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1.
The land-cover/use change dynamics in Manica Province in Mozambique are analysed, based upon interpretation of LANDSAT images, to assess trends and highlight management suggestions considering current policies in place that include the ownership and participation of local communities in natural resources management and the recognition of traditional ownership systems. Applying an object-oriented approach to compare the year 2004 with 1990, one observes that land-cover/use changes are not distributed evenly in the province. A substantial decrease in areas with trees belonging to the ‘miombo ecosystem’ occurred and an increase of cultivated areas. The nature of agriculture is changing from shifting cultivation to more permanent types. These changes are found in prevalence on gentle slopes and close to the road network.  相似文献   

2.
Forest structure and function strongly depend on and concurrently influence environmental conditions.Tree performance is generally governed by its genetics and environment;thus,recent hotspots in this field include tree genotype × environment,phenotype × environment,and functional trait × environment interactions.The editorial,review,and 22 original research articles in this Special Issue, "Tree ecophysiology in the context of climate change",highlight ecophysiological phenomena(e.g.,climate hor...  相似文献   

3.
Woody plants contribute to the stability and productivity of terrestrial ecosystems and are significantly affected by climate change.According to the concept of environmental hormesis,any environmental stressors can cause hormesis,that is,stimulation in low doses and inhibition in high doses.Numerous studies have demonstrated plant hormesis under low doses of various abiotic stressors.However,the hormetic responses of woody plants to abiotic stressors from climate change are insufficiently studi...  相似文献   

4.
In sandy forest with a forest canopy gap for a period of over 30 years, the spruce(Picea mongolica) seedlings were monitored on two 5-m- wide transects from the center of a large gap into the surrounding forest. The farther they were to the far center, the taller grew the seedling and the more is the number of seedling. There were many seedlings under the canopy but almost all seedlings died before they grow up. Along the forest edge, growth of seedlings was temporarily enhanced by lateral penetration of light from the gap. The implications for natural forest regeneration dynamics are discussed. Our results prove that in P mongolica forest a gap disturbance creates a non-uniform environment for regeneration of the species, and determines that the forest was a non-even aged forest.  相似文献   

5.
Landscape pattern change in the upper valley of Min River   总被引:2,自引:0,他引:2  
《林业研究》2005,16(1):31-34,i002
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6.
7.

Context

A strategy widely proposed for increasing the resilience of forests against the impacts of projected climate change is to increase the number of species planted to spread and reduce the risks from a range of biotic and abiotic hazards.

Aims

We tested this strategy in two case study areas in planted conifer forests in New Zealand and Scotland.

Methods

The performance of the major tree species and an alternative was compared: radiata pine and Eucalyptus fastigata in New Zealand and Sitka spruce and Scots pine in Scotland. The process-based model 3-PG2S was used to simulate the effects of projected climate change at the end of this century, with and without CO2 fertilisation, upon productivity and financial returns. The effects of an abiotic hazard and two biotic hazards were considered.

Results

Under the current climate, the major species outperform alternatives in nearly all circumstances. However, with climate change, their relative performance alters. In New Zealand, planting of E. fastigata becomes more attractive particularly when various hazards and elevated CO2 concentrations are considered. In Scotland, Scots pine becomes more attractive than Sitka spruce at lower interest rates.

Conclusions

The major plantation species in both countries are well suited to the current climate, but deployment of alternative species and/or breeds can help to adapt these planted forests to the impacts of climate change.  相似文献   

8.
In a false-time series, the temporal development of cocoa–gliricidia carbon (C) stocks and soil organic carbon (SOC) were investigated in Napu and Palolo Valleys of Central Sulawesi, Indonesia. As a first step, the Functional Branch Analysis (FBA) method was used to develop allometric equations for the above- and below-ground growth of cocoa and gliricidia. FBA resulted in shoot–root ratios of 2.54 and 2.05 for cocoa and gliricidia, respectively. In Napu and Palolo, the trunk diameter and carbon levels per gliricidia tree were always much greater than that of cocoa. The highest aerial carbon levels were attained at year four in Napu (aerial cocoa–gliricidia = 20,745.2 kg C ha−1) and at year five in Palolo (aerial cocoa–gliricidia = 38,857.0 kg C ha−1). After years four or five, however, the reduced stocking density of gliricidia attributed to a loss of aerial C. During the time spans in question, SOC remained fairly stable though slightly decreasing in Napu and slightly increasing in Palolo. The SOC harbored a vastly greater amount of system C (one-half and one-third of SOC in the 0–15 cm stratum in Napu and Palolo, respectively) relative to tree components. Eight years (Napu) or 15 years (Palolo) after conversion of a rainforest to cocoa–gliricidia agroforestry caused an 88% and 87% reduction of aerial C-stocks in Napu and Palolo, respectively.  相似文献   

