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世界上栽培的杨树90％都属于黑杨派,这是与它生长期长、生长快、抗性强、材质好、短期内就可提供大量木材等优点分不开的。目前黑杨派仅在北美还保留有经济价值的天然林分。在欧洲和亚洲都是小面积分散各地。据说在我国新疆还有天然林分布,但经济价值不大。然而黑杨派的人工林则恰恰相反,它在世界上很多地区具有重要经济价值。如意大利的杨树造林面积达40万公顷,虽只占农林用地的3％,但每年能生产400万立方米木材,占全国工业用材的三分之一;在欧洲北纬55°以南、西到黑海这一片地区有100多万公顷人工林和成行栽植的黑杨;在近东北纬30°以北至阿富汗和巴基斯坦有20万公顷;在日本、新西兰、澳大利亚、南非和马达加斯加也有大面积的人工林;我国从1975年引种以来,有很大发展,特别在平原缺材地区,得到群众喜爱,据不完全统计已有5万多公顷(近80万亩),年龄最大的人工林已九年生,最大胸径48厘米,最大树高30米。为了统一计算其立木材积标准,研究材积生长过程,本文将报道黑杨派中四个无性系立木材积表的编制。
Ninety percent of poplar cultivated in the world belong to the black poplar genus, which is inseparable from its long growing period, fast growth, strong resistance, good material, and the ability to provide large quantities of wood in a short period of time. At present, Black Pops only retain natural economic value in North America. Small areas are scattered throughout Europe and Asia. It is said that there is still a natural forest in Xinjiang of our country, but the economic value is not big. However, on the contrary, black plantation plantations have important economic value in many areas of the world. For example, poplar trees in Italy have a planting area of 400,000 hectares, accounting for only 3% of the land used for agriculture and forestry, but can produce 4 million cubic meters of timber each year, accounting for one-third of the national industrial timber. In Europe, There are more than 1 million hectares of plantations and black poplars planted in the area to the Black Sea; 200,000 hectares in the near northeast latitude 30 ° to Afghanistan and Pakistan; and a large area of labor in Japan, New Zealand, Australia, South Africa and Madagascar Since the introduction in 1975, our country has greatly developed, especially in the plain areas, get the masses favorite, according to incomplete statistics, more than 50,000 hectares (nearly 800000 acres), the oldest plantations have been nine years , The maximum diameter of 48 cm, the maximum tree height of 30 meters. In order to unify the calculation of the standing timber volume standard and the study of the volume growth process, this paper will report the establishment of four clonal stand volumes in the black poplar.