二类调查区划固定小班的浅探

所谓固定小班就是二类调查小班（经理小班）现地定界，即图上小班线现地伐开、挂号、立标。 实行固定小班是二、三类调查结合的途径之一，利于生产，利于经营管理。天保工程及分类经营的现地定界给小班固定化提供了方便条件。 区划固定小班应在天保工程及分类经营划分的小区基础上区划小班。也就是以小区为单元，在小区内划小班。商品林根据小班划分条件区划小班；生态公益林可适当放宽，如果地类、优势树种（组）、起源、龄组、郁闭度级、林冠下造林等条件一致（其它条件无差别或差别不大，可不考虑）的情况下，可划一个小班，面积可放宽到…     

AUTOCAD图到ARCGIS9.3的导入与匹配

AUTOCAD制图精准灵活,但无绘制对象的数据库;而且AUTOCAD图不能透明染色。而ARCGIS9.3制图恰兼而有之。林业制图用ARCGIS9.3已成为一个必然趋势。而且在制图方面,已有大量的制成的CAD图资源,顺利实现AUTOCAD图到ARCGIS9.3的导入与匹配,能极大提高设计能力和效率。实现AUTOCAD图到ARCGIS9.3的导入与匹配,关键有三个技术,一是AUTOCAD图到ARCGIS9.3的有效导入;二是导入的AUTOOCAD图转换成ARCGIS9.3的Shapefile类型;三是将换成ARCGIS9.3的SHAPE类型图文件,按空间属性进行空间矢量配准。     

GIS技术在林业规划制图中的应用

GIS技术在各行各业中为人们的规划,决策和管理提供着便利和优越性,本文作者以林业规划制图为例介绍ARCMAP在林业规划制图中的应用,旨在改变传统的林业制图方式和方法,提高工作效率,提高数据的科学性和有效性。     

基于ArcGIS Engine的林业小班自动编号工具的设计与实现

传统的林业小班编号主观性强,存在费时、费力、效率低等特点。运用Arc GIS Engine在ArcGIS软件中增加林业小班自动编号工具,达到不论如何调整小班,都能准确、快速地给小班编号的目的,实现了小班编号的自动化。文中阐述了其设计思路,实现过程及部分代码,并给出了应用案例。     

林班小班的科学命名

随着森林经营水平的不断提高 ,计算机在林业资源管理中的广泛运用 ,林班、小班号的科学命名 ,就显得日益迫切和重要。1　现行的林班、小班号的命名方法及依据林班、小班是在林区区划时 ,在林场的范围内 ,为了便于生产、经营管理及资源统计计算 ,根据森林的经营水平、森林的林学特征及调查因子区划出的不同林分地段。现行林班小班的“命名”既林班号小班号是依据区划时林班及林班内小班的个数 ,按其排序的序数命名的。如某一林场按经营水平和林分结构可区划 2 0 0个林班 ,则从界内的方位起 ,按大小顺序分别用1、2、3…… 2 0 0排序并按序号命…     

Photoshop软件在林业制图及面积求算中的应用

将Photoshop软件应用于林业制图及面积求算工作.论述了地形图、卫星影像图的处理,图框制作,小班转绘,小班图、工程措施布置图制作等的方法、步骤;对运用Photoshop进行小班面积求算的原理和方法进行了阐述.     

浅谈平面坐标转换

随着GPS在林业事业中的作用日益重要,文章对GPS的组成、定位原理进行了简要的说明,同时结合实例对于利用AUTOCAD软件进行坐标系统转换及同一坐标系统下的换带计算进行了初步的研究。在已知两个坐标系下的两个以上的已知点的情况下,利用AUTOCAD软件进行坐标转换是切实可行的。     

森林资源二类调查中小班区划方法研究

通过对森林资源二类调查中小班区划方法进行改进得到连续小班区划方法 ,试验证明这种方法可以节省大量野外调查时间 ,大幅度提高小班界线区划的准确性 ,使小班界线相对稳定 ,调查成果可提供落实到山头地块的森林资源现状和动态变化数据及图面材料     

数量化模型Ⅰ小班蓄积调查法

<正> 小班蓄积调查指的是二类小班蓄积量的调查。《森林资源调查主要技术规定》要求按小班提供蓄积量,同时用抽样方法控制调查总体的蓄积量精度。但对远期开发的林区和经营强度较低的林区,可按小班进行分类,按林班或运材系统、大队或公社为总体提供资源数字。蓄积量调查的精度只落实到总体,而不要求落实到小班。二类小班调查的方法,三十年来,由目测、实测及标准地推测等方法,发展到目前广泛应用的总体抽样控制精度的小班调查法。从1976年起就想利用数量化方法进行二类小班蓄积量调查,但试验的结果,小班蓄积预     

