

Oaks (Quercus spp.) grown in monoculture plantations often do not develop high-grade boles because all the trees grow at similar rates and crown stratification does not occur resulting in persistent branches and poor bole quality. The use of trainer species in mixed species plantations could promote interspecific competition and crown...

Different Response of Sap Flow at Different Measurement Depths after Thinning in a Japanese Cypress Plantation

NASA Astrophysics Data System (ADS)

Chiu, C. W.; Gomi, T.; Onda, Y.; Kato, H.; Sakashita, W.; Sun, X.

2017-12-01

Thinning experiments in forests can alter light conditions and further affect growth rate and transpiration of the remained trees. Previous studies suggested transpiration was increased one year after thinning experiment due to improved canopy light condition. On the other hand, the anatomical and morphological responses to thinning are not react immediately because of the tree adaptation to the new surrounding conditions. It has been hypothesized that lower crown is connected to the inner part of sapwood and need more years to adapt new light conditions after thinning. However, our knowledge for the relationship between tree crown development and water movement inside the trunk after several years from thinning experiment was still limited due to lack of long-term field measurement after thinning. Therefore, in this study, we aim to examine the interannual variability of water movement inside the trunk accompanied the development of tree crown after thinning experiment. To do that, we applied sap flow measurement and terrestrial LiDAR survey from 2011 to 2017 in a Japanese cypress (Chamaecyparis obtusa) plantation in Japan, where 50% strip thinning experiment was conducted in the end of 2011. Consequently, we found sap flow densities at different measurement depths were not always increased year by year and those may relate to the crown development after thinning.

Distribution of Lepidopteran Larvae on Norway Spruce: Effects of Slope and Crown Aspect.

PubMed

Kulfan, Ján; Dvořáčková, Katarína; Zach, Peter; Parák, Michal; Svitok, Marek

2016-04-01

Lepidoptera associated with Norway spruce, Picea abies (L.) Karsten, play important roles in ecosystem processes, acting as plant pests, prey for predators, and hosts for parasites and parasitoids. Their distribution patterns in spruce crowns and forests are only poorly understood. We examined how slope and crown aspect affect the occurrence and abundance of moth larvae on solitary spruce trees in a montane region in Central Europe. Moth larvae were collected from southern and northern crowns of trees growing on south- and north-facing slopes (four treatments) using emergence boxes at the end of winter and by the beating method during the growing season. Species responses to slope and crown aspect were not uniform. Treatment effects on moth larvae were stronger in the winter than during the growing season. In winter, the abundance of bud-boring larvae was significantly higher in northern than in southern crowns regardless of the slope aspect, while both slope and aspect had marginally significant effects on abundance of miners. During the growing season, the occurrence of free-living larvae was similar among treatments. Emergence boxes and beating spruce branches are complementary techniques providing valuable insights into the assemblage structure of moth larvae on Norway spruce. Due to the uneven distribution of larvae detected in this study, we recommend adoption of a protocol that explicitly includes sampling of trees from contrasting slopes and branches from contrasting crown aspect in all seasons. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Tree Diametric Increment and Litterfall Production in an Eastern Amazonian Forest: the Role of Functional Groups

NASA Astrophysics Data System (ADS)

Camargo, P. B. D.; Ferreira, M. L.; Oliveira Junior, R. C.; Saleska, S. R.

2014-12-01

Tree growth is a biotic variable of great importance in understanding the dynamics of tree communities and may be used as a tool in studies of biological or climate modeling. Some climate models predict more recurrent climate anomalies in this century, which may alter the functioning of tropical forests with serious structural and demographic implications. The present study aimed to evaluate the profile of tree growth and litterfall production in an eastern Amazon forest, which has suffered recent climatic disturbances. We contrasted different functional groups based on wood density (stem with 0.55; 0.56-0.7; >0.7 g cm-3), light availability (crown illumination index; high illuminated crown - IIC1 until shaded crown - IIC5), and, size class (trees 10-22.5; 22.6-35; 35.1-55; 55,1-90; >90 cm dbh). Tree diameter increment was monthly measured from November 2011 to September 2013 by using dendrometer bands installed on 850 individuals from different families. Litterfall was collected in 64 circular traps, oven dried and weighed, separated into leaves, twigs, reproductive parts and miscellaneous. During the rainy season the sampled trees had the highest rates of tree diametric increment. When analyzing the data by functional groups, large trees had faster growth, but when grouped by wood density, trees with wood density up to 0.55 and between 0.56 and 0.7 g cm-3 had the fastest rates of growth. When grouped by crown illumination index, trees exposed to higher levels of light grew more in comparison to partially shaded trees. Maximum daily air temperature and precipitation were the most important environmental variables in determining the diametric increment profile of the trees. Litterfall production was estimated to be 7.1 Mg ha-1.year-1 and showed a strong seasonal pattern, with dry season production being higher than in the rainy season. Leaves formed the largest fraction of the litterfall, followed by twigs, reproductive parts, and finally miscellaneous. These results show that the profile of tree diametric growth and litterfall production are recorded at close intervals in the preterit analyzes in the same study area and highlights the efficiency of functional groups in determining the tree growth profile.

The woody biomass resource of major tree taxa for the Midsouth States

Treesearch

James F. Rosson

1992-01-01

Fresh and dry biomass estimates of major trees in seven Midsouth States by forest type, ownership, species, stand basal area, tree class, diameter, and height are tabulated. Information is presented for total tree, bole, and crown components.

The woody biomass resource of Tennessee, 1989

Treesearch

James F. Rosson

1993-01-01

Tabulates fresh and dry biomass estimates of major trees in Tennessee by forest type, ownership, species, stand basal area, tree class, diameter, and height. Information is presented for total tree, stem, and crown components.

The woody biomass resource of Louisiana, 1991

Treesearch

James F. Rosson

1993-01-01

Tabulates fresh and dry biomass estimates of major trees in Louisiana by forest type, ownership, species, stand basal area, tree class, diameter, and height. Information is presented for total tree, stem, and crown components.

Descriptive study of damage caused by the rhinoceros beetle, Oryctes agamemnon, and its influence on date palm oases of Rjim Maatoug, Tunisia.

PubMed

Soltani, Rasmi; Lkbel, Chaieb; Habib Ben Hamouda, Med

2008-01-01

Oryctes agamemnon (Burmeister 1847) (Coleoptera, Scarabaeidae) was accidentally introduced in the southwestern oases of Tunisia (Tozeur) around 1980 and spread to the Rjim Maatoug region. In these areas O. agamemnon was specific to date palm trees causing severe damage that can result in potential danger due to collapse of the tree. This study was conducted from April 2004 to March 2006 in 4 sites in the region of Rjim Maatoug. Different levels of palm tree attack were determined, ovioposition sites were identified, and pest damage was described in detail to specify their relative importance and to indicate factors governing palm tree attack. Eggs were individually oviposited in the attacked parts. Dead parts of palm trees were the main target of O. agamemnon including the respiratory roots, tough, trunk bark, dry petiole and the periphery of the crown. The crown itself was not attacked. Feeding by larvae caused significant damage. The biggest danger occurred when heavy attacks of larvae invaded the respiratory roots at the level of the soil, and secondarily on the periphery of the crown, which can result in fungal diseases. Several cases of Deglet Nour date palm tree collapse were caused by this pest in Rjim Maatoug. Attacks on other parts of the tree were without danger for the palm tree. In the absence of pest management, application of a quarantine program combined with field cultivation techniques could help farmers significantly decrease attack of O. agamemnon on palm trees.

Leaf reflectance variation along a vertical crown gradient of two deciduous tree species in a Belgian industrial habitat.

PubMed

Khavaninzadeh, Ali Reza; Veroustraete, Frank; Van Wittenberghe, Shari; Verrelst, Jochem; Samson, Roeland

2015-09-01

The reflectometry of leaf asymmetry is a novel approach in the bio-monitoring of tree health in urban or industrial habitats. Leaf asymmetry responds to the degree of environmental pollution and reflects structural changes in a leaf due to environmental pollution. This paper describes the boundary conditions to scale up from leaf to canopy level reflectance, by describing the variability of adaxial and abaxial leaf reflectance, hence leaf asymmetry, along the crown height gradients of two tree species. Our findings open a research pathway towards bio-monitoring based on the airborne remote sensing of tree canopies and their leaf asymmetric properties. Copyright © 2015 Elsevier Ltd. All rights reserved.

Coast redwood live crown and sapwood

Treesearch

John-Pascal Berrill; Jesse L. Deffress; Jessica M. Engle

2012-01-01

Understanding crown rise and sapwood taper will help meet management objectives such as producing long branch-free boles for clear wood and old-growth restoration, or producing sawlogs with a high proportion of heartwood. Coast redwood (Sequoia sempervirens) tree crown ratio data were collected 20 years after partial harvesting in a 65-year-old second growth stand....

Models for estimation and simulation of crown and canopy cover

Treesearch

John D. Shaw

2005-01-01

Crown width measurements collected during Forest Inventory and Analysis and Forest Health Monitoring surveys are being used to develop individual tree crown width models and plot-level canopy cover models for species and forest types in the Intermountain West. Several model applications are considered in the development process, including remote sensing of plot...

Olive Actual "on Year" Yield Forecast Tool Based on the Tree Canopy Geometry Using UAS Imagery.

PubMed

Sola-Guirado, Rafael R; Castillo-Ruiz, Francisco J; Jiménez-Jiménez, Francisco; Blanco-Roldan, Gregorio L; Castro-Garcia, Sergio; Gil-Ribes, Jesus A

2017-07-30

Olive has a notable importance in countries of Mediterranean basin and its profitability depends on several factors such as actual yield, production cost or product price. Actual "on year" Yield (AY) is production (kg tree -1 ) in "on years", and this research attempts to relate it with geometrical parameters of the tree canopy. Regression equation to forecast AY based on manual canopy volume was determined based on data acquired from different orchard categories and cultivars during different harvesting seasons in southern Spain. Orthoimages were acquired with unmanned aerial systems (UAS) imagery calculating individual crown for relating to canopy volume and AY. Yield levels did not vary between orchard categories; however, it did between irrigated orchards (7000-17,000 kg ha -1 ) and rainfed ones (4000-7000 kg ha -1 ). After that, manual canopy volume was related with the individual crown area of trees that were calculated by orthoimages acquired with UAS imagery. Finally, AY was forecasted using both manual canopy volume and individual tree crown area as main factors for olive productivity. AY forecast only by using individual crown area made it possible to get a simple and cheap forecast tool for a wide range of olive orchards. Finally, the acquired information was introduced in a thematic map describing spatial AY variability obtained from orthoimage analysis that may be a powerful tool for farmers, insurance systems, market forecasts or to detect agronomical problems.

A benchmark study for the crown-type splashing dynamics of one- and two-component droplet wall-film interactions

NASA Astrophysics Data System (ADS)

Geppert, A.; Terzis, A.; Lamanna, G.; Marengo, M.; Weigand, B.

2017-12-01

The present paper investigates experimentally the impact dynamics of crown-type splashing for miscible two- and one-component droplet wall-film interactions over a range of Weber numbers and dimensionless film thicknesses. The splashing outcome is parametrised in terms of a set of quantifiable parameters, such as crown height, top and base diameter, wall inclination, number of fingers, and secondary droplet properties. The results show that the outcome of a splashing event is not affected by the choice of similar or dissimilar fluids, provided the dimensionless film thickness is larger than 0.1. Below this threshold, distinctive features of two-component interactions appear, such as hole formation and crown bottom breakdown. The observation of different crown shapes (e.g. V-shaped, cylindrical, and truncated-cone) confirms that vorticity production induces changes in the crown wall inclination, thus affecting the evolution of the crown height and top diameter. The evolution of the crown base diameter, instead, is mainly dependent on the relative importance of liquid inertia and viscous losses in the wall-film. The maximum number of liquid fingers decreases with increasing wall, film thickness, due to the enhanced attenuation of the effect of surface properties on the fingering process. The formation of secondary droplets is also affected by changes in the crown wall inclination. In particular, for truncated-cone shapes the occurrence of crown rim contraction induces a large scatter in the secondary droplet properties. Consequently, empirical models for the maximum number and mean diameter of the secondary droplets are derived for V-shaped crowns, as observed for the hexadecane-Hyspin interactions.

Widespread crown condition decline, food web disruption, and amplified tree mortality with increased climate change-type drought

PubMed Central

Carnicer, Jofre; Coll, Marta; Ninyerola, Miquel; Pons, Xavier; Sánchez, Gerardo; Peñuelas, Josep

2011-01-01

Climate change is progressively increasing severe drought events in the Northern Hemisphere, causing regional tree die-off events and contributing to the global reduction of the carbon sink efficiency of forests. There is a critical lack of integrated community-wide assessments of drought-induced responses in forests at the macroecological scale, including defoliation, mortality, and food web responses. Here we report a generalized increase in crown defoliation in southern European forests occurring during 1987–2007. Forest tree species have consistently and significantly altered their crown leaf structures, with increased percentages of defoliation in the drier parts of their distributions in response to increased water deficit. We assessed the demographic responses of trees associated with increased defoliation in southern European forests, specifically in the Iberian Peninsula region. We found that defoliation trends are paralleled by significant increases in tree mortality rates in drier areas that are related to tree density and temperature effects. Furthermore, we show that severe drought impacts are associated with sudden changes in insect and fungal defoliation dynamics, creating long-term disruptive effects of drought on food webs. Our results reveal a complex geographical mosaic of species-specific responses to climate change–driven drought pressures on the Iberian Peninsula, with an overwhelmingly predominant trend toward increased drought damage. PMID:21220333

Widespread crown condition decline, food web disruption, and amplified tree mortality with increased climate change-type drought.

PubMed

Carnicer, Jofre; Coll, Marta; Ninyerola, Miquel; Pons, Xavier; Sánchez, Gerardo; Peñuelas, Josep

2011-01-25

Climate change is progressively increasing severe drought events in the Northern Hemisphere, causing regional tree die-off events and contributing to the global reduction of the carbon sink efficiency of forests. There is a critical lack of integrated community-wide assessments of drought-induced responses in forests at the macroecological scale, including defoliation, mortality, and food web responses. Here we report a generalized increase in crown defoliation in southern European forests occurring during 1987-2007. Forest tree species have consistently and significantly altered their crown leaf structures, with increased percentages of defoliation in the drier parts of their distributions in response to increased water deficit. We assessed the demographic responses of trees associated with increased defoliation in southern European forests, specifically in the Iberian Peninsula region. We found that defoliation trends are paralleled by significant increases in tree mortality rates in drier areas that are related to tree density and temperature effects. Furthermore, we show that severe drought impacts are associated with sudden changes in insect and fungal defoliation dynamics, creating long-term disruptive effects of drought on food webs. Our results reveal a complex geographical mosaic of species-specific responses to climate change-driven drought pressures on the Iberian Peninsula, with an overwhelmingly predominant trend toward increased drought damage.

Relation of initial spacing and relative stand density indices to stand characteristics in a Douglas-fir plantation spacing trial

USGS Publications Warehouse

Curtis, Robert O.; Bansal, Sheel; Harrington, Constance A.

2016-01-01

This report presents updated information on a 1981 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) plantation spacing trial at 33 years from planting. Stand statistics at the most recent measurement were compared for initial spacing of 1 through 6 meters and associated relative densities. There was no clear relationship of spacing to top height. Diameter, live crown ratio, and percent survival increased with spacing; basal area and relative density decreased with increase in spacing. Volume in trees ≥ 4 cm diameter was greatest at 2 m spacing, while utilizable volume (trees ≥20 cm dbh) was greatest at 4 m spacing. Live crown ratio decreased and total crown projectional area increased with increasing relative density indices. Total crown projectional area was more closely related to relative density than to basal area.

Hydrostatic constraints on morphological exploitation of light in tall Sequoia sempervirens trees.

PubMed

Ishii, Hiroaki T; Jennings, Gregory M; Sillett, Stephen C; Koch, George W

2008-07-01

We studied changes in morphological and physiological characteristics of leaves and shoots along a height gradient in Sequoia sempervirens, the tallest tree species on Earth, to investigate whether morphological and physiological acclimation to the vertical light gradient was constrained by hydrostatic limitation in the upper crown. Bulk leaf water potential (Psi) decreased linearly and light availability increased exponentially with increasing height in the crown. During the wet season, Psi was lower in the outer than inner crown. C isotope composition of leaves (delta(13)C) increased with increasing height indicating greater photosynthetic water use efficiency in the upper crown. Leaf and shoot morphology changed continuously with height. In contrast, their relationships with light availability were discontinuous: morphological characteristics did not correspond to increasing light availability above 55-85 m. Mass-based chlorophyll concentration (chl) decreased with increasing height and increasing light availability. In contrast, area-based chl remained constant or increased with increasing height. Mass-based maximum rate of net photosynthesis (P (max)) decreased with increasing height, whereas area-based P (max) reached maximum at 78.4 m and decreased with increasing height thereafter. Mass-based P (max) increased with increasing shoot mass per area (SMA), whereas area-based P (max) was not correlated with SMA in the upper crown. Our results suggest that hydrostatic limitation of morphological development constrains exploitation of light in the upper crown and contributes to reduced photosynthetic rates and, ultimately, reduced height growth at the tops of tall S. sempervirens trees.

Explaining biomass growth of tropical canopy trees: the importance of sapwood.

PubMed

van der Sande, Masha T; Zuidema, Pieter A; Sterck, Frank

2015-04-01

Tropical forests are important in worldwide carbon (C) storage and sequestration. C sequestration of these forests may especially be determined by the growth of canopy trees. However, the factors driving variation in growth among such large individuals remain largely unclear. We evaluate how crown traits [total leaf area, specific leaf area and leaf nitrogen (N) concentration] and stem traits [sapwood area (SA) and sapwood N concentration] measured for individual trees affect absolute biomass growth for 43 tropical canopy trees belonging to four species, in a moist forest in Bolivia. Biomass growth varied strongly among trees, between 17.3 and 367.3 kg year(-1), with an average of 105.4 kg year(-1). We found that variation in biomass growth was chiefly explained by a positive effect of SA, and not by tree size or other traits examined. SA itself was positively associated with sapwood growth, sapwood lifespan and basal area. We speculate that SA positively affects the growth of individual trees mainly by increasing water storage, thus securing water supply to the crown. These positive roles of sapwood on growth apparently offset the increased respiration costs incurred by more sapwood. This is one of the first individual-based studies to show that variation in sapwood traits-and not crown traits-explains variation in growth among tropical canopy trees. Accurate predictions of C dynamics in tropical forests require similar studies on biomass growth of individual trees as well as studies evaluating the dual effect of sapwood (water provision vs. respiratory costs) on tropical tree growth.

A GIS-based approach to stand visualization and spatial pattern analysis in a mixed hardwood forest in West Virginia

Treesearch

Benktesh D. Sharma; Jingxin Wang; Gary Miller

2008-01-01

Tree spatial patterns were characterized for a 75-year-old mixed hardwood forest dominated by northern red oak, chestnut oak, red maple and yellow-poplar. All trees ≥5 inches diameter at breast height (d.b.h.) were measured for diameter, total height, crown height, and crown width along with their locations in the field over an area of 8 acres. The spatial...

Ground-based remote sensing with long lens video camera for upper-stem diameter and other tree crown measurements

Treesearch

Neil A. Clark; Sang-Mook Lee

2004-01-01

This paper demonstrates how a digital video camera with a long lens can be used with pulse laser ranging in order to collect very large-scale tree crown measurements. The long focal length of the camera lens provides the magnification required for precise viewing of distant points with the trade-off of spatial coverage. Multiple video frames are mosaicked into a single...

Three-year bole response of white oak (Quercus alba L.) crop trees to fertilizer and crown release on a Tennessee upland site

Treesearch

G. Richard Schaertl; Allan E. Houston; Edward R. Buckner; James S. Meadows

1997-01-01

Bole diameter responses to fertilization, crown release, and fertilization x release treatments with untreated controls and treatment-by-year interactions were studied in pole-sized (approx. 43 years old) white oak (Quercus alba L.) crop trees. In the main study, fertilizer was applied by broadcast to plots at a rate of 150 lbs N and 35 lbs P

Tree detection in orchards from VHR satellite images using scale-space theory

NASA Astrophysics Data System (ADS)

Mahour, Milad; Tolpekin, Valentyn; Stein, Alfred

2016-10-01

This study focused on extracting reliable and detailed information from very High Resolution (VHR) satellite images for the detection of individual trees in orchards. The images contain detailed information on spectral and geometrical properties of trees. Their scale level, however, is insufficient for spectral properties of individual trees, because adjacent tree canopies interlock. We modeled trees using a bell shaped spectral profile. Identifying the brightest peak was challenging due to sun illumination effects caused 1 by differences in positions of the sun and the satellite sensor. Crown boundary detection was solved by using the NDVI from the same image. We used Gaussian scale-space methods that search for extrema in the scale-space domain. The procedures were tested on two orchards with different tree types, tree sizes and tree observation patterns in Iran. Validation was done using reference data derived from an UltraCam digital aerial photo. Local extrema of the determinant of the Hessian corresponded well to the geographical coordinates and the size of individual trees. False detections arising from a slight asymmetry of trees were distinguished from multiple detections of the same tree with different extents. Uncertainty assessment was carried out on the presence and spatial extents of individual trees. The study demonstrated how the suggested approach can be used for image segmentation for orchards with different types of trees. We concluded that Gaussian scale-space theory can be applied to extract information from VHR satellite images for individual tree detection. This may lead to improved decision making for irrigation and crop water requirement purposes in future studies.

Object-based methods for individual tree identification and tree species classification from high-spatial resolution imagery

NASA Astrophysics Data System (ADS)

Wang, Le

2003-10-01

Modern forest management poses an increasing need for detailed knowledge of forest information at different spatial scales. At the forest level, the information for tree species assemblage is desired whereas at or below the stand level, individual tree related information is preferred. Remote Sensing provides an effective tool to extract the above information at multiple spatial scales in the continuous time domain. To date, the increasing volume and readily availability of high-spatial-resolution data have lead to a much wider application of remotely sensed products. Nevertheless, to make effective use of the improving spatial resolution, conventional pixel-based classification methods are far from satisfactory. Correspondingly, developing object-based methods becomes a central challenge for researchers in the field of Remote Sensing. This thesis focuses on the development of methods for accurate individual tree identification and tree species classification. We develop a method in which individual tree crown boundaries and treetop locations are derived under a unified framework. We apply a two-stage approach with edge detection followed by marker-controlled watershed segmentation. Treetops are modeled from radiometry and geometry aspects. Specifically, treetops are assumed to be represented by local radiation maxima and to be located near the center of the tree-crown. As a result, a marker image was created from the derived treetop to guide a watershed segmentation to further differentiate overlapping trees and to produce a segmented image comprised of individual tree crowns. The image segmentation method developed achieves a promising result for a 256 x 256 CASI image. Then further effort is made to extend our methods to the multiscales which are constructed from a wavelet decomposition. A scale consistency and geometric consistency are designed to examine the gradients along the scale-space for the purpose of separating true crown boundary from unwanted textures occurring due to branches and twigs. As a result from the inverse wavelet transform, the tree crown boundary is enhanced while the unwanted textures are suppressed. Based on the enhanced image, an improvement is achieved when applying the two-stage methods to a high resolution aerial photograph. To improve tree species classification, we develop a new method to choose the optimal scale parameter with the aid of Bhattacharya Distance (BD), a well-known index of class separability in traditional pixel-based classification. The optimal scale parameter is then fed in the process of a region-growing-based segmentation as a break-off value. Our object classification achieves a better accuracy in separating tree species when compared to the conventional Maximum Likelihood Classification (MLC). In summary, we develop two object-based methods for identifying individual trees and classifying tree species from high-spatial resolution imagery. Both methods achieve promising results and will promote integration of Remote Sensing and GIS in forest applications.

Releasing yellow birch saplings and poles

Treesearch

Gayne G. Erdmann; Ralph M., Jr. Peterson

1992-01-01

Yellow birch needs moisture, nutrients, overhead light, and enough space for the crown to expand in order to compete successfully with faster-growing northern hardwoods. By releasing crowns early, you can increase the number of future veneer and saw log trees in a stand and double the growth rate, thus cutting rotations in half. If you delay crown release too long,...

Estimating forest canopy bulk density using six indirect methods

Treesearch

Robert E. Keane; Elizabeth D. Reinhardt; Joe Scott; Kathy Gray; James Reardon

2005-01-01

Canopy bulk density (CBD) is an important crown characteristic needed to predict crown fire spread, yet it is difficult to measure in the field. Presented here is a comprehensive research effort to evaluate six indirect sampling techniques for estimating CBD. As reference data, detailed crown fuel biomass measurements were taken on each tree within fixed-area plots...

Landsat TM Classifications For SAFIS Using FIA Field Plots

Treesearch

William H. Cooke; Andrew J. Hartsell

2001-01-01

Wall-to-wall Landsat Thematic Mapper (TM) classification efforts in Georgia require field validation. We developed a new crown modeling procedure based on Forest Health Monitoring (FHM) data to test Forest Inventory and Analysis (FIA) data. These models simulate the proportion of tree crowns that reflect light on a FIA subplot basis. We averaged subplot crown...

A system for automatically recording weight changes in sapling trees

Treesearch

Harold F. Haupt; Bud L. Jeffers

1967-01-01

Describes an accurate and simple system for taking continuous weight records of sapling-size trees. Measurements obtained using this system have helped in describing the mechanism of interception storage in tree crowns during snowfall.

How to estimate weights of northern red oak crowns in a stand.

Treesearch

Robert M. Loomis; Richard W. Blank

1982-01-01

Describes how to estimate the weights of northern red oak and other hardwood tree crowns that could become fuels after storms, logging, or insect epidemics. Presents tables, sample worksheets, and examples.

Mistletoe effects on Scots pine decline following drought events: insights from within-tree spatial patterns, growth and carbohydrates.

PubMed

Sangüesa-Barreda, Gabriel; Linares, Juan Carlos; Camarero, J Julio

2012-05-01

Forest decline has been attributed to the interaction of several stressors including biotic factors such as mistletoes and climate-induced drought stress. However, few data exist on how mistletoes are spatially arranged within trees and how this spatial pattern is related to changes in radial growth, responses to drought stress and carbon use. We used dendrochronology to quantify how mistletoe (Viscum album L.) infestation and drought stress affected long-term growth patterns in Pinus sylvestris L. at different heights. Basal area increment (BAI) trends and comparisons between trees of three different infestation degrees (without mistletoe, ID1; moderately infested trees, ID2; and severely infested trees, ID3) were performed using linear mixed-effects models. To identify the main climatic drivers of tree growth tree-ring widths were converted into indexed chronologies and related to climate data using correlation functions. We performed spatial analyses of the 3D distribution of mistletoe individuals and their ages within the crowns of three severely infested pines to describe their patterns. Lastly, we quantified carbohydrate and nitrogen concentrations in needles and sapwood of branches from severely infested trees and from trees without mistletoe. Mistletoe individuals formed strongly clustered groups of similar age within tree crowns and their age increased towards the crown apex. Mistletoe infestation negatively impacted growth but this effect was stronger near the tree apex than in the rest of sampled heights, causing an average loss of 64% in BAI (loss of BAI was ∼51% at 1.3 m or near the tree base). We found that BAI of severely infested trees and moderately or non-infested trees diverged since 2001 and such divergence was magnified by drought. Infested trees had lower concentrations of soluble sugars in their needles than non-infested ones. We conclude that mistletoe infestation causes growth decline and increases the sensitivity of trees to drought stress.

Cambial activity related to tree size in a mature silver-fir plantation.

PubMed

Rathgeber, Cyrille B K; Rossi, Sergio; Bontemps, Jean-Daniel

2011-09-01

Our knowledge about the influences of environmental factors on tree growth is principally based on the study of dominant trees. However, tree social status may influence intra-annual dynamics of growth, leading to differential responses to environmental conditions. The aim was to determine whether within-stand differences in stem diameters of trees belonging to different crown classes resulted from variations in the length of the growing period or in the rate of cell production. Cambial activity was monitored weekly in 2006 for three crown classes in a 40-year-old silver-fir (Abies alba) plantation near Nancy (France). Timings, duration and rate of tracheid production were assessed from anatomical observations of the developing xylem. Cambial activity started earlier, stopped later and lasted longer in dominant trees than in intermediate and suppressed ones. The onset of cambial activity was estimated to have taken 3 weeks to spread to 90 % of the trees in the stand, while the cessation needed 6 weeks. Cambial activity was more intense in dominant trees than in intermediate and suppressed ones. It was estimated that about 75 % of tree-ring width variability was attributable to the rate of cell production and only 25 % to its duration. Moreover, growth duration was correlated to tree height, while growth rate was better correlated to crown area. These results show that, in a closed conifer forest, stem diameter variations resulted principally from differences in the rate of xylem cell production rather than in its duration. Tree size interacts with environmental factors to control the timings, duration and rate of cambial activity through functional processes involving source-sink relationships principally, but also hormonal controls.

Intra- and interspecific variation in tropical tree and liana phenology derived from Unmanned Aerial Vehicle images

NASA Astrophysics Data System (ADS)

Bohlman, S.; Park, J.; Muller-Landau, H. C.; Rifai, S. W.; Dandois, J. P.

2017-12-01

Phenology is a critical driver of ecosystem processes. There is strong evidence that phenology is shifting in temperate ecosystems in response to climate change, but tropical tree and liana phenology remains poorly quantified and understood. A key challenge is that tropical forests contain hundreds of plant species with a wide variety of phenological patterns. Satellite-based observations, an important source of phenology data in northern latitudes, are hindered by frequent cloud cover in the tropics. To quantify phenology over a large number of individuals and species, we collected bi-weekly images from unmanned aerial vehicles (UAVs) in the well-studied 50-ha forest inventory plot on Barro Colorado Island, Panama. Between October 2014 and December 2015 and again in May 2015, we collected a total of 35 sets of UAV images, each with continuous coverage of the 50-ha plot, where every tree ≥ 1 cm DBH is mapped. Spectral, texture, and image information was extracted from the UAV images for individual tree crowns, which was then used as inputs for a machine learning algorithm to predict percent leaf and branch cover. We obtained the species identities of 2000 crowns in the images via field mapping. The objectives of this study are to (1) determined if machine learning algorithms, applied to UAV images, can effectively quantify changes in leaf cover, which we term "deciduousness; (2) determine how liana cover effects deciduousness and (3) test how well UAV-derived deciduousness patterns match satellite-derived temporal patterns. Machine learning algorithms trained on a variety of image parameters could effectively determine leaf cover, despite variation in lighting and viewing angles. Crowns with higher liana cover have less overall deciduousness (tree + liana together) than crowns with lower liana cover. Individual crown deciduousness, summed over all crowns measured in the 50-ha plot, showed a similar seasonal pattern as MODIS EVI composited over 10 years. However, MODIS EVI phenology was "greened" up earlier than UAV-based deciduousness, perhaps reflecting the new late dry season leaf flush that increases EVI but not overall leaf cover. We discuss how the potential mechanisms that explain variation among species and between trees and lianas and the consequences for these variation for ecosystem processes and modeling.

A dual growing method for the automatic extraction of individual trees from mobile laser scanning data

NASA Astrophysics Data System (ADS)

Li, Lin; Li, Dalin; Zhu, Haihong; Li, You

2016-10-01

Street trees interlaced with other objects in cluttered point clouds of urban scenes inhibit the automatic extraction of individual trees. This paper proposes a method for the automatic extraction of individual trees from mobile laser scanning data, according to the general constitution of trees. Two components of each individual tree - a trunk and a crown can be extracted by the dual growing method. This method consists of coarse classification, through which most of artifacts are removed; the automatic selection of appropriate seeds for individual trees, by which the common manual initial setting is avoided; a dual growing process that separates one tree from others by circumscribing a trunk in an adaptive growing radius and segmenting a crown in constrained growing regions; and a refining process that draws a singular trunk from the interlaced other objects. The method is verified by two datasets with over 98% completeness and over 96% correctness. The low mean absolute percentage errors in capturing the morphological parameters of individual trees indicate that this method can output individual trees with high precision.

High-Throughput 3-D Monitoring of Agricultural-Tree Plantations with Unmanned Aerial Vehicle (UAV) Technology

PubMed Central

Torres-Sánchez, Jorge; López-Granados, Francisca; Serrano, Nicolás; Arquero, Octavio; Peña, José M.

2015-01-01

The geometric features of agricultural trees such as canopy area, tree height and crown volume provide useful information about plantation status and crop production. However, these variables are mostly estimated after a time-consuming and hard field work and applying equations that treat the trees as geometric solids, which produce inconsistent results. As an alternative, this work presents an innovative procedure for computing the 3-dimensional geometric features of individual trees and tree-rows by applying two consecutive phases: 1) generation of Digital Surface Models with Unmanned Aerial Vehicle (UAV) technology and 2) use of object-based image analysis techniques. Our UAV-based procedure produced successful results both in single-tree and in tree-row plantations, reporting up to 97% accuracy on area quantification and minimal deviations compared to in-field estimations of tree heights and crown volumes. The maps generated could be used to understand the linkages between tree grown and field-related factors or to optimize crop management operations in the context of precision agriculture with relevant agro-environmental implications. PMID:26107174

High-Throughput 3-D Monitoring of Agricultural-Tree Plantations with Unmanned Aerial Vehicle (UAV) Technology.

PubMed

Torres-Sánchez, Jorge; López-Granados, Francisca; Serrano, Nicolás; Arquero, Octavio; Peña, José M

2015-01-01

The geometric features of agricultural trees such as canopy area, tree height and crown volume provide useful information about plantation status and crop production. However, these variables are mostly estimated after a time-consuming and hard field work and applying equations that treat the trees as geometric solids, which produce inconsistent results. As an alternative, this work presents an innovative procedure for computing the 3-dimensional geometric features of individual trees and tree-rows by applying two consecutive phases: 1) generation of Digital Surface Models with Unmanned Aerial Vehicle (UAV) technology and 2) use of object-based image analysis techniques. Our UAV-based procedure produced successful results both in single-tree and in tree-row plantations, reporting up to 97% accuracy on area quantification and minimal deviations compared to in-field estimations of tree heights and crown volumes. The maps generated could be used to understand the linkages between tree grown and field-related factors or to optimize crop management operations in the context of precision agriculture with relevant agro-environmental implications.

