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1.
The effects of stand stem density (SSD), orientation and distance with respect to shelter trees, and fertilisation on planted
Pinus sylvestris and Picea abies seedlings were examined at two sites, one with a southerly aspect (64°14′N, 19°46′E, 225 m
a.s.l.) and one with a northerly aspect (64°09′N, 19°36′E, 274 m a.s.l.) in boreal forests in Sweden. The damage and growth
were compared at these sites in stands with three SSD’s and different light regimes: uncut forest (SSD 500, ~500 stems/ha),
shelterwood (SSD 150,~150 stems/ha), and clear-cut (SSD, 0 stems). Half of the seedlings were irrigated with fertiliser (10 mM N).
Fertilisation and SSD affected the height growth of P. abies, since fertilised seedlings in SSD 0 grew the most (22.2 cm).
Fertilised seedlings in SSD 0 also generally had the greatest biomass (twigs, leading shoot and needles), even P. sylvestris
seedlings on the North slope, where fertilised and unfertilised pine seedlings in SSD 0 had 62.6 and 39.7 g biomass, respectively.
P. sylvestris increased about 150% in dry mass of leading shoot of the increase of P. abies with equal height growth, when
comparing SSD 150 and SSD 0. The results indicate that the general conditions of the stand have stronger effects on the growth
of planted seedlings than their orientation and distance with respect to the nearest tree and that light requirements cannot
be moderated by fertilisation. We postulate that a system in which forest gaps are formed under a shelterwood could provide
a way to regenerate forests that exploits the beneficial features of both shelter trees and clear-cuts. 相似文献
2.
We have used the mass balance approach for calculating nitrogencritical loads (CL(N)) to avoid eutrophication for Sitka spruceplantation forestry in Wales. The various approaches for assigningvalues to the parameters in the mass balance equation are discussedwith particular reference to the soil nitrogen immobilizationvalue. A CL(N) value of 11 kgN ha1 a1 was calculatedfor an intensively studied site in Wales of Yield Class 14 ona freely draining acid soil. If this site is assumed to representa typical spruce stand, application of the CL(N) value meansthat 97 per cent of the area of coniferous forest in Wales,which is predominantly Sitka spruce, is currently receivingnitrogen deposition in excess of the CL(N). The area of coniferousforest at risk is reduced to 72 per cent if the proposed empiricalCL(N) for managed acidic coniferous forests to prevent ecologicalchanges (1020 kgN ha1 a1) is applied andto 45 per cent if the empirical CL(N) to prevent nitrogen saturation,nitrate leaching and depletion of soil base cations is applied(1025kgN ha1 a1). Irrespective of the choiceof CL(N) values, the implications of critical load exceedanceneed urgent investigation. Available information at presentindicates that the main known consequence of chronic atmosphericnitrogen deposition to coniferous forest ecosystems is enhancednitrate and associated aluminium leaching to freshwaters. Thereis insufficient information regarding the potential adverseeffects of eutrophication of soils and waters and of impactson tree health and production. 相似文献
3.
IntroductionHeilongiiangProvinceisoneoftheIargestforestryregionsinChina,whichisnamedaspreciousregionsofforestsdeposits.Greatamountoftimberandrnanykindsofforestproductshavebeenproducedthere.Thedenseforestshaveprovidednaturaldefenseforthesucceedinghighand's… 相似文献
4.
森林道路对山雀类利用人工鸟巢的影响 总被引:1,自引:0,他引:1
于2002 年11月至2003年6 月间, 在韩国安养首尔大学冠岳植物园(37°25'05"N,126°56' 85"E)阔叶林、针叶林和针阔混交林内研究了森林道路对山雀类利用人工鸟巢的影响。对在人工巢箱中繁殖的山雀类,杂色山雀(Parus varius)、沼泽山雀( P. palustris)和大山雀(P. major)的繁殖对的数量、巢位、窝大小、卵重及卵大小进行了调查。调查结果显示,在 3 个研究区,杂色山雀在森林内部(距离道路 75–150m)的繁殖对数量,比森林边缘(距离道路 0–75 m)多,其窝大小、卵重等尺寸也明显比森林边缘高,但沼泽山雀基本不受森林道路的影响。在人类活动频繁的地区人工巢箱为洞穴鸟类提供良好的繁殖条件。人工鸟巢的设置将有利于这些鸟类的保护和管理。表 3 参 16。 相似文献
5.
The history of scientific forest management in Bangladesh datesback to the nineteenth century with defined forest policiesand laws. Due to various socio-economic and socio-politicalfactors, forest cover of the country reduced drastically andall such policy initiatives proved ineffective. Although traditionalforest management objectives covered a wide range from economicbenefit to ecological stability, these have never been attainedfully. Huge population and limited land area compelled policymakers to think about alternatives to traditional forest management.One alternative, social forestry, was introduced in Bangladeshin early 1980s and has proved to be extremely successful. Whiletraditional forest management resulted in a net loss of forestresource cover, social forestry on the other hand, is playinga vital role in the expansion of forest cover (40 387 ha ofnew forest cover and 48 420 km new strip plantation since themid-1980s) benefiting thousands of poor people. Results showthat during the last four years (20002003) more than23 000 individuals benefited from the final felling of differentsocial forestry plantations (woodlot, agroforestry and stripplantation). This generated a total income of US$ 5.6 millionfor the government and US$ 5.3 million for participants plusUS$ 1.2 million for the Tree Farming Fund a 10 per centdepository reserve to sustain the practice in the long run.Although average individual final returns (US$ 223 person1)are not so attractive, some people got about US$ 5000 to US$8500 from final felling, sufficient to improve their standardof living and social position. Despite the success so far achieved,social forestry in Bangladesh still suffers from various institutionaldeficiencies like organization, skilled manpower, legitimateusufruct rights, peoples' participation from policy to implementationand clear budgetary arrangements. Besides, until now the roleof relevant actors is not well defined in all the steps of socialforestry practice in Bangladesh. Unless the participants aregiven clear legitimate usufruct rights, they will remain scepticaltowards this programme. They should have good and meaningfulaccess from planning to implementation. In the context of institutionaldevelopment, there are governmental policy guidelines and a20-year Master Plan for Bangladesh. Although some steps havebeen partially completed, there is still much to do to complywith forest policy guidelines and the Master Plan. It is shownthat in the last seven years (1995/962001/2002) onlyUS$ 15.41 million a1 has actually been spent againstan allocated sum of US$ 68.37 million a1. Therefore,if the intention is to institutionalize social forestry in Bangladesh,government and policy makers should actively come forward. Otherwisethe full potential of social forestry in Bangladesh will notbecome a reality. 相似文献
6.
Oyen Bernt-Havard; Blom Hans H.; Gjerde Ivar; Myking Tor; Saetersdal Magne; Thunes Karl H. 《Forestry》2006,79(3):319-329
Results from a literature review on pinewood ecology, silviculture,genetics, aspects of history and forest resources of Scots pine(Pinus sylvestris L.) in western Norway are presented. The pinewoodscover 40 per cent of the forested land, 0.31 million ha. Duringthe last 75 years, the area has increased by 17 per cent andthe growing stock has risen from 10 to 34 million m3. The impactof man in previous times was very marked, and has had a significantinfluence on the present forest conditions. The pronounced climaticgradients mixed with the topographic variation fromthe coastal plains via the fjord systems to the high mountains is reflected in rather steep gradients in the pine forestvegetation. Various floristic elements can be distinguished,from oceanic via the suboceanic in the outer islands to thethermophytic, boreonemoral and boreal elements in the innerfjord districts and valleys. The introduction of spruce (Piceaspp.) plantations on 1015 per cent of former native pineforests has not negatively affected the bird fauna at the landscapescale. Although not particular species rich, the pine forestsharbour species usually not found in other forest types. Sofar, most work in the field of silviculture and forest ecologyin the pinewoods of West Norway has been in the form of casestudies. Implications of the results for forestry in the regionare briefly discussed. 相似文献
7.