黄泥河森林小班主导因子的聚类分析及经营措施

为了准确、及时地判定小班生长过程,本研究将聚类分析引入到小班生长主导因子研究中。以黄泥河林业局森林小班为例,以森林资源二类调查小班数据为基础,选取经营类型、立地类型一致的优势树种(组)——人工落叶松,通过反复试验,选用坡度(级)、龄级、郁闭度、每公顷株数、材积因子(HD2)5种森林小班主导因子进行聚类分析,将2 521个小班成功分为5类,并针对每一类森林小班及整体黄泥河林业局地区森林提出了相应的营林措施。     

Browsing Damage on Pine (Pinus sylvestris and P. contorta) by a migrating moose (Alces alces) Population in Winter: Relation to Habitat Composition and Road Barriers

In Scandinavia, moose (Alces alces L.) sometimes cause severe browsing damage to economically-important pine. Moose-vehicle accidents have spurred construction of fences along roads, and these may interfere with moose migration between summer and winter ranges, or the road alone may be a barrier. If this happens and moose build up along roads, landowners may suffer economically. Therefore, this study investigated whether roads, fences or other factors influence the use of young pine stands by moose. Eighty stands along roads in northern Sweden were evaluated in which individually-browsed branches were counted on 9972 pines. Moose browsing was not significantly related to birch (Betula pendula Roth, B. pubescens Ehrh.) density, nor did it differ between pines (Pinus contorta Douglas or P. sylvestris L.). However, increased pine density, site productivity and proximity to a highway were associated with increased browsing. Further large-scale studies are needed to understand moose habitat selection and the effects of roads.     

Effects of Root Freezing on the Physiology and Growth of Picea glauca,Picea mariana and Pinus banksiana Seedlings Under Different Soil Moisture Regimes

The root systems of 2-yr-old Picea glauca, Picea mariana and Pinus banksiana seedlings were submitted to various frost temperatures during an artificial frost to induce different levels of root damage. Frost-damaged and control seedlings were placed in a greenhouse under high and low soil moisture regimes. Seedling growth and physiology were evaluated periodically. Seedling survival was reduced when root damage reached levels of 60-80%. Root systems of all three species showed partial to total recovery by the end of the experiment. In general, root freezing damage caused reductions in seedling growth, with these reductions becoming less significant over time. Root damage had little to no effect on black spruce and jack pine seedling physiology, while white spruce CO 2 uptake decreased with increasing root damage. Shoot nitrogen content of all three species decreased slightly with increasing root damage.     

Stand Structure in Pine,Spruce and Deciduous Forests: A Comparison Between Finnish and Russian Karelia

This study investigated the stand structure in pine, spruce and deciduous forests in the border district of Finland and Russia. A total of 46 mature forest stands was selected as pairs, the members of each pair being as similar as possible with respect to their forest site type, age, moisture and topography. The stands were then compared between the two countries by means of basal areas and number of stems. The proportions of dominating tree species were 2-12% lower, and correspondingly the proportions of secondary tree species higher, in Russian forests. The density of the forest stock was also higher in each forest type in Russia. The forests in the two countries differed most radically in terms of the abundance of dead trees. The amount was two to four times higher in Russian deciduous and spruce forests, and in pine forests the difference was 10-fold. The stand structures indicated that Russian coniferous stands, in particular, were more heterogeneous than intensively managed pine and spruce stands in Finland.     

Growth and Terminal Bud Formation in Picea abies Seedlings Grown with Alternating Diurnal Temperature and Different Light Qualities

The root collar diameter and the height:diameter ratio are of particular importance in container-grown seedlings where a high density in the containers may produce spindly seedlings. Temperature regimes and light quality are known to affect plant growth. The aim of this study was to identify responses in Picea abies (L.) Karst. seedlings grown with light providing different red:far-red ratios and under temperature regimes with alternating day (DT) and night temperature (NT) from negative (DT < NT) to positive (DT > NT) difference (DIF) between DT and NT. Experiments were conducted in controlled environment chambers and in a daylight phytotron. Only limited thermoperiodic responses appeared in P . abies seedlings with respect to seedling height and dry weight accumulation. The formation of terminal buds, however, was clearly delayed in seedlings grown at negative DIF. The results indicate a requirement for day extension light that is high in far-red, to prevent terminal bud formation under natural short-day conditions. An extended study should be conducted to clarify the minimum level of light intensity and the optimal light quality needed to prevent terminal bud formation under natural short-day conditions.     

