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以景宁县千峡湖库区为例,探讨了库区生态公益林建设中存在着公益林资金分配不合理、矛盾纠纷多、林分质量差等问题,提出了核实完善公益林区划界定、加强纠纷调解、实施分类补助等解决对策。 相似文献
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丹江口库区生态公益林建设浅析 总被引：1，自引：0，他引：1
本文就丹江口水库库区生态环境状况进行了调查分析,提出在库区及周边实施以公益林建设为主要内容的生态环境建设的急迫性、必要性,以及今后的建设重点、建设思路和建设措施等。 相似文献
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浙江江山碗窑水库是国家大（二）型水库，其可控制集雨面积212.5km^2，还可引水集雨面积64km^2。其集雨区生态公益林建设直接关系到水库水土保持、森林景观和使用寿命，尤其与库区群众的经济发展、百姓的生活收入休戚相关。从碗窑水库集雨区相关的实际出发，提出了生态与经济发展相协调的生态公益林建设的管理经营模式及经营对策。 相似文献
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对尤溪县境内的闽江支流尤溪河两岸、道路两边及库区周边一重山的生态公益林现状及存在问题进行了分析，提出了对公益林部分林分进行改造的初步规划，探讨了公益林改造的对策，为尤溪县“两沿一环”（即沿高速公路、公路、铁路，沿河，环城区周边一重山）林分改造工程提供参考。 相似文献
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为推动江苏省扬中市省级公益林的有序健康发展，从权属、地类、林种、龄组、树种组成5个方面对扬中市省级公益林培育现状和管护进行分析。结果表明，扬中市省级公益林总面积为569.91hm2；现有公益林权属以集体林为主，占比82.57%；地类以乔木林地为主；林种均为防护林，龄组以近、成熟林为主，占比81%；树种均为阔叶树，主要树种为意杨Populu seuramevicanacv.‘I-214’、旱柳Salix matsudana、樟Cinnamomum camphora等；公益林总体状况良好，管理措施具体，生态效益显著。存在着更新不及时、缺株断垄现象，以及公益林占比不高、管理重视程度不够等问题，在与国土“三调”数据融合时，整体匹配度也只有69.87%。针对这些问题，提出了六项应对措施：(1)推动林地落界，建成最新的公益林数据库；(2)制定林保规划和公益林规划，提升公益林占比；(3)强化公益林抚育，全面提升公益林质量；(4)做实林长制，健全公益林保障机制；(5)开发护林员岗位，强化护林员队伍；(6)拓展补偿渠道，增加公益林生态收益。 相似文献
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潘标志 《中南林业科技大学学报(自然科学版)》2006,26(3)
运用SWOT分析法,论述了生态公益林建设的发展过程,并对生态公益林建设的优势、劣势、机遇与威胁进行系统的分析,正确认识生态公益林建设和保护在社会经济发展的作用和意义；提出了建设好生态公益林必须加大宣传力度、拓展投入渠道、强化政府行为、明确保障措施、建立补偿新机制、建立限制性利用机制等对策措施,进而推进效益补偿的市场化改革,调动生态公益林经营主体积极性,促进福建省生态公益林建设的可持续发展。 相似文献
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Lignin distribution in spruce (Picea abies) determined by mercurization with SEM-EDXA technique 总被引：1，自引：0，他引：1
Summary The lignin distribution between the middle lamella and the cell wall of spruce fibers has been determined by a new technique based on a mercurization of the lignin and a concomitant determination of mercury by the SEM-EDXA technique. The ratio of lignin in the middle lamella at the cell corners to the lignin in the secondary wall was 2.5±0.6 for latewood and 2.4±0.6 for earlywood. This gives a lignin content of 55–58% in the true middle lamella in the cell corners. The reactivity to mercuric acetate of different wood elements was determined in separate experiments. Fractions enriched in ray cells, middle lamella, and compression wood all reacted at the same rate as the whole wood; about one mole of mercury was incorporated per mole of lignin (C9-unit). 相似文献
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Fibril angle of loblolly pine wood as related to specific gravity,growth rate,and distance from pith 总被引：1，自引：0，他引：1
Charles W. McMillin 《Wood Science and Technology》1973,7(4):251-255
Summary Fibril angles were greater for earlywood (avg. 33.4°) than for latewood tracheids (avg. 26.9°). For earlywood, fibril angle did not differ between growth rates when the specific gravity was low (avg. 33.3°). When the specific gravity was high, wood of fast growth had a higher fibril angle (avg. 35.1°) than wood of slow growth (avg. 32.0°). No differences were detected between core, middle, and outer wood. In latewood tracheids, fibril angles were greater in corewood (avg. 28.0°) than in middle or outer wood (avg. 26.3°). For whole wood (a weighted average of earlywood and latewood), fibril angle averaged 30.7° and was greater in corewood (avg. 32.2°) than in middle or outer wood (avg. 29.9°). 相似文献
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Chuan Fang Xianwei Li Jian Zhang Bing Fang Huixia Dong 《Frontiers of Forestry in China》2008,3(2):158-164
