Light Characteristics And Species Association Of The Dominant Tree Species In Western Hunan Province And Its Forest Management Inspiration

Mixed-species forest management has been receiving increasing attention due to the diverse ecological and economic benefits.Afforestation with multiple tree species,promoting mixed species through natural regeneration and the transformation of planted monocultures to mixed stands are the main focus of mixed-species forest management.The optimal species configuration is of great importance to such transformations,as well as to the restoration of degraded secondary natural forests.The measurement of species association facilitates a comprehensive understanding of community structure and function in the forest.In turn,the association of the tree species in a given area can be a measure for species configuration.However,little is known about this species association in natural forests in the western Hunan Province,China.In this study,the light characteristics,economic value and species association between dominant tree species(including sapling and adult trees)was investigated in an old-growth forest in Huitong County,Hunan Province.Based on the results,we propose the selection of native tree species and the optimal species configuration under different forestation target,to support the establishment of mixed-species plantations,transformation of monocultures,and the enrichment planting in degraded secondary natural forests.Based on the above research,we analyzed the forestry characteristics of the Pinus massoniana degraded secondary forest in Cili County,Hunan Province.According to the forestry characteristics and social demand,we designed the forest development type,which provide an important basis for the sustainable management of degraded secondary forests in Western Hunan Province.The result showed that:(1)There were abundant species diversity in the natural old-growth forest,and Castanopsis fargesii was the most dominant tree species in the forest.The light characteristics of the dominant tree species are determined as follows:shade-tolerant tree species:Meliosma rigida,Cyclobalanopsis glauca,Antidesma japonicum;opportunity tree species:Castanopsis fargesii,Machilus pauhoi,Lithocarpus glaber,Vernicia Montana;shade-intolerent tree species:Triadica cochinchinensis,Engelhardia roxburghiana,Litsea mollis.The economic categories are divided as follows:the prime economic category:Machilus pauhoi;the first economic category:the secondary economic category:Castanopsis fargesii,Cyclobalanopsis glauca,Lithocarpus glaber;the tertiary economic category:Engelhardia roxburghiana,Vernicia Montana;the quaternary economic category:Meliosma rigida,Triadica cochinchinensis,Antidesma japonicum,Litsea mollis.(2)There is a significant overall positive species association in the natural old-growth forest,indicating that the forest is in a relatively stable state in terms of its structure and species composition.The result of species association showed that there was little difference between the number of pairs with positive associations and negative associations.The species pairs that exhibited significant associations according to the?~2 test has almost reached a significant level by the association coefficient,the Dice index,and Spearman's rank correlation coefficient,and the result of?~2 test has the highest correlation with the Spearman rank correlation coefficient.(3)In forest management,the light characteristics and economic value of tree species can be used to guide the selection of tree species under different site conditions and forestation target;the species associations between adult trees can be used to guide the mixed configuration of forestation;the species associations between saplings can be used to guide saplings configuration during enrichment plantings;the species associations between saplings and adult trees can be used to guide the selection of saplings tree species under the nearby adult tree.(4)According to the result of tree species characteristics and species association in natural old-growth forest,and the forestry characteristics and social demand of the degraded secondary forest,we designed the forest development type.In this type,the forest development goals are environmental protection and wood production,the target tree species of the main forest layer are Pinus massoniana,Machilus pauhoi,Cyclobalanopsis glauca and Castanopsis fargesii,and the timber of Pinus massoniana,Machilus pauhoi,Cyclobalanopsis glauca are the main channels of wood production.