8.
Laboratory freezing tests were used to determine seasonal changesin the frost hardiness of detached shoots of young trees ofEucalyptus gunnii (from central Tasmania), and E. niphophilaand E. debeuzevillei (snow gums from the SnowyMountains, Australian Capital Territory). The trees were growingat the Bush Estate. No difference was found between the speciesor between seedlots, all of which were from high altitudes nearthe tree line. In midwinter (February) the shoots tolerated 16°Cwithout suffering damage, and many shoots survived temperaturesas low as 18°C to 22°C. This result agreedwith Evans' (1986) observation that some trees within theseseedlots survived temperatures in the range 19°Cto 23°C in field planting during the winter 1981/82.In their native habitats the trees rarely experience temperaturesbelow 20°C. The shoots did not harden appreciably before they experiencedfrosts (in late October/early November) and so may be proneto autumn frost damage. By contrast, they were slow to dehardenin late winter and spring and did not seem prone to spring frostdamage. There were no killing air frosts during the period of this study(winter 1985/6), but many trees died, possibly as a result ofground freezing, producing root injury and/or shoot desiccation.In subalpine regions of Tasmania and the Snowy Mountains theground is covered by snow throughout the winter. Variation in frost hardiness within these hardy seedlots couldbe exploited. 相似文献
9.
Daxing'an Mountains was one of the most important forest areas in China, but it was also an area which was prone to suffering
forest fire. The catastrophic forest fire that occurred in Daxing'an Mountains on May 6, 1987 devastated more than 1.33×106 hm2 of natural forests, which leaded to the formation of some mosaic areas with different burn intensities. Two forest farms
of Tuqiang Forest Bureau (124°05′–122°18′E, 53°34′–52°15′N) were chosen as a typical area to analyze the post-fire landscape
change by drawing and comparing the two digital forest stand maps of 1987 and 2000. The landscape lands of forest were classified
into 12 types: coniferous forest, broadleaf forest, needle-broadleaf mixed forest, shrub, nursery, harvested area, burned
blanks, agricultural land, swamp, water, built-up, grass. The results showed that: 1) The burned blanks was almost restored,
some of them mainly converted into broadleaf forest land during the process of natural restoration, and coniferous forest
land by the artificial reforestation, and the others almost changed into swamp or grass land; 2) The proportion of forest
area increased from 47.6% in 1987 to 81.3% in 2002. Therefore, a few management countermeasures, such as the enhancing people's
consciousness of fire-proofing and constructing species diversity, were put forward for forest sustainable development.
Foundation item: Under the auspices of the National Science Foundation of China (No. 30270225, 40331008) and the Chinese Academy of Sciences
(SCXZY0102).
Biography: KONG Fan-hua (1975-), female, Ph.D. candidate of Hiroshima University in Japan, specialized in Landscape Ecology.
Responsible editor: Zhu Hong 相似文献
10.
1973~2003年中国林业生态足迹的研究 总被引:2,自引:0,他引:2
生态足迹是评价可持续发展能力重要指标之一,该方法自提出以来得到广泛关注和迅速应用。首先,本文分析了中国1973-2003年木材生产、进口和出口情况,结果表明,中国在1973-1995年期间木材生产呈明显波动变化趋势,1995年后呈现连续下降趋势;木材进口在1995年后特别是天然林保护工程实施后呈增长趋势,而木材出口在1995年后呈逐年下降趋势。然后,采用改进的生态足迹方法(即森林可持续产量法与森林实际生产法)计算了中国1973-2003年间的林业生态足迹(包括进口与出口林业生态足迹),分析表明,1978-1988年期间,实际生产法计算林地真实面积小于可持续产量法计算结果,而1989-2003年正相反,上述两种方法的计算结果均大于用全球产量计算的林业生态足迹。说明中国在1978-1988年间森林资源消耗量大于生长量,林业发展是不可持续的;1989年后森林资源消耗出现长大于消的局面,林业朝着可持续的方向发展,但同林业发达国家相比仍有较大的差距。最后,讨论了林业生态足迹与国家重要政策(包括外贸、经济与森林保护政策)的关系,并提出了减少林业生态足迹与增强林业可持续发展能力的几点建议。图3表1参31。 相似文献
11.
