油松是陕北黄土高原的乡土树种,至今在黄龙山、乔山等山区仍然有天然分布。解放后作为主要造林树种,营造了大面积的人工林,早期人工林现已郁闭,长势良好。为更好地培育油松人工林,以期达到速生丰产、保持水土、改善农业生产条件的目的,我们对密度与油松生长的关系作了调查,取得了一些资料。现整理如下,以供参考。一、调查地区的自然概况调查地区位于宜川县南部的仕望河以南、黄龙山北麓,属铁龙湾林场管区。本区属华北气候带,为半湿润地区。春 Pinus tabulaeformis is a native tree species of the Loess Plateau in northern Shaanxi. So far, there are still natural distributions in Huanglongshan, Qiaoshan and other mountainous areas. After the liberation as a major afforestation tree species, creating a large area of ​​plantations, early plantation is now closed, growing well. In order to better cultivate Pinus tabulaeformis plantation, with the purpose of achieving fast-growing and high-yielding, soil and water conservation, and improving agricultural production conditions, we investigated the relationship between density and Pinus tabulaeformis and obtained some data. Now collated as follows for reference. First, the survey of the natural landscape Survey area is located south of Shichuan River in Yichuan County, north of Huanglong Mountain, is a ferron Bay Forest Management District. The area belongs to the North China climate zone, semi-humid areas. spring