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1.
Punning J.-M. Toff T. Tann R. Lukki T. 《Mitigation and Adaptation Strategies for Global Change》1997,2(1):1-17
The study focused on the problem of the response and adaptation of an ecosystem to natural fire in case of greenhouse warming.
The palaeoecological approach was used and reconstructions were made for timeca 6000 years ago, when the human impact in the studied area was absent or very weak and the summer temperatures were about
2.4 degrees higher than at the present time. The palaeoreconstructions were compliled using the charcoal, pollen and diatoms
data from the sediments of a northeast Estonian lake. The results show that forest fires influenced the biota of the lake
mainly through evapotranspiration and the accompanying erosional changes. The impacts of the fire directly to the lake ecosystem
were short-term and the primary diatom association was restored after 10–15 years. The pollen influx was influenced by the
fires mainly through the changes in the openness of the landscape and the composition of the pollen spectra was restored over
a period of 50–60 years. The data demonstrate the high ability of the studied ecosystem to adapt to the impact of natural
fires in the climatic environment comparable with that predicted for the future. 相似文献
2.
L. V. Mukhortova I. N. Bezkorovainaya 《Mitigation and Adaptation Strategies for Global Change》2006,11(1):191-202
The evaluation of biospheric role of the boreal forests in the accumulation of carbon is connected with the evaluation of
organic matter (OM) pool in soils. The research sites were larch forests, they are situated on Nizhne-Tungusskoe Plateau.
Larch forests of feather-moss and lichen types (110 and 380 years old) were formed on 'ochric podbur' soils. Litter stocks
are 3.5–4.5 kg m− 2 with thickness 10–25 cm. Cryomezomorphic northern taiga soils contains 38–73 t (carbon) ha− 1. Pool of fast mineralized OM has average value 38.1 t (carbon) ha− 1, including 20.5 and 6.4 t (Carbon) ha− 1 of labile compounds on surface and in the soil, and 11.2 t (carbon) ha− 1 of mobile OM. Microbial mass reaches 1.78–3.47 t (carbon) ha− 1, its proportion is 3.6–4.9% of the total OM carbon. Zoomass of feather-moss larch forest is 0.20–0.61 * 10− 2, in lichen larch forest −0.01–0.07 * 10− 2 t (carbon) ha− 1. A pool of resistant to biological decomposition and bonded to mineral soil matrix OM is 17.7 t (carbon) ha− 1 and it varies from 18.6 to 29.0 in feather-moss larch forest, and from 6.4 to 17.0 t (carbon) ha− 1 in lichen larch forest. Two-years field experiment has been performed to determine transformation rates of various plant
litter fractions and to clarify the role of soil biota in these processes. The results showed participation of all biota groups
in the decomposition of plant residues caused weight loss of larch-needles and root mortmass. Isolation of organic matter
from all-size invertebrate groups leads to some decrease of decomposition activity. 相似文献
3.
O. F. Malykh L. M. Faleychik 《Mitigation and Adaptation Strategies for Global Change》2006,11(1):291-295
The area covered by forests in the Chita region (Russian Federation – northern ecological region), is currently administered
within the framework of Russian Federation (RF) legislation. Forests that need to be protected in the Chita region because
of their natural significance were identified based on their status and use regime. The possibility of creating a regional
network of “nature-protection forests” as a first step in the implementation of a boreal forest conservation strategy is discussed. 相似文献
4.
The phorid fly, Pseudacteon tricuspis Borgmeier, is an introduced parasitoid of imported fire ants, Solenopsis spp., in the USA. Although the assumption that phorid flies use fire ant alarm pheromones for host location is probably true,
we demonstrated in a previous study the possible involvement of other ant semiochemicals in the response of P. tricuspis to fire ants. This study was conducted to determine the glandular sources and identity of the semiochemicals mediating this
interaction. First, we tested the electroantennogram response of P. tricuspis to extracts of key body parts and glands of workers of the red imported fire ant, S. invicta Buren. The results confirm that the poison (venom) gland/sac is the key source of compounds which elicited strong antennal
activity in P. tricuspis. Follow-up studies were conducted by using a combination of bioassay-guided fractionation and behavioral bioassays to test
the hypothesis that attraction of this parasitoid to fire ants is mediated by venom alkaloids. The results confirm the response
of P. tricuspis to physiologically relevant amounts of the two venom alkaloid fractions (cis and trans alkaloid fractions) of S. invicta. Further analysis by coupled gas chromatography–electroantennogram detection revealed nine venom alkaloid components including
two novel 2,6-dialkylpiperideines that elicited significant antennal activity in P. tricuspis. This is the first demonstration of the role of venom alkaloids of ants as attractants for their natural enemies. We propose
a semiochemical-mediated host location mechanism for P. tricuspis involving both alarm pheromones and venom alkaloids. The ecological significance of these findings, including the attraction
of male P. tricuspis to fire ant venom alkaloids, possibly for mate location, is discussed. 相似文献
5.
