百花山森林资源环境价值评估分析

百花山森林资源年产出价值为19 697.29万元,其中活立木价值年增长价值为3 080.65万元,占年总产出价值的15.64%,而间接使用价值,即生态价值为14 951.04万元,占年总产出的75.90%。说明百花山森林具有极高的生态效益价值,保存森林的价值,决不仅仅是木材价值的保护,更重要的应该是森林的生态效益的价值以及非消费性价值的保护。只有在生态价值不受损害的条件下,利用其他价值才是最合理的。     

Determination of Mean Tree Height of Forest Stands by Digital Photogrammetry

The mean tree height of 73 forest stands in a 1000 ha forest area was determined from canopy heights generated by automatic image matching using a digital photogrammetric workstation and digitized panchromatic aerial photographs with a scale of 1:15 000. First, the mean height of each stand was computed as the arithmetic mean of the quantile corresponding to the 75th percentile of the distribution of the canopy heights from the image matching within square grid cells with cell sizes of 236-400 m². The mean heights from the image matching underestimated the true heights by 5.42 m. Secondly, field-measured mean tree heights of 165 georeferenced sample plots distributed systematically throughout the 1000 ha forest area were regressed against the mean heights derived from the image matching. The regression equations were used to predict the mean heights of the 73 stands. In very young forest stands, the predicted mean heights overestimated the true heights by 0.4 m and the precision was 0.9-1.0 m. In young and mature stands, the average difference between predicted height and ground-truth ranged between -1.6 and 0.5 m, and the precision ranged from 1.1 to 2.1 m.     

Basic handling characteristics of wood fuels: Angle of repose,friction against surfaces and tendency to bridge for different assortments

Basic handling characteristics were measured for sawdust, fuel pellets, fuel chips, hog fuel and chunkwood. The aim was to find relations between the basic handling characteristics and easily measurable fuel properties to facilitate the design of feeding systems in heating plants. The angle of repose was 25–55° and increased with the increasing ratio of particle length to thickness and with the increasing content of hooked or long particles. The angle of static friction, 10–40°, was affected more by the kind of surface than the fuel and followed the ascending order: coated plywood, urethane rubber, particle board, stainless steel, concrete and rubber belt conveyor. The tendency to bridge varied considerably and increased with greater content of hooked or long particles, a deeper fuel bed depth over the opening and a higher moisture content. The results indicate that more attention should be paid to the particle shape.     

Fungicidal Control of Lophodermium seditiosum on Pinus sylvestris Seedlings in Swedish Forest Nurseries

During the 1990s, there were serious outbreaks of the pathogen Lophodermium seditiosum on pine seedlings in Swedish forest nurseries, even though the seedlings had been treated with the fungicide propiconazole. The present experiment was carried out to evaluate two other fungicides, fluazinam and azoxystrobin, as possible alternatives to propiconazole. In the tests, which were all carried out in the same forest nursery, seedlings were treated with either propiconazole, fluazinam or azoxystrobin, and the proportion of needles with ascocarps of L. seditiosum and the number of ascocarps per needle were recorded over the following 2 yrs. Seedlings treated with azoxystrobin already appeared healthier than control seedlings in September of the first year, and by November all azoxystrobin-treated seedlings had fewer ascocarps per needle compared with control seedlings. In autumn of the second year, there were no ascocarps on seedlings treated with fluazinam or azoxystrobin, whereas seedlings treated with propiconazole had similar numbers of ascocarps to non-treated control seedlings.     

西宁林业有害生物防治的专业化和社会化

近年来,西宁市将推进林业有害生物专业化、社会化防治作为全市森防工作的发展方向,进行了一些积极探索并取得了成效。本文对西宁市林业有害生物专业化社会化防治发展取得的成绩和存在的问题进行了分析,并提出了发展建议。     

Wood Production Potentials of Fenno-Scandinavian Forests Under Nature-Orientated Management

In Finland, Norway and Sweden forest management is presently changing towards a more nature-orientated management. In this study the European Forest Information SCENario (EFISCEN) model was applied to determine how this change might affect the potential for wood production in the three countries. Three different management regimes, traditional, traditional with nature conservation (''conservation''), and longer rotations with nature conservation (''conservation +''), were combined with two alternative felling levels. The results show that conserving 6.1-8.8% of the older forests in the southern regions had no limiting effects on production levels, as foreseen by the European Timber Trend Studies V by the UN-ECE for Finland and Sweden. Under the conservation + scenario, maximum sustainable felling levels decreased to 84, 79 and 72% of the present levels in Finland, Norway and Sweden, respectively. Increasing the rotation length put more pressure on the older age classes and thus did not increase the average age of the forest. If the consumption of wood increases as quickly as indicated by other studies, it will be hard to fulfil that demand and at the same time conserve considerable areas of forest in the southern regions of the countries.     

内蒙古自治区森林资源状况

文章以内蒙古第六次森林资源连续清查结果为依据,概述了内蒙古自治区森林资源及其生态状况,并针对存在主要问题提出森林资源保护与发展建议。     

高职院校《森林环境》课程教学改革的探索与实践

根据林业技术专业需要,以培养学生的综合素质和专业实践技能为主线,从教学内容、教学方法与手段、实践教学和考核方法等方面进行了改革探索与实践,取得了较好的效果。     

两种林龄中山杉(Taxodium hybrid 'Zhongshanshan')林地土壤质量评价

以江苏省靖江市牧城公园和东湖公园两种种植年限分别为5 a和9 a的中山杉(Taxodium hybrid'Zhongshanshan')人工林土壤和无林地为研究对象,对0~15 cm、15~30 cm和30~45 cm深度土层土壤理化性质、养分含量和微生物生物量进行了分析。典型相关分析表明,土壤微生物生物量的变化是一个复杂的过程,是土壤各因子共同作用的结果,3种土壤U、V值均表现出层次性,随着土壤深度的增加逐渐降低;不同取样点相同深度土层U、V值为9 a林5 a林对照;单相关分析表明,土壤微生物生物量与速效磷、速效钾、有机质和全氮呈极显著正相关(P0.01),因此土壤微生物可以作为评价中山杉人工林在促进林地土壤质量改善过程中的重要生物指标;主成分分析表明,综合得分最高的9 a林为2.993,其次是5 a林为0.748,作为对照的无林地则为-3.742,说明9 a林地土壤质量最高。可见,中山杉对林下土壤质量有显著提高作用。     

Fuel consumption as indicator of the economics in mechanization

After a brief discussion of production functions as models for input/output relations in forest work operations, studies of the cost of machine use are reviewed. It is suggested that the fuel consumption of a forest machine can be used as a parameter for assessing the true, total cost of using a machine, exclusively the wage of the operator. Fuel then is not only an input but also represents all other cost items such as capital (depreciation, interest), repairs and maintenance. This has the advantage that all machines in a system can be aggregated and their costs assessed by an easily quantified parameter. Capital (in the form of machines) in production functions, through which the optimum mix of labour and machines for minimizing the cost per unit of production is determined, can be substituted by fuel. It is also suggested that fuel consumption can be used in management as an aggregate indicator in planning, control, remuneration of work and forecasting.