Denitrification of an Upland Forest Site 总被引:1,自引:0,他引:1
Rates of nitrogen loss through denitrification were monitoredfor standing forest and adjacent clear-felled areas locatedon a peaty-gley soil at Kershope Forest in the north of England,in two year-long studies. The rates of denitrification in soilcores brought back to the laboratory were determined using theacetylene (C2H2) block technique. An equation relating denitrificationto temperature was applied to derive an estimate for the monthlyloss of nitrogen via denitrification from the sites. In an additional study, half of the cores were incubated inthe absence of C2H2, so that an estimate of the ratio of emissionof N2O/N2 could be made. An annual loss of 13 kg N ha1 y1 was estimatedfor the standing forest while losses from the clearfelled siteswere estimated at 1040 kg N ha1 y1 duringthe first 2 years after felling. This loss returned to pre-fellinglevels 4 years after felling. The results are discussed in relation to other studies of denitrificationin forest soils and to the rates of N2O being lost to the atmosphereby UK forests. 相似文献
12.
Establishing evaluation index system for desertification of Keerqin sandy land with remote sensing data 总被引:2,自引:0,他引:2
科尔沁位于我国东北部,地处东北平原向内蒙古高原的过渡地带(42°41'-45°15'N,118°35'-123°30'E),是受荒漠化影响较重的地区。利用外业调查数据,依据地表形态和生态状况的变化,确定了植被盖度、裸沙地占地百分比和土壤质地3 项评价指标,并建立了基于遥感的科尔沁沙质荒漠化评价指标体系,其中裸沙地占地百分比用混合像元分解的方法获得。利用外业调查的数据对该指标体系进行验证,结果表明该指标体系适于研究区域的荒漠化评价。表4参11。 相似文献
13.
FORESTAR:A decision—support system for multi—objective forest management in Northeast China 总被引:11,自引:0,他引:11
SHAOGuo-fan DAILi-min LIYing-shan LiuYong-min BAIGuang-xin 《林业研究》2003,14(2):141-145
Past monoculture forestry in China has contributed to countrywide ecological disasters and economic difficulties in forestry regions. China‘s new forestry programs, Natural Forest Conservation Program and Returning Farmlands to Forests Program, provide opportunities for ecosystem management of mountain forests in China. A decision support system, FORE-STAR, has been developed for better managing and protecting natural forests in Changbai Mountain area. It uses GIS-based forest inventory data at a scale of forestry bureau. The first version contains two sub-modules: forest operation and forest res-toration. Under each sub-module, users can compare several decision options and make optimal choices. It can help field for-esters, forest managers, and policy makers make multi-objective and consistent decisions in planning forest management at hierarchical administrative scales. 相似文献
14.
- The net annual above ground dry matter production of a 17 yearplantation of Sitka spruce in Scotland was 26.7 t ha1y1.Total annual production which includes estimates for roots,was 35 t ha1y1, one of the highest values reportedfor coniferous forest in the temperate zone.
- When comparedwith other forests with high rates of net productionthis standhad the highest foliage and branch biomass and lowestrate ofproduction per unit of foliage.
- Gross foliage increment tothe canopy declined following thetime of maximum stand basalarea increment, which coincidedwith the onset of competitionbetween individual trees. Thesechanges in canopy and standstructure are discussed in relationto the decline in net productionwhich has been observed inpolestage conifer plantations.