Volatiles from leaves or bark of nonhost birch (Betula pendula) and Norway spruce (Picea abies) dramatically reduced the attraction of the bark beetle, Pityogenes bidentatus (Coleoptera: Scolytidae), to their aggregation pheromone components (cis-verbenol and grandisol) in the field. In addition, odors from both the needles and bark of the host Scots pine (Pinus sylvestris) similarly inhibited attraction. Monoterpenes of pine and spruce (α-pinene, β-pinene, terpinolene, and 3-carene) as well
as ethanol, chalcogran and some nonhost green leaf alcohols [(Z)-3-hexen-1-ol, (E)-2-hexen-1-ol, and 1-hexanol], also reduced catches. Collections of volatiles from the field-tested plant tissues indicated
they released monoterpenes in amounts similar to the synthetics that inhibited responses. The various plant and insect sources
of these inhibitory compounds indicate that P. bidentatus bark beetles have evolved several strategies to increase their fitness by avoiding nonhost and unsuitable host trees in a
complex olfactory landscape.
Received: 6 June 2000 / Accepted in revised form: 25 September 2000 相似文献
6.
L. Tacconi P. F. Moore D. Kaimowitz 《Mitigation and Adaptation Strategies for Global Change》2007,12(1):55-66
Fires have attracted interest and generated alarm since the early 1980s. This concern has been particularly evident in tropical
forests of Southeast Asia and the Amazon, but disastrous fires in recent summers in Australia, Europe, and the United States
have drawn worldwide attention.
Concern about forest fires, and related air pollution and biodiversity impacts, led international organisations and northern
countries – such as the Asian Development Bank, the European Union, the Food and Agriculture Organisation, the United Nations
Environment Programme, the World Bank, and the government of Germany – to undertake fire assessments and provide technical
assistance. Nongovernmental organisations, such as the International Union for Conservation of Nature and Natural Resources
and World Wide Fund for Nature, have also devoted increased attention to fires. Aiming at prevention of future fires, 40 fire
projects and missions costing well over US$30 million have worked in Indonesia over the last 20 years. Despite the money and
effort spent on them, fires continue to burn every year. It may appear to some that efforts to address the ‘fire problem’
have not been effective as fires still occur.
There remains a lack of clarity about ‘fire problems’, which has, at times, led to the adoption of policies that may have
negative impacts on livelihoods, the environment, and the economy. Two ‘simple’ changes in the way fires are considered would
significantly improve fire-related policies and initiatives.
These two points are discussed in the context of Southeast Asia, and particularly Indonesia, as an example of the problems
and questions faced by tropical countries. We argue that efforts on fires so far have generated increased knowledge of the
’fire problem’; now, we need to capitalize on that knowledge to avoid wasting money in the future. 相似文献
• | Fires should be seen as a component of land management processes, rather than as a ‘problem’ to be prevented, suppressed, or mitigated. |
• | Not all fires are the same. |
7.
采用盆栽实验考察了湖泊疏浚底泥和河道疏浚底泥不同利用方式下对土壤基底性质的改良进而促进水生植物芦苇快速定植扩繁效果.试验结果表明,湖泊底泥在竹炭改良利用方式下(L-A实验组)可提高芦苇单位面积分蘖数增长率,最高可达(3.06±0.36) m~(-2)·d~(-1),在与绿化土壤混合利用方式下(L-M实验组)可提高芦苇株高,最高达(155.5±0.7) cm;而河道底泥在与绿化土壤混合利用方式下(R-M实验组)芦苇的单位面积分蘖数增长率和株高效果最优,分别可达(4.76±0.18) m~(-2)·d~(-1)和(139.5±3.5) cm.分析原因发现,施加底泥可以明显降低土壤容重,并提高有机质和磷含量,从而促进芦苇分蘖数增长率的提高.基底微生物群落多样性和群落中Micrococcaceae(微球菌)的丰度也显著提高,进一步证实了施加底泥可以改良基底理化性质从而促进芦苇快速定植. 相似文献
8.
