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热带森林通常林下植物茂密,层次多,乔木多板根,不便于采用常规的抽样法测定立木蓄积。有人建议用粗放的而在许多情况下花钱多的方法来调查这些森林,其法之一就是在乌干达天然林里使用的“立木制图法”。但是,立木制图法有很大的局限性。因此,在估测热带森林蓄积时,建议采用3P抽样法来提高立木制图技术的效率。热带森林的特征是种类多,树龄不一。少数树种如红木,价值很高,但大多数树种则被列为当前不合用。由于林下植物茂密、层次繁多,乔木多板根,攀援植物繁茂,不便用传统的调查法测定立木的蓄积和生长。经营者常采用粗放而在许多情况下花钱多的方法来估测目的树种的立木蓄积。例如在乌干达使用的Taylor(1947)创建的所谓“立木制图法”就是这种方法之一。
Tropical forests are usually dense under the forest plants, multi-level, multi-rooted tree, not easy to use conventional sampling method to determine the accumulation of standing wood. One suggestion was to survey these forests extensively and in many cases costly methods, one of which is the “legislation on cartography” used in the natural forests of Uganda. However, legislation on cartography has great limitations. Therefore, in the estimation of tropical forest stockpiles, 3P sampling is recommended to improve the efficiency of cartography. Tropical forests are characterized by many different ages. A few species such as mahogany are of high value, but most species are listed as currently unused. As the plant under the lush forest, a wide range of multi-rooted trees, climbing lush plants, inconvenience to determine the accumulation and growth of standing wood by traditional investigation method. Managers often use extensive and, in many cases, expensive methods to estimate the stockpile of the target species. One such method, for example, is the so-called “cartography” created by Taylor (1947) used in Uganda.