Descriptive Study of Damage Caused by the Rhinoceros Beetle, Oryctes agamemnon, and Its Influence on Date Palm Oases of Rjim Maatoug, Tunisia

PubMed Central

Soltani, Rasmi; lkbel, Chaieb; Habib Ben Hamouda, Med

2008-01-01

Oryctes agamemnon (Burmeister 1847) (Coleoptera, Scarabaeidae) was accidentally introduced in the southwestern oases of Tunisia (Tozeur) around 1980 and spread to the Rjim Maatoug region. In these areas O. agamemnon was specific to date palm trees causing severe damage that can result in potential danger due to collapse of the tree. This study was conducted from April 2004 to March 2006 in 4 sites in the region of Rjim Maatoug. Different levels of palm tree attack were determined, ovioposition sites were identified, and pest damage was described in detail to specify their relative importance and to indicate factors governing palm tree attack. Eggs were individually oviposited in the attacked parts. Dead parts of palm trees were the main target of O. agamemnon including the respiratory roots, tough, trunk bark, dry petiole and the periphery of the crown. The crown itself was not attacked. Feeding by larvae caused significant damage. The biggest danger occurred when heavy attacks of larvae invaded the respiratory roots at the level of the soil, and secondarily on the periphery of the crown, which can result in fungal diseases. Several cases of Deglet Nour date palm tree collapse were caused by this pest in Rjim Maatoug. Attacks on other parts of the tree were without danger for the palm tree. In the absence of pest management, application of a quarantine program combined with field cultivation techniques could help farmers significantly decrease attack of O. agamemnon on palm trees. PMID:20302545

The woody biomass resource of East Oklahoma, 1993

Treesearch

James F. Rosson

1993-01-01

Tables are presented for fresh and dry biomass estimates of major trees in east Oklahoma by forest type, ownership, species, stand basal area, tree class, diameter, and height. Information for total tree, stem, and crown components is included.

User's Manual for Total-Tree Multiproduct Cruise Program

Treesearch

Alexander Clark; Thomas M. Burgan; Richard C. Field; Peter E. Dress

1985-01-01

This interactive computer program uses standard tree-cruise data to estimate the weight and volume of the total tree, saw logs, plylogs, chipping logs, pulpwood, crown firewood, and logging residue in timber stands.Input is cumulative cruise data for tree counts by d.b.h. and height. Output is in tables: board-foot volume by d.b.h.; total-tree and tree-component...

The structure of tropical forests and sphere packings

PubMed Central

Jahn, Markus Wilhelm; Dobner, Hans-Jürgen; Wiegand, Thorsten; Huth, Andreas

2015-01-01

The search for simple principles underlying the complex architecture of ecological communities such as forests still challenges ecological theorists. We use tree diameter distributions—fundamental for deriving other forest attributes—to describe the structure of tropical forests. Here we argue that tree diameter distributions of natural tropical forests can be explained by stochastic packing of tree crowns representing a forest crown packing system: a method usually used in physics or chemistry. We demonstrate that tree diameter distributions emerge accurately from a surprisingly simple set of principles that include site-specific tree allometries, random placement of trees, competition for space, and mortality. The simple static model also successfully predicted the canopy structure, revealing that most trees in our two studied forests grow up to 30–50 m in height and that the highest packing density of about 60% is reached between the 25- and 40-m height layer. Our approach is an important step toward identifying a minimal set of processes responsible for generating the spatial structure of tropical forests. PMID:26598678

Predicting behavior and size of crown fires in the northern Rocky Mountains

Treesearch

Richard C. Rothermel

1991-01-01

Describes methods for approximating behavior and size of a wind-driven crown fire in mountainous terrain. Covers estimation of average rate of spread, energy release from tree crowns and surface fuel, fireline intensity, flame length, and unit area power of the fire and ambient wind. Plume-dominated fires, which may produce unexpectedly fast spread rates even with low...

Predicting mortality of ponderosa pine regeneration after prescribed fire in the Black Hills, South Dakota, USA

Treesearch

Mike Battaglia; Frederick W. Smith; Wayne D. Shepperd

2009-01-01

Reduction of crown fire hazard in Pinus ponderosa forests in the Black Hills, SD, often focuses on the removal of overstorey trees to reduce crown bulk density. Dense ponderosa pine regeneration establishes several years after treatment and eventually increases crown fire risk if allowed to grow. Using prescribed fire to control this regeneration is...

Crown characteristics of juvenile loblolly pine 6 years after application of thinning and fertilization

Treesearch

Shufang Yu; Jim L. Chambers; Zhenmin Tang; James P. Barnett

2003-01-01

Total foliage dry mass and leaf area at the canopy hierarchical level of needle, shoot, branch and crown were measured in 48 trees harvested from a 14-year-old loblolly pine (Pinus taeda L.) plantation, six growing seasons after thinning and fertilization treatments. In the unthinned treatment, upper crown needles were heavier and had more leaf area...

Surface fire effects on conifer and hardwood crowns--applications of an integral plume model

Treesearch

Matthew Dickinson; Anthony Bova; Kathleen Kavanagh; Antoine Randolph; Lawrence Band

2009-01-01

An integral plume model was applied to the problems of tree death from canopy injury in dormant-season hardwoods and branch embolism in Douglas fir (Pseudotsuga menziesii) crowns. Our purpose was to generate testable hypotheses. We used the integral plume models to relate crown injury to bole injury and to explore the effects of variation in fire...

The Relationship of Bole Diameters and Crown Widths of Seven Bottomland Hardwood Species

Treesearch

John K. Francis

1988-01-01

Diameters, heights, and eight crown radii per tree were measured on 75 individuals from each of seven bottomland hardwood species in Mississippi. It was determined that the seven species could not be described by a single regression equation. Crown class was tested to see whether it significantly influenced the slope or intercept of the linear relationship. Three of...

Tree species classification using within crown localization of waveform LiDAR attributes

NASA Astrophysics Data System (ADS)

Blomley, Rosmarie; Hovi, Aarne; Weinmann, Martin; Hinz, Stefan; Korpela, Ilkka; Jutzi, Boris

2017-11-01

Since forest planning is increasingly taking an ecological, diversity-oriented perspective into account, remote sensing technologies are becoming ever more important in assessing existing resources with reduced manual effort. While the light detection and ranging (LiDAR) technology provides a good basis for predictions of tree height and biomass, tree species identification based on this type of data is particularly challenging in structurally heterogeneous forests. In this paper, we analyse existing approaches with respect to the geometrical scale of feature extraction (whole tree, within crown partitions or within laser footprint) and conclude that currently features are always extracted separately from the different scales. Since multi-scale approaches however have proven successful in other applications, we aim to utilize the within-tree-crown distribution of within-footprint signal characteristics as additional features. To do so, a spin image algorithm, originally devised for the extraction of 3D surface features in object recognition, is adapted. This algorithm relies on spinning an image plane around a defined axis, e.g. the tree stem, collecting the number of LiDAR returns or mean values of returns attributes per pixel as respective values. Based on this representation, spin image features are extracted that comprise only those components of highest variability among a given set of library trees. The relative performance and the combined improvement of these spin image features with respect to non-spatial statistical metrics of the waveform (WF) attributes are evaluated for the tree species classification of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and Silver/Downy birch (Betula pendula Roth/Betula pubescens Ehrh.) in a boreal forest environment. This evaluation is performed for two WF LiDAR datasets that differ in footprint size, pulse density at ground, laser wavelength and pulse width. Furthermore, we evaluate the robustness of the proposed method with respect to internal parameters and tree size. The results reveal, that the consideration of the crown-internal distribution of within-footprint signal characteristics captured in spin image features improves the classification results in nearly all test cases.

Automated identification and geometrical features extraction of individual trees from Mobile Laser Scanning data in Budapest

NASA Astrophysics Data System (ADS)

Koma, Zsófia; Székely, Balázs; Folly-Ritvay, Zoltán; Skobrák, Ferenc; Koenig, Kristina; Höfle, Bernhard

2016-04-01

Mobile Laser Scanning (MLS) is an evolving operational measurement technique for urban environment providing large amounts of high resolution information about trees, street features, pole-like objects on the street sides or near to motorways. In this study we investigate a robust segmentation method to extract the individual trees automatically in order to build an object-based tree database system. We focused on the large urban parks in Budapest (Margitsziget and Városliget; KARESZ project) which contained large diversity of different kind of tree species. The MLS data contained high density point cloud data with 1-8 cm mean absolute accuracy 80-100 meter distance from streets. The robust segmentation method contained following steps: The ground points are determined first. As a second step cylinders are fitted in vertical slice 1-1.5 meter relative height above ground, which is used to determine the potential location of each single trees trunk and cylinder-like object. Finally, residual values are calculated as deviation of each point from a vertically expanded fitted cylinder; these residual values are used to separate cylinder-like object from individual trees. After successful parameterization, the model parameters and the corresponding residual values of the fitted object are extracted and imported into the tree database. Additionally, geometric features are calculated for each segmented individual tree like crown base, crown width, crown length, diameter of trunk, volume of the individual trees. In case of incompletely scanned trees, the extraction of geometric features is based on fitted circles. The result of the study is a tree database containing detailed information about urban trees, which can be a valuable dataset for ecologist, city planners, planting and mapping purposes. Furthermore, the established database will be the initial point for classification trees into single species. MLS data used in this project had been measured in the framework of KARESZ project for whole Budapest. BSz contributed as an Alexander von Humboldt Research Fellow.

No strong evidence for increasing liana abundance in the Myristicaceae of a Neotropical aseasonal rain forest.

PubMed

Smith, James R; Queenborough, Simon A; Alvia, Pablo; Romero-Saltos, Hugo; Valencia, Renato

2017-02-01

The "liana dominance hypothesis" posits that lianas are increasing in abundance in tropical forests, thereby potentially reducing tree biomass due to competitive interactions between trees and lianas. This scenario has implications not only for forest ecosystem function and species composition, but also climate change given the mass of carbon stored in tropical trees. In 2003 and 2013, all Myristicaceae trees in the 50-ha Yasuní Forest Dynamics Plot, Ecuador, were surveyed for liana presence and load in their crowns. We tested the hypothesis that the proportion of trees with lianas increased between 2003 and 2013 in line with the liana dominance hypothesis. Contrary to expectations, the total proportion of trees with lianas decreased from 35% to 32%, and when only trees ≥10 cm diameter at breast height were considered liana incidence increased 44-48%. Liana load was dynamic with a large proportion of trees losing or gaining lianas over the 10-yr period; large trees with intermediate liana loads increased in proportion at the expense of those with low and high loads. Lianas also impacted performance: trees with 26-75% crown cover by lianas in 2003 had reduced growth rates of 80% compared to of liana-free trees, and trees with >75% crown cover had 33% the growth rate and a log odds of mortality eight times that of liana-free trees. We suggest that the lack of strong support found for the liana dominance hypothesis is likely due to the aseasonal climate of Yasuní, which limits the competitive advantage lianas maintain over trees during dry seasons due to their efficient capture and use of water. We propose further research of long-term liana dynamics from aseasonal forests is required to determine the generality of the increasing liana dominance hypothesis in Neotropical forests. © 2016 by the Ecological Society of America.

Effects of declining oak vitality on ecosystem functions: Lessons from a Spanish oak woodland

NASA Astrophysics Data System (ADS)

López-Sánchez, Aida; Bareth, Georg; Bolten, Andreas; Linstädter, Anja

2017-04-01

Mediterranean oak woodlands have a great ecological and socio-economic importance. Today, these fragile ecosystems are facing unprecedented degradation threats from Novel Oak Diseases (NODs). Among NOD drivers, maladapted land management practices and climate change are most important. Although it is generally believed that NOD-related declines in tree vitality will have detrimental effects on ecosystem functions, little is known on the magnitude of change, and whether different functions are affected in a similar way. Here we analyzed effects of tree vitality on various ecosystem functions, comparing subcanopy and intercanopy habitats across two oak species (Quercus ilex and Q. suber) in a Spanish oak woodland. We asked how functions - including aboveground net primary productivity (ANPP), taxonomic diversity, and litter decomposition rates - were affected by oak trees' size and vitality. We also combined measurements in the ecosystem function habitat index (MEFHI), a proxy of ecosystem multifunctionality. Field research was carried out in 2016 on a dehesa in southern Spain. We used a stratified random sampling to contrast trees of different species affiliation, size and vitality. Tree vitality was estimated as crown density (assessed via hemispherical photography), and as tree vigor, which combines the grade of canopy defoliation with proxies for tree size (dbh, height, crown height and crown radius). For each tree (n = 34), two plots (50 x 50 cm) were located; one in the subcanopy habitat, and the other in the intercanopy area beyond the tree crown's influence. On all 68 plots, moveable cages were placed during the main growth period (March to May) to estimate ANPP under grazed conditions. Litter decomposition rates were assessed via the tea bag index. ANPP and the biomass of grasses, forbs and legumes were recorded via destructive sampling. To take plots' highly variable environmental conditions into account, we recorded a suite of abiotic and biotic characteristics such as the received radiation of the hydrological year, slope, aspect, soil depth, grazing offtake, as well as the cover of bare ground and litter. The geo-morphological data comes from a high resolution UAV generated digital elevation model. We used GLMMs and LMMs to assess effects of tree health on ecosystem functions, statistically controlling for plots' variable environmental conditions. We found ANPP to be higher in intercanopy habitats and beneath trees with a low vigor or crown density. In contrast, highly vigorous trees increased legume biomass and grass biomass. Responses of other ecosystem functions were mostly not significant, although a lower diversity was found under trees with intermediate vigor. In the case of MEFHI, we assume that positive and negative responses have partly masked each other. Our results underline that a NOD-related decline in tree vitality has complex effects on ecosystem functions. For example, it increases forage quantity but decreases forage quality. Ecosystem functions under trees with a low vigor were in most cases similar to those in adjacent open habitats, showing that the presence of vigorous (i.e. old and vital) trees is critical for maintaining ecosystem functions on a landscape level. Keywords: NODs, dehesa, ANNP, decomposition, herb diversity, habitat degradation

Additivity in tree biomass components of Pyrenean oak (Quercus pyrenaica Willd.)

Treesearch

Joao P. Carvalho; Bernard R. Parresol

2003-01-01

In tree biomass estimations, it is important to consider the property of additivity, i.e., the total tree biomass should equal the sum of the components. This work presents functions that allow estimation of the stem and crown dry weight components of Pyrenean oak (Quercus pyrenaica Willd.) trees. A procedure that considers additivity of tree biomass...

Automated methods of tree boundary extraction and foliage transparency estimation from digital imagery

Treesearch

Sang-Mook Lee; Neil A. Clark; Philip A. Araman

2003-01-01

Foliage transparency in trees is an important indicator for forest health assessment. This paper helps advance transparency measurement research by presenting methods of automatic tree boundary extraction and foliage transparency estimation from digital images taken from the ground of open grown trees.Extraction of proper boundaries of tree crowns is the...

Testing microdensitometric ability to determine Monterey pine urban tree stress

Treesearch

David J. Nowak; Joe R. McBride

1993-01-01

Microdensitometric analysis of aerial photographs has been used to quantify urban tree stress of deciduous species. A test of this procedure applied to Monterey pine indicates that variations in ground cover beneath urban trees among cities and variations in crown morphology among tree species can limit the ability of microdensitometry to quantify urban tree stress....

Estimation of pedestrian level UV exposure under trees

Treesearch

Richard H. Grant; Gordon M. Heisler; Wei Gao

2002-01-01

Trees influence the amount of solar UV radiation that reaches pedestrians. A three-dimensional model was developed to predict the ultraviolet-B (UV-B) irradiance fields in open-tree canopies where the spacing between trees is equal to or greater than the width of individual tree crowns. The model predicted the relative irradiance (fraction of above-canopy irradiance)...

Urban forest ecosystem analysis using fused airborne hyperspectral and lidar data

NASA Astrophysics Data System (ADS)

Alonzo, Mike Gerard

Urban trees are strategically important in a city's effort to mitigate their carbon footprint, heat island effects, air pollution, and stormwater runoff. Currently, the most common method for quantifying urban forest structure and ecosystem function is through field plot sampling. However, taking intensive structural measurements on private properties throughout a city is difficult, and the outputs from sample inventories are not spatially explicit. The overarching goal of this dissertation is to develop methods for mapping urban forest structure and function using fused hyperspectral imagery and waveform lidar data at the individual tree crown scale. Urban forest ecosystem services estimated using the USDA Forest Service's i-Tree Eco (formerly UFORE) model are based largely on tree species and leaf area index (LAI). Accordingly, tree species were mapped in my Santa Barbara, California study area for 29 species comprising >80% of canopy. Crown-scale discriminant analysis methods were introduced for fusing Airborne Visible Infrared Imaging Spectrometry (AVIRIS) data with a suite of lidar structural metrics (e.g., tree height, crown porosity) to maximize classification accuracy in a complex environment. AVIRIS imagery was critical to achieving an overall species-level accuracy of 83.4% while lidar data was most useful for improving the discrimination of small and morphologically unique species. LAI was estimated at both the field-plot scale using laser penetration metrics and at the crown scale using allometry. Agreement of the former with photographic estimates of gap fraction and the latter with allometric estimates based on field measurements was examined. Results indicate that lidar may be used reasonably to measure LAI in an urban environment lacking in continuous canopy and characterized by high species diversity. Finally, urban ecosystem services such as carbon storage and building energy-use modification were analyzed through combination of aforementioned methods and the i-Tree Eco modeling framework. The remote sensing methods developed in this dissertation will allow researchers to more precisely constrain urban ecosystem spatial analyses and equip cities to better manage their urban forest resource.

Contaminant exposure of birds nesting in Green Bay, Wisconsin, USA

USGS Publications Warehouse

Custer, Thomas W.; Dummer, Paul M.; Custer, Christine M.; Franson, J. Christian; Jones, Michael

2014-01-01

In earlier studies, elevated concentrations of polychlorinated biphenyl (PCB) and p,p'-dichlorodiphenyldichloroethylene (DDE) were reported in double-crested cormorant (Phalacrocorax auritus) eggs and tree swallow (Tachycineta bicolor) eggs and nestlings collected from lower Green Bay (WI, USA) in 1994 and 1995 and black-crowned night-heron (Nycticorax nycticorax) eggs collected in 1991. Comparable samples collected in 2010 and 2011 indicated that concentrations of PCBs were 35%, 62%, 70%, and 88% lower than in the early 1990s in tree swallow eggs, tree swallow nestlings, double-crested cormorant eggs, and black-crowned night-heron eggs, respectively; concentrations of DDE were 47%, 43%, 51%, and 80% lower, respectively. These declines are consistent with regional contaminant trends in other species. Concentrations of PCBs were higher in herring gull (Larus argentatus) than in black-crowned night-heron eggs collected from Green Bay in 2010; PCB concentrations in double-crested cormorant and tree swallow eggs were intermediate. The estimated toxicity of the PCB mixture in eggs of the insectivorous tree swallow was the equal to or greater than toxicity in the 3 piscivorous bird species. A multivariate analysis indicated that the composition percentage of lower-numbered PCB congeners was greater in eggs of the insectivorous tree swallow than in eggs of the 3 piscivorous species nesting in Green Bay. Dioxin and furan concentrations and the toxicity of these chemicals were also higher in tree swallows than these other waterbird species nesting in Green Bay.

Contaminant exposure of birds nesting in Green Bay, Wisconsin, USA.

PubMed

Custer, Thomas W; Dummer, Paul M; Custer, Christine M; Franson, J Christian; Jones, Michael

2014-08-01

In earlier studies, elevated concentrations of polychlorinated biphenyl (PCB) and p,p'-dichlorodiphenyldichloroethylene (DDE) were reported in double-crested cormorant (Phalacrocorax auritus) eggs and tree swallow (Tachycineta bicolor) eggs and nestlings collected from lower Green Bay (WI, USA) in 1994 and 1995 and black-crowned night-heron (Nycticorax nycticorax) eggs collected in 1991. Comparable samples collected in 2010 and 2011 indicated that concentrations of PCBs were 35%, 62%, 70%, and 88% lower than in the early 1990s in tree swallow eggs, tree swallow nestlings, double-crested cormorant eggs, and black-crowned night-heron eggs, respectively; concentrations of DDE were 47%, 43%, 51%, and 80% lower, respectively. These declines are consistent with regional contaminant trends in other species. Concentrations of PCBs were higher in herring gull (Larus argentatus) than in black-crowned night-heron eggs collected from Green Bay in 2010; PCB concentrations in double-crested cormorant and tree swallow eggs were intermediate. The estimated toxicity of the PCB mixture in eggs of the insectivorous tree swallow was the equal to or greater than toxicity in the 3 piscivorous bird species. A multivariate analysis indicated that the composition percentage of lower-numbered PCB congeners was greater in eggs of the insectivorous tree swallow than in eggs of the 3 piscivorous species nesting in Green Bay. Dioxin and furan concentrations and the toxicity of these chemicals were also higher in tree swallows than these other waterbird species nesting in Green Bay. Published 2014 Wiley Periodicals, Inc.

A method for reconstructing the development of the sapwood area of balsam fir.

PubMed

Coyea, M R; Margolis, H A; Gagnon, R R

1990-09-01

Leaf area is commonly estimated as a function of sapwood area. However, because sapwood changes to heartwood over time, it has not previously been possible to reconstruct either the sapwood area or the leaf area of older trees into the past. In this study, we report a method for reconstructing the development of the sapwood area of dominant and codominant balsam fir (Abies balsamea (L.) Mill.). The technique is based on establishing a species-specific relationship between the number of annual growth rings in the sapwood area and tree age. Because the number of annual growth rings in the sapwood of balsam fir at a given age was found to be independent of site quality and stand density, the number of rings in sapwood (NRS) can be predicted from the age of a tree thus: NRS = 14.818 (1 - e(-0.031 age)), unweighted R(2) = 0.80, and NRS = 2.490 (1 - e(-0.038 age)), unweighted R(2) = 0.64, for measurements at breast height and at the base of the live crown, respectively. These nonlinear asymptotic regression models based only on age, were not improved by adding other tree variables such as diameter at breast height, diameter at the base of the live crown, total tree height or percent live crown.

Biotic mortality factors affecting emerald ash borer (Agrilus planipennis) are highly dependent on life stage and host tree crown condition.

PubMed

Jennings, D E; Duan, J J; Shrewsbury, P M

2015-10-01

Emerald ash borer (EAB), Agrilus planipennis, is a serious invasive forest pest in North America responsible for killing tens to hundreds of millions of ash trees since it was accidentally introduced in the 1990 s. Although host-plant resistance and natural enemies are known to be important sources of mortality for EAB in Asia, less is known about the importance of different sources of mortality at recently colonized sites in the invaded range of EAB, and how these relate to host tree crown condition. To further our understanding of EAB population dynamics, we used a large-scale field experiment and life-table analyses to quantify the fates of EAB larvae and the relative importance of different biotic mortality factors at 12 recently colonized sites in Maryland. We found that the fates of larvae were highly dependent on EAB life stage and host tree crown condition. In relatively healthy trees (i.e., with a low EAB infestation) and for early instars, host tree resistance was the most important mortality factor. Conversely, in more unhealthy trees (i.e., with a moderate to high EAB infestation) and for later instars, parasitism and predation were the major sources of mortality. Life-table analyses also indicated how the lack of sufficient levels of host tree resistance and natural enemies contribute to rapid population growth of EAB at recently colonized sites. Our findings provide further evidence of the mechanisms by which EAB has been able to successfully establish and spread in North America.

Spectral analysis of white ash response to emerald ash borer infestations

NASA Astrophysics Data System (ADS)

Calandra, Laura

The emerald ash borer (EAB) (Agrilus planipennis Fairmaire) is an invasive insect that has killed over 50 million ash trees in the US. The goal of this research was to establish a method to identify ash trees infested with EAB using remote sensing techniques at the leaf-level and tree crown level. First, a field-based study at the leaf-level used the range of spectral bands from the WorldView-2 sensor to determine if there was a significant difference between EAB-infested white ash (Fraxinus americana) and healthy leaves. Binary logistic regression models were developed using individual and combinations of wavelengths; the most successful model included 545 and 950 nm bands. The second half of this research employed imagery to identify healthy and EAB-infested trees, comparing pixel- and object-based methods by applying an unsupervised classification approach and a tree crown delineation algorithm, respectively. The pixel-based models attained the highest overall accuracies.

Recovery efficiency of whole-tree harvesting

Treesearch

Bryce J. Stokes; William F. Watson

1988-01-01

The recovery of total tree biomass and most components of a stand is a practical economic and management alternative to tree-length harvesting. First, the increased utilization of woody biomass provides additional revenues from the site. Second, the removal and utilization of the stems and crowns reduces site preparation costs and makes tree planting easier. Third,...

A generalized system of models forecasting Central States tree growth.

Treesearch

Stephen R. Shifley

1987-01-01

Describes the development and testing of a system of individual tree-based growth projection models applicable to species in Indiana, Missouri, and Ohio. Annual tree basal area growth is estimated as a function of tree size, crown ratio, stand density, and site index. Models are compatible with the STEMS and TWIGS Projection System.

Wall-to-wall Landsat TM classifications for Georgia in support of SAFIS using FIA plots for training and verification

Treesearch

William H. Cooke; Andrew J. Hartsell

2000-01-01

Wall-to-wall Landsat TM classification efforts in Georgia require field validation. Validation uslng FIA data was testing by developing a new crown modeling procedure. A methodology is under development at the Southern Research Station to model crown diameter using Forest Health monitoring data. These models are used to simulate the proportion of tree crowns that...

The structure of western warbler assemblages: Analysis of foraging behavior and habitat selection in Oregon

USGS Publications Warehouse

Morrison, Michael L.

1981-01-01

This study examines the foraging behavior and habitat selection of a MacGillivray's (Oporornis tolmiei)-Orange-crowned (Vermivora celata)-Wilson's (Wilsonia pusilla) warbler assemblage that occurred on early-growth clearcuts in western Oregon during breeding. Sites were divided into two groups based on the presence or absence of deciduous trees. Density estimates for each species were nearly identical between site classes except for Wilson's, whose density declined on nondeciduous tree sites. Analysis of vegetation parameters within the territories of the species identified deciduous tree cover as the variable of primary importance in the separation of warblers on each site, so that the assemblage could be arranged on a continuum of increasing deciduous tree cover. MacGillivray's and Wilson's extensively used shrub cover and deciduous tree cover, respectively; Orange-crowns were associated with both vegetation types. When the deciduous tree cover was reduced, Orange-crowns concentrated foraging activities in shrub cover and maintained nondisturbance densities. Indices of foraging-height diversity showed a marked decrease after the removal of deciduous trees. All species except MacGillivray's foraged lower in the vegatative substrate on the nondeciduous tree sites; MacGillivray's concentrated foraging activities in the low shrub cover on both sites. Indices of foraging overlap revealed a general pattern of decreased segregation by habitat after removal of deciduous trees. I suggest that the basic patterns of foraging behavior and habitat selection evidenced today in western North America were initially developed by ancestral warblers before their invasion of the west. Species successfully colonizing western habitats were probably preadapted to the conditions they encountered, with new habitats occupied without obvious evolutionary modifications.

Large-Scale Mixed Temperate Forest Mapping at the Single Tree Level using Airborne Laser Scanning

NASA Astrophysics Data System (ADS)

Scholl, V.; Morsdorf, F.; Ginzler, C.; Schaepman, M. E.

2017-12-01

Monitoring vegetation on a single tree level is critical to understand and model a variety of processes, functions, and changes in forest systems. Remote sensing technologies are increasingly utilized to complement and upscale the field-based measurements of forest inventories. Airborne laser scanning (ALS) systems provide valuable information in the vertical dimension for effective vegetation structure mapping. Although many algorithms exist to extract single tree segments from forest scans, they are often tuned to perform well in homogeneous coniferous or deciduous areas and are not successful in mixed forests. Other methods are too computationally expensive to apply operationally. The aim of this study was to develop a single tree detection workflow using leaf-off ALS data for the canton of Aargau in Switzerland. Aargau covers an area of over 1,400km2 and features mixed forests with various development stages and topography. Forest type was classified using random forests to guide local parameter selection. Canopy height model-based treetop maxima were detected and maintained based on the relationship between tree height and window size, used as a proxy to crown diameter. Watershed segmentation was used to generate crown polygons surrounding each maximum. The location, height, and crown dimensions of single trees were derived from the ALS returns within each polygon. Validation was performed through comparison with field measurements and extrapolated estimates from long-term monitoring plots of the Swiss National Forest Inventory within the framework of the Swiss Federal Institute for Forest, Snow, and Landscape Research. This method shows promise for robust, large-scale single tree detection in mixed forests. The single tree data will aid ecological studies as well as forest management practices. Figure description: Height-normalized ALS point cloud data (top) and resulting single tree segments (bottom) on the Laegeren mountain in Switzerland.

Changes in Mauna Kea Dry Forest Structure 2000-2014

USGS Publications Warehouse

Banko, Paul C.; Brinck, Kevin W.

2014-01-01

Changes in the structure of the subalpine vegetation of Palila Critical Habitat on the southwestern slope of Mauna Kea Volcano, Hawai‘i, were analyzed using 12 metrics of change in māmane (Sophora chrysophylla) and naio (Myoporum sandwicense) trees surveyed on plots in 2000 and 2014. These two dominant species were analyzed separately, and changes in their structure indicated changes in the forest’s health. There was a significant increase in māmane minimum crown height (indicating a higher ungulate “browse line”), canopy area, canopy volume, percentage of trees with ungulate damage, and percentage of dead trees. No significant changes were observed in māmane maximum crown height, proportion of plots with trees, sapling density, proportion of plots with saplings, or the height distribution of trees. The only significant positive change was for māmane tree density. Significantly negative changes were observed for naio minimum crown height, tree height, canopy area, canopy volume, and percentage of dead trees. No significant changes were observed in naio tree density, proportion of plots with trees, proportion of plots with saplings, or percentage of trees with ungulate damage. Significantly positive changes were observed in naio sapling density and the height distribution of trees. There was also a significant increase in the proportion of māmane vs. naio trees in the survey area. The survey methods did not allow us to distinguish among potential factors driving these changes for metrics other than the percentage of trees with ungulate damage. Continued ungulate browsing and prolonged drought are likely the factors contributing most to the observed changes in vegetation, but tree disease or insect infestation of māmane, or naio, and competition from alien grasses and other weeds could also be causing or exacerbating the impacts to the forest. Although māmane tree density has increased since 2000, this study also demonstrates that efforts by managers to remove sheep (Ovis spp.) from Palila Critical Habitat have not overcome the ability of sheep to continue to damage māmane trees and impede restoration of the vegetation.

Olive Actual “on Year” Yield Forecast Tool Based on the Tree Canopy Geometry Using UAS Imagery

PubMed Central

Sola-Guirado, Rafael R.; Castillo-Ruiz, Francisco J.; Jiménez-Jiménez, Francisco; Blanco-Roldan, Gregorio L.; Gil-Ribes, Jesus A.

2017-01-01

Olive has a notable importance in countries of Mediterranean basin and its profitability depends on several factors such as actual yield, production cost or product price. Actual “on year” Yield (AY) is production (kg tree−1) in “on years”, and this research attempts to relate it with geometrical parameters of the tree canopy. Regression equation to forecast AY based on manual canopy volume was determined based on data acquired from different orchard categories and cultivars during different harvesting seasons in southern Spain. Orthoimages were acquired with unmanned aerial systems (UAS) imagery calculating individual crown for relating to canopy volume and AY. Yield levels did not vary between orchard categories; however, it did between irrigated orchards (7000–17,000 kg ha−1) and rainfed ones (4000–7000 kg ha−1). After that, manual canopy volume was related with the individual crown area of trees that were calculated by orthoimages acquired with UAS imagery. Finally, AY was forecasted using both manual canopy volume and individual tree crown area as main factors for olive productivity. AY forecast only by using individual crown area made it possible to get a simple and cheap forecast tool for a wide range of olive orchards. Finally, the acquired information was introduced in a thematic map describing spatial AY variability obtained from orthoimage analysis that may be a powerful tool for farmers, insurance systems, market forecasts or to detect agronomical problems. PMID:28758945

Taxonomic differences in deciduous upper second molar crown outlines of Homo sapiens, Homo neanderthalensis and Homo erectus.

PubMed

Bailey, Shara E; Benazzi, Stefano; Souday, Caroline; Astorino, Claudia; Paul, Kathleen; Hublin, Jean-Jacques

2014-07-01

A significant number of Middle to Late Pleistocene sites contain primarily (and sometimes only) deciduous teeth (e.g., Grotta del Cavallo, Mezmaiskaya, Blombos). Not surprisingly, there has been a recent renewed interest in deciduous dental variation, especially in the context of distinguishing Homo neanderthalensis and Homo sapiens. Most studies of the deciduous dentition of fossil hominins have focused on standard metrical variation but morphological (non-metric and morphometric) variation also promises to shed light on long standing taxonomic questions. This study examines the taxonomic significance of the crown outline of the deciduous upper second molar through principal components analysis and linear discriminant analysis. We examine whether or not the crown shape of the upper deciduous second molar separates H. neanderthalensis from H. sapiens and explore whether it can be used to correctly assign individuals to taxa. It builds on previous studies by focusing on crown rather than cervical outline and by including a large sample of geographically diverse recent human populations. Our samples include 17 H. neanderthalensis, five early H. sapiens, and 12 Upper Paleolithic H. sapiens. In addition, we include two Homo erectus specimens in order to evaluate the polarity of crown shape differences observed between H. neanderthalensis and H. sapiens. Our results show that crown outline shape discriminates H. sapiens and H. neanderthalensis quite well, but does not do well at distinguishing H. erectus from H. sapiens. We conclude that the crown outline shape observed in H. sapiens is a primitive retention and that the skewed shape observed in H. neanderthalensis is a derived condition. Finally, we explore the phylogenetic implications of the results for the H. erectus molars. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of herbicide release on the growth of 8- to 12-year-old hardwood trees

Treesearch

G.W. Wendel; Neil I. Lamson; Neil I. Lamson

1987-01-01

In 8- to 12-year-old Appalachian hardwood stands, crop trees were released by stem injecting competing trees with a 20 percent aqueous solution of glyphosate. Species released were black cherry, red oak, and sugar maple. Release treatments were (a) injection of all trees within a 5-foot radius of the crop tree bole and (b) injections of all trees whose crown touched...

