共查询到20条相似文献，搜索用时 140 毫秒
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通过对甘肃省三北防护林体系建设工程的林分退化现象进行分析研究，得出林分退化的主要原因包括生理过熟、立地条件不良、树种选择不当、人类干扰和有害生物影响五个方面，结合甘肃省的实际情况，就不同的退化原因提出了相应的修复措施，主要有重新造林、补植补造、抚育管护以及必要的病虫害防治等措施。 相似文献
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通过对沈阳市防护林的现状与结构分析,阐述了沈阳市防护林的退化原因、退化程度、龄组分布等特点,分析沈阳市防护林现存的问题,并提出对沈阳市退化防护林的修复措施和建议。 相似文献
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针对我国西部地区的荒漠及荒漠草原退化生态系统的特征及退化的原因分析,提出了恢复与重建的途径和方法．并提出了相应的技术措施。 相似文献
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本文调查了我国山核桃重点产区——安徽省宁国市山核桃林生态环境退化情况,分析了经营方式、化学投入品等导致山核桃林生态系统退化的原因,提出以自然修复为前提,加强营林措施、生草栽培、引种紫穗槐等人工促进生态修复技术措施。宁国市自2010年开始全面实施山核桃林生态修复与重建工程,全面禁用除草剂,已推广割灌机8000余台,推广频振式杀虫灯1550盏,生物措施修复的山核桃林达到0.5万hm2,有效遏制了山核桃生态系统退化的趋势。 相似文献
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辽宁三北防护林退化林分的现状、成因及修复措施 总被引：2，自引：0，他引：2
目前,森林退化是全世界都在面临的严峻问题,这个问题严重阻碍了21世纪的全球环境发展,因此需要我们对该问题进行关注,积极寻找其中的原因并给予解决。本文笔者将对我国辽宁三北防护林退化林分的现状进行简要的分析,并从中得出导致防护林发生退化的原因,并根据其原因提出相应的修复措施。 相似文献
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《中国林业科技(英文版)》2010,(2):24-31
In recent decades, there has seen a dramatic expansion of global planted forest area and their great impact on human life. It is reported in Forest Resource Assessment 2010 that the current area of global planted forests is about 264 million ha, representing only 7% of the total forest area but able to meet the two thirds of the global demand for logs. Planted forests can not only provide timber, fiber, fuel and non-wood forest products, but also contribute to carbon sequestration, restoration of degraded l... 相似文献
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全球人工林环境管理策略研究 总被引：1，自引：0，他引：1
全球人工林为木材生产和缓解贫困做出了重要贡献, 在减缓和适应气候变化中起到了非常重要的作用。文中在介绍全球人工林资源的基础上, 分析了人工林对生物多样性、水分循环、养分循环和碳循环的影响和相互作用机制, 提出了人工林环境管理策略, 即建立人工林多功能经营制度、通过森林认证助推人工林可持续经营、充分利用REDD+机制提高人工林固碳效应的政策推动策略, 加强生物多样性保护、降低人工林对水循环负面影响、提高人工林的养分循环、促进人工林生态系统碳循环的生态系统完整性策略, 以及保育高保护价值区域策略和鼓励利益相关者参与人工林规划与管理策略。 相似文献
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50年代在山西省北部地区为减小风沙危害，人们营造了大面积的小叶杨纯林，但随着时间推移，防护林功能逐年下降。为了提高林分稳定性，形成稳定的森林生态体系，营造了多树种混交林，并收集了樟子松、华北落叶松、侧柏、刺槐、旱柳、白榆、辽东烁、杏树、白桦、白蜡及山丁子等树种基因资源，为今后的深入研究打下了良好基础。 相似文献
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集约经营人工林的环境保护效应研究 总被引：1，自引：0，他引：1
为了揭示造林工程对环境产生的影响,特别是高标准造林和幼林经营活动对造林地水土流失的影响,在安徽省"世界银行贷款国家造林项目"和"世界银行森林资源发展和保护项目"新造林地有代表性地区设置水土流失定位观测点、建立径流小区,进行连续水土流失定位观测,并查阅与借鉴国内外有关经营人工林的资料,系统探索、分析了集约经营人工林在环境保护方面的效应. 相似文献
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Planted forests in many forms are parts of landscapes in many regions of the world. These forests contribute to the economic welfare and potential sustainability of human communities. They provide wood, forage, wildlife habitats, watershed protection, recreational settings, aesthetic vistas, and ecological conditions for many other forest values. Forests and other versions of tree plantations have been planted to replace harvested Douglas-fir forests in Oregon, to provide fuelwood and forage in Senegal, for pulpwood in Brazil, for lumber in New Zealand, for watershed protection in Nepal, and for aesthetic enhancement in Scotland and Denmark. As human pressures on native forests continue to increase -- for reasons ranging from fuelwood needs to desires to preserve old-growth ecosystems -- it is clear to many of us that planted forests, intensively and extensively managed, are essential to our present and future societies and cultures, whatever forms they take. 相似文献
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In the Central Hardwood Forest region of the United States, the variable and somewhat unpredictable establishment success of hardwood tree plantations has traditionally been attributed to competing vegetation and damage due to animal browse. We examined operational plantation establishment success (1–5 years following planting) as it relates to use of particular silvicultural practices. Silvicultural histories were obtained for 87 randomly selected plantations throughout Indiana and field data were collected from each to determine tree survival, tree vigor, and abundance of surrounding vegetation. Survival was highest at sites that were treated with herbicide prior to planting and that had been mechanically planted (as opposed to hand planted). The percentage of trees with evidence of dieback was highest on sites at which browse protection measures had been used, likely reflecting a combination of damage due to inherently high white-tailed deer (Odocoileus virginianus Zimmermann) populations at such sites and ineffectiveness of current browse protection measures. Sites planted by a professional forester and those with herbicide applied subsequent to planting had a higher percentage of trees deemed free-to-grow. Subsequent herbicide application did not reduce cover or height of competing vegetation; however, when used in conjunction with mechanical site preparation techniques, overall cover and height of herbaceous vegetation was reduced. 相似文献
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辽宁省章古台樟子松固沙林更新的研究 总被引：4，自引：1，他引：4
章古台樟子松固沙林 ,是建国初期在东北西部与内蒙古东部防护林工程建设中营造的试验示范林。樟子松固沙林发挥了显著的生态效应与经济效应 ,它改善了沙地土壤与小气候条件 ;樟子松林的生物产量比较高 ,为 2 .7～ 3.4t/ (hm2 ·a)。樟子松固沙林提早更新的原因 ,主要由于引种地区跨越的纬度大 ,土壤气候条件差异大 ,引起树木自身生育规律的变化 ,生育期提前且缩短。另外 ,由于营造单纯林 ,林分密度高 ,水分亏缺 ,以及感染枯梢病等 ,使生育期更加缩短 ,章古台樟子松更新的林龄为 4 0～ 4 5a。更新的目标是 ,营造结构合理且稳定性比较高的乔灌草型、利用与治理相结合的新模式林 相似文献