森林采伐作业环境保护技术

森林采伐应注重经济效益与生态效益的有机结合已成为共识。本文对采伐作业引起林地土壤的干扰与压实、土壤养分变化、保留木的损伤以及采伐作业后溪流水质的变化、林木更新和生长的影响进行归纳和评述 ,介绍了可减少立地破坏的采伐作业技术和采集机械应用的新进展 ,指出我国开展森林采伐作业环境保护技术的研究对策     

贵州马尾松人工建筑材林合理采伐年龄研究

依据所建马尾松人工林生长收获模型系统，分析了不同立地指数（１４￣２０）的生产力，确定了各指数级适宜培养目标。根据培养目标，立地和栽培措施的不同，设计多咱建筑材培育类型，并分别求出了不同培育类型的数量、工艺、经济成熟龄，以此为基础确定了各指数级合理采伐年龄，使采伐年龄较目前正在执行的采伐和年龄（３１￣４０ａ）缩短４￣１２ａ，内部收益率提高３￣９个百分点。研究了立地、培育目标、经营状况（初植密度，间伐     

不同立地类型杉木人工林伐根材积表的编制

在武冈林场应用数量化逐步回归方法建立地位指数模型,编制数量化地位指数表,并用聚类方法划分立地类型。同时建立了不同立地类型杉木伐根与胸径、树高的关系模型,依此确定被伐木的材积,对于测定滥伐后的林木材积和检查、评估采伐量具有指导作用。     

国营林场抚育间伐伐区工艺设计诸问题研探

本文对抚育间伐伐区工艺设计中的采伐类型、伐区等级、间伐强度、作业定额、设计表的研究提出探讨意见。     

森林采伐作业中防止水土流失的几个问题

森林工业对环境影响最大,破坏最快是在采伐的时候。森林采伐严重而迅速地破坏森林的生态系。由于采伐时的不注意,使林地毁坏,肥力减退,水道堵塞。对林业工作者来说,主要的是采伐对水土保持的影响问题。作业计划务须考虑涨水、水土流失以及必然出现的沉积的后果。采伐方式应根据森林植被的状态、土壤类型、地形和气候条件来确定。一般说来,采伐后迹地上的水流量会立即增加。林地破坏越大,沼泽化越严重,     

南方集体林区完善林木采伐设计问题的探讨

分析了各采伐类型、采伐方式的林木采伐设计必须提交的实质性内容，并以浙江省缙云县各采伐类型、采伐方式林木采伐作业设计为例，提出了应当规范和完善的内容，旨在提高林木采伐设计水平，并对林木采伐设计的两个问题进行探讨。     

同龄林经营决策模型的应用

文章以间伐作业的同龄林为例 ,建立了各立地质量条件下的收获调整模型。运用动态规划理论分别讨论了林分总收获量最大、材积产量最大及经济效益最大时林分采伐进程的安排     

坤都经济林场文冠果全周期小班作业法探讨

文章以内蒙古阿鲁科尔沁旗坤都经济林场文冠果经营为研究对象,采用综合分析法对林分立地类型与等级、林分平均年龄及胸径树高等自然环境条件和林分概况进行全面分析,对文冠果经营活动所涉及的造林、抚育、修复、采伐、更新等环节的一系列经营技术措施,进行基于适用对象、目标林相和具体经营措施的设计,提出了文冠果森林经营全周期小班作业法。     

雅鲁藏布江中游巨柏种群立地分类研究

基于微立地对雅鲁藏布江中游朗县巨柏种群立地类型进行划分,为探索微环境对巨柏生长的影响,以雅鲁藏布江中游朗县巨柏种群为研究对象,采用定性的经验总结和定量的数学分析相结合的方法,并参考中国森林立地分类、西藏地貌、西藏自然地理及各立地因子进行主成分分析后划分立地类型,共划分出5个立地类型组:岩石裸露地立地类型组、山麓坡地立地类型组、阶地立地类型组、河滩地(河漫滩)立地类型组和水线岸边立地类型组,以及15个立地类型。将雅鲁藏布江中游朗县巨柏种群立地类型与中国森林立地分类相结合,得到了朗县巨柏种群立地类型,可为进一步探索立地类型对巨柏生长的影响以及对西藏河谷地带立地类型划分的方法提供参考。     