Vulnerability of land systems to fire: Interactions among humans,climate, the atmosphere,and ecosystems 总被引:3,自引:0,他引:3
Sandra Lavorel Mike D. Flannigan Eric F. Lambin Mary C. Scholes 《Mitigation and Adaptation Strategies for Global Change》2007,12(1):33-53
Fires are critical elements in the Earth System, linking climate, humans, and vegetation. With 200–500 Mha burnt annually,
fire disturbs a greater area over a wider variety of biomes than any other natural disturbance. Fire ignition, propagation,
and impacts depend on the interactions among climate, vegetation structure, and land use on local to regional scales. Therefore,
fires and their effects on terrestrial ecosystems are highly sensitive to global change. Fires can cause dramatic changes
in the structure and functioning of ecosystems. They have significant impacts on the atmosphere and biogeochemical cycles.
By contributing significantly to greenhouse gas (e.g., with the release of 1.7–4.1 Pg of carbon per year) and aerosol emissions,
and modifying surface properties, they affect not only vegetation but also climate. Fires also modify the provision of a variety
of ecosystem services such as carbon sequestration, soil fertility, grazing value, biodiversity, and tourism, and can hence
trigger land use change. Fires must therefore be included in global and regional assessments of vulnerability to global change.
Fundamental understanding of vulnerability of land systems to fire is required to advise management and policy. Assessing
regional vulnerabilities resulting from biophysical and human consequences of changed fire regimes under global change scenarios
requires an integrated approach. Here we present a generic conceptual framework for such integrated, multidisciplinary studies.
The framework is structured around three interacting (partially nested) subsystems whose contribute to vulnerability. The
first subsystem describes the controls on fire regimes (exposure). A first feedback subsystem links fire regimes to atmospheric
and climate dynamics within the Earth System (sensitivity), while the second feedback subsystem links changes in fire regimes
to changes in the provision of ecological services and to their consequences for human systems (adaptability). We then briefly
illustrate how the framework can be applied to two regional cases with contrasting ecological and human context: boreal forests
of northern America and African savannahs. 相似文献
9.
西藏色季拉山两种典型天然林分土壤活性有机碳组分与土壤呼吸特征研究 总被引:6,自引:0,他引:6
森林土壤活性有机碳和土壤呼吸及其组分区异是森林土壤碳循环过程研究的关键问题.青藏高原亚高山原始森林植被是我国重要的生态屏障,对全球陆地生态系统的碳收支平衡具有举足轻重的作用.本研究选取西藏色季拉山两种最典型的天然林分(急尖长苞冷杉和林芝云杉)为研究对象,测定了这两种林分的土壤活性有机碳含量和同期的土壤呼吸速率及其组分速率,分析了土壤呼吸及其组分与土壤活性有机碳组分之间的关系,结果表明,西藏色季拉山两种天然林分土壤总有机碳(TOC)、土壤颗粒有机碳(POC)、易氧化有机碳(LOC)和微生物量碳(MBC)含量均具有显著的表聚性.急尖长苞冷杉林土壤活性有机碳含量较高,其TOC、POC、LOC、MBC含量分别为57.05 g·kg-1、17.9 g·kg-1、12.2 g·kg-1和365.6 mg·kg-1.两种林分的土壤总呼吸速率(Rt)和微生物呼吸速率(Rh)差异不显著(p0.05),但它们与枯枝落叶呼吸速率(Rl)和根系呼吸速率(Rr)差异极显著(p0.01),同时,Rl和Rr之间差异极显著(p0.01).从不同林分来看,林芝云杉林的土壤总呼吸速率(Rt)和微生物呼吸速率(Rh)高,而急尖长苞冷杉林的枯枝落叶呼吸速率(Rl)和根系呼吸速率(Rr)高.两种林分土壤呼吸各组分对土壤总呼吸速率(Rt)的贡献率大小依次为:RhRlRr.两种林分均表现为微生物呼吸对总呼吸的贡献比例最高,林芝云杉为92.42%,冷杉为70.81%.两种林分的土壤活性碳组分与土壤呼吸关系最密切的是MBC,其次是LOC,最不密切的是POC. 相似文献
10.
