共查询到20条相似文献，搜索用时 140 毫秒
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人工林,包括农田防护林在内的人工栽植的林木,通过施肥达到速生增产的目的,国内外已有许多文献报道,在理论和实践上均取得了科学的、满意的效果。结果表明:施肥与林木生长呈正相关。 这里着重讲施肥与林木速生的重要关系。 林木的生长和发育,需要多种营养元素。这些元素多以离子状态被树木根系和叶面吸收,并通过输导组织输运到树体各部位,参与生长和代谢过程的各种生理生化活动,促进林木的正常生长发育。 相似文献
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林木生长函数是林木生长规律的定量描述。利用非线性回归法,详细论述了确定林木生长非线性函数的方法,结合计算机程序和实测数据,建立了某红松林木生长函数的数学模型。分析计算结果表明,林木生长数学模型与实测数据有较高拟合精度,相对误差平均值约1.8%。 相似文献
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云南红豆杉人工林幼树期林木的高径生长节律及其与气象因子的关联分析 总被引：5，自引：2，他引：3
以种植于云南省林业科学院昆明树木园的云南红豆杉人工林幼树期的林木为研究对象,通过对其林木2007～2008年连续2年各月的树高、地径的生长观测,并结合相应时期的气象因子,采用有序样本的聚类分析方法对林木在1年内的生长阶段进行了划分,进而采用逐步多元回归和通径分析方法,分析年内各月的不同气象因子与其林木年内各月的树高、地径生长量的相关关系.结果表明:云南红豆杉人工林幼树期林木在1年内的生长可划分为生长初期、生长盛期和生长后期3个阶段;4～9月为生长盛期,其林木的树高和地径的生长量分别占全年总生长量的79.89 %和64.35 %;而表层(土层20 cm)土壤的月均温度是影响林木生长量的主要气象因子. 相似文献
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研究了马尾松木材比重在林分间和林分内单株间的变异规律,探讨了马尾松木材比重与林木生长、形态性状间的相关关系。结果表明,马尾松木材比重在林分间、林分内都存在显著性差异,木材比重只与林木生长、形态性状中的树皮厚度存在显著相关性。 相似文献
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通径分析最早是由S.wright(1921)提出的,应用于遗传育种的研究上,用以阐明相关变量间的因果关系。由于利用通径系数进行的通径分析,具有直观、精确等优点,因此近十几年来应用日趋广泛。在土壤科学领域里,在研究土壤性状与林木生长的关系中,除了林地所处的海拔高度、坡向、坡位、坡度等影响着林木生长外,可以看到土壤各性状因子如腐殖质层厚度、土壤养分状况、土壤质地、结构、有效土层厚度、障碍层次出现的部位和厚度等等,都和林木的生长密切相关,而且土壤各性状因子之间也有一定程度相关。在平原地区,土壤性状因子与林木生长的这种相关,更为 相似文献
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阐明了林木生长相关的概念及普遍性、多样性、规律性、关键性。对国内外景新研究成果１００例进行应用价值评介。 相似文献
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The diameter growth of trees may vary depending on the tree size, species and other tree-related factors. However, such variation is challenging to consider while estimating the growth response to weather conditions. This study investigated the effects of the weather conditions and variations in tree factors on diameter growth in a mature forest. In particular, we focused on diameter growth in June, the month of active diameter growth. We recorded the monthly diameter growth of 6 tree species for 7 years and constructed a generalized linear mixed model in which the mean growth was dependant on tree size, weather conditions, and the interaction between tree size and weather. 相似文献
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《林业研究》2021,32(1)
The Atlantic Forest is one of the largest and most biodiverse rainforests of South America but anthropogenic activities are drastically changing these landscapes.The invasion of alien or exotic species is one of the greatest threats to biodiversity.There are few studies of invasive species in tropical Brazilian ecosystems.This research examines growth and ecological aspects of Syzygium cumini and Clitoria fairchildiana,two invasive tree species in the Pedra Branca State Park,an Atlantic Forest remnant in southeastern Brazil.Both species were successfully dated,indicating an average age of 58 and 31 years,respectively.A positive relationship between growth and precipitation of the previous growing season suggests an ecological adaptive strategy,which could be facilitating their invasion into the environment.Cumulative growth diameter curves indicate slow and fast growth rates for S.cumini and C.fairchildiana,respectively.Growth release episodes detected in the tree rings indicate increased anthropogenic disturbances over the last 50 years. 相似文献
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Tree growth, survival and crop yield under agrisilvicultural practices were analyzed over a seven-year period in a split plot
experiment on acid alfisol under rainfed conditions at ICAR Research Farm, Barapani (Meghalya), India. Three indigenous species
including a fruit plant, and one introduced tree species formed the main plot treatments and three crop sequences were the
sub-plot. The tree species were mandarin (Citrus reticulata), alder (Alnus nepalensis), cherry (Prunus cerasoides) and albizia
(Paraserianthes falcataria), and the crop sequences were (a) soybean (Glycine max)-linseed (Linum usitatissimum) for three
years, then groundnut (Arachis hypogea)-mustard (Brassica campestris) for three years followed by soybean-linseed in the seventh
year, (b) groundnut-mustard for three years, then soybean-linseed for three years and groundnut-mustard in the seventh year,
and (c) sole trees (‘tree only‘). A positive effect of intercropping on height and diameter growth, crown width and timber
volume was observed in alder, albizia and cherry but no appreciable differences for these parameters were observed in mandarin
between the two situations. Alder and albizia attained maximum growth and woody biomass followed by cherry and the minimum
growth was recorded by mandarin. The better growth and timber volume in the ‘tree+crop’ situation was mainly due to the application
of fertilizers and weeding. Crop yield reduction was observed with alder, mandarin and cherry and as the distance from tree
increased, yield also improved. However, in albizia the proximity of tree did not reduce crop yield. The implications of the
results are discussed in the context of the suitability of the species in this region and their usefulness in agroforestry
