甘肃小陇山灌木林不同改造模式天然更新研究

用样方法,研究了小陇山林区5种典型灌木林地改造模式的乔木树种天然更新幼苗的密度和多样性。结果表明:5种灌木林地改造模式的乔木树种天然更新情况总体良好,小于50 cm高度级幼苗数量相对较少,大于50 cm高度级幼苗的存活率较高;5种改造模式天然更新树种以锐齿栎为主,其中,全面割灌改造日本落叶松(模式3)更新幼苗物种丰富度最高,全面割灌改造油松模式(模式2)天然更新树种丰富度最小;带状割灌改造模式(模式4和模式5)和全面割灌改造华山松模式(模式1)的更新树种多样性较高,各树种分配均匀,优势树种的集中性较低;改造树种华山松的天然更新能力较油松日本落叶松强,带状割灌改造模式更有利于华山松天然更新。

Study on Natural Regeneration of Different Shrub Forest Transformation Models on Xiaolongshan in Gansu

Natural regeneration is important on forest management and it's reflecting the trend of forest development. The quadrat method is used to study the natural regeneration density and species diversity of seedling trees under five different shrub forest transformation models on Xiaolongshan, the result show that natural regenerations under the five shrub forest transformation models are good, the number of seedling with the height class lower than 50 cm is relative less and the preserving rate of seedling with height class greater than 50 cm is higher; the dominant regeneration species is Quercus aliena for all of the five shrub forest transformation models. The natural regeneration tree species abundance of transformed Larix kaempferi stand with overall shrub cutting (Model 3) is the highest and that of transformed Pinus tabulaeformis stand with overall shrub cutting (Model 2) is the lowest; the tree species diversities of the transform models with zonal shrub cutting (Model 4 and Model 5) and transformed Pinus armandii stand with overall shrub cutting (Model 1) are higher, the distribution of tree species in stand was uniform and the concentration tendency was lower. The natural regeneration ability of Pinus armandii is stronger than that of Pinus tabulaeformis and Larix kaempferi and the transform model with zonal shrub cutting is beneficial to Pinus armandii's natural regeneration.