Models relating stem growth to crown length dynamics: application to loblolly pine and Norway spruce

Treesearch

Harry T. Valentine; Annikki Makela; Edward J. Green; Ralph L. Amateis; Harri Makinen; Mark J. Ducey

2012-01-01

We derive and analyze a model that relates the growth rate of cross-sectional area ('csa') at any height on the central stem of a tree to crown-length dynamics. The derivation is based, in part, on assumptions that (a) active csa on the central stem relates allometrically to the length of crown above the cross section, and (b) inactive csa is proportional to...

Evaluating elevated levels of crown dieback among northern white-cedar (Thuja occidentalis L.) trees in Maine and Michigan: a summary of evaluation monitoring

Treesearch

KaDonna Randolph; William A. Bechtold; Randall S. Morin; Stanley J. Zarnoch

2012-01-01

Analysis of crown condition data for the 2006 national technical report of the Forest Health Monitoring (FHM) Program of the Forest Service, U.S. Department of Agriculture, exposed clusters of phase 3 plots (by the Forest Inventory and Analysis [FIA] Program of the Forest Service) with northern white-cedar (Thuja occidentalis L.) crown dieback...

Critical mass flux for flaming ignition of wood as a function of external radiant heat flux and moisture content

Treesearch

S. McAllister; M. Finney; J. Cohen

2011-01-01

Extreme weather often contributes to crown fires, where the fire spreads from one tree crown to the next as a series of piloted ignitions. An important aspect in predicting crown fires is understanding the ignition of fuel particles. The ignition criterion considered in this work is the critical mass flux criterion - that a sufficient amount of pyrolysis gases must be...

Critical mass flux for flaming ignition of dead, dry wood as a function of exernal radiant heat flux

Treesearch

Sara McAllister; Mark Finney; Jack Cohen

2010-01-01

Extreme weather often contributes to crown fires, where the fire spreads from one tree crown to the next as a series of piloted ignitions. An important aspect in predicting crown fires is understanding the ignition of fuel particles. The ignition criterion considered in this work is the critical mass flux criterion - that a sufficient amount of pyrolysis gases must be...

The Relationship of Diameter at Breast Height and Crown Diameter for Four Species Groups in Hardin County, Tennessee

Treesearch

Lawrence R. Gering; Dennis M. May

1995-01-01

A set of simple linear regression models for predicting diameter at breast height (dbh) from crown diamter and a set of similar models for predicting crown diamter from dbh were developed for four species groups in Harding County, TN. Data were obtained from 557 trees measured during hte 1989 USDA Southern Forest Experiment Station survey of the forest of Tennessee,...

Tree growth prediction using size and exposed crown area

Treesearch

Peter H. Wyckoff; James S. Clark

2005-01-01

We address the relationships between tree growth rate and growing environment for 21 co-occurring species. Tree growth rates are obtained from mapped plots at the Coweeta Long-Term Ecological Research site in the southern Appalachian Mountains. We employ high-resolution aerial photography to assess the light environment for trees growing in these plots, using exposed...

Some correlations between sugar maple tree characteristics and sap and sugar yields

Treesearch

Barton M. Blum

1971-01-01

Simple correlation coefficients between various characteristics of sugar maple trees and sap sugar concentration, sap volume yield, and total sugar production are given for the 1968 sap season. Correlation coefficients in general indicated that individual tree characteristics that express tree and crown size are significantly related to sap volume yield and total sugar...

Tree-centered spot firing - a technique for prescribed burning beneath standing trees.

Treesearch

C. Phillip Weatherspoon; George A. Almond; Carl N. Skinner

1989-01-01

Prescribed burning beneath standing trees normally requires efforts to protect residual trees from excessive fire damage. Damage to both crowns and boles is strongly influenced by flame length, a fire characteristic functionally related to fireline intensity (Albini 1976). In a good prescribed burn, therefore, the prescription specifies desired or maximum flame lengths...

Releasing 75- to 80-year-old Appalachian hardwood sawtimber trees--5-year d.b.h. response

Treesearch

H.C. Smith; G.W. Miller

1991-01-01

Generally, mature trees on good growing sites are seldom thinned or released. Instead, at maturity the trees are harvested. Data were summarized from north-central West Virginia study areas (northern red oak site index 70 feet and above) where mature trees were released on all sides of the crown (full release).

Asian Longhorned Beetle - A New Introduction, Pest Alert

Treesearch

USDA Forest Service, State and Private Forestry, Northeastern Area; Animal and Plant Health Inspection Service

2008-01-01

The Asian longhorned beetle (ALB) has been discovered attacking trees in the United States. Tunneling by beetle larvae girdles tree stems and branches. Repeated attacks lead to dieback of the tree crown and, eventually, death of the tree. ALB probably traveled to the United States inside solid wood packing material from China. The beetle has been intercepted at ports...

Midday Depression vs. Midday Peak in Diurnal Light Interception: Contrasting Patterns at Crown and Leaf Scales in a Tropical Evergreen Tree.

PubMed

Ventre-Lespiaucq, Agustina; Flanagan, Nicola S; Ospina-Calderón, Nhora H; Delgado, Juan A; Escudero, Adrián

2018-01-01

Crown architecture usually is heterogeneous as a result of foraging in spatially and temporally heterogeneous light environments. Ecologists are only beginning to identify the importance of temporal heterogeneity for light acquisition in plants, especially at the diurnal scale. Crown architectural heterogeneity often leads to a diurnal variation in light interception. However, maximizing light interception during midday may not be an optimal strategy in environments with excess light. Instead, long-lived plants are expected to show crown architectures and leaf positions that meet the contrasting needs of light interception and avoidance of excess light on a diurnal basis. We expected a midday depression in the diurnal course of light interception both at the whole-crown and leaf scales, as a strategy to avoid the interception of excessive irradiance. We tested this hypothesis in a population of guava trees ( Psidium guajava L.) growing in an open tropical grassland. We quantified three crown architectural traits: intra-individual heterogeneity in foliage clumping, crown openness, and leaf position angles. We estimated the diurnal course of light interception at the crown scale using hemispheric photographs, and at the leaf scale using the cosine of solar incidence. Crowns showed a midday depression in light interception, while leaves showed a midday peak. These contrasting patterns were related to architectural traits. At the crown scale, the midday depression of light interception was linked to a greater crown openness and foliage clumping in crown tops than in the lateral parts of the crown. At the leaf scale, an average inclination angle of 45° led to the midday peak in light interception, but with a huge among-leaf variation in position angles. The mismatch in diurnal course of light interception at crown and leaf scales can indicate that different processes are being optimized at each scale. These findings suggest that the diurnal course of light interception may be an important dimension of the resource acquisition strategies of long-lived woody plants. Using a temporal approach as the one applied here may improve our understanding of the diversity of crown architectures found across and within environments.

Midday Depression vs. Midday Peak in Diurnal Light Interception: Contrasting Patterns at Crown and Leaf Scales in a Tropical Evergreen Tree

PubMed Central

Ventre-Lespiaucq, Agustina; Flanagan, Nicola S.; Ospina-Calderón, Nhora H.; Delgado, Juan A.; Escudero, Adrián

2018-01-01

Crown architecture usually is heterogeneous as a result of foraging in spatially and temporally heterogeneous light environments. Ecologists are only beginning to identify the importance of temporal heterogeneity for light acquisition in plants, especially at the diurnal scale. Crown architectural heterogeneity often leads to a diurnal variation in light interception. However, maximizing light interception during midday may not be an optimal strategy in environments with excess light. Instead, long-lived plants are expected to show crown architectures and leaf positions that meet the contrasting needs of light interception and avoidance of excess light on a diurnal basis. We expected a midday depression in the diurnal course of light interception both at the whole-crown and leaf scales, as a strategy to avoid the interception of excessive irradiance. We tested this hypothesis in a population of guava trees (Psidium guajava L.) growing in an open tropical grassland. We quantified three crown architectural traits: intra-individual heterogeneity in foliage clumping, crown openness, and leaf position angles. We estimated the diurnal course of light interception at the crown scale using hemispheric photographs, and at the leaf scale using the cosine of solar incidence. Crowns showed a midday depression in light interception, while leaves showed a midday peak. These contrasting patterns were related to architectural traits. At the crown scale, the midday depression of light interception was linked to a greater crown openness and foliage clumping in crown tops than in the lateral parts of the crown. At the leaf scale, an average inclination angle of 45° led to the midday peak in light interception, but with a huge among-leaf variation in position angles. The mismatch in diurnal course of light interception at crown and leaf scales can indicate that different processes are being optimized at each scale. These findings suggest that the diurnal course of light interception may be an important dimension of the resource acquisition strategies of long-lived woody plants. Using a temporal approach as the one applied here may improve our understanding of the diversity of crown architectures found across and within environments. PMID:29904391

On the relationship between gingival biotypes and supracrestal gingival height, crown form and papilla height.

PubMed

Fischer, Kai R; Grill, Eva; Jockel-Schneider, Yvonne; Bechtold, Markus; Schlagenhauf, Ulrich; Fickl, Stefan

2014-08-01

To determine the association between gingival biotypes and supracrestal gingival height (primary aim) and its relation to crown shape and papilla height (secondary aim). Eighty adult subjects were evaluated in this study. Based on the transparency of a periodontal probe through the buccal gingival margin, 38 subjects comprised the thin biotype group and 42 subjects comprised the thick biotype group, respectively. Three different parameters were clinically assessed: supracrestal gingival height (SGH) by bone sounding, crown width/crown length ratio and papilla height. No statistical difference (P > 0.05) was detected neither for the correlation between different biotypes (thick/thin) and SGH nor for the association of biotypes and crown width/crown length ratio. Papilla height was only significantly increased (P ≤ 0.05) in the area of teeth no. 21/22 for the thin periodontal biotype. Intra-examiner deviation was found to be very low for all clinical parameters (percentile agreement > 95%). Within the limits of this study, we found that in young Caucasians (i) soft tissue dimensions seem to be similar between biotypes (ii) and the traditional hypothesis that a thick gingiva merges with broad-short crown shape and flat papillae and a thin gingiva with a narrow-long crown shape and high scalloping, may be questionable. © 2013 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Identification and Mapping of Tree Species in Urban Areas Using WORLDVIEW-2 Imagery

NASA Astrophysics Data System (ADS)

Mustafa, Y. T.; Habeeb, H. N.; Stein, A.; Sulaiman, F. Y.

2015-10-01

Monitoring and mapping of urban trees are essential to provide urban forestry authorities with timely and consistent information. Modern techniques increasingly facilitate these tasks, but require the development of semi-automatic tree detection and classification methods. In this article, we propose an approach to delineate and map the crown of 15 tree species in the city of Duhok, Kurdistan Region of Iraq using WorldView-2 (WV-2) imagery. A tree crown object is identified first and is subsequently delineated as an image object (IO) using vegetation indices and texture measurements. Next, three classification methods: Maximum Likelihood, Neural Network, and Support Vector Machine were used to classify IOs using selected IO features. The best results are obtained with Support Vector Machine classification that gives the best map of urban tree species in Duhok. The overall accuracy was between 60.93% to 88.92% and κ-coefficient was between 0.57 to 0.75. We conclude that fifteen tree species were identified and mapped at a satisfactory accuracy in urban areas of this study.

Response to crop-tree release by 7-year-old stems of yellow-poplar and black cherry

Treesearch

G.R. Jr. Trimble; G.R. Jr. Trimble

1973-01-01

Five years after crop-tree release of yellow-poplar and black cherry sterns in a 7-year-old stand of Appalachian hardwoods, measurements indicated that released trees were but slightly superior to control trees in height, diameter, and crown position. Sprout regrowth of cut tree stems and grapevines had largely nullified the effects of release. Indications are that for...

Ontogenetic changes in size, allometry, and mechanical design of tropical rain forest trees.

PubMed

Sterck, F; Bongers, F

1998-02-01

Size, allometry, and mechanical design were measured for trees of three canopy species in a tropical rain forest in French Guiana. Mechanical design was expressed as the safety factor, using the elastic-stability model, and the wind resistance factor, using the constant-stress model. Changes with ontogeny were described as regressions using stem diameter as the independent variable, and they were compared between species. Height, crown size, and the wind resistance factor increased with ontogeny. The safety factor decreased to a minimum and then increased continuously in thicker trees. The crown width/height ratio did not change with ontogeny. Interspecific differences in allometry and mechanical design were related to the adult stature of the species, and not to shade tolerance. The short stature species (Vouacapoua americana) was less slender (height:DBH [stem diameter at 1.3 m] ratio) and had a higher crown width/height ratio than the tall stature species (Goupia glabra and Dicorynia guianensis). Vouacapoua had a higher safety factor, but a similar wind resistance factor. The safety factors of our study species were lower than those of two temperate tree species because of a higher slenderness. Differences in safety factors between tropical and temperate trees may result from unrealistic assumptions of the elastic-stability model, and may also be related to lower light levels and-or wind rates in the tropics.

Arboreal nests of Phenacomys longgicaudus in Oregon.

Treesearch

A.M. Gillesberg; A.B. Carey

1991-01-01

Searching felled trees proved effective for finding nests of Phenacomys longicaudus; 117 nests were found in 50 trees. Nests were located throughout the live crowns, but were concentrated in the lower two-thirds of the canopy. Abundance of nests increased with tree size; old-growth forests provide optimum habitat.

Above-ground weights for tamarack in northeastern Minnesota.

Treesearch

Eugene M. Carpenter

1983-01-01

We used trees from natural uneven-aged stands in northeastern Minnesota to develop prediction equations to estimate total tree, stem, crown, live and dead branch weight. Presented here are specific gravity and moisture content by d.b.h. and height in tree, as well as bark, sapwood, and heartwood ratios.

Comparison of Stem Map Developed from Crown Geometry Allometry Linked Census Data to Airborne and Terrestrial Lidar at Harvard Forest, MA

NASA Astrophysics Data System (ADS)

Sullivan, F.; Palace, M. W.; Ducey, M. J.; David, O.; Cook, B. D.; Lepine, L. C.

2014-12-01

Harvard Forest in Petersham, MA, USA is the location of one of the temperate forest plots established by the Center for Tropical Forest Science (CTFS) as a joint effort with Harvard Forest and the Smithsonian Institute's Forest Global Earth Observatory (ForestGEO) to characterize ecosystem processes and forest dynamics. Census of a 35 ha plot on Prospect Hill was completed during the winter of 2014 by researchers at Harvard Forest. Census data were collected according to CTFS protocol; measured variables included species, stem diameter, and relative X-Y locations. Airborne lidar data were collected over the censused plot using the high spatial resolution Goddard LiDAR, Hyperspectral, and Thermal sensor package (G-LiHT) during June 2012. As part of a separate study, 39 variable radius plots (VRPs) were randomly located and sampled within and throughout the Prospect Hill CTFS/ForestGEO plot during September and October 2013. On VRPs, biometric properties of trees were sampled, including species, stem diameter, total height, crown base height, crown radii, and relative location to plot centers using a 20 Basal Area Factor prism. In addition, a terrestrial-based lidar scanner was used to collect one lidar scan at plot center for 38 of the 39 VRPs. Leveraging allometric equations of crown geometry and tree height developed from 374 trees and 16 different species sampled on 39 VRPs, a 3-dimensional stem map will be created using the Harvard Forest ForestGEO Prospect Hill census. Vertical and horizontal structure of 3d field-based stem maps will be compared to terrestrial and airborne lidar scan data. Furthermore, to assess the quality of allometric equations, a 2d canopy height raster of the field-based stem map will be compared to a G-LiHT derived canopy height model for the 35 ha census plot. Our automated crown delineation methods will be applied to the 2d representation of the census stem map and the G-LiHT canopy height model. For future work related to this study, high quality field-based stem maps with species and crown geometry information will allow for better comparisons and interpretations of individual tree spectra from the G-LiHT hyperspectral sensor as estimated by automated crown delineation of the G-LiHT lidar canopy height model.

Influence of Crown Biomass Estimators and Distribution on Canopy Fuel Characteristics in Ponderosa Pine Stands of the Black Hills

Treesearch

Tara Keyser; Frederick Smith

2009-01-01

Two determinants of crown fire hazard are canopy bulk density (CBD) and canopy base height (CBH). The Fire and Fuels Extension to the Forest Vegetation Simulator (FFE-FVS) is a model that predicts CBD and CBH. Currently, FFE-FVS accounts for neither geographic variation in tree allometries nor the nonuniform distribution of crown mass when one is estimating CBH and CBD...

Crown structure and growth efficiency of red spruce in uneven-aged, mixed-species stands in Maine

Treesearch

Douglas A. Maguire; John C. Brissette; Lianhong. Gu

1998-01-01

Several hypotheses about the relationships among individual tree growth, tree leaf area, and relative tree size or position were tested with red spruce (Picea rubens Sarg.) growing in uneven-aged, mixed-species forests of south-central Maine, U.S.A. Based on data from 65 sample trees, predictive models were developed to (i)...

Distribution of the cone insect, Dioryctria disclusa, in red pine.

Treesearch

William J. Mattson

1976-01-01

Within the crowns of red pine, Pinus resinosa Ait., trees, larvae of the cone insect, Dioryctria disclusa Heinrich, tended to follow the distributions of their foods. Between-tree distributions of larvae, however, were relatable to food distributions in only two of five years. Cone damage/tree by D. disclusa increased linearly with cone abundance per tree when insect...

The influence of conifer forest canopy cover on the accuracy of two individual tree measurement algorithms using lidar data

Treesearch

Michael J. Falkowski; Alistair M.S. Smith; Paul E. Gessler; Andrew T. Hudak; Lee A. Vierling; Jeffrey S. Evans

2008-01-01

Individual tree detection algorithms can provide accurate measurements of individual tree locations, crown diameters (from aerial photography and light detection and ranging (lidar) data), and tree heights (from lidar data). However, to be useful for forest management goals relating to timber harvest, carbon accounting, and ecological processes, there is a need to...

The spatial influence of Pseudotsuga menziesii retention trees on ectomycorrhiza diversity.

Treesearch

D.L. Luoma; C.A. Stockdale; R. Molina; J.L. Eberhart

2006-01-01

This study examines the effect of retained green trees on diversity of mycorrhizal fungi after stand harvest. A significant reduction of mycorrhizal root type richness resulted from the harvest treatment. Samples taken under tree crowns showed no significant decline in the mean number of mycorrhiza types per soil core. In areas well removed from retention trees, there...

Urban tree crown health assessment system: a tool for communities and citizen foresters

Treesearch

Matthew F. Winn; Sang-Mook Lee; Philip A. Araman

2007-01-01

Trees are important assets to urban communities. In addition to the aesthetic values that urban trees provide, they also aid in such things as erosion control, pollution removal, and rainfall interception. The urban environment, however, can often produce stresses to these trees. Soil compaction, limited root growth, and groundwater contamination are just a few of the...

Liberation: Acceptable production of tropical forest timber.

Treesearch

Frank H. Wadsworth; Johan Zweede

2006-01-01

Reduced impact logging in an eastern Amazonian terra firme forest left more than half of the next crop trees growing at a rate corresponding to a rotation of more than a century to attain 60-cm dbh. Two years after the logging, in 20 ha of the logged forest, tree competitors around crop trees were eliminated. Competitors were defined as trees whose crowns overtopped...

Development of Longleaf Pine Seedlings Under Parent Trees

Treesearch

William D. Boyer

1963-01-01

In southwest Alabama, unburned seedlings under overstories ranging up to 90 square feet of basal area per acre survived as well as those with no tree competition. After 7 years, milacre stocking averaged 99 percent and survival 72 percent. Growth, but not survival, improved with distance from parent trees. Seedlings under tree crowns had less brown spot than those in...

Numerical simulation study on the optimization design of the crown shape of PDC drill bit.

PubMed

Ju, Pei; Wang, Zhenquan; Zhai, Yinghu; Su, Dongyu; Zhang, Yunchi; Cao, Zhaohui

The design of bit crown is an important part of polycrystalline diamond compact (PDC) bit design, although predecessors have done a lot of researches on the design principles of PDC bit crown, the study of the law about rock-breaking energy consumption according to different bit crown shape is not very systematic, and the mathematical model of design is over-simplified. In order to analyze the relation between rock-breaking energy consumption and bit crown shape quantificationally, the paper puts forward an idea to take "per revolution-specific rock-breaking work" as objective function, and analyzes the relationship between rock properties, inner cone angle, outer cone arc radius, and per revolution-specific rock-breaking work by means of explicit dynamic finite element method. Results show that the change law between per revolution-specific rock-breaking work and the radius of gyration is similar for rocks with different properties, it is beneficial to decrease rock-breaking energy consumption by decreasing inner cone angle or outer cone arc radius. Of course, we should also consider hydraulic structure and processing technology in the optimization design of PDC bit crown.

Properties of wood from ice-storm damaged loblolly pine trees

Treesearch

David W. Patterson; Jonathan Hartly

2007-01-01

Fifty-sex trees were harvested to determine the properties of the wood produced by ice-storm damaged trees. There were 12 trees each for three classes of bend: () to 15. 16 to 30. and more than 30 degrees from the vertical. Also. 10 trees were selected for each of two classes of crown loss: 20 percent or less and more than 20 percent loss. Samples were taken from three...

Estimating northern red oak crown component weights in the Northeastern United States.

Treesearch

Robert M. Loomis; Richard W. Blank

1981-01-01

Equations are described for estimating crown weights for northern red oak trees. These estimates are for foliage and branchwood weights. Branchwood (wood plus bark) amounts are subdivided by living and dead material into four size groups. Applicability of the equations for other species is examined.

In Situ Quantification of Experimental Ice Accretion on Tree Crowns Using Terrestrial Laser Scanning

PubMed Central

Nock, Charles A.; Greene, David; Delagrange, Sylvain; Follett, Matt; Fournier, Richard; Messier, Christian

2013-01-01

In the eastern hardwood forests of North America ice storms are an important disturbance event. Ice storms strongly influence community dynamics as well as urban infrastructure via catastrophic branch failure; further, the severity and frequency of ice storms are likely to increase with climate change. However, despite a long-standing interest into the effects of freezing rain on forests, the process of ice accretion and thus ice loading on branches remains poorly understood. This is because a number of challenges have prevented in situ measurements of ice on branches, including: 1) accessing and measuring branches in tall canopies, 2) limitations to travel during and immediately after events, and 3) the unpredictability of ice storms. Here, utilizing a novel combination of outdoor experimental icing, manual measurements and terrestrial laser scanning (TLS), we perform the first in situ measurements of ice accretion on branches at differing heights in a tree crown and with increasing duration of exposure. We found that TLS can reproduce both branch and iced branch diameters with high fidelity, but some TLS instruments do not detect ice. Contrary to the expectations of ice accretion models, radial accretion varied sharply within tree crowns. Initially, radial ice accretion was similar throughout the crown, but after 6.5 hours of irrigation (second scanning) radial ice accretion was much greater on upper branches than on lower (∼factor of 3). The slope of the change in radial ice accretion along branches increased with duration of exposure and was significantly greater at the second scanning compared to the first. We conclude that outdoor icing experiments coupled with the use of TLS provide a robust basis for evaluation of models of ice accretion and breakage in tree crowns, facilitating estimation of the limiting breaking stress of branches by accurate measurements of ice loads. PMID:23741409

Using slides to test for changes in crown defoliation assessment methods. Part I: Visual assessment of slides.

PubMed

Dobbertin, Matthias; Hug, Christian; Mizoue, Nobuya

2004-11-01

In this study we used photographs of tree crowns to test whether the assessment methods for tree defoliation in Switzerland have changed over time. We randomly selected 24 series of slides of Norway spruce with field assessments made between 1986 and 1995. The slides were randomly arranged and assessed by three experts without prior knowledge of the year when the slide was taken or the tree number. Defoliation was assessed using the Swiss reference photo guide. Although the correlations between the field assessments and slide assessments were high (Spearman's rank correlation coefficient ranged between 0.79 and 0.83), we found significant differences between field and slide assessments (4.3 to 9% underprediction by the slide assessors) and between the slide assessments. However, no significant trends in field assessment methods could be detected. When the mean differences between field and slide assessments were subtracted, in some years, field assessors consistently underpredicted (1990, 1992) or overpredicted defoliation (1987, 1991). Defoliation tended to be overpredicted in slides taken against the light, and underpredicted for trees with more than 25% crown overlap. We conclude that slide series can be used to detect changes in assessment methods. However, potential observer bias calls for more objective methods of assessment.

Parkinsonia L.

Treesearch

Kristina F. Connor; Jane E. Rodgers; Carol Miller

2008-01-01

There are three noteworthy species of Parkinsonia grown in the United States. Palo verde is a thorny, green-barked shrub/small tree which can reach a height of 11 m. The name refers to the very noticeable green color of the smooth trunk of this drought-resistant tree of the hot southern deserts. The open-crowned trees have alternate, bipinnate...

Pruning open-grown black cherry

Treesearch

T. J. Grisez

1967-01-01

Black cherry trees that had large crown ratios and were 4 to 6 inches d. b. h. were pruned to various heights. Epicormic sprouting was severe and diameter growth at breast height was reduced on trees pruned to 75 percent of their height. Most trees pruned to 50 percent show little or no adverse effect after 3 years.

Other physical factors

Treesearch

John R. Jones; Norbert V. DeByle

1985-01-01

Aspen has been recognized for many years as being very intolerant of shade (Baker 1918a, Clements 1910, Weigle and Frothingham 1911, Zon and Graves 1911). In dense stands, vigorous aspen trees are confined to the dominant and codominant crown classes. Regardless of size, when they are overtopped by larger trees, aspen trees deteriorate and eventually die. Many well-...

Compartmentalization of pathogens in fire-injured trees

Treesearch

Kevin T. Smith

2013-01-01

Wildland fire is an episodic process that greatly influences the composition, structure, and developmental sequence of forests. Most news reports of wildland fire involves blazes fueled by slash, standing dead stems, and snags that reach into tree crowns and burn deeply into the forest floor, causing extensive tree mortality and the eventual replacement of the standing...

Best predictors for postfire mortality of ponderosa pine trees in the Intermountain West

Treesearch

Carolyn Hull Sieg; Joel D. McMillin; James F. Fowler; Kurt K. Allen; Jose F. Negron; Linda L. Wadleigh; John A. Anhold; Ken E. Gibson

2006-01-01

Numerous wildfires in recent years have highlighted managers' needs for reliable tools to predict postfire mortality of ponderosa pine (Pinus ponderosa Dougl. ex Laws.) trees. General applicability of existing mortality models is uncertain, as researchers have used different sets of variables. We quantified tree attributes, crown and bole fire...

Selecting superior yellow birch trees; a preliminary guide.

Treesearch

Knud E. Clausen; Richard M. Godman

1967-01-01

Describes procedures to follow and characteristics to consider in selecting superior yellow birch trees. The first selection should be on the basis of tree quality. Characteristics to consider are as follows: for the stem--straightness, roundness, taper grain, self-pruning, and absence of defects; for the crown--apical dominance, branch angle, and branch diameter;...

Key algorithms used in GR02: A computer simulation model for predicting tree and stand growth

Treesearch

Garrett A. Hughes; Paul E. Sendak; Paul E. Sendak

1985-01-01

GR02 is an individual tree, distance-independent simulation model for predicting tree and stand growth over time. It performs five major functions during each run: (1) updates diameter at breast height, (2) updates total height, (3) estimates mortality, (4) determines regeneration, and (5) updates crown class.

Spread of infection within tanoak (Lithocarpus densiflorus) trees inoculated with Phytophthora ramorum

Treesearch

J. Parke; B. Collins; G. Buckles; E. Hansen; B. Lachenbruch

2009-01-01

In an experiment with mature naturally infected tanoak trees, Phytophthora ramorum was observed in sapwood and appeared to interfere with stem water transport (Parke and others 2007). We postulated that colonization of the xylem could contribute to rapid spread within the tree and lead to development of crown mortality symptomatic of...

Tree Hydraulics: How Sap Rises

ERIC Educational Resources Information Center

Denny, Mark

2012-01-01

Trees transport water from roots to crown--a height that can exceed 100 m. The physics of tree hydraulics can be conveyed with simple fluid dynamics based upon the Hagen-Poiseuille equation and Murray's law. Here the conduit structure is modelled as conical pipes and as branching pipes. The force required to lift sap is generated mostly by…

Oak Growth and Response to Thinning

Treesearch

Stephen R. Shifley

2004-01-01

Oak growth and yield is simultaneously influenced by tree-, stand-, and landscape-scale factors. At the tree scale oak diameter growth varies by tree species (typically n. red oak >= scarlet oak > black oak > white oak > chestnut oak > chinkapin oak > post oak), but oak diameter growth is even more strongly influenced by crown class. Oak stands go...

Tradeoffs in basal area growth and reproduction shift over the lifetime of a long-lived tropical species.

PubMed

Staudhammer, Christina L; Wadt, Lúcia H O; Kainer, Karen A

2013-09-01

Understanding of the extent to which reproductive costs drive growth largely derives from reproductively mature temperate trees in masting and non-masting years. We modeled basal area increment (BAI) and explored current growth-reproduction tradeoffs and changes in such allocation over the life span of a long-lived, non-masting tropical tree. We integrated rainfall and soil variables with data from 190 Bertholletia excelsa trees of different diameter at breast height (DBH) sizes, crown characteristics, and liana loads, quantifying BAI and reproductive output over 4 and 6 years, respectively. While rainfall explains BAI in all models, regardless of DBH class or ontogenic stage, light (based on canopy position and crown form) is most critical in the juvenile (5 cm ≤ DBH < 50 cm) phase. Suppressed trees are only present as juveniles and grow ten times slower (1.45 ± 2.73 m(2) year(-1)) than trees in dominant and co-dominant positions (13.25 ± 0.82 and 12.90 ± 1.35 m(2) year(-1), respectively). Additionally, few juvenile trees are reproductive, and those that are, demonstrate reduced growth, as do reproductive trees in the next 50 to 100 cm DBH class, suggesting growth-reproduction tradeoffs. Upon reaching the canopy, however, and attaining a sizeable girth, this pattern gradually shifts to one where BAI and reproduction are influenced independently by variables such as liana load, crown size and soil properties. At this stage, BAI is largely unaffected by fruit production levels. Thus, while growth-reproduction tradeoffs clearly exist during early life stages, effects of reproductive allocation diminish as B. excelsa increases in size and maturity.

Early subtropical forest growth is driven by community mean trait values and functional diversity rather than the abiotic environment.

PubMed

Kröber, Wenzel; Li, Ying; Härdtle, Werner; Ma, Keping; Schmid, Bernhard; Schmidt, Karsten; Scholten, Thomas; Seidler, Gunnar; von Oheimb, Goddert; Welk, Erik; Wirth, Christian; Bruelheide, Helge

2015-09-01

While functional diversity (FD) has been shown to be positively related to a number of ecosystem functions including biomass production, it may have a much less pronounced effect than that of environmental factors or species-specific properties. Leaf and wood traits can be considered particularly relevant to tree growth, as they reflect a trade-off between resources invested into growth and persistence. Our study focussed on the degree to which early forest growth was driven by FD, the environment (11 variables characterizing abiotic habitat conditions), and community-weighted mean (CWM) values of species traits in the context of a large-scale tree diversity experiment (BEF-China). Growth rates of trees with respect to crown diameter were aggregated across 231 plots (hosting between one and 23 tree species) and related to environmental variables, FD, and CWM, the latter two of which were based on 41 plant functional traits. The effects of each of the three predictor groups were analyzed separately by mixed model optimization and jointly by variance partitioning. Numerous single traits predicted plot-level tree growth, both in the models based on CWMs and FD, but none of the environmental variables was able to predict tree growth. In the best models, environment and FD explained only 4 and 31% of variation in crown growth rates, respectively, while CWM trait values explained 42%. In total, the best models accounted for 51% of crown growth. The marginal role of the selected environmental variables was unexpected, given the high topographic heterogeneity and large size of the experiment, as was the significant impact of FD, demonstrating that positive diversity effects already occur during the early stages in tree plantations.

Ensemble classification of individual Pinus crowns from multispectral satellite imagery and airborne LiDAR

NASA Astrophysics Data System (ADS)

Kukunda, Collins B.; Duque-Lazo, Joaquín; González-Ferreiro, Eduardo; Thaden, Hauke; Kleinn, Christoph

2018-03-01

Distinguishing tree species is relevant in many contexts of remote sensing assisted forest inventory. Accurate tree species maps support management and conservation planning, pest and disease control and biomass estimation. This study evaluated the performance of applying ensemble techniques with the goal of automatically distinguishing Pinus sylvestris L. and Pinus uncinata Mill. Ex Mirb within a 1.3 km2 mountainous area in Barcelonnette (France). Three modelling schemes were examined, based on: (1) high-density LiDAR data (160 returns m-2), (2) Worldview-2 multispectral imagery, and (3) Worldview-2 and LiDAR in combination. Variables related to the crown structure and height of individual trees were extracted from the normalized LiDAR point cloud at individual-tree level, after performing individual tree crown (ITC) delineation. Vegetation indices and the Haralick texture indices were derived from Worldview-2 images and served as independent spectral variables. Selection of the best predictor subset was done after a comparison of three variable selection procedures: (1) Random Forests with cross validation (AUCRFcv), (2) Akaike Information Criterion (AIC) and (3) Bayesian Information Criterion (BIC). To classify the species, 9 regression techniques were combined using ensemble models. Predictions were evaluated using cross validation and an independent dataset. Integration of datasets and models improved individual tree species classification (True Skills Statistic, TSS; from 0.67 to 0.81) over individual techniques and maintained strong predictive power (Relative Operating Characteristic, ROC = 0.91). Assemblage of regression models and integration of the datasets provided more reliable species distribution maps and associated tree-scale mapping uncertainties. Our study highlights the potential of model and data assemblage at improving species classifications needed in present-day forest planning and management.

