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我国主要立地火炬松纸浆材,建筑材林合理轮伐期的研究 总被引:2,自引:0,他引:2
本研究根据多目标决策层次分析的原理,确定经济成熟龄和工艺成熟龄对于纸浆材林主伐年龄和建筑材林主伐年龄的权重分别为:W1=(0.875,0.125)和W2=(0.500,0.500)。根据火炬松人工林生长、结构、经营模型和材种出材量模型,确定火炬松的经济成熟龄、工艺成熟龄,从而确定两材种的主伐年龄。根据主伐年龄+更新周期即为轮伐期,确定了火炬松南、中、北三带主要立地类型(14-20)、主要密度类型( 相似文献
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赵海林 《中南林业调查规划》1984,(1)
林分密度控制图是科学经营现有森林,合理利用土地资源的一种森林经营图。它可用于定量间伐、资源清查、生长予测、因地制宜确定更新树种、初始密度、培育年限和材种规格、按培育目标控制林分密度等,以达到森林的永续高产和多效益的经营目的。可见它是提高森林经营水平的重要工具,但编制密控图的模型和公 相似文献
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中幼龄林抚育在现代林业中的应用 总被引:3,自引:0,他引:3
抚育采伐或间伐是根据林分发育、自然稀疏规律及森林培育目标,适时伐除部分林木,调整树种组成和林分密度,改善环境条件,促进保留木生长的一种营林措施。抚育采伐是从幼林郁闭开始到成熟林采伐(主伐)前一个龄级的这一段时间内,在森林中对部分林木进行的采伐。 相似文献
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引言森林主伐龄是指同一森林经营类型的林分进行正常主伐的最低年龄。确定森林主伐龄的主要技术依据是森林成熟。工艺成熟是主导因素;数量成熟龄是确定主伐龄不可低越的下限;自然成熟龄是不可超越的上限。同时,兼顾防护成熟、经济成熟及更新成熟。 相似文献
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一、主伐方式 根据林分面积和分布特点,确定主伐林龄时必须达到以下三项指标。一是皆伐后保证生态环境不受破坏。二是确定的主伐林龄必须达到“数量成熟”或“工艺成熟”,按市场需要材种、规格达到最高值,具有最高的采伐价值。三是皆伐后必须保证人工更新效果,达到《森林经营技术规程》所要求的指标。 相似文献
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lntroductionChinesepine(Pinust8blaeformNisoneofthemostimportanttreespeciesforafforestationandwidelyspreadinTaihanglimestonemountains,ShanxiProvince.Ittakes85%ofthetotaIareaofpIantations.ChinespineplantationsplantedaremainIyforpurposeofsoiIandwaterconservationandtimber.TheinvestigationofChinesepinepIantationsmadelastdecadeshowedthat,accordingtotheirsitecondition,theexistingstandsdidnotmeettheappro-priatedensity.Standsstructureisuniform.Waterlossandsoilerosionareserious,andsoiffertilitygetd… 相似文献
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Exploring adaptation to climate change in the forests of central Nova Scotia, Canada 总被引:1,自引:0,他引:1
James W.N. Steenberg Peter N. Duinker Peter G. Bush 《Forest Ecology and Management》2011,262(12):2316-2327
The threat of climate change is now recognized as an imminent issue at the forefront of the forest sector. Incorporating adaptation to climate change into forest management will be vital in the continual and sustainable provision of forest ecosystem services. The objective of this study is to investigate climate change adaptation in forest management using the landscape disturbance model LANDIS-II. The study area was comprised of 14,000 ha of forested watersheds in central Nova Scotia, Canada, managed by Halifax Water, the municipal water utility. Simulated climate change adaptation was directed towards three components of timber harvesting: the canopy-opening size of harvests, the age of harvested trees within a stand, and the species composition of harvested trees within a stand. These three adaptation treatments were simulated singly and in combination with each other in the modeling experiment. The timber supply was found to benefit from climate change in the absence of any adaptation treatment, though there was a loss of target tree species and old growth forest. In the age treatment, all trees in a harvested stand at or below the age of sexual maturity were exempt from harvesting. This was done to promote more-rapid succession to climax forest communities typical of the study area. It was the most effective in maintaining the timber supply, but least effective in promoting resistance to climate change at the prescribed harvest intensity. In the composition treatment, individual tree species were selected for harvest based on their response to climate change in previous research and on management values at Halifax Water to progressively facilitate forest transition under the altered climate. This proved the most effective treatment for maximizing forest age and old-growth area and for promoting stands composed of climatically suited target species. The size treatment was aimed towards building stand complexity and resilience to climate change, and was the most influential treatment on the response of timber supply, forest age, and forest composition to timber harvest when it was combined with other treatments. The combination of all three adaptation treatments yielded an adequate representation of target species and old forest without overly diminishing the timber supply, and was therefore the most effective in minimizing the trade-offs between management values and objectives. These findings support a diverse and multi-faceted approach to climate change adaptation. 相似文献
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在四川本部高山冷杉林区,冷杉腐朽病的危害性在于降低了林分出材率,改变了林木材料结构。通过2849株冷杉伐倒木测定表明,冷杉林木发生腐朽后,林种结构有明显的变化,优良林种下降,加工材增加。在冷杉林木出材率方面,腐朽木较健康木下降8.4-28.8%(平均14.9)。冷杉林区冷杉林分出材率,与林分年龄的腐朽率,林分径级的腐朽率均呈极显著的负相关。回归方程分别如下:Y=81.46-0.21x1,Y=82. 相似文献
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基于2018—2020年浙江省龙泉市900宗活立木交易数据,采用半对数多元线性回归模型研究木材市场价格、单位面积蓄积、林分质量等因素对活立木交易价格的影响。结果表明,龙泉市活立木交易平均价格为3 976元/hm2,木材市场价格、单位面积蓄积、单位面积株数、平均胸径对活立木交易价格有显著的正向影响;流入方性质和流出方性质对活立木交易价格有显著影响,且影响存在差异性。提出规范木材市场交易,加强森林资源评估工作,提升交易的公平性,全面推进林权抵押贷款等建议。 相似文献