Vladimir Usoltsev

How does biomass distribution change with size and differ among species? An analysis for 1200 plant species from five continents

Summary We compiled a global database for leaf, stem and root biomass representing c. 11 000 records for c. 1200 herbaceous and woody species grown under either controlled or field conditions. We used this data set to analyse allometric relationships and fractional biomass distribution to leaves, stems and roots. We tested whether allometric scaling exponents are generally constant across plant sizes as predicted by metabolic scaling theory, or whether instead they change dynamically with plant size. We also quantified interspecific variation in biomass distribution among plant families and functional groups. Across all species combined, leaf vs stem and leaf vs root scaling exponents decreased from c. 1.00 for small plants to c. 0.60 for the largest trees considered. Evergreens had substantially higher leaf mass fractions (LMFs) than deciduous species, whereas graminoids maintained higher root mass fractions (RMFs) than eudicotyledonous herbs. These patterns do not support the hypothesis of fixed allometric exponents. Rather, continuous shifts in allometric exponents with plant size during ontogeny and evolution are the norm. Across seed plants, variation in biomass distribution among species is related more to function than phylogeny. We propose that the higher LMF of evergreens at least partly compensates for their relatively low leaf area : leaf mass ratio.

Allometric equations for integrating remote sensing imagery into forest monitoring programmes

Abstract Remote sensing is revolutionizing the way we study forests, and recent technological advances mean we are now able – for the first time – to identify and measure the crown dimensions of individual trees from airborne imagery. Yet to make full use of these data for quantifying forest carbon stocks and dynamics, a new generation of allometric tools which have tree height and crown size at their centre are needed. Here, we compile a global database of 108753 trees for which stem diameter, height and crown diameter have all been measured, including 2395 trees harvested to measure aboveground biomass. Using this database, we develop general allometric models for estimating both the diameter and aboveground biomass of trees from attributes which can be remotely sensed – specifically height and crown diameter. We show that tree height and crown diameter jointly quantify the aboveground biomass of individual trees and find that a single equation predicts stem diameter from these two variables across the worlds forests. These new allometric models provide an intuitive way of integrating remote sensing imagery into large‐scale forest monitoring programmes and will be of key importance for parameterizing the next generation of dynamic vegetation models.

Modelling root biomass distribution in Pinus sylvestris forests of the Turgai Depression of Kazakhstan

Abstract Tree roots contain a high proportion of forest biomass, but methods to describe root biomass vary greatly due to the emphasis of different studies and different excavation methods used. In this paper, total root biomass and root distribution data of 27 trees from the northern Kazakh steppe were approximated by allometric functions depending on tree height, stump diameter, root diameter class, and optionally, depth in the ground. Our regressions offer good overall approximations to the data except for the uppermost horizon and the thickest roots (which include the stump). Logarithmic standard deviations range from 0.23 to 0.39 for total root biomass and from 0.74 to 1.09 for root distribution, and R 2 range from 0.96 to 0.98 and from 0.76 to 0.89, respectively. Although the original goal of constructing a cumulative function in both root diameter class and depth in the ground was not attained due to unfavourable statistical conditions, bivariate interpolation can be used with our functions to overcome the limitations of the set of class boundaries used. In addition, regressions were developed which eliminate the need to measure stump diameter and maximum depth of root penetration.

Tree-crown biomass estimation in forest species of the Ural and of Kazakhstan

Abstract Tree foliage biomass forms an essential element in forest modelling. Its measurement is costly and its relation to other measurements of standing trees have come under closer scrutiny since the introduction of the pipe model. Regressions of foliage and green shoot biomass of various levels of complexity are given, using as predictors diameter at the base of the crown ( d c ), mean diameter increment, diameter at breast height ( d ) and age ( t ). Most economical and relatively precise are two separate regressions, one for broad-leaved and one for coniferous species each, using d c only. Approximations for coniferous foliage can be improved considerably by allowing parallel regressions and including mean diameter increment and diameter at breast height as predictors. We found that tree age is less influential than mean increment. For shoot biomass parallel regressions on d c are optimal.

Stand Biomass Dynamics of Pine Plantations and Natural Forests on Dry Steppe in Kazakhstan

Biomass dynamics were studied in isolated relict stands of Scots pine (Pinus sylvestris L.) on the dry steppe of Kazakhstan (53–54° N), where potential evaporation is 500–600 mm yr−1 and the rainfall is 250–260 mm yr−1. Samples were taken from seven plots in natural stands on sandy forest soils (aged 13–110 yrs) and ten plots in plantations on dark‐chestnut‐coloured soils (aged 5–50 yrs). Nine or ten sample trees were taken from each plot, giving a total of 68 and 96 sample trees in natural and plantation stands respectively. Root systems were excavated and fractionated in 11 plots. Analyses indicated that the stability of these stands becomes critical at 10–20 yrs, when foliage biomass reaches its maximum (7–13 t ha−1 dry weight), both in plantations and natural stands. Self‐regulating mechanisms in natural stands provide stability that may not develop in some plantations. Natural stands may show an abrupt decrease in foliage biomass at the time of canopy closure, but it increases again by age 40–50 yrs....

