Simulating the effects of forestry classified management on forest biomass in Xiao Xing'an Mountains

Abstract

Forest biomass is the largest carbon pool among terrestrial ecosystems, which plays an important role in mitigating global climate change through sequestrating carbon dioxide and increasing forested area and biomass. However, the disturbances such as climate change, timber harvesting and fire would affect forest biomass, therefore recently, an increasing attention rises on research of a wide range of disturbances that alter forest biomass and species composition. The forested area of China undergone intensive over-logging until 1998, to recover the forest structure and biomass from the past over-logged state, the government implemented forestry classified management. To reveal the effects of the forest management strategy, especially the timber harvesting on the forest and species biomass, the forest and main tree species biomass were simulated by LANDIS 7.0 PRO in the Xiao Xing' an Mountains in northeastern China, which is one of the three largest forested areas in China and the ecotone between temperate and boreal forest. LANDIS 7.0 PRO is the latest version of LANDIS (a spatially explicit model of forest landscape disturbance, management, and succession), which could simulate the dynamics of forest biomass at landscape scale. The study area covers 1.476×105hm2of forested landscape, and its forest dynamic and biomass were simulated over 200 years with the current forest management and no-harvesting scenarios. The main results show that:(1) The forest biomass in the no-harvesting scenario would increase with the simulation years from 93.6 t/hm2, and reach a maximum 258 t/hm2 approximately at next 90 year, and then fluctuate with an average 245 t/hm2, and the potential biomass for this region is about 258 t/hm2; (2) In next 100 years, with the comparison of no-harvesting scenario, the current harvesting scenario significantly decreases the forest biomass, and the maximum and mean forest biomass decline by 21.4 t/hm2and 14.7 t/hm2, respectively. But after the next 100 years, current harvesting does not significantly decrease the forest biomass, anyhow the forest biomass trend to decreasing by 2.6 t/hm2 averagely; (3) The current harvesting scenario increases the percentages of Korean pine and Amur linden, their biomass increases by 9.0 t/hm2(56%) and 0.53 t/hm2(15%), respectively under the comparison of no-harvesting scenario; (4) The current harvesting scenario affects highly the biomass of deciduous trees including ribbed birch, Black elm, white birch and wild poplar than the coniferous species including the spruces and Kingan fir which are allowed to be logged; (5)The forestry classified management can maintain the original forest structure like species composition, and promote the protected tree species growth and biomass. In addition, our results would be a good evaluation of current forest management strategy and a valuable guide for establishing a new forest management strategy in future.