R. D. Lasco M. M. Cardinoza 《Mitigation and Adaptation Strategies for Global Change》2007,12(2):243-257
Climate change is one of the most pressing environmental problems humanity is facing today. Forest ecosystems serve as a source
or sink of greenhouse gases, primarily CO2. With support from the Canadian Climate Change Fund, the Community-based Natural Resource Management for Carbon Sequestration
project in East Timor (CBNRM-ET) was implemented to “maintain carbon (C) stocks and increase C sequestration through the development
of community-based resource management systems that will simultaneously improve livelihood security”. Project sites were in
the Laclubar and Remexio Sub-districts of the Laclo watershed. The objective of this study was to quantify baseline C stocks
and sequestration benefits of project components (reforestation with fast-growing species, primarily Casuarina equisetifolia, and agroforestry involving integration of Paraserianthes falcataria). Field measurements show that mature stands (≥30 years) of P. falcataria and C. equisetifolia contain up to 200 Mg C ha−1 in above ground biomass, indicating the vast potential of project sites to sequester carbon. Baseline C stocks in above ground
biomass were very low in both Laclubar (6.2 Mg C ha−1 for reforestation sites and 5.2 Mg C ha−1 for agroforestry sites and Remexio (3.0 Mg C ha−1 for reforestation and 2.5 Mg C ha−1 for agroforestry). Baseline soil organic C levels were much higher reaching up to 160 Mg C ha−1 in Laclubar and 70 Mg C ha−1 in Remexio. For the next 25 years, it is projected that 137 671 Mg C and 84 621 Mg C will be sequestered under high- and
low C stock scenarios, respectively. 相似文献
11.
Vladimir Stolbovoi 《Mitigation and Adaptation Strategies for Global Change》2006,11(1):203-222
The 50% variation in the estimates of carbon (C) content in the forest soils of Russia at present is caused by confusion of
terms and ignorance of the soil geographical representativeness in forests. The GIS-based analysis closes the gap to the estimate
published earlier by Alexeyev and Birdsey (1994, p. 170). The average soil carbon density (SCD) for the 0.3 meter (m) layer
of the forest soils in Russia is about 8.1 kg C m−2; the 1 m layer captures some 11.4 kg C m−2; and the 2 m layer holds nearly 12.3 kg C m− 2. The mass of C is about 61.6 Pg C concentrated in the 0.3 m layer of forest soils; the 1 m layer accumulates 87.6 Pg C and
the 2 m layer holds about 94.1 Pg C. The C content in soils of the forest zone is much higher for Russia. The SCD is 18.8
kg C m− 2 and the soil C pool (SCP) is 223.6 Pg C in 1 m layer. Peat soils contribute a considerable portion of C to the forest zone
of the country. The cold climate, permafrost and vegetation residues that are rich in recalcitrant compounds support a high
accumulation rate of organic matter and associated nutrients in soils. This conservation is a mechanism to keep the production
potential of the boreal ecosystems high in spite of their relatively low actual productivity in present environments. 相似文献
12.
Potential of Co2 emission reductions by carbonizing biomass waste from industrial tree plantation in South Sumatra,Indonesia 总被引:4,自引:2,他引:4
Okimori Yasuyuki Ogawa Makoto Takahashi Fumio 《Mitigation and Adaptation Strategies for Global Change》2003,8(3):261-280
Approximately half of the carbon in trees can be fixed to charcoal by carbonization. Porous charcoal is useful as a soil amendment
for crop fields and forests, and also as a water purifying agent. Given these facts, charcoal production should be recognized
as one of the most promising CO2 sequestration methods. A project on biomass utilization and forest conservation is proposed as a Clean Development Mechanism
(CDM) project, by incorporating the carbonization of biomass residue and waste from tree plantations and pulp mills, and also
the utilization of carbon products in various fields. A feasibility study was conducted with the existing project of an industrial
tree plantation and pulp production in Indonesia. If conventional charcoal-making methods are used, a total of 368,000 t yr-1 of biomass residue and waste could be transformed into charcoal of77,000 t yr-1, and the carbon emission reductions by the project reaches 62,000t-C yr-1 (or 230,000 t-CO2yr-1) in consideration of the project baseline. This charcoal project could provide jobs for approximately 2,600people. The soil
fertility in man-made forests could be maintained by returning charcoal to the original forests. Therefore, the project would
be beneficial to the regional economy. In addition, the present charcoal project is expected to give more positive impacts
than negative ones, or leakage, beyond the project boundary.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
13.
