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Height-diameter relationships of tropical Atlantic moist forest trees in southeastern Brazil
Scaranello, Marcos Augusto da Silva;Alves, Luciana Ferreira;Vieira, Simone Aparecida;Camargo, Plinio Barbosa de;Joly, Carlos Alfredo;Martinelli, Luiz Ant?nio;
Scientia Agricola , 2012, DOI: 10.1590/S0103-90162012000100005
Abstract: site-specific height-diameter models may be used to improve biomass estimates for forest inventories where only diameter at breast height (dbh) measurements are available. in this study, we fit height-diameter models for vegetation types of a tropical atlantic forest using field measurements of height across plots along an altitudinal gradient. to fit height-diameter models, we sampled trees by dbh class and measured tree height within 13 one-hectare permanent plots established at four altitude classes. to select the best model we tested the performance of 11 height-diameter models using the akaike information criterion (aic). the weibull and chapman-richards height-diameter models performed better than other models, and regional site-specific models performed better than the general model. in addition, there is a slight variation of height-diameter relationships across the altitudinal gradient and an extensive difference in the stature between the atlantic and amazon forests. the results showed the effect of altitude on tree height estimates and emphasize the need for altitude-specific models that produce more accurate results than a general model that encompasses all altitudes. to improve biomass estimation, the development of regional height-diameter models that estimate tree height using a subset of randomly sampled trees presents an approach to supplement surveys where only diameter has been measured.
The Allometry of Coarse Root Biomass: Log-Transformed Linear Regression or Nonlinear Regression?  [PDF]
Jiangshan Lai, Bo Yang, Dunmei Lin, Andrew J. Kerkhoff, Keping Ma
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0077007
Abstract: Precise estimation of root biomass is important for understanding carbon stocks and dynamics in forests. Traditionally, biomass estimates are based on allometric scaling relationships between stem diameter and coarse root biomass calculated using linear regression (LR) on log-transformed data. Recently, it has been suggested that nonlinear regression (NLR) is a preferable fitting method for scaling relationships. But while this claim has been contested on both theoretical and empirical grounds, and statistical methods have been developed to aid in choosing between the two methods in particular cases, few studies have examined the ramifications of erroneously applying NLR. Here, we use direct measurements of 159 trees belonging to three locally dominant species in east China to compare the LR and NLR models of diameter-root biomass allometry. We then contrast model predictions by estimating stand coarse root biomass based on census data from the nearby 24-ha Gutianshan forest plot and by testing the ability of the models to predict known root biomass values measured on multiple tropical species at the Pasoh Forest Reserve in Malaysia. Based on likelihood estimates for model error distributions, as well as the accuracy of extrapolative predictions, we find that LR on log-transformed data is superior to NLR for fitting diameter-root biomass scaling models. More importantly, inappropriately using NLR leads to grossly inaccurate stand biomass estimates, especially for stands dominated by smaller trees.
The distribution of height and diameter in random non-plane binary trees  [PDF]
Nicolas Broutin,Philippe Flajolet
Mathematics , 2010, DOI: 10.1002/rsa.20393
Abstract: This study is dedicated to precise distributional analyses of the height of non-plane unlabelled binary trees ("Otter trees"), when trees of a given size are taken with equal likelihood. The height of a rooted tree of size $n$ is proved to admit a limiting theta distribution, both in a central and local sense, as well as obey moderate as well as large deviations estimates. The approximations obtained for height also yield the limiting distribution of the diameter of unrooted trees. The proofs rely on a precise analysis, in the complex plane and near singularities, of generating functions associated with trees of bounded height.
Modelling height-diameter relationship for Chir pine trees  [PDF]
RP Sharma
Banko Janakari , 2009, DOI: 10.3126/banko.v19i2.2978
Abstract: Tree height-diameter relationship can be used as an important input component in growth and yield models, and description of stand dynamics. This study aims at establishing robust height-diameter models for Chir pine ( Pinus roxburghii ) trees using regression techniques. Among the twelve non-linear models fitted to height-diameter data from twentythree Chir pine stands in Parbat and Shyangja districts, Hossfeld's model accounted for the largest proportion of height variations (R 2 adj = 86%), and appeared to be biologically most realistic. This model can be applied to similar stand conditions from where study data were procured. Keywords : Chir pine; height-diameter models; model evaluation; stand attributes DOI: 10.3126/banko.v19i2.2978 Banko Janakari , Vol. 19, No.2 2009 pp.3-9 ?
Allometry of a neotropical palm, Euterpe edulis Mart.
