The Growth Characteristics And Water Conservation Features Of 13-Year-Old Michelia Macclurei Dandy Plantation In Gaofeng Forest Farm

The 13-year-old Michelia macclurei Dandy intensive farming plantation in Gaofeng Forest Farm were carried to investigate its growth regularity, biomass and biomass productivity, water conservation features of soil layer and vegetation layer, which can reveal further about the tree species characteristics of Michelia macclurei Dandy, and provide a scientific management and technical support, and provide a scientific reference for water conservation works on water loss and soil erosion area in our country. The results showed that:（1）Growth pattern:The average tree height of 13-year-old Michelia macclurei Dandy plantation was 14.39m, the average diameter at breast height （DBH） was 13.46cm, the average plant volume was 0.11835m3.（2）Biomass and biomass productivity:The total biomass of Michelia macclurei Dandy plantation ecosystem was 246.06 t·hm’2, the biomass of tree layer was 234.46t·hm^-2,the order of different tree layer organs was:tree trunk> root pocket> trunk bark> branch> leaf> thick root> middle root> thin root; the tree layer annual average net primary productivity was 18.04 t·hm^-2·a-1.（3）Soil bulk density and porosity:The average soil bulk density of Michelia macclurei Dandy on the soil layer of 0-20cm,20-40cm,40-60cm、60-100cm was 1.29 g·cm-3、1.36 g·cm-3、.42g·cm-3、1.46 g·cm-3, and the Soil total porosity was 46.66%,45.15%,42.09%, 44.00%, and the capillary porosity was 44.10%,40.62%,38.30%,41.42%.（4） Soil water storage capacity and permeation rate:The maximum water storage capacity of Michelia macclurei Dandy on the soil layer of 0-20cm、20-40cm、40-60cm、 60-100cm was 933.11 m3·hm^-2、903.09 m3·hm^-2,841.71 m3·hm^-2、1760.10 m3·hm^-2, and the final infiltration rate of every layer was 2.09 mm·min-1、0.73 mm-min-1、0.36 mm·min-1 0.21 mm-min-1, the initial infiltration rate was 5.95 mm·min-1、2.00 mm·min-1、1.10 mm·min-1、0.28 mm-min-1.（5） Water conservation features of tree layer:The natural moisture content of every organ of tree layer of Michelia macclurei Dandy was between 40.21%～68.66%. The water holding ratio of leaf was 27.33%, and the water holding capacity was 7.40 t-hm^-2; the water holding ratio of branch was 10.77%, and the water holding capacity was 3.35 t-hm^-2; the water holding ratio of trunk bark was 10.95%, and the water holding capacity was 3.58 t·hm"2.The order of water holding ratio was leaf>trunk bark>branch.（6） Water conservation features of ground layer and litter layer:The natural moisture content of under growth vegetation of Michelia macclurei Dandy plantation was 45.01%, and the natural moisture content of litter layer was 9.33%. The water holding ratio was 23.76’ and 139.14%, and the water holding capacity was 0.000742 t-hm^-2 and 17.78 t-hm^-2.（7） As a whole, water holding capacity of the whole ecosystem was 4470.12 t-hm^-2, tree layer、under growth vegetation and litter layern soil layer accounted for 0.32%、0.40%、 99.28%.