Study On The Relationship Between The Main Factors And Its Function Of Water Conservation In Larix Principis-rupprechtii Mayr. Plantation Forest In Northern Hebei Mountain

Larix principis-rupprechtii Mayr is the most widely distributed in northern hebeimountain and volume up and the most main forest ecological species with the largestforest cover. This article start from the main factors of Larix principis-rupprechtii Mayrplantation forest, studys of main factors and the function of water conservation relations.Establish a database,using a multiple stepwise regression analysis to establish regressionmodel with five function of water conservation index(canopy interception rate, litter layermaximum water holding capacity, litter layer effective water capacity, soil layer maximumwater holding capacity, soil layer effective water capacity) and three stand factorindexes(crown density, the average tree height, soil layer effective water capacity). Larixprincipis-rupprechtii Mayr plantation forest of different forest age different density staticholding water capacity are studied, to explore the stand density effect on waterconservation ability, to further prepare the water-holding capacity of Larixprincipis-rupprechtii Mayr plantation density control diagram, Provide the data referenceand theoretical basis for Larix principis-rupprechtii Mayr in northern hebei mountain themanagement of water conservation forests management. Main conclusions are as follows:（1）In turn five function of water conservation index(canopy interception rate, litterlayer maximum water holding capacity, litter layer effective water capacity, soil layermaximum water holding capacity, soil layer effective water capacity) and three stand factorindexes(crown density, the average tree height, soil layer effective water capacity)respectively set up regression model after validation shows that: All the regression modelis at a significant level α=0.05significant conclusions are preliminary think five regressionmodel is reliable. In the process of regression simulation of all five groups, crown densityof regression equation was introduced5times, eliminate0times, Average diameter atbreast height was introduced4times, eliminate1times.(2) Indicators of five water conservation function(canopy interception rate, litter layermaximum water holding capacity, litter layer effective water capacity, soil layer maximumwater holding capacity, soil layer effective water capacity) and three stand factor indexes(crown density, the average tree height, the average diameter at breast height)regressionshows that crown density, the average tree height, the average diameter at breast height effect on the function of water conservation index was more significant,it is a linearpositive correlation. In terms of significance, for canopy interception rate, crown density isgreater than the average tree height, the average tree height is greater than the averagediameter at breast height; for stand the static holding water capacity, the average treeheight is greater than the average diameter at breast height, the average diameter at breastheight is greater than crown density.(3) Stand density and the stand static water-holding ability had no obvious linearrelationship, Along with the stand density increase, Larix principis-rupprechtii Mayr. Litterlayer and soil layer capacity showed a trend of first increased after decreased. When thelitter layer and soil layer water-holding ability achieves maximum, the best managementdensity of Larix principis-rupprechtii Mayr. plantation of different forest age:20a is2500n/hm2,30a is1800n/hm2,40a is1000n/hm2,50a is800n/hm2.(4) Optimum density of20a Larix principis-rupprechtii Mayr. plantation is2500plants/ha, the density can be used as Larix principis-rupprechtii Mayr. plantation at the beginning of the planting density. Larix principis-rupprechtii Mayr. belongs to long-lived tree species, In the study area of site environment to foster water source conservation forests, densityshould be controlled in800~1000plants per hectare in stand mature stage.(5)Through establishing model of relationship between equal tree height, equal diameter, maximal density, natural thinning line, volume and water content,it could prepare the water conservation function of different forest stand density control diagram. The water conservation function density control diagram of Larix principis-rupprechtii Mayr. is used to plantation forest Production estimates, resource investigation, forest thinning ect, it is of great significance to the production practice and regulating the function of water conservation forest, provide a new approach for Larix principis-rupprechtii Mayr.plantation management.