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1.
The paper analyzed the basic characteristics of fast-growing and high-yield plantation, classified and identified the ecological problems in its development, and finally proposed the basic principles and corresponding technical measures for fast-growing and high-yield plantation ecosystem management based on these problems.  相似文献   

2.
Mature leaves of trees and shrubs from sub-humid tropical regions of Benin (Acioa barteri, Cassia sieberiana, Dialium guineense, Dichrostachys cinerea, Guiera senegalensis, Milletia thonningii, Piliostigma reticulatum) and arid and semiarid regions of Zimbabwe and Niger (Acacia holosericea, A. nilotica, Dichrostachys cinerea, Securidaca longepedunculata, Parinari cuvetelio, Ziziphus mucronata) in Africa, and from sub-tropical region in foot-hills of North-West Humid Himalayan range (Albizia stipulata, Bauhenia variegata, Cedrela toona, Celtis australis, Dendrocalamus hamiltonii, Grewia optiva, Leucocephala leucocephala, Morus alba, Papulus ciliata, Quercus incana, Q. semecarpifolia, Q. glauca, Q. serrata, Q. ilex, Robinia pseudoacacia, Salix tetrasperma) were analysed for crude protein, total phenols (TP), protein precipitation capacity (PPC) and operational activity of tannins (values are as mean ± SE). There was no significant difference in the crude protein values of forages obtained from the Himalayan and African region (15.2 ± 1.16 and 14.1 ± 1.19%, respectively), however the levels of TP and biological value of tannins as PPC were significantly higher for the African forages (TP 15.7 ± 4.27 vs 6.0 ± 1.0%; PPC 327.2 ± 113.6 vs 56 ± 15.9 mg bovine serum albumin precipitated/g). The operational activity of tannins expressed as mg protein precipitated per unit of phenols was also significantly higher in forages from the African regions (1.97 ± 0.47 vs 0.66 ± 0.17). For a small set of leaves from arid and semiarid zones of Middle East (Syria, A. cyanophylla; Israel, A. saligna) and India (Eugenia jambolana, Eucalyptus punctata, Prosopis cineraria and Shorea robusta) TP, PPC and tannin activity were closer to those for the African forages.This revised version was published online in November 2005 with corrections to the Cover Date.  相似文献   

3.
Forest Resources and Environment in China   总被引:1,自引:0,他引:1  
With a vast territory, China is rich in forest resources and diversified environments. The changes in forest resources have a direct bearing on environmental quality. The paper gives a detailed account of the dynamic change in forest resources in China, including the overall process of forest evolution, the status quo and features of the existing forest resources and the development and use of major forest resources. In addition, it analyses the current situation of China's environment and explores the main contributing factors based on the overall environmental situation. In order to achieve sustainable management of forest resources and improve the environment in China, the Chinese government attaches great importance to the protection and development of forest resources as well as environmental development and improvement. The paper gives an overview of the thinking for sustainable forest resource and environmental development in the future and current focus of efforts.  相似文献   

4.
5.
Based on the data from 2002 to 2010, the paper analyzed the situation of timber supply and demand in China, and concluded that supply-demand could be balanced basically if taking accounting of timber import. Based on the data from the Seventh National Forestry Inventory, the potential of providing timber from natural forest and plantation was analyzed. The paper also forecasted the future features and trend of timber supply and demand in China. In the end, strategic measures and technological and policy gua...  相似文献   

6.
Editor's note The 9th session of the general assembly of IUFRO was held atMontreal, Canada on August 5-11, 1990. The Chinese delegationpresent at this conference was headed by Liu Yuhe, the president  相似文献   

7.
China is the most populated country in the world, andits land area is not the largest, especially its cultivatedland is gradually declining with socio-economicdevelopment. In order to meet the demand to grain,vegetable and so on, wasteland must be reclaimed(Zhang Jianfeng, 2004). In China there is a large scaleof salt-affected land, e.g. in Lop Nur 5 000 km2, inTurfan almost the same, in Quidam Basen 20000 km2 (Gong Hongzhu, et al, 1984). Owing toadverse conditions crops growing in salty s…  相似文献   

