Simulating the effects of reforestation on a large catastrophic fire burned landscape in Northeastern China

We use the LANDIS model to study the effects of planting intensity and spatial pattern of plantation on the abundance of three main species (larch (Larix gmelini), Mongolian Scotch pine (Pinus sylvestris var. Mongolica), and white birch (Betula platyphylla)) in the Tuqiang Forest Bureau on the northern slopes of Great Hing’an Mountains after a catastrophic fire in 1987. Four levels of planting intensity (covering 10%, 30%, 50%, and 70% of the severely burned area) and two spatial patterns of plantation (dispersed planting and aggregated planting) were compared in a 4 × 2 factorial design over a 300-year period. The results showed that increasing planting intensity positively influenced larch and Mongolian Scotch pine abundance, but negatively influenced white birch abundance. However, the increased degree of larch abundance with increasing planting intensity was significantly different between intensities. The difference in larch abundance between the 10% planting intensity scenario and the 30% planting intensity scenario was greater than that between the 50% planting intensity scenario and the 70% planting intensity scenario. However, the difference between 30% and 50% planting intensity scenarios was significantly low. Hence, given considerable labor input and economic costs, 30% planting intensity would be effective for forest recovery. In addition, dispersed planting showed more promising results on forest recovery than aggregated planting. However, the difference of larch abundance between dispersed planting and aggregated planting under intermediate planting intensity scenarios (30% and 50% planting intensity) was greater than that under a low planting intensity scenario and a high planting intensity scenario. Therefore, it is necessary to incorporate spatial pattern of plantation into planting practice, especially under an intermediate planting intensity scenario. These results have important implications for forest managers to design sound forest restoration projects for landscapes affected by large infrequent disturbances. In particular, the results suggest that the current planting strategy (50% planting intensity with aggregated planting) employed after the catastrophic fire in 1987 could not be optimum, and the dispersed planting strategy covering about 30% of the severely burned area would better stimulate forest recovery.