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<正> 当今引起各国学者关注的“agroforestry”,它是现代林一农发展的重要途径之一。“agroforestry”一词在国内有许多译法,如农林业、农业林业、农林业制度,农用林业、林-农复合生态系统等。目前尚无一个统一的名称。我们认为把这种种植形式作为一个系统来对待比较合理,林一农复合生态系统具有复合性,包括农、林、牧、副、渔。这种经营类型有机地结合起来,而形成的一种土地利用、空间和时间序列合理配 相似文献
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在阐述西藏林业发展状况及存在问题的基础上,论述可持续经营对西藏林区森林生态系统和经济建设的重要意义及其迫切性.提出其经营的技术包括以过伐林和次生林的恢复经营措施为主的生态林业示范模式,符合西藏实际的林-农-鱼、林-牧、林-副等复合经营模式. 相似文献
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本文通过对城郊农林复合生态系统含义、原理、管理技术等方面的论述 ,提出建设农、林、牧、副协调发展 ,集高新技术、现代农林业技术、管理技术于一体的多功能城郊农林复合生态系统 ,成为城市森林生态工程的重要组成部分 相似文献
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白杨派树种是林学界目前公认的理想抗光肩星天牛树种。１９９１年以来呼市发生大面积光肩星天牛的危害，直接影响到农牧业及城市建设，现已采伐农防林被害木３００余万株，网眼数千个。为迅速恢复高标准农田林网，实现全市平原绿化达标，从１９９０年起我们在郊区西苗圃和... 相似文献
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本文对混种大豆的落叶松.大豆、水曲柳-大豆复合生态系统土壤理化性质进行研究。结果表明,在一个生长季内混种后的土壤物理性质得到了改善。落叶松.大豆与水曲柳一大豆复合生态系统的土壤容重为1.112g/cm3和1.058g/cm3均低于相对应的纯林:混种大豆后土壤总孔隙度增加。两种林-豆复合生态系统土壤有机质分别比对应纯林高1.77倍和1.09倍:落叶松一大豆复合生态系统全氮和水解氮含量分别高于落叶松纯林4.2%和53.0/%,水曲柳-大豆复合生态系统全氮和水解氮含量分别高于水曲柳纯林75.5%和3.3%:混种大豆后全磷含量降低,而有效磷含量则增加:落叶松-大豆复合生态系统全钾和有效钾比落叶松纯林高0.6%和17.5%,水曲柳-大豆复合生态系统全钾和有效钾分别比水曲柳纯林高56.4%和21.8%。图1表3参27。 相似文献
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林窗效应研究综述 总被引：1，自引：1，他引：0
森林群落常发生一些小规模的内源干扰,从而形成林窗。林窗的形成对推动森林群落的演替更新和生态系统发展至关重要。林窗面积的大小与树木的倒伏方式和林冠冠幅及大小有关。林窗面积及林窗内位置的不同,导致其小气候和土壤理化性质等环境因子发生改变,进而影响到林窗内树种更新和物种组成、林窗植被的物种多样性及其微生物和土壤动物的种类、数量等方面。未来林窗研究重点应该放在次生林和人工林的林窗效应,林窗对森林生态系统碳储量影响机制,林窗凋落物分解因子间的相互关系、作用机理和养分循环,不同树种的林窗与最适更新面积的关系,林窗的边缘效应,林窗的土壤动物和微生物动态及过程。 相似文献
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林农复合系统中池杉根系与林龄对林下农作物生产力影响的初步研究 总被引：1，自引：0，他引：1
江苏里下河滩地过去主要生长芦苇,由于地下水位降低,自然植被芦苇等日趋衰弱,80年代前后,以林-农、林-渔、林-牧等相结合的滩地开发得到迅速发展。黄宝龙等研究了林农复合系统的结构、生态效应、经济效益和配套的工程措施、技术措施等,提出了林农复合经营是较为理想的滩地开发方式,池杉(Taxodium ascendens)是适合的树种,适宜的造林密度为4×1.5m,对林农复合系统的生产力也进行了初步研究,但对复合系统中各组分对农作物生产力的影响探讨较少。本文拟对池杉的根系及林龄对农作物生产力的影响作初步研究。 相似文献
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根据子午岭林区林虫区系组成和区划特征，结合主要树种害虫危害特点，提出了预防和除治子午岭林区森林害虫的3项措施。 相似文献
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采取以线路调查为主,踏查与详查、人工采集与灯诱相结合的方法,对祁连山自然保护区青海云杉林中不同林层的昆虫分别进行了采集调查分析.结果表明祁连山区青海云杉林中植食性昆虫具有明显的垂直分层结构,根据林分的垂直结构和昆虫寄生、取食树木组织部位可划分为6个群落,其种类由多到少依次为灌木和草本层昆虫群落(928种),土壤与根部昆虫群落(约780种),嫩梢与针叶昆虫群落(117种),树干韧皮部与木质部昆虫群落(66种)、枝梢与嫩皮昆虫群落(38种)、花与种实昆虫群落(14种).危害程度由重到轻依次为嫩梢与针叶昆虫群落、树干韧皮部与木质部昆虫群落、花与种实昆虫群落、枝梢与嫩皮昆虫群落、灌木和草本层昆虫群落、土壤与根部昆虫群落.在青海云杉寄生或取食的昆虫多数种类为单食性或寡食性,少数种类为多食性,取食或寄生于林下灌木层和草本层的昆虫大多数为多食性,少数种类为寡食性,较少为单食性.多数种类的取食部位较为固定,但也有许多种类可以在几个部位取食. 相似文献
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经济林害虫发生现状与趋势 总被引：5，自引：0，他引：5
选择安徽省28种主栽及名特经济树种为主要对象,经过1988年至1995年8年的调查研究,探明当前各经济树种害虫种类、发生现状与趋势。在28种经济树种上查出害虫1074种,其中危害程度轻微、中等、严重的害虫分别为868种、137种和69种,分别占害虫总数的80.8%、12.8%和6.4%。经济林害虫垂直结构为食叶害虫（626种）>枝梢害虫（290种）>蛀干害虫（78种）>果实害虫（43种）>根部害虫（37种）。害虫总体发生率78.0%,其中危害轻微、中等和严重的发生率分别为41.3%、22.3%和14.4%。分析提出现阶段害虫发生类型。 相似文献
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福建省油茶林主要传粉昆虫种类及访花行为 总被引：2，自引：0，他引：2
对福建省福州、泉州、龙岩、南平、宁德等地油茶林传粉昆虫及其访花行为进行了调查,结果表明:福建省油茶林中主要传粉昆虫有24种,分属于3目11科17属,其中膜翅目的昆虫种类最多,有11种;大分舌蜂是油茶最重要的传粉昆虫,其数量多,传粉效率高;传粉昆虫日活动时间在12∶00—14∶30出现高峰,昆虫个体数量平均占全天总数的70%左右;油茶传粉昆虫的访花行为因昆虫的访花目的不同而有较大差异,温度和光照是影响传粉昆虫数量、行为和频率的主要因素。 相似文献
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Asmare Dejen Demeke 《林业研究》2020,31(1):333-337
In Ethiopia,Cupressus lusitanica and Juniperus procera are important tree species.The incidence of the cypress aphid,Cinara cupressi,which has not been reported before on the exotic Cupressus lusitanica is becoming catastrophic.The appearance of the insect was reported for the first time in 2003 in Ethiopia.However,information is scarce on the status of this species in northeast Amhara state.The objectives of this study were to assess the extent of damage,abundance and status of the cypress aphid on C.lusitanica and J.procera in the protected and cultivated forests of South Wollo,Ethiopia.Results reveal that tree compositions of the three study areas differed.The dominant tree species were C.lucitanica(15–80%),Olea europaea(5–90%)and J.procera(14–70%).The cypress aphid showed significantly higher levels of infestation on C.lusitanica(35–90%)than on J.procera(1–16%).Moreover,there was higher C.lusitanica mortality(40–93%).In contrast,there was low infestation(1–16%)on J.procera and no mortality.The results reveal that the cypress aphid causes enormous losses of C.lusitanica.Therefore,it is recommended that insect surveillance be strengthened and the introduction bioagents be considered and integrated with other insecticides to minimize the degree of C.lusitanica infestation and loss. 相似文献
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Vilma Bayramzadeh 《林业研究》2014,25(1):143-146
This work studied the effects of tree species composition on soil carbon storage in five mixed stands dominated by oriental beech and grown in the western Caspian region in Guilan province, called Astara, Asalem, Fuman, Chere and Shenrud. The thickness of the litter layer, soil characteristics, tree composition and percentage of canopy coverage were measured in each stand. Total soil organic carbon differed significantly by stand. Total （organic） carbon stores at Fuman, which had the lowest tree species richness with 2 species and least canopy coverage （75%）, were significantly （p〈0.05） higher than at other locations. Carbon stor-age in topsoil （0-10 cm） was significantly lower in Shenrud, which had the highest tree species richness with 5 species and highest canopy cov-erage （95%）. The high percentage of canopy coverage in Shenrud proba-bly limited the conversion of litter to humus. However, in the second soil layer （10-25 cm）, Asalem, with high tree species richness and canopy coverage, had the highest carbon storage. This can be explained by the different rooting patterns of different tree species. In the Hyrcanian forest. According to the results, it can be concluded that not only tree composi-tion but also canopy coverage percentage should be taken under consid-eration to manage soil carbon retention and release. 相似文献
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Pasture production in a silvopastoral system in relation with microclimate variables in the atlantic coast of Spain 总被引：1，自引：0，他引：1
F.J. Silva-Pando M.P. González-Hernández M.J. Rozados-Lorenzo 《Agroforestry Systems》2002,56(3):203-211
