The long-term effects of fire suppression and reforestation on a forest landscape in Northeastern China after a catastrophic wildfire

Abstract

This study used the LANDIS model to evaluate the effects of fire suppression and reforestation on fire dynamics, species abundance, and age structure of two main species (larch ( Larix gmelinii) and white birch ( Betula platyphylla)) in Tuqiang Forest Bureau on the northern slopes of Great Hing’an Mountains after a catastrophic fire in 1987. Three fire regimes (no fire, low fire suppression, and current high fire suppression) and two planting strategies (no planting and larch planting) were compared in a 3 × 2 factorial design using 10 replicated simulations per treatment combination over a 300-year period. The results showed that compared with low fire suppression scenario, high fire suppression would create a landscape with lower-frequency and higher-intensity fire, whereas reforestation had no significant influence on cumulative area damaged by fire in the study landscape. High fire suppression positively influenced larch abundance, but negatively influenced white birch abundance. The results showed under high fire suppression scenario, over-mature larch forests had greater abundance than that under low fire suppression scenario, whereas younger cohorts show an opposite pattern to the old age cohorts. Under the “larch planting” scenario, larch at each age class had a greater abundance than that under the “no planting” scenario. Younger cohorts of white birch under the high fire suppression scenario had a lower abundance than that under the low fire suppression. The results also showed that reforestation positively influenced larch abundance, but negatively influenced white birch abundance. Compared with the “no planting” scenario, it would take 30–40 years longer for larch abundance to return to pre-fire abundance in 1987 than under the “larch planting” scenario. Also, under the “larch planting” scenario, larch always had an obviously greater abundance than that under the “no planting” scenario in the 300-year simulation. Therefore, reforestation would benefit larch recovery, which could last for more than 300 years. These results have important implications for forest managers to design sound forest restoration projects for landscapes affected by large infrequent disturbances by fire. In particular, the results suggest that high fire suppression and reforestation would be appropriate in the study landscape, based on the purpose of local government to increase the abundance of coniferous forests as soon as possible.