8.
Scots pine (Pinus sylvestris) and lodgepole pine (Pinus contorta) needle litters were compared in terms of nutrient composition and its change during decomposition. Initial nutrient composition differed between the species, with lodgepole pine needle litter having significantly higher concentrations of P, Mg and Mn. However, no difference was found for concentrations of N, Ca or K. Increases in concentrations of N, P and K during decomposition were significant in both litter types. For Ca the pattern of concentration changes followed a quadratic function as decomposition proceeded. Concentrations of Mg and Mn decreased in lodgepole pine needle litter. In Scots pine litter there was also an initial decrease, but it was followed by an increase in most incubations. For both Mg and Mn, changes in concentrations during decomposition differed significantly between species. In the late decomposition stages, concentrations of Mg and Mn became similar in both litter types. Nutrient concentrations generated by the models were compared with those of the humus (F and H) layer in the stands. The model was quite accurate in predicting concentrations of N and P for both species and the concentration of Mg for lodgepole pine. By contrast, it was not accurate in predicting concentrations of Ca and Mn. Nutrient release was estimated for the two species using both measured litterfall data and long‐term estimates, and regression models were used to predict concentration changes. Rates of release of P, Mg and Mn in the lodgepole pine stands were found to be about twice as high compared with those in Scots pine. Calcium was also released to a greater extent although the difference was not significant.  相似文献   

9.
1 INTRODUCTIONUrban forestry can be viewed as a specialized branchof forestry, which deals with the science and art ofplanting, implementing the greenery in and around urbanand populated area. It includes tree planting in temples,offices, schools, hospitals, homesteads, highways orroads between towns or cities as well as public parksand recreational parks so that it contributes directlyand indirectly to the physical, physiological, sociologicaland economic well being of the communitiesconc…  相似文献   

10.
11.
Photosynthetic Characteristics of Ash and Larch in Mixture and Pure stands   总被引:1,自引:0,他引:1  
IntroductionDuringthepasttwodecades,studieshaverevealedthatgrowingash(Fnainusmandshurica)andlarch(LarlksPP.)togetherinaproperwaycanincreasetheproduc-tivityQfthestandsI"'}'-'].Theyieldimprovementmechanismsattributetotwoaspects,i.e.,theabovegroundandundergr…  相似文献   

12.
1 INTRODUCTIONPaulownia, indigenous to China, is one of the bestfast-growing tree species in China. It belongs toScrophulariaceae family, which was ever consideredto include more than 20 species and varieties. Butactually, some of them were the same species withdifferent names. In 1959, Professor Hu Xiuying hadall these species and varieties regrouped and classifiedthem into 6 species based on the results of previousstudies. They are Paulownia elongata, P. fortunei,P. tomentosa, P. gl…  相似文献   

13.
14.
The fuelbreaks were established in south China from 1950s. With the active work of local communities and state government, the fuelbreaks have been built for 398,000 kilometers. In some areas, fuelbreaks and firebreaks have constructed a network primarily, such as in the provinces of Fujian, Guangdong, Guangxi. The fuelbreaks can prevent forest fire effectively. That has been approved by actual examples and burning tests. The fuelbreaks also benefit the forest ecosystem and environment. This paper makes a review on fuelbreaks research and application in China, discussed present research achievements about fuelbreaks mechanism and its development. In the future, the Chinese government and local communities will increase investment in the construction of firebreaks network with fuelbreaks as focal points.  相似文献   