- Foliageand branch production were greatest in the top 6 whorlsof thecanopy; over the period studied new foliage became concentratednearer to the top of the trees. Significant branch wood incrementceased below the height where needle death balances needle production.
- New needles produced at increasing depth in a canopy weighedless per unit needle area. Generally needles lost weight asthey aged. All needles survived for three years, the greatestmortality was of 5-year-old needles but some survived for 8years.
- Needle area index was 1011 at age 16, 78at age18. Branch area index was 3.6 and the ratio of main stembarksurface area to ground area was 0.4 at age 16.
15.
Samples of litter and humus from beneath 10 m tall, closed-canopySitka spruce planted on a brown forest soil were incubated underboth field and laboratory conditions to measure mineral nitrogenproduction and carbon dioxide evolution. Mineral nitrogen productionin enclosed samples over 12 months was equivalent to 50 and17 kg N ha1 in litter and humus, respectively. Applicationsof fertilizer NPK (200 kg N ha1 as ammonium nitrate,100 kg P ha1 as unground rock phosphate and 150 kg Kha1 as potassium chloride), 18 months previously, decreasedthese values slightly, but stimulated the production of nitratein both litter and humus. Compared with samples kept under laboratoryconditions at 10°C, those incubated in the field at a similarmean temperature released less carbon dioxide and, in the caseof fertilized humus produced smaller amounts of mineral nitrogen. 相似文献
16.
Mohammed Alamgir M. Al-Amin 《林业研究》2007,18(3):174-180
The organic carbon storage in trees and organic carbon flow with geoposition of trees was estimated in the forest area of Chittagong (South) Forest Division within geo-position 91°47′ and 92°15′ East longitude and 21°45′ and 22°30′ North latitude. The study was conducted through stratified random sampling by identifying each sampling point through Global Positioning System (GPS). It was found that above ground organic carbon storage (t/hm^2), below ground organic carbon (t/hm^2) and total biomass organic carbon (t/hm^2) was respectively the highest in Dipterocarpus turbinatus (Garjan) (7.9, 1.18 and 9.08 t/hm^2) followed by Tectona grandis (Teak) (5.66, 0.85 and 6.51 t/hm^2), Artocarpus chaplasha (Chapalish) (2.32, 0.34 and 2.66 t/hm^2), Artocarpus lacucha (Batta) (1.97, 0.29 and 2.26 t/hm^2) and Artocarpus heterophyllus (Jackfruit) (1.7,0.25 and 2.26 t/hm^2). From the study it was revealed that organic carbon stock was the highest (142.7 t/hm^2) in the geo-position 22° Latitude and 92° Longitude and was the lowest (4.42 t/hm^2) in the geo-position 21° 50′ Latitude and 92° 2.5′ Longitude. The forest of the study area is a good reservoir of organic carbon so has a good capacity to sequester organic carbon from the atmosphere. Sustainable forest management may help to sequester more organic carbon so that economic benefit for the country and environmental benefit in the international arena are possible from the study area. 相似文献
17.
Larch(Larix olgensis), Manchurian ash(Fraxinus mandshurica), Korean pine(Pinus koraiensis) and White birch(Betula platyphylla) are the major planting species in northeast China. The samples of forest litters were collected from the stands of the above
4 species in Laoyeling and Jianlagou experiment stations of Maorshan Exp. Forest Farm (45°12′–45°30′N, 127°30′–127°48′E),
Northeast Forestry University, in early October 2002. Quantitative analysis and qualitative analysis were carried out on the
organic acids existing in freshly fallen litters (L layer) and hemi-decomposed litters (F layer) of the four forest species
by using Gas Chromatogram system. A wide variety of organic acids were identified, including oxalic, malonic, fumaric, succinic,
maleic, malic, citric, C16:O, C18:O, C18:1, C18:2, C18:3 and C20:O acids. In respect of L litters of all samples, the oxalic acid content (over 30 mg/g) was the highest of the seven low-molecular-weight
organic acids identified, while the content of oleic or linoleic (above 40mg/g) was found to be highest among the six high
aliphatic acids identified. As to F litters, oxalic acid content was also the highest, followed by linoleic and oleic. For
the same tree species or the same forest, the kinds and contents of organic acids in L litters were more abundant than that
in F litters.
