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人工林地力衰退研究进展 总被引：17，自引：0，他引：17
论述国内外人工林地力衰退的现状,世界各地许多人工林都存在不同程度的地力衰退问题,出现衰退的造林树种主要有欧洲云杉、海岸松辆射松、日本落叶松、油棕、柚木、桉树、欧洲松等;在我国杉木、桉树、马尾松、杨树、长白落叶松、华山松等树种出现了生产力衰退现象。人工林地力衰退与气候、土壤、树种、人工林群落结构、育林措施等诸多因素有关。防治人工林方式,建立生态林业;改善人工林的经营制度;使用组装配套技术,提高经营水平。 相似文献
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利用田间试验方法，对山东省莒县沭河流域杨树多代经营人工林产区不同林地间作农作物、林地抽沙换土、杨树人工林品种间轮作等措施对杨树人工林多代连作地力维持效果进行研究。结果表明：抽沙换土有利于胸径和树高生长，土壤有机质、速效氮、速效磷、速效钾和微量元素Cu、Zn、Mn的含量增加，土壤脲酶、过氧化物酶、多酚氧化酶活性和土壤微生物总量增加，其中真菌、细菌、放线菌分别增长了1．55倍、2．05倍和1．24倍；主伐更新更换不同品种以后，土壤有机质、土壤速效氮和速效钾含量3年保持增长，土壤脲酶、过氧化物酶、多酚氧化酶活性增加，土壤微生物总量提高，其中真菌、细菌、放线菌分别增长了3．18～23．91倍、3．40～28．71倍和0．71～2．80倍；林地间作有利于提高土壤有机质、速效磷、速效钾和微量元素Fe、Mn含量，土壤酶活性和土壤微生物数量增加，其中真菌、细菌、放线菌分别增长了1．38～3．39倍、1．28～7．73倍和0．79～3．11倍。间作林地的胸径和树高较对照分别提高了15．25％～37．84％和8．17％～29．12％。 相似文献
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笔者通过对比桉纯林与桉、大叶相思混交育林对地力、林木生长量、生物存量的影响,进行了桉与固氮树混交的试验对比研究,结果表明:桉与大叶相思混交造林,对林分土壤表层的养分具有一定的补给作用,也加速了速效钾的生成,但对林分土壤中速效磷的影响不明显.在有机物含量上,如果林分凋落物能够保留,则土壤中的有机物会保持一定量的增长,保证... 相似文献
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人工林地力衰退现象时有报道,引起了国内外普遍关注。地力衰退已成为培育人工林过程中的一个技术障碍。人工林地力衰退机理和防止对策的研究是当前和将来营林科学的研究热点。 相似文献
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浅论落叶松人工林地力衰退的原因与对策 总被引：4，自引：0，他引：4
浅论落叶松人工林地力衰退的原因与对策苑辉，付宝东，张东江（辽宁省林科院沈阳１１００３２）（开原市林业局）落叶松是我国北方重要的用材树种，近几十年来，营造了大面积的落叶松纯林，由于只注重林木的速生丰产，忽视了林地生产力的维护，因而在林业生产中，致使落叶... 相似文献
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J. D. M. Keet 《Southern Forests》2013,75(1):3-9
The basic principles in protection of forests from fire are concerned with: a. precaution b. care and diligence c. negligence and contributory negligence all of which are closely inter-related and determine a person's conduct in particular circumstances, antecedent, during and subsequent to the event. Statutory enactments regulate our actions in all these matters. The direct and indirect benefits of forests are indispensable to life and therefore truly national; it consequently concerns the State, or the people, that the asset in our forests or plantations should be adequately protected. This being so, and to this end, the Government has stepped in to assist us by means of provisions in soil conservation schemes for clearing of firebelts on common boundaries of properties, and also by the establishment of fire protection areas administered by fire protection committees, who can obtain financial assistance by way of grants out of public funds. 相似文献
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Degraded Aravalli hills in western India require rehabilitation through resource conservation and afforestation for meeting the biomass needs of resource-poor tribes of the region. Rainwater harvesting treatments i.e., control, Contour trench (CT), Gradonie (G), Box trench (BT) and V-ditch (VD) were prepared in <10%, 10–20% and >20% slopes categories and Dendrocalamus strictus L. seedlings were planted in August 2005 with a view to conserve soil and water and increase the productivity of the hills. Soil water content (SWC), survival and height of D. strictus plants were highest (P < 0.05) in <10% slope and all these variables decreