天然油松次生林天然更新新法，可使次年每公顷天然更新幼树达７５００株以上，三年后每公顷保留６７５０株以上，且颜色正常，长势良好。现将其主要技术介绍如下：一、选择结实年（丰年）进行抚育间伐。在天然油松次生林结实较多的年份（丰年），对近熟、成熟和没有发展前... The natural regeneration of natural secondary forest of Pinus tabulaeformis will enable more than 7,500 saplings to be regenerated naturally per hectare in the following year and over 6,750 sapings per hectare after three years with normal color and good growth. Now its main technical introduction is as follows: First, select the strong year (harvest year) tending thinning. In the natural oil pine secondary forest firmer more years (bumper year), almost ripe, mature and without pre-development ...