Current carbon storage in forests of two ecoregions of Russia

В связи с глобальным потеплением климата оценка углеродного цикла в лесных экосистемах приобрела особое значение. Один из методов определения депонированного в лесах углерода основан на использовании конверсионных коэффициентов биомассы (ККБ) и данных Государственного учета лесного фонда (ГУЛФ). Путем объединения моделей ККБ с данными ГУЛФ в двух экорегионах России – таежном и лесостепном – было установлено, что за 20–25- летний период накопление органического углерода в таежной зоне значительно меньше (5%) по сравнению с лесостепной зоной (39%). Несмотря на существующие риски стихийных бедствий в лесостепном экотоне, за четверть века наблюдается значительный рост депонированного углерода. Это произошло вследствие высокой доли молодняков в начале анализируемого периода, обладающих повышенным приростом по отношению к спелым древостоям. Сопоставимые результаты были получены одним и тем же методом в разных экорегионах планеты: от 8% за 5 лет в Китае до 68% за 50 лет в Японии. Сравнение результатов, полученных предложенным методом и методом IIASA (Австрия), показало минимальное расхождение (3%), что дает основание считать полученные оценки депонирования углерода близкими к реальности. Однако сохраняется неопределенность, связанная с качеством данных ГУЛФ и депонированием углерода в почве. Due to the global warming of the climate, the assessment of the carbon cycle in forest ecosystems has become particularly important. One method for determining deposited carbon is based on the use of biomass expansion factors (BEF) and State Forest Inventory (SFI) data. By combining BEF models with SFI data in two ecoregions of Russia – taiga and forest-steppe – it was found that over a 20–25-year period, accumulating the carbon deposition in the taiga zone is significantly less (5%) compared to the forest-steppe zone (39%). Despite the existing risks of natural disasters in the forest-steppe ecotone, there is a significant increase in carbon deposition over a quarter of a century. This was due to the high proportion of young stands at the beginning of the analyzed period, which have increased growth in relation to old stands. Comparable results were obtained by the same method in different ecoregions of the planet (from 8% in 5 years in China to 68% in 50 years in Japan). A comparison of the results obtained by the proposed method and the IIASA (Austria) method showed a minimal discrepancy (3%), which gives reason to consider the above estimates of carbon deposition close to reality. However, uncertainties remain related to the quality of the SFI data and the carbon deposition in the soil.

A Methodology to Estimate the Potential Production of Bioenergy Based on the Species, Cultivation Area Conditions, and Period of Forest Trees

Introduction : Since the population increases and the industry develops, the demand for fossil fuels continues to increase, creating problems of energy resource depletions and accelerating global warming. Thus, many countries are making active efforts to replace fossil fuels with bioenergy as a renewable energy. In particular, trees managed and produced by forest industry have a high potential as energy sources for biofuel industry, because they have a conceptual characteristic of carbon neutrality. Recently, energy plan and policy are being developed to cultivate trees on fallow lands, environmentally restored sites, and ground-level work places of abandoned mines; however, economic feasibility for such plans and policies cannot be readily evaluated due to insufficient information on the amount of the energy to be produced from tree cultivation. Thus, the objective of this study is to develop a methodology which can be used to estimate the potential energy amount of the bioenergy from tree cultivation based on tree species, cultivation time, and cultivation area conditions.Methodology : The methodology consists of three stages. In the first stage, the total volume of the trees per area is estimated by using the number of trees per unit area and the average stem volume of the tree, which are affected by the site index representing the environmental conditions of cultivation area. In the second stage, the total mass of biomass is calculated by using the density of wood, the biomass expansion factors for the above-ground biomass, and root-shoot ratio. In the last stage, the amount of the energy produced from the tree cultivation is estimated by taking into account the caloric value evaluated based on the carbon, hydrogen, and oxygen compositions of the tree.Case Study : A case study for conifers and broad-leaved trees is performed to demonstrate the methodology. The conifers are Jungbu local pine, Korean white pine, and Japanese larch, and the broad-leaved trees are oak, red oak, and birch. The results of the case study validate the developed methodology and clearly showed the procedure and necessity for the methodology by estimating the bioenergy productions from the trees.Conclusions : The developed methodology can be used to provide practical information needed to determine the economic feasibility of the plan, policy, and project for tree cultivations.

Allometric Relationships for Estimation of Above-Ground Biomass in Young Turkey Oak (Quercus cerris L.) Stands in Albania

The study objective was the determination of allometric relationships to estimate aboveground biomass in young Q. cerris stands growing in various sites in Albania. The equations described here are developed for Q. cerris forest stands managed as coppice. The total aboveground biomass of sampled trees varied from 10.67 to 19.71 kg with a stem diameter at 1.3 m (DBH) from 7.65 to 9.7 cm, and height from 5.26 to 7.6 m. Stem biomass comprised, on average, 69.6 %, while branch biomass was 24.3 %, and leaf biomass,6% on the total aboveground biomass of the sampled oak trees. Total aboveground biomass was predicted with the highest accuracy from linear and non-linear regression equations. Total aboveground biomass and the biomass of tree compartments were predicted with a notable accuracy from DBH where the allometric model efficiency exceeded 93%. Biomass expansion factors (BEFs) showed a stronger dependency on diameter at breast height and a weaker relationship with age. The age-dependence relationship found in our study was closely related to site productivity. The variability in aboveground biomass among sampled sites indicated that local site conditions cause this difference. These new equations for Q.cerris might be applicable in the framework of the Albanian National Forest Inventory for estimation of carbon accounting from forest ecosystems and will contribute to the sustainable management of oak forests.