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1.
The aim of this study was to assess the potential of biomass production by short rotation poplar in Romania without constraining agricultural food production. Located in the eastern part of Europe, Romania provides substantial land resources suitable for bioenergy production. The process‐oriented biogeochemical model Landscape DNDC was used in conjunction with the forest‐growth model PSIM to simulate the yield of poplar grown in short‐rotation coppice at different sites in Romania. The model was validated on five sites with different climatic conditions in Central Europe. Using regional site conditions, with climatic parameters and organic carbon content in soil being the most important, the biomass production potential of poplar plantations was simulated for agricultural areas across Romania. Results indicated a mean productivity of 12.2 ± 0.5 t ha?1 year?1 of poplar coppices on arable land in Romania. The highest yields were simulated for lowland areas in the south‐east and west and for the Mures valley, whereas the lowest yields – due to either temperature or water limitations – were found for the mountainous regions, the Danube valley, and the region west of Bucharest. The amount of abandoned arable land in the past 10 years indicates that around 10% of cropping land in production in 1999 (approximately 1 million ha) is available for bioenergy production systems today. Production of poplar grown in short‐rotation coppices on these areas would result in a yield of approximately 10 million tons of wood per year. The energy that can be generated by conversion of poplar short rotation coppice biomass may contribute up to approximately 8% of the national energy demand if these set‐aside areas are used for lignocellulosic bioenergy.  相似文献   

2.
In recent years, our ecological knowledge of tropical dry forests has increased dramatically. However, the functional contributions of whole ecosystem components, such as lichens, remain mostly unknown. In these forests, the abundance of epiphyte crustose lichens is responsible for the characteristic white bark on most woody plants, conspicuous during the dry season, but the amount of resources that the lichen component represents remains unexplored. We estimated lichen biomass in a Mexican tropical dry forest using the bark area of trees, the dry mass of lichens per unit area and the percentage of bark covered by lichens, together with previously known tree densities. The lowest 2.5 m of the forests main trunks contained 188 kg/ha of lichen biomass, with lichens covering 85% of the available bark for trees <12 cm DBH and 38% for trees >12 cm. Total epiphytic lichen biomass was 1.34–1.99 Mg/ha. Lichen biomass represented 61% of the foliar biomass in the forest. To our knowledge, this is the first time that a lichen biomass estimate is provided for an ecosystem in which crustose lichens are the dominant lichen growth form. Crustose lichens are typically considered to contribute little to the total lichen biomass and to be difficult to include in ecological analyses. The high lichen biomass in this ecosystem implies a significant ecological role which so far is unexplored. We suggest the crustose lichen component should not be underestimated a priori in ecological studies, especially in ecosystems with abundant lichen cover.  相似文献   

3.
Aboveground tree biomass of Korean pine (Pinus koraiensis Sieb. et Zucc.) was determined for a natural forest of Korean pine and mixed deciduous trees and seven age classes of plantation forests in central Korea. Regression analyses of the dry weights of stem wood, stem bark, branches, and needles versus diameter at breast height were used to calculate regression equations of the form of log Y = a + b log X. Biomass of Korean pine in the mixed forest was 118 Mg ha(-1), and biomass in the plantations was linearly related to stand age, ranging from 52.3 Mg ha(-1) in 11 to 20-year-old stands to 317.9 Mg ha(-1) in 71 to 80-year-old stands. The proportions of stem wood and stem bark in the total aboveground biomass decreased with stand age while those of branch and needle increased. Specific leaf area of Korean pine ranging from 35.2 to 52.1 cm2 g(-1) was significantly different among crown positions and needle ages; in general, lower crown position and current needles had the greatest surface area per unit dry weight.  相似文献   

4.
Estimates of land use and plant productivity are combined to predict total annual primary production in the UK as 252 million tonnes dry matter (10.5 t ha?1yr?1). Annual above ground production is predicted to be 165 Mt (6.9 t ha?1yr?1). Within these totals, intensive agriculture contributes 60%, productive woodland 8%, natural vegetation 26% and urban vegetation 5%. However, only 25% of total plant production is cropped by man and animals, and most of this is subsequently discarded as wastes and residues. 2112 PJ of organic material is available for fuel without reducing food or fibre production, but since much of this could not be economically collected, 859 PJ is calculated as a more realistic biofuel contribution by the year 2000. After deducting 50% conversion losses, this could save P1 billion (1979 prices) in oil imports. Short rotation energy plantations, forest residues, coppice woodlands, animal and crop wastes, industrial and domestic wastes, catch crops, natural vegetation and urban vegetation all have immediate or short term potential as biofuel sources. Sensitive planning is required to reduce environmental impact, but in some cases more diverse wildlife habitats may be created.  相似文献   

