Foliage Biomass Research Articles

Effect of Bacterial Inoculants on Agronomic Performance of Three Genotypes of Potato (<i>Solanum tuberosum</i> L.) in Coastal Areas of Peru

To study the effect of interaction of plant genotypes and populations of microorganisms in the rhizosphere may be an important factor to assess the effectiveness of PGPRs on crop production. The objective of this research was to determine the effect of inoculation of four bacterial strains on the agronomic performance of three commercial cultivars of potato in the province of Canete, Peru. A randomized complete blocks design with three replications on a split plot arrangement was used, in which potato genotypes (three commercial varieties) were assigned to complete plots and inoculation treatments (bacterial strains and control) were allocated to sub-plots, then evaluating the effect for growth promotion related to bacterial strains: Bacillus amyloliquefaciens, B. simplex, Azotobacter sp. and Pantoea sp. on potato agronomic characteristics. As result of inoculation with bacterial strains in potato cultivars Canchan, Perricholi and Unica, significant differences were showed (p<0.05) for vegetative vigor, percentage of inflorescences per plant, foliage weight per plant and weight of the total biomass per hectare with use of inoculation of some of these strains, having a stimulatory effect on development in these commercial varieties, highlighting strain AZO16 M2 (Azotobacter sp.) to promote increased weight of foliage and total biomass and flowering in cv. Perricholi and strain Bac15MB (Bacillus amyloliquefaciens) to regulate the degree of senescence of foliage, specifically in cv. Canchan. Concluding that inoculation with bacterial strains in potato cultivars Canchan, Perricholi and Unica influenced some important crop agronomic characters, although its specific effect was dependent on each potato variety.

Impact of tropospheric ozone on terrestrial biodiversity: A literature analysis to identify ozone sensitive taxa

Tropospheric ozone has long been known as highly phytotoxic. However, currently hardly anything is known whether this air pollutant can also pose a threat to the overall biodiversity in terrestrial ecosystems. Identifying the relative ozone sensitivities of relevant taxa or species can be a first step in an assessment if biodiversity is at risk from ozone. A literature survey was conducted describing experimental and observational results of exposure of organisms and particularly plant species to ozone at environmentally relevant concentrations. For plants ozone effects considered were vegetative growth (e.g. biomass of shoots, foliage, single leaves, stems, and roots), reproduction (number and biomass of seeds and flowers), species development, and symptoms of visible foliar injury. A total of 474 literature references were evaluated which described such effects. For crop plants 54 species with 350 varieties could be considered, while (semi)natural vegetation was represented by 465 vascular plant species comprising 298 herbaceous and 165 woody plant species. Overall, these ozone studies cover only a small fraction of the entire global flora. About two third of woody and about one half of native herbaceous plant species investigated so far have been described as ozone sensitive in at least one study. Ozone sensitivity is slightly higher with respect to visible leaf injury as compared to growth effects, and herbs and deciduous tree species are more responsive than grasses and coniferous trees. Observational results from field surveys conducted along ozone gradients to assess ecosystem effects of ozone in North America and Europe revealed visible macroscopic leaf injuries for 258 herbaceous species. However, these findings often have not been verified under experimental ozone exposure. Albeit the numbers of ozone studies related to a particular plant family varied considerably, high proportions of ozone sensitive species were found e.g. for the families Myrtaceae, Salicaceae and Onograceae, while low proportions of ozone sensitive species were found e.g. for the families Brassicaceae, Boraginaceae and Plantaginaceae. Intra-specific variations of ozone sensitivity of vascular plants were primarily detected in crop species (e.g. wheat, soybean, snap bean, clover, rice), most often derived from screening studies of cultivars for their relative ozone sensitivity/tolerance to ozone. In some cases intra-specific variation of ozone sensitivity is also true for different populations of woody and herbaceous plant species, which often resulted from temporal or spatial differentiation of the relative ozone susceptibility. Therefore, there is some evidence that ozone pollution in the past has already affected plant selection and modified the genetic pool of ozone sensitive genotypes. Information on direct ozone effects on species other than vascular plants (e.g. ferns, mosses, fungi, algae, vertebrates) is very poor or irrelevant, i.e. ozone sensitivities for these taxa could not be described. This is also true for organisms like microbes, arthropods or insects which have not been tested so far for their responses to direct ambient ozone exposure. However, these organisms may be indirectly impaired by ozone via loss of vitality of the plant system to which they are associated.

Biomass equations for lodgepole pine in northern Sweden

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.

Optical sensors for variable rate nitrogen application in dairy pastures

Reducing the amount of nitrogen (N) fertiliser applied to dairy pastures down to agronomically optimised levels would have positive economic and environmental results. The ability of commercially available optical sensors to estimate biomass yield and foliar-N uptake in pastures was investigated. Vegetative indices (Simple Ratio, SR; Water Index, WI; and Normalised Difference Vegetation Index, NDVI) from two active optical reflectance sensors (N-Sensor, Yara; and Greenseeker, Trimble) were compared with manually measured biomass and N-uptake in above-ground foliage. There were three measurements over time, from pastures that had received different N fertiliser applications rates (0, 10, 20, 40 and 80 kg N/ha). It was found that the sensors were able to detect differences in biomass and foliar N-uptake following defoliation of grazed pastures. The tested optical sensors have the potential to inform a real-time variable rate fertiliser application system. Keywords: pasture, nitrogen, optical sensors

THE YIELD OF LETTUCE BREEDING LINE UNDER LED LAMPS IN WINTER GREENHOUSE IN THE NORTH

The lettuce (Lactuca sativa L.) is widely known and favorite vegetable crop among people. In Europe the main production of lettuce is performed on protected ground with application of artificial light sources. The artificially-lighted culture of salad became very actually acquired in the north. Previously, on the basis of multi-year studies on yield registration and experiments with different regimes of lighting we have defined the appropriate parameters of supplementary lighting for lettuce with sodium high-pressure lamps that provided the production in different seasons per year. The aim was to study the accumulation of biomass and yield quality in lettuce ‘Aphytsion’ being grown in winter rotation under light-emitting diodes lamps. The accumulation of biomass and yield quality was studied in ‘Aphytsion’, grown in winter rotation under lightemitting diodes lamps ECOLED-BIO-112-185WD120 UniversaLED (ООО ‘GK’ ‘CET’), Perm, in industrial greenhouse OOO ‘Prigorodniy’ at Syktyvkar city. The commodity output was obtained for two cycle of cultivation, November-December and December-January. Yield of foliage biomass was 2.4 kg/m 2 with flow density PAR (Photosynthetically active radiation) about 90 μmole quantum/m 2 s. at 20 W/m 2 with total light energy 54 MJ/m 2 supplied to plants from LED lamps. The plants produced about 0.5 g. of dry weight calculated on one mole of spent light energy. Energy efficiency of PAR was 3% that corresponded with data observed earlier with sodium high-pressure lamps. The conclusion was made about the suitableness of this type of light-emitting diode lamps for lettuce cultivation in winter rotation in first photic zone. It was recommended to increase duration of supplemental lighting up to 22-24 hours in December and up to 20-22 hours in January to improve the productivity and biological value of plant output. It enables to raise RAP income in plants by 35 %, on average for one cycle of cultivation.

