Forest Multi-objective Planning For Natural Secondary Forest In Mao’er Mountain

Natural secondary forest with the important function in water and soil conservation,balance of nature maintainace is the main component of forest resource in our country.However,most of the natural secondary forest in our country showed worse performance in structure,productivity and ecology function and most of the natural secondary forest has turned into the forest with low quality and low efficiency.Thus,the reasonable and scientific forest management strategies should be taken at present to make full use of heterogeneous space-time resources,improve the productivity of forest land,maintain the long-term stability and health of forest ecosystem and accelerate the positive evolution of forest.In this study,the data of 4 periods of forest resource class two survey(1983,1993,2004,2016)and 2 periods of fixed sample survey(2004,2016)from Mao’er Mountian was used.Based on the analysis of forest landscape pattern and biodiversity at present stage,a multi-objective forest landscape planning model with wood production and tree species diversity was constructed.The harvest volume and species diversity was simulated for the future 50 years.The main content of the present study was follows:(1)In terms of spatial point pattern and correlation of forest landscape,the spatial pattern and correlation dynamics of forest landscape in Maoershan Experimental Forest Farm were quantitatively analyzed based on the O-ring univariate and bivariate statistical methods by using the data of two kinds of investigations in 1983,1993,2004 and 2016.From 1983 to 2016,the proportion of soft broad-leaved mixed forest in the study area decreased,the proportion of natural Mongolian oak forest landscape increased first and then decreased,while the proportion of hard broad-leaved mixed forest,larch plantation and Pinus sylvestris Plantation increased The spatial distribution types of soft broad-leaved mixed forest,hard broad-leaved mixed forest and natural Mongolian oak forest gradually change to random distribution or uniform distribution;Larch plantation shows random distribution or uniform distribution with the increase of scale range,and the scale range of uniform distribution gradually increases,and the scale range of random distribution gradually decreases;although the scale of aggregation and distribution of mongolian pine plantation also concentrates on small In the scale range,but the distribution range is increasing significantly.(2)In terms of biodiversity of different types of natural secondary forest in Maoershan,the relationship among the diversity indexes of herbs in soft broad mixed forest,hard broad mixed forest,larch plantation and mongolian pine plantation is hard broad mixed forest>soft broad mixed forest>larch plantation>oak natural forest>mongolian pine plantation;the relationship between the shrub diversity indexes of different types of forest is hard broad mixed forest>Soft broad mixed forest>natural oak forest>larch plantation>Pinus sylvestris Plantation.The diversity index of herbage and shrub in the mixed forest was the highest.In 1983,the tree species diversity indexes of soft broad mixed forest,hard broad mixed forest,larch artificial forest,mongolian pine artificial forest and oak natural forest were 1.3774,1.3057,0.0459,0.0414 and 0.5118 respectively,with significant differences among different forest types(P<0.05);in 1993,they were 1.3176,1.4260,0.0401,0.0408 and 0.6681 respectively,with significant differences among different forest types(P<0.05).In 2004,it was 1.4183,1.3593,0.1131,0.2217 and 0.6827,respectively,with significant differences among forest classification types(P<0.05);in 2016,it was 0.4786,0.5079,0.1844,0.1899 and 0.5180,with significant differences among forest classification types(P<0.05).On the whole,the tree species diversity of soft broad-leaved mixed forest and hard broad-leaved mixed forest is higher than that of artificial forest,which is in line with the overall trend of forest succession.From 1983 to 2016,the species diversity of soft broad-leaved mixed forest and hard broad-leaved mixed forest showed a downward trend,while that of larch plantation and mongolian pine plantation showed an upward trend,while that of oak natural forest basically remained unchanged.(3)In the aspect of growth model construction,the prediction model of DBH growth rate and stand volume growth was established.The growth rate of DBH of larch plantation was the highest,and that of Pinus sylvestris Plantation was the highest in the early stage,then decreased rapidly,so as to maintain a lower growth rate.The DBH growth rate of the soft broad-leaved mixed forest was higher than that of the hard broad-leaved mixed forest at the initial stage.When the DBH reached 25cm,the growth rate of the hard broad-leaved mixed forest was faster.By fitting the volume growth of each forest type,the Compertz equation was selected as the optimal basic model to simulate the volume growth per hectare of soft broad mixed forest,hard broad mixed forest,oak natural forest and larch plantation.(4)Multi objective forest landscape planning and simulation.Aiming at the balance of wood harvest and tree species diversity in the 50 year planning cycle(5 years in stages)of natural secondary forest in Maoershan area,a multi-objective forest landscape planning prediction model based on the effect function theory is constructed,the changes of wood production and tree diversity in the planning period are simulated,and the effect of forest management scheme is evaluated.In the planning period,the total wood harvest of five forest types,i.e.soft broad mixed forest,hard broad mixed forest,larch plantation,mongolian pine plantation and oak natural forest,can achieve the set target value.The tree species diversity of each forest type basically shows an upward trend in the planning period,and the spatial pattern of each landscape type tends to random distribution or uniform distribution Cloth.Reasonable forest management measures can improve the tree species diversity structure of forest ecosystem.On the basis of traditional wood production as the main management mode,the management measures that take into account the biodiversity of forest ecosystem play an important role in accelerating the positive succession of forest ecosystem.