scholarly journals Effects of Stand Age on Biomass Allocation and Allometry of Quercus Acutissima in the Central Loess Plateau of China

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 41 ◽  
Author(s):  
Bin Yang ◽  
Wenyan Xue ◽  
Shichuan Yu ◽  
Jianyun Zhou ◽  
Wenhui Zhang

We studied the effects of stand age on allocation and equation fitting of aboveground and below-ground biomass in four Quercus acutissima stands (14, 31, 46, and 63 years old) in the Central Loess Plateau of China. The stem wood, stem bark, branch, foliage, and belowground biomass of each of the 20 destructive harvesting trees were quantified. The mean total biomass of each tree was 28.8, 106.8, 380.6, and 603.4 kg/tree in the 14-, 31-, 46-, and 63-year-old stands, respectively. Aboveground biomass accounted for 72.25%, 73.05%, 76.14%, and 80.37% of the total tree biomass in the 14-, 31-, 46-, and 63-year-old stands, respectively, and stem wood was the major component of tree biomass. The proportion of stem (with bark) biomass to total tree biomass increased with stand age while the proportions of branch, foliage, and belowground biomass to total tree biomass decreased with stand age. The ratio of belowground biomass to aboveground biomass decreased from 0.39 in the 14-year-old stand to 0.37, 0.31, and 0.24 in the 31-, 46-, and 63-year-old stands, respectively. Age-specific biomass equations in each stand were developed for stem wood, stem bark, aboveground, and total tree. The inclusion of tree height as a second variable improved the total tree biomass equation fitting for middle-aged (31-year-old and 46-year-old) stands but not young (14 years old) and mature (63 years old) stands. Moreover, biomass conversion and expansion factors (BCEFs) varied with stand age, showing a decreasing trend with increasing stand age. These results indicate that stand age alters the biomass allocation of Q. acutissima and results in age-specific allometric biomass equations and BCEFs. Therefore, to obtain accurate estimates of Q. acutissima forest biomass and carbon stocks, age-specific changes need to be considered.

2019 ◽  
Vol 65 (3-4) ◽  
pp. 166-179 ◽  
Author(s):  
Vladimir A. Usoltsev ◽  
Katarína Merganičová ◽  
Bohdan Konôpka ◽  
Anna A. Osmirko ◽  
Ivan S. Tsepordey ◽  
...  

Abstract Climate change, especially modified courses of temperature and precipitation, has a significant impact on forest functioning and productivity. Moreover, some alterations in tree biomass allocation (e.g. root to shoot ratio, foliage to wood parts) might be expected in these changing ecological conditions. Therefore, we attempted to model fir stand biomass (t ha−1) along the trans-Eurasian hydrothermal gradients using the data from 272 forest stands. The model outputs suggested that all biomass components, except for the crown mass, change in a common pattern, but in different ratios. Specifically, in the range of mean January temperature and precipitation of −30°C to +10°C and 300 to 900 mm, fir stand biomass increases with both increasing temperature and precipitation. Under an assumed increase of January temperature by 1°C, biomass of roots and of all components of the aboveground biomass of fir stands increased (under the assumption that the precipitation level did not change). Similarly, an assumed increase in precipitation by 100 mm resulted in the increased biomass of roots and of all aboveground components. We conclude that fir seems to be a perspective taxon from the point of its productive properties in the ongoing process of climate change.


2007 ◽  
Vol 37 (5) ◽  
pp. 895-906 ◽  
Author(s):  
Nuno António ◽  
Margarida Tomé ◽  
José Tomé ◽  
Paula Soares ◽  
Luís Fontes

The objective of this study was to develop a system of compatible equations to estimate eucalyptus ( Eucalyptus globulus Labill.) tree aboveground biomass and biomass of tree components for forest biomass prediction across regional boundaries. Data came from 441 trees sampled on several sites (99 and 14 plots in planted and coppice regenerated stands, respectively) representative of the eucalyptus expansion area in Portugal. The system of equations, simultaneously fitted using seemingly unrelated regression, was based on the allometric model for the biomass of stem wood, stem bark, leaves, and branches. Total aboveground biomass was expressed as the sum of the biomass of the respective tree components. The study allowed the following conclusions: (i) there is a significant increase in the predictive ability of the models that include height (stem components) or crown length (crown components) as an additional predictor to diameter at 1.30 m; (ii) there is a clear effect of the stage of development of the stand on tree allometry, with a decreasing pattern of the allometric constants; (iii) no effect of stand density, site index or climate on tree allometry was found; and (iv) for practical purposes, the same system of equations can be used for planted and coppice regenerated stands.