9.
I~uchonRhodho saChaliDensis A. Bor is perennial herbthst b6longs tO Crassulaceae. It mainly distributes inJapan, KOrea, China and Russian. In China it mainlydiSbout6S at the alhtude Of 1 770-2 500 m in Changbei Moudsin Of Jinn Province and ZhangguangcaiMountain Of Heilontoiang Province. It is typical alpineplant (Wu et al. 1987, Qin 1994, Lu et al. 1995) andalso very imPOtent m6dicinal plant. From 1950s a lotOf reseaus with about RhodiOIa plantS had beendone in RuSSian, Ukraine…  相似文献   

10.
Based on the tree-ring growth characteristics of Erman's birch (Betula ermanii charm.) and the relationships between it and climatic )'actors at elevation of 1950m, the sensitivity of tree lines in Changbai Mountain to climatic factors was assessed. The results indicated tree line forest in Changbai Mountain had an obvious sensitivity to climate factors. However, difference from other study sits is that the main climatic control factor on tree-ring growth was not current growth season temperatures, as might be expected, but previous winter and current March temperature. Although the precipitation in the region was quite abundant, the tree-ring growth was still significantly correlated with the precipitation during previous winter and current spring. Additionally, climatic factors which influenced the Erman's birch growth were not the yearly variables, but seasonal and monthly variables. Therefore, the reported increase in yearly mean temperature and total yearly precipitation since 1980s was not responded by sustained increase in ring widths in recent decades.  相似文献   

11.
12.
Daxing'anling is a key region for forest fire prevention in China.Assessing changes in fire risk in the future under multiple climatic scenarios will contribute to our understanding of the influences of climate change for the region and provide a reference for applying adaptive measures for fire management.This study analyzed the changes in fire weather indices and the fire season under four climate scenarios(RCP2.6,RCP4.5,RCP6.0,RCP8.5)for 2021–2050 using data from five global climate models together with observation data.The results showed that the analog data could project the average state of the climate for a given period but were not effective for simulating extreme weather conditions.Compared with the baseline period(1971–2000),the period 2021–2050 was predicted to have an increase in average temperature of 2.02–2.65 °C and in annual precipitation 25.4–40.3 mm,while the fire weather index(FWI) was predicted to increase by6.2–11.2% and seasonal severity rating(SSR) by5.5–17.2%.The DMC(Duff moisture code),ISI(initial spread index),BUI(build-up index),FWI and SSR were predicted to increase significantly under scenarios RCP4.5,RCP6.0,and RCP8.5.Furthermore,days with high or higher fire danger rating were predicted to be prolonged by 3–6 days,with the change in the southern region being greater under scenarios RCP4.5,RCP6.0,and RCP8.5.  相似文献   

13.
Urban trees provide vital ecosystem services such as mitigating heat island,improving air quality by removing various air pollutants,capturing rainwater,and acting as topsoil carbon storage.The aesthetic value of urban trees is also another feature that has to be considered in the context of urban greening.Classical criteria for the selection of urban trees have to respond to new challenges imposed to the cities in a near future.Global climate change factors increase the harshness of our cities,and thereby the plant resilience to abiotic stresses has also to be seriously considered for planning the urban greening.Red-leafed species,characterized by the permanent presence of foliar anthocyanins,show a greater tolerance to different environmental cues than green-leafed species commonly used in our cities.In addition,red tree species own a great aesthetic value which has been underestimated in the context of urban areas,especially in the harsh Mediterranean cities.In this study,we emphasize the "privilege of being red" from different point of view,in order to drive the attention to the possibility to increase the use of red-leafed species for urban "greening".Some possible negative aspects related to their use are rebutted and the direction of future researches are proposed.  相似文献   

14.
The interest intermediation system has always attracted the attention of forest policy scientists. However, research on this subject has focused on the national level, despite the fact that forest issues are increasingly prominent on international and European agendas, both in the EU and the Pan-European Process on the Protection of Forests in Europe. Accordingly, the impacts of the globalisation and Europeanisation of forest policy and the peculiarities of multi-level policy processes have not been sufficiently taken into account. This article examines how international forest politics and the integration of national actors in the EU multi-level system of joint decision-making affect national actor constellations. To this end, I draw on the advocacy coalition framework to depict the Austrian forest policy network and its actors’ dispute on forest certification, as well as on hypotheses and empirical results of multi-level governance scholars and on my own preliminary results to investigate the likely effects of the evolving EU forest policy. The discussion provides some hypotheses and indications that national forest policy networks might be subject to significant change.  相似文献   

15.
Sodium, potassium, magnesium, calcium and physicochemical parameters were monitored for one year in a mangrove tidal creek near Bragança, North Brazil, to determine their tidally induced and seasonal variations and the main parameters controlling the concentration of these cations. On a daily basis, cation concentrations showed a strong tidal rhythm due to the mixing of estuarine and mangrove waters. Mean concentrations were highest at the end of the dry season (December 1996) and lowest (April 1997) towards the end of the rainy season. Average values over one year were: Na+ = 329± 118mM, K+ = 6.9±2.5mM, Mg++=37 ±14 mM and Ca++= 6.9±2.4mM. Dissolved oxygen concentration was higher during the dry season due to enhanced aquatic primary production, with a maximum daily average value of 8.5mg/L in July 1996, and a minimum value of 4mg/L in June 1997. Cation concentrations were transformed relating them to the respective average values in standard seawater at salinity 35. Although cation concentrations and salinity tightly correlated, this standardization showed that the concentrations of K+, Ca++ and Mg++ did not depend solely on salinity and reflected the seasonal variation in aquatic primary production. It also allowed the discrimination of their sources (marine, riverine and groundwater). Thermodynamic equilibrium calculations indicate that phytoplankton may be regulating the concentration of these cations in the water column indirectly by inducing precipitation through pH increase and directly through metabolic uptake.  相似文献   

