Research On The Growth Competitive Ability Of Constructive Species In Karst Forest Of Plant Community

As an important content of ecology research,plant competition longs forever.In the karst area,the competition of plant species in the karst area used a competitive index to study widely between the intraspecific and interspecific relationships,but failed to better explain the plant growth characteristics,nutrient utilization characteristics,cost building characteristics and the growth competitiveness of plants during the competition process among plants,which seriously restricts the development of plant competition theory and forest management in karst area(especially species screening).Therefore,this paper takes the species(monkey camphor,hi tree,magnolia,light birch and bell leaves)in the typical secondary forest of karst area,and combines field experiment and indoor indicators to analyze(N),phosphorus(P)and potassium(K)nutrient contents and the cost of different tree species,the difference between the organs.When using AHP method to comprehensively evaluate the growth of five kinds of tree species growth ability,the main conclusions are as follows:(1)The biomass allocation characteristics of tree species in the typical secondary forest in the middle karst area of Guizhou were dry> shoot> leaf> root pocket> root;the aboveground biomass> underground biomass,rhizome ratio range was 0.11 ~ 0.44,mean 0.22.(2)Different light environment under different growth rate indicators are different.The diameter growth rate for isolated trees : Isolated Wood(5.01 mm / a)> Forest edge wood(4.82 mm / a)> forest wood(4.32 mm/a);the growth rate of tree height was as follows: forest wood(0.86 m / a)> Forest edge wood(0.83 m / a)> Isolated wood(0.75 m / a);The rate of biomass accumulation was as follows: the fastest of different tree species in isolated environment,monkey camphor and Magnolia as follows: forest edge wood> forest wood,light birch,Light birch,hi trees and leaves table: forest wood> forest edge wood.(3)The variation of leaf area in different canopy was obvious.In the forest environment,the upper layer was significantly lower than the lower layer,but the difference was not significant with the middle layer;the forest edge environment was not changed obviously;there was no significant difference between the different canopy in the isolated environment.(4)The caloric value of tree roots is significantly lower than that of leaves,shoots and stems.The calorific value of original broad-leaved forest species in Karst(16.71 ± 0.94 KJ / g)was lower than that of secondary forest broad-leaved forest(18.53 ± 0.77 KJ/ g).The cost buildings of different organs are realized as follows: leaf> shoot or stem> root;aboveground parts are more expensive to construct than to build the underground.Construction costs vary among different regions.(5)Based on the research on tree growth ability,nutrient utilization ability and capacity of cost building,the evaluation index system of tree species growth competitive ability was constructed.The AHP method was used to evaluate conclusively the growth ability of tree species.The results showed that under different light conditions,There are differences in the growth ability of tree species.On the whole level,the growth and competition ability of five kinds of tree species in karst secondary forest in Guizhou were from Magnolia(0.256),Light birch(0.236),Young leaves(0.226),Hi tree(0.210)and Monkey camphor(0.188).