A Simulation Model of Environmental Processes and Vegetation Patterns in Boreal Forests: Test Case Fairbanks, Alaska

In this study, a simulation model of environmental processes in upland boreal forests was combined with a gap model of species-specific demographic responses to these processes. Required parameters consisted of easily obtainable climatic, soils, and species parameters. The model successfully reproduced seasonal patterns of solar radiation, soil moisture, and depths of freeze and thaw for different topographies at Fairbanks, Alaska. The model also adequately simulated stand structure and vegetation patterns for boreal forests in the uplands of interior Alaska. These analyses suggest that this modeling approach is valid for upland boreal forests in interior Alaska and have identified the critical processes and parameters required to understand the ecology of these forests. If validated in other bioclimatic regions, this model may provide a framework for a circumpolar comparison of boreal forests and a mechanistic context for bioclimatic classifications of boreal forest regions

The Silvics of Some East European and Siberian Boreal Forest Tree Species

In recent years, the boreal forest has received increased scientific attention in light of projected climatic warming to boreal regions from increased concentrations of atmospheric carbon dioxide. The ecological consequences of such a warming could be significant. However, before the consequences of climatic change can be properly investigated, the ecology of boreal forest tree species must be adequately understood. Though the life-histories of many North American boreal forest tree species are well known, little comparable information has been compiled in English for the major boreal forest tree species of the Soviet Union. In this paper, we present a preliminary description of the silvics of seven of these species -- their ranges, optimum climatic and soil conditions, regeneration characteristics, tree growth features, responses to suboptimal site conditions, and reaction to fire. We hope that this information will provide a useful data base for use in modeling the ecology of these species

Active Amplification of the Terrestrial Albedo to Mitigate Climate Change: An Exploratory Study

This study explores the potential to enhance the reflectance of solar insolation by the human settlement and grassland components of the Earth's terrestrial surface as a climate change mitigation measure. Preliminary estimates derived using a static radiative transfer model indicate that such efforts could amplify the planetary albedo enough to offset the current global annual average level of radiative forcing caused by anthropogenic greenhouse gases by as much as 30 percent or 0.76 W/m2. Terrestrial albedo amplification may thus extend, by about 25 years, the time available to advance the development and use of low-emission energy conversion technologies which ultimately remain essential to mitigate long-term climate change. However, additional study is needed to confirm the estimates reported here and to assess the economic and environmental impacts of active land-surface albedo amplification as a climate change mitigation measure.Comment: 21 pages, 3 figures. In press with Mitigation and Adaptation Strategies for Global Change, Springer, N

Uncertainties in climate responses to past land cover change: First results from the LUCID intercomparison study

Seven climate models were used to explore the biogeophysical impacts of human-induced land cover change (LCC) at regional and global scales. The imposed LCC led to statistically significant decreases in the northern hemisphere summer latent heat flux in three models, and increases in three models. Five models simulated statistically significant cooling in summer in near-surface temperature over regions of LCC and one simulated warming. There were few significant changes in precipitation. Our results show no common remote impacts of LCC. The lack of consistency among the seven models was due to: 1) the implementation of LCC despite agreed maps of agricultural land, 2) the representation of crop phenology, 3) the parameterisation of albedo, and 4) the representation of evapotranspiration for different land cover types. This study highlights a dilemma: LCC is regionally significant, but it is not feasible to impose a common LCC across multiple models for the next IPCC assessment