Author(s):  
Radek Pokorný ◽  
Petra Rajsnerová ◽  
Jiří Kubásek ◽  
Irena Marková ◽  
Ivana Tomášková

Aboveground biomass, allometric relationships and early to late wood proportions were investigated in two even-aged monocultures of Norway spruce (Picea abies [L.] Karst) located at mountain and highland localities of the Czech Republic. However similar stand age and tree size, mountain trees comparing to them from highland showed less/tapering stems, lower aboveground biomass and lower stem wood density along the whole stem vertical profile as a result of different early to late wood proportion. These proportions were 79 % and 54 % for early wood, and 21 % and 46 % for late wood within mean stem annual circle in mountain and highland locality, respectively. These different proportions seem to reflected site specific growing conditions, particularly highly sufficient water availability during spring time in mountain region- support early wood growth, whereas elevated air temperature during summer time in highland region stimulate late wood growth.


2011 ◽  
Vol 57 (No. 1) ◽  
pp. 8-15 ◽  
Author(s):  
J. Novák ◽  
M. Slodičák ◽  
D. Dušek

This study is focused on substitute European larch stands in the Kru&scaron;n&eacute; hory Mts. (northern part of the Czech Republic). Research was conducted within larch thinning experiment Kalek (780 m a.s.l. in the category Piceeto-Fagetum oligo-mesotrophicum &ndash; Calamagrostis villosa). Results showed that the aboveground biomass of the investigated substitute unthinned larch stand represented approximately 102 thousand kg of dry matter per ha at the age of 20 years. Stemwood (ca 59%) is the most important part of the aboveground biomass. Needles, live and dead branches accounted approximately for 6%, 17% and 11%, respectively, and stem bark only for 7%. At the age of<br />20 years, the investigated substitute unthinned larch stand accumulated: nitrogen &ndash; 307 kg, phosphorus &ndash; 21 kg, potassium &ndash; 136 kg, calcium &ndash; 122 kg, magnesium &ndash; 53 kg per hectare. Thinning with consequent removal of aboveground biomass may result in nutrient losses. Especially, the removal of whole tree biomass by thinning for chipping in areas previously degraded by acid deposition may result in calcium and magnesium deficiency because of their low content in forest soil. On the other hand, thinning supported faster growth of trees left after thinning and consequently faster biomass and nutrient accumulation. Our results supported the recommendation that the use of biomass from thinning for chipping should be limited to stemwood only and the remaining aboveground biomass (mainly needles and branches) should be left in the forest ecosystem for decomposition in conditions of the historically disturbed area of the Kru&scaron;n&eacute; hory Mts.


1981 ◽  
Vol 11 (1) ◽  
pp. 13-17 ◽  
Author(s):  
M. F. Ker ◽  
G. D. Van Raalte

Equations are given, based on data from 298 balsam fir and 88 white spruce trees in northwestern New Brunswick, for predicting ovendry weight of biomass for balsam fir and white spruce trees. Separate equations are given for each of nine components: stem wood, stem bark, total stem, branches, foliage, total crown, total aboveground weight, roots, and total tree. Independent variables used in the equations include diameter at breast height (dbh), height, crown width, crown length, and indices of basal area, crown area, and crown volume.


2019 ◽  
Vol 49 (1) ◽  
pp. 27-40 ◽  
Author(s):  
Dehai Zhao ◽  
James Westfall ◽  
John W. Coulston ◽  
Thomas B. Lynch ◽  
Bronson P. Bullock ◽  
...  

Both aggregative and disaggregative strategies were used to develop additive nonlinear biomass equations for slash pine (Pinus elliottii Engelm. var. elliottii) trees in the southeastern United States. In the aggregative approach, the total tree biomass equation was specified by aggregating the expectations of component biomass models, and their parameters were estimated by jointly fitting all component and total biomass equations using weighted nonlinear seemingly unrelated regression (NSUR) (SUR1) or by jointly fitting component biomass equations using weighted NSUR (SUR2). In an alternative disaggregative approach (DRM), the biomass component proportions were modeled using Dirichlet regression, and the estimated total tree biomass was disaggregated into biomass components based on their estimated proportions. There was no single system to predict biomass that was best for all components and total tree biomass. The ranking of the three systems based on an array of fit statistics followed the order of SUR2 > SUR1 > DRM. All three systems provided more accurate biomass predictions than previously published equations.


2005 ◽  
Vol 35 (8) ◽  
pp. 1996-2018 ◽  
Author(s):  
M-C Lambert ◽  
C-H Ung ◽  
F Raulier

The estimation of aboveground biomass density (organic dry mass per unit area) is required for balancing Canadian national forest carbon budgets. Tree biomass equations are the basic tool for converting inventory plot data into biomass density. New sets of national tree biomass equations have therefore been produced from archival biomass data collected at the beginning of the 1980s through the ENergy from the FORest research program (ENFOR) of the Canadian Forest Service. Since the sampling plan was not standardized among provinces and territories, data had to be harmonized before any biomass equation could be considered at the national level. Two features characterize the new equations: estimated biomass of the compartments (foliage, branch, wood, and bark) are constrained to equal the total biomass, and dependence among error terms for the considered compartments of the same tree is taken into account in the estimates of both the model parameters and the variance prediction. The estimation method known to economists as “seemingly unrelated regression” allowed the inclusion of dependencies among the error terms of the considered biomass compartments. Sets of equations based on diameter at breast height (dbh) and on dbh and height have been produced for 33 species, groups of hardwood and softwood, and for all species combined. Biomass predicted by the new equations was compared with that estimated from provincial equations to evaluate the loss of accuracy when scaling up from the regional to the national scale. Bias and error of prediction from the set of national equations based on dbh and height were generally more similar to those from provincial equations than to those of predictions from the set of equations based on dbh alone.