Grasses and legumes of high productivity and nutritional quality are a good alternative as pasture supplements in rangelands of low quality forage. Orchardgrass (Dactylis glomerata L. cv. `Artabro') and white clover (Trifolium repens L. cv. `Huia') are known as shade tolerant and low flammability species that have been successfully used in agroforestry systems in Galicia, both diminishing fire hazard compared with natural shrublands. In this study, annual and seasonal production of a grass mixture of both species was quantified during 3 years in a pinewood under different tree canopy covers. Regardless of cover, pasture production increased in summer, and decreased from fall to spring. We obtained a significant correlation between annual pasture production and light transmission through the tree canopy (R2 = 0.96, P<0.05). Light transmittance through a maritime pine canopy (Pinus pinaster Ait.) was higher than through a Scots pine canopy (P. sylvestris L.), corresponding to 36–57% and 16–21% of full sunlight respectively. The highest herbage production was obtained in no tree stands and the lowest under a P. sylvestris canopy. Fluctuations inlight transmission, temperature and PAR (Photosynthetically Active Radiation) under tree canopy were less apparent compared with no tree stands. Variation in seasonal production was more pronounced in stands without trees, and appeared more uniform when percentage of light intercepted by tree canopy increased.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
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Shuhan Wang Bingbing Zeng Mohammed Abdelmanan Hassan Shuai Qu 《Journal of Sustainable Forestry》2013,32(5):369-384
ABSTRACTLarch defoliation by Harig (Pristiphora laricis) has caused great damage in China. In this study, an attempt is made to analyze the relationships between Harig infestation and various habitat factors via the analysis of representative needles and other environmental metrics that were collected from Saihanba Mechanical Forestry Farm of Hebei Province between 2007 and 2010. The population density per tree (PD), the percentage of insect-infected trees in one sample plot (PIIT), and the infected area (IA) are treated as dependent variables when analyzing the degree of infection. The study concludes: PD and PIIT differ significantly between areas with varying species composition; canopy density and stand density negatively correlate with PD; Harig appears not to infect young growth; and infections have the tendency to spread to high altitudes. In order to provide a basis for macro prevention and control of insect attack, the habitat factors most closely related to the occurrence of insect attack are inputted into an information load GIS model to estimate the potential damage from infection. 相似文献
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In a long-term study (1980 to 1993), the survival, growth performance and biomass production of two grass species viz. Chrysopogon
fulvus (Spreng.) Chiov. and Eulaliopsis binata (Retz.) C.E. Hubb. were assessed when intercropped with four tree species viz.
