由于按树速生丰产和利用范围的逐步扩大,许多热带和亚热带少林缺材国家和地区,近几十年来,迅速引进桉树,发展桉树人工林。有的国家引进和发展桉树人工林,在短期内解决了无材或缺材问题,或者由缺材一跃而变成木材出口国家。目前,世界桉树人工林经营的集约水平不断提高,各种桉树林亩蓄积年增长普遍达一至二立方米,最高的超过三立方米。树高年增长二至三米,胸径年增长二至四厘米。不少国家桉树的轮伐期在十年左右。浆粕和纺织用材的轮伐期只有五至七年。桉树树种改良普遍受到重视。有些国家已经 In recent decades, eucalyptus trees have been rapidly introduced and eucalypt plantations have been developed in many tropical and subtropical forest-lacking countries and regions due to the rapid expansion of tree production and utilization. In some countries, the introduction and development of eucalyptus plantations has solved the problem of lack of materials or lack of materials in the short term, or it has become a timber exporter by leaps and bounds. At present, the intensive management of eucalypt plantations in the world has been continuously enhanced. The annual accumulation of eucalyptus forests has generally increased by one to two cubic meters per year and the highest is over three cubic meters. Trees grow 2-3 meters in height, with an annual increase in DBH of 2-4 cm. In many countries, the rotation period of eucalyptus is about ten years. Pulp and textile timber have a rotation of only five to seven years. The improvement of eucalyptus tree species is generally valued. Some countries already