Early subtropical forest growth is driven by community mean trait values and functional diversity rather than the abiotic environment

PubMed Central

Kröber, Wenzel; Li, Ying; Härdtle, Werner; Ma, Keping; Schmid, Bernhard; Schmidt, Karsten; Scholten, Thomas; Seidler, Gunnar; von Oheimb, Goddert; Welk, Erik; Wirth, Christian; Bruelheide, Helge

2015-01-01

While functional diversity (FD) has been shown to be positively related to a number of ecosystem functions including biomass production, it may have a much less pronounced effect than that of environmental factors or species-specific properties. Leaf and wood traits can be considered particularly relevant to tree growth, as they reflect a trade-off between resources invested into growth and persistence. Our study focussed on the degree to which early forest growth was driven by FD, the environment (11 variables characterizing abiotic habitat conditions), and community-weighted mean (CWM) values of species traits in the context of a large-scale tree diversity experiment (BEF-China). Growth rates of trees with respect to crown diameter were aggregated across 231 plots (hosting between one and 23 tree species) and related to environmental variables, FD, and CWM, the latter two of which were based on 41 plant functional traits. The effects of each of the three predictor groups were analyzed separately by mixed model optimization and jointly by variance partitioning. Numerous single traits predicted plot-level tree growth, both in the models based on CWMs and FD, but none of the environmental variables was able to predict tree growth. In the best models, environment and FD explained only 4 and 31% of variation in crown growth rates, respectively, while CWM trait values explained 42%. In total, the best models accounted for 51% of crown growth. The marginal role of the selected environmental variables was unexpected, given the high topographic heterogeneity and large size of the experiment, as was the significant impact of FD, demonstrating that positive diversity effects already occur during the early stages in tree plantations. PMID:26380685

Mechanisms of Douglas-fir resistance to western spruce budworm defoliation: bud burst phenology, photosynthetic compensation and growth rate.

PubMed

Chen, Z; Kolb, T E; Clancy, K M

2001-10-01

We compared growth rates among mature interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) trees showing resistance or susceptibility to defoliation caused by western spruce budworm (Choristoneura occidentalis Freeman), and among clones and half-sib seedling progeny of these trees in a greenhouse. We also investigated bud burst phenology and photosynthetic responses of clones to budworm defoliation in greenhouse experiments. Resistant mature trees had a higher radial growth rate than susceptible trees, especially during periods of budworm defoliation. Clones from resistant trees grew larger crowns than clones from susceptible trees, whereas stem base diameter at the ground line and height did not differ. Half-sib seedling progeny from resistant trees had larger stem diameter, height, and total biomass than progeny from susceptible trees. Mean 5-year radial growth increment of mature trees was more strongly correlated with growth of seedlings than with growth of clones. Clones from resistant trees had later bud burst than clones from susceptible trees, and budworm defoliation of clones depended on the degree of synchrony between bud burst phenology and budworm larval feeding. Clones of resistant and susceptible mature trees showed similar responses of net photosynthetic rate to 2 years of budworm defoliation. We conclude that phenotypic differences in crown condition of Douglas-fir trees following western spruce budworm defoliation are influenced by tree genotype and that high growth rate and late bud burst phenology promote tree resistance to budworm defoliation.

Critical mass flux for flaming ignition of dead, dry wood as a function of external radiant heat flux and oxidizer flow velocity

Treesearch

Sara McAllister; Mark Finney; Jack Cohen

2010-01-01

Extreme weather often contributes to crown fires, where the fire spreads from one tree crown to the next as a series of piloted ignitions. An important aspect in predicting crown fires is understanding the ignition of fuel particles. The ignition criterion considered in this work is the critical mass flux criterion – that a sufficient amount of pyrolysis gases must be...

Effects of branch height on leaf gas exchange, branch hydraulic conductance and branch sap flux in open-grown ponderosa pine.

PubMed

Hubbard, Robert M; Bond, Barbara J; Senock, Randy S; Ryan, Michael G

2002-06-01

Recent studies have shown that stomata respond to changes in hydraulic conductance of the flow path from soil to leaf. In open-grown tall trees, branches of different heights may have different hydraulic conductances because of differences in path length and growth. We determined if leaf gas exchange, branch sap flux, leaf specific hydraulic conductance, foliar carbon isotope composition (delta13C) and ratios of leaf area to sapwood area within branches were dependent on branch height (10 and 25 m) within the crowns of four open-grown ponderosa pine (Pinus ponderosa Laws.) trees. We found no difference in leaf gas exchange or leaf specific hydraulic conductance from soil to leaf between the upper and lower canopy of our study trees. Branch sap flux per unit leaf area and per unit sapwood area did not differ between the 10- and 25-m canopy positions; however, branch sap flux per unit sapwood area at the 25-m position had consistently lower values. Branches at the 25-m canopy position had lower leaf to sapwood area ratios (0.17 m2 cm-2) compared with branches at the 10-m position (0.27 m2 cm-2) (P = 0.03). Leaf specific conductance of branches in the upper crown did not differ from that in the lower crown. Other studies at our site indicate lower hydraulic conductance, sap flux, whole-tree canopy conductance and photosynthesis in old trees compared with young trees. This study suggests that height alone may not explain these differences.

Applying a crop-tree release in small-sawtimber white oak stands

Treesearch

Jeffrey W Stringer; Gary W. Miller; Robert F. Wittwer; Robert F. Wittwer

1988-01-01

Small-sawtimber white oak crop trees in Kentucky were released by a crown-touching technique. In two cutting treatments, 20 and 34 crop trees were released per acre at a total cost of $35 and $42, respectively. Both treatments yielded commercial volumes of cut material. Total mean merchantable volume (> 5.0 inches d.b.h.) in cut trees was 693 cubic feet/acre, with...

A method for locating potential tree-planting sites in urban areas: a case study of Los Angeles, USA

Treesearch

Chunxia Wua; Qingfu Xiaoa; Gregory E. McPherson

2008-01-01

A GIS-based method for locating potential tree-planting sites based on land cover data is introduced. Criteria were developed to identify locations that are spatially available for potential tree planting based on land cover, sufficient distance from impervious surfaces, a minimum amount of pervious surface, and no crown overlap with other trees. In an ArcGIS...

Mapping Urban Tree Canopy Coverage and Structure using Data Fusion of High Resolution Satellite Imagery and Aerial Lidar

NASA Astrophysics Data System (ADS)

Elmes, A.; Rogan, J.; Williams, C. A.; Martin, D. G.; Ratick, S.; Nowak, D.

2015-12-01

Urban tree canopy (UTC) coverage is a critical component of sustainable urban areas. Trees provide a number of important ecosystem services, including air pollution mitigation, water runoff control, and aesthetic and cultural values. Critically, urban trees also act to mitigate the urban heat island (UHI) effect by shading impervious surfaces and via evaporative cooling. The cooling effect of urban trees can be seen locally, with individual trees reducing home HVAC costs, and at a citywide scale, reducing the extent and magnitude of an urban areas UHI. In order to accurately model the ecosystem services of a given urban forest, it is essential to map in detail the condition and composition of these trees at a fine scale, capturing individual tree crowns and their vertical structure. This paper presents methods for delineating UTC and measuring canopy structure at fine spatial resolution (<1m). These metrics are essential for modeling the HVAC benefits from UTC for individual homes, and for assessing the ecosystem services for entire urban areas. Such maps have previously been made using a variety of methods, typically relying on high resolution aerial or satellite imagery. This paper seeks to contribute to this growing body of methods, relying on a data fusion method to combine the information contained in high resolution WorldView-3 satellite imagery and aerial lidar data using an object-based image classification approach. The study area, Worcester, MA, has recently undergone a large-scale tree removal and reforestation program, following a pest eradication effort. Therefore, the urban canopy in this location provides a wide mix of tree age class and functional type, ideal for illustrating the effectiveness of the proposed methods. Early results show that the object-based classifier is indeed capable of identifying individual tree crowns, while continued research will focus on extracting crown structural characteristics using lidar-derived metrics. Ultimately, the resulting fine resolution UTC map will be compared with previously created UTC maps of the same area but for earlier dates, producing a canopy change map corresponding to the Worcester area tree removal and replanting effort.

Canopy area of large trees explains aboveground biomass variations across neotropical forest landscapes

NASA Astrophysics Data System (ADS)

Meyer, Victoria; Saatchi, Sassan; Clark, David B.; Keller, Michael; Vincent, Grégoire; Ferraz, António; Espírito-Santo, Fernando; d'Oliveira, Marcus V. N.; Kaki, Dahlia; Chave, Jérôme

2018-06-01

Large tropical trees store significant amounts of carbon in woody components and their distribution plays an important role in forest carbon stocks and dynamics. Here, we explore the properties of a new lidar-derived index, the large tree canopy area (LCA) defined as the area occupied by canopy above a reference height. We hypothesize that this simple measure of forest structure representing the crown area of large canopy trees could consistently explain the landscape variations in forest volume and aboveground biomass (AGB) across a range of climate and edaphic conditions. To test this hypothesis, we assembled a unique dataset of high-resolution airborne light detection and ranging (lidar) and ground inventory data in nine undisturbed old-growth Neotropical forests, of which four had plots large enough (1 ha) to calibrate our model. We found that the LCA for trees greater than 27 m (˜ 25-30 m) in height and at least 100 m2 crown size in a unit area (1 ha), explains more than 75 % of total forest volume variations, irrespective of the forest biogeographic conditions. When weighted by average wood density of the stand, LCA can be used as an unbiased estimator of AGB across sites (R2 = 0.78, RMSE = 46.02 Mg ha-1, bias = -0.63 Mg ha-1). Unlike other lidar-derived metrics with complex nonlinear relations to biomass, the relationship between LCA and AGB is linear and remains unique across forest types. A comparison with tree inventories across the study sites indicates that LCA correlates best with the crown area (or basal area) of trees with diameter greater than 50 cm. The spatial invariance of the LCA-AGB relationship across the Neotropics suggests a remarkable regularity of forest structure across the landscape and a new technique for systematic monitoring of large trees for their contribution to AGB and changes associated with selective logging, tree mortality and other types of tropical forest disturbance and dynamics.

Forest Health Monitoring in New Hampshire, 1996-1999

Treesearch

Northeastern Research Station

2002-01-01

New Hampshire has mature forests dominated by hardwood species but with significant softwood resources. The majority of the trees are healthy with full crowns (low transparency, high density), little dieback and little damage. Red maple had higher dieback and more damage than other species. Eastern white pine had lower crown densities and little damage.

CROWN GALL INCIDENCE: SEEDLING PARADOX WALNUT ROOTSTOCK VERSUS OWN-ROOTED ENGLISH WALNUT TREES

USDA-ARS?s Scientific Manuscript database

Seedling Paradox (Juglans hindsii x J. regia) has been the rootstock of choice for English walnut in California because of its vigor and greater tolerance of wet soil conditions. However, seedling Paradox rootstock is highly susceptible to crown gall, a disease caused by the soil-borne bacterium Agr...

Estimating aspen crown fuels in northeastern Minnesota.

Treesearch

Robert M. Loomis; Peter J. Roussopoulos

1978-01-01

An application section presents tables for estimating foliage and branchwood (wood plus bark) of aspen tree crowns; the branchwood is subdivided by (1) living and dead material and by (2) living material alone into diameter size groups. A documentation section describes the derivation of equations and compares the equations derived with those derived by other...

Assessing crown dynamics and inter-tree competition in southern pines

Treesearch

Timothy A. Martin; Angelica Garcia; Tania Quesada; Eric J. Jokela; Salvador Gezan

2015-01-01

Genetic improvement of southern pines has been underway for 50 years and during this time, deployment of germplasm has generally evolved from more genetically diverse to less genetically diverse. Information is needed on how deployment of individual genotypes in pure blocks will affect traits such as within-stand variation in individual tree traits, as well as tree-...

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....

Stocking guidelines for the endemic Hawaiian hardwood, Acacia koa

Treesearch

P. J. Baker; P. G. Scowcroft

2005-01-01

Stocking relationships are an important tool for foresters because they provide a means for evaluating how effectively the trees in a stand use available growing space. While stocking guidelines are not available for many tropical tree species, readily obtained measurements of stem and crown diameters can be used to develop preliminary stocking guidelines for most tree...

The feasibility of remotely sensed data to estimate urban tree dimensions and biomass

Treesearch

Jun-Hak Lee; Yekang Ko; E. Gregory McPherson

2016-01-01

Accurately measuring the biophysical dimensions of urban trees, such as crown diameter, stem diameter, height, and biomass, is essential for quantifying their collective benefits as an urban forest. However, the cost of directly measuring thousands or millions of individual trees through field surveys can be prohibitive. Supplementing field surveys with remotely sensed...

Relationships between tree height and carbon isotope discrimination

Treesearch

Nate G. McDowell; Barbara J. Bond; Lee T. Dickman; Michael G. Ryan; David Whitehead

2011-01-01

Understanding how tree size impacts leaf- and crown-level gas exchange is essential to predicting forest yields and carbon and water budgets. The stable carbon isotope ratio of organic matter has been used to examine the relationship of gas exchange to tree size for a host of species because it carries a temporally integrated signature of foliar photosynthesis and...

Partial shading of lateral branches affects growth, and foliage nitrogen- and water-use efficiencies in the conifer Cunninghamia lanceolata growing in a warm monsoon climate.

PubMed

Dong, Tingfa; Li, Junyu; Zhang, Yuanbin; Korpelainen, Helena; Niinemets, Ülo; Li, Chunyang

2015-06-01

The degree to which branches are autonomous in their acclimation responses to alteration in light environment is still poorly understood. We investigated the effects of shading of the sapling crown of Cunninghamia lanceolata (Lamb.) Hook on the whole-tree and mid-crown branch growth and current-year foliage structure and physiology. Four treatments providing 0, 50, 75 and 90% shading compared with full daylight (denoted as Treatment(0), Treatment(50%), Treatment(75%) and Treatment(90%), and Shaded(0), Shaded(50%), Shaded(75%) and Shaded(90%) for the shaded branches and Sunlit(0), Sunlit(50%), Sunlit(75%) and Sunlit(90%) for the opposite sunlit branches under natural light conditions, respectively), were applied over two consecutive growing seasons. Shading treatments decreased the growth of basal stem diameter, leaf dry mass per unit leaf area, stomatal conductance, transpiration rate, the ratio of water-soluble to structural leaf nitrogen content, photosynthetic nitrogen-use efficiency and instantaneous and long-term (estimated from carbon isotope composition) water-use efficiency in shaded branches. Differences between shaded and sunlit branches increased with increasing severity and duration of shading. A non-autonomous, partly compensatory behavior of non-shaded branches was observed for most traits, thus reflecting the dependence between the traits of sunlit branches and the severity of shading of the opposite crown half. The results collectively indicated that tree growth and branch and leaf acclimation responses of C. lanceolata are not only affected by the local light environment, but also by relative within-crown light conditions. We argue that such a non-autonomous branch response to changes in light conditions can improve whole-tree resource optimization. These results contribute to better understanding of tree growth and utilization of water and nitrogen under heterogeneous light conditions within tree canopies. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Tree-crown-resolving large-eddy simulation for evaluating greenery effects on urban heat environments

NASA Astrophysics Data System (ADS)

Matsuda, K.; Onishi, R.; Takahashi, K.

2017-12-01

Urban high temperatures due to the combined influence of global warming and urban heat islands increase the risk of heat stroke. Greenery is one of possible countermeasures for mitigating the heat environments since the transpiration and shading effect of trees can reduce the air temperature and the radiative heat flux. In order to formulate effective measures, it is important to estimate the influence of the greenery on the heat stroke risk. In this study, we have developed a tree-crown-resolving large-eddy simulation (LES) model that is coupled with three-dimensional radiative transfer (3DRT) model. The Multi-Scale Simulator for the Geoenvironment (MSSG) is used for performing building- and tree-crown-resolving LES. The 3DRT model is implemented in the MSSG so that the 3DRT is calculated repeatedly during the time integration of the LES. We have confirmed that the computational time for the 3DRT model is negligibly small compared with that for the LES and the accuracy of the 3DRT model is sufficiently high to evaluate the radiative heat flux at the pedestrian level. The present model is applied to the analysis of the heat environment in an actual urban area around the Tokyo Bay area, covering 8 km × 8 km with 5-m grid mesh, in order to confirm its feasibility. The results show that the wet-bulb globe temperature (WBGT), which is an indicator of the heat stroke risk, is predicted in a sufficiently high accuracy to evaluate the influence of tree crowns on the heat environment. In addition, by comparing with a case without the greenery in the Tokyo Bay area, we have confirmed that the greenery increases the low WBGT areas in major pedestrian spaces by a factor of 3.4. This indicates that the present model can predict the greenery effect on the urban heat environment quantitatively.

Quantifying pruning impacts on olive tree architecture and annual canopy growth by using UAV-based 3D modelling.

PubMed

Jiménez-Brenes, F M; López-Granados, F; de Castro, A I; Torres-Sánchez, J; Serrano, N; Peña, J M

2017-01-01

Tree pruning is a costly practice with important implications for crop harvest and nutrition, pest and disease control, soil protection and irrigation strategies. Investigations on tree pruning usually involve tedious on-ground measurements of the primary tree crown dimensions, which also might generate inconsistent results due to the irregular geometry of the trees. As an alternative to intensive field-work, this study shows a innovative procedure based on combining unmanned aerial vehicle (UAV) technology and advanced object-based image analysis (OBIA) methodology for multi-temporal three-dimensional (3D) monitoring of hundreds of olive trees that were pruned with three different strategies (traditional, adapted and mechanical pruning). The UAV images were collected before pruning, after pruning and a year after pruning, and the impacts of each pruning treatment on the projected canopy area, tree height and crown volume of every tree were quantified and analyzed over time. The full procedure described here automatically identified every olive tree on the orchard and computed their primary 3D dimensions on the three study dates with high accuracy in the most cases. Adapted pruning was generally the most aggressive treatment in terms of the area and volume (the trees decreased by 38.95 and 42.05% on average, respectively), followed by trees under traditional pruning (33.02 and 35.72% on average, respectively). Regarding the tree heights, mechanical pruning produced a greater decrease (12.15%), and these values were minimal for the other two treatments. The tree growth over one year was affected by the pruning severity and by the type of pruning treatment, i.e., the adapted-pruning trees experienced higher growth than the trees from the other two treatments when pruning intensity was low (<10%), similar to the traditionally pruned trees at moderate intensity (10-30%), and lower than the other trees when the pruning intensity was higher than 30% of the crown volume. Combining UAV-based images and an OBIA procedure allowed measuring tree dimensions and quantifying the impacts of three different pruning treatments on hundreds of trees with minimal field work. Tree foliage losses and annual canopy growth showed different trends as affected by the type and severity of the pruning treatments. Additionally, this technology offers valuable geo-spatial information for designing site-specific crop management strategies in the context of precision agriculture, with the consequent economic and environmental benefits.

Crown traits of coniferous trees and their relation to shade tolerance can differ with leaf type: a biophysical demonstration using computed tomography scanning data.

PubMed

Dutilleul, Pierre; Han, Liwen; Valladares, Fernando; Messier, Christian

2015-01-01

Plant light interception and shade tolerance are intrinsically related in that they involve structural, morphological and physiological adaptations to manage light capture for photosynthetic utilization, in order to sustain survival, development and reproduction. At the scale of small-size trees, crown traits related to structural geometry of branching pattern and space occupancy through phyllotaxis can be accurately evaluated in 3D, using computed tomography (CT) scanning data. We demonstrate this by scrutinizing the crowns of 15 potted miniature conifers of different species or varieties, classified in two groups based on leaf type (10 needlelike, 5 scalelike); we also test whether mean values of crown traits measured from CT scanning data and correlations with a shade tolerance index (STI) differ between groups. Seven crown traits, including fractal dimensions (FD1: smaller scales, FD2: larger scales) and leaf areas, were evaluated for all 15 miniature conifers; an average silhouette-to-total-area ratio was also calculated for each of the 10 needlelike-leaf conifers. Between-group differences in mean values are significant (P < 0.05) for STI, FD1, FD2, and the average leaf area displayed (ĀD). Between-group differences in sign and strength of correlations are observed. For example, the correlation between STI and FD1 is negative and significant (P < 0.10) for the needlelike-leaf group, but is positive and significant (P < 0.05) for the miniature conifers with scalelike leaves, which had lower STI and higher FD1 on average in our study; the positive correlation between STI and ĀD is significant (P < 0.05) for the scalelike-leaf group, and very moderate for the needlelike-leaf one. A contrasting physical attachment of the leaves to branches may explain part of the between-group differences. Our findings open new avenues for the understanding of fundamental plant growth processes; the information gained could be included in a multi-scale approach to tree crown modeling.

Predicting diameter at breast height from total height and crown length

Treesearch

Quang V. Cao; Thomas J. Dean

2013-01-01

Tree diameter at breast height (d.b.h.) is often predicted from total height (model 1a) or both total height and number of trees per acre (model 1b). These approaches are useful when Light Detection and Ranging (LiDAR) data are available. LiDAR height data can be employed to predict tree d.b.h., and consequently individual tree volumes and volume/ ha can be obtained...

Changes in tree density do not influence epicormic branching of yellow-poplar

Treesearch

H. Clay Smith

1977-01-01

Epicormic branching was studied in a West Virginia yellow-poplar stand thinned to various tree density levels. Study trees in the 55- to 60-year-old second-growth stand were primarily codominant in crown class with 32 to 48 feet of log height. Eight-year study results indicated that yellow-poplar trees in this age class and locale could be thinned without serious loss...

Nervous systems and scenarios for the invertebrate-to-vertebrate transition

PubMed Central

Holland, Nicholas D.

2016-01-01

Older evolutionary scenarios for the origin of vertebrates often gave nervous systems top billing in accordance with the notion that a big-brained Homo sapiens crowned a tree of life shaped mainly by progressive evolution. Now, however, tree thinking positions all extant organisms equidistant from the tree's root, and molecular phylogenies indicate that regressive evolution is more common than previously suspected. Even so, contemporary theories of vertebrate origin still focus on the nervous system because of its functional importance, its richness in characters for comparative biology, and its central position in the two currently prominent scenarios for the invertebrate-to-vertebrate transition, which grew out of the markedly neurocentric annelid and enteropneust theories of the nineteenth century. Both these scenarios compare phyla with diverse overall body plans. This diversity, exacerbated by the scarcity of relevant fossil data, makes it challenging to establish plausible homologies between component parts (e.g. nervous system regions). In addition, our current understanding of the relation between genotype and phenotype is too preliminary to permit us to convert gene network data into structural features in any simple way. These issues are discussed here with special reference to the evolution of nervous systems during proposed transitions from invertebrates to vertebrates. PMID:26598728

Managing for Climate Change Adaptation in Forests: a Case Study from the U.S. Southwest

NASA Astrophysics Data System (ADS)

Kerhoulas, L. P.; Kolb, T.; Koch, G. W.; Hurteau, M. D.

2016-12-01

Forest mortality related to climate change is an increasingly common global phenomenon. We provide a case study of the U.S. Southwest to investigate the interactions among forest restoration treatments that alter stand density, tree growth, and drought resistance in trees of different size classes. Using cores taken from five positions in large trees (coarse roots, breast height, base of live crown, mid-crown branch, and treetop) and breast height in small trees, we investigated how radial growth response to thinning and precipitation availability varied in 72 ponderosa pines Pinus ponderosa Dougl. in northern Arizona. Ten years after thinning, growth of small trees did not respond significantly to thinning whereas growth of large trees increased following moderate and heaving thinning, and this response was similar across within-tree core sample positions. The intensity of thinning treatment did not significantly affect dry-year growth in small trees. In large trees, dry-year growth after thinning was maintained at pre-thinning levels in moderate and heavy thinning treatments but decreased in the light thinning and control treatments. Our findings indicate that more aggressive thinning treatments used for forest restoration stimulate growth throughout large residual trees from coarse roots to branches and also improve drought resistance, providing a greater resilience to future climate-related stress. These responses to treatment are more pronounced in large trees than small trees. Forest thinning is therefore recommended in systems that are likely to experience increased temperature and decreased precipitation as a result of climate change.

Stimulating seedling growth in early stages of secondary forest succession: a modeling approach to guide tree liberation

PubMed Central

van Kuijk, Marijke; Anten, Niels P. R.; Oomen, Roelof J.; Schieving, Feike

2014-01-01

Excessive growth of non-woody plants and shrubs on degraded lands can strongly hamper tree growth and thus secondary forest succession. A common method to accelerate succession, called liberation, involves opening up the vegetation canopy around young target trees. This can increase growth of target trees by reducing competition for light with neighboring plants. However, liberation has not always had the desired effect, likely due to differences in light requirement between tree species. Here we present a 3D-model, which calculates photosynthetic rate of individual trees in a vegetation stand. It enables us to examine how stature, crown structure, and physiological traits of target trees and characteristics of the surrounding vegetation together determine effects of light on tree growth. The model was applied to a liberation experiment conducted with three pioneer species in a young secondary forest in Vietnam. Species responded differently to the treatment depending on their height, crown structure and their shade-tolerance level. Model simulations revealed practical thresholds over which the tree growth response is heavily influenced by the height and density of surrounding vegetation and gap radius. There were strong correlations between calculated photosynthetic rates and observed growth: the model was well able to predict growth of trees in young forests and the effects of liberation there upon. Thus, our model serves as a useful tool to analyze light competition between young trees and surrounding vegetation and may help assess the potential effect of tree liberation. PMID:25101100

A study on crown interception with four dominant tree species: a direct measurement

Treesearch

Xiang Li; Jianzhi Niu; Linus Zhang; Qingfu Xiao; Gregory E. McPherson; Natalie van Doorn; Xinxiao Yu; Baoyuan Xie; Salli Dymond; Jiao Li; Chen Meng; Ziteng Luo

2016-01-01

An experiment was conducted to concentrate on the rainfall interception process of individual trees for four common species in Beijing, China, which included needle species (Platycladus orientalis and Pinus tabulaeformis) and broadleaf species (Quercus variabilis and Acer truncatum)....

Forest Health Monitoring in Maine, 1996-1999.

Treesearch

Northeastern Research Station

2002-01-01

Maine has mixed-age forests dominated by softwood species. Most of the trees are healthy, with full crowns (low transparency, high density), little dieback and little damage. Red maple had higher amounts of dieback but seemed to maintain crown fullness. Eastern white pine and northern white cedar had lower densities as well as higher rates of damage.

Three scales of aerial photography compared for making stand measurements

Treesearch

Earl J. Rogers; Gene Avery; Roy A. Chapman

1959-01-01

Three scales of aerial photography were tested in an attempt to determine the best scale to use in forest surveying. This was done by comparing photo measurements of average tree height, average crown diameter, and crown-closure percent. These stand variables were selected for testing because of their applicability in making aerial estimates of timber volume.

Forest Health Monitoring in Connecticut, 1996-1999

Treesearch

Northeastern Research Station

2002-01-01

Connecticut has mature forests dominated by hardwoods. Most trees are healthy with full crowns (low transparency and high density), little dieback and little damage. The exception is eastern hemlock, which was in poor condition, with thin crowns, more dieback and more damage, especially broken tops. These conditions are likely the result of attack by the hemlock woolly...

Forest Health Monitoring in New York, 1996-1999

Treesearch

Northeastern Research Station

2002-01-01

New York has mature forests dominated by hardwood species, but with a significant and varied softwood resource. Most of the trees are healthy, with full crowns (low transparency, high density), little dieback and little damage. American beech tends to be in poorer condition, with thin crowns, higher dieback, and more damage, especially broken and dead branches.

Use of Direct and Indirect Estimates of Crown Dimensions to Predict One Seed Juniper Woody Biomass Yield for Alternative Energy Uses

USDA-ARS?s Scientific Manuscript database

Throughout the western United States there is increased interest in utilizing woodland biomass as an alternative energy source. We conducted a pilot study to predict one seed juniper (Juniperus monosperma) chip yield from tree-crown dimensions measured on the ground or derived from Very Large Scale ...

Apical bud toughness tests and tree sway movements to examine crown abrasion: preliminary results

Treesearch

Tyler Brannon; Wayne Clatterbuck

2012-01-01

Apical bud toughness differences were examined for several species to determine if crown abrasion affects shoot growth of determinate and indeterminate species during stand development. Determinate buds will set and harden after initial shoot elongation in the spring, while the indeterminate shoots form leaves from the apical meristem continuously based on the...

Comparison of Field Methods and Models to Estimate Mean Crown Diameter

Treesearch

William A. Bechtold; Manfred E. Mielke; Stanley J. Zarnoch

2002-01-01

The direct measurement of crown diameters with logger's tapes adds significantly to the cost of extensive forest inventories. We undertook a study of 100 trees to compare this measurement method to four alternatives-two field instruments, ocular estimates, and regression models. Using the taping method as the standard of comparison, accuracy of the tested...

Root-infecting fungi associated with a decline of longleaf pine in the southeastern United States

Treesearch

William J. Otrosina; Diane Bannwart; Ronald W. Roncadori

1999-01-01

A 35-year-old longleaf pine stand exhibited trees in various stages of decline. A study was conducted to determine root-infecting fungi and other abnormalities associated with varying degrees of crown symptoms. A four-class crown symptom rating system was devised according to ascending symptom severity. Leptographium procerum and L....

Multiple Ceratocystis smalleyi infections associated with reduced stem water transport in bitternut hickory.

PubMed

Park, J-H; Juzwik, J; Cavender-Bares, J

2013-06-01

Hundreds of cankers caused by Ceratocystis smalleyi are associated with hickory bark beetle-attacked bitternut hickory exhibiting rapid crown decline in the north-central and northeastern United States. Discolored sapwood colonized by the fungus commonly underlies the cankers. Field studies were conducted to test the hypothesis that C. smalleyi infections cause vascular system dysfunction in infected trees. Fifty C. smalleyi inoculations made at 1.8 to 3.8 m in height on stems of healthy bitternut hickory trees (13 to 28 cm in diameter at 1.4 m in height) resulted in extensive canker formation and sapwood discoloration 12 to 14 months after treatment compared with water-inoculated and noninoculated controls. Sap flow velocity (midday) was significantly lower in the infected trees compared with that in the controls. Sap flow velocity also was inversely correlated with the proportion of bark area with cankered tissues and with tylose abundance in the youngest two growth rings. Tylose formation in current-year vessels associated with C. smalleyi infections is likely responsible for much of the water transport disruption. It is hypothesized that multiple stem infections of C. smalleyi and the resulting xylem dysfunction contribute to crown wilt development in bitternut hickory exhibiting rapid crown decline.

MODIS Tree Cover Validation for the Circumpolar Taiga-Tundra Transition Zone

NASA Technical Reports Server (NTRS)

Montesano, P. M.; Nelson, R.; Sun, G.; Margolis, H.; Kerber, A.; Ranson, K. J.

2009-01-01

A validation of the 2005 500m MODIS vegetation continuous fields (VCF) tree cover product in the circumpolar taiga-tundra ecotone was performed using high resolution Quickbird imagery. Assessing the VCF's performance near the northern limits of the boreal forest can help quantify the accuracy of the product within this vegetation transition area. The circumpolar region was divided into longitudinal zones and validation sites were selected in areas of varying tree cover where Quickbird imagery is available in Google Earth. Each site was linked to the corresponding VCF pixel and overlaid with a regular dot grid within the VCF pixel's boundary to estimate percent tree crown cover in the area. Percent tree crown cover was estimated using Quickbird imagery for 396 sites throughout the circumpolar region and related to the VCF's estimates of canopy cover for 2000-2005. Regression results of VCF inter-annual comparisons (2000-2005) and VCF-Quickbird image-interpreted estimates indicate that: (1) Pixel-level, inter-annual comparisons of VCF estimates of percent canopy cover were linearly related (mean R(sup 2) = 0.77) and exhibited an average root mean square error (RMSE) of 10.1 % and an average root mean square difference (RMSD) of 7.3%. (2) A comparison of image-interpreted percent tree crown cover estimates based on dot counts on Quickbird color images by two different interpreters were more variable (R(sup 2) = 0.73, RMSE = 14.8%, RMSD = 18.7%) than VCF inter-annual comparisons. (3) Across the circumpolar boreal region, 2005 VCF-Quickbird comparisons were linearly related, with an R(sup 2) = 0.57, a RMSE = 13.4% and a RMSD = 21.3%, with a tendency to over-estimate areas of low percent tree cover and anomalous VCF results in Scandinavia. The relationship of the VCF estimates and ground reference indicate to potential users that the VCF's tree cover values for individual pixels, particularly those below 20% tree cover, may not be precise enough to monitor 500m pixel-level tree cover in the taiga-tundra transition zone.

Large old trees influence patterns of delta13C and delta15N in forests.