systems.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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广东古兜山次生林引入更新树种选择研究 总被引：1，自引：1，他引：0
为探索低质低效次生林经营改造技术,以广东省古兜山南亚热带次生林为研究对象,通过树种引入套种更新试验,进行优良树种的选择评估。研究以生长适应性、经济效益、生态功能和景观功能为树种选择的主要依据,确定了13项定性和定量分级指标,采用4分制建立各项指标的分级标准,运用层次分析法,构建了南亚热带次生林引入套种树种的评价指标体系,对试验林中7．5 a生的引入套种树种的综合表现进行分析与评价。结果表明,69个引入套种树种的综合评价值分布在1．74-3．08之间,树种间综合表现差异明显,壳斗科、樟科、金缕梅科等本地植物区系优势科的树种表现较好。在树种综合表现值的基础上,根据树高、胸径的年均生长量将套种树种分为速生型、中等速生型和慢生型3个类型,评选出综合表现值在2．5以上的优良树种37个,其中速生型树种7个、中等速生型树种17个、慢生型树种13个,为南亚热带次生林引入套种以及人工促进更新树种的合理选配提供参考。 相似文献
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This study explores the diversity in sensitivity to drought of moist tropical forest tree species. Yearly tree growth records collected over a ten-year period in two one-hectare 70-year-old damar agroforest plots in Sumatra are analysed. These agroforests are mixed tree plantations, dominated by Shorea javanica K. & V., a dipterocarp tree cultivated and tapped for its commercially valuable resin (damar). Many indigenous fruit tree species grow in these agroforests, as well as timber tree species originating from the nearby natural forest. During the census period the multi-species stands were subjected to three El Nino Southern Oscillation (ENSO)-related droughts (1994, 1997 and 2002). At the tree community level, these droughts were associated with a marked decrease in radial stem growth. Multilevel modelling was used to explore the relative contribution of species, tree size and individual tree characteristics to the observed response to drought.All tree species appeared to be sensitive to drought but the amplitude of the response varied significantly across species. Predicted species mean decrease in stem radial growth rate on drought years (i.e. years with 6 months with less than 50 mm/month rainfall) ranged from less than 5% to more than 80%. Shared species were ranked consistently between plots indicating that the results were robust. Stem diameter significantly affected tree sensitivity to drought in two species only, but in opposite ways: in S. javanica, larger trees appeared to be less sensitive while the opposite was true for Lansium domesticum, an abundant fruit tree. Individual tree sensitivity to drought contributed significantly albeit to a small extent to the overall response to drought. This individual tree effect did not show any pattern of spatial correlation and hence could not be related to topographic features. It is likely to reflect the individual's unique history and genotype. 相似文献
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Jochen Schöngart Florian Wittmann Martin Worbes Maria Teresa Fernandez Piedade Hans-Jürgen Krambeck Wolfgang Johannes Junk 《Annals of Forest Science》2007,64(6):657-664
Ficus insipida Willd. (Moraceae) is a fast growing tree species of early successional stages in the Amazonian nutrient-rich white-water floodplains (várzea). The species is one of the most economically important low-density wood species in the community-based forest management project in the Mamirauá Sustainable Development Reserve (MSDR) in Central Amazonia, where timber species are managed using a polycyclic selection system with a minimum logging diameter (MLD) of 50 cm and a cutting cycle of 25 years. In this study we analyze the floristic composition, stand structure and forest regeneration of a natural 20 year-old stand at an early successional stage and we model tree growth of diameter, height and volume of F. inspida based on tree-ring analysis to define management criteria. The volume growth model indicates that the preferred period for logging should be at a tree age of 17 years when the current annual volume increment peaks. This age corresponds to a diameter of 55 cm, which would be an appropriate MLD. 相似文献
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Growing concern for economic and environmental issues emphasizes the potential value of intercropping systems in temperate
regions. However, the selection of relevant tree species to be associated with crops has been little documented. The growth
and the nitrogen nutrition of two economically valuable species, wild cherry (Prunus avium L.) and hybrid walnut (Juglans nigra L.×Juglans regia L.), were compared over six years after plantation. These two species were associated with non-irrigated cereal crops in
the agroforestry treatment or grown separately (weeded control and fallow). Intercropping increased diameter growth as soon
as year 2 in the two species. Leaf biomass assessment using allometric models showed an earlier and greater leaf biomass increase
in hybrid walnut than in wild cherry tree. After six years, the relative growth increase of the agroforestry trees with respect
to the control trees varied with the parameter considered (diameter at breast height from +26 to +65%, leaf biomass from +54
to +142%) and with the tree species (higher relative growth for hybrid walnut trees). The beneficial effect on tree growth
can be accounted for in terms of enhanced nitrogen nutrition. The tree–crop association in intercropping systems, which improves
tree growth, might thus allow the planting of more demanding trees on soils of lower fertility. 相似文献