The sensitivity of some high-latitude boreal forests to climatic parameters |
| |
| Authors: | Gordon B Bonan Herman H Shugart Dean L Urban |
| |
| Institution: | (1) National Center for Atmospheric Research, P.O. Box 3000, 80307 Boulder, CO, USA;(2) Department of Environmental Sciences, University of Virginia, 22903 Charlottesville, Va., USA |
| |
| Abstract: | A gap model of environmental processes and vegetation patterns in boreal forests was used to examine the sensitivity of permafrost and permafrostfree forests in interior Alaska to air temperature and precipitation changes. These analyses indicated that in the uplands of interior Alaska, the effect of climatic warming on the ecology of boreal forests may not be so much a direct response to increased air temperature as it may be a response to the increased potential evapotranspiration demands that will accompany climatic warmings. On poorlydrained north slopes with permafrost, the drier forest floor reduced the flux of heat into the soil profile. This was offset by increased fire severity, which by removing greater amounts of the forest floor increased the depth of soil thawing and converted the cold black spruce forests to warmer mixed hardwood-spruce forests. On well-drained south slopes, the increased potential water loss reduced available soil moisture, converting these mesic sites to dry aspen forests, or if too dry to steppe-like vegetation. Increases in precipitation offset the effects of increased potential evapotranspiration demands and mitigated these forest changes. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