A study on the biomass of fine roots and its relationship with water-stable aggregates (WSA) was conducted in two herbaceous
models, triploid Populus tomentosa + Lolium multiflorum (TL) and triploid P. tomentosa + natural grass (TN). Both of the model triploid P. tomentosa stands were four years old converted from agriculture. Unconverted steep slope farmland was used as a control site. Results
showed that the biomass of fine roots (⩽ 1 mm) in different layers varied in the following descending order: upper layer,
middle layer and lower layer, at approximate ratios of 50:30:20. The average annual biomass of fine roots in ryegrass was
twice that of the mixed natural grass-forest land. The total amount of natural grass roots was 4.4 times that of the ryegrass
model. Water-stable aggregates of the upper, middle and lower layers and the unconverted farmland did not show any significant
differences, whereas the amounts of water-stable aggregates of big-particles in the upper and middle layers were much larger
than those of unconverted lands. The amounts of water-stable aggregates of natural grass-forest lands (TN model) were higher
than those of managed grass-forest lands (TL model). Two-way analysis of variance indicated that fine roots (≤ 1 mm) could
significantly enhance water-stable aggregates and total water-stable aggregates. We conclude that the program of converting
agricultural lands to forest-grass lands is an effective way in improving soil anti-erosion capability.
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Translated from Scientia Silvae Sinicae, 2007, 43(5): 24–29 [译自:林业科学] 相似文献
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Kenji Fukuda Yuko Nishiya Masayuki Nakamura Kazuo Suzuki 《Journal of Forest Research》1997,2(2):79-84
Recently, symptoms of decline have been widely observed in Yezo spruce (Picea jezoensis) and Todo fir (Abies sachalinensis) in Hokkaido. In order to clarify the mechanism of decline, the water status of Yezo spruce and Todo fir trees in the Tokyo
University Forest in Hokkaido were investigated. The decline is observed mainly in stands damaged by Typhoon XV of 1981 (D-stands),
but is not observed in undamaged stands (C-stands). Sampled trees in both types of stands were selected, the severity of their
decline estimated, diurnal water potentials measured and water relation parameters such as water potential at turgor-loss
point (
) and osmotic potential at full saturation (
) were estimated by pressure-volume analysis. The diurnal trends of leaf water potential and midday water potential (
) of the sample trees were clearly different between the D-stands and the C-stand. Water stress in trees was much more severe
in the D-stands than in the C-stand.
and
of the declining trees were lower in the D-stands than in the C-stand. However,
and
were not significantly different between declining trees and healthy-looking trees in D-stands. It was concluded that stand-level
water stress, induced by the destruction of the canopy by the typhoon, was associated with the decline symptoms. The measurement
of water relation parameters proved to be useful for diagnosis and prediction of decline at a stand level in this area. 相似文献
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The size and location of silver particles in K-glycerate/AgNO3 impregnated Swedish pine, green wood as well as high temperature dried, have been studied using TEM micrographs.