5.
This study develops cost, energy input and carbon emissions for a number of switchgrass supply options. The Integrated Biomass Supply Analysis and Logistics (IBSAL) model developed at Oak Ridge National Laboratory is used to evaluate the delivery systems. Three biomass collection systems: baling, loafing and ensiling are evaluated. The number and operational performance of equipment are specified to complete collection operations within 120 days of harvest after August 1. Bales are stacked and tarped on the farm side. The transport of biomass from the farm side to a biorefinery takes place over a full year cycle, i.e. 365 days. Supply quantities range from 454 to 4540 dry tonnes/day (500-5000 dry tons/day). Delivered costs to a biorefinery with capacity of 1814 dry tonnes/day (2000 dry tons/day) are: 44-47 dollars/dry tonne for delivered bales (round and square); 37 dollars/dry tonne for delivered loafs (size 2.4 m x 3.6 m x 6 m); 40 dollars/dry tonne for chopped biomass; and 48 dollars/dry tonne for ensiled chops. These costs do not include any payment to the farmers or switchgrass farming cost. Based on the data from literature, the switchgrass farming cost can range from 30 to 36 dollars/dry tonne. These costs would be additional to the switchgrass collection and transportation cost. Switchgrass collection is generally less expensive than collection of straw or corn stover because of the assumed high yield of 11 dry tonnes/ha and a denser biomass. Energy consumption for delivery systems at this capacity ranges from 4.8% to 6.3% of the energy content of switchgrass. Additional 1% of the energy content of switchgrass is consumed in its farming. At 1814 dry tonnes/day (2000 dry tons/day) capacity, greenhouse gas emissions ranges from 75 to 100 kg of CO2/dry tonne of switchgrass delivered.  相似文献   

6.
In coppice-with-standards, once a common type of management in Central European lowland forests, selected trees (standards) were left to grow mature among the regularly harvested coppice stools to obtain construction wood. After the underwood was harvested, the forest canopy opened rapidly, giving standard trees an opportunity to benefit from reduced competition. Although this silvicultural system virtually disappeared after WWII, historical management cycles can still be traced in the tree-rings of remaining standards. Our research aims at answering the question whether tree-ring series of standard trees can be used to reconstruct past management practices. The study was carried out on 117 oak standard trees from five sites situated in formerly coppiced calcareous oak-hornbeam and acidophilous oak forests in the Bohemian Karst Protected Landscape Area, Czech Republic. The evaluation was based on the analysis of growth releases representing the response of the standards to coppicing events, and comparison to the archival records of coppice events. Our results showed that coppicing events can be successfully detected by tree-ring analysis, although there are some limitations. Altogether 241 releases were identified (49% of major releases). Large number of releases could be related to historical records, with the major ones giving better results. The overall probability of correct detection (positive predictive power) was 58%, ranging from 50 to 67%, probability for major releases was 78%, ranging from 63 to 100% for different sites. The ability of individual trees to mirror past coppice events was significantly affected by competition from neighboring trees (their number and the sum of distance-weighted basal areas). A dendro-ecological approach to the study of forest management history can serve as an input for current attempts of coppice reintroduction and for conservation purposes.  相似文献   

7.
栓皮栎林的生物量   总被引:9,自引:0,他引:9       下载免费PDF全文
本文对北京西山海拔300米的26年生人工栓皮栎林的生物量作了测定。粮据十株伐倒的标准木分别取得乔木各部分的干重。采用W=a(D2H)b的幂函数方程,获得每公顷土地上的树干重32.16吨,枝条重9.85吨、叶重1.68吨、根重9.95吨。对灌木和草本植物采用收割法作测定:灌木的地上部分每公顷为1.33吨,地下部分为2.3吨;草本植物的地上部分每公顷为0.15吨,地下部分为0.8吨。所以栓皮栎的地上部分总生物量每公顷为45.17吨,地下部分13.05吨,总计58.22吨。  相似文献   

8.
The demand for wood from short rotation coppice (SRC) plantations as a renewable energy source is currently increasing and could affect biodiversity in agricultural areas. The objective was to evaluate the contribution of SRC plantations to phytodiversity in agricultural landscapes assessed as species richness, species–area relationships, Shannon indices, detrended correspondence analysis on species composition, Sørensen similarities, habitat preference proportions, and species proportions found in only one land use. Vegetation surveys were conducted on 12 willow (Salix spp.) and three poplar (Populus spp.) coppice sites as well as on surrounding arable lands, grasslands and forests in central Sweden and northern Germany. SRC plantations were richer in plant species (mean: 30 species per 100 m²) than arable land (10), coniferous forests (13) and mixed forests in Germany (12). Comparing SRC plantations with other land uses, we found lowest similarities in species composition with arable lands, coniferous forests and German mixed forests and highest similarities with marginal grassland strips, grasslands and Swedish mixed forests. Similarity depended on the SRC tree cover: at increased tree cover, SRC plantations became less similar to grasslands but more similar to forests. The SRC plantations were composed of a mixture of grassland (33%), ruderal (24%) and woodland (15%) species. Species abundance in SRC plantations was more heterogeneous than in arable lands. We conclude that SRC plantations form novel habitats leading to different plant species composition compared to conventional land uses. Their landscape‐scale value for phytodiversity changes depending on harvest cycles and over time. As a structural landscape element, SRC plantations contribute positively to phytodiversity in rural areas, especially in land use mosaics where these plantations are admixed to other land uses with dissimilar plant species composition such as arable land, coniferous forest and, at the German sites, also mixed forest.  相似文献   

9.
Tropical forests hold large stores of carbon, yet uncertainty remains regarding their quantitative contribution to the global carbon cycle. One approach to quantifying carbon biomass stores consists in inferring changes from long-term forest inventory plots. Regression models are used to convert inventory data into an estimate of aboveground biomass (AGB). We provide a critical reassessment of the quality and the robustness of these models across tropical forest types, using a large dataset of 2,410 trees ≥ 5 cm diameter, directly harvested in 27 study sites across the tropics. Proportional relationships between aboveground biomass and the product of wood density, trunk cross-sectional area, and total height are constructed. We also develop a regression model involving wood density and stem diameter only. Our models were tested for secondary and old-growth forests, for dry, moist and wet forests, for lowland and montane forests, and for mangrove forests. The most important predictors of AGB of a tree were, in decreasing order of importance, its trunk diameter, wood specific gravity, total height, and forest type (dry, moist, or wet). Overestimates prevailed, giving a bias of 0.5–6.5% when errors were averaged across all stands. Our regression models can be used reliably to predict aboveground tree biomass across a broad range of tropical forests. Because they are based on an unprecedented dataset, these models should improve the quality of tropical biomass estimates, and bring consensus about the contribution of the tropical forest biome and tropical deforestation to the global carbon cycle. Electronic Supplementary Material Supplementary material is available for this article at  相似文献   

10.
Aboveground biomass of tropical rain forest stands in Indonesian Borneo   总被引:3,自引:0,他引:3  
Aboveground plant biomass was examined in a tall virgin tropical lowland evergreen rain forest dominated by Dipterocarpaceae in Sebulu, East Kalimantan, Indonesia, with special reference to the gap-, building- and mature phases of the forest growth cycle. From the records of dimensions of sample trees examined by the stratified clip technique and DBH inventory data of trees in a study plot, the biomass of larger trees (DBH 4.5 cm) was estimated by the allometric correlation method. The biomass of smaller plants (DBH < 4.5 cm) was estimated by harvesting the plants in small quadrat plots. Although large differences were found between aboveground-biomass-estimates in different patches of different growth stages, the aboveground biomass in a 1.0 ha plot was 509 t/ha, and the one-sided LAI was 7.3 ha/ha. These values seem to result from the tall forest architecture with huge emergent trees (over 70 m high) and a moderate packing of plant mass indicated by the basal area value of 38.8 m2/ha for trees with DBH 4.5 cm.This study was financed through a grant to H. Ogawa from the Overseas Scientific Research Funds of the Ministry of Education, Science, and Culture, Tokyo. Sponsorship from the Lembaga Ilumu Pengetahuan Indonesia (LIPI), Jakarta, the Lembaga Biologi National (LBN), Bogor, and the Herbarium Bogoriense, Bogor is gratefully acknowledged. We are also grateful to Drs Soetiyati, M. Rifai, K. Kartawinata, and the staffs of P. T. Kutai Timber Indonesia for their kind support, Dr K. Ogino for his advice and cooperation in field work, and Dr H. Kataoka for providing us with the geological map of Samarinda Province.  相似文献   

11.
Environment and seedling community under isolated trees in pastures are different from those in the open pasture. The effect of the pasture trees on the soil nutrients and on the seedling growth were investigated. Seven isolated trees and eight plots were selected in two pastures of 12-yr and 32-yr old derived from a lowland rain forest with nutrient-rich soil at Los Tuxtlas, Mexico. The soil concentrations of total N, P Bray, K+, Na+, Ca2+ and Mg2+, plus others physical and chemical characteristics, were compared between the pasture trees and the open-pasture. An experiment was done to test the hypothesis that soil from under the pasture trees was better for seedling growth than soil from the open pasture. Seedlings of two native tree species and two domesticated species were grown in soil from the two different sites in a shade-house. The dry weight of the shoot and root/shoot ratio were compared. Only total N, P and Na+ differed slightly in concentrations between the sites, but did not promote more seedling biomass. It seems that the soil at this location is sufficiently nutrient-rich even in the open pastures and over-ride any effect of the pasture trees on nutrient availability.  相似文献   

12.
The lack of capacity to monitor forest carbon stocks in developing countries is undermining global efforts to reduce carbon emissions. Involving local people in monitoring forest carbon stocks could potentially address this capacity gap. This study conducts a complete expert remeasurement of community-led biomass inventories in remote tropical forests of Papua New Guinea. By fully remeasuring and isolating the effects of 4,481 field measurements, we demonstrate that programmes employing local people (non-experts) can produce forest monitoring data as reliable as those produced by scientists (experts). Overall, non-experts reported lower biomass estimates by an average of 9.1%, equivalent to 55.2 fewer tonnes of biomass ha-1, which could have important financial implications for communities. However, there were no significant differences between forest biomass estimates of expert and non-expert, nor were there significant differences in some of the components used to calculate these estimates, such as tree diameter at breast height (DBH), tree counts and plot surface area, but were significant differences between tree heights. At the landscape level, the greatest biomass discrepancies resulted from height measurements (41%) and, unexpectedly, a few large missing trees contributing to a third of the overall discrepancies. We show that 85% of the biomass discrepancies at the tree level were caused by measurement taken on large trees (DBH ≥50cm), even though they consisted of only 14% of the stems. We demonstrate that programmes that engage local people can provide high-quality forest carbon data that could help overcome barriers to reducing forest carbon emissions in developing countries. Nonetheless, community-based monitoring programmes should prioritise reducing errors in the field that lead to the most important discrepancies, notably; overcoming challenges to accurately measure large trees.  相似文献   

13.
Little is known about the habitat requirements of Australian bats; however, this information is needed to make better‐informed decisions when systems are disturbed. This study contrasts the roosting and foraging ecology of the eastern forest bat Vespadelus pumilus (Vespertilionidae), one of Australia’s smallest bats, between two sites of differing disturbance history on the mid‐north coast of New South Wales. Lorne Flora Reserve (182 ha) is primarily old‐growth forest surrounded by regrowth forest and eucalypt plantations, while Swans Crossing is dominated by regrowth and eucalypt plantations established on part of an old dairy farm. A total of 38 bats were tracked during the maternity and mating seasons at the two sites. Roost preferences were determined by comparing trees used as roosts with those randomly available, while foraging bats were triangulated from fixed stations at night. Bats tracked at Lorne Flora Reserve typically roosted in hollows within large, mature trees and showed a strong preference for roosting and foraging (females only) within the Reserve. Lactating females at Swans Crossing roosted in hollows of remnant rainforest trees within a gully and dead eucalypts, while males often roosted in understorey trees (such as Acacia). Dead trees were frequently used as roosts at both sites. Under both disturbance histories, the mean distance of female maternity roosts from creeks was 20 m, indicating that riparian zones provide important roosting habitat for V. pumilus. However, roosts shifted to the mid‐slope prior to winter when bats mate. Retention of mature trees in a variety of topographic locations may allow behavioural adjustments with the seasons. Bats caught in the regrowth forest also foraged there, with foraging ranges averaging just 5.3 ha (n = 10), indicating that regrowth is used by this bat for both foraging and roosting.  相似文献   

14.
Although a large proportion of tropical rain-forest in South-east Asia has been replaced by rubber plantations, there is very little information about the impact of such forest conversion on bat diversity. To address this deficiency, trapping and acoustic monitoring programmes were carried out in Ton Nga Chang and Khao Ban That wildlife sanctuaries in southern Thailand with the purpose of comparing species diversity and activity of understorey insectivorous bats at sites in forest and in nearby monoculture rubber plantations. Insect biomass in both habitats was assessed. Bat species diversity and activity were found to be much lower in rubber plantations than in forested areas and mean insect biomass was determined to be more than twice as high in the latter habitat than in the former. Bats utilising forest were shown to have significantly higher call frequencies but marginally lower wing loadings and aspect ratios than bats found in both habitats. Management strategies to increase biodiversity in rubber plantations are discussed.  相似文献   

15.
 天然侧柏林的种类组成以菊科、禾本科植物最多,豆科、百合科、蔷薇科植物次之。组成天然侧柏林植物生活型,以地面芽和高位芽植物所占比例较大,地下芽植物次之,一年生植物的比例略高于地上芽植物。31年生人工侧柏林以胸径4—5cm、树高3—4m的植株数量最多。侧柏的胸径、树高与茎重、枝条重,叶重、根系重之间具显著相关。以胸径为自变量。树木各部分干重为应变量所获得的优化模型为:茎重(Ws)=169.82D1.92(P<0.001),枝条重(WBr)=28.64D2.41,(P<0.01),叶重(WL)=10D2.82(P<0.001),根系重(WR)=e4.99+0.387D(P<0.001)。由此估算得侧柏林的各器官干重:茎15.56,枝条为6.57,叶5.16,根5.29吨/公顷。乔木层的总生物量为32.58吨/公顷。林下灌木和草本层在生长季中变化明显,9月的总生物量为7.17吨/公顷。人工侧柏林总生物量为39.75吨/公顷,年平均净生产力为1.28吨/公顷。  相似文献   

16.
This paper reports on the tree structure, tree dimension relationships and woody biomass production and removal of a sub-tropical natural forest in the Mamlay watershed of the Sikkim Himalaya. The forest provides fuel, fodder and timber to four villages. Only 11 tree species were found growing in the tree stratum despite the high diversity in the stand (32 tree species). The forest shows good regeneration potential with 5474 seedlings/ha and 1776 saplings/ha, but the population structure revealed a marked paucity of trees of higher diameter classes due to removal of trees of lower diameters. Standing wood biomass of 362 Mg/ha is mainly shared by 4 dominating species in the stand. The boles are removed mainly for timber and fuel purposes and about 22 Mg/ha wood biomass was removed in between 1987–1991. Net Primary productivity of woody biomass of the forest is recorded to be 18 Mg/ha/year. 3.85 Mg/ha of annual woody biomass production was removed in the form of tree boles apart from lopping of branches.  相似文献   

17.
We surveyed lichens in an extensive area of lowland deciduous oak and beech dominated forest under wood pasture management within the New Forest National Park, southern England. This provided the basis for an investigation of factors affecting the species density and composition of epiphytic lichen communities. Fifteen 1 hectare plots were established in the same sites as a parallel invertebrate survey, of which nine were in old growth forest and six in oak plantations of between c. 150 and 300 years old. In each plot 12 trees were identified for sampling and lichens were sampled on four aspects of each trunk. Results at the plot level showed that species density was significantly higher in the old growth woodland plots from those in plantations. Plot age had a significant effect on species on oak but this was not significant for lichen communities on beech. The species density of lichens associated with Trentepohliaceae photobionts on oaks showed a linear positive relationship with increasing plot age while the species density of species with other coccal green Chlorophyta decreased with age of the plot. A major part of the lichenised fungi with Trentepohliaceae photobionts includes indicator and notable species used in conservation evaluation and this component is most affected by fragmentation and isolation of forest sites. The results emphasise the importance of long term connectivity and ecological continuity in this extensive mosaic of lowland deciduous forest.  相似文献   

