Effects of Density Control on the Stand Features of Cunninghamia lanceolata Plantation

A Cunninghamia lanceolata plantation of Hongya Forest Farm was selected as an object to research the stand features under density control from three respects of forest growth, species diversity and stand structure. The results showed that low density management was conducive to accelerating the growth of DBH,tree height,and wood vulume,which could also make the trunk fuller. However, low density management reduced the natural pruning capacity of the stand. Appropriate density management(750 plants·hm^-2) could increase the species richness of the shrub and herb and layers,while the high density(12 000 plants·hm^-2) or low density (550 plants·hm^-2) reduced the species richness of the shrub and herb and layers.The species diversity index and evenness index of shrubs and herbs in low density stand were higher than those in high density stand.The low density management made the community complexity and the species distribution evenness better.With the increase of forest density, the proportion of large-diameter plants in the stand decreased gradually.Reasonable density(750 plants·hm^-2) was conducive to the growth of tree heigght.Low management density was beneficial to cultivating large-diameter trees, while high management density was beneficial to cultivating medium and small-diameter wood plants.