Adapting a patch model to simulate the sensitivity of Central-Canadian boreal ecosystems to climate variability

Aim To investigate effects of within-season and interannual climate variabi lity on the behaviour of boreal forest ecosystems as simulated by the FORSK A2 patch model. Location Eleven climate station locations distributed along a transect acro ss the boreal zone of central Canada. Methods FORSKA2's water balance submodel was modified to enable: it to bch; ive more realistically under a varying climate, Long-term actual monthly ti me-series of temperature and precipitation data were detrended and used to drive the modified model. Long-term monthly averages of the same detrended data were used to drive the unmodified model. Results Modifications created significant improvements when simulating spec ies composition at sites in boreal Canada. Simulated forest biomass values were slightly higher than those obtained from the unmodified model using av eraged climate records, hut resembled the observed distribution of vegetati on more closely. Main conclusions Modified FORSKA2 suggests that boreal forest composition a nd distribution may be more sensitive to changes in monthly rainfall data t han to changes in temperature, Climate variability affects seasonal water b alances and should be considered when using patch models to forecast vegeta tion dynamics during and following a period of climate transition. The modi fied model provided improved representation of the latitudinal trend in spa tially averaged biomass density in this region.