Modelos de biomasa aérea y foliar en una plantación de pino de rápido crecimiento en Oaxaca

El vigor de un árbol se puede evaluar a partir del follaje, que si bien representa de 4% a 6% de la biomasa total del árbol, es el componente principal para los procesos fisiológicos. El objetivo de este estudio fue estimar la biomasa de acículas en ramas individuales y árbol completo, y ajustar modelos de partición de biomasa aérea en árboles plantados de Pinus patula Schl. et Cham. La biomasa de acículas por rama se estimó con un modelo lineal, que empleó área basal de rama viva, altura de rama y el seccionamiento de copa como variables independientes. La biomasa de los componentes aéreos se estimó con coeficientes de determinación de 0,86; 0,92 y 0,88; para madera con corteza, ramas y acículas, respectivamente. Para madera con corteza se utilizó el diámetro normal (DN) y altura de árbol (AT) en un modelo lineal; la biomasa de ramas y follaje con ecuaciones no lineales que se basaron en el diámetro de copa viva (DCV) y área de copa para ramas; y DCV y AT para la biomasa de follaje. La biomasa total aérea por árbol se estimó con un R2 = 0,87; utilizando DN y AT. La biomasa a una edad de 14 años se distribuyó en 92,9%; 4,7% y 2,4% para madera, ramas y follaje, respectivamente.

Developing Two Additive Biomass Equations for Three Coniferous Plantation Species in Northeast China

Accurate quantification of tree biomass is critical and essential for calculating carbon storage, as well as for studying climate change, forest health, forest productivity, nutrient cycling, etc. Tree biomass is typically estimated using statistical models. In this study, a total of 289 trees were harvested and measured for stem, root, branch, and foliage biomass from three coniferous plantation species in northeastern P.R. China. We developed two additive systems of biomass equations based on tree diameter (D) only and both tree diameter (D) and height (H). For each system, likelihood analysis was used to verify the error structures of power functions in order to determine if logarithmic transformation should be applied on both sides of biomass equations. The model coefficients were simultaneously estimated using seemingly unrelated regression (SUR). The results indicated that stem biomass had the largest relative contribution to total biomass, while foliage biomass had the smallest relative proportion for the three species. The root to shoot ratio averaged 0.27 for Korean pine, 0.25 for larch, and 0.23 for Mongolian pine. The two additive biomass systems obtained good model fitting and prediction performance, of which the model Ra2 &gt; 0.80, and the percent mean absolute bias (MAB%), was &lt;17%. The second additive system (D and H) had a relatively greater Ra2 and smaller root mean square error (RMSE). The model coefficient for the predictor H was statistically significant in eight of the twelve models, depending on tree species and biomass component. Adding tree height into the system of biomass equations can marginally improve model fitting and performance, especially for total, aboveground, and stem biomass. The two additive systems developed in this study can be applied to estimate individual tree biomass of three coniferous plantation species in the Chinese National Forest Inventory.

EMPIRICAL RELATIONSHIP BETWEEN LEAF BIOMASS OF RED PINE FORESTS AND ENHANCED VEGETATION INDEX IN SOUTH KOREA USING LANDSAT-5 TM

Research on forest carbon (C) dynamics has been undertaken due to the importance of forest ecosystems in national C inventories. Currently, the C sequestration of South Korean forests surpasses that of other countries. In South Korea, Pinus densiflora (red pine) is the most abundant tree species. Thus, understanding the growth rate and biomass evolution of red pine forest in South Korea is important for estimating the forest C dynamics. In this paper, we derived empirical relationship between foliage biomass and the no blue band enhanced vegetation index (EVI-2) profile using both field work and multi-temporal Landsat-5 TM remote sensing data to estimate the productivity of forest biomass in South Korea. Our analysis combined a set of 84 Landsat-5 TM images from 28 different dates between 1986 and 2008 to study red pine forest development over time. Field data were collected from 30 plots (0.04 ha) that were irregularly distributed over South Korea. Individual trees were harvested by destructive sampling, and the age of trees were determined by the number of tree rings. The results are realistic (R&amp;lt;sup&amp;gt;2&amp;lt;/sup&amp;gt;&amp;thinsp=&amp;thinsp0.81, &lt;i&gt;p&lt;/i&gt;&amp;thinsp;&amp;lt;&amp;thinsp;0.01) and suggest that the EVI-2 index is able to adequately represent the development profile of foliage biomass in red pine forest growth.