16.
Interactions between value-creating activities are vital to increasing product value. Information sharing is a cornerstone of such interactions. For a forest-owning company with the primary objective to be leading in selling roundwood to forest industries, it appears therefore crucial that the sales people within a forest company have up-to-date knowledge about the forest in planning their sales, and that the forest knowledge is presented in a format that is suitable for them. To investigate if this is the case, a study was conducted at Sveaskog, a large Swedish forest-owning company. Semi-structured interviews were conducted with respondents from different levels in the organization. The results show that most sales managers did not directly use the knowledge about the forests when planning their sales; instead, they relied on historical data and had low trust in the knowledge presented in the tactical forest plan. The study pinpoints the organizational obstacles for using forest information in sales planning. These obstacles need to be addressed if more sophisticated information made available through new technology is to be utilized.  相似文献   

17.
The recombinant expression vectorpET43. lb-AFP, which contains full encoding region of a carrot 36 kD antifreeze protein (AFP) gene was constructed. The recombinant was transformed into expression host carrying T7 RNA polymerase gene (DE3 lysogen) and induced by 1 mmol. L-1 IPTG (isopropyl-β-D-thiogalactoside) to express 110 kD polypeptide of AFP fusion protein.The analysis of product solubility revealed that pET43. 1b-AFP was predominately soluble, and the expressed amount reached the maximum after the IPTG treatment for 3 h.  相似文献   

18.
It is believed that European beech (Fagus sylvatica L.) will increase its competitive ability at its northern range margin in Scandinavia due to climate change. In mixed old-growth forests of beech and Norway spruce (Picea abies (L.) Karst.) at Siggaboda nature reserve (southern Sweden), stand structure characteristics were sequentially recorded in the years 2004, 2005 and 2007 as well as growth in stem diameter using tree-coring analyses. Using these measurements, we studied the effects on stand dynamics of an extreme storm event (2005 “Gudrun” hurricane), drought and heat (mid-summer 2006, spring 2007) and subsequent bark beetle attacks on spruce (growing season 2007), overlaid with warming tendencies. The storm, which caused disastrous damage in many stands nearby, had comparatively little impact on the structure of the spruce–beech stand. All together, only 32 trees (19 spruces, 10 beeches, 3 other species) per hectare were thrown or broken mainly in the leeward direction (NE) or impacted by secondary damage by uprooted neighbour trees; this represents 7% of the total tree number and 11% of the growing stock. Diameter and height structure did not change significantly. However, the 2006 drought and the 2007 attack of biotic agents changed the stand structure and composition strongly due to the death of about 19% of the dominating older spruce trees that accounted for 35% of total stand volume. This resulted in a considerable increase in beech’s contribution to stem number (4% increase) and wood volume of the living stand (7% increase). A comparison of diameter growth of beech and spruce during the periods 1894–1949 and 1950–2005 showed a distinct decrease in growth superiority of spruce during the last 50 years. These results support the idea of a northward migration of European beech as a nemoral tree species in Sweden, due to a higher tolerance to the abiotic and biotic threats accompanying climate change and an increased competitive ability compared to boreal tree species Norway spruce.  相似文献   

19.
Jiewei Hao  L.M.Chu 《林业研究》2022,(5):1481-1492
Tropical regions are biodiversity hotspots and are well-suited to explore the potential influence of global climate change on forest ecosystems.Bryophytes have essential ecological functions in tropical forest ecosystems,but knowledge of the potential impact of global warming and possible changes in water availability patterns on terrestrial bryophytes is limited.We transplanted eight terrestrial moss species from two elevations(900 and 500 m) to warmer and drier elevations(500 and 100 m) during...  相似文献   

20.
The dynamic changes of protein polypeptide in endosperms of Gingkgo biloba seeds during seed germination were studied by SDS-PAGE and two-dimensional gel electrophoresis (2-DE). The results showed that 80 kinds of protein spots in endosperms of Gingkgo biloba were clear observed in the 2-DE spectrum. Protein molecular weights were in the range of 26-52kD, and their isoelectric points were in the range of 5.8-7.8. In the course of seed germination, 13 kinds of proteins were degraded, and 13 kinds of proteins were synthesized; 7 kinds of proteins with different molecular weights and isoelectric points of 35kD/pIr.8, 31kD/pIr.8, 29kD/pIr.8, 33kD/pI6.6, 33kD/pI 6.4, 34kD/pI7.7 and 31kD/pI7.7 were identified primarily as vegetative storage proteins (VSPs).  相似文献   

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