Alves, Luciana F.;Martins, Fernando R.;Santos, Flavio A.M.;
Acta Botanica Brasilica , 2004, DOI: 10.1590/S0102-33062004000200016
Abstract: the stem allometry (stem diameter vs. tree height) of a neotropical palm (euterpe edulis) found in rain and seasonal forest of southeastern brazil was examined. observed height-diameter relationships along the stem (diameter at ground level, (dgl), and diameter at breast height (dbh) were compared to three theoretical stability mechanical models: elastic similarity, stress similarity and geometric similarity. slopes of log-transformed height-diameter relationships did not lie near those predicted by any stability mechanical models. significant differences in stem allometry were found when comparing dgl to dbh, suggesting greater increase in dbh with height. the relationship between stability safety factor (ssf) and palm height showed that both dgl and dbh were found to be above mcmahon's theoretical buckling limit for dicotyledonous trees, but some individuals approached this limit in relation to dbh. despite displaying a similar decreasing pattern of ssf with height, differences found in ssf along the stem - greater ssf for dgl when compared to dbh - indicate that the risk of mechanism failure in palms depends upon the size and varies along the stem. distinct allometric relationships along the stem obtained for euterpe edulis may be reflecting possible differences in stem design and growth strategies.
Allometry and growth of eight tree taxa in United Kingdom woodlands  [PDF]
Matthew R. Evans,Aristides Moustakas,Gregory Carey,Yadvinder Malhi,Nathalie Butt,Sue Benham,Denise Pallett,Stefanie Schaefer
Quantitative Biology , 2015,
Abstract: Allometry and growth rates of 8 forest species in the UK. The data were collected from two United Kingdom woodlands - Wytham Woods and Alice Holt. Here we present data from 582 individual trees of eight taxa in the form of summary variables. In addition the raw data files containing the variables from which the summary data were obtained. Large sample sizes with longitudinal data spanning 22 years make these datasets useful for future studies concerned with the way trees change in size and shape over their life-span. The allometric relationships include (1) trunk diameter, (2) height, (3) crown height, (4) crown radius and (5) trunk radial growth rate to (A) the light environment of each tree and (B) diameter at breast height.
Modelling height-diameter relationship for Pinus wallichiana trees for Lete and Kunjo of Mustang district  [PDF]
B. H. Wagle,R. P. Sharma
Banko Janakari , 2011, DOI: 10.3126/banko.v21i2.9125
Abstract: Quantifi cation of height-diameter relationship helps in better understanding of stand dynamics. Height-diameter models can be used as necessary inputs to growth and yield models and growth simulation systems. The researchers developed height-diameter models with 364 Blue pine (Pinus wallichiana) tree data from Lete and Kunjo Village Development Committees (VDCs) of Mustang district. Eighteen non-linear models were calibrated, among which, Weibull model described the largest proportion of height variation (R2 adj = 0. 9362). Gunary and Chapman-Richards’ models also appeared almost identical to Weibull model in terms of fi t statistics and graphical appearance. The researchers recommend Weibull model for predicting total heights of Blue pine trees for the VDCs covered by the study.
The Importance of Large-Diameter Trees to Forest Structural Heterogeneity  [PDF]
James A. Lutz, Andrew J. Larson, James A. Freund, Mark E. Swanson, Kenneth J. Bible
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0082784
Abstract: Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. However, their attendant contributions to forest heterogeneity are rarely addressed. We established the Wind River Forest Dynamics Plot, a 25.6 ha permanent plot within which we tagged and mapped all 30,973 woody stems ≥1 cm dbh, all 1,966 snags ≥10 cm dbh, and all shrub patches ≥2 m2. Basal area of the 26 woody species was 62.18 m2/ha, of which 61.60 m2/ha was trees and 0.58 m2/ha was tall shrubs. Large-diameter trees (≥100 cm dbh) comprised 1.5% of stems, 31.8% of basal area, and 17.6% of the heterogeneity of basal area, with basal area dominated by Tsuga heterophylla and Pseudotsuga menziesii. Small-diameter subpopulations of Pseudotsuga menziesii, Tsuga heterophylla and Thuja plicata, as well as all tree species combined, exhibited significant aggregation relative to the null model of complete spatial randomness (CSR) up to 9 m (P≤0.001). Patterns of large-diameter trees were either not different from CSR (Tsuga heterophylla), or exhibited slight aggregation (Pseudotsuga menziesii and Thuja plicata). Significant spatial repulsion between large-diameter and small-diameter Tsuga heterophylla suggests that large-diameter Tsuga heterophylla function as organizers of tree demography over decadal timescales through competitive interactions. Comparison among two forest dynamics plots suggests that forest structural diversity responds to intermediate-scale environmental heterogeneity and disturbances, similar to hypotheses about patterns of species richness, and richness- ecosystem function. Large mapped plots with detailed within-plot environmental spatial covariates will be required to test these hypotheses.