Dou Junfeng Luo Guyuan Liu Xiang 《Frontiers of Environmental Science & Engineering in China》2007,1(2):233-239
Enhanced biological phosphorus removal (EBPR) is a commonly used and sustainable method for phosphorus removal from wastewater.
Poly-β-hydroxybutyrate (PHB), polyphosphate, and glycogen are three kinds of intracellular storage polymers in phosphorus accumulation
organisms. The variation of these polymers under different conditions has an apparent influence on anaerobic phosphorus release,
which is very important for controlling the performance of EBPR. To obtain the mechanism and kinetic character of anaerobic
phosphorus release, a series of batch experiments were performed using the excessively aerated sludge from the aerobic unit
of the biological phosphorus removal system in this study. The results showed that the volatile suspended solid (VSS) had
an increasing trend, while the mixed liquid suspended sludge (MLSS) and ashes were reduced during the anaerobic phosphorus
release process. The interruption of anaerobic HAc-uptake and phosphorus-release occurs when the glycogen in the phosphorus-accumulating-organisms
is exhausted. Under the condition of lower initial HAc-COD, HAc became the limiting factor after some time for anaerobic HAc
uptake. Under the condition of higher initial HAc-COD, HAc uptake was stopped because of the depletion of glycogen in the
microorganisms. The mean ratio of Δρ
P/Δρ
PHB, Δρ
GLY/Δρ
PHB, Δρ
P/ΔCOD, was 0.48, 0.50, 0.44, and 0.92, respectively, which was nearly the same as the theoretical value. The calibrated kinetic
parameters of the HAc-uptake and phosphorus-release model were evaluated as follows: Q
HAc,max was 164 mg/(g · h), Q
P,max was 69.9 mg/(g · h), K
gly was 0.005, and KCOD was 3 mg/L. An apparently linear correlation was observed between the ratio of Δρ
P/ΔCOD and pH of the solution, and the equation between them was obtained in this study.
Translated from Acta Scientiae Circumstantiae, 2005, 25(9), 1164–1169 [译自: 环境科学学报] 相似文献
14.
In central Mexico, it is common for farmers to retain useful trees in abandoned lands after maize cultivation, creating a park-like landscape of scattered trees for extensive livestock grazing, among other land uses (mature forests, secondary forests, and livestock grazing in secondary forests). Among these trees Acacia cochliancantha and Ipomoea arborescens are the most common species associated with this land use in the region. The objective of this study was to assess the effects of both tree species on soil N and P recycling. To this end, we measured N and P concentrations in leaves of both species; and the seasonal N and P (total and dissolved) content in the litter, and total N and P, inorganic N, and bicarbonate-extractable-P concentrations, and the N transformations in the soil, in samples collected under crown of Acacia and Ipomoea and in open areas. Trees of different species varied in their capacity to cycle N. The leaves of Acacia were richer in N than those of Ipomoea (29.7 and 25.0 mg N g−1, respectively), and nutrient resorption was higher in leguminous trees than in Ipomoea (by 20% in the case of N, and 35% in the case of P). Acacia trees had higher effects on soils than Ipomoea trees, like consistent increases of N concentrations (by 30% in the case of total N, and by 50% in the case of inorganic N) and transformations (N mineralization and nitrification in rainy season increases by a factor of 20 and 36, respectively). On the other hand, Ipomoea produced senescent leaves and accumulated forest litter with less P concentration (0.8 and 0.7 mg P g−1, respectively) in relation to Acacia (senescent leaves: 1.3 mg P g−1; litter: 1.1 mg P g−1), reflecting the lower availability of the nutrient in the soil. The total litter N and P pools decreased in the rainy season under crown of both species, as the dissolved P pool did. The total soil N and P concentrations did not change with sampling season. However, potential N transformations and bicarbonate P under both species were higher in dry season than in rainy season samples. Comparison with other land uses in the region suggests that the Acacia–Ipomoea system cycles low quantity of nutrients, but there are no notable differences in the availability of P in the soils. These results demonstrate that scattered trees improve the N and P cycling following the discontinuation of agricultural practices, and the effects will vary depending on the tree species. 相似文献
15.