EMPIRICAL RELATIONSHIP BETWEEN LEAF BIOMASS OF RED PINE FORESTS AND ENHANCED VEGETATION INDEX IN SOUTH KOREA USING LANDSAT-5 TM

Abstract. Research on forest carbon (C) dynamics has been undertaken due to the importance of forest ecosystems in national C inventories. Currently, the C sequestration of South Korean forests surpasses that of other countries. In South Korea, Pinus densiflora (red pine) is the most abundant tree species. Thus, understanding the growth rate and biomass evolution of red pine forest in South Korea is important for estimating the forest C dynamics. In this paper, we derived empirical relationship between foliage biomass and the no blue band enhanced vegetation index (EVI-2) profile using both field work and multi-temporal Landsat-5 TM remote sensing data to estimate the productivity of forest biomass in South Korea. Our analysis combined a set of 84 Landsat-5 TM images from 28 different dates between 1986 and 2008 to study red pine forest development over time. Field data were collected from 30 plots (0.04 ha) that were irregularly distributed over South Korea. Individual trees were harvested by destructive sampling, and the age of trees were determined by the number of tree rings. The results are realistic (R2&amp;amp;thinsp=&amp;amp;thinsp0.81, p

Comparing tree foliage biomass models fitted to a multispecies, felled-tree biomass dataset for the United States

Estimation of live tree biomass is an important task for both forest carbon accounting and studies of nutrient dynamics in forest ecosystems. In this study, we took advantage of an extensive felled-tree database (with 2885 foliage biomass observations) to compare different models and grouping schemes based on phylogenetic and geographic variation for predicting foliage biomass at the tree scale. We adopted a Bayesian hierarchical statistical framework, first to compare linear models that predict foliage biomass directly to models that separately estimate a foliage ratio as a component of total aboveground biomass, then to compare species specific models to both ‘narrow’ and ‘broad’ general biomass models using the best fitted functional form. We evaluated models by simulating new datasets from the posterior predictive distribution, using both summary statistics and visual assessments of model performance. Key findings of our study were: (1) simple linear models provided a better fit to our data than component ratio models, where total biomass and the foliar ratio are estimated separately; (2) species-specific equations provided the best predictive performance, and there was no advantage to narrow species groupings relative to broader groups; and (3) all three model schemes (i.e., species-specific models versus narrow or broad groupings proposed in national-scale biomass equations) tended to over-predict foliage biomass and resulted in predictions with very high uncertainty, particularly for large diameter trees. This analysis represents a fundamental shift in carbon accounting by employing felled-tree data to refine our understanding of uncertainty associated with component biomass estimates, and presents an ideal approach to account for tree-scale allometric model error when estimating forest carbon stocks. However, our results also highlight the need for substantial improvements to both available fitting data and models for foliage biomass before this approach is implemented within the context of greenhouse gas inventories.

Remote sensing estimation of isoprene and monoterpene emissions generated by natural vegetation in Monterrey, Mexico.

In addition to oxygen, hydrocarbons are the most reactive chemical compounds produced by plants into the atmosphere. These compounds are part of the family of volatile organic compounds (VOCs) and are discharged in a great variety of forms. Among the VOCs produced by natural sources such as vegetation, the most studied until today are the isoprene and monoterpene. These substances can play an important role in the chemical balance of the atmosphere of a region. In this project, we develop a methodology to estimate the natural (vegetation) emission of isoprene and monoterpenes and applied it to the Monterrey Metropolitan Area, Mexico and its surrounding areas. Landsat-TM data was used to identify the dominant vegetation communities and field work to determine the foliage biomass density of key species. The studied communities were submontane scrub, oak, and pine forests and a combination of both. We carried out the estimation of emissions for isoprene and monoterpenes compounds in the different plant communities, with two different criteria: (1) taking into account the average foliage biomass density obtained from the various sample point in each vegetation community, and (2) using the foliage biomass density obtained for each transect, associated to an individual spectral class within a particular vegetation type. With this information, we obtained emission maps for each case. The results show that the main producers of isoprene are the communities that include species of the genus Quercus, located mainly on the Sierra Madre Oriental and Sierra de Picachos, with average isoprene emissions of 314.6 ton/day and 207.3 ton/day for the two methods utilized. The higher estimates of monoterpenes were found in the submontane scrub areas distributed along the valley of the metropolitan zone, with an estimated average emissions of 47.1 ton/day and 181.4 tons for the two methods respectively.

