Based on a generated database of 413 sample plots, with definitions of stand biomass of the genus Populus spp. in Eurasia, from France to Japan and southern China, statistically significant changes in the structure of forest stand biomass were found, with shifts in winter temperatures and average annual precipitation. When analyzing the reaction of the structure of the biomass of the genus Populus to temperature and precipitation in their transcontinental gradients, a clearly expressed positive relationship of all components of the biomass with the temperature in January is visible. Their relationship with precipitation is less clear; in warm climate zones, when precipitation increases, the biomass of all wood components decreases intensively, and in cold climate zones, this decrease is less pronounced. The foliage biomass does not increase when precipitation decreases, as is typical for wood components, but decreases. This can be explained by the specifics of the functioning of the assimilation apparatus, namely its transpiration activity when warming, and the corresponding increase in transpiration, which requires an increase in the influx of assimilates into the foliage, and the desiccation of the climate that reduces this influx of assimilates. Comparison of the obtained patterns with previously published results for other species from Eurasia showed partial or complete discrepancies, the causes of which require special physiological studies. The results obtained can be useful in the management of biosphere functions of forests, which is important in the implementation of climate stabilization measures, as well as in the validation of the results of simulation experiments to assess the carbon-deposition capacity of forests.

Based on the generated database of 413 and 490 plots of biomass of Populus spp. and Betula spp. in Eurasia, statistically significant changes in the structure of forest stand biomass were found with shifts in January temperatures and average annual precipitation. When analyzing harvest data, the propeller-shaped biomass patterns in the gradients of average annual precipitation and average January temperatures are obtained, which are common for both deciduous species. Correspondingly, Populus and Betula forests show a regularity common to the biomass components: in the cold zones the precipitation increase leads to the increase of biomass, and in the warm ones to their decrease. In wet areas, the increase of temperature causes the decrease of biomass, and in dry areas, it causes their increase. In accordance with the law of the limiting factor by Liebig-Shelford, it is shown that both an decrease in temperature in dry conditions and a increase in precipitation in a warm climate lead to a decrease in the biomass of trees.

A comparative discussion of the advantages and disadvantages of natural stands and plantations, including in terms of their productivity and stability, began from the moment of the first forest plantings and continues to this day. In the context of the progressive replacement of natural forests by plantations due to deforestation, the question of how will change the carbon storage capacity of forest cover when replacing natural forests with artificial ones in a changing climate becomes extremely relevant. This article presents the first attempt to answer this question at the transcontinental level on a special case for two-needled pine trees (subgenus Pinus L.). The research was carried out using the database compiled by the authors on the single-tree biomass structure of forest-forming species of Eurasia, in particular, data of 1880 and 1967 of natural and plantation trees, respectively. Multi-factor regression models are calculated after combining the matrix of initial data on the structure of tree biomass with the mean January temperature and mean annual precipitation, and their adequacy indices allow us to consider them reproducible. It is found that the aboveground and stem biomass of equal-sized and equal-aged natural and plantation trees increases as the January temperature and precipitation rise. This pattern is only partially valid for the branches biomass, and it has a specific character for the foliage one. The biomass of all components of plantation trees is higher than that of natural trees, but the percent of this excess varies among different components and depends on the level of January temperatures, but does not depend at all on the level of annual precipitation. A number of uncertainties that arose during the modeling process, as well as the preliminary nature of the obtained regularities, are noted.

