论文部分内容阅读
地位区分的方法根据树高,地位有下面2种区分方法。 (1) 相对的树高地位平均高为年令的函数,把它分为上、中、下三个等级或划为Ⅰ、Ⅱ、Ⅲ级区分地位。我国的收获表多采用这种方法。 (2)绝对的树高地位依一定基准年令的林分平均高或者林分上层高区分地位者,北美等国多用此法。美国一般以50年或100年为基准年令。基准年令的树高用20、30、40、50英尺等表示即以20英尺为间隔,把那个树高即乏。、30、连。、50……等叫做地位指数。换言它,所谓地位指数,也就是主林木达到基准年令时的树高值。基准年令根据轮伐期的长短或伐期令适当的选择它。用林令和树高的关系表示的地位曲线象(1)那样的
The method of distinguishing the status According to the height of the tree, the status has the following two kinds of distinguishing methods. (1) The relative average height of tree height is a function of the year, which is divided into upper, middle and lower ranks or classified as Ⅰ, Ⅱ and Ⅲ. Most of our harvest tables use this method. (2) The absolute height of the tree According to a certain reference year’s average high stand or high above the stand, North America and other countries use this method. The United States generally takes 50 years or 100 years as its base year. The height of the base year is 20, 20, 40, 50 feet and so on, ie 20 feet apart. , 30, even. , 50 ...... And so called status index. In other words, the so-called status index, which is the tree height when the main tree reaches the base year. The base year chooses it appropriately according to the length of the rotation or the lapse order. The status curve represented by the relationship between the forest tree and the tree height is like (1)