PubMed

Weber, Pascale; Bol, Roland; Dixon, Liz; Bardgett, Richard D

2008-06-01

Large old trees are the dominant primary producers of native pine forest, but their influence on spatial patterns of soil properties and potential feedback to tree regeneration in their neighbourhood is poorly understood. We measured stable isotopes of carbon (delta(13)C) and nitrogen (delta(15)N) in soil and litter taken from three zones of influence (inner, middle and outer zone) around the trunk of freestanding old Scots pine (Pinus sylvestris L.) trees, to determine the trees' influence on below-ground properties. We also measured delta(15)N and delta(13)C in wood cores extracted from the old trees and from regenerating trees growing within their three zones of influence. We found a significant and positive gradient in soil delta(15)N from the inner zone, nearest to the tree centre, to the outer zone beyond the tree crown. This was probably caused by the higher input of (15)N-depleted litter below the tree crown. In contrast, the soil delta(13)C did not change along the gradient of tree influence. Distance-related trends, although weak, were visible in the wood delta(15)N and delta(13)C of regenerating trees. Moreover, the wood delta(15)N of small trees showed a weak negative relationship with soil N content in the relevant zone of influence. Our results indicate that large old trees control below-ground conditions in their immediate surroundings, and that stable isotopes might act as markers for the spatial and temporal extent of these below-ground effects. John Wiley & Sons, Ltd

Responses of Tree Growths to Tree Size, Competition, and Topographic Conditions in Sierra Nevada Forests Using Bi-temporal Airborne LiDAR Data

NASA Astrophysics Data System (ADS)

Ma, Q.; Su, Y.; Tao, S.; Guo, Q.

2016-12-01

Trees in the Sierra Nevada (SN) forests are experiencing rapid changes due to human disturbances and climatic changes. An improved monitoring of tree growth and understanding of how tree growth responses to different impact factors, such as tree competition, forest density, topographic and hydrologic conditions, are urgently needed in tree growth modeling. Traditional tree growth modeling mainly relied on field survey, which was highly time-consuming and labor-intensive. Airborne Light detection and ranging System (ALS) is increasingly used in forest survey, due to its high efficiency and accuracy in three-dimensional tree structure delineation and terrain characterization. This study successfully detected individual tree growth in height (ΔH), crown area (ΔA), and crown volume (ΔV) over a five-year period (2007-2012) using bi-temporal ALS data in two conifer forest areas in SN. We further analyzed their responses to original tree size, competition indices, forest structure indices, and topographic environmental parameters at individual tree and forest stand scales. Our results indicated ΔH was strongly sensitive to topographic wetness index; whereas ΔA and ΔV were highly responsive to forest density and original tree sizes. These ALS based findings in ΔH were consistent with field measurements. Our study demonstrated the promising potential of using bi-temporal ALS data in forest growth measurements and analysis. A more comprehensive study over a longer temporal period and a wider range of forest stands would give better insights into tree growth in the SN, and provide useful guides for forest growth monitoring, modeling, and management.

Relating FIA data to habitat classifications via tree-based models of canopy cover

Treesearch

Mark D. Nelson; Brian G. Tavernia; Chris Toney; Brian F. Walters

2012-01-01

Wildlife species-habitat matrices are used to relate lists of species with abundance of their habitats. The Forest Inventory and Analysis Program provides data on forest composition and structure, but these attributes may not correspond directly with definitions of wildlife habitats. We used FIA tree data and tree crown diameter models to estimate canopy cover, from...

Thinning northern hardwoods in New England by dominant-tree removal — early results

Treesearch

William Leak

2007-01-01

Commercial thinning is a widely accepted practice in northern hardwood stands of New England. Commercial thinning guidelines for eastern hardwoods generally recommend releasing selected crop trees or the removal of trees in less-than-dominant crown classes unless they are of poor health or quality. However, many northern hardwood stands in New England have a dominant...

Establishment of monitoring plots and evaluation of trees injured by ozone

Treesearch

Daniel Duriscoe; Kenneth Stolte; John Pronos

1996-01-01

By establishing long–term monitoring plots, it is possible to record environmental and biological conditions of the plot and individual trees, evaluate the condition of crowns of trees in the plot, and determine the extent of ozone injury to western conifers. This chapter recommends various methods for recording data and selecting plots, and provides information for...

First report of Armillaria root disease caused by Armillaria tabescens on Araucaria araucana in Veracruz, Mexico

Treesearch

M.-S. Kim; N. B. Klopfenstein; J. W. Hanna; P. Cannon; R. Medel; A. Lopez

2010-01-01

In September 2007, bark samples were collected from the root collar of a single Araucaria araucana tree that had recently died and was suspected of being killed by Armillaria root disease. Disease symptoms and signs included a thinning crown and fruiting bodies at the tree base over a several-year period before tree death.

Growth patterns of red pine on fine-textured soils.

Treesearch

David H. Alban; Donald H. Prettyman; Gary J. Brand

1987-01-01

Compares growth of 28- to 49-year-old red pine plantations on sandy and fine-textured soils. Red pine growing on these two contrasting soils did not differ in bole form, live crown ratio, or mortality, and tree growth predicted by models (STEMS and REDPINE) developed from trees growing on sandy soils worked equally well for trees growing on fine-textured soils.

Response of dwarf mistletoe-infested ponderosa pine to thinning: 2. Dwarf mistletoe propagation.

Treesearch

Lewis F. Roth; James W. Barrett

1985-01-01

Propagation of dwarf mistletoe in ponderosa pine saplings is little influenced by thinning overly dense stands to 250 trees per acre. Numerous plants that appear soon after thinning develop from formerly latent plants in the suppressed under-story. Subsequently, dwarf mistletoe propagates nearly as fast as tree crowns enlarge but the rate differs widely among trees....

Tree height estimation in redwood/Douglas-fir stands in Mendocino County

Treesearch

Helge Eng

2012-01-01

In this study, height-diameter equations were developed for managed stands of coastal redwood/Douglas-fir stands in Mendocino County. Equations were developed by species to predict tree height as a function of diameter as well as other factors that are known to potentially explain tree height, including site class and live crown ratio. Two equation forms were compared...

Effect of crown growing space and age on the growth of northern red oak

Treesearch

Gary W. Miller

1997-01-01

Cultural practices can be applied in even-age stands to reallocate site resources to selected crop trees. Precornrnercial thinning in sapling stands can increase diameter growth and improve species composition of trees in the main canopy. Commercial thinning in sawtimber stands also increases diameter growth of crop trees, improves residual stand quality, and removes...

Sampling strategies for efficient estimation of tree foliage biomass

Treesearch

Hailemariam Temesgen; Vicente Monleon; Aaron Weiskittel; Duncan Wilson

2011-01-01

Conifer crowns can be highly variable both within and between trees, particularly with respect to foliage biomass and leaf area. A variety of sampling schemes have been used to estimate biomass and leaf area at the individual tree and stand scales. Rarely has the effectiveness of these sampling schemes been compared across stands or even across species. In addition,...

[RS estimation of inventory parameters and carbon storage of moso bamboo forest based on synergistic use of object-based image analysis and decision tree].

PubMed

Du, Hua Qiang; Sun, Xiao Yan; Han, Ning; Mao, Fang Jie

2017-10-01

By synergistically using the object-based image analysis (OBIA) and the classification and regression tree (CART) methods, the distribution information, the indexes (including diameter at breast, tree height, and crown closure), and the aboveground carbon storage (AGC) of moso bamboo forest in Shanchuan Town, Anji County, Zhejiang Province were investigated. The results showed that the moso bamboo forest could be accurately delineated by integrating the multi-scale ima ge segmentation in OBIA technique and CART, which connected the image objects at various scales, with a pretty good producer's accuracy of 89.1%. The investigation of indexes estimated by regression tree model that was constructed based on the features extracted from the image objects reached normal or better accuracy, in which the crown closure model archived the best estimating accuracy of 67.9%. The estimating accuracy of diameter at breast and tree height was relatively low, which was consistent with conclusion that estimating diameter at breast and tree height using optical remote sensing could not achieve satisfactory results. Estimation of AGC reached relatively high accuracy, and accuracy of the region of high value achieved above 80%.

Linear mixed-effects models to describe individual tree crown width for China-fir in Fujian Province, southeast China.

PubMed

Hao, Xu; Yujun, Sun; Xinjie, Wang; Jin, Wang; Yao, Fu

2015-01-01

A multiple linear model was developed for individual tree crown width of Cunninghamia lanceolata (Lamb.) Hook in Fujian province, southeast China. Data were obtained from 55 sample plots of pure China-fir plantation stands. An Ordinary Linear Least Squares (OLS) regression was used to establish the crown width model. To adjust for correlations between observations from the same sample plots, we developed one level linear mixed-effects (LME) models based on the multiple linear model, which take into account the random effects of plots. The best random effects combinations for the LME models were determined by the Akaike's information criterion, the Bayesian information criterion and the -2logarithm likelihood. Heteroscedasticity was reduced by three residual variance functions: the power function, the exponential function and the constant plus power function. The spatial correlation was modeled by three correlation structures: the first-order autoregressive structure [AR(1)], a combination of first-order autoregressive and moving average structures [ARMA(1,1)], and the compound symmetry structure (CS). Then, the LME model was compared to the multiple linear model using the absolute mean residual (AMR), the root mean square error (RMSE), and the adjusted coefficient of determination (adj-R2). For individual tree crown width models, the one level LME model showed the best performance. An independent dataset was used to test the performance of the models and to demonstrate the advantage of calibrating LME models.

SPRUCE Tree Growth Assessments of Picea and Larix in S1-Bog Plots and SPRUCE Experimental Plots beginning in 2011

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

Hanson, P.J.,; Phillips, J.R.; Wullschelger, S.D.

This data set reports tree growth measurements of mature Picea mariana and Larix laricina located in the S1-Bog permanent plots and the SPRUCE experimental study plots, Annual data collections were initiated in February of 2011and have been continued on an annual basis during mid-winter observation periods at the end of February or early March. Data collections are anticipated to continue through February of 2025 and this data set will be appended annually. Initial observations in 2011 included measurements of circumference at 1.3 m (diameter at breast height assessments; DBH) above the nominal bog hollow surface, tree heights and crown diameters.more » Subsequent annual measurements have focused on the measures of circumference at DBH. Circumference measurements to the nearest 0.1 cm are converted to DBH in cm and basal area at DBH in (cm2). Tree height and crown diameter are measured to the nearest 0.1 m.« less

Influence of Preadjusted Bracket Shape and Positioning Reference on Angulation of Upper Central Incisor.

PubMed

Topolski, Francielle; de O Accorsi, Mauricio A; Trevisi, Hugo J; Cuoghi, Osmar A; Moresca, Ricardo

2016-10-01

To verify the influence of different bracket shapes and placement references according to Andrews and MBT systems on the expression of angulation in upper central incisors (UCI). Bracket positioning and mesiodistal dental movement simulations were performed and the angulations produced in the dental crown were evaluated, based on computed tomography scan images of 30 UCI and AutoCAD software analysis. Rectangular (Andrews) and rhomboid (MBT) brackets were placed according to the references recommended by Andrews and MBT systems - long axis of the clinical crown (LACC) and incisal edge (IE) respectively. Data showed that the use of LACC as reference for bracket positioning produced 5° and 4° UCI angulations in Andrews and MBT brackets respectively. The use of IE produced a 1.2° mean angulation in UCI for both brackets. When the LACC was used as reference for bracket positioning, the UCI crown angulation corresponded to the angulation built into the brackets, regardless of shape, while the use of IE resulted in natural crown angulation, regardless of bracket shape. This research contributes to guide the orthodontist in relation to the different treatment techniques based on the use of preadjusted brackets.

A framework for incorporating the effects of hydrodynamic stresses on forest photosynthesis and evaporation

NASA Astrophysics Data System (ADS)

Matheny, A. M.; Bohrer, G.; Thompsen, J.; Frasson, R.; Frasson, C. D.; Ivanov, V. Y.

2012-12-01

Hydraulic limitations are known to control transpiration in forest ecosystems when the soil is drying or when the vapor pressure deficit between the air and stomata (VPD) is very large, but they can also impact stomatal apertures under conditions of adequate soil moisture and lower evaporative demand. We use the NACP flux measurements and models dataset for multiple site/model intercomparisons to evaluate the degree to which currently un-resolved high-frequency (sub-daily) hydrodynamic stresses affect the error in model prediction of latent heat flux. We find that many site-model combinations are characterized by a typical pattern of overestimation of afternoon flux and a corresponding underestimation of pre-noon flux. We hypothesize that this pattern is a result of un-resolved afternoon stomata closure due to hydrodynamic stresses. In a forest plot at the University of Michigan Biological Station, we use measurements of leaf-level stomata conductance and water potential to demonstrate that trees of similar type - mid-late successional deciduous trees - have very different hydrodynamic strategies that lead to differences in their temporal patterns of stomata conductance. We found that red oak trees continue transpiring despite a large stem-water deficit while red maple trees regulate stomata to maintain a high water potential. Red oaks, which are ring porous, are also able to access more soil water, assumingly from deeper ground layers and have higher conductivity, compared with the maples, which are diffuse porous. These differences will lead to large differences in stomata conductance and water use based on the species composition of the forest. We also demonstrate that the size and shape of the tree stem-branch system may lead to differences in the extent of hydrodynamic stress, which may change the forest respiration patterns as the forest grows and ages. We propose a framework to resolve tree hydrodynamics in global and regional models. It is based on the Finite-Elements Tree-Crown Hydrodynamics model (FETCH) combined with a statistical functional-type/hydraulic-type/size representation of the trees in the forest. Lidar and multi-spectral images of the forest can be used to obtain numerical distributions of species and size of individual tree crowns needed to initialize such simulations. FETCH simulates water flow through the tree as a simplified system of porous media conduits. It explicitly resolves spatiotemporal hydraulic stresses throughout the tree's hydraulic system that cannot be easily represented using other stomatal-conductance models. It uses a physical representation of water flow in a 3-D tree-stem-branch system assuming the xylem is a porous media. Empirical equations relate water potential at the branch-tips to stomata conductance at leaves connected to these branches. FETCH calculates the hydrodynamic stress related closure of stomata, provided the atmospheric and biological variables from the global model, and could replace the current empirical formulation for stomata adjustment based on soil moisture.

[Three-dimensional data fusion method for tooth crown and root based on curvature continuity algorithm].

PubMed

Zhao, Y J; Liu, Y; Sun, Y C; Wang, Y

2017-08-18

To explore a three-dimensional (3D) data fusion and integration method of optical scanning tooth crowns and cone beam CT (CBCT) reconstructing tooth roots for their natural transition in the 3D profile. One mild dental crowding case was chosen from orthodontics clinics with full denture. The CBCT data were acquired to reconstruct the dental model with tooth roots by Mimics 17.0 medical imaging software, and the optical impression was taken to obtain the dentition model with high precision physiological contour of crowns by Smart Optics dental scanner. The two models were doing 3D registration based on their common part of the crowns' shape in Geomagic Studio 2012 reverse engineering software. The model coordinate system was established by defining the occlusal plane. crown-gingiva boundary was extracted from optical scanning model manually, then crown-root boundary was generated by offsetting and projecting crown-gingiva boundary to the root model. After trimming the crown and root models, the 3D fusion model with physiological contour crown and nature root was formed by curvature continuity filling algorithm finally. In the study, 10 patients with dentition mild crowded from the oral clinics were followed up with this method to obtain 3D crown and root fusion models, and 10 high qualification doctors were invited to do subjective evaluation of these fusion models. This study based on commercial software platform, preliminarily realized the 3D data fusion and integration method of optical scanning tooth crowns and CBCT tooth roots with a curvature continuous shape transition. The 10 patients' 3D crown and root fusion models were constructed successfully by the method, and the average score of the doctors' subjective evaluation for these 10 models was 8.6 points (0-10 points). which meant that all the fusion models could basically meet the need of the oral clinics, and also showed the method in our study was feasible and efficient in orthodontics study and clinics. The method of this study for 3D crown and root data fusion could obtain an integrate tooth or dental model more close to the nature shape. CBCT model calibration may probably improve the precision of the fusion model. The adaptation of this method for severe dentition crowding and micromaxillary deformity needs further research.

A morphometric analysis of maxillary molar crowns of Middle-Late Pleistocene hominins.

PubMed

Bailey, Shara E

2004-09-01

This study explores the significance of shape differences in the maxillary first molar crowns of Neandertals and anatomically modern humans. It uses morphometric analysis to quantify these differences and to investigate how the orientation of major cusps, relative cusp base areas and occlusal polygon area influence crown shape. The aims of this study were to 1) quantify these data to test whether the tooth shapes of Neandertals and anatomically modern humans differ significantly and 2) to explore if either of the shapes is derived relative to earlier fossil hominins. Data were collected from digital occlusal photographs using image-processing software. Cusp angles, relative cusp base areas and occlusal polygon areas were measured on Neandertals (n=15), contemporary modern humans (n=62), Upper Paleolithic humans (n=6), early anatomically modern humans (n=3) and Homo erectus (n=3). Univariate and multivariate statistical tests were used to evaluate the differences between contemporary modern humans and Neandertals, while the much sparser data sets from the other fossil samples were included primarily for comparison. Statistically significant differences reflecting overall crown shape and internal placement of the crown apices were found. Neandertals are distinguished from contemporary humans by possessing maxillary first molars that 1) are markedly skewed; 2) possess a narrower distal segment of the occlusal polygon compared to the mesial segment; 3) possess a significantly smaller metacone and a significantly larger hypocone; and 4) possess a significantly smaller relative occlusal polygon area reflecting internally placed cusps. Differences in relative cusp base areas of the hypocone and metacone may contribute to the shape differences observed in Neandertals. However, early anatomically modern humans possessing a pattern of relative cusp base areas similar to Neandertals lack their unusual shape. That the morphology observed in non-Neandertal fossil hominins is more anatomically modern human-like than Neandertal-like, suggests that this distinctive morphology may be derived in Neandertals.

Transmission components of solar radiation in pine stands in relation to climatic and stand variables

Treesearch

Robert A. Muller

1971-01-01

In a new approach, transmission was studied by relating to stand biomass the ratio of incoming solar radiation beneath tree crowns to that within the atmosphere. Several assumptions were used to estimate analytically the various ways in which solar radiation penetrates through crowns of three pine species in northern California. Sunflecks accounted for much of the...

Modeling tree-level fuel connectivity to evaluate the effectiveness of thinning treatments for reducing crown fire potential

Treesearch

Marco A. Contreras; Russell A. Parsons; Woodam Chung

2012-01-01

Land managers have been using fire behavior and simulation models to assist in several fire management tasks. These widely-used models use average attributes to make stand-level predictions without considering spatial variability of fuels within a stand. Consequently, as the existing models have limitations in adequately modeling crown fire initiation and propagation,...

Foliar nutrient variation in four species of upland oak

Treesearch

L. R. Auchmoody; K. P. Hammack

1975-01-01

Sampling of forest tree foliage for nutrient analyses is commonly restricted to specific and often dificult-to-reach locations such as the uppermost sun leaves growing on the south side of the crown. A study of 60-year-old red, white, chestnut, and scarlet oaks growing near Parsons, West Virginia, suggests that the easier-to-reach foliage from the lower crown is...

Potential fire behavior is reduced following forest restoration treatments

Treesearch

Peter Z. Fule; Charles McHugh; Thomas A. Heinlein; W. Wallace Covington

2001-01-01

Potential fire behavior was compared under dry, windy weather conditions in 12 ponderosa pine stands treated with alternative thinning prescriptions in the wildland/urban interface of Flagstaff, Arizona. Prior to thinning, stands averaged 474 trees/ acre, 158 ft2/acre basal area, crown bulk density 0.0045 lb/ft3, and crown base height 19.2 ft. Three thinning treatments...

Growth Reponse of Loblolly Pine to Intermediate Treatment of Fire, Herbicide, and Fertilizer: Preliminary Results

Treesearch

L.M. Marino; B.P. Oswald; K.W. Farrish; H.M. Williams; Daniel R. Unger

2002-01-01

Crown area is an important factor in determining stem development. This study examined the changes in stem diameter per unit area of crown due to treatment with fire, herbicide, fertilizer, and tree-thinning practice. The experimental sites were mid-rotation loblolly pine (Pinus taeda) plantations that were thinned one year before treatment. Site 1...

Biotic agents responsible for rapid crown decline and mortality of hickory in northeastern and north central USA

Treesearch

Jennifer Juzwik; Hi-Hyun Park; Mark T. Banik; Linda Haugen

2013-01-01

Severe decline and mortality of hickory (Carya spp.) occur periodically in the eastern United States. Recently, rapidly declining crowns followed by tree mortality were found to be the predominant symptoms based on a 2 year survey in six north central and northeastern states. Stems of actively declining bitternut hickory (Carya cordiformis...

Tree basal area as an index of thermal cover for elk.

Treesearch

J. Edward Dealy

1985-01-01

The relationship of basal area to crown closure was studied in five major forest types of the Blue Mountains of Oregon and Washington. The regressions developed give wildlife and forest managers a tool for estimating the amount of crown closure if data are not available from stand examinations. Information is used in determining quantity and quality of elk thermal...

Linking 3D spatial models of fuels and fire: Effects of spatial heterogeneity on fire behavior

Treesearch

Russell A. Parsons; William E. Mell; Peter McCauley

2011-01-01

Crownfire endangers fire fighters and can have severe ecological consequences. Prediction of fire behavior in tree crowns is essential to informed decisions in fire management. Current methods used in fire management do not address variability in crown fuels. New mechanistic physics-based fire models address convective heat transfer with computational fluid dynamics (...

Effects of thinning intensity and crown class on cherrybark oak epicormic branching five years after treatment

Treesearch

Luben D. Dimov; Erika Stelzer; Kristi Wharton; James S. Meadows; Jim L. Chambers; Kenny Ribbeck; E. Barry Moser

2006-01-01

Thinning in oak-dominated stands may have many desirable consequences, including increases in tree growth and mast production. One of the potential disadvantages, however, is the proliferation of epicormic branches, which leads to reduction in lumber quality and value. We assessed the effects of thinning intensity and initial crown class on cherrybark oak (...

Applications of Photogrammetry for Analysis of Forest Plantations. Preliminary study: Analysis of individual trees

NASA Astrophysics Data System (ADS)

Mora, R.; Barahona, A.; Aguilar, H.

2015-04-01

This paper presents a method for using high detail volumetric information, captured with a land based photogrammetric survey, to obtain information from individual trees. Applying LIDAR analysis techniques it is possible to measure diameter at breast height, height at first branch (commercial height), basal area and volume of an individual tree. Given this information it is possible to calculate how much of that tree can be exploited as wood. The main objective is to develop a methodology for successfully surveying one individual tree, capturing every side of the stem a using high resolution digital camera and reference marks with GPS coordinates. The process is executed for several individuals of two species present in the metropolitan area in San Jose, Costa Rica, Delonix regia (Bojer) Raf. and Tabebuia rosea (Bertol.) DC., each one with different height, stem shape and crown area. Using a photogrammetry suite all the pictures are aligned, geo-referenced and a dense point cloud is generated with enough detail to perform the required measurements, as well as a solid tridimensional model for volume measurement. This research will open the way to develop a capture methodology with an airborne camera using close range UAVs. An airborne platform will make possible to capture every individual in a forest plantation, furthermore if the analysis techniques applied in this research are automated it will be possible to calculate with high precision the exploit potential of a forest plantation and improve its management.

The ghosts of trees past: savanna trees create enduring legacies in plant species composition.

PubMed

Stahlheber, Karen A; Crispin, Kimberly L; Anton, Cassidy; D'Antonio, Carla M

2015-09-01

Isolated trees in savannas worldwide are known to modify their local environment and interact directly with neighboring plants. Less is known about how related tree species differ in their impacts on surrounding communities, how the effects of trees vary between years, and how composition might change following loss of the tree. To address these knowledge gaps, we explored the following questions: How do savanna trees influence the surrounding composition of herbaceous plants? Is the influence of trees consistent across different species and years? How does this change following the death of the tree? We surveyed herbaceous species composition and environmental attributes surrounding living and dead evergreen and deciduous Quercus trees in California (USA) savannas across several years that differed in their total precipitation. Oak trees of all species created distinct, homogenous understory communities dominated by exotic grasses across several sites. The composition of the low-diversity understory communities showed less interannual variation than open grassland, despite a two-fold difference in precipitation between the driest and wettest year. Vegetation composition was correlated with variation in soil properties, which were strongly affected by trees. Oaks also influenced the communities beyond the edge of the crown, but this depended on site and oak species. Low-diversity understory communities persisted up to 43 years following the death of the tree. A gradual decline in the effect of trees on the physical, environment following death did not result in vegetation becoming more similar to open grassland over time. The presence of long-lasting legacies of past tree crowns highlights the difficulty of assigning control of the current distribution of herbaceous species in grassland to their contemporary environment.

Factors controlling plasticity of leaf morphology in Robinia pseudoacacia L. II: the impact of water stress on leaf morphology of seedlings grown in a controlled environment chamber

Treesearch

M.T. Tyree

2012-01-01

Context. The cause of morphological plasticity of leaves within the crowns of tall trees still debated. Whether it is driven by irradiance or hydraulic constraints is inconclusive. In a previous study, we hypothesized that water stress caused between-site and within-tree morphological variability in mature Robinia trees.

Dwarf mistletoe does not increase trunk taper in released red firs in California

Treesearch

Robert F. Scharpf

1977-01-01

Dwarf mistletoe had no noticeable effect on trunk taper of young, dominant and codominant red firs 4 to 22 inches (10.2 to 55.9 cm) d.b.h. Also, taper was not influenced by live crown ratio of infected and uninfected trees. Trees less than 7 inches d.b.h. had significantly more taper than larger trees, irrespective of dwarf mistletoe.

Shade factors for 149 taxa of in-leaf urban trees in the USA

Treesearch

E. Gregory McPherson; Qingfu Xiao; Natalie S. van Doorn; Nels Johnson; Shannon Albers; Paula J. Peper

2018-01-01

Shade factors, defined as the percentage of sky covered by foliage and branches within the perimeter of individual tree crowns, have been used to model the effects of trees on air pollutant uptake, building energy use and rainfall interception. For the past 30 years the primary source of shade factors was a database containing values from 47 species. In most...

Estimating Pinus palustris tree diameter and stem volume from tree height, crown area and stand-level parameters

Treesearch

C.A. Gonzalez-Benecke; Salvador A. Gezan; Lisa J. Samuelson; Wendell P. Cropper; Daniel J. Leduc; Timothy A. Martin

2014-01-01

Accurate and efficient estimation of forest growth and live biomass is a critical element in assessing potential responses to forest management and environmental change. The objective of this study was to develop models to predict longleaf pine tree diameter at breast height (dbh) and merchantable stem volume (V) using data obtained from field measurements. We used...

Foliage Sampling Guides for Loblolly Pine

Treesearch

Carol G. Wells

1969-01-01

Loblolly pine (Pinus taeda L.) trees were sampled to determine the effect of growth flush, crown position of pole trees, and winter temperature extremes upon the nutrient content of needles. Winter temperatures did not have an important influence upon elemental content. Because concentrations of several elements differed for Ihe first, second, and...

Effect of pruning on growth of ponderosa pine.

Treesearch

Edwin L. Mowat

1947-01-01

A study of the influence of pruning various proportions of the crowns of young ponderosa pine trees upon growth, vigor, and mortality was started on the Pringle Falls Experimental Forest in 1941. After 5 years of tree growth, the study throws some light on how severely young pines should be pruned.

A novel approach for individual tree crown delineation using lidar data

NASA Astrophysics Data System (ADS)

Liu, Tao

Individual tree crown delineation (ITCD) is an important technique to support precision forestry. ITCD is particularly difficult for deciduous forests where the existence of multiple branches can lead to false tree top detection. This thesis focused on developing a new ITCD model, which consists of two components: (1) boundary refinement using a novel algorithm called Fishing Net Dragging (FiND), and (2) segment merging using boundary classification. The proposed ITCD model was tested in both deciduous and mixed forests, attaining an overall accuracy of 74% and 78%, respectively. This compared favorably to an ITCD method commonly cited in the literature, which attained 41% and 51% on the same plots. To facilitate comparison of research in the ITCD community, this thesis also developed a new accuracy assessment scheme for ITCD. This new accuracy assessment is easy to interpret and convenient to implement while comprehensively evaluating ITCD accuracy.

Potassium nutrition and water availability affect phloem transport of photosynthetic carbon in eucalypt trees

NASA Astrophysics Data System (ADS)

Epron, Daniel; Cabral, Osvaldo; Laclau, Jean-Paul; Dannoura, Masako; Packer, Ana Paula; Plain, Caroline; Battie-Laclau, Patricia; Moreira, Marcelo; Trivelin, Paulo; Bouillet, Jean-Pierre; Gérant, Dominique; Nouvellon, Yann

2015-04-01

Potassium fertilisation strongly affects growth and carbon partitioning of eucalypt on tropical soil that are strongly weathered. In addition, potassium fertilization could be of great interest in mitigating the adverse consequences of drought in planted forests, as foliar K concentrations influence osmotic adjustment, stomatal regulation and phloem loading. Phloem is the main pathway for transferring photosynthate from source leaves to sink organs, thus controlling growth partitioning among the different tree compartments. But little is known about the effect of potassium nutrition on phloem transport of photosynthetic carbon and on the interaction between K nutrition and water availability. In situ 13C pulse labelling was conducted on tropical eucalypt trees (Eucalyptus grandis L.) grown in a trial plantation with plots in which 37% of throughfall were excluded (about 500 mm/yr) using home-made transparent gutters (-W) or not (+W) and plots that received 0.45 mol K m-2 applied as KCl three months after planting (+K) or not (-K). Three trees were labelled in each of the four treatments (+K+W, +K-W, -K+W and -K-W). Trees were labelled for one hour by injecting pure 13CO2 in a 27 m3 whole crown chamber. We estimated the velocity of carbon transfer in the trunk by comparing time lags between the uptake of 13CO2 and its recovery in trunk CO2 efflux recorded by off axis integrated cavity output spectroscopy (Los Gatos Research) in two chambers per tree, one just under the crown and one at the base of the trunk. We analyzed the dynamics of the label recovered in the foliage and in the phloem sap by analysing carbon isotope composition of bulk leaf organic matter and phloem extracts using an isotope ratio mass spectrometer. The velocity of carbon transfer in the trunk and the initial rate 13C disappearance from the foliage were much higher in +K trees than in -K trees with no significant effect of rainfall. The volumetric flow of phloem, roughly estimated by multiplying the velocity of C transfer with the bark cross-section area of tree at 1.30m high, was also higher in +K trees than in -K trees and well-correlated with crown photosynthesis and with the xylem sapflow density.

Multispectral sensing of citrus young tree decline

NASA Technical Reports Server (NTRS)

Edwards, G. J.; Ducharme, E. P.; Schehl, T.

1975-01-01

Computer processing of MSS data to identify and map citrus trees affected by young tree decline is analyzed. The data were obtained at 1500-feet altitude in six discrete spectral bands covering regions from 0.53 to 1.3 millimicrons as well as from instrumental ground truths of tree crowns. Measurable spectral reflectance intensity differences are observed in the leaves of healthy and diseased trees, especially at wavelengths of 500 to 600 nm and 700 to 800 nm. The overall accuracy of the method is found to be 89%.

Geometrical modeling of complete dental shapes by using panoramic X-ray, digital mouth data and anatomical templates.

PubMed

Barone, Sandro; Paoli, Alessandro; Razionale, Armando Viviano

2015-07-01

In the field of orthodontic planning, the creation of a complete digital dental model to simulate and predict treatments is of utmost importance. Nowadays, orthodontists use panoramic radiographs (PAN) and dental crown representations obtained by optical scanning. However, these data do not contain any 3D information regarding tooth root geometries. A reliable orthodontic treatment should instead take into account entire geometrical models of dental shapes in order to better predict tooth movements. This paper presents a methodology to create complete 3D patient dental anatomies by combining digital mouth models and panoramic radiographs. The modeling process is based on using crown surfaces, reconstructed by optical scanning, and root geometries, obtained by adapting anatomical CAD templates over patient specific information extracted from radiographic data. The radiographic process is virtually replicated on crown digital geometries through the Discrete Radon Transform (DRT). The resulting virtual PAN image is used to integrate the actual radiographic data and the digital mouth model. This procedure provides the root references on the 3D digital crown models, which guide a shape adjustment of the dental CAD templates. The entire geometrical models are finally created by merging dental crowns, captured by optical scanning, and root geometries, obtained from the CAD templates. Copyright © 2015 Elsevier Ltd. All rights reserved.

Red Oak Research and Demonstration Area in Phelps Township, North Bay, Ontario-2004 to 2005

Treesearch

Dave Deugo; Andrée Morneault; Dianne Othmer; Megan Smith; Al Stinson; Murray Woods; Ian Kovacs; Ian Aho; Bill Parker; Rob Baker; Marinus Verwey; Guylaine Thauvette; Don Willis; Jeff Dech

2006-01-01

In July 2004, a large stand of red oak (Quercus rubra) was harvested in Phelps Township, North Bay District, North Bay, Ontario using the uniform shelterwood system. Most of the stand was harvested to retain 40 percent crown closure, while a very small portion was harvested to retain 70 percent crown closure. During tree marking, an active Northern...

Has Virginia pine declined? The use of forest health monitoring and other information in the determination

Treesearch

William G. Burkman; William A. Bechtold

2000-01-01

This paper examines the current status of Virginia pine, focusing on Forest Health Monitoring (FHM) results and using Forest Inventory and Analysis (FIA) information to determine if Virginia pine is showing a decline. An examination of crown condition data from live trees in the FHM program from 1991 through 1997 showed that Virginia pine had significantly poorer crown...

Do mountain pine beetle outbreaks change the probability of active crown fire in lodgepole pine forests?

Treesearch

W. Matt Jolly; Russell Parsons; J. Morgan Varner; Bret W. Butler; Kevin C. Ryan; Corey L. Gucker

2012-01-01

An expansive mountain pine beetle (MPB) epidemic is currently impacting North American forests (Raffa et al. 2008). As beetle-attacked trees die, lose their needles, and eventually fall to the ground, there are substantial changes in stand structure. These fuel changes likely affect both surface and crown fire behavior, but there is not yet a consensus among experts...

