Effects Of Logging Interference On Ecological Function Of Mixed Conifer-Broadleaf Forest At Jiaohe In Jilin Province,Northeastern China

As the main body of terrestrial ecosystem,forest ecosystem plays an extremely important role in the earth ecosystem.It can provide people with wood,forest by-products and so on,and provide economic functions.Under the new situation,logging not only requires wood production and pursues economic value,but also pays attention to the change of ecological function such as carbon sequestration and oxygen release,climate regulation,soil and water conservation,and consider the ecological benefits of forest.In this paper,taking the mixed conifer-broadleaf forest at Jiaohe in Jilin Province,northeastern China as the research object,method of combining field observation with computer simulation,and uses the forest optimization simulation model FSOS to explore the short-term and long-term effects of four kinds of tending felling?50%,35%,15%,0?on forest ecological function.Through the FSOS model,three kinds of forest management plans were formulated,and the expected effects of each plan were compared,so as to determine the forest management plan with the best comprehensive benefits.In order to provide some suggestions and countermeasures for the management of mixed conifer-broadleaf forest in the future,and make up for the deficiency of our country in multi-objective management decision.The results show that:?1?In view of the short-term effects of harvesting on forest ecological function,the changes of forest volume,forest community structure and tree species structure have a great influence on forest ecological function.The influence of these factors should be paid attention to first when cutting,and the factors of vegetation cover and tree height,although the influence is small,can not be ignored.?2?Felling has an effect on the rate of accumulation and growth in the forest,which will last for a long time,and the greater the intensity of felling,the longer the affected time.In the short term,the growth rate of accumulation increases first and then decreases with the increase of tending felling,It”s shown that tending felling 15%?8.24%?>control?8.19%?>tending felling 35%?6.89%?>tending felling50%?6.71%?,but the effect of cutting on the growth of stand height is not significant.?3?In the short term?within 30 years?,no harvesting can make more CO₂fixed in the forest.But in the long run?30 years later?,harvesting can fix more carbon and effectively mitigate the greenhouse effect.Therefore,in order to obtain the maximum carbon storage benefits,the focus should be on long-term forest management rather than short-term management,and in forest management,as much as possible to maintain the amount of carbon in the forest and its products and extend the life of wood products.?4?The greater the tending felling,the longer the restoration time of forest ecological function.it takes 5-10 years to restore the forest after 15%tending felling,10-15 years to restore the 35%tending felling,and the longest recovery time of 50%tending felling takes 15-20 years.After medium and low intensity harvesting,the forest can show better growth potential,and the diversity of tree layer,shrub layer and vegetation layer has been improved.Although the cutting scheme based on 15%tending felling can obtain higher ecological benefits,the proportion of over-maturing forest is higher in the later stage of simulation,accounting for about 25%,which affects the forest growth rate and collection.The logging scheme based on 50%tending felling will reduce the stability of the forest ecosystem,the age structure of forest is unreasonable,the proportion of middle-aged forest is too much and fluctuate around 50%,which affects the function of ecosystem and is not conducive to sustainable management.The harvesting plan based on moderate harvesting makes the forest have a more reasonable age structure,which can not only obtain higher ecological benefits,but also make better use of wood resources,obtain more economic benefits,the average annual profit is about 600,000 yuan and maximize the comprehensive forest benefits.Comprehensive consideration,for Jilin Jiaohe broad-leaved mixed forest,35%tending felling scheme is the most reasonable,once every 20 years,tending felling should be about 35%.