仙游县森林资源现状分析与发展途径探索

在叙述仙游县森林资源6个特点以及对林地立地、林种结构、树种结构、龄组结构、林分生长类型、森林资源消长进行分析的基础上,提出加强林政管理,严格控制采伐;注重集约经营,扩大森林资源;调整林种结构,发挥森林多种效益;加速基地建设,培育后续资源等发展森林资源的途径。     

Improved harvesting systems for wet sites

Environmentally acceptable and economical forest operations are needed for sustainable management of forest resources. Improved methods for harvesting and transporting timber are especially needed for wet sites. As the demand for hardwood lumber continues to increase, improved and alternative methods are needed to ensure acceptance of timber harvesting for the wet site conditions that are typical of bottomland hardwoods. Some alternative technological developments include grapple saw feller-bunchers, wide tires, larger forwarders, clambunk skidders, two-stage hauling, mats, cable systems, helicopters and towed vehicles and air-cushioned vehicles. These developments have the potential to improve the performance of the harvesting system and to reduce the negative effects of conventional operations on conventional sites and on difficult sites such as wet areas. Although many of these new alternatives are now operational, others are just concepts or evolving prototypes. More research is still needed to optimize these alternative technologies and to reduce costs associated with their implementation.     

森林采运系统动力学模型研究

为了分析森林采运系统的效率和成本,本文选择系统中关键的采—集过程,利用系统动力学的方法建立模型,进行计算机仿真模拟。结果显示,以特定时间范围内完成一定工作量为前提,系统运行的效率和成本与初始设备的投入量关系不大,与设备条件、外部条件、林木条件等关系很大。但初始采造设备的投入量会影响集材设备的运行效率和成本。在实际生产中,首先应根据林木条件和外部条件选择合适的设备,这样才能使得运行效率最高而成本最低;其次在设备的安排上,应充分保障采造设备,但也不应使其生产力与集材设备的生产力相差过大,否则会造成后期集材设备需求激增等问题。     

基于联合仿真的林业采育作业模拟系统研究

为解决大型林业装备操作训练复杂的问题,优化驾驶与作业,提高森林资源利用率,本文提出基于分布式系统,对采育作业环境进行视景模拟的虚拟现实作业操作模拟器。系统利用虚拟现实软件Unity3D系统,能够模拟车辆行驶与工作的动力学模型,实时运动仿真包括底盘系统与地面的交互作用,机械臂作业运动以及伐木头作业操作运动,使操作人员能够更快地适应熟悉驾驶和采育作业,减少安全隐患和装备损耗,提高装备作业安全性及效率。     

Threshold effects of variable retention harvesting on understory plant communities in the boreal mixedwood forest

We studied the effects of six levels of dispersed green-tree retention (GTR) harvesting (clearcut (0%), 10%, 20%, 50%, and 75%, and unharvested reference (100%)) on understory plant communities in the 8th growing season post-harvest in the mixedwood boreal forest in northwestern Alberta. For the partial harvest treatments (10%, 20%, 50%, 75%) sample plots were located in the partially harvested (retention) strips as well as in the intervening machine corridors used by the harvesting equipment. The understory plant community was significantly influenced by the gradient of retention level. The cover of understory vegetation, especially graminoids, increased with increasing harvesting intensity for the retention strips and overall considering both plots types. Species richness was unaffected by retention level but did decrease as tree density increased. Lower levels of retention lead to increased abundance of early successional, shade-intolerant species. The results suggest a threshold in understory response to GTR harvesting between the 10% and 20% retention treatments. In terms of understory cover and composition, machine corridors within partially harvested forests resembled clearcuts. The results suggest that retaining more than 10% during GTR harvesting could have significant benefits in terms of maintaining understory plant communities more similar to unharvested reference forest.     

