山旱区柠条播种造林技术

整地。荒坡丘陵地(坡度大于30°)主要采取沿等高线布穴挖鱼鳞坑整地方式,规格一般为40cm×20cm×30cm,鱼鳞坑的土埂高20cm。每亩挖穴一般为167～222穴。平坦荒地不需要提前整地,播种时按2m×1.5m或2m×2m的株行距品字形布穴,坑穴规格15cm×15cm×10cm。退耕地在播种的前一年进行全面整地,机耕深度要达到30cm左右。种子的选择和处理。用于造林的柠条种子应选择饱满、均匀、具有光泽且颜色呈黄绿色或米黄色无病虫害的种子,千粒重需要达到35g以上。为了促进发芽、减少鼠害,播前用30℃水浸种12～24小时,捞出后用10%的磷化锌拌种。造林时间。只要…     

西南桦造林密度与林木生长的关系

西南桦不同密度6a的试验结果显示:西南桦属速生树种,人工林初期生长很快,树高生长(1　5年生)达1 22　1 90m,胸径生长(3　6年生)达1 12　2 91cm。密度对树高生长有影响但不显著,而与胸径生长呈显著负相关。最大和最小密度林分间平均胸径相差2 88cm,3m×3m林分比1 5m×2m林分林木生长量高32 3%,比2m×2m林分高28 4%,比2m×3m林分高11 6%;单株材积生长与密度亦呈负相关关系,其关系式可用V=ax-b来表示。而林分蓄积则与密度呈正相关关系,即密度大林分蓄积量高,反之则小。随林龄增长,不同密度林分间蓄积差异逐渐缩小。要培育中大径材的西南桦人工林,造林密度不宜大,可考虑采用2m×3m及3m×3m的株行距。     

巨桉短周期工业用材林培育技术研究

针对不同的土壤类型、整地、造林密度、施肥等栽培、管理措施分析 ,表明栽培巨桉应选择中厚层山地黄壤、整地规格为 6 0cm× 6 0cm× 6 0cm、重施基肥和追肥、造林密度为 16 6 7株 /hm2 ,即株行距为 2m× 3m。在轮伐期为 6～ 8年时 ,其经济效益是同等立地条件下马尾松林分经济效益的 3 5倍。宜在巨桉适生区大力发展     

卵叶海桑的育苗和造林技术

卵叶海桑 (Sonneratiaovata)可适应土壤结实、贫瘠 ,水分较低的残次林地造林。一年四季均可播种。种子发芽期间 ,水分盐度控制 5‰以内 ,幼苗控制 8‰以内 ,随着幼苗的长大逐步提高水分盐度。造林季节 3～ 8月 ,在裸滩造林 ,造林密度 3m× 4m或 4m× 4m ;残次林改造 ,造林密度 4m× 5m ,4m× 6m。     

巨桉短周期工业用材林培育技术研究

针对不同的土壤类型、整地、造林密度、施肥等栽培、管理措施分析,表明栽培巨桉应选择中厚层山地黄壤、整地规格为60cm×60cm×60cm,重施基肥和追肥、造林密度为1667株/hm2,即株行距为2m×3m.在轮伐期为6-8年时,其经济效益是同等立地条件下马尾松林分经济效益的3.5倍.宜在巨桉适生区大力发展.     

江洲滩地杨树造林关键技术研究

通过总结联合国粮农组织援建的“中国东部暖温带杨树丰产林”经验,认为江州滩地杨树造林关键技术是造林时间以11月至翌年2月为宜;缩小植穴口径,深栽80cm后培土至地上50cm,造林选用1、2年生苗,密度可选3m×3m,3m×4m,4m×10m或者4m×4m,造林前需清除芦苇。     

提高油松干旱阳坡造林成活率的新方法

<正>多年的造林实践证明，在干旱地区造林影响树林成活的主要因子是“水”。所以阳坡造林更要考虑到水的作用，从适应树苗生理要求出发，为它的成活生长创造条件。根据这个基本理念，从当前生产实际出发，必须采用新法造林。 1 提前整地蓄水，采用穴状反坡整地 整地规格：长40cm，宽40cm，深30cm，株行距2m×3m，每667m~2 110穴。土块打碎、草根石块拣净，穴缘修筑坚固，使土壤疏松多孔，改善其理化性质。穴面稍向内倾斜15～20度，小地型上把阳坡变为阴坡。整地时间7月15日至8月15     

半干旱地区杨树丰产栽培技术研究

采用正交试验设计,对杨树人工林丰产栽培技术进行8a的试验研究,结果表明:4m×2m小区蓄积最高,4m×4m小区蓄积连年增长量最高;含碳酸盐黑钙土的干旱地区施磷肥最好;整地深度50～60cm为宜;最佳组合为每穴施磷肥150g、4m×2m密度、整地50～60cm。     

秃杉造林技术研究

7年来,对秃杉造林成活率、苗木等级、整地方式、造林密度等方面的研究结果表明,用1年生优质壮苗造林效果最佳,成活率达90%以上,材积增加41～54%;采用带状整地加大穴或全面整地加大穴,材积则增加52～72%;株行距以1.5m×1.5m(初植密度4440株/公顷)生长量最大,材积是其它密度的1.4～9.6倍,经济效益显著,每公顷材积净增值高出其它密度1000元以上。     

石灰岩地区生态公益林营造技术

文章根据广东省石灰岩地区多年的造林实践和试验 ,总结了在石灰岩地区营造生态公益林的技术。适地适树是造林成败的关键 ,任豆、光皮树、菜豆树和湿地松在石灰岩地区造林生长好。造林时要高质量整地 ,最好采用规格不小于 4 0cm× 4 0cm× 30cm的大穴穴垦。采用 1年生壮苗 ,在大寒前后半个月造林。造林后要加强抚育施肥和管护。     

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。     

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.     

Key Habitats in the Norwegian Production Forest: A Case Study

This study investigated the forest history, structural characteristics, the presence of fungal species suggested to indicate ecological continuity in old-growth forest, and the species composition of saproxylic beetles in 30 old forest ''woodland key habitats'' (WKHs), and compared them with production forest in the same age-class in south-eastern Norway. No statistically significant differences in forest characteristics, community of saproxylic beetles or number of red-listed beetles were found between the WKHs and the production forest, probably owing to a combination of profound long-term logging and a lack of will to delineate sufficiently large WKHs in the one area with significantly less forestry impact. The study indicates the advantage of including forest history information in WKH selection where such data exist, and the importance of restoring habitats in heavily exploited forest landscapes.