巴西桉树面积达到470万hm2,占人工林面积的83.93%,是巴西林业经济的大部分和国民经济的重要组成部分。科技是巴西桉树发展的翅膀,使生长量从1960年代的10 m3.hm-2.a-1大幅提高到目前的40 m3.hm-2.a-1水平,帮助巴西成为世界桉树人工林水平最先进的国家。巴西特别重视桉树的遗传改良,林纸公司都有自己的育种计划,不断生产新品系;目前,巴西各林业公司以巨桉×尾叶桉无性系为主,在生产一线使用的有5~8个巨尾桉无性系,储备的无性系更多一些。最小耕作法,使巴西桉树持续高产,其要点是必须保留采伐剩余物,拿走采伐剩余物5 a后的土壤分析表明N、P、K和Ca分别损失4%、13%、31%和5%,这将严重改变立地质量;整地必须严格控制扰土面积,在地势较平坦地区采用全机械＂深耕裂土＂方式整地,在丘陵区用小型手工机械挖暗穴整地方式或者人工用镐松土;造林采用小型手工机械栽植和施肥,这样可以减少扰土面积,但效果不减。机械化或小型机械化是桉树种植、经营和采伐的必由之路。白蚁和杂草严重影响桉树生长,必须严加控制。萌芽更新是巴西桉树人工林主要更新方式之一,与再造林相比,桉树萌芽更新有诸多优势,造林程序少、成本大幅降低;生长量方面,到7年生砍伐时,可能减产16%,利润却可增加21%。＂镶嵌式＂造林格局在巴西最典型,在河流、道路、小班分界、林道等地方要保留一定的次生林,以保护环境、隔离病虫害、美化生态以及防火等。对劳工的保护、尊重、提高劳动待遇是高质量完成各项造林、经营和采伐任务的根本保证。%There are 4.7 millions hm2 of eucalypt,83.93 % of total plantation in Brazil,which consists of the main forestry economy and important part of national economy.Science and technology are the key reasons for improving the MAI from 10 m3·hm-2·a-1 in 1960＇s to the current level of 40 m3·hm-2·a-1 and becoming the most advanced eucalypt management level in the world.The forestry companies paid special attention to tree breeding programs to constantly produce new hybrids and clones.The current eucalypt hybrid used by forestry companies is Eucalyptus grandis×E.urophylla,only 5～8 clones are used each company but more clones are stored up.The works for tillage must be minimised to constantly improve the growth,logging residue must be kept in the field otherwise N、 P、 K and Ca will be respectively lost 4%、13%、31% and 5% five years later,the pattern of site quality can be influenced.Breaking soil must be minimised for site preparation,deep tillage method was used in flat areas but mechanic minitype tools were used in hilly areas.Mechanization or minitype mechanization are the only route which eucalypt management must be passed.Odontotermes formosanus and weeds are harmful to eucalypt growth,and must be under control.Coppice is one of the main methods for eucalypt regrowth,less operations and costs,decreasing growth 16% but increasing profit 21% while harvesting at age of 7 years comparing with restablishment.It is typical silvicultural pattern of mosaic structure of eucalypt mixing with secondary forest in Brazil,especially around river,roads,the border of block and forest roads to protect the environment,isolate plant diseases and insect pests,beautify zoology and fire prevention.To complete all the works of planting,application of fertilizer and harvesting with high-quality it is the basic warranty to safeguard,respect and increase the terms of employment for labor forces.
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