Alexander Onuchin

Responses of High Latitude Ecosystems to Global Change: Potential Consequences for the Climate System

Terrestrial ecosystems of high latitudes occupy approximately one-fourth of the Earths vegetated surface. Substantial climatic warming has occurred in many high latitude areas during the latter half of the 20 th Century (Serreze et al. 2000), and evidence continues to mount that this warming has been affecting the structure and function of terrestrial ecosystems in this region (Stow et al. 2004; Hinzman et al. 2005). It is important to understand these changes because they may have consequences for the functioning of the climate system, particularly in the way that (a) radiatively active gases are exchanged with the atmosphere, (b) water and energy are exchanged with the atmosphere, and (c) fresh water is delivered to the Arctic Ocean (Chapin et al. 2000a; McGuire et al. 2003). The exchange of water and energy has implications for regional climate that may influence global climate, while the exchange of radiatively active gases and the delivery of fresh water to the Arctic Ocean are processes that could directly influence climate at the global scale. Over the past decade the IGBP-GCTE high latitude transects have become important foci for research on responses of high latitude terrestrial regions to global which has been augmented by carbon storage studies along a transect in Finland; one in Canada, the Boreal Forest Transect Case Study (BFTCS); and one in Alaska. The high latitude transects generally span substantial temperature gradients (mean annual temperature of 5° to –15°C) both within and among transects (McGuire et al. 2002). Temperature along each transect co-varies with precipitation and photosynthetically active radiation. Disturbance regimes including fire and insects are also variable among the high latitude transects. For example, fire is essentially non-existent in much of Scandinavia, but burns annually an average of approximately 1% of the boreal forest along the EST (McGuire et al. 2002; Fig. 24.2). Similarly, land-use and land-cover change also varies among the high latitude transects (Kurz and Apps 1999; McGuire et al. 2002, 2004). Each of the transects provides a different perspective into the responses of high latitude ecosystems to global change. In this chapter we first summarize how climate, disturbance regimes, and land cover in high latitudes have changed during the last several decades. We then summarize the results of ecological research along these transects that have contributed towards a richer understanding of high latitude terrestrial responses to these changes. We conclude with a discussion of challenges and opportunities for integration. …

Needle, crown, stem, and root phytomass of Pinus sylvestris stands in Russia

Abstract With growing concern about predicted global warming, increasing attention is being paid to the phytomass (living plant mass) components of forest stands and their role in the carbon cycle. The ability to predict phytomass components from commonly available inventory data would facilitate our understanding of the latter. We focus on Scots pine ( Pinus sylvestris L.) stands in Russia, with the objective of predicting stand phytomass (Mg ha −1 ) for the four major stand components: needles, crown, stems, and roots. The study area includes regions in Russia where Scots pine is a stand-forming species: from European Russia (33°E) to Yakutia (130°E) in eastern Siberia. To ensure that results will be widely applicable, only variables consistently measured in forest inventories were considered as possible predictors: stand age, site quality class, and stocking (stand stem volume with bark, m 3 ha −1 ). Stand phytomass data were obtained from numerous regional and local phytomass studies, and supplemented with additional unpublished data. This is the first comprehensive study synthesizing stand level phytomass relations for P. sylvestris for most of its range in Russia. The combined results from over 18 regional and local phytomass studies provide a level of generality that is not possible with individual local studies. In addition to estimating stand phytomass components across a wide range of conditions, these phytomass models can also be used to verify carbon allocation rules in process-based models.

Terrestrial ecosystems and their change

This chapter considers the current state of Siberian terrestrial ecosystems, their spatial distribution, and major biometric characteristics. Ongoing climate change and the dramatic increase of accompanying anthropogenic pressure provide different but mostly negative impacts on Siberian ecosystems. Future climates of the region may lead to substantial drying on large territories, acceleration of disturbance regimes, deterioration of ecosystems, and positive feedback to global warming. The region requires urgent development and implementation of strategies of adaptation to, and mitigation of, negative consequences of climate change.

Transition to Sustainable Forest Management in Russia: theoretical and methodological backgrounds (In Russian)

The paper contains a short analysis of theoretical and methodological backgrounds of transition to sustainable forest management in Russia (SFM). It is concisely considered the current state of forest management in Russia which is estimated as critical; expected impacts of climate change on the country’s forests; and theoretical and methodological prerequisites, specifics and risks of transition to SFM including 1) concept and general methodological basis of transition to SFM; 2) specifics of the required information; 3) problem of forest protection in conditions of growing risks; 4) strategic prerequisites of adaptation of forests to climate change and their use as a tool of climate change mitigation; and 5) necessity of a harmonized estimation of diversity of resources and other forest ecosystem services within the paradigm of risk resilient forest management. A crucial role of models of different complexity and destination is considered as a basic methodological tool of long-term planning of forest management actions. It is shown that there is no single strategy, which would allow reaching all goals of SFM. The scale of objects within which SFM is implemented might play a crucial role in finding the optimal decisions. Similar to many other countries, Russia is late with consideration and implementation of SFM. The paper is limited by theoretical and methodological questions and does not touch upon managerial, institutional and political problems of the up-to-date forest sector of Russia.

CARBON BALANCE AND THE EMISSION OF GREENHOUSE GASES IN BOREAL FORESTS AND BOGS OF SIBERIA

Zonal patterns of above-ground phytomass dynamics and carbon storage in above-ground vegetation, phytodetritus and humus were revealed based on the study of the carbon balance and its components in forest ecosystems of the Yenisei meridian transect. Results indicate that the carbon storage ratio in different plant layers is determined by climatic regimes. For example pine stands were used to calculate the full carbon budget using data on its fluxes and storage in different biogeocenosis components. Biological productivity indices and the carbon pool of hydromorphic complexes are highly dependant on the mineral nutrition regime and morphological characteristics of the stands. Experimental study results show the importance of forest and bog ecosystems as carbon cycle regulators is determined by the complex interaction of zonal-climatic and forest conditions as well as by forest vegetation characteristics (which depend on varying carbon balance structure and energymass exchange processes).