Development history and bibliography of the US Forest Service crown-condition indicator for forest health monitoring

Treesearch

KaDonna Randolph

2013-01-01

Comprehensive assessment of individual-tree crown condition by the US Department of Agriculture, Forest Service, Forest Inventory and Analysis (FIA) Program has its origins in the concerns about widespread forest decline in Europe and North America that developed in the late 1970s and early 1980s. Programs such as the US National Acid Precipitation Assessment Program,...

Growth ring response in shortleaf pine following glaze icing conditions in western Arkansas and eastern Oklahoma

Treesearch

Douglas J. Stevenson; Thomas B. Lynch; James M. Guldin

2013-01-01

Width reduction in growth rings in shortleaf pine (Pinus echinata Mill.) following glaze ice conditions produces a characteristic pattern dependent on live-crown ratio and extent of crown loss. Ring widths of 133 trees for 3 years preceding and 7 years following the December 2000 ice storm (Bragg and others 2002) in western Arkansas and eastern...

Ten-year effects from row thinnings in loblolly pine plantations of eastern Maryland

Treesearch

Silas Little; John J. Mohr; Paul V. Mook

1967-01-01

Four degrees of row thinning were tested in 17-year-old loblolly pine plantations of eastern Maryland. In the following 10 years diameter and basal-area growth of tagged trees increased in relation to intensity of thinning. The heavier thinnings also had the most effect in increasing live-crown lengths and ratios and in favoring crown-class position. Volume growth was...

Stress distribution difference between Lava Ultimate full crowns and IPS e.max CAD full crowns on a natural tooth and on tooth-shaped implant abutments.

PubMed

Krejci, Ivo; Daher, René

2017-04-01

The goal of this short communication is to present finite element analysis comparison of the stress distribution between CAD/CAM full crowns made of Lava Ultimate and of IPS e.max CAD, adhesively luted to natural teeth and to implant abutments with the shape of natural teeth. Six 3D models were prepared using a 3D content-creating software, based on a micro-CT scan of a human mandibular molar. The geometry of the full crown and of the abutment was the same for all models representing Lava Ultimate full crowns (L) and IPS e.max CAD full crowns (E) on three different abutments: prepared natural tooth (n), titanium abutment (t) and zirconia abutment (z). A static load of 400 N was applied on the vestibular and lingual cusps, and fixtures were applied to the base of the models. After running the static linear analysis, the post-processing data we analyzed. The stress values at the interface between the crown and the abutment of the Lt and Lz groups were significantly higher than the stress values at the same interface of all the other models. The high stress concentration in the adhesive at the interface between the crown and the abutment of the Lava Ultimate group on implants might be one of the factors contributing to the reported debondings of crowns.

[Vertical variability of Pinus sylvestris var. mongolica tree ring delta13C and its relationship with tree ring width in northern Daxing' an Mountains of Northeast China].

PubMed

Shang, Zhi-Yuan; Wang, Jian; Zhang, Wen; Li, Yan-Yan; Cui, Ming-Xing; Chen, Zhen-Ju; Zhao, Xing-Yun

2013-01-01

A measurement was made on the vertical direction tree ring stable carbon isotope ratio (delta13C) and tree ring width of Pinus sylvestris var. mongolica in northern Daxing' an Mountains of Northeast China, with the relationship between the vertical direction variations of the tree ring delta13C and tree ring width analyzed. In the whole ring of xylem, earlywood (EW) and bark endodermis, the delta13C all exhibited an increasing trend from the top to the base at first, with the maximum at the bottom of tree crown, and then, decreased rapidly to the minimum downward. The EW and late-wood (LW) had an increasing ratio of average tree ring width from the base to the top. The average annual sequence of the delta13C in vertical direction had an obvious reverse correspondence with the average annual sequence of tree ring width, and had a trend comparatively in line with the average annual sequence of the tree ring width ratio of EW to LW above tree crown. The variance analysis showed that there existed significant differences in the sequences of tree ring delta13C and ring width in vertical direction, and the magnitude of vertical delta13C variability was basically the same as that of the inter-annual delta13C variability. The year-to-year variation trend of the vertical delta13C sequence was approximately identical. For each sample, the delta13C sequence at the same heights was negatively correlated with the ring width sequence, but the statistical significance differed with tree height.

Responses of riparian cottonwoods to alluvial water table declines

USGS Publications Warehouse

Scott, M.L.; Shafroth, P.B.; Auble, G.T.

1999-01-01

Human demands for surface and shallow alluvial groundwater have contributed to the loss, fragmentation, and simplification of riparian ecosystems. Populus species typically dominate riparian ecosystems throughout arid and semiarid regions of North American and efforts to minimize loss of riparian Populus requires an integrated understanding of the role of surface and groundwater dynamics in the establishment of new, and maintenance of existing, stands. In a controlled, whole-stand field experiment, we quantified responses of Populus morphology, growth, and mortality to water stress resulting from sustained water table decline following in-channel sand mining along an ephemeral sandbed stream in eastern Colorado, USA. We measured live crown volume, radial stem growth, annual branch increment, and mortality of 689 live Populus deltoides subsp. monilifera stems over four years in conjunction with localized water table declines. Measurements began one year prior to mining and included trees in both affected and unaffected areas. Populus demonstrated a threshold response to water table declines in medium alluvial sands; sustained declines ???1 m produced leaf desiccation and branch dieback within three weeks and significant declines in live crown volume, stem growth, and 88% mortality over a three-year period. Declines in live Crown volume proved to be a significant leading indicator of mortality in the following year. A logistic regression of tree survival probability against the prior year's live crown volume was significant (-2 log likelihood = 270, ??2 with 1 df = 232, P < 0.0001) and trees with absolute declines in live crown volume of ???30 during one year had survival probabilities <0.5 in the following year. In contrast, more gradual water table declines of ~0.5 m had no measurable effect on mortality, stem growth, or live crown volume and produced significant declines only in annual branch growth increments. Developing quantitative information on the timing and extent of morphological responses and mortality of Populus to the rate, depth, and duration of water table declines can assist in the design of management prescriptions to minimize impacts of alluvial groundwater depletion on existing riparian Populus forests.

Crown traits of coniferous trees and their relation to shade tolerance can differ with leaf type: a biophysical demonstration using computed tomography scanning data

PubMed Central

Dutilleul, Pierre; Han, Liwen; Valladares, Fernando; Messier, Christian

2015-01-01

Plant light interception and shade tolerance are intrinsically related in that they involve structural, morphological and physiological adaptations to manage light capture for photosynthetic utilization, in order to sustain survival, development and reproduction. At the scale of small-size trees, crown traits related to structural geometry of branching pattern and space occupancy through phyllotaxis can be accurately evaluated in 3D, using computed tomography (CT) scanning data. We demonstrate this by scrutinizing the crowns of 15 potted miniature conifers of different species or varieties, classified in two groups based on leaf type (10 needlelike, 5 scalelike); we also test whether mean values of crown traits measured from CT scanning data and correlations with a shade tolerance index (STI) differ between groups. Seven crown traits, including fractal dimensions (FD1: smaller scales, FD2: larger scales) and leaf areas, were evaluated for all 15 miniature conifers; an average silhouette-to-total-area ratio was also calculated for each of the 10 needlelike-leaf conifers. Between-group differences in mean values are significant (P < 0.05) for STI, FD1, FD2, and the average leaf area displayed (ĀD). Between-group differences in sign and strength of correlations are observed. For example, the correlation between STI and FD1 is negative and significant (P < 0.10) for the needlelike-leaf group, but is positive and significant (P < 0.05) for the miniature conifers with scalelike leaves, which had lower STI and higher FD1 on average in our study; the positive correlation between STI and ĀD is significant (P < 0.05) for the scalelike-leaf group, and very moderate for the needlelike-leaf one. A contrasting physical attachment of the leaves to branches may explain part of the between-group differences. Our findings open new avenues for the understanding of fundamental plant growth processes; the information gained could be included in a multi-scale approach to tree crown modeling. PMID:25852721

The efficacy of salvage logging in reducing subsequent fire severity in conifer-dominated forests of Minnesota, U.S.A.

PubMed

Fraver, Shawn; Jain, Theresa; Bradford, John B; D'Amato, Anthony W; Kastendick, Doug; Palik, Brian; Shinneman, Doug; Stanovick, John

2011-09-01

Although primarily used to mitigate economic losses following disturbance, salvage logging has also been justified on the basis of reducing fire risk and fire severity; however, its ability to achieve these secondary objectives remains unclear. The patchiness resulting from a sequence of recent disturbances-blowdown, salvage logging, and wildfire-provided an excellent opportunity to assess the impacts of blowdown and salvage logging on wildfire severity. We used two fire-severity assessments (tree-crown and forest-floor characteristics) to compare post-wildfire conditions among three treatment combinations (Blowdown-Salvage-Fire, Blowdown-Fire, and Fire only). Our results suggest that salvage logging reduced the intensity (heat released) of the subsequent fire. However, its effect on severity (impact to the system) differed between the tree crowns and forest floor: tree-crown indices suggest that salvage logging decreased fire severity (albeit with modest statistical support), while forest-floor indices suggest that salvage logging increased fire severity. We attribute the latter finding to the greater exposure of mineral soil caused by logging operations; once exposed, soils are more likely to register the damaging effects of fire, even if fire intensity is not extreme. These results highlight the important distinction between fire intensity and severity when formulating post-disturbance management prescriptions.

Fog interception by Sequoia sempervirens (D. Don) crowns decouples physiology from soil water deficit.

PubMed

Simonin, Kevin A; Santiago, Louis S; Dawson, Todd E

2009-07-01

Although crown wetting events can increase plant water status, leaf wetting is thought to negatively affect plant carbon balance by depressing photosynthesis and growth. We investigated the influence of crown fog interception on the water and carbon relations of juvenile and mature Sequoia sempervirens trees. Field observations of mature trees indicated that fog interception increased leaf water potential above that of leaves sheltered from fog. Furthermore, observed increases in leaf water potential exceeded the maximum water potential predicted if soil water was the only available water source. Because field observations were limited to two mature trees, we conducted a greenhouse experiment to investigate how fog interception influences plant water status and photosynthesis. Pre-dawn and midday branchlet water potential, leaf gas exchange and chlorophyll fluorescence were measured on S. sempervirens saplings exposed to increasing soil water deficit, with and without overnight canopy fog interception. Sapling fog interception increased leaf water potential and photosynthesis above the control and soil water deficit treatments despite similar dark-acclimated leaf chlorophyll fluorescence. The field observations and greenhouse experiment show that fog interception represents an overlooked flux into the soil-plant-atmosphere continuum that temporarily, but significantly, decouples leaf-level water and carbon relations from soil water availability.

The efficacy of salvage logging in reducing subsequent fire severity in conifer-dominated forests of Minnesota, USA

USGS Publications Warehouse

Fraver, S.; Jain, T.; Bradford, J.B.; D'Amato, A.W.; Kastendick, D.; Palik, B.; Shinneman, D.; Stanovick, J.

2011-01-01

Although primarily used to mitigate economic losses following disturbance, salvage logging has also been justified on the basis of reducing fire risk and fire severity; however, its ability to achieve these secondary objectives remains unclear. The patchiness resulting from a sequence of recent disturbances-blowdown, salvage logging, and ildfire- provided an excellent opportunity to assess the impacts of blowdown and salvage logging on wildfire severity. We used two fire-severity assessments (tree-crown and forest-floor characteristics) to compare post-wildfire conditions among three treatment combinations (Blowdown-Salvage-Fire, Blowdown-Fire, and Fire only). Our results suggest that salvage logging reduced the intensity (heat released) of the subsequent fire. However, its effect on severity (impact to the system) differed between the tree crowns and forest floor: tree-crown indices suggest that salvage logging decreased fire severity (albeit with modest statistical support), while forest-floor indices suggest that salvage logging increased fire severity. We attribute the latter finding to the greater exposure of mineral soil caused by logging operations; once exposed, soils are more likely to register the damaging effects of fire, even if fire intensity is not extreme. These results highlight the important distinction between fire intensity and severity when formulating post-disturbance management prescriptions. ?? 2011 by the Ecological Society of America.

Bridging process-based and empirical approaches to modeling tree growth

Treesearch

Harry T. Valentine; Annikki Makela; Annikki Makela

2005-01-01

The gulf between process-based and empirical approaches to modeling tree growth may be bridged, in part, by the use of a common model. To this end, we have formulated a process-based model of tree growth that can be fitted and applied in an empirical mode. The growth model is grounded in pipe model theory and an optimal control model of crown development. Together, the...

Tree shaking machine aids cone collection in a Douglas-fir seed orchard.

Treesearch

Donald L. Copes; William K. Randall

1983-01-01

A boom-type tree shaker was used in a Douglas-fir seed orchard to remove cones from 7- to 9-meter tall grafted Douglas-fir trees. An average of 55 percent of the cones were removed by shaking, while damage inflicted to the upper crown was confined primarily to branch and leader breakage in the top three internodes. Damage to the lower bole, where the shaker head...

Parachuting behavior and predation by ants in the nettle caterpillar, Scopelodes contracta.

PubMed

Yamazaki, Kazuo

2010-01-01

This paper documents the bizarre descending behavior from the tree crown to the ground of the larvae of the moth, Scopelodes contracta Walker (Lepidoptera: Limacodidae) and the interaction of the larva with predatory ants. S. contracta larvae infest leaves of many tree species in urban areas and orchards in Japan. Mature larvae and leaves without basal leaf parts were found under trees of four species infested with S. contracta larvae in Osaka, Japan. Individual larvae riding on leaves were observed falling from tree crowns to the ground. Many S. contracta cocoons were found in the soil below the trees two weeks after the observed parachuting. These observations indicate that S. contracta larvae parachuted to the ground where they spin their cocoons in the soil. When a larva that had just parachuted down was returned to an arboreal twig, the larva repeated the parachuting behavior. This parachuting behavior appears to be adaptive, because larvae can descend to the ground safely and with low energy cost. Worker ants of Tetramorium tsushimae Emery (Hymenoptera: Formicidae) and Pristomyrmex punctatus Mayr (Hymenoptera: Formicidae) occasionally attacked larvae on the ground before they had a chance to burrow in the soil.

Extracting Features of Acacia Plantation and Natural Forest in the Mountainous Region of Sarawak, Malaysia by ALOS/AVNIR2 Image

NASA Astrophysics Data System (ADS)

Fadaei, H.; Ishii, R.; Suzuki, R.; Kendawang, J.

2013-12-01

The remote sensing technique has provided useful information to detect spatio-temporal changes in the land cover of tropical forests. Land cover characteristics derived from satellite image can be applied to the estimation of ecosystem services and biodiversity over an extensive area, and such land cover information would provide valuable information to global and local people to understand the significance of the tropical ecosystem. This study was conducted in the Acacia plantations and natural forest situated in the mountainous region which has different ecological characteristic from that in flat and low land area in Sarawak, Malaysia. The main objective of this study is to compare extract the characteristic of them by analyzing the ALOS/AVNIR2 images and ground truthing obtained by the forest survey. We implemented a ground-based forest survey at Aacia plantations and natural forest in the mountainous region in Sarawak, Malaysia in June, 2013 and acquired the forest structure data (tree height, diameter at breast height (DBH), crown diameter, tree spacing) and spectral reflectance data at the three sample plots of Acacia plantation that has 10 x 10m area. As for the spectral reflectance data, we measured the spectral reflectance of the end members of forest such as leaves, stems, road surface, and forest floor by the spectro-radiometer. Such forest structure and spectral data were incorporated into the image analysis by support vector machine (SVM) and object-base/texture analysis. Consequently, land covers on the AVNIR2 image were classified into three forest types (natural forest, oil palm plantation and acacia mangium plantation), then the characteristic of each category was examined. We additionally used the tree age data of acacia plantation for the classification. A unique feature was found in vegetation spectral reflectance of Acacia plantations. The curve of the spectral reflectance shows two peaks around 0.3μm and 0.6 - 0.8μm that can be assumed to be corresponded to the reflectance from the bare land part (soil) and forest crown in the Acacia forest, respectively. In accordance with this spectral characteristic, we can estimate the proportional areas of the bare land and crown cover of the tree in the acacia plantation forest that will provide essential information for evaluating the forest ecosystem. We will define Bare land and Tree Crown Ratio Index (BTRI) that represent ratio of the areas of tree crown to areas of their access roads. Such information will delineate the characteristics of Acacia plantation and natural forest in mountainous region, and enable us to compare them with the plantation and forest in flat and low land.

Stable oxygen isotope analysis reveal vegetation influence on soil water movement and ecosystem water fluxes in a semi-arid oak woodland

NASA Astrophysics Data System (ADS)

Piayda, Arndt; Dubbert, Maren; Werner, Christiane; Cuntz, Matthias

2015-04-01

Mechanistically disentangling the role and function of vegetation within the hydrological cycle is one of the key questions in the interdisciplinary field of ecohydrology. The presence of vegetation can have various impacts on soil water relations: transpiration of active vegetation causes great water losses, rainfall is intercepted, soil evaporation can be reduced and infiltration, hydraulic redistribution and translatory flow might be altered. In drylands, covering around 40% of the global land surface, the carbon cycle is closely coupled to water availability due to (seasonal) droughts. Specifically savannah type ecosystems, which cover large areas worldwide, are, due to their bi-layered structure, very suitable to study the effects of distinct vegetation types on the ecosystem water cycle. Oxygen isotope signatures (δ18O) have been used to partition ecosystem evapotranspiration (ET ) because of the distinct isotopic compositions of water transpired by leaves relative to soil evaporated vapor. Recent developments in laser spectroscopy enable measurements of δ18O in the vapor phase with high temporal resolution in the field and bear a novel opportunity to trace water movement within the ecosystem. In the present study, the effects of distinct vegetation layers (i.e. trees and herbaceous vegetation) on soil water infiltration and redistribution as well as ecosystem water fluxes in a Mediterranean cork-oak woodland are disentangled. An irrigation experiment was carried out using δ18O labeled water to quantify the distinct effects of trees and herbaceous vegetation on 1) infiltration and redistribution of water in the soil profile and 2) to disentangle the effects of tree cover on the contribution of unproductive soil evaporation and understory transpiration to total ET . First results proof that stable δ18O isotopes measured onsite with laser spectroscopy is a valuable tool to trace water movement in the soil showing a much higher sensitivity than common TDR-type probes. It was possible to track soil water redistribution even beyond zero net water flux measured with TDR probes. Under shaded conditions beneath tree crowns, infiltration of precipitation reaches much deeper depths due to the limited radiation energy input and thus, reduced evaporative losses, compared to open areas between crowns. As a consequence, the isotopic enrichment back to initial conditions (as observed before the artificial precipitation event) was strongly delayed. Despite the higher water availability beneath tree crowns, transpiration of understory plants and soil evaporation rates were reduced compared to the open area due to the lack of energy. However, transpiration could be maintained much longer and at higher rates after the precipitation event then soil evaporation. These first results support previous findings at this site where a clear difference in understory plant community structure was observed. Beneath tree crowns, favorable water conditions enables a higher occurrence of grasses and nitrogen fixing forbs, whereas in between tree crowns drought adapted native species became dominant.

A Metric on Phylogenetic Tree Shapes

PubMed Central

Plazzotta, G.

2018-01-01

Abstract The shapes of evolutionary trees are influenced by the nature of the evolutionary process but comparisons of trees from different processes are hindered by the challenge of completely describing tree shape. We present a full characterization of the shapes of rooted branching trees in a form that lends itself to natural tree comparisons. We use this characterization to define a metric, in the sense of a true distance function, on tree shapes. The metric distinguishes trees from random models known to produce different tree shapes. It separates trees derived from tropical versus USA influenza A sequences, which reflect the differing epidemiology of tropical and seasonal flu. We describe several metrics based on the same core characterization, and illustrate how to extend the metric to incorporate trees’ branch lengths or other features such as overall imbalance. Our approach allows us to construct addition and multiplication on trees, and to create a convex metric on tree shapes which formally allows computation of average tree shapes. PMID:28472435

D Modeling of Components of a Garden by Using Point Cloud Data

NASA Astrophysics Data System (ADS)

Kumazakia, R.; Kunii, Y.

2016-06-01

Laser measurement is currently applied to several tasks such as plumbing management, road investigation through mobile mapping systems, and elevation model utilization through airborne LiDAR. Effective laser measurement methods have been well-documented in civil engineering, but few attempts have been made to establish equally effective methods in landscape engineering. By using point cloud data acquired through laser measurement, the aesthetic landscaping of Japanese gardens can be enhanced. This study focuses on simple landscape simulations for pruning and rearranging trees as well as rearranging rocks, lanterns, and other garden features by using point cloud data. However, such simulations lack concreteness. Therefore, this study considers the construction of a library of garden features extracted from point cloud data. The library would serve as a resource for creating new gardens and simulating gardens prior to conducting repairs. Extracted garden features are imported as 3ds Max objects, and realistic 3D models are generated by using a material editor system. As further work toward the publication of a 3D model library, file formats for tree crowns and trunks should be adjusted. Moreover, reducing the size of created models is necessary. Models created using point cloud data are informative because simply shaped garden features such as trees are often seen in the 3D industry.

Nervous systems and scenarios for the invertebrate-to-vertebrate transition.

PubMed

Holland, Nicholas D

2016-01-05

Older evolutionary scenarios for the origin of vertebrates often gave nervous systems top billing in accordance with the notion that a big-brained Homo sapiens crowned a tree of life shaped mainly by progressive evolution. Now, however, tree thinking positions all extant organisms equidistant from the tree's root, and molecular phylogenies indicate that regressive evolution is more common than previously suspected. Even so, contemporary theories of vertebrate origin still focus on the nervous system because of its functional importance, its richness in characters for comparative biology, and its central position in the two currently prominent scenarios for the invertebrate-to-vertebrate transition, which grew out of the markedly neurocentric annelid and enteropneust theories of the nineteenth century. Both these scenarios compare phyla with diverse overall body plans. This diversity, exacerbated by the scarcity of relevant fossil data, makes it challenging to establish plausible homologies between component parts (e.g. nervous system regions). In addition, our current understanding of the relation between genotype and phenotype is too preliminary to permit us to convert gene network data into structural features in any simple way. These issues are discussed here with special reference to the evolution of nervous systems during proposed transitions from invertebrates to vertebrates. © 2015 The Author(s).

Distribution of leaf characteristics in relation to orientation within the canopy of woody species

NASA Astrophysics Data System (ADS)

Escudero, Alfonso; Fernández, José; Cordero, Angel; Mediavilla, Sonia

2013-04-01

Over the last few decades considerable effort has been devoted to research of leaf adaptations to environmental conditions. Many studies have reported strong differences in leaf mass per unit area (LMA) within a single tree depending on the photosynthetic photon flux density (PPFD) incident on different locations in the crown. There are fewer studies, however, of the effects of differences in the timing of light incidence during the day on different crown orientations. Leaves from isolated trees of Quercus suber and Quercus ilex in a cold Mediterranean climate were sampled to analyze differences in LMA and other leaf traits among different crown orientations. Gas-exchange rates, leaf water potentials, leaf temperatures and PPFD incident on leaf surfaces in different crown orientations were also measured throughout one entire summer day for each species. Mean daily PPFD values were similar for the leaves from the eastern and western sides of the canopy. On the western side, PPFD reached maximum values during the afternoon. Maximum leaf temperatures were approximately 10-20% higher on the west side, whereas minimum leaf water potentials were between 10 and 24% higher on the east side. Maximum transpiration rates were approximately 22% greater on the west, because of the greater leaf-to-air vapor pressure deficits (LAVPD). Mean individual leaf area was around 10% larger on the east than on the west side of the trees. In contrast, there were no significant differences in LMA between east and west sides of the crown. Contrary to our expectations, more severe water stress on the west side did not result in increases in LMA, although it was associated with lower individual leaf area. We conclude that increases in LMA measured by other authors along gradients of water stress would be due to differences in light intensity between dry and humid sites.

Tree Species Classification of Broadleaved Forests in Nagano, Central Japan, Using Airborne Laser Data and Multispectral Images

NASA Astrophysics Data System (ADS)

Deng, S.; Katoh, M.; Takenaka, Y.; Cheung, K.; Ishii, A.; Fujii, N.; Gao, T.

2017-10-01

This study attempted to classify three coniferous and ten broadleaved tree species by combining airborne laser scanning (ALS) data and multispectral images. The study area, located in Nagano, central Japan, is within the broadleaved forests of the Afan Woodland area. A total of 235 trees were surveyed in 2016, and we recorded the species, DBH, and tree height. The geographical position of each tree was collected using a Global Navigation Satellite System (GNSS) device. Tree crowns were manually detected using GNSS position data, field photographs, true-color orthoimages with three bands (red-green-blue, RGB), 3D point clouds, and a canopy height model derived from ALS data. Then a total of 69 features, including 27 image-based and 42 point-based features, were extracted from the RGB images and the ALS data to classify tree species. Finally, the detected tree crowns were classified into two classes for the first level (coniferous and broadleaved trees), four classes for the second level (Pinus densiflora, Larix kaempferi, Cryptomeria japonica, and broadleaved trees), and 13 classes for the third level (three coniferous and ten broadleaved species), using the 27 image-based features, 42 point-based features, all 69 features, and the best combination of features identified using a neighborhood component analysis algorithm, respectively. The overall classification accuracies reached 90 % at the first and second levels but less than 60 % at the third level. The classifications using the best combinations of features had higher accuracies than those using the image-based and point-based features and the combination of all of the 69 features.

Constraints on physiological function associated with branch architecture and wood density in tropical forest trees

Treesearch

Frederick C. Meinzer; Paula I. Campanello; Jean-Christophe Domec; M. Genoveva Gatti; Guillermo Goldstein; Randol Villalobos-Vega; David R. Woodruff

2008-01-01

This study examined how leaf and stem functional traits related to gas exchange and water balance scale with two potential proxies for tree hydraulic architecture: the leaf area:sapwood area ratio (AL:AS) and wood density (W). We studied the upper crowns of individuals of 15 tropical forest...

Effects of Phytophthora ramorum infection on hydraulic conductivity and tylosis formation in Tanoak sapwood

Treesearch

Jennifer Parke; Bradley Collins; Barb Lachenbruch; Everett Hansen

2010-01-01

Tanoak (Lithocarpus densiflorus) is highly susceptible to sudden oak death caused by Phytophthora ramorum. Symptoms include dying crowns, bleeding cankers, and, eventually, death of infected trees. The cause of mortality is not well understood, but we showed previously that naturally infected mature trees have reduced sap...

THE ROLE OF TYLOSES IN CROWN HYDRAULIC FAILURE OF MATURE WALNUT TREES AFFLICTED WITH APOPLEXY DISORDER

USDA-ARS?s Scientific Manuscript database

In the Central Valley of California, mature walnut trees afflicted with apoplexy disorder exhibit rapid and complete canopy defoliation within a few weeks of symptom initiation. Symptoms are typically found throughout the entire canopy and are initially expressed as wilting and chlorosis followed b...

Distribution of biomass and nutrients in lodgepole pine/bitterbrush ecosystems in central Oregon.

Treesearch

Susan N. Little; Laurl J. Shainsky

1992-01-01

We investigated the distribution of biomass and nutrients in lodgepole pine (Pinus contorta var. murryana Dougl.) ecosystems on pumice soils in south-central Oregon. Sixty-three trees were sampled to develop equations for estimating dry weights of tree crowns, boles, bark, and coarse roots from diameter at breast height and...

Sycamore diseases

Treesearch

F. I. McCracken

1989-01-01

The canker stain disease, one of several fungi that cause cankers of sycamore, can cause serious loss of sycamores in natural stands, plantations, and urban areas. As many as 35 percent of the trees in some stands may be diseased. Affected trees develop thin crowns, twig dieback, small leaves and epicormic branches. The narrow, elongate, bark covered, flat, spiraling...

Development of Sirococcus shoot blight following thinning in western hemlock regeneration.

Treesearch

Charles G. Shaw; Thomas H. Laurent; Spencer Israelson

1981-01-01

Shoot mortality from Sirococcus strobilinus Preuss. and other causes was recorded by crown position from April 1978 through October 1979 in younggrowth western hemlock (Tsuga heterophylla (Raf.) Sarg.) crop trees released in a 1977 thinning at Thomas Bay, Alaska. All study trees contained some infected shoots, but no terminal...

A Metric on Phylogenetic Tree Shapes.

PubMed

Colijn, C; Plazzotta, G

2018-01-01

The shapes of evolutionary trees are influenced by the nature of the evolutionary process but comparisons of trees from different processes are hindered by the challenge of completely describing tree shape. We present a full characterization of the shapes of rooted branching trees in a form that lends itself to natural tree comparisons. We use this characterization to define a metric, in the sense of a true distance function, on tree shapes. The metric distinguishes trees from random models known to produce different tree shapes. It separates trees derived from tropical versus USA influenza A sequences, which reflect the differing epidemiology of tropical and seasonal flu. We describe several metrics based on the same core characterization, and illustrate how to extend the metric to incorporate trees' branch lengths or other features such as overall imbalance. Our approach allows us to construct addition and multiplication on trees, and to create a convex metric on tree shapes which formally allows computation of average tree shapes. © The Author(s) 2017. Published by Oxford University Press, on behalf of the Society of Systematic Biologists.

Leaf area and light use efficiency patterns of Norway spruce under different thinning regimes and age classes

PubMed Central

Gspaltl, Martin; Bauerle, William; Binkley, Dan; Sterba, Hubert

2013-01-01

Silviculture focuses on establishing forest stand conditions that improve the stand increment. Knowledge about the efficiency of an individual tree is essential to be able to establish stand structures that increase tree resource use efficiency and stand level production. Efficiency is often expressed as stem growth per unit leaf area (leaf area efficiency), or per unit of light absorbed (light use efficiency). We tested the hypotheses that: (1) volume increment relates more closely with crown light absorption than leaf area, since one unit of leaf area can receive different amounts of light due to competition with neighboring trees and self-shading, (2) dominant trees use light more efficiently than suppressed trees and (3) thinning increases the efficiency of light use by residual trees, partially accounting for commonly observed increases in post-thinning growth. We investigated eight even-aged Norway spruce (Picea abies (L.) Karst.) stands at Bärnkopf, Austria, spanning three age classes (mature, immature and pole-stage) and two thinning regimes (thinned and unthinned). Individual leaf area was calculated with allometric equations and absorbed photosynthetically active radiation was estimated for each tree using the three-dimensional crown model Maestra. Absorbed photosynthetically active radiation was only a slightly better predictor of volume increment than leaf area. Light use efficiency increased with increasing tree size in all stands, supporting the second hypothesis. At a given tree size, trees from the unthinned plots were more efficient, however, due to generally larger tree sizes in the thinned stands, an average tree from the thinned treatment was superior (not congruent in all plots, thus only partly supporting the third hypothesis). PMID:25540477

A practical introduction to skeletons for the plant sciences1

PubMed Central

Bucksch, Alexander

2014-01-01

Before the availability of digital photography resulting from the invention of charged couple devices in 1969, the measurement of plant architecture was a manual process either on the plant itself or on traditional photographs. The introduction of cheap digital imaging devices for the consumer market enabled the wide use of digital images to capture the shape of plant networks such as roots, tree crowns, or leaf venation. Plant networks contain geometric traits that can establish links to genetic or physiological characteristics, support plant breeding efforts, drive evolutionary studies, or serve as input to plant growth simulations. Typically, traits are encoded in shape descriptors that are computed from imaging data. Skeletons are one class of shape descriptors that are used to describe the hierarchies and extent of branching and looping plant networks. While the mathematical understanding of skeletons is well developed, their application within the plant sciences remains challenging because the quality of the measurement depends partly on the interpretation of the skeleton. This article is meant to bridge the skeletonization literature in the plant sciences and related technical fields by discussing best practices for deriving diameters and approximating branching hierarchies in a plant network. PMID:25202645

Simulation Studies of the Effect of Forest Spatial Structure on InSAR Signature

NASA Technical Reports Server (NTRS)

Sun, Guoqing; Liu, Dawei; Ranson, K. Jon; Koetz, Benjamin

2007-01-01

The height of scattering phase retrieved from InSAR data is considered being correlated with the tree height and the spatial structure of the forest stand. Though some researchers have used simple backscattering models to estimate tree height from the height of scattering center, the effect of forest spatial structure on InSAR data is not well understood yet. A three-dimensional coherent radar backscattering model for forest canopies based on realistic three-dimensional scene was used to investigate the effect in this paper. The realistic spatial structure of forest canopies was established either by field measurements (stem map) or through use of forest growth model. Field measurements or a forest growth model parameterized using local environmental parameters provides information of forest species composition and tree sizes in certain growth phases. A fractal tree model (L-system) was used to simulate individual 3- D tree structure of different ages or heights. Trees were positioned in a stand in certain patterns resulting in a 3-D medium of discrete scatterers. The radar coherent backscatter model took the 3-D forest scene as input and simulates the coherent radar backscattering signature. Interferometric SAR images of 3D scenes were simulated and heights of scattering phase centers were estimated from the simulated InSAR data. The effects of tree height, crown cover, crown depth, and the spatial distribution patterns of trees on the scattering phase center were analyzed. The results will be presented in the paper.

Effects of height and live crown ratio imputation strategies on stand biomass estimation

Treesearch

Elijah J. Allensworth; Temesgen. Hailemariam

2015-01-01

The effects of subsample design and imputation of total height (ht) and live crown ratio (cr) on the accuracy of stand-level estimates of component and total aboveground biomass are not well investigated in the current body of literature. To assess this gap in research, this study uses a data set of 3,454 Douglas-fir trees obtained from 102 stands in southwestern...

Shade images of forested areas obtained from Landsat MSS data

NASA Technical Reports Server (NTRS)

Shimabukuro, Yosio Edemir; Smith, James A.

