论文部分内容阅读
目前的许多南方松林都是1930～1950年在荒废的农田上经天然播种和人工栽植所形成的。幼林在很少受到管理,甚至不管理的情况下迅速生长。由于林分的郁闭度和生产力的下降,害虫问题已逐渐发展且趋于严
Many of the current southern pine forests were formed from natural sowing and planting on abandoned farmland from 1930 to 1950. Young forests grow rapidly with little or no management. Pest problems have evolved and tended to be harsh due to canopy standoff and productivity decline