Combining harvest sample data with inventory data to estimate forest biomass

Forest biomass databases which go beyond stem volume are needed for carbon balance calculations and also for forest monitoring, forest damage inventories and the solution of other related problems. In this article, it is shown how recursive multiple regression analysis can combine forest inventory data with biomass harvest data. The stand‐level conversion factor derived for Pinus sylvestris L. branch biomass for the “Severka”; Forest Farm shows a reasonable goodness of fit, with a coefficient of determination of R2 = 0.87. Statistically significant coefficients were achieved by including stand density and the quadratic mean diameter in the regression. Equations developed for Switzerland, using Burgers Picea abies (L.) Karst. branch and needle conversion factors for individual trees, show R2 = 0.87 and R 2 = 0.91, achieved by taking h dom.50, elevation, diameter at breast height and age into account.

Advanced Sintering Techniques in Design of Planar IT SOFC and Supported Oxygen Separation Membranes

Thin film solid oxide fuel cells (SOFC) operating in the intermediate temperature (IT) range are now considered as promising for distributed, mobile, standby or auxiliary power generation. At present one of the most important scientific aims in design of solid oxide fuel cells is to lower the operating temperatures to 600-800 С. In this temperature range, majority of problems inherent to SOFC operating at high (950-1000 C) are alleviated. Thus, cations interdiffusion and solid state reactions between electrolyte and electrodes are hampered and thermal stresses are decreased which prevent degradation of the functional layers [Yamamoto, 2004 ]. Hence, design of thin film SOFC requires also elaboration of nanostructured electrodes compatible with electrolytes from chemical and thermophysical points of view and providing a developed three-phase boundary (TPB). In this respect, broad options are provided by design of nanocomposite mixed ionic-electronic conducting (MIEC) functional layers – (Sadykov et al., 2010; Sadykov et al., 2009; Sadykov et al., 2008).

Metal Supported SOFC on the Gradient Permeable Metal Foam Substrate

Gradient permeable metallic substrate material consisting of two layers of NiAl alloy was developed for the SOFC design. The open-cell foam layer (thickness 1-2 mm, cell density 60 ppi) provides the structure robustness, while a thin (100-200 μm) mesoporous layer facilitates supporting functional layers. Cathode layers (LSM, LSFN and their nanocomposites with GDC or YSZ) and anode layers (NiO/YSZ, NiO/YSZ +Ru/Ln-Sr-Mn-Cr-O nanocomposite catalyst) were deposited by slip casting, electrophoretic deposition or air brushing. Thin (5-10 μm) YSZ layer was deposited by MO CVD. Power density up to 550 mW/cm2 at 700oC was obtained on button-size cells using wet H2-air feeds.

Estimating the Carbon Pool in the Phytomass of Larch Forests in Northern Eurasia

A data bank on larch phytomass was compiled on the basis of 60 publications describing the data obtained on 360 plots distributed over the area extending from England to Japan. These data were used for calculating conversion factors, i.e., the ratios of carbon pools in trunks, roots, skeletal branches, foliage, and understory (metric tons per hectare) to standing crop (m3/ha). The systems of recursive equations for estimating both volume-forming indices and conversion factors and combined into a second-level recursion system were calculated for 21 regions and forest formations of Northern Eurasia. The values of organic carbon pool in phytomass fractions were estimated for each region and formation.

Methods and results of studying the geographical trends in the structure of single-tree biomass of larches and two-needled pines in Eurasia

First transcontinental changes in fractional composition of sample tree biomass of larches (Larix Mill.) and two-needled pines (subgenus Pinus) are reported, taking into account their regional differences by age, tree height, stem diameter, and volume, as well as tree density. All components of the tree biomass of larches and pines monotonically increases from the North to the South. Dynamics of pine biomass in the direction from the Atlantic and Pacific coasts to the continentality pole in Siberia is characterized by monotonous decrease of all components, including the roots. The latter is in contradiction with the change of the larch root biomass across the same gradient of climate continentality, which, unlike the mass of pine roots, is not reduced, but increased. The system of the transcontinental dependencies obtained allows its use in estimating forest biomass based on the local data of a tree enumeration per ha.