Ecological Importance of Large-Diameter Trees in a Temperate Mixed-Conifer Forest  [PDF]
James A. Lutz, Andrew J. Larson, Mark E. Swanson, James A. Freund
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0036131
Abstract: Large-diameter trees dominate the structure, dynamics and function of many temperate and tropical forests. Although both scaling theory and competition theory make predictions about the relative composition and spatial patterns of large-diameter trees compared to smaller diameter trees, these predictions are rarely tested. We established a 25.6 ha permanent plot within which we tagged and mapped all trees ≥1 cm dbh, all snags ≥10 cm dbh, and all shrub patches ≥2 m2. We sampled downed woody debris, litter, and duff with line intercept transects. Aboveground live biomass of the 23 woody species was 507.9 Mg/ha, of which 503.8 Mg/ha was trees (SD = 114.3 Mg/ha) and 4.1 Mg/ha was shrubs. Aboveground live and dead biomass was 652.0 Mg/ha. Large-diameter trees comprised 1.4% of individuals but 49.4% of biomass, with biomass dominated by Abies concolor and Pinus lambertiana (93.0% of tree biomass). The large-diameter component dominated the biomass of snags (59.5%) and contributed significantly to that of woody debris (36.6%). Traditional scaling theory was not a good model for either the relationship between tree radii and tree abundance or tree biomass. Spatial patterning of large-diameter trees of the three most abundant species differed from that of small-diameter conspecifics. For A. concolor and P. lambertiana, as well as all trees pooled, large-diameter and small-diameter trees were spatially segregated through inter-tree distances <10 m. Competition alone was insufficient to explain the spatial patterns of large-diameter trees and spatial relationships between large-diameter and small-diameter trees. Long-term observations may reveal regulation of forest biomass and spatial structure by fire, wind, pathogens, and insects in Sierra Nevada mixed-conifer forests. Sustaining ecosystem functions such as carbon storage or provision of specialist species habitat will likely require different management strategies when the functions are performed primarily by a few large trees as opposed to many smaller trees.
Tree height integrated into pan-tropical forest biomass estimates  [PDF]
T. R. Feldpausch,J. Lloyd,S. L. Lewis,R. J. W. Brienen
Biogeosciences Discussions , 2012, DOI: 10.5194/bgd-9-2567-2012
Abstract: Above-ground tropical tree biomass and carbon storage estimates commonly ignore tree height. We estimate the effect of incorporating height (H) on forest biomass estimates using 37 625 concomitant H and diameter measurements (n = 327 plots) and 1816 harvested trees (n = 21 plots) tropics-wide to answer the following questions: 1. For trees of known biomass (from destructive harvests) which H-model form and geographic scale (plot, region, and continent) most reduces biomass estimate uncertainty? 2. How much does including H relationship estimates derived in (1) reduce uncertainty in biomass estimates across 327 plots spanning four continents? 3. What effect does the inclusion of H in biomass estimates have on plot- and continental-scale forest biomass estimates? The mean relative error in biomass estimates of the destructively harvested trees was half (mean 0.06) when including H, compared to excluding H (mean 0.13). The power- and Weibull-H asymptotic model provided the greatest reduction in uncertainty, with the regional Weibull-H model preferred because it reduces uncertainty in smaller-diameter classes that contain the bulk of biomass per hectare in most forests. Propagating the relationships from destructively harvested tree biomass to each of the 327 plots from across the tropics shows errors are reduced from 41.8 Mg ha 1 (range 6.6 to 112.4) to 8.0 Mg ha 1 ( 2.5 to 23.0) when including $H$. For all plots, above-ground live biomass was 52.2±17.3 Mg ha 1 lower when including H estimates (13%), with the greatest reductions in estimated biomass in Brazilian Shield forests and relatively no change in the Guyana Shield, central Africa and southeast Asia. We show fundamentally different stand structure across the four forested tropical continents, which affects biomass reductions due to $H$. African forests store a greater portion of total biomass in large-diameter trees and trees are on average larger in diameter. This contrasts to forests on all other continents where smaller-diameter trees contain the greatest fractions of total biomass. After accounting for variation in $H$, total biomass per hectare is greatest in Australia, the Guyana Shield, and Asia and lowest in W. Africa, W. Amazonia, and the Brazilian Shield (descending order). Thus, if closed canopy tropical forests span 1668 million km2 and store 285 Pg C, then the overestimate is 35 Pg C if H is ignored, and the sampled plots are an unbiased statistical representation of all tropical forest in terms of biomass and height factors. Our results show that tree $H$ is an important allometric fac
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