Effects of forest residue harvesting on short-term changes in soil solution chemistry

Short-term (three to four years) effects of forest harvesting on soil solution chemistry were investigated at two Norway spruce sites in southern Norway, differing in precipitation amount and topography. Experimental plots were either harvested conventionally (stem-only harvesting, SOH) or whole trees, including crowns, twigs and branches were removed (whole-tree harvesting, WTH), leaving residue piles on the ground for some months before removal. The WTH treatment had two sub-treatments: WTH-pile where there had been piles and WTH-removal, from where residues had been removed to make piles. Increased soil solution concentrations of NO₃–N, total N, Ca, Mg and K at 30?cm depth, shown by peaks in concentrations in the years after harvesting, were found at the drier, less steep site in eastern Norway after SOH and WTH-pile, but less so after WTH-removal. At the wetter, steeper site in western Norway, peaks were often observed also at WTH-removal plots, which might reflect within-site differences in water pathways due largely to site topography.     

采种技术及其微型动力采摘设备的研究

从我国山地林区采种特点出发,针对采种作业中存在的技术难题,首次提出了能适应多树种的林木种子高效采摘技术新方案,并完成了其微型动力采摘设备的研究。     

林木种子采收技术与装备研究进展

种子采收环节是林业生产循环中的重要组成部分,林木种子采收技术及装备的发展水平直接影响到林业的可持续发展。文中主要介绍我国林业、林木种子繁育基地的现状与发展前景,采种技术的类型以及国内外相关采种装备的研究进展和应用,分析山地、林地复杂环境对大型机械设备作业的影响和其必须具备的性能特点。     

Harvesting and extraction impacts on Eucalyptus grandis × E. urophylla coppicing potential and rotation-end volume in Zululand,South Africa

From the early 2000s there has been a general shift in South Africa in harvesting and extraction systems from the use of semi- to fully-mechanised systems. Any increase in mechanisation, as is occurring in Zululand, will need to take into consideration damage to stumps and the subsequent ability to regenerate by coppice. In 2002, four types of harvesting and extraction systems, arranged in a randomised complete block design, were used to clearfell a stand of E. grandis × E. urophylla. A motor-manual harvesting system was used to carry out the manual harvesting system (Man). The fully mechanised system (Mech) consisted of a single-grip harvesting head used with a tracked excavator to carry out all felling and processing operations. Two additional systems (Man_Mech_3W and Man_Mech_Flexi) had increased levels of mechanisation over that of the Man treatment. Both these harvesting systems made use of a Bell debarker, with loading carried out by a Bell three-wheeled loader in the Man_Mech_3W, and by a Flexiloader in the Man_Mech_Flexi treatments. Data collected from these four treatments were used to determine the effects of mechanised harvesting systems on type and severity of stump damage, coppicing potential and coppice growth over the rotation. Irrespective of harvesting system, more damage occurred to the top than bottom half of the stump, with a significant decrease in coppice regrowth with increasing stump damage. Most damage and least coppice regrowth occurred in the extraction rows where the damage recorded could be attributed to vehicle movement, tear-outs and/or log stripping. There was no significant difference between the harvesting systems in terms of stump mortality, final stem stocking and rotation-end volume. Thus, individual components within each harvesting system can have a larger impact than the overall harvesting system used. Future research should focus on these components, and where associated damage occurs for a specific component, this should be lessened through management intervention, training or technological improvements.     

马来西亚森林采伐管理制度研究

林业在马来西亚一直占据相当重要的位置。文中从法律基础、管理体系、轮伐期的确定、森林经营方案制度、采伐审批许可、采伐管理、木材运输以及奖惩措施等方面对马来西亚的森林采伐管理制度进行了全面分析, 并提出加强我国森林采伐管理的建设性意见。