几种中长期化学采脂刺激剂的性状及其应用

介绍近年来在化学采脂方面推广应用的几种中长期采脂刺激剂增产灵-2号，9205低温采脂剂、松树增脂剂、松树增脂剂的性状及使用方法。     

油松松脂采脂技术简介

在油松松脂采割试验的基础上，总结出了采脂林分及采脂树个体选择、割面方向选择、采脂起始高度、刮面配置、采脂工艺、采脂间隔期、采脂期确定等技术要点，符合油松采脂林木特性，适宜油松采脂作业，技术可行。     

采脂结合施用松树增脂剂对湿地松中龄林生长的影响及效果分析

对湿地松中龄林进行采脂，研究采脂对其生长的负效益，并结合增脂剂的应用，测试其增产效果和对林木生长的促进程度，为湿地松中龄林大面积进行采脂开发和增脂剂的推广打下理论基础。     

河南省马尾松采脂量与树体因子关系的研究

通过设置１４块标准地进行采脂试验研究，结果表明，马尾松采脂量与采脂树木的胸径、树贞与树冠大小呈一元线性回归关系，其中采脂量与胸径相关关系极显著，在胸径为１６ｃｍ时，年采脂量为２．５６４ｋｇ；根据我省马尾松资源现状，、应贯彻以生产木材产品、生产松脂为副产品的经营原则；采脂树木胸径应不于１６ｃｍ，以下降式采脂方法为宜。     

湿地松采脂试验报告

本试验以大田县桃源林场13年生的湿地松为材料,对湿地松产脂量、最佳采脂间隔期的选择、采脂对湿地松生长量的影响进行试验研究,并采用方差分析等方法,对湿地松7种不同处理方法进行差异显著检验,确定合理的采脂间隔期。结果表明,胸径17cm的湿地松平均单刀产脂量为32g;采脂间隔期3—5天,不仅产脂量较大,而且对湿地松生长量影响小。     

松树钻孔法采脂技术研究

以我国最主要的采脂树种马尾松、湿地松进行钻孔法采脂试验,探索了不同钻孔工艺和受脂方法对产脂量的影响以及钻孔法采脂对松树生长的影响.试验结果表明,马尾松钻孔用溶脂剂处理对延长其流脂时间和提高产脂量无明显效果;湿地松采用钻孔法采脂,产脂量除受树径大小影响外,还与孔径大小、钻孔方法、受脂方法等钻孔工艺条件有关,其影响程度孔径大小＞钻孔方法＞受脂方法;就单株采脂树的年产脂量而言,湿地松钻孔法采脂比常法采脂低,但钻孔法采脂可间隔20～30 d钻一次孔,对提高采脂劳动生产率有一定作用;钻孔法采脂对松树生长的影响比常法采脂小得多,有利于松树在采脂期间的生长.     

红松采脂试验初报

通过对29～30年生红松采脂试验得出，单株采脂量与径级、季节相关紧密：与采脂负荷率关系不大，但与林分株密度相关显著，为人工红松采脂提供一定经验。     

马尾松小径材化学采脂效益分析

利用化学采脂方法，对马尾松小径材进行伐前采脂试验，结果表明，利用化学采脂能大大提高劳动生产效率，降低小径材伐前采脂成本。同时小径材的平均单株采脂量也得以提高，较大幅度地提高了马尾松小径材的利用价值和经济价值。     

湿地松采脂研究

通过对近几年来在湘潭、株洲、衡阳等地的调查研究，分析了湿地松的产脂状况和特点，总结出其产脂曲线、单刀产脂量和年产脂量等规律，肯定了湿地松采脂的显著经济效益和社会效益。     

松脂增脂剂研究进展

近年来,采脂劳动成本上涨,国内采脂工艺研究没有突破性进展,脂农采脂积极性不高,松脂产业发展缓慢.高效的增脂剂能提升松脂产量,提高采脂率,促进松脂产业健康发展.该文对化学增脂剂、生物增脂剂和复合增脂剂3大类松脂增脂剂的研究进展进行综述,可为进一步研究高效增脂剂提供参考和理论依据.     

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.