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1.
《中南林业科技大学学报(自然科学版)》2015,(11)
为了解我国森林资源状况,以建国以来森林资源一类清查数据为基础,分析了建国以来我国森林面积、森林蓄积量和森林碳贮量的变化,并估算2020年时的森林状况。结果显示:1)自建国以来,我国森林面积共增加8821万hm2,森林蓄积量共增加66.21亿m3。但各区域增量不均衡,西南地区森林面积和蓄积量增量最大,东北地区森林面积增量最小,华东地区森林蓄积量增量最小。我国未来森林面积增长潜力在北方地区。2)建国以来,我国森林共吸收碳225.32×108 t,其中人工林碳贮量比例由调查初期的5.3%增加到了16.7%,有较大的碳汇潜力。3)2020年时我国森林面积、蓄积量和碳贮量分别可达20 667万hm2、188.37亿m3和344.766 0亿t,采取科学合理的经营措施可增加我国森林碳贮量。 相似文献
2.
文章以甘肃省森林资源连续清查和统计数据为数据基础,采用统计分析的方法,对 40 年来
甘肃省森林资源动态变化进行了分析研究,结果表明：从 1975 年到 2016 年,全省林地面积由 630.87
万 hm2 增加到 1 046.35 万 hm2
,增长 65.9%;有林地面积由 186.83 万 hm2 增加到 263.89 万 hm2
,增长
41.2%;森林面积（含国家特别规定灌木林）由 2006 年的 470.67 万 hm2 增加到 2016 年的 509.73 万 hm2,
增长 8.3%;森林活立木蓄积量由 1.96 亿 m3 增长到 2.84 亿 m3
,增长 45.1%。森林面积蓄积“双增”幅
度较大。全省乔木林每公顷蓄积量由 1975 年的 99.31m3
/ hm2 微降到 2016 年的 95.45 m3
/hm2
,下降 4.1%,
森林质量较低。同时乔木林树种、林龄结构不够合理。采用回归分析预估,到 2035 年和 2050 年,森林
面积分别达到 639.15 万 hm2 和 742.68 万 hm2
,森林覆盖率达到 14.21% 和 16.52%,乔木林蓄积量达到 3.2
亿 m3 和 4.1 亿 m3
,活立木蓄积量达到 3.6 亿 m3 和 4.5 亿 m3。 相似文献
3.
第六次全国森林资源清查及森林资源状况 总被引：26，自引：0，他引：26
国家林业局森林资源管理司 《绿色中国(A版)》2005,(2):10-12
在系统分析第六次(1999年～2003年)森林资源连续清查总体情况的基础上,总结了此次清查的五个特点;从森林资源结构、资源数量、区域分布、资源发展变化等方面揭示了此次资源清查的最新成果;剖析了森林资源发展中存在的问题,并提出了相应措施。清查结果显示:全国林业用地面积2.85亿hm2,森林面积1.75亿hm2,森林覆盖率18.21%,森林蓄积量124.56亿m3;人工林面积0.53亿hm2,蓄积15.05亿m3。 相似文献
4.
天然林的保护与生态环境的安全密不可分,据第5次全国森林资源连续清查结果统计,全国林业用地面积2.63亿hm2,森林面积1.59亿hm2,森林覆盖率为16.55%,活立木总蓄积量为124 .88亿m3.森林蓄积量为112.67亿m3,森林面积列世界第5位.森林蓄积量列第7位,人工林面积居世界第1位.本文在分析我国天然林保护工程的实施与成效的基础上,提出了促进天然林可持续发展的的几点建议. 相似文献
5.
介绍了广东省第四次森林资源二类调查的方法、特点,对主要结果及数据变化进行了分析。与广东省第三次森林资源二类调查数据相比,广东省森林覆盖率增加了3.09个百分点,森林蓄积量增加了18727.49万m3,林业用地面积减少了 37.09万hm2,森林面积增加了 73.49万hm2,调查结果表明广东省森林资源主要数据变化较大,森林质量有所提高,但总体质量仍较低,单位面积森林蓄积量仅为60.57 m3/hm2,森林质量的提升还有较大增长空间,进一步加强森林经营要求十分迫切。 相似文献
6.
俄罗斯的森林资源及森林病虫鼠害状况 总被引：2，自引：0，他引：2
1 森林资源状况俄罗斯是世界上森林资源最为丰富的国家 ,据 1 998年统计 ,其森林面积为7.74 3亿 hm2 ,森林覆被率为 4 5.3%。有林地面积近 1 2亿 hm2 (占世界总量的 2 2 % ) ,一类林地 2 .71 1亿 hm2 ,二类林地 0 .897亿hm2 ,三类林地 8.1 78亿 hm2 。俄罗斯的森林总蓄积量 81 9亿 m3,其中 4 41亿 m3为成过熟林 ( 346亿 m3为针叶林 )。主要树种的木材蓄积量年平均增长 9.70 4亿 m3,单位面积木材蓄积量年平均增长 1 .3m3/hm2 。可供开采的成过熟林蓄积量为 2 34亿 m3,每公顷成过熟林木材蓄积量为 1 37m3,适采林的木材蓄积量为 1 6 7m3。在俄… 相似文献
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9.
樟子松人工林伐前人工更新技术 总被引：1，自引：0，他引：1
1试验地概况第1组试验地面积为3．3hm2，设在北坡，坡度11°的山腹上。上层樟子松人工林1962年营造，林龄32年。从1979年开始共进行过3次抚育问伐，现每公顷保留800株，林分平均胸径19．9cm、平均树高14．8m、蓄积量179．328m3／hm3、郁闭度0．7。第2组试验地面积为2．0hm2，设在北坡，坡度13°的山腹上。上层樟子松人工林1962年营造。从1979年开始进行过3次抚育间伐，现每公顷保留875株，林分平均胸径为17．4cm、平均树高14．5m、蓄积量144．322m3／hm2、郁闲度0．8。对照区设在与第1组试验地同一山腹相同的樟子松人工林内，面积3．0hm2。… 相似文献
10.
西南桦人工林的林分密度研究 总被引：1，自引：0，他引：1
采用"典型抽样"方法,2011年春和2012年春,在德宏州调查了78块20 m×20 m的西南桦人工林样地。通过相关分析,认为林分密度与林分年龄、平均胸径、蓄积量、年平均蓄积生长量显著相关,而与林分平均树高相关不显著。林分密度与林龄等相关指标的回归,以双曲线方程拟合最好。78块西南桦人工林样地的林分密度-林龄回归方程为y-1=0.014 2-0.009 6 x-1,相关系数r=0.336 8。10年生同龄林分18块样地林分密度-平均胸径的相关系数r=0.627 0,其回归方程为y-1=0.082 5-0.851 6 x-1;林分密度-蓄积量的相关系数r=0.663 5,其回归方程为y-1=0.058 3+2.846 6 x-1;林分密度与年平均蓄积生长量的相关系数与蓄积量同值,其回归方程为y-1=0.582 9+28.465 7 x-1。从林分密度随林龄增长的变化规律及与林分平均胸径的相关变化提出,(1)西南桦人工林应提早在3～5年生时进行抚育间伐;(2)采用"低密粗径"的育林方针,以提高西南桦大中径材产出。到20年生主伐时,抚育间伐后的密度则以900～1 050株/hm2最佳;(3)西南桦造林初植密度降到1 665～1 335株/hm2(株行距2 m×3 m～2.5 m×3 m)为宜。 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
15.
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
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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
18.
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
19.
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
20.
《Scandinavian Journal of Forest Research》2012,27(2):166-178
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. 相似文献