Research Status and Trend on Plantation Density Control Techniques in Arid and Semi-arid Regions

This article reviewed the research status of the plantation density control techniques based on domestic literature,and discussed the technical issues on plantation density control in the arid and semi-arid region.Nowadays,more studies focused on modeling study,but with less mechanism;more on the pure plantation with similar ages and site conditions,rather than mixed forests;and more on the fast-growing timber plantation in South,but less on the plantation in arid and semi-arid regions.It was imperative to study the density control techniques which focused on the water factors,such as the techniques of water production function in the arid and semi-arid regions.The traditional density control techniques aimed to attain the highest production by relating the system density and production.The density control techniques based on water production function set the point of entry with the water factors,complied with the principle of water supporting capacity.The timely density control based on the amount of available water in the plantation ecosystem could ensure the best balance among the economic,ecological and social benefits of forests.It would be also beneficial to avoid from or reduce the problems of soil degradation,soil drying and groundwater decreasing caused by improper afforestation,and more suitable for the density management of plantation in the arid and semi-arid region.