飞机外挂物挂装设备综述

根据飞机外挂物挂装方式的不同,说明了飞机外挂物挂装设备分类;介绍了不同挂装设备的结构特点和通用挂装车的功能：阐述了飞机外挂物挂装设备国内外现状。     

解放CA3165K2E型汽车在运材中的应用

将解放CA3165K2E型长头柴油自卸汽车底盘用于林业运材汽车底盘，对其车架、板簧和后桥等总成采用的金属材料和制造工艺进行了分析，并对一年的生产运输成本进行统计，结果表明，解放CA3165K2E型汽车技术先进、质量可靠、坚固耐用，性价比高、经济性好，能够给林业木材运输企业带来良好的经济效益。     

不同线路方案运材车速度及耗油量的比较

林道工程师早就知道如何估算运材道路的建筑费用,但在道路建成之前,却无法很好地预估道路建成之后的车辆运营费。本文阐述了如何在线路方案比较中,考虑运营费的两个主要部份——运行时间及燃油消耗。文中数据是作者在留学新西兰期间的实测数据,但所阐述的基本方法则是任何国家都可采用的。     

Invasion of Non-Commercial Tree Species After Selection Logging in a Bolivian Tropical Forest

Abstract

Single-tree selection logging will likely result in a 4.3% loss in the relative abundance and a 4.1% loss in basal area of trees of commercial species in one cutting cycle due to their removal by harvesting combined with their potential recolonization of only 31% of logging gaps in a Bolivian tropical dry forest. Densities of the most valuable species, Amburana cearensis and Cedrela fissilis, were particularly reduced by logging. To sustain the current harvesting rate, uses need to be developed for more non-commercial species and/or silvicul-tural treatments employed that increase regeneration of commercial species and remove non-commercial species using timber stand improvement techniques.     

中芬采运技术比较与经济分析

本对中芬的木材生产工艺流程、经营方案，生产劳动组织以及不同采运方式做了技术和经济分析。     

Lichen species diversity and substrate amounts in young planted boreal forests: A comparison between slash and stumps of Picea abies

The increasing demand for biofuel may decrease the dead wood supply in managed forests, and hence the amount of substrate available for dead wood dependent species. Slash is already being harvested for biofuel purposes, and stumps are an even bigger potential source of wood fuel. Both substrates constitute a major component of dead wood in managed forests, but have been poorly studied in terms of lichen diversity. We compared lichen species diversity between the lateral surface of slash and the cut surface of stumps of Norway spruce in planted boreonemoral Swedish forests of four age classes; 4-5, 8-9, 12-13, and 16-18 years. We also estimated the amounts of the two substrates, and discriminated between slash with bark and decorticated slash. There were no differences in species number per surface area, but slash had more species when equal volumes were compared. We found compositional differences between slash and stumps throughout the decay process. The majority of species found on both substrates were more frequent on stumps, which also had a higher number of unique species and species in the literature indicated as nationally rare or uncommon. The volume per hectare of stumps was ten times greater than that of slash but conversely, the lateral surface area of slash was five times greater than the cut surface area of stumps. Few dead wood specialist lichen species were, however, strictly associated with slash, whereas stumps offer a more heterogeneous environment and may provide important habitats for rare lichens in the managed forest landscape.     

某电动载货车后桥的有限元分析

对某电动载货车后桥在垂直静载、紧急制动工况时的受力情况进行研究,利用有限元分析软件ANSYS Workbench对某电动载货车后桥的结构强度进行分析。并通过台架试验验证了该有限元分析方法的有效性。根据有限元分析结果和台架试验的试验结果,对某电动载货车后桥零部件中强度薄弱的板簧托架进行结构优化,以满足电动载货车后桥的强度设计要求。     

Mechanical cleaning and prescribed burning for recruiting commercial tree regeneration in a Bolivian dry forest

A critical component of sustainable forest management is the regeneration of commercially valuable tree species. Mechanical cleaning with machetes and chainsaws, prescribed burning, and a combination of both treatments were applied to recently-created logging gaps in a Bolivian dry forest to evaluate their impact on the natural regeneration of commercial tree species and on control of competing vegetation. The three treatments and an untreated control were applied to logging gaps during the dry season of 1998 and replicated ten times. Eight months following burning, the density of commercial tree regeneration in gaps did not differ statistically among treatments. Relative height growth of total commercial regeneration also did not differ among treatments, although it did vary by species. Reduction in competing vegetation following the application of site preparation treatments was significantly higher, but competing plant cover was beginning to converge among treatments after eight months. Despite better control of competing vegetation, early recruitment and growth responses to burning and cleaning of vegetation in logging gaps do not appear to justify application of these treatments in this forest, especially considering their high costs.     

如何充分有效地利用好现有的森林资源

本文结合带岭林业实验局的实际情况，讨论了实施天然林保护工程后，如何合理采伐森林，充分有效地利用好现有的森林资源。     

Timber tree regeneration along abandoned logging roads in a tropical Bolivian forest

Sustainable management of selectively logged tropical forests requires that felled trees are replaced through increased recruitment and growth. This study compares road track and roadside regeneration with regeneration in unlogged and selectively logged humid tropical forest in north-eastern Bolivia. Some species benefited from increased light intensities on abandoned logging roads. Others benefited from low densities of competing vegetation on roads with compacted soils. This was the case for the small-seeded species Ficus boliviana C.C. Berg and Terminalia oblonga (Ruiz & Pav.) Steud. Some species, e.g. Hura crepitans L., displayed patchy regeneration coinciding with the presence of adult trees. Our results suggest that current management practices could be improved by intensifying logging in some areas to improve regeneration of light demanding species. Sufficient seed input in logged areas should be ensured by interspersing large patches of unlogged forest with logged areas. This may also assist regeneration of species that perform poorly in disturbed areas.