3种典型多孔高温改性固废材料对磺胺二甲嘧啶的吸附特性 总被引:1,自引:1,他引:0
以畜禽粪便、农作物秸秆和采煤废弃物这3种典型多孔固体废料为原料,用低氧控温炭化法制成牛粪炭和秸秆炭以及用煅烧后的煤矸石炭对磺胺二甲嘧啶(SMZ)进行批处理吸附实验.通过吸附动力学和等温吸附平衡研究牛粪炭、秸秆炭和煤矸石炭对SMZ的吸附特性,并结合FE-SEM、 FT-IR、 Boehm滴定、 BET及Zeta电位滴定分析表征手段探讨了其吸附机制.结果表明, 3种炭材料对SMZ的吸附在24 h时基本达到平衡. 3种炭材料对SMZ的吸附动力学均符合准二级动力学方程,R~2在0.996 8~0.999 9之间,吸附速率随着炭材料表面有效吸附位点的减少而减小.吸附过程主要由膜扩散、颗粒内扩散和平衡阶段这3个步骤组成,颗粒内扩散和膜扩散共同控制吸附速率.等温吸附数据更符合Freundlich模型,R~2在0.987 4~0.999 7之间,主要为物理吸附,是自发的放热反应. 3种炭材料的最大吸附量依次为牛粪炭(19.64 mg·g~(-1))煤矸石炭(12.06 mg·g~(-1))秸秆炭(9.16 mg·g~(-1)).SMZ在3种炭材料上的吸附机制主要有:分子间的氢键作用、多分子层的表面静电吸附作用和孔隙填充等.其中,静电吸附为主要吸附机制.牛粪炭吸附性能最佳可能是由于其具有较为丰富的含氧官能团、较多的负电荷和较大的比表面积和孔容. 相似文献
16.
E. N. Valendik J. C. Brissette Ye. K. Kisilyakhov R. J. Lasko S. V. Verkhovets S. T. Eubanks I. V. Kosov A. Yu. Lantukh 《Mitigation and Adaptation Strategies for Global Change》2006,11(4):883-896
Mechanical treatment and prescribed fire were used to restore a mixed conifer stand (Picea-Abies-Pinus) following mortality from an outbreak of Siberian moth (Dendrolimus superans sibiricus). Moth-killed stands often become dominated by Calamagrostis, a sod-forming grass. The large amount of woody debris and the sod hinder coniferous seedling establishment and development
as well as creating conditions favorable to the establishment and propagation of wildfires. Fire has been demonstrated to
be an effective method of reducing woody debris and eliminating sod, but the random nature and timing of wildfires often do
not create conditions favorable for conifer regeneration. Our study was conducted in a mature fir dominated stand that died
during an outbreak 6–8 years previously with most of the dead trees still standing. A bulldozer drove through the stand downing
standing snags in late summer with 15–20 m between passes. Snags knocked down by the bulldozer and additional snag fall throughout
the following winter increased downed dead wood 50–60% and large downed dead wood 80% compared to an adjacent untreated area.
In June, a prescribed fire was set and fuel load consumption averaged 70%. Average soil temperatures during the burn ranged
from 47 ∘C at a depth of 2 cm to 10 ∘C at 10 cm; hot enough to kill the grass. Following treatment, the potential for wildfire was reduced and the area was suitable
for either natural conifer regeneration or planting without further mechanical site preparation. 相似文献
17.
《Environmental Science & Policy》2002,5(4):319-333
This paper describes the results of combining several simple models to assess the changes in plant sensitivity to direct effects of gaseous air pollutants that result from changes in climatic conditions. This research has been carried out within the framework of a project on the integrated assessment of regional air pollution and climate change in Europe (AIR-CLIM). The modulation of plant sensitivity to gaseous pollutants has been studied using a model of stomatal conductance that simulates the flow of water vapor from the atmosphere to the plant interior through the stomata. The model has been applied to Norway spruce (Picea abies L.) and European beech (Fagus sylvatica L.). The critical atmospheric concentration levels for SO2 and NOx adopted in international environmental norms have been modified to maintain in different climate scenarios a concentration level inside the plant equivalent to the critical limit in 1990. These simulated critical concentrations are compared with the predicted atmospheric concentrations. Our work indicates that the response can be very different for the two types of forests and in different regions. In general, climate change sensitivity increases in boreal areas and decreases in temperate areas due to temperature and water stress. If the air pollution levels are in the predicted ranges, the problems are less severe now than in 1990, but the cumulative stress will still be significant. 相似文献
18.