Twenty-four years after theYellowstone Fires: Are postfire lodgepole pine stands converging in structure and function?

Disturbance and succession have long been of interest in ecology, but how landscape patterns of ecosystem structure and function evolve following large disturbances is poorly understood. After nearly 25 years, lodgepole pine (Pinus contorta var. latifolia) forests that regenerated after the 1988 Yellowstone Fires (Wyoming, USA) offer a prime opportunity to track the fate of disturbance-created heterogeneity in stand structure and function in a wilderness setting. In 2012, we resampled 72 permanent plots to ask (1) How have postfire stand structure and function changed between 11 and 24 yr postfire, and what variables explain these patterns and changes? (2) How has landscape-level (among-stand) variability in postfire stand structure and function changed between 11 and 24 yr postfire? We expected to see evidence of convergence beginning to emerge, but also that initial postfire stem density would still determine trajectories of biomass accumulation. After 24 yr, postfire lodgepole pine density remained very high (mean = 21,738 stems/ha, range = 0-344,067 stems/ha). Stem density increased in most plots between 11 and 24 yr postfire, but declined sharply where 11-yr-postfire stem density was > 72,000 stems/ha. Stems were small in high-density stands, but stand-level lodgepole pine leaf area, foliage biomass, and live aboveground biomass increased over time and with increasing stem density. After 24 yr, mean annual lodgepole pine aboveground net primary production (ANPP) was high (mean = 5 Mg · ha⁻¹ · yr⁻¹, range = 0-16.5 Mg · ha⁻¹ · yr⁻¹). Among stands, lodgepole pine ANPP increased with stem density, which explained 69% of the variation; another 8% of the variation was explained by environmental covariates. Early patterns of postfire lodgepole pine regeneration, which were contingent on prefire serotiny and fire severity, remained the dominant driver of stand structure and function. We observed mechanisms that would lead to convergence in stem density (structure) over time, but it was landscape variation in functional variables that declined substantially. Stand structure and function have not converged across the burned landscape, but our evidence suggests function will converge sooner than structure.

Quantifying allometric model uncertainty for plot-level live tree biomass stocks with a data-driven, hierarchical framework

Accurate uncertainty assessments of plot-level live tree biomass stocks are an important precursor to estimating uncertainty in annual national greenhouse gas inventories (NGHGIs) developed from forest inventory data. However, current approaches employed within the United States’ NGHGI do not specifically incorporate methods to address error in tree-scale biomass models and as a result may misestimate overall uncertainty surrounding plot-scale assessments. We present a data-driven, hierarchical modeling approach to predict both total aboveground and foliage biomass for inventory plots within the US Forest Service Forest Inventory and Analysis (FIA) program, informed by a large multispecies felled-tree dataset. Our results reveal substantial plot-scale relative uncertainties for total aboveground biomass (11–155% of predicted means) with even larger uncertainties for foliage biomass (27–472%). In addition, we found different distributions of total aboveground and foliage biomass when compared with other generalized biomass models for North America. These results suggest a greater contribution of allometric models to the overall uncertainty of biomass stock estimates than what has been previously reported by the literature. While the relative performance of the hierarchical model is influenced by biases within the fitting data, particularly for woodland and conifer species, our results suggest that poor representation of individual tree model error may lead to unrealistically high confidence in plot-scale estimates of biomass stocks derived from forest inventory data. However, improvements to model design and the quality of felled-tree data for fitting and validation may offer substantial improvements in the accuracy and precision of NGHGIs.

