The Effect of Nitrogen Enrichment on the Carbon Sink in Coniferous Forests: Uncertainty and Sensitivity Analyses of Three Ecosystem Models |
| |
Authors: | Peter E. Levy Renate Wendler Marcel Van Oijen Melvin G. R. Cannell Peter Millard |
| |
Affiliation: | (1) Centre for Ecology and Hydrology, Bush Estate, Penicuik, EH26 0QB Midlothian, UK;(2) Macaulay Land Use Research Institute, Craigiebuckler, AB15 8QH Aberdeen, UK |
| |
Abstract: | Estimates of the global carbon sink induced by nitrogen enrichment range vary widely, from nearly zero to 2.3 Gt C year-1. It is necessary to reduce this uncertainty if we are to make accurate predictions of the future magnitude of the terrestrial carbon sink. Here, we present a Monte Carlo approach to uncertainty and sensitivity analysis of three ecosystem models, Century,BGCand Hybrid. These models were applied to a coniferous forest ecosystem in Sweden. The best estimate of the change in total carbon content of the ecosystem with the cumulative change in nitrogen deposition over 100 years, Ctotal/ Ndeposition was 20.1 kg C (kg N)-1 using the pooled mean, with a pooled standard deviation of 13.8 kg C (kg N)-1. Variability in parameters accounted for 92% of the total uncertainty in Ctotal/ Ndeposition, and only 8% was attributable to differences between models. The most sensitive parameters were those which controlled the allocation of assimilate between leaves, roots and stem. In particular, an increase in allocation to fine roots led to a large reduction in Ctotal/ Ndeposition in all models, because the fine roots have a very high turnover rate, and extra carbon allocated there is soon lost through mortality and decomposition. |
| |
Keywords: | carbon sequestration Monte Carlo simulation nitrogen Norway spruce parameterisation Picea abies sensitivity analysis uncertainty |
本文献已被 SpringerLink 等数据库收录! |
|