CAD与建筑设计的关系

本文分析了CAD在设计中引起的正面和负面影响,并进行了系统的阐述,从而使设计者在应用中能够保持客观的态度。     

Natural Regeneration in Clear-cuts: Effects of Scarification,Slash Removal and Clear-cut Age

The effects of soil scarification (mounding), slash removal and clear-cut age on the natural regeneration in clear-cuts was evaluated using data from four sites in southern Sweden. The treatments were carried out during a good seed and establishment year for birch ( Betula pubescens Ehrh. and B. pendula Roth). Scarification had the strongest positive effect on the density of naturally regenerated seedlings, especially in birch, but also in pine ( Pinus sylvestris L.) and spruce [ Picea abies (L.) Karst]. Slash removal had a positive effect on birch density. No statistically significant effect of clear-cut age was found. In addition, no statistically significant interactions between clear-cut age and scarification or slash removal were found. The ingrowth of field vegetation was the fastest in areas that were not scarified, less rapid in areas scarified on old clear-cuts, and the slowest after scarification in fresh clear-cuts. In conclusion, it may be possible to control the density of birch during a good establishment year for birch. If birch is desired, the best combination of treatments is to remove the slash and scarify; otherwise, these treatments should be avoided.     

Risk Perception Among Non-industrial Private Forest Owners

Based on an enquiry, risk perception among non-industrial private forest owners is described in relation to climate change and forestry hazards. Of the respondents, 11% took action to remedy the effects of climate change. Out of a given set, hazards were ranked according to each respondent's experience of recent substantial financial loss to the estate and in relation to his or her willingness to make investments aimed at risk reduction. For each hazard, the respondent assessed the risk in four classes ranging from very high to negligible risk. Six hazards were considered most problematic in all three aspects: browsing damage, falling timber prices, damage by wind, spruce bark beetle, root rot and pine weevil. A majority of the respondents claimed to take action to reduce the risk associated with at least one hazard, while 35% did not know whether they did. Excluding climate change, the need for decision support was the largest in relation to damage by wind owing to a combination of perceived high risk and a high level of ignorance in relation to whether risk-reducing measures were taken.     

Interactions in decomposition and N mineralization between tropical legume residue components

In situ produced plant residues contain a mixture of different plant components of varying quality. To assess synergistic or antagonistic interactions occurring during the decomposition and mineralization of such mixtures, individual plant parts (stems, leaves, leaf litter and roots) or the mixture of stems, leaves and leaf litter of the agroforestry species pigeonpea (Cajanus cajan) or of crop residues of peanut (Arachis hypogaea) or of the weed hairy indigo (Indigofera hirsuta) were incubated in pots for 19 weeks. Periodically, remaining plant residues were sieved out (>2 mm), weighed and N content as well as soil mineral N determined. Above- and below-ground residues of peanut decomposed fastest and showed the largest N release in agreement with their high N concentration and low-acid detergent fibre (ADF) : N ratio. Hairy indigo was hypothesized to be of lower quality than pigeonpea because of its high-polyphenol content. However, it decomposed faster than pigeonpea, largely because of the higher N and lower lignin concentration of its components. Ranking of individual plant components for N mineralization resulted in the following pattern, leaves > leaf litter > roots > stems. In mixtures of the different plant components a similar species order in decomposition was obtained, e.g. peanut > hairy indigo > pigeonpea. The amount of N released from the mixture was dominated by stem material that comprised 46–61% of the mixture. The interactions in mixtures were relatively small for peanut (generally high-quality components) as well as for pigeonpea (low proportion of high-quality components, i.e. N rich leaf material). However, a positive interaction occurred during later stages of N mineralization in the mixture of hairy indigo as it had a significant proportion of N rich components and absence of highly reactive polyphenols. Thus, for plants with low to intermediate chemical quality attributes, manipulating plant composition (e.g. by varying harvest age, affecting stem and leaf proportions) will be important to obtain significant interactions during decomposition when its components are mixed.     

Pasture production and tree growth in a young pine plantation fertilized with inorganic fertilizers and milk sewage in northwestern Spain

The use of organic waste materials such as milk sewage as an organic fertilizer could have the dual advantages of organic-waste disposal and reduced dependence on inorganic fertilizers. The effects of fertilization with (1) conventional mineral fertilization, (2) milk sewage sludge at 40 kg N ha⁻¹ target rate and (3) no fertilization on pasture production and tree growth were examined in an experiment consisting of two pasture mixtures under a one-year-old Pinus radiata plantation with a density of 2500 trees ha⁻¹. The two pasture mixtures were: (1) Dactylis glomerata L. var. saborto (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹); (2) Lolium perenne L. var. Tove (25 kg ha⁻¹) + Trifolium repens L. group Ladino (4 kg ha⁻¹) + Trifolium pratense L. var. Marino (1 kg ha⁻¹). The experiment began in the spring of 1995 using a randomized block design with three replicates in Castro Riberas de Lea (Lugo, Galicia, north-western Spain). Plot size was 12 × 8 m², with a 1 m buffer strip between plots. Two-year data showed that fertilization with either material had a positive effect on pasture production, with no significant difference between the two fertilization treatments. Tree growth in the milk sewage sludge plot was significantly higher than in the control plots. Inorganic fertilization increased pasture production, but affected tree growth negatively. The results show that milk sewage sludge could be used as a fertilizer in silvo-pastoral systems. This revised version was published online in June 2006 with corrections to the Cover Date.