A Comparison of Hierarchical and Non-Hierarchical Bayesian Approaches for Fitting Allometric Larch (Larix.spp.) Biomass Equations

Accurate biomass estimations are important for assessing and monitoring forest carbon storage. Bayesian theory has been widely applied to tree biomass models. Recently, a hierarchical Bayesian approach has received increasing attention for improving biomass models. In this study, tree biomass data were obtained by sampling 310 trees from 209 permanent sample plots from larch plantations in six regions across China. Non-hierarchical and hierarchical Bayesian approaches were used to model allometric biomass equations. We found that the total, root, stem wood, stem bark, branch and foliage biomass model relationships were statistically significant (p-values &lt; 0.001) for both the non-hierarchical and hierarchical Bayesian approaches, but the hierarchical Bayesian approach increased the goodness-of-fit statistics over the non-hierarchical Bayesian approach. The R2 values of the hierarchical approach were higher than those of the non-hierarchical approach by 0.008, 0.018, 0.020, 0.003, 0.088 and 0.116 for the total tree, root, stem wood, stem bark, branch and foliage models, respectively. The hierarchical Bayesian approach significantly improved the accuracy of the biomass model (except for the stem bark) and can reflect regional differences by using random parameters to improve the regional scale model accuracy.

Foliage biomass and specific leaf area equations at the branch, annual shoot and whole-tree levels for lodgepole pine and white spruce in British Columbia

The distribution and characteristics of foliage are important aspects of tree structure and have implications for the productivity of individual trees and whole stands. We modelled foliage biomass and specific leaf area (SLA) using a sample of 60 lodgepole pine (Pinus contorta) and 60 white spruce (Picea glauca) that were destructively sampled in British Columbia, Canada. We modelled foliage biomass and SLA at three scales of organization: individual primary branches, annual shoots (all branches on an annual increment of the main stem), and the whole tree. We used a variety of independent variables that range in scale from the branch to plot level. Models of foliage biomass and SLA differ substantially between the two species even though their basic architectural design is quite similar. Models differed notably among levels of organization. For branch-level biomass, relevant variables for both species included branch diameter, length, age, distance to the crown base, and a measure of crown contact; however, at the annual-shoot level, relevant explanatory variables were mostly different between the species. At the whole tree-level, only crown length was common to both species and all other explanatory variables differed. SLA was higher in spruce than pine for all age classes and canopy positions. Overall, the models allow prediction of important crown properties for two major conifers at a range of scales, and can thus contribute to better prediction of stand growth and other properties.

Additive biomass equations for small diameter trees of temperate mixed deciduous forests

ABSTRACTThe carbon stored in small diameter trees of temperate forests has been ignored in most studies and there is a lack of biomass equations for this component of forests. We harvested nine main tree species at sapling stage (dbh < 8 cm) across different site conditions (from 100 to 1700 m a.s.l). For each species, 10–12 individuals were selected randomly and harvested. Using nonlinear seemingly unrelated regression (NSUR), additive species-independent equations were developed for estimation of biomass of foliage, branch, bole, and total based on dbh, height, and wood density as predictors. Results showed that wood density and height had high effects on equations performance except for the foliage equations. Comparing actual and estimated biomass for each species revealed that these equations can be used for new species in similar forests.

Pipe-model ratio distributions and branch foliage biomass: differences between two sympatric spruce species

The foliage biomass–sapwood relationship (the pipe model) is critical for tree growth and is used in tree growth models for understanding the implications of this structural relationship on the allocation of resources. In this research, we compared this relationship for two commercially important and sympatric species, black spruce (Picea mariana (Mill.) B.S.P.) and white spruce (Picea glauca (Moench) Voss). At locations in eastern Canada, 57 black and 50 white spruce trees were destructively sampled to obtain foliage biomass, crown structure, and tree stem measures. Using a model-based approach, we compared foliage biomass–branch basal area and foliage biomass–sapwood relationships at the tree and disk (i.e. along the tree stem) levels (i.e. pipe-model ratios) between these two species. We found that (i) branch foliage biomass–branch basal area was greater for black spruce than white spruce and (ii) pipe-model ratios along the tree stem given tree size were greater for black spruce than for white spruce. We attributed these differences to: (i) greater shade tolerance and leaf longevity of black spruce; (ii) slower growth rates of black spruce; and (iii) differing hydraulic strategies and mechanical requirements.

