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1.
封山育林是培育森林的一种好形式 总被引：1，自引：0，他引：1
龚辉文 《中南林业调查规划》1992,(1):9-13
封山育林是利用森林演替规律,借助自然力,配合人工营林措施,达到恢复森林目的的一种造林方式。在《1989年——2000年全国造林绿化规划纲要》中明确指出:“十二年规划造林总面积5716.5万公顷,其中人工造林3957.9万公顷,飞播造林616.0万公顷,封山育林1142.6万公顷,年均造林面积476.4万公顷”。封山育林的面积占19.99％,可 相似文献
2.
桐庐县定向封山育林技术措施及成效初报 总被引：1，自引：0，他引：1
桐庐县采取分阶段规划，稳步推进定向封山育林，采用人工造林、无林地封育、伐针留阔人工促进、定株抚育间伐封育类型4种主要模式进行定向封育。经过20多年的定向封育，林分质量得到改善，林分的活立木株数比人工造林（补植）增加近50％，针叶林封育可使蓄积量增长33．7％。同时封山育林有利于形成丰富多样的森林植被类型，改善林分结构，增加地表的有机质，从而改良土壤理化性质，改善生态环境。 相似文献
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桂东县把封山育林作为加速全面绿化,发展高效林业,致富于民的一件大事来抓。从1985年至1998年全县共封山100万亩,今年底新增封山22．3万亩。被国家林业局、省林业厅列为封山育林试点县。据调查,全县森林覆盖率由封山前的55．5％上升到67．3％,森林蓄积量由130万立方米增加到320万立方米。同时,经济效益可观。按过去全县每年人工造林5万亩进度推算,100万亩的封山育林需要20年才能完成;按人工造林每亩用工10个计算,可节省劳动力600多万个;按一般人工造林每亩补助15元计算,需要资金1500万元,而这些年用于封山育林的投资只有301万元… 相似文献
4.
三北防护林体系建设工程1978年在咸阳市实施后,咸阳林业建设逐步向多功能、高效益、科学化方向发展,生态环境得到了极大的改善。三北工程实施以来,全市共完成营造林任务39923万亩,其中人工造林36153万亩,封山育林37万亩,截至2008年底,保存人工造林139万亩,保存率为38％,封山育林在封2．8万亩,全市森林覆盖率从工程实施前的14％,提高到目前的23．5％,增加了95个百分点。 相似文献
5.
东沟小流域全封闭封山育林１５年,累计人工植苗造林５５０ｈｍ＾２,天然更新幼树郁闭成林６０ｈｍ＾２,灌木丛恢复成林４０ｈｍ＾２,人工造林郁闭成林１７６ｈｍ＾２,林地面积比封育增加３９．９％,荒山荒地植被盖度增森林覆盖率由封前的４７．０％增长为７１．８％。 相似文献
6.
《防护林科技》2014,(7):F0004-F0004
四川宝兴县位于四川盆地西部边缘，东邻芦山，西连康定，跨越成都平原与川西高原的过渡带，幅员面积3114km2，是四川西部大熊猫主要生态栖息区。世界第一只大熊猫模式标本即产于宝兴，因此，宝兴被誉为“大熊猫的故乡”。宝兴县实施的天然林资源保护工程、退耕还林工程、野生动植物保护和自然保护区建设工程，使全县森林面积达到193985hm2，其中95％为原始森林，森林覆盖率达70．8％，全县绿化覆盖率81．04％，人工商品林32406hm2，天保工程公益林人工造林16327hm2，封山育林53133hm2，退耕还林3133hm2，配套荒山造林2333hm2，封山育林667hm2，这里生物资源丰富，生物多样性明显，气候湿润，空气清新，环境宜人，空气质量与水质质量达国家Ⅰ级标准。 相似文献
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周至县自然资源十分丰富，森林覆盖率达到67．45％。丰富的森林资源孕育了清纯而久流不断的黑河水资源，使之成为西安市人民供水的生命河。近年来，周至人民举生态建设大旗，为黑河水资源保护做出了重大贡献，已累计人工造林27万亩，封山育林12．16万亩，飞播造林5万余亩，实现了“添林增绿”保水源区生态安全的目标。 相似文献
11.
《Scandinavian Journal of Forest Research》2012,27(5):427-435
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. 相似文献
12.
《Scandinavian Journal of Forest Research》2012,27(3):206-217
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. 相似文献
13.
《Scandinavian Journal of Forest Research》2012,27(1):53-61
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. 相似文献
14.
《Scandinavian Journal of Forest Research》2012,27(1):15-27
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. 相似文献
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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。 相似文献
16.
《Scandinavian Journal of Forest Research》2012,27(2):131-138
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. 相似文献
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《Scandinavian Journal of Forest Research》2012,27(5):472-479
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. 相似文献
19.
Srisuda Thippayarugs Banyong Toomsan Patma Vityakon Viriya Limpinuntana Aran Patanothai Georg Cadisch 《Agroforestry Systems》2008,72(2):137-148
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. 相似文献
20.
A. Rigueiro-Rodríguez M. R. Mosquera-Losada E. Gatica-Trabanini 《Agroforestry Systems》2000,48(3):245-256
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. 相似文献