The Impact Of Different Management Measures On Effcetcient Performance Of Larix Principis-rupprechtii Plantation

In order to explore the response of different management measures on forest stand.This study studied the quantitative response of three different management measures,i.e.close-to-natural management,lower-level thinning and comprehensive thinning,to stand structure,tree growth,plant diversity under forest and litter layer characteristics in Menglian Forest Farm of Mulan Forest Administration.The main conclusions are summarized as follows:In DBH structure,the three stands all conformed to normal distribution,but the skewness kurtosis of distribution curve was different.The skewness of the close-to-natural management,low-level thinning and comprehensive thinning normal distribution curve are:-0.27,-0.24 0.21.And the kurtosis was-0.71,-0.54and-0.61,respectively.Form the aspect of tree height structure,the three forest types all conformed to normal distribution,but the skewness and kurtosis of distribution curve were different.The skewness of the close-to-natural management,the lower layer thinning,and the comprehensive thinning normal distribution curve are:-0.05,-0.05,and 0.14,respectively;the kurtosis is-0.90,-0.66,-0.70,respectively.The growth ofLarix principis-rupprechtii forest under different management measures has obvious differences.By analyzing the growth of DBH,tree height and volume,it is found that the close-to-natural management stand has obvious advantages;the DBH,tree height and volume of close-to-natural management stand,under-layer thinning stand and comprehensive thinning stand in 2013 are not significantly different,but near 2017.The DBH growth of close-to-natural management stands is 1.25 cm,that of lower thinning stands is 1.05 cm,and that of comprehensive thinning stands is 0.77 cm.With the increase of time,the gap increases gradually,and the trend of height growth and volume growth is consistent with that of DBH growth.Species richness and biodiversity were highest in close-to-natural stand.The index of richness of the herb layer in the close-to-natural management forest,the integrated thinning forest,and the lower thinning forest were 0.3103,0.2875,and 0.2307,respectively,the species richness index of the shrub layer under the forest was 0.1496,0.1176,and 0.0822,respectively.These indicates that the species under the forest under the close-to-natural management stand were more abundant.Simpson index,Shannon-Wiener index and Peilou evenness index of understory herbaceous layer and shrub layer were compared as follows:close-to-natural management stand>comprehensive thinning stand>lower thinning stand.It could be seen that close-to-natural management stand was the most uniform and complex among three different stands.Litter reserves,water holding capacity,water absorption rate and interception were the highest in the close-to-natural management stand.The total storage capacity of the close-to-natural stand,the comprehensive thinning stand and lower layer thinning were25.68 t/hm~2,21.1 t/hm~2,20.64t/hm~2,respectively,and the maximum water holding capacity of the semi-decomposition layer was 19.95t/hm~2,13.27t/hm~2,10.74t/hm~2respectively.The maximum water holding capacity of the undecomposed layer was:14.75t/hm~2,11.29t/hm~2,10.23t/hm~2.The effective storage capacity of the undecomposed layer was:40.49t/hm~2,29.15t/hm~2,and 23.9t/hm~2,respectively.The effective storage capacity of the semi-decomposed layer was 54.47t/hm~2,43.24t/hm~2 and 25.16t/hm~2,respectively.The comparison of water absorption rate of litter layer was as follows:close-to-natural management forest stand>comprehensive thinning forest stand>lower layer thinning forest stand.On the whole,Larix principis-rupprechtii forest with three different management measures had the best water-holding performance close-to-natural management stand,and the close-to-natural management measures could effectively improve the water storage and water conservation capacity under the forest and improve the ecological benefit of the forest land.The management effect of Larix gmelinii stands under three different management measures was comprehensively evaluated by using the method of entropy weight.Close-to-natural management was the best,comprehensive thinning was the second,and lower thinning was the lowest.Close-to-nature management is better than the other two forests,so as far as Mulan Weichang State-owned Forest Farm Forest Administration is concerned,it is better to choose close-to-nature management.