Albizia lebbek (L.) Benth., Grewia optiva Drumm., Bauhinia purpurea L. and Leucaena leucocephala (Lamk.) de Wit. on the bouldery
riverbed lands of Doon Valley of north-west India. The survival of grass clumps was higher under the canopy of B. purpurea
(48.3% in 1993 of the initial planting density of 20,000 clumps ha−1 in 1980) and G. optiva (47.4%) than of L. leucocephala (31.1%) and A. lebbek (29.4%), and at 75% intensity of tree lopping
(40.9%) than at 50% (37.1%). The effect of tree species on different growth parameters of grasses was not uniform, with G.
optiva and B. purpurea causing comparatively more synergistic effect on clump height and clump diameter respectively. Although
the performance of grasses was good under A. lebbek and L. leucocephala in the early years (1980--1987), these tree species
resulted in the lowest grass dry weight in the later years up to 1993. The beneficial effect of higher lopping intensity of
75% was observed on the growth and biomass production of grasses over 50% lopping, presumably due to increased light penetration
into the under-storey. The biomass production of grasses reached a maximum at four years of growth in 1983, after which, it
decreased gradually to less than half in 1993. Eulaliopsis binata showed higher survival, growth and biomass production than
C. fulvus throughout the period of study. The total biomass production was highest in association with B. purpurea followed
by G. optiva, which appeared to be the most suitable tree species along with E. binata for sustainable silvopasture development
on the marginal lands of Doon Valley of north-west India.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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Light is the most common limiting factor in forest plant communities,influencing species composition,stand structure,and stand productivity in closed canopy stands.Stand vertical light structure is relatively simple under a closed canopy because most light is captured by overstory trees.However,wind disturbance events create canopy openings from local to landscape scales that increase understory light intensity and vertical light structural complexity.We studied the effects of an EF-1 tornado on horizontal and vertical(i.e.three-dimensional)light structure within a Quercus stand to determine how light structure changed with increasing disturbance severity.We used a two-tiered method to collect photosynthetic photon flux density at 4.67 m and 1.37 m above the forest floor to construct three-dimensional light structure across a canopy disturbance severity gradient to see if light intensity varied with increasing tornado damage.Results indicate that increased canopy disturbance closer to the tornado track increased light penetration and light structure heterogeneity at lower forest strata.Increased light intensity correlated with increased sapling density that was more randomly distributed across the plot and had shifted light capture higher in the stand structure.Light penetration through the overstory was most strongly correlated with decreased stem density in the two most important tree species(based on relative dominance and relative density)in the stand,Quercus alba L.(r=-0.31)and Ostrya virginiana(Mill.)K.Koch(r=-0.27,p<.01),and indicated that understory light penetration was most affected by these two species.As managers are increasingly interested in patterning silvicultural entries on natural disturbances,they must understand residual stand and light structures that occur after natural disturbance events.By providing spatial light data that quantifies light structure post-disturbance,managers can use these results to improve planning required for long-term management.The study also provides comparisons with anthropogenic disturbances to the midstory that may offer useful comparisons to natural analogs for future silvicultural consideration. 相似文献