樟子松根系分布特征及其生长适应性研究

通过民勤樟子松根系分布及生长调查分析表明 :樟子松根系分布集中 ,在 2 50cm范围内 0～ 2 0cm土壤层次中根量占调查根系总量的 50 %～ 6 0 % ;樟子松生长迅速 ,10龄树年高生长量达 6 0cm ,粗生长量达 1.0cm ,移栽苗木 2～ 3年后可达到原地苗的生长速度 ,樟子松适应性强 ,同时对温度、光照和水分等因子的敏感性较强 ,充足的光照、水分 ,有利于其生长 ,干旱、低温条件下 ,生长速度明显减缓     

敖汉旗沙地樟子松造林试验

为探讨樟子松在敖汉旗沙地的适生能力，进行了樟子松沙地造林试验，结果表明，24年生的樟子松林，表现基本稳定，生长较快，年平均树高生长量达0．22－0．38m，胸径生长量达0．34－0．59cm，比油松和小叶杨的生长量大。调查研究发现，影响樟子松林生长的主要因素是，当地的降水量较低，在干旱年分林分出现水分亏缺；部分地区的土壤下层有白土间层，水分和养分的含量低；有些林分密度偏大，林分出现枯死现象。     

辐射松、马尾松、长叶松与晚松人工林的生长规律比较研究

对九峰试验林场的辐射松、马尾松、长叶松及晚松人工林生长规律的研究结果表明 :长叶松生长最慢 ,而不宜大面积发展 ;辐射松、马尾松与晚松均表现较好 ,且辐射松与晚松材积生长速率高于马尾松 ,至 2 2a后 ,辐射松材积的生长速率将超过晚松 ;辐射松 4a时胸径连年生长量最大 ( 1 85cm) ,树高速生期为 1 2～ 1 6a,材积速生期为 1 4～ 1 7a,数量成熟龄在 40a之后 ;马尾松 4a时胸径连年生长量达最大 ( 1 30cm) ,1 3a树高连年生长量达最大 ( 3 5 0m) ,材积连年生长量 2 8a最高 ( 0 0 1 60 1m3) ,数量成熟龄为 35～ 40a ;晚松胸径连年生长量在第 3年达最大 ( 1 85cm) ,平均生长量 9a时达最大 ( 1 0 8cm) ,树高速生期为 3～ 8a ,材积速生期为4～ 1 5a ,数量成熟龄为 2 5a。     

36个落叶松家系苗生长变异规律研究

对甘肃省小陇山林业实验局林业科学研究所36个家系落叶松苗期（2年生）进行变异分析各家系间存在变异，变异系数在3．0％～29．0％，平均为13．6％。各家系间苗高生长量差异极显著，191号家系苗高生长量最快，为51．5cm，64号家系苗高生长量最慢，为35．2cm，生长最快的191号苗高比生长最慢的苗高快64．3％；通过家系间的选择方法，能够实现落叶松生长的遗传优良选育。     

火炬松干枯型枯梢病损失量调查

通过对正常生长区和发病区火炬松单株材积和当年生新梢生长量调查，经数理统计分析表明，正常生长区和发病区单株材积差异这极显著水平；当年生新梢生长量损失率达87．20％～94．94％，使5～6年生幼林每年每亩材积生长量较正常生长量（0．4～0．72m~3）减少0．35～0．66m~3。     

樟子松换床育苗技术

苗木通过移植,能增加营养面积,改善苗木的通风和光照条件,促进根系生长,是提高苗木质量的技术措施.一、换床育苗的时间春季樟子松二年生以上苗木生长的特点是萌动早.四月中、下旬,当月平均气温达6-8℃时,芽开始萌动.旺盛生长开始早,但高生长时间短,一般只有30-36天.高生长旺期在5月上旬-6月中旬,其中又以5月下旬生长最快,生长量常占年总生长量的60%以     

彰武松无性系早期生长的初步研究

为研究彰武松早期生长特性,对彰武松优树和优良型樟子松进行嫁接对比试验。研究表明,彰武松树高生长量显著地高于优良类型樟子松,１９９５～１９９７年３年彰武松的平均树高生长量是优良类型樟子松的１５６６％;在不同立地条件、不同年份,彰武松的树高生长量也有显著差异;通过对早期生长的彰武松生理指标进行测定,反映出彰武松比樟子松更抗旱。     

10年生柚木胸径分布与生长

通过对幼龄柚木(Tectona grandis L.f)胸径调查和解析,研究其径级、生长量分布及生长变化规律,表明幼龄柚木胸径分布呈正态分布,径级分化程度较小.13 cm径级以下的占39.84％.胸径各生长量级百分比随生长量增高所占百分比下降,年生长量小于0.2 cm的占39.84％,优势木的胸径和胸径年平均生长量是被...     

樟子松种源家系苗木高生长变异规律研究

对林口县青山林场樟子松2年生苗木的高生长变异进行分析的结果表明，种源问种源内都存在丰富的变异，变异系数在21．1％～22．9％之间，平均值为22．3％。3个种源间苗高生长量差异达显著水平。古莲种源高生长较快，十八站种源高生长最差。各种源家系闻家系内存在丰富的变异，变异系数在12．8％～30．1％之间，平均值为19．38％；不同种源生长较快的前3个家系平均值为27．9cm，生长较慢的后3个家系平均值为19．8cm，前者高生长比后者快41％。     

绥中县海滩沙地营造樟子松调查报告

绥中县海滩沙地营造樟子松调查报告韩辉，张怀福（绥中县林业局）绥中１９８３～１９９１年在海滩沙地引种模子松达１０００ｈｍ’，成活率９５％以上，保存率８５％以上，生长很好，胸径年平均生长量稍低于原产地，树高年平均生长量高于或近于原产地，与相同立地条件上的...     

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.