2002 ◽  
Vol 32 (8) ◽  
pp. 1441-1450 ◽  
Author(s):  
B Bond-Lamberty ◽  
C Wang ◽  
S T Gower

Allometric equations were developed relating aboveground biomass, coarse root biomass, and sapwood area to stem diameter at 17 study sites located in the boreal forests near Thompson, Man. The six species studied were trembling aspen (Populus tremuloides Michx.), paper birch (Betula papyrifera Marsh.), black spruce (Picea mariana (Mill.) BSP), jack pine (Pinus banksiana Lamb.), tamarack (Larix laricina (Du Roi) Koch.), and willow (Salix spp.). Stands ranged in age from 4 to 130 years and were categorized as well or poorly drained. Stem diameter ranged from 0.1 to 23.7 cm. Stem diameter was measured at both the soil surface (D0) and breast height (DBH). The relationship between biomass and diameter, fitted on a log–log scale, changed significantly at ~3 cm DBH, suggesting that allometry differed between saplings and older trees. To eliminate this nonlinearity, a model of form log10 Y = a + b(log10 D) + c(AGE) + d(log10 D × AGE) was used, where D is stem diameter, AGE is stand age, and the cross product is the interaction between diameter and age. Most aboveground biomass equations (N = 326) exhibited excellent fits (R2 > 0.95). Coarse root biomass equations (N = 205) exhibited good fits (R2 > 0.90). Both D0 and DBH were excellent (R2 > 0.95) sapwood area predictors (N = 413). Faster growing species had significantly higher ratios of sapwood area to stem area than did slower growing species. Nonlinear aspects of some of the pooled biomass equations serve as a caution against extrapolating allometric equations beyond the original sample diameter range.


2017 ◽  
Vol 47 (4) ◽  
pp. 467-475 ◽  
Author(s):  
WeiSheng Zeng ◽  
LianJin Zhang ◽  
XinYun Chen ◽  
ZhiChu Cheng ◽  
KeXi Ma ◽  
...  

Current biomass models for Chinese pine (Pinus tabulaeformis Carr.) fail to accurately estimate biomass in large geographic regions because they were usually based on limited sample trees on local sites, incompatible with stem volume, and not additive among components and total biomass. This study was based on mensuration data of individual-tree biomass from large samples of Chinese pine. The purpose was to construct compatible and additive biomass models using the nonlinear error-in-variable simultaneous equations and dummy variable modeling approach. This approach could ensure compatibility of an aboveground biomass model with a biomass conversion factor (BCF) and a stem volume model and compatibility of a belowground biomass model with a root-to-shoot ratio (RSR) model. Also, stem, branch, and foliage biomass models were additive to the aboveground biomass model. Results showed that mean prediction errors (MPEs) of the developed one- and two-variable aboveground biomass models were less than 4% and MPEs of the three-component (stem, branch, and foliage) and belowground biomass models were less than 10%. Furthermore, the effects of main climate variables on above- and below-ground biomass were analyzed. Aboveground biomass was related to mean annual temperature (MAT), while belowground biomass had no significant relationship with either MAT or mean annual precipitation (MAP). The developed models provide a good basis for estimating biomass of Chinese pine forests.


2017 ◽  
Vol 47 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Björn Elfving ◽  
Kristina Ahnlund Ulvcrona ◽  
Gustaf Egnell

Biomass equations for cultivated lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.) were developed based on data from destructive biomass sampling of 164 trees collected from 13 sites at latitudes 61.9°N–66.2°N in northern Sweden. Stand age varied between 20 and 87 years and top height varied between 8 and 32 m. Seeded and planted stands with different densities were included. Allometric biomass equations for all above-stump components were constructed, expressing dry mass of stem, bark, living and dead branch wood, foliage, and cones, as well as total mass. Equations with one to three independent variables were constructed for each component, accounting for variances within and between sites. Estimated values for trees of different sizes were compared with corresponding estimates for lodgepole pine in Canada and Scots pine (Pinus sylvestris L.) in Sweden and Finland. Residual variation of our equations was lower than that of equations from other sources. Our equations predicted average biomass levels similar to the predictions from Canadian equations for natural stands. In comparison with Scots pine, at given stem dimensions, lodgepole pine had 50%–100% more foliage biomass and greater dead branch biomass with increasing tree size. The wide amplitude of our data and the flexible form of our equations should make them useful for wider application.


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