森林植被地带分布规律主要由水热两个气象因素所决定,因此,研究榆林地区的林业生产不能不涉及到水热平衡问题。榆林地区属于半干旱大陆性季风气候,这里的植被表现出强烈的草原特点。过去由于忽视了这一特点,在林业生产中重乔轻灌,过于密植,消耗了大量的水分资源,致使林木长成无利用价值的 The distribution law of forest vegetation zone is mainly determined by two meteorological factors, such as hydrothermal. Therefore, the study of forestry production in Yulin area can not but involve the issue of water-heat balance. Yulin region belongs to the semi-arid continental monsoon climate, where vegetation shows strong prairie characteristics. In the past, due to the neglect of this feature, heavy forestry and light irrigation in the forestry production were too dense and consumed a large amount of water resources, resulting in the growth of forest trees without utilization value