Для оценки углероддепонирующей способности лесов Уральского региона необходимы аллометрические модели зависимости биомассы от диаметра ствола. Подобные модели особенно перспективны в условиях Урала, где преобладают древостои смешанного породного состава, и модели биомассы, рассчитанные на уровне древостоев, могут иметь смещения, вызванные изменчивостью породного состава. В работе предложены аллометрические модели для компонентов надземной биомассы деревьев лесообразующих пород Урала, которые характеризуются высокими показателями адекватности исходным данным. Вследствие нехватки фактических данных о биомассе корней для каждой породы предложены средние значения относительного показателя как отношения массы корней к надземной. Полученные результаты могут быть полезны при мониторинге углероддепонирующей способности лесного покрова Уральского региона.Ключевые слова: надземная биомасса, компоненты биомассы, масса корней, относительная масса корней, аллометрические модели биомассы To assess the carbon depositing capacity of forests in the Ural region, allometric models of the dependence of biomass on stem diameter are needed. Such models are especially promising in the conditions of the Urals, where stands of mixed species composition prevail, and biomass models calculated at the level of stands will have displacements caused by the variability of the species composition. The paper proposes allometric models for the components of the aboveground biomass of trees of forest-forming species of the Urals, which are characterized by high indicators of adequacy in relation to the initial data. Due to the lack of actual data on root biomass, average values of the relative indicator as the ratio of root mass to aboveground one are proposed for each species. The results obtained can be useful in monitoring the carbon depositing capacity of the forest cover of the Ural region.

On the basis of the compiled database in a number of 413 sample plots with determinations of forest biomass of the genus Populus sp. on the territory of Eurasia from France to southern China and Japan statistically significant transcontinental decreasing of stem, above ground and total biomass as...

Пространственно-временнóе замещение означает использование современных закономерностей и явлений, наблюдаемых в пространственных градиентах, для понимания и моделирования тех же закономерностей и процессов в ретроспективных и перспективных градиентах времени, которые на данный момент не поддаются наблюдению. Считается, что статистическую взаимосвязь между факторами окружающей среды и реакцией экосистем лучше всего выявить на основе наблюдений в течение длительного периода времени. Однако во многих случаях долгосрочные данные временных рядов недоступны, и тогда исследователи в своих моделях заменяют временные данные пространственными данными. Истоки теории пространственно-временного замещения восходят в XIX в., когда немецкий физик Больцман разработал кинетическую теорию газов. В наши дни методы, основанные на пространственно-временном замещении, применяются в разных областях: палеоклиматологии, геоморфологии, ландшафтоведении и экологических исследованиях. Метод пространственно-временного замещения используется в лесной таксации для построения таблиц хода роста путем подбора древостоев одного естественного ряда, а в лесной экологии – при прогнозировании растительных сукцессий, в частности восстановительно-возрастного морфогенеза таежных лесов. В связи с прогрессирующими климатическими изменениями применение метода пространственно-временного замещения в экологии является особенно актуальным. При построении трансконтинентальных моделей биомассы, чувствительных к изменению климата, на основе принципа пространственно-временного замещения установлено, что зависимость биомассы от температур и осадков описывается пропеллерообразной 3D-поверхностью. В холодных регионах при повышении осадков биомасса снижается, но по мере перехода к теплым регионам она характеризуется противоположным трендом; при повышении температуры во влажных регионах биомасса увеличивается, но по мере перехода в сухие условия снижается. Тем самым подтверждено действие закона лимитирующего фактора в отношении лесных сообществ в условиях изменения климата. Применение метода пространственно- временного замещения связано с рядом неопределенностей, и одна из них устанавливается разными адаптационными возможностями древесных растений, иногда даже у разных видов в пределах рода. Тем не менее, когда нет иной возможности исследовать экосистемные процессы в ретроспективе или перспективе, метод пространственно-временного замещения представляет вполне приемлемую альтернативу. Space-for-time substitution means the use of modern patterns and phenomena observed in spatial gradients to understand and model the same patterns and processes in retrospective and prospective temporal gradients that are currently not observable. It is believed that the statistical relationship between environmental factors and the response of ecosystems is best identied using observations over a long period of time. However, in many cases, long-term time series data is not available, and then researchers in their models replace the temporal data with spatial data. The origins of the theory of space-time substitution go back to the XIX century, when the German physicist Boltzmann developed the kinetic theory of gases. Nowadays, methods based on space-for-time substitution are used in variouselds: paleoclimatology, geomorphology, landscape sciences and environmental studies. The method of space-for-time substitution is used in forest taxation to build forest yield tables by selecting stands of one natural sequence of different ages, and in forest ecology – when predicting plant successions, in particular, the restoration-age morphogenesis of taiga forests. Due to the progressive climatic changes, the use of the method of space-for-time substitution in ecology is especially relevant. When constructing transcontinental models of biomass sensitive to climate...