The diameter of the silver particles was found to be 2–20 nm in the impregnated green wood and as large as 1000 nm (major
axis) for the ellipsoid-shaped silver clusters in the impregnated dried wood. Studying the projected area of the silver particles
in impregnated green wood indicated that there are a lot of particles (40%) in the compound middle lamella with fewer particles
in the S2 (6–8%), S1 (4%) and S3 (2%) layers. The average distance between the silver particles, 50 nm (S2-layer), in impregnated green wood shows that the impregnant is distributed in the cell wall at the microfibrilar level. Experimental
results show that the fastest diffusion path into the cell wall is from the lumen over the pit membrane through the compound
middle lamella and not from the lumen through the secondary wall layer S3.
Received 11 January 1998 相似文献
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L. A. Donaldson 《Wood Science and Technology》1991,25(1):15-24
Summary Lignin distribution in developing tracheids of Pinus radiata was studied throughout the growth' season using quantitative interference microscopy. The pattern of lignification remained constant although the number of lignifying cells varied reaching a maximum in summer. Lignification of the secondary wall of latewood tracheids was incomplete at the onset of winter. Each stage of lignification was preceded by deposition of carbohydrates with lignification of the middle lamella starting after S1 formation and lignification of the secondary wall starting after S3 formation. Lignification of the middle lamella was completed before the start of lignin deposition in the secondary wall. In one of the trees examined, the secondary wall lignified concurrently with the middle lamella and this was associated with a low lignin concentration in the middle lamella of mature cells. The secondary wall reached a mature lignin concentration of 21–22% v/v except in one specimen containing severe compression wood which reached 28% v/v. The cell corner middle lamella reached a mature lignin concentration of 74–87% v/v. 相似文献
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Betula ermanni population was divided into three groups: the upper population (2 000–2 200 m), the middle population (1 700–2 000 m), and
the down population (1 400–1 700 m) in Changbai Mountain. The dynamics ofBetula ermanni populations in subalpine vegetation are studied and the population life table, fecundity schedule, survival curves, age structure,
and fecundity curves were established. The results showed that the, middle population is obviously, the transition from the
upper population to the down population.
This project is supported by Chinese Academy of Science
Responsible editor 相似文献
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Data from a trial of 36 families at Little Wittenham, North Oxford was used to assess growth traits and stem form in common
ash (Fraxinus excelsior, L.). The trial followed a design described by Barnes (Silv Genet 44(2–3):81–88, 1995) as the Breeding Seedling Orchard (BSO).
The objectives of the study were to determine variation in growth and form traits and estimate genetic parameters of families.
Assessments conducted at 3–8 years for height, diameter at breast height (dbh), straightness and forking showed significant
differences (P < 0.05) among families with Guys (19), Settrington (34), Overbury (23) and Grimthorpe (36) being the best performers while
Coleford (3 and 5) Gwynedd (27) and Bacheiddon (32) were the least performers. At the overall level, the additive genetic
coefficient of variation (CVA) ranged between 10.2 and 12.7% for height and 1.5 and 2.1% for dbh. Height had a high genetic correlation (rg = 0.85) with dbh whilst forking had low correlation (rg = 0.25) with height. Estimates of heritability decreased with age from
= 0.62 at 3 years to = 0.30 at 8 years for height while values for dbh decreased from = 0.48 at 4 years to = 0.27 at 8 years. Some genetic gains are possible despite the low genetic variation among families; height had the greatest
potential of genetic gain (12.5% at 8 years). Results suggest that early selection of superior families of Fraxinus excelsior appears to be feasible and it could be possible to achieve simultaneous improvement in both growth and form. 相似文献