15.
Quantifying fi ne root(≤ 2.0 mm in diameter) distribution and turnover is essential for accurately estimating forest carbon budgets. However, fi ne root dynamics are poorly understood, possibly because of their inaccessibility. This study quantifi es fi ne root distribution and turnover rates for fi ve representative Chinese temperate forests types. Fine root number, diameter, biomass, necromass, production, mortality, and turnover rates were measured using a minirhizotron over a 12-month period. More than 90% of the fi ne roots were < 0.5 mm in diameter, with thin fi ne roots at shallow layers, and thicker ones in deeper soil layers. The fi ne root dynamics were signifi cantly diff erent among the forest types. Coniferous plantations had fewer fi ne roots, less biomass, necromass, production and mortality but greater average diameters than fi ne roots of broadleaved forests. All traits, except for diameter, decreased along the soil profi le. Fine root numbers and production exhibited a unimodal seasonal pattern with peaks occurring in summer, whereas biomass, necromass and mortality progressivelyincreased over the growing season. The turnover rates of roots < 0.5 mm varied from 0.4 to 1.0 a-1 for the fi ve forest types, 0.5–1.0 a-1 for the soil layers and 0.2–1.1 a-1 for the seasons, with the largest turnover rate at the 0–10 cm depth in summer. The patterns of fi ne root numbers, biomass, necromass, production, mortality, and turnover rates varied with forest types, soil depths, growing season and diameter classes. This study highlights the importance of forest types and diameters in quantifying fi ne root turnover rates.  相似文献   

16.
lntroductionWiIdlifemanagersdesirereIiableindicatorsofnu-tritionaIstatusoffree-rangingunguIatestoassessreIationshipsbetWeenhabitatsandpopuIations.ThenutritionaIconditionofunguIatesisstrongIyaffectedbytheirfOodquality,andasunguIatesreguIarlyexpe-riencenitrogenshortages(White1978IRobbins1983),itispaFticuIarlyimportanttoknowthenitrogenconcentrationoftheirfoodpIants.onecommonmethodofestimatingquaIityofungulatedietsisana-IysisnutritionaIquaIityofforagepIantsgrowinginhabitats.However,indisc…  相似文献   

17.
Forest diseases and pests are perceived as a growing hazard to China economy. It is a common conclusion that the actualities of forest pests in china are no effective measures to the old important pests, some secondary pests are ascending to chief pests, increasing devastation from exotic pests, frequent ecological pest eruption induced by environmental detriment and host-leading diseases to threaten the "Western Development Project "in China, which is the most important economical strategy to China; that inducement of current forest pests results from ecological function loss and dangerous exoticpest intruding, On the basis of these cognitions, we suggest that strategies of management pests to natural forest would be stressed to maintain its innate capacities to adjust pests in virgin forest and resume such function in intermpted one, that to artificial forest would establish self-control in afforestated stands and develop resistant tree varieties and species, especially those in landscape trees. In re  相似文献   

18.
综述了β-石竹烯及其衍生物的活性及合成方法.在活性方面,β-石竹烯作为香料已经被应用于化妆品和食品添加剂中,药理研究表明β-石竹烯具有局麻作用、抗炎作用、驱蚊虫作用、抗焦虑、抗抑郁作用,β-石竹烯醇还应用于镇咳祛痰药物中,石竹烯氧化物具有镇痛和抗炎作用,抗真菌作用,还有细胞毒性等.同时还简单介绍了β-石竹烯及其部分衍生物的合成方法.  相似文献   

19.
IntroductionBreedingofChineseaspen(Populusd8vjdtanaDode)inChinastartedin195O'swhenthefirstcrossingsweremadebyProfessorYiPeizhongin1946attheagriculturecollegeofChinacenter(Yi1955)andXuWeiyingin1954attheChineseforestryresearchinstitute(XuandHuangetal.1956).CrossingwasmadebetweenPOoUPIushOPej8nsiSandPd8vha8na,Pd8VdenaandPsdrionIjDuringtheperiod196o-197o,greatattentionwaspaidtothehybridizationbetWeenPOPulUsgenusorraces(Han1995).Themosteffective,systematicresearchworkbegantodeveIopsin…  相似文献   

20.
The main differenee between Chinese and German green roofs 15 that 80% of the green roofs in Germany are extensive green roofs.In China Extensive Green Roofs are very rare,there are a few trial Projeets, but the advantages of sueh extensive green roofs be- eome more and more elear.Several institutes and orga-- nizations are working on the develoPment of standards regulations.  相似文献   

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