1989-01-01

The objective of this report is to generate a shade (shadow) image of forested areas from Landsat MSS data by implementing a linear mixing model, where shadow is considered as one of the primary components in a pixel. The shade images are related to the observed variation in forest structure; i.e., the proportion of inferred shadow in a pixel is related to different forest ages, forest types, and tree crown cover. The constrained least-squares method is used to generate shade images for forest of eucalyptus and vegetation of 'cerrado' over the Itapeva study area in Brazil. The resulted shade images may explain the difference on ages for forest of eucalyptus and the difference on tree crown cover for vegetation of cerrado.

Spatio-temporal water dynamics in mature Banksia menziesii trees during drought.

PubMed

Bader, Martin K-F; Ehrenberger, Wilhelm; Bitter, Rebecca; Stevens, Jason; Miller, Ben P; Chopard, Jerome; Rüger, Simon; Hardy, Giles E S J; Poot, Pieter; Dixon, Kingsley W; Zimmermann, Ulrich; Veneklaas, Erik J

2014-10-01

Southwest Australian Banksia woodlands are highly diverse plant communities that are threatened by drought- or temperature-induced mortality due to the region's changing climate. We examined water relations in dominant Banksia menziesii R. Br. trees using magnetic leaf patch clamp pressure (ZIM-) probes that allow continuous, real-time monitoring of leaf water status. Multiple ZIM-probes across the crown were complemented by traditional ecophysiological measurements. During summer, early stomatal downregulation of transpiration prevented midday balancing pressures from exceeding 2.5 MPa. Diurnal patterns of ZIM-probe and pressure chamber readings agreed reasonably well, however, ZIM-probes recorded short-term dynamics, which are impossible to capture using a pressure chamber. Simultaneous recordings of three ZIM-probes evenly spaced along leaf laminas revealed intrafoliar turgor gradients, which, however, did not develop in a strictly basi- or acropetal fashion and varied with cardinal direction. Drought stress manifested as increasing daily signal amplitude (low leaf water status) and occasionally as rising baseline at night (delayed rehydration). These symptoms occurred more often locally than across the entire crown. Microclimate effects on leaf water status were strongest in crown regions experiencing peak morning radiation (East and North). Extreme spring temperatures preceded the sudden death of B. menziesii trees, suggesting a temperature- or humidity-related tipping point causing rapid hydraulic failure as evidenced by collapsing ZIM-probe readings from an affected tree. In a warmer and drier future, increased frequency of B. menziesii mortality will result in significantly altered community structure and ecosystem function. © 2014 Scandinavian Plant Physiology Society.

Classification of savanna tree species, in the Greater Kruger National Park region, by integrating hyperspectral and LiDAR data in a Random Forest data mining environment

NASA Astrophysics Data System (ADS)

Naidoo, L.; Cho, M. A.; Mathieu, R.; Asner, G.

2012-04-01

The accurate classification and mapping of individual trees at species level in the savanna ecosystem can provide numerous benefits for the managerial authorities. Such benefits include the mapping of economically useful tree species, which are a key source of food production and fuel wood for the local communities, and of problematic alien invasive and bush encroaching species, which can threaten the integrity of the environment and livelihoods of the local communities. Species level mapping is particularly challenging in African savannas which are complex, heterogeneous, and open environments with high intra-species spectral variability due to differences in geology, topography, rainfall, herbivory and human impacts within relatively short distances. Savanna vegetation are also highly irregular in canopy and crown shape, height and other structural dimensions with a combination of open grassland patches and dense woody thicket - a stark contrast to the more homogeneous forest vegetation. This study classified eight common savanna tree species in the Greater Kruger National Park region, South Africa, using a combination of hyperspectral and Light Detection and Ranging (LiDAR)-derived structural parameters, in the form of seven predictor datasets, in an automated Random Forest modelling approach. The most important predictors, which were found to play an important role in the different classification models and contributed to the success of the hybrid dataset model when combined, were species tree height; NDVI; the chlorophyll b wavelength (466 nm) and a selection of raw, continuum removed and Spectral Angle Mapper (SAM) bands. It was also concluded that the hybrid predictor dataset Random Forest model yielded the highest classification accuracy and prediction success for the eight savanna tree species with an overall classification accuracy of 87.68% and KHAT value of 0.843.

Sapling structure and regeneration strategy in 18 Shorea species co-occurring in a tropical rainforest.

PubMed

Aiba, Masahiro; Nakashizuka, Tohru

2005-08-01

Inevitable trade-offs in structure may be a basis for differentiation in plant strategies. Juvenile trees in different functional groups are characterized by specific suites of structural traits such as crown architecture and biomass distribution. The relationship between juvenile tree structure and function was tested to find out if it is robust among functionally and taxonomically similar species of the genus Shorea that coexist sympatrically in a tropical rain forest in Borneo. The sapling structures of 18 species were compared for standardized dry masses of 5 and 30 g. Pairwise simple correlation and multiple correlation patterns among structural traits of juveniles (0.1-1.5 m in height) of 18 Shorea species were examined using Pearson's correlation and principal component analysis (PCA), respectively. The correlation was then tested between the PCA results and three indices of shade tolerance: the net photosynthetic rate, the wood density of mature trees and seed size. The structural variation in saplings of the genus Shorea was as large as that found in sets of species with much more diverse origins. The PCA showed that both crown architecture and allocation to leaves are major sources of variation in the structures of the 18 species investigated. Of these two axes, allocation to leaves was significantly correlated with wood density and showed a limited correlation with photosynthetic rate, whereas crown architecture was significantly correlated to seed size. Overall, the results suggest that an allocation trade-off between leaves and other organs, which co-varied with wood density and to a certain extent with photosynthetic capacity, accounts for the difference in shade tolerance among congeneric, functionally similar species. In contrast, the relationship between the architecture and regeneration strategy differed from the pattern found between functional groups, and the function of crown architecture was ambiguous.

Area-Wide Analysis of Hardwood Defoliator Effects on Tree Conditions in the Allegheny Plateau

Treesearch

Randall S. Morin; Andrew M. Liebhold; Kurt W. Gottschalk

2004-01-01

The effects of defoliation caused by three foliage feeding insects, the gypsy moth (Lymantria dispar), the cherry scallopshell moth (Hydria prunivorata), and the elm spanworm (Ennomos subsignarius), on tree mortality and crown conditions were evaluated using data collected from 1984 to 1999 in the Allegheny National Forest located in northwestern Pennsylvania. While...

Spatial continuity of tree attributes in bottomland hardwood forests in the Southeastern United States

Treesearch

Luben D. Dimov; Jim L. Chambers; Brian Roy Lockhart

2005-01-01

Sustainable forest management and conservation require understanding of underlying basic structural and competitive relationships. To gain insight into these relationships, we analyzed spatial continuity of tree basal area (BA) and crown projection area (CPA) on twelve 0.64-ha plots in four mixed bottomland hardwood stands in Louisiana, Arkansas, and Mississippi....

Reliability assessment of selected indicators of tree health

Treesearch

Pawel M. Lech

2000-01-01

The measurements of electrical resistance of near-cambium tissues, selected biometric features of needles and shoots, and the annual radial increment as well as visual estimates of crown defoliation were performed on about 100 Norway spruce trees in three 60- to 70-year-old stands located in the Western Sudety Mountains. The defoliation, electrical resistance, and...

Physiological and Growth Responses of Midrotation Loblolly Pine to Treatments of Fire, Herbicide, and Fertilizer

Treesearch

Emily J. Goodwin; Lisa M. Marino McInnis; Hans M. Williams; Brian P. Oswald; Kenneth W. Farrish

2004-01-01

The objectives of this study were to examine the effects of fertilizer and understory vegetation control (herbicide and prescribed fire) on mature tree physiology and to link observed physiological responses with tree growth. Photosynthetic rate (photosynthesis), transpiration, stomatal conductance, stem diameter, and crown area were measured in two midrotation...

Crown release increases growth of crop trees

Treesearch

Neil I. Lamson; H. Clay Smith; Arlyn W. Perkey; Samuel M. Brock; Samuel M. Brock

1990-01-01

Two Appalachian hardwood stands in north-central West Virginia were thinned. The principal species were red oak, yellow-poplar, and chestnut oak. For both stands the site index for northern red oak averaged 75 feet. An areawide thinning using "basal-area control" was applied to a 54-yearold stand while specific crop trees were selected and released in a 12-...

Prediction of height increment for models of forest growth

Treesearch

Albert R. Stage

1975-01-01

Functional forms of equations were derived for predicting 10-year periodic height increment of forest trees from height, diameter, diameter increment, and habitat type. Crown ratio was considered as an additional variable for prediction, but its contribution was negligible. Coefficients of the function were estimated for 10 species of trees growing in 10 habitat types...

Physiological and foliar symptom response of Prunus serotina, Fraxinus americana and Acer rubrum canopy trees to ozone under differing site conditions

Treesearch

M. Schaub; J.M. Skelly; J.W. Zhang; J.A. Ferdinand; J.E. Savage; R.E. Stevenson; D.D. Davis; K.C. Steiner

2005-01-01

The crowns of five canopy dominant black cherry ( Prunus serotina Ehrh.), five white ash ( Fraxinus americana L.), and six red maple ( Acer rubrum L.) trees on naturally differing environmental conditions were accessed with scaffold towers within a mixed hardwood forest stand in central Pennsylvania....

Promoting Reduced-Impact Logging in Tropical Developing Countries: A Success Story of Technology Transfer

Treesearch

Dennis P. Dykstra

2007-01-01

Industrial timber harvesting operations commonly employ heavy machinery and thus have the potential to inflict significant damage on soils, streams, and residual vegetation. Impacts associated with such operations have been especially troubling in many tropical countries, where mature trees often have large crowns capable of destroying other trees when they fall; soils...

Aluminum-induced calcium deficiency syndrome in declining red spruce

Treesearch

Walter C. Shortle; Kevin T. Smith

1988-01-01

Prolonged suppression of cambial growth has apparently caused a decline in radial growth in many mature red spruce, Picea rubens. Surveys indicate that this decline occurs in trees throughout the natural range of red spruce and is independent of elevation, tree size, and age class. In addition, crowns of mature red spruce at high elevations across...

Root biomechanics in Rhizophora mangle: anatomy, morphology and ecology of mangrove's flying buttresses.

PubMed

Méndez-Alonzo, Rodrigo; Moctezuma, Coral; Ordoñez, Víctor R; Angeles, Guillermo; Martínez, Armando J; López-Portillo, Jorge

2015-04-01

Rhizophora species of mangroves have a conspicuous system of stilt-like roots (rhizophores) that grow from the main stem and resemble flying buttresses. As such, the development of rhizophores can be predicted to be important for the effective transmission of dynamic loads from the top of the tree to the ground, especially where the substrate is unstable, as is often the case in the habitats where Rhizophora species typically grow. This study tests the hypothesis that rhizophore architecture in R. mangle co-varies with their proximity to the main stem, and with stem size and crown position. The allometry and wood mechanical properties of R. mangle (red mangrove) trees growing in a mangrove basin forest within a coastal lagoon in Mexico were compared with those of coexisting, non-buttressed mangrove trees of Avicennia germinans. The anatomy of rhizophores was related to mechanical stress due to crown orientation (static load) and to prevailing winds (dynamic load) at the study site. Rhizophores buttressed between 10 and 33 % of tree height. There were significant and direct scaling relationships between the number, height and length of rhizophores vs. basal area, tree height and crown area. Wood mechanical resistance was significantly higher in the buttressed R. mangle (modulus of elasticity, MOE = 18·1 ± 2 GPa) than in A. germinans (MOE = 12·1 ± 0·5 GPa). Slenderness ratios (total height/stem diameter) were higher in R. mangle, but there were no interspecies differences in critical buckling height. When in proximity to the main stem, rhizophores had a lower length/height ratio, higher eccentricity and higher xylem/bark and pith proportions. However, there were no directional trends with regard to prevailing winds or tree leaning. In comparison with A. germinans, a tree species with wide girth and flare at the base, R. mangle supports a thinner stem of higher mechanical resistance that is stabilized by rhizophores resembling flying buttresses. This provides a unique strategy to increase tree slenderness and height in the typically unstable substrate on which the trees grow, at a site that is subject to frequent storms. © The Author 2015. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

A discrete element modelling approach for block impacts on trees

NASA Astrophysics Data System (ADS)

Toe, David; Bourrier, Franck; Olmedo, Ignatio; Berger, Frederic

2015-04-01

These past few year rockfall models explicitly accounting for block shape, especially those using the Discrete Element Method (DEM), have shown a good ability to predict rockfall trajectories. Integrating forest effects into those models still remain challenging. This study aims at using a DEM approach to model impacts of blocks on trees and identify the key parameters controlling the block kinematics after the impact on a tree. A DEM impact model of a block on a tree was developed and validated using laboratory experiments. Then, key parameters were assessed using a global sensitivity analyse. Modelling the impact of a block on a tree using DEM allows taking into account large displacements, material non-linearities and contacts between the block and the tree. Tree stems are represented by flexible cylinders model as plastic beams sustaining normal, shearing, bending, and twisting loading. Root soil interactions are modelled using a rotation stiffness acting on the bending moment at the bottom of the tree and a limit bending moment to account for tree overturning. The crown is taken into account using an additional mass distribute uniformly on the upper part of the tree. The block is represented by a sphere. The contact model between the block and the stem consists of an elastic frictional model. The DEM model was validated using laboratory impact tests carried out on 41 fresh beech (Fagus Sylvatica) stems. Each stem was 1,3 m long with a diameter between 3 to 7 cm. Wood stems were clamped on a rigid structure and impacted by a 149 kg charpy pendulum. Finally an intensive simulation campaign of blocks impacting trees was done to identify the input parameters controlling the block kinematics after the impact on a tree. 20 input parameters were considered in the DEM simulation model : 12 parameters were related to the tree and 8 parameters to the block. The results highlight that the impact velocity, the stem diameter, and the block volume are the three input parameters that control the block kinematics after impact.

Response to crop-tree release by 7-year-old stems of red maple stump sprouts and northern red oak advance reproduction

Treesearch

G. R., Jr. Trimble

1974-01-01

This paper deals with crop-tree release sf two species typical of a fair site: red maple stump sprouts and northern red oak advance reproduction. A study was made to test the feasibility of doing a crop-tree release immediately after the canopy closed and crown classes could be distinguished. The study was made in a 7-year-old even-aged hardwood stand on the Fernow...

Visible ozone injury on mature black cherry in two Class I wilderness areas

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

Chappelka, A.; Skelly, J.; Hildebrand, E.

1995-12-31

During the summer of 1991--1993, the incidence and severity of foliar symptoms due to ambient ozone exposures were documented on mature black cherry (Prunus serotina) in two Class 1 areas in the Appalachian mountains of the eastern US: Great Smoky Mountains National Park (GRSM) and Shenandoah National Park (SHEN). Three plots in each park containing 30 trees each (Big Meadows in SHEN had 60 trees evaluated each year) with 90 and 120 trees evaluated per GRSM and SHEN, respectively. Plots were established adjacent to ozone monitoring stations at different elevations. Samples of foliage from trees were collected by tree climbersmore » and three exposed branches from the upper crown and three branches form the mid-to-lower crown were evaluated for symptoms of foliar injury due to ozone. Incidence was the greatest in 1991 at both locations; 45% and 60% for SHEN and GRSM, respectively. In 1992 and 1993, incidence was very similar in both parks, with approximately 33% of the trees affected. Black cherry at the highest elevations exhibited the greatest amount of symptoms in both parks all three years of investigation. These sites also exhibited the highest levels of ozone. The results indicate that visible injury due to ambient ozone is prevalent in Class 1 areas in the eastern US, indicative of the nature of this regional phytotoxicant.« less

Thigmomorphogenesis: field and laboratory studies of Abies fraseri in response to wind or mechanical perturbation

NASA Technical Reports Server (NTRS)

Telewski, F. W.; Jaffe, M. J.

1986-01-01

Field- and greenhouse-grown Abies fraseri (Pursh) Poir. (Fraser fir) were analyzed for wind- or mechanically-induced flexure changes. These changes included inhibition of stem and needle elongation, reinforcement of branch bases around the stem, and increased radial growth in the direction of the mechanical perturbation (MP). Mature trees exposed to high wind conditions were severely flag-formed. These modified tree crowns had a lower drag than crowns of non-flag formed trees in wind-tunnel tests. In both field-grown and greenhouse-grown A. fraseri, MP induced a decrease in flexibility and increased elasticity of the stems. The increased radial growth of the stems overrode the increase in elasticity, resulting in the overall decrease in flexibility. The increase in radial growth caused by wind or mechanical flexure was due to greater cell divisions of the vascular cambium, resulting in increased numbers of tracheids. The decrease in stem elongation in these trees was due, at least in part, to a decrease in tracheid length. The potential biological and mechanical significance of these induced growth changes in trees are addressed. The data support the thigmomorphogenetic theory, which states that plants respond to wind and other mechanical perturbations in a way that is favorable to the plant for continued survival in windy environments.

Thigmomorphogenesis: field and laboratory studies of Abies fraseri in response to wind or mechanical perturbation.

PubMed

Telewski, F W; Jaffe, M J

1986-01-01

Field- and greenhouse-grown Abies fraseri (Pursh) Poir. (Fraser fir) were analyzed for wind- or mechanically-induced flexure changes. These changes included inhibition of stem and needle elongation, reinforcement of branch bases around the stem, and increased radial growth in the direction of the mechanical perturbation (MP). Mature trees exposed to high wind conditions were severely flag-formed. These modified tree crowns had a lower drag than crowns of non-flag formed trees in wind-tunnel tests. In both field-grown and greenhouse-grown A. fraseri, MP induced a decrease in flexibility and increased elasticity of the stems. The increased radial growth of the stems overrode the increase in elasticity, resulting in the overall decrease in flexibility. The increase in radial growth caused by wind or mechanical flexure was due to greater cell divisions of the vascular cambium, resulting in increased numbers of tracheids. The decrease in stem elongation in these trees was due, at least in part, to a decrease in tracheid length. The potential biological and mechanical significance of these induced growth changes in trees are addressed. The data support the thigmomorphogenetic theory, which states that plants respond to wind and other mechanical perturbations in a way that is favorable to the plant for continued survival in windy environments.

An experimental demonstration of stem damage as a predictor of fire-caused mortality for ponderosa pine

USGS Publications Warehouse

van Mantgem, P.; Schwartz, M.

2004-01-01

We subjected 159 small ponderosa pine (Pinus ponderosa Dougl. ex P. & C. Laws.) to treatments designed to test the relative importance of stem damage as a predictor of postfire mortality. The treatments consisted of a group with the basal bark artificially thinned, a second group with fuels removed from the base of the stem, and an untreated control. Following prescribed burning, crown scorch severity was equivalent among the groups. Postfire mortality was significantly less frequent in the fuels removal group than in the bark removal and control groups. No model of mortality for the fuels removal group was possible, because dead trees constituted <4% of subject trees. Mortality in the bark removal group was best predicted by crown scorch and stem scorch severity, whereas death in the control group was predicted by crown scorch severity and bark thickness. The relative lack of mortality in the fuels removal group and the increased sensitivity to stem damage in the bark removal group suggest that stem damage is a critical determinant of postfire mortality for small ponderosa pine.

Early height growth of ponderosa pine forecasts dominance in plantations

Treesearch

William W. Oliver; Robert F. Powers

1971-01-01

Future crown class may be determined well in advance of intertree competition in plantation grown ponderosa pine. Regardless of site quality, dominant trees in 10 California plantations reached breast height ½ year sooner than codominants and 1-½ years sooner than intermediates. Dominant trees on poor sites reached breast height several years earlier than has been...

Effects of seasonal prescribved fires on residual overstory trees in oak-dominate shelterwood stands

Treesearch

Patrick H. Brose; David H. Van Lear

1999-01-01

A study was initiated in 1994 to evaluate the degree of bole damage and crown decline residual overstory trees would experience because of prescribed burning of shelterwood stands. Three oak-dominated shelterwood stands, partially harvested 2 to 4 yr earlier, were divided into four treatments (unburned control, spring burn, summer burn, and winter burn). Fifteen...

Development of a highly automated system for the remote evaluation of individual tree parameters

Treesearch

Richard Pollock

2000-01-01

A highly-automated procedure for remotely estimating individual tree location, crown diameter, species class, and height has been developed. This procedure will involve the use of a multimodal airborne sensing system that consists of a digital frame camera, a scanning laser rangefinder, and a position and orientation measurement system. Data from the multimodal sensing...

Spatial distribution and succession of epiphytes on Tsuga heterophylla (western hemlock) in an old-growth Douglas-fir forest

Treesearch

Betsy Lyons; Nalini M. Nadkarni; Malcolm P. North

2000-01-01

We examined the distribution and abundance of nonvascular epiphytes on western hemlock trees in an oldgrowth coniferous forest focusing on patterns of epiphyte distribution at different spatial scales, epiphyte abundance amongst trees differing in size, and crown structures associated with epiphyte abundance. Total epiphyte cover was greatest in four canopy...

Associations of calcium and aluminum with the growth and health of sugar maple trees in Vermont

Treesearch

Paul G. Schaberg; James W. Tilley; Gary J. Hawley; Donald H. DeHayes; Scott W. Bailey

2006-01-01

We compared tree growth and crown condition with soil and foliar elemental composition in 14 sugar maple (Acer saccharum Marsh.) stands in VT, USA, to evaluate if deficiencies or imbalances in cation nutrition were associated with growth and health reductions in native stands. The Till Source Model (TSM) was used to select study sites potentially...

Handbook for predicting slash weight of trees in the Northeast.

Treesearch

Duane R. Freeman; Robert M. Loomis; Peter J. Roussopoulos

1982-01-01

Tables are provided for estimating tree crown weights based on species and diameters (d.b.h.) for 10 conifer and 9 hardwood species or species groups of the North Central and Northeastern United States. Procedures are given for predicting slash weights resulting from: cutting timber, trampling during logging activities, and defect and breakage left on the site after...

Biotic mortality factors affecting emerald ash borer (Agrilus planipennis) are highly dependent on life stage and host tree crown condition

USDA-ARS?s Scientific Manuscript database

Emerald ash borer (EAB), Agrilus planipennis, is a serious invasive forest pest in North America responsible for killing tens to hundreds of millions of ash trees since it was accidentally introduced in the 1990’s. Although host plant resistance and natural enemies are known to be important sources ...

Equations for estimating loblolly pine branch and foliage weight and surface area distributions

Treesearch

V. Clark Baldwin; Kelly D. Peterson; Harold E. Burkhatt; Ralph L. Amateis; Phillip M. Dougherty

1996-01-01

Equations to predict foliage weight and surface area, and their vertical and horizontal distributions, within the crowns of unthinned loblolly pine (Pinus tueduL.) trees are presented. A right-truncated Weibull function was used for describing vertical foliage distributions. This function ensures that all of the foliage located between the tree tip and the foliage base...

Quantifying the legacy of foliar winter injury on woody aboveground carbon sequestration of red spruce trees

Treesearch

Alexandra M. Kosiba; Paul G. Schaberg; Gary J. Hawley; Christopher F. Hansen

2013-01-01

Red spruce (Picea rubens Sarg.) decline has been quantitatively attributed to foliar winter injury caused by freezing damage. The results of this injury include foliar mortality, crown deterioration, and negative carbon (C) balances that can lead to tree health declines and eventual mortality. In 2003, a severe region-wide event damaged over 90% of...

Fire effects on tree overstories in the oak savannas of the Southwestern Borderlands Region

Treesearch

Peter F. Ffolliott; Gerald J. Gottfried; Cody L. Stropki; Hui Chen; Daniel G. Neary

2011-01-01

Effects of cool-season and warm-season prescribed burning treatments and a wildfire on tree overstories in oak savannas on the Cascabel Watersheds of the Southwestern Borderlands Region are reported in this paper. Information on the initial survival, levels of crown damage, species compositions and densities, annual growth rates, and basal sprouting following these...

Reproducibility and Reliability: How To Define the Population of Trees That Represent Site Quality For Longleaf Pine Plantations

Treesearch

J.C.G. Goelz; Daniel J. Leduc

2004-01-01

We compared 13 definitions for the subpopulation of “site trees.” Each subpopulation was defined (1) once at base age or at each measurement; (2) by crown class, diameter, or height; and (3) by the number of trees per acre. These subpopulations were applied to base ages of 25 and 50. For base age 25, the subpopulations defined at base age were superior to those defined...

Modelling individual tree height to crown base of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.)

PubMed Central

Jansa, Václav

2017-01-01

Height to crown base (HCB) of a tree is an important variable often included as a predictor in various forest models that serve as the fundamental tools for decision-making in forestry. We developed spatially explicit and spatially inexplicit mixed-effects HCB models using measurements from a total 19,404 trees of Norway spruce (Picea abies (L.) Karst.) and European beech (Fagus sylvatica L.) on the permanent sample plots that are located across the Czech Republic. Variables describing site quality, stand density or competition, and species mixing effects were included into the HCB model with use of dominant height (HDOM), basal area of trees larger in diameters than a subject tree (BAL- spatially inexplicit measure) or Hegyi’s competition index (HCI—spatially explicit measure), and basal area proportion of a species of interest (BAPOR), respectively. The parameters describing sample plot-level random effects were included into the HCB model by applying the mixed-effects modelling approach. Among several functional forms evaluated, the logistic function was found most suited to our data. The HCB model for Norway spruce was tested against the data originated from different inventory designs, but model for European beech was tested using partitioned dataset (a part of the main dataset). The variance heteroscedasticity in the residuals was substantially reduced through inclusion of a power variance function into the HCB model. The results showed that spatially explicit model described significantly a larger part of the HCB variations [R2adj = 0.86 (spruce), 0.85 (beech)] than its spatially inexplicit counterpart [R2adj = 0.84 (spruce), 0.83 (beech)]. The HCB increased with increasing competitive interactions described by tree-centered competition measure: BAL or HCI, and species mixing effects described by BAPOR. A test of the mixed-effects HCB model with the random effects estimated using at least four trees per sample plot in the validation data confirmed that the model was precise enough for the prediction of HCB for a range of site quality, tree size, stand density, and stand structure. We therefore recommend measuring of HCB on four randomly selected trees of a species of interest on each sample plot for localizing the mixed-effects model and predicting HCB of the remaining trees on the plot. Growth simulations can be made from the data that lack the values for either crown ratio or HCB using the HCB models. PMID:29049391

Spatial effects of aboveground biomass on soil ecological parameters and trace gas fluxes in a savannah ecosystem of Mount Kilimanjaro

NASA Astrophysics Data System (ADS)

Becker, Joscha; Gütlein, Adrian; Sierra Cornejo, Natalia; Kiese, Ralf; Hertel, Dietrich; Kuzyakov, Yakov

2015-04-01

The savannah biome is a hotspot for biodiversity and wildlife conservation in Africa and recently got in the focus of research on carbon sequestration. Savannah ecosystems are under strong pressure from climate and land-use change, especially around populous areas like the Mt. Kilimanjaro region. Savannah vegetation in this area consists of grassland with isolated trees and is therefore characterized by high spatial variation of canopy cover, aboveground biomass and root structure. Canopy structure is known to affect microclimate, throughfall and evapotranspiration and thereby controls soil moisture conditions. Consequently, the canopy structure is a major regulator for soil ecological parameters and soil-atmospheric trace gas exchange (CO2, N2O, CH4) in water limited environments. The spatial distribution of these parameters and the connection between above and belowground processes are important to understand and predict ecosystem changes and estimate its vulnerability. Our objective was to determine trends and changes of soil parameters and relate their spatial variability to the vegetation structure. We chose three trees from each of the two most dominant species (Acacia nilotica and Balanites aegyptiaca) in our research area. For each tree, we selected transects with nine sampling points of the same relative distances to the stem. Distances were calculated in relation to the crown radius. At these each sampling point a soil core was taken and separated in 0-10 cm and 10-30 cm depth. We measured soil carbon (C) and nitrogen (N) storage, microbial biomass carbon C and N, soil respiration as well as root biomass and -density, soil temperature and soil water content. Each tree was characterized by crown spread, leaf area index and basal area. Preliminary results show that C and N stocks decreased about 50% with depth independently of distance to the tree. Soil water content under the tree crown increased with depth while it decreased under grass cover. Microbial Biomass C and N in the upper 10 cm decreased with distance (C: r²=0.22, p<0.001; N: r²=0.3, p<0.001) as well as total soil respiration. This decrease was affected by tree size but independent from tree species. We conclude that savannah ecosystems exhibit a large spatial variability of soil parameters within the upper horizons which is strongly depend on the structure of aboveground biomass.

Vegetation Structure Controls Carbon Sequestration Potential in a Savannah Ecosystem of Mt. Kilimanjaro Region

NASA Astrophysics Data System (ADS)

Becker, J. N.; Gutlein, A.; Sierra Cornejo, N.; Ralf, K.; Hertel, D.; Kuzyakov, Y.

2016-12-01

The savannah biome is a hotspot for biodiversity and wildlife conservation in Africa and recently got in the focus of research on carbon (C) sequestration. Savanna ecosystems are increasingly pressured by climate and land-use changes, especially around populous areas such as the Mt. Kilimanjaro region. Savanna vegetation consists of grassland with isolated trees and is therefore characterized by high spatial variation and patchiness of canopy cover and aboveground biomass. Both are major regulators for soil ecological properties and soil-atmospheric trace gas exchange (CO2, N2O, CH4), especially in water-limited environments. Our objectives were to determine spatial trends in soil properties and trace-gas fluxes during the dry season and to relate above- and belowground processes and attributes. We chose three trees from each of the two most dominant species (Acacia nilotica and Balanites aegyptiaca) in our research area. For each tree, we selected transects with nine sampling points of the same relative distances to the stem. At each sampling point (0-10 & 10-30 cm depth) we measured soil C and nitrogen (N) storage, microbial biomass C and N, Natural δ13C, soil respiration, available nutrients, pH, cation exchange capacity (CEC) as well as root biomass and -density, soil temperature and soil water content. The tree species had no effect on soil parameters and gas fluxes under the crown. CEC, C and N fractions decreased up to 50% outside the crown-covered area. Tree leaf litter had a far lower C:N ratio than leaf litter of the C4-grass species. δ13C in soil under the crowns shifted about 15% in the direction of tree leaf litter δ13C compared to soil in open area reflecting the tree litter contribution to soil organic matter. The microbial C:N ratio and CO2 efflux were about 30% higher in the open area and strongly dependent on mineral N availability. This indicates N limitation and low C-use efficiency in soil under open grassland. We conclude that the spatial structure of aboveground biomass in savanna ecosystems leads to a spatial redistribution of nutrient availability and thus in C mineralization and sequestration. Therefore, the capability of savanna ecosystems to act as C sinks is both directly and indirectly dependent on the abundance of trees regardless of their N-fixing capability.

Transpiration of urban trees and its cooling effect in a high latitude city.

PubMed

Konarska, Janina; Uddling, Johan; Holmer, Björn; Lutz, Martina; Lindberg, Fredrik; Pleijel, Håkan; Thorsson, Sofia

2016-01-01

An important ecosystem service provided by urban trees is the cooling effect caused by their transpiration. The aim of this study was to quantify the magnitude of daytime and night-time transpiration of common urban tree species in a high latitude city (Gothenburg, Sweden), to analyse the influence of weather conditions and surface permeability on the tree transpiration, and to find out whether tree transpiration contributed to daytime or nocturnal cooling. Stomatal conductance and leaf transpiration at day and night were measured on mature street and park trees of seven common tree species in Gothenburg: Tilia europaea, Quercus robur, Betula pendula, Acer platanoides, Aesculus hippocastanum, Fagus sylvatica and Prunus serrulata. Transpiration increased with vapour pressure deficit and photosynthetically active radiation. Midday rates of sunlit leaves ranged from less than 1 mmol m(-2) s(-1) (B. pendula) to over 3 mmol m(-2) s(-1) (Q. robur). Daytime stomatal conductance was positively related to the fraction of permeable surfaces within the vertically projected crown area. A simple estimate of available rainwater, comprising of precipitation sum and fractional surface permeability within the crown area, was found to explain 68% of variation in midday stomatal conductance. Night-time transpiration was observed in all studied species and amounted to 7 and 20% of midday transpiration of sunlit and shaded leaves, respectively. With an estimated night-time latent heat flux of 24 W m(-2), tree transpiration significantly increased the cooling rate around and shortly after sunset, but not later in the night. Despite a strong midday latent heat flux of 206 W m(-2), a cooling effect of tree transpiration was not observed during the day.

Transpiration of urban trees and its cooling effect in a high latitude city

NASA Astrophysics Data System (ADS)

Konarska, Janina; Uddling, Johan; Holmer, Björn; Lutz, Martina; Lindberg, Fredrik; Pleijel, Håkan; Thorsson, Sofia

2016-01-01

An important ecosystem service provided by urban trees is the cooling effect caused by their transpiration. The aim of this study was to quantify the magnitude of daytime and night-time transpiration of common urban tree species in a high latitude city (Gothenburg, Sweden), to analyse the influence of weather conditions and surface permeability on the tree transpiration, and to find out whether tree transpiration contributed to daytime or nocturnal cooling. Stomatal conductance and leaf transpiration at day and night were measured on mature street and park trees of seven common tree species in Gothenburg: Tilia europaea, Quercus robur, Betula pendula, Acer platanoides, Aesculus hippocastanum, Fagus sylvatica and Prunus serrulata. Transpiration increased with vapour pressure deficit and photosynthetically active radiation. Midday rates of sunlit leaves ranged from less than 1 mmol m-2 s-1 ( B. pendula) to over 3 mmol m-2 s-1 ( Q. robur). Daytime stomatal conductance was positively related to the fraction of permeable surfaces within the vertically projected crown area. A simple estimate of available rainwater, comprising of precipitation sum and fractional surface permeability within the crown area, was found to explain 68 % of variation in midday stomatal conductance. Night-time transpiration was observed in all studied species and amounted to 7 and 20 % of midday transpiration of sunlit and shaded leaves, respectively. With an estimated night-time latent heat flux of 24 W m-2, tree transpiration significantly increased the cooling rate around and shortly after sunset, but not later in the night. Despite a strong midday latent heat flux of 206 W m-2, a cooling effect of tree transpiration was not observed during the day.

