Spatial simulation of forest succession under different fire disturbances and planting strategies in northern slopes of Great Xing'anling Mountains

The study tries to simulate forest dynamics over 300 years in Tuqiang Forest Bureau of the northern slopes of Great Xing'anling Mountains,which was damaged by a catastrophic fire in 1987. Nine scenarios were run by the LANDIS model under three fire conditions (no fire simulating, fire return interval of 150 years and fire return interval of 325 years) and three planting strategies(no planting; Larix gmelini planting and Pinus sylvestris var. mongolica planting). The authors examined the effects of each scenario on fire dynamics and area percentage, and age class of species. The results showed that the fire regime was characterized by higher frequency, lower intensity and larger burned areas at the fire return interval of 150 years than at fire return interval of 325 years. In addition, more burned areas were under reforestation than natural regeneration. Because of lower fire tolerance of P. sylvestris var. mongolica than L. gmelini, more forest stands were burned under the scenario planting P. sylvestris var. mongolica. Different fire return intervals can change the area percentage of the species, and have great effects on the species age class. Responses of most species to the changing fire return intervals were predictable based on their fire tolerance parameters, with fire-tolerant species most abundant in landscapes with frequent fire at short fire return interval, and fire-sensitive species most prevalent in landscapes with less fire at long fire return interval. But if the species have an ability to disperse seeds well and can successfully root in these disturbance-created openings, they would increase more quickly and the stand age was tended to be younger at short fire return interval than at long fire return interval. Planting strategies have great influence on species, especially those to be planted. The area percentage of P. sylvestris var. mongolica could not reach the prefire level in 1987 under natural regeneration. If we want to restore the area percentage of P. sylvestris var. mongolica to the prefire level in 1987, the strategies to plant this species is required.