Simulating the effects of climate change on the carbon balance of North American high-latitude forests
Global Change Biology
The large magnitude of predicted warming at high latitudes and the potential feed- back of ecosystems to atmospheric CO2 concentrations make it important to quantify both warming and its effects on high-latitude carbon balance. We analysed long-term, daily surface meteorological records for 13 sites in Alaska and north-western Canada and an 82-y record of river ice breakup date for the Tanana River in interior Alaska. We found increases in winter and spring temperature extrema for all sites, with the greatest increases in spring minimum temperature, average 0.47 °C per 10 y, and a 0.7- day per 10 y advance in ice breakup on the Tanana River. We used the climate records to drive an ecosystem process model, BIOME_BGC, to simulate the effects of climate change on the carbon and water balances of boreal forest ecosystems. The growing season has lengthened by an average of 2.6days per 10y with an advance in average leaf onset date of 1.10days per 10y. This advance in the start of the active growing season correlates positively with progressively earlier ice breakup on the Tanana River in interior Alaska. The advance in the start of the growing season resulted in a 20% increase in net primary production for both aspen (Populus tremuloides) and white spruce (Picea glauca) stands. Aspen had a greater mean increase in maintenance respiration than spruce, whereas spruce had a greater mean increase in evapotranspira- tion. Average decomposition rates also increased for both species. Both net primary production and decomposition are enhanced in our simulations, suggesting that pro- ductive forest types may not experience a signi®cant shift in net carbon ̄ux as a result of climate warming.
Keyser, A.R.; Kimball, J.S.; Nemani, R.R.; and Running, S.W., "Simulating the effects of climate change on the carbon balance of North American high-latitude forests" (2000). Aspen Bibliography. Paper 836.