Additive Tree Biomass Equations for Midrotation Loblolly Pine Plantations

Biomass estimation is a prerequisite for calculating biomass energy, carbon storage, and sequestration of forests and for examining forest productivity and nutrient cycling. With destructive biomass sampling data from 456 sampled trees on 114 plots of loblolly pine culture and density studies at ages 12, 15, and 16, two systems of nonlinear additive tree biomass equations were developed. One was based on DBH, tree height, live crown length and width, and diameter at live crown base, and the other was based on DBH and tree height only. The systems guarantee additivity in biomass equations. The nonlinear seemingly unrelated regressions (NSUR) approach was used to account for the inherent correlation among the biomass equations, and heteroscedasticity was addressed by having a unique weighting function for each equation. 1 Both systems of biomass equations were compared with previously published equations and the new ones provided more accurate predictions, especially with respect to branch and foliage biomass. The new systems can be used to accurately estimate tree component or total tree aboveground biomass of midrotation loblolly pine plantations in the southeastern United States.

A STRUCTURALLY BASED ANALYTIC MODEL OF GROWTH AND BIOMASS DYNAMICS IN SINGLE SPECIES STANDS OF CONIFERS

ABSTRACTA theoretically based analytic model of plant growth in single species conifer communities based on the species fully occupying a site and fully using the site resources is introduced. Model derivations result in a single equation simultaneously describes changes over both, different site conditions (or resources available), and over time for each variable for each species. Leaf area or biomass, or a related plant community measurement, such as site class, can be used as an indicator of available site resources. Relationships over time (years) are determined by the interaction between a stable foliage biomass in balance with site resources, and by the increase in the total heterotrophic biomass of the stand with increasing tree size. This structurally based, analytic model describes the relationships between plant growth and each species’ functional depth for foliage, its mature crown size, and stand dynamics, including the self‐thinning. Stand table data for seven conifer species are used for verification of the model. Results closely duplicate those data for each variable and species. Assumptions used provide a basis for interpreting variations within and between the species. Better understanding of the relationships between the MacArthur consumer resource model, the Chapman–Richards growth functions, the metabolic theory of ecology, and stand development resulted.

Integrated individual tree biomass simultaneous equations for two larch species in northeastern and northern China

Forest biomass estimation at large scale has become an important topic in the background of facing global climate change, and it is fundamental to develop individual tree biomass equations suitable for large-scale estimation. Based on the measured data of biomass components and stem volume from 100 sample trees of two larch species (Larix gmelinii and L. principis-rupprechtii) in northeastern and northern China, an integrated equation system including individual tree biomass equations, stem volume equation and height–diameter regression model were constructed using the dummy variable model and error-in-variable simultaneous equations. In the system, all the parameters of equations were estimated simultaneously, so that the aboveground biomass equation was compatible to stem volume equation and biomass conversion factor (BCF) function; the belowground biomass equation was compatible to root-to-shoot ratio (RSR) function; and stem wood, stem bark, branch and foliage biomass equations were additive to aboveground biomass equation. In addition, the system also ensured the compatibility between one- and two-variable models. The results showed that: (1) whether aboveground biomass equations or belowground biomass equations and stem volume equations, the estimates for larch in northeastern China were greater than those in northern China; (2) BCF of a larch tree decreased with the growing diameter while RSR increased with the growing diameter; (3) the proportion of stem wood biomass to aboveground biomass increased with the growing diameter while those of stem bark, branch, and foliage biomass decreased.