Accuracy and equivalence testing of crown ratio models and assessment of their impact on diameter growth and basal area increment predictions of two variants of the Forest Vegetation Simulator

Treesearch

Laura P. Leites; Andrew P. Robinson; Nicholas L. Crookston

2009-01-01

Diameter growth (DG) equations in many existing forest growth and yield models use tree crown ratio (CR) as a predictor variable. Where CR is not measured, it is estimated from other measured variables. We evaluated CR estimation accuracy for the models in two Forest Vegetation Simulator variants: the exponential and the logistic CR models used in the North...

Comparison of leaf gas exchange and stable isotope signature of water-soluble compounds along canopy gradients of co-occurring Douglas-fir and European beech.

PubMed

Bögelein, Rebekka; Hassdenteufel, Martin; Thomas, Frank M; Werner, Willy

2012-07-01

Combined δ(13) C and δ(18) O analyses of water-soluble leaf and twig phloem material were used to determine intrinsic water-use efficiency (iWUE) and variability of stomatal conductance at different crown positions in adult European beech (Fagus sylvatica) and Douglas-fir (Pseudotsuga menziesii) trees. Simultaneous gas exchange measurements allowed evaluation of the differences in calculating iWUE from leaf or phloem water-soluble compounds, and comparison with a semi-quantitative dual isotope model to infer variability of net photosynthesis (A(n) ) between the investigated crown positions. Estimates of iWUE from δ(13) C of leaf water-soluble organic matter (WSOM) outperformed the estimates from phloem compounds. In the beech crown, δ(13) C of leaf WSOM coincided clearly with gas exchange measurements. The relationship was not as reliable in the Douglas-fir. The differences in δ(18) O between leaf and phloem material were found to correlate with stomatal conductance. The semi-quantitative model approach was applicable for comparisons of daily average A(n) between different crown positions and trees. Intracanopy gradients were more pronounced in the beech than in the Douglas-fir, which reached higher values of iWUE at the respective positions, particularly under dry air conditions. © 2012 Blackwell Publishing Ltd.

Satellite image analysis for surveillance, vegetation and climate change

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

Cai, D Michael

2011-01-18

Recently, many studies have provided abundant evidence to show the trend of tree mortality is increasing in many regions, and the cause of tree mortality is associated with drought, insect outbreak, or fire. Unfortunately, there is no current capability available to monitor vegetation changes, and correlate and predict tree mortality with CO{sub 2} change, and climate change on the global scale. Different survey platforms (methods) have been used for forest management. Typical ground-based forest surveys measure tree stem diameter, species, and alive or dead. The measurements are low-tech and time consuming, but the sample sizes are large, running into millionsmore » of trees, covering large areas, and spanning many years. These field surveys provide powerful ground validation for other survey methods such as photo survey, helicopter GPS survey, and aerial overview survey. The satellite imagery has much larger coverage. It is easier to tile the different images together, and more important, the spatial resolution has been improved such that close to or even higher than aerial survey platforms. Today, the remote sensing satellite data have reached sub-meter spatial resolution for panchromatic channels (IKONOS 2: 1 m; Quickbird-2: 0.61 m; Worldview-2: 0.5 m) and meter spatial resolution for multi-spectral channels (IKONOS 2: 4 meter; Quickbird-2: 2.44 m; Worldview-2: 2 m). Therefore, high resolution satellite imagery can allow foresters to discern individual trees. This vital information should allow us to quantify physiological states of trees, e.g. healthy or dead, shape and size of tree crowns, as well as species and functional compositions of trees. This is a powerful data resource, however, due to the vast amount of the data collected daily, it is impossible for human analysts to review the imagery in detail to identify the vital biodiversity information. Thus, in this talk, we will discuss the opportunities and challenges to use high resolution satellite imagery and machine learning theory to monitor tree mortality at the level of individual trees.« less

Woodland Mapping at Single-Tree Levels Using Object-Oriented Classification of Unmanned Aerial Vehicle (uav) Images

NASA Astrophysics Data System (ADS)

Chenari, A.; Erfanifard, Y.; Dehghani, M.; Pourghasemi, H. R.

2017-09-01

Remotely sensed datasets offer a reliable means to precisely estimate biophysical characteristics of individual species sparsely distributed in open woodlands. Moreover, object-oriented classification has exhibited significant advantages over different classification methods for delineation of tree crowns and recognition of species in various types of ecosystems. However, it still is unclear if this widely-used classification method can have its advantages on unmanned aerial vehicle (UAV) digital images for mapping vegetation cover at single-tree levels. In this study, UAV orthoimagery was classified using object-oriented classification method for mapping a part of wild pistachio nature reserve in Zagros open woodlands, Fars Province, Iran. This research focused on recognizing two main species of the study area (i.e., wild pistachio and wild almond) and estimating their mean crown area. The orthoimage of study area was consisted of 1,076 images with spatial resolution of 3.47 cm which was georeferenced using 12 ground control points (RMSE=8 cm) gathered by real-time kinematic (RTK) method. The results showed that the UAV orthoimagery classified by object-oriented method efficiently estimated mean crown area of wild pistachios (52.09±24.67 m2) and wild almonds (3.97±1.69 m2) with no significant difference with their observed values (α=0.05). In addition, the results showed that wild pistachios (accuracy of 0.90 and precision of 0.92) and wild almonds (accuracy of 0.90 and precision of 0.89) were well recognized by image segmentation. In general, we concluded that UAV orthoimagery can efficiently produce precise biophysical data of vegetation stands at single-tree levels, which therefore is suitable for assessment and monitoring open woodlands.

Carbon transfer from photosynthesis to below ground fine root/hyphae respiration in Quercus serrata using stable carbon isotope pulse labeling

NASA Astrophysics Data System (ADS)

Dannoura, M.; Kominami, Y.; Takanashi, S.; Takahashi, K.

2013-12-01

Studying carbon allocation in trees is a key to better understand belowground carbon cycle and its response to climate change. Tracing 13C in tree and soil compartments after pulse labeling is one of powerful tool to study the fate of carbon in forest ecosystems. This experiment was conducted in Yamashiro experimental forest, Kyoto, Japan. Annual mean temperature and precipitation from 1994 to 2009 are 15.5 ° C and 1,388 mm respectively. The branch pulse labeling were done 7 times in 2011 using same branch of Quercus serrata (H:11.7 m, DBH; 33.7 cm) to see seasonal variations of carbon velocity. Whole crown labeling of Quercus serrata (H:9 m, DBH; 13.7 cm) was done in 2012 to study carbon allocation and to especially focus on belowground carbon flux until to the hyphae respiration. Pure 13CO2 (99.9%) was injected to the labeling chamber which was set to branch or crown. Then, after one hour of branch labeling and 3.5 hour for crown labeling, the chamber was opened. Trunk respiration chambers, fine root chambers and hyphae chambers were set to the target tree to trace labeled carbon in the CO2 efflux. 41 μm mesh was used to exclude ingrowth of roots into hyphae chambers. The results show that the velocity of carbon through the tree varied seasonally, with higher velocity in summer than autumn, averaging 0.47 m h-1. Half-lives of labeled carbon in autotrophic respiration were similar above and below ground during the growing season, but they were twice longer in trunk than in root in autumn. From the whole crown labeling done end of growing season, the 13CO2 signal was observed 25 hours after labeling in trunk chamber and 34-37.7 hours after labeling in fine root and hyphae respiration almost simultaneously. Half-lives of 13 was longer in trunk than below ground. Trunk respiration was still using labelled carbon during winter suggesting that winter trunk respiration is partly fueled by carbon stored in the trunk at the end of the growing season.

Generic biomass functions for Norway spruce in Central Europe--a meta-analysis approach toward prediction and uncertainty estimation.

PubMed

Wirth, Christian; Schumacher, Jens; Schulze, Ernst-Detlef

2004-02-01

To facilitate future carbon and nutrient inventories, we used mixed-effect linear models to develop new generic biomass functions for Norway spruce (Picea abies (L.) Karst.) in Central Europe. We present both the functions and their respective variance-covariance matrices and illustrate their application for biomass prediction and uncertainty estimation for Norway spruce trees ranging widely in size, age, competitive status and site. We collected biomass data for 688 trees sampled in 102 stands by 19 authors. The total number of trees in the "base" model data sets containing the predictor variables diameter at breast height (D), height (H), age (A), site index (SI) and site elevation (HSL) varied according to compartment (roots: n = 114, stem: n = 235, dry branches: n = 207, live branches: n = 429 and needles: n = 551). "Core" data sets with about 40% fewer trees could be extracted containing the additional predictor variables crown length and social class. A set of 43 candidate models representing combinations of lnD, lnH, lnA, SI and HSL, including second-order polynomials and interactions, was established. The categorical variable "author" subsuming mainly methodological differences was included as a random effect in a mixed linear model. The Akaike Information Criterion was used for model selection. The best models for stem, root and branch biomass contained only combinations of D, H and A as predictors. More complex models that included site-related variables resulted for needle biomass. Adding crown length as a predictor for needles, branches and roots reduced both the bias and the confidence interval of predictions substantially. Applying the best models to a test data set of 17 stands ranging in age from 16 to 172 years produced realistic allocation patterns at the tree and stand levels. The 95% confidence intervals (% of mean prediction) were highest for crown compartments (approximately +/- 12%) and lowest for stem biomass (approximately +/- 5%), and within each compartment, they were highest for the youngest and oldest stands, respectively.

Effects of water stress on irradiance acclimation of leaf traits in almond trees.

PubMed

Egea, Gregorio; González-Real, María M; Baille, Alain; Nortes, Pedro A; Conesa, María R; Ruiz-Salleres, Isabel

2012-04-01

Photosynthetic acclimation to highly variable local irradiance within the tree crown plays a primary role in determining tree carbon uptake. This study explores the plasticity of leaf structural and physiological traits in response to the interactive effects of ontogeny, water stress and irradiance in adult almond trees that have been subjected to three water regimes (full irrigation, deficit irrigation and rain-fed) for a 3-year period (2006-08) in a semiarid climate. Leaf structural (dry mass per unit area, N and chlorophyll content) and photosynthetic (maximum net CO(2) assimilation, A(max), maximum stomatal conductance, g(s,max), and mesophyll conductance, g(m)) traits and stem-to-leaf hydraulic conductance (K(s-l)) were determined throughout the 2008 growing season in leaves of outer south-facing (S-leaves) and inner northwest-facing (NW-leaves) shoots. Leaf plasticity was quantified by means of an exposure adjustment coefficient (ε=1-X(NW)/X(S)) for each trait (X) of S- and NW-leaves. Photosynthetic traits and K(s-l) exhibited higher irradiance-elicited plasticity (higher ε) than structural traits in all treatments, with the highest and lowest plasticity being observed in the fully irrigated and rain-fed trees, respectively. Our results suggest that water stress modulates the irradiance-elicited plasticity of almond leaves through changes in crown architecture. Such changes lead to a more even distribution of within-crown irradiance, and hence of the photosynthetic capacity, as water stress intensifies. Ontogeny drove seasonal changes only in the ε of area- and mass-based N content and mass-based chlorophyll content, while no leaf age-dependent effect was observed on ε as regards the physiological traits. Our results also indicate that the irradiance-elicited plasticity of A(max) is mainly driven by changes in leaf dry mass per unit area, in g(m) and, most likely, in the partitioning of the leaf N content.

Comparing Individual Tree Segmentation Based on High Resolution Multispectral Image and Lidar Data

NASA Astrophysics Data System (ADS)

Xiao, P.; Kelly, M.; Guo, Q.

2014-12-01

This study compares the use of high-resolution multispectral WorldView images and high density Lidar data for individual tree segmentation. The application focuses on coniferous and deciduous forests in the Sierra Nevada Mountains. The tree objects are obtained in two ways: a hybrid region-merging segmentation method with multispectral images, and a top-down and bottom-up region-growing method with Lidar data. The hybrid region-merging method is used to segment individual tree from multispectral images. It integrates the advantages of global-oriented and local-oriented region-merging strategies into a unified framework. The globally most-similar pair of regions is used to determine the starting point of a growing region. The merging iterations are constrained within the local vicinity, thus the segmentation is accelerated and can reflect the local context. The top-down region-growing method is adopted in coniferous forest to delineate individual tree from Lidar data. It exploits the spacing between the tops of trees to identify and group points into a single tree based on simple rules of proximity and likely tree shape. The bottom-up region-growing method based on the intensity and 3D structure of Lidar data is applied in deciduous forest. It segments tree trunks based on the intensity and topological relationships of the points, and then allocate other points to exact tree crowns according to distance. The accuracies for each method are evaluated with field survey data in several test sites, covering dense and sparse canopy. Three types of segmentation results are produced: true positive represents a correctly segmented individual tree, false negative represents a tree that is not detected and assigned to a nearby tree, and false positive represents that a point or pixel cluster is segmented as a tree that does not in fact exist. They respectively represent correct-, under-, and over-segmentation. Three types of index are compared for segmenting individual tree from multispectral image and Lidar data: recall, precision and F-score. This work explores the tradeoff between the expensive Lidar data and inexpensive multispectral image. The conclusion will guide the optimal data selection in different density canopy areas for individual tree segmentation, and contribute to the field of forest remote sensing.

Fire and forest history at Mount Rushmore.

PubMed

Brown, Peter M; Wienk, Cody L; Symstad, Amy J

2008-12-01

Mount Rushmore National Memorial in the Black Hills of South Dakota is known worldwide for its massive sculpture of four of the United States' most respected presidents. The Memorial landscape also is covered by extensive ponderosa pine (Pinus ponderosa) forest that has not burned in over a century. We compiled dendroecological and forest structural data from 29 plots across the 517-ha Memorial and used fire behavior modeling to reconstruct the historical fire regime and forest structure and compare them to current conditions. The historical fire regime is best characterized as one of low-severity surface fires with occasional (> 100 years) patches (< 100 ha) of passive crown fire. We estimate that only approximately 3.3% of the landscape burned as crown fire during 22 landscape fire years (recorded at > or = 25% of plots) between 1529 and 1893. The last landscape fire was in 1893. Mean fire intervals before 1893 varied depending on spatial scale, from 34 years based on scar-to-scar intervals on individual trees to 16 years between landscape fire years. Modal fire intervals were 11-15 years and did not vary with scale. Fire rotation (the time to burn an area the size of the study area) was estimated to be 30 years for surface fire and 800+ years for crown fire. The current forest is denser and contains more small trees, fewer large trees, lower canopy base heights, and greater canopy bulk density than a reconstructed historical (1870) forest. Fire behavior modeling using the NEXUS program suggests that surface fires would have dominated fire behavior in the 1870 forest during both moderate and severe weather conditions, while crown fire would dominate in the current forest especially under severe weather. Changes in the fire regime and forest structure at Mount Rushmore parallel those seen in ponderosa pine forests from the southwestern United States. Shifts from historical to current forest structure and the increased likelihood of crown fire justify the need for forest restoration before a catastrophic wildfire occurs and adversely impacts the ecological and aesthetic setting of the Mount Rushmore sculpture.

Forest Health Monitoring in Pennsylvania 1998-1999

Treesearch

Northeastern Research Station

2002-01-01

Pennsylvania has mature forests dominated by hardwood species. Red maple was common in all size classes. Most trees are healthy, with full crowns (low transparency, high density), little dieback, and little damage.

Modeling of contact theories for the manipulation of biological micro/nanoparticles in the form of circular crowned rollers based on the atomic force microscope

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

Korayem, M. H.; Khaksar, H.; Taheri, M.

2013-11-14

This article has dealt with the development and modeling of various contact theories for biological nanoparticles shaped as cylinders and circular crowned rollers for application in the manipulation of different biological micro/nanoparticles based on Atomic Force Microscope. First, the effective contact forces were simulated, and their impact on contact mechanics simulation was investigated. In the next step, the Hertz contact model was simulated and compared for gold and DNA nanoparticles with the three types of spherical, cylindrical, and circular crowned roller type contact geometries. Then by reducing the length of the cylindrical section in the circular crowned roller geometry, themore » geometry of the body was made to approach that of a sphere, and the results were compared for DNA nanoparticles. To anticipatory validate the developed theories, the results of the cylindrical and the circular crowned roller contacts were compared with the results of the existing spherical contact simulations. Following the development of these contact models for the manipulation of various biological micro/nanoparticles, the cylindrical and the circular crowned roller type contact theories were modeled based on the theories of Lundberg, Dowson, Nikpur, Heoprich, and Hertz for the manipulation of biological micro/nanoparticles. Then, for a more accurate validation, the results obtained from the simulations were compared with those obtained by the finite element method and with the experimental results available in previous articles. The previous research works on the simulation of nanomanipulation have mainly investigated the contact theories used in the manipulation of spherical micro/nanoparticles. However since in real biomanipulation situations, biological micro/nanoparticles of more complex shapes need to be displaced in biological environments, this article therefore has modeled and compared, for the first time, different contact theories for use in the biomanipulation of cylindrical and circular crowned roller shaped micro/nanoparticles. The results of models indicate that the contact model of Hertz achieves the largest amount of deformation for the DNA nanoparticle in cylindrical form and the contact model of Heoprich achieves the largest deformation for the circular crowned roller shaped DNA. Of course, this finding is not always true for the other nanoparticles; and considering the mechanical and environmental characteristics, different results can be obtained. Also, by comparing the deformations of different types of nanoparticles, it was determined that the platelet type nanoparticles display the highest degree of deformation in all the considered models, due to their particular mechanical characteristics.« less

Hydraulic constraints modify optimal photosynthetic profiles in giant sequoia trees.

PubMed

Ambrose, Anthony R; Baxter, Wendy L; Wong, Christopher S; Burgess, Stephen S O; Williams, Cameron B; Næsborg, Rikke R; Koch, George W; Dawson, Todd E

2016-11-01

Optimality theory states that whole-tree carbon gain is maximized when leaf N and photosynthetic capacity profiles are distributed along vertical light gradients such that the marginal gain of nitrogen investment is identical among leaves. However, observed photosynthetic N gradients in trees do not follow this prediction, and the causes for this apparent discrepancy remain uncertain. Our objective was to evaluate how hydraulic limitations potentially modify crown-level optimization in Sequoiadendron giganteum (giant sequoia) trees up to 90 m tall. Leaf water potential (Ψ l ) and branch sap flow closely followed diurnal patterns of solar radiation throughout each tree crown. Minimum leaf water potential correlated negatively with height above ground, while leaf mass per area (LMA), shoot mass per area (SMA), leaf nitrogen content (%N), and bulk leaf stable carbon isotope ratios (δ(13)C) correlated positively with height. We found no significant vertical trends in maximum leaf photosynthesis (A), stomatal conductance (g s), and intrinsic water-use efficiency (A/g s), nor in branch-averaged transpiration (E L), stomatal conductance (G S), and hydraulic conductance (K L). Adjustments in hydraulic architecture appear to partially compensate for increasing hydraulic limitations with height in giant sequoia, allowing them to sustain global maximum summer water use rates exceeding 2000 kg day(-1). However, we found that leaf N and photosynthetic capacity do not follow the vertical light gradient, supporting the hypothesis that increasing limitations on water transport capacity with height modify photosynthetic optimization in tall trees.

Estimating Wood Volume for Pinus Brutia Trees in Forest Stands from QUICKBIRD-2 Imagery

NASA Astrophysics Data System (ADS)

Patias, Petros; Stournara, Panagiota

2016-06-01

Knowledge of forest parameters, such as wood volume, is required for a sustainable forest management. Collecting such information in the field is laborious and even not feasible in inaccessible areas. In this study, tree wood volume is estimated utilizing remote sensing techniques, which can facilitate the extraction of relevant information. The study area is the University Forest of Taxiarchis, which is located in central Chalkidiki, Northern Greece and covers an area of 58km2. The tree species under study is the conifer evergreen species P. brutia (Calabrian pine). Three plot surfaces of 10m radius were used. VHR Quickbird-2 images are used in combination with an allometric relationship connecting the Tree Crown with the Diameter at breast height (Dbh), and a volume table developed for Greece. The overall methodology is based on individual tree crown delineation, based on (a) the marker-controlled watershed segmentation approach and (b) the GEographic Object-Based Image Analysis approach. The aim of the first approach is to extract separate segments each of them including a single tree and eventual lower vegetation, shadows, etc. The aim of the second approach is to detect and remove the "noisy" background. In the application of the first approach, the Blue, Green, Red, Infrared and PCA-1 bands are tested separately. In the application of the second approach, NDVI and image brightness thresholds are utilized. The achieved results are evaluated against field plot data. Their observed difference are between -5% to +10%.

A rapid hard-mast index from acorn presence-absence tallies

Treesearch

Cathryn H. Greenberg; Gordon S. Warburton

2007-01-01

We used 21 years of acorn data from visual surveys of oak (Quercus spp.) trees (n ¼ 20,113) conducted in western North Carolina, USA, to develop predictive equations for hard-mast indices (HMIs) based on the proportion of trees bearing acorns (PBA). We calculated PBA using visual estimates of the percentage of oak crown with acorns (PCA), assigning acorn presence if...

Vegetation and soil effects from prescribed, wild, and combined fire events along a ponderosa pine and grassland mosaic

Treesearch

Theresa Jain; Molly Juillerat; Jonathan Sandquist; Mike Ford; Brad Sauer; Robert Mitchell; Scott McAvoy; Justin Hanley; Jon David

2007-01-01

We describe the efficacy of prescribed fires after two wildfires burned through and around these fires located in eastern Montana within the Missouri River Breaks. The objectives of the prescribed fires were to decrease tree density and favor increased herbaceous cover, thus decreasing the potential for crown fire. Our objective was to evaluate post-fire tree density,...

Validating the Malheur model for predicting ponderosa pine post-fire mortality using 24 fires in the Pacific Northwest, USA

Treesearch

Walter G. Thies; Douglas J. Westlind

2012-01-01

Fires, whether intentionally or accidentally set, commonly occur in western interior forests of the US. Following fire, managers need the ability to predict mortality of individual trees based on easily observed characteristics. Previously, a two-factor model using crown scorch and bole scorch proportions was developed with data from 3415 trees for predicting the...

Symptoms and Diagnosis of Annosus Root Disease in the Intermountain Western United States

Treesearch

James W. Byler

1989-01-01

Stand patterns of annosus root disease include various degrees and patterns of tree mortality; tree crown, root collar, and root symptoms; and the condition and location of stumps. In the Intermountain states of Montana, Idaho, and Utah, annosus root disease is found in the ponderosa pine, mixed conifer and high-elevation fir forests. Stand patterns are of value in...

Cold-season patterns of reserve and soluble carbohydrates in sugar maple and ice-damaged trees of two age classes following drought

Treesearch

B. L. Wong; K. L. Baggett; A. H. Rye

2009-01-01

This study examines the effects of summer drought on the composition and profiles of cold-season reserve and soluble carbohydrates in sugar maple (Acer saccharum Marsh.) trees (50-100 years old or ~200 years old) in which the crowns were nondamaged or damaged by the 1998 ice storm. The overall cold season reserve...

Growth after precommercial thinning in two stands of Douglas-fir.

Treesearch

Robert W. Steele

1955-01-01

Twenty years ago, portions of two young Douglas-fir stands on the Wind River Experimental Forest in Skamania County, Washington, were thinned by removing some of the trees in the suppressed and intermediate crown classes. At time of thinning, one stand, (A), was 23 years old and the second, (B), was 30 years old. In both cases site quality is IV. The trees taken out...

Axial and radial water transport and internal water storage in tropical forest canopy trees.

Treesearch

Shelley A. James; Frederick C. Meinzer; Guillermo Goldstein; David Woodruff; Timothy Jones; Teresa Restom; Monica Mejia; Michael Clearwater; Paula Campanello

2003-01-01

Heat and stable isotope tracers were used to study axial and radial water transport in relation to sapwood anatomical characteristics and internal water storage in four canopy tree species of a seasonally dry tropical forest in Panama. Anatomical characteristics of the wood and radial profiles of sap flow were measured at the base, upper trunk, and crown of a single...

Amazon Forest Structure from IKONOS Satellite Data and the Automated Characterization of Forest Canopy Properties

Treesearch

Michael Palace; Michael Keller; Gregory P. Asner; Stephen Hagen; Bobby Braswell

2008-01-01

We developed an automated tree crown analysis algorithm using 1-m panchromatic IKONOS satellite images to examine forest canopy structure in the Brazilian Amazon. The algorithm was calibrated on the landscape level with tree geometry and forest stand data at the Fazenda Cauaxi (3.75◦ S, 48.37◦ W) in the eastern Amazon, and then compared with forest...

Cooperative advanced-generation breeding and testing of coastal Douglas-fir and western hemlock—strategy and implementation.

Treesearch

K. J.S. Jayawickrama; G.R. Johnson; T. Ye

2005-01-01

As in many temperate regions of the world, forest tree improvement got underway in the Pacific Northwest of the USA in the 1950s, with a number of companies and agencies starting independent tree improvement programs. Booth-Kelly Lumber Co., Crown Zellerbach Corp., the Industrial Forestry Association, Port Blakely Mill Co., Simpson Timber Co., Timber Service Co., the...

Diameter growth of individual hardwood trees

Treesearch

G.R., Jr. Trimble; G.R. Trimble

1969-01-01

Between 1959 and 1967 a study of d.b.h. growth rates was made on individual hardwood trees near Parsons, W. Va. From this study, we obtained information that will help foresters to predict growth. We learned that the correlation of the more easily used crown classification with d.b.h. growth is as good as or better than the correlation of vigor classes with d.b.h....

Revised white pine stocking guide for managed stands

Treesearch

William B. Leak; Neil I. Lamson

1999-01-01

Stocking guides are basic tools for forest managers. They provide estimates of the range in acceptable stocking for full occupancy of the site. The first stocking guide for white pine was developed by Philbrook et al (1973). It was of conventional format: showing trees and basal area per acre (in the main crown canopy) by mean stand dbh (the tree of average basal area...

A diameter increment model for Red Fir in California and Southern Oregon

Treesearch

K. Leroy Dolph

1992-01-01

Periodic (10-year) diameter increment of individual red fir trees in Califomia and southern Oregon can be predicted from initial diameter and crown ratio of each tree, site index, percent slope, and aspect of the site. The model actually predicts the natural logarithm ofthe change in squared diameter inside bark between the startand the end of a 10-year growth period....

Diameter Growth of Loblolly Pine Trees as Affected by Soil-Moisture Availibility

Treesearch

John R. Bassett

1964-01-01

In a 30-year-old even-aged stand of loblolly pine on a site 90 loessial soil in southeast Arkansas during foul growing seasons, most trees on plots thinned to 125 square feet of basal area per acre increased in basal area continuously when, under the crown canopy, available water in the surface foot remained above 65 percent. Measurable diameter growth ceased when...

Detecting changes in tree health and productivity in silver fir-beech forests of Slovenia

Treesearch

N. Torelli; W.C. Shortle; K. Cufar; F. Ferlin; K.T. Smith

1999-01-01

Cambial electrical resistance (CER) was used as an objective measure of vitality of silver fir (Abies alba) in the forests of Slovenia. Trees were rated during the growing season by CER and a subjective crown status index (CSI). Both CER and CSI were inversely correlated to annual ring width increment. Using both CER and CSI, fir were assigned to...

A multi-calibrated mitochondrial phylogeny of extant Bovidae (Artiodactyla, Ruminantia) and the importance of the fossil record to systematics.

PubMed

Bibi, Faysal

2013-08-08

Molecular phylogenetics has provided unprecedented resolution in the ruminant evolutionary tree. However, molecular age estimates using only one or a few (often misapplied) fossil calibration points have produced a diversity of conflicting ages for important evolutionary events within this clade. I here identify 16 fossil calibration points of relevance to the phylogeny of Bovidae and Ruminantia and use these, individually and together, to construct a dated molecular phylogeny through a reanalysis of the full mitochondrial genome of over 100 ruminant species. The new multi-calibrated tree provides ages that are younger overall than found in previous studies. Among these are young ages for the origin of crown Ruminantia (39.3-28.8 Ma), and crown Bovidae (17.3-15.1 Ma). These are argued to be reasonable hypotheses given that many basal fossils assigned to these taxa may in fact lie on the stem groups leading to the crown clades, thus inflating previous age estimates. Areas of conflict between molecular and fossil dates do persist, however, especially with regard to the base of the rapid Pecoran radiation and the sister relationship of Moschidae to Bovidae. Results of the single-calibrated analyses also show that a very wide range of molecular age estimates are obtainable using different calibration points, and that the choice of calibration point can influence the topology of the resulting tree. Compared to the single-calibrated trees, the multi-calibrated tree exhibits smaller variance in estimated ages and better reflects the fossil record. The use of a large number of vetted fossil calibration points with soft bounds is promoted as a better approach than using just one or a few calibrations, or relying on internal-congruency metrics to discard good fossil data. This study also highlights the importance of considering morphological and ecological characteristics of clades when delimiting higher taxa. I also illustrate how phylogeographic and paleoenvironmental hypotheses inferred from a tree containing only extant taxa can be problematic without consideration of the fossil record. Incorporating the fossil record of Ruminantia is a necessary step for future analyses aiming to reconstruct the evolutionary history of this clade.

Does initial spacing influence crown and hydraulic architecture of Eucalyptus marginata?

PubMed

Grigg, A H; Macfarlane, C; Evangelista, C; Eamus, D; Adams, M A

2008-05-01

Long-term declines in rainfall in south-western Australia have resulted in increased interest in the hydraulic characteristics of jarrah (Eucalyptus marginata Donn ex Smith) forest established in the region's drinking water catchments on rehabilitated bauxite mining sites. We hypothesized that in jarrah forest established on rehabilitated mine sites: (1) leaf area index (L) is independent of initial tree spacing; and (2) more densely planted trees have less leaf area for the same leaf mass, or the same sapwood area, and have denser sapwood. Initial stand densities ranged from about 600 to 9000 stems ha(-1), and trees were 18 years old at the time of sampling. Leaf area index was unaffected by initial stand density, except in the most sparsely stocked stands where L was 1.2 compared with 2.0-2.5 in stands at other spacings. The ratio of leaf area to sapwood area (A(l):A(s)) was unaffected by tree spacing or tree size and was 0.2 at 1.3 m height and 0.25 at the crown base. There were small increases in sapwood density and decreases in leaf specific area with increased spacing. Tree diameter or basal area was a better predictor of leaf area than sapwood area. At the stand scale, basal area was a good predictor of L (r(2) = 0.98, n = 15) except in the densest stands. We conclude that the hydraulic attributes of this forest type are largely independent of initial tree spacing, thus simplifying parameterization of stand and catchment water balance models.

The impact of fossil data on annelid phylogeny inferred from discrete morphological characters.

PubMed

Parry, Luke A; Edgecombe, Gregory D; Eibye-Jacobsen, Danny; Vinther, Jakob

2016-08-31

As a result of their plastic body plan, the relationships of the annelid worms and even the taxonomic makeup of the phylum have long been contentious. Morphological cladistic analyses have typically recovered a monophyletic Polychaeta, with the simple-bodied forms assigned to an early-diverging clade or grade. This is in stark contrast to molecular trees, in which polychaetes are paraphyletic and include clitellates, echiurans and sipunculans. Cambrian stem group annelid body fossils are complex-bodied polychaetes that possess well-developed parapodia and paired head appendages (palps), suggesting that the root of annelids is misplaced in morphological trees. We present a reinvestigation of the morphology of key fossil taxa and include them in a comprehensive phylogenetic analysis of annelids. Analyses using probabilistic methods and both equal- and implied-weights parsimony recover paraphyletic polychaetes and support the conclusion that echiurans and clitellates are derived polychaetes. Morphological trees including fossils depict two main clades of crown-group annelids that are similar, but not identical, to Errantia and Sedentaria, the fundamental groupings in transcriptomic analyses. Removing fossils yields trees that are often less resolved and/or root the tree in greater conflict with molecular topologies. While there are many topological similarities between the analyses herein and recent phylogenomic hypotheses, differences include the exclusion of Sipuncula from Annelida and the taxa forming the deepest crown-group divergences. © 2016 The Authors.

Assessment of Soil Water Composition in the Northern Taiga Coniferous Forests of Background Territories in the Industrially Developed Region

NASA Astrophysics Data System (ADS)

Lukina, N. V.; Ershov, V. V.; Gorbacheva, T. T.; Orlova, M. A.; Isaeva, L. G.; Teben'kova, D. N.

2018-03-01

The composition of soil water under coniferous forests of Murmansk oblast—an industrially developed region of northern Russia—was investigated. The studied objects were dwarf-shrub-green-moss spruce forests and dwarf-shrub-lichen pine forests on Al-Fe-humus podzols ( Albic Rustic Podzols) that are widespread in the boreal zone. The concentrations and removal of organic carbon performing the most important biogeochemical and pedogenic functions were estimated. The results proved significant intra- and inter-biogeocenotic variability in the composition of atmospheric depositions and soil water. Carbon removal with soil water from organic and mineral horizons within elementary biogeoareas (EBGA) under tree crowns was 2-5 and 2-3 times (in some cases, up to 10 times) greater than that in the intercrown areas, respectively. The lowest critical level of mineral nitrogen (0.2 mg/L) was, as a rule, exceeded in tree EBGAs contrary to intercrown areas. Concentrations of sulfates and heavy metals in water of tree EBGA were 3-5 times greater than those in inter-crown areas. Significant inter-biogeocenotic variations related to differences in the height of trees and tree stand density were found. It is argued that adequate characterization of biochemical cycles and assessment of critical levels of components in soil water of forest ecosystems should be performed with due account for the intra- and inter-biogeocenotic variability.