Foundation item: This paper is supported by National Natural Science Foundation of China (30170768)
Biography: SONG Jin-feng (1976-), female, doctor postgraduate, Harbin 150040, P. R. China.
Responsible editor: Chai Ruihai 相似文献
18.
Historical forest fire records from Alaska State (1950–2000), California State (1895-2001), USA and Heilongjiang Province
(1980–1999), China were used to calculate the longitude and latitude of the annual burned area’s centroids for these regions.
Fluctuation phenomena by year were analyzed using spectrum analysis. The results show that centroids of burned areas in these
three regions are in a fluctuating condition that encircles the distribution center. The distribution centers are 151.11°W,
64.96°N in Alaska State, 120.02°W, 37.11°N in California State and 127.07°E, 49.59°N in Heilongjiang Province, respectively.
The fluctuation of the burned area’s centroids in Alaska State and California State in longitude has obvious periodicity,
and the periodicities are 4.2 years, 6.25 years in Alaska State and 6.24 years, 106 years in California State. The fluctuation
of the burned area’s centroids in Heilongjiang Province has a periodicity both in longitude and latitude, and the periodicities
are both 3.3 years, 6.67 years. Fluctuation of the burned area’s centroids in Alaska State and California State in latitude
does not have periodicity, and big forest fires with low frequencies predominate.
__________
Translated from Scientia Silvae Sinicae, 2006, 42(5): 89–103 [译自: 林业科学] 相似文献
19.
Stands of clonal Salix viminalis (in 1985) and Populus trichocarpa(in 1986) were grown for one growing season from cuttings incontainers, at 0.3 m spacing, supplied with trickle irrigationand nutrients. Woody biomass production (Bw) in the first yearwas analysed as the product of the proportion of dry matterpartitioned to wood ({macron}), the seasonal mean efficiencywith which intercepted light was used to produce dry matter({macron}), the mean fraction of incident light interceptedby the canopies (f{macron}), and the amount of incoming solarradiation over the season (A). Thus, Bw = {macron}f{macron}{macron}A. For Salix, Bw=10 t ha1y1, while for Populus, Bw= 5 t ha1y1, mainly because of differences in{macron} and f{macron}. The Populus partitioned more dry matterto roots (and correspondingly less to stems) and interceptedless light over the growing season. The Salix and Populus cloneshad surprisingly similar ({macron}) values, namely 1. 58 and1. 50 g MJ1, respectively (based on total dry matterand total solar radiation), which are very like the {macron}values measured on C3 agricultural crops in Britain. Also, theSalix and Populus clones produced canopies with similar lightextinction coefficients and hence similar relationships betweenfractional interception and leaf area index. 相似文献
20.
本文于1981-1984年植物生长季节对四川卧龙自然保护区森林土壤水分状况,进行了定位研究,试验林地设置在1200-4300m海拔高度的不同生物气候带的森林类型下。选择的五处试验林地是:①常绿阔叶林下的山地黄壤;②次生落叶阔叶林下的山地棕壤;③针阔混交林下的山地暗棕壤;④暗针叶林下的山地棕色暗针叶林土;⑤高山草甸植被下的高山草甸土。试验结果阐明了试验林地土壤的蓄水性能,枯枝落叶层最大蓄36-313t/ha,森林土壤的渗透系数在1.54-5.33mm/min,试验林地生长季节森林土壤水分贮量,都在最佳含水量下限以下,试验林地森林土壤水分供给(生态湿度)顺序为:山地棕色暗针叶林土(重湿)>高山草甸土(重温)>山地棕壤(湿)>山地黄壤(较湿)>山地暗棕壤(较湿一潮)。 相似文献