18.
Recent work on bryophyte diversity in lowland forests of northern South America has suggested the existence of a new type of cloud forest, the ‘tropical lowland cloud forest’ (LCF). LCF occurs in river valleys in hilly areas with high air humidity and morning fog, and is rich in epiphytes. We explored epiphyte abundance and canopy microclimate of LCF in a lowland area (200–400 m asl) near Saül, central French Guiana. We analyzed the vertical distribution of epiphytic cover and biomass on 48 trees, in LCF and in lowland rain forest (LRF) without fog. Trees in LCF had significantly more epiphytic biomass than in LRF; mean total epiphytic biomass in LCF was about 59 g/m2, and 35 g/m2 in LRF. In all height zones on the trees, total epiphyte cover in LCF exceeded that in LRF, with ca 70 percent mean cover in LCF and ca 15 percent in LRF. During both wet and dry seasons, mean diurnal relative air humidity (RH) was higher in LCF than in LRF, and persistence of high RH after sunrise significantly longer in LCF. We suggest that the prolonged availability of high air humidity in LCF and the additional input of liquid water through fog, enhance epiphyte growth in LCF by shortening the desiccation period and lengthening the period of photosynthetic activity of the plants.  相似文献   

19.
The biomass and net primary productivity (NPP) of 5- to 15-year-old Shisham (Dalbergia sissoo Roxb.) forests growing in central Himalaya were estimated. Allometric equations were developed for all above- and below-ground components of trees and shrubs for each stand. Understorey forest floor biomass and litter fall were also estimated in forest stands. The biomass (dry matter), forest floor biomass (standing crop litter), tree litter fall and NPP of trees and shrubs increased with increasing age of the forest stand, whereas the dry matter and herb NPP decreased significantly (P < 0.001) with increasing age of the forest. Total forest biomass and NPP ranged from 58.7 (5-year-old stand) to 136.1 t ha(-1) (15-year-old stand) and 12.6 (5-year-old stand) to 20.3 t ha(-1) year(-1) (15-year-old stand), respectively. Of these values, tree biomass accounted for 85.7 (5-year-old stand) to 90.1% (15-year-old) of total forest biomass, and tree NPP for 72.2 (5-year-old) to 82.3% (15-year-old) of total forest NPP. The biomass accumulation ratio (BAR) of the bole component (bole wood + bole bark) increased with increasing age of the forest stand. The bole BAR was 5.8 (5-year-old stand) to 7.9 (15-year-old stand). However, total BAR of the forest stand ranged from 5.5 (5-year-old) to 7.5 (15-year-old).  相似文献   

20.
In this study, we compared ground-dwelling beetle assemblages (Coleoptera) from a range of different oak fragments and surrounding conifer plantations to evaluate effects of forest size and surrounding matrix habitat in a temperate forest of north China. During 2000, beetles were sampled via pitfall traps within two large oak fragments (ca. 2.0-4.0 ha), two small oak fragments (ca. 0.2-0.4 ha) and two surrounding matrices dom- inated by pine plantations (〉4 ha) in two sites of different aspects. Overall, no significantly negative effects from forest patch size and the surrounding matrix habitat were detected in total species number and abundance of ground-dwelling beetles. However, compared with small oak patches or pine plantations, more species were associated with an affinity for at least one large oak patch of the two aspects. Multivariate regression trees showed that the habitat type better determined the beetle assemblage structure than patch size and aspect, indicating a strong impact of the surrounding matrix. Linear mixed models indicated that species richness and abundance of all ground-dwelling beetles or beetle families showed different responses to the selected environmental variables. Our results suggest that more disturbed sites are significantly poorer in oak forest specialists, which are usually more abundant in large oak fragments and decrease in abundance or disappear in small fragments and surrounding matrix habitats. Thus, it is necessary to preserve a minimum size of forest patch to create conditions characteristic for forest interior, rather than the more difficult task of increasing habitat connectivity.  相似文献   

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