Although turbidite deposits are classically considered to be good reservoir rocks for oil and gas, there are no reports concerning
their source rock potential in the literature. The sediments from the Vallfogona Formation in the South-Eastern Pyrenees present
numerous organic matter-rich levels interbedded in sandstones and coarse turbidite deposits. Two types of organic matter deposits
were differentiated on the basis of organic geochemistry and petrography: type A and type B. Type A was deposited in a carbonate
marine environment under hypersaline conditions as indicated mainly by even/odd n-alkane predominance, pristane and phytane ratio (Pr/Ph) < 1, presence of gammacerane, and trisnorneohopane over trisnorhopane
ratio (Ts/Tm) > 1. Type B was deposited in a more mud-rich marine environment evidenced by the predominance of odd n-alkane, Pr/Ph ≥ 1, Ts/Tm < 1, the absence of gammacerane, similar concentrations of the C27 and C29 regular steranes, and the greater abundance of C27 diasteranes. Turbidite facies can be regarded as an environment where organic matter sedimentation is heterogeneous in type
and amount. This study suggests that turbidite deposits with interbedded organic matter-rich levels may act as a combined
source–reservoir system. 相似文献
19.
Optimizing carbon sequestration in commercial forests by integrating carbon management objectives in wood supply modeling 总被引:2,自引:0,他引:2
Charles P.-A. Bourque Eric T. Neilson Chris Gruenwald Samantha F. Perrin Jason C. Hiltz Yvon A. Blin Geoffrey V. Horsman Matthew S. Parker Christie B. Thorburn Michael M. Corey Fan-rui Meng D. Edwin Swift 《Mitigation and Adaptation Strategies for Global Change》2007,12(7):1253-1275
This paper provides a methodology for generating forest management plans, which explicitly maximize carbon (C) sequestration at the forest-landscape level. This paper takes advantage of concepts first presented in a paper
by Meng et al. (2003; Mitigation Adaptation Strategies Global Change 8:371–403) by integrating C-sequestration objective functions in existing
wood supply models. Carbon-stock calculations performed in WoodstockTM (RemSoft Inc.) are based on C yields generated from volume table data obtained from local Forest Development Survey plots
and a series of wood volume-to-C content conversion factors specified in von Mirbach (2000). The approach is used to investigate the impact of three demonstration forest-management scenarios on the C budget in a
110,000 ha forest in south-central New Brunswick, Canada. Explicit demonstration scenarios addressed include (1) maximizing
timber extraction either by clearcut or selection harvesting for greatest revenue generation, (2) maximizing total C storage
in the forest landscape and in wood products generated from harvesting, and (3) maximizing C storage together with revenue
generation. The level of clearcut harvesting was greatest for scenario 1 (≥15 × 104 m3 of wood and ≥943 ha of land per harvesting period), and least for scenario 2 (=0 m3 per harvesting period) where selection harvesting dominated. Because softwood saw logs were worth more than pulpwood ($60 m−3 vs. $40 m−3) and were strategic to the long-term storage of C, the production of softwood saw logs exceeded the production of pulpwood
in all scenarios. Selection harvesting was generally the preferred harvesting method across scenarios. Only in scenario 1 did levels of clearcut harvesting occasionally exceed those of selection harvesting, mainly in the removal of old, dilapidated
stands early in the simulation (i.e., during periods 1 through 3). Scenario 2 provided the greatest total C-storage increase over 80 years (i.e., 14 × 106 Mg C, or roughly 264 Mg ha−1) at a cost of $111 per Mg C due to lost revenues. Scenarios 3 and 1 produced reduced storage rates of roughly 9 × 106 Mg C and 3 × 106 Mg C, respectively; about 64% and 22% of the total, 80-year C storage calculated in scenario 2. The bulk of the C in scenario 2 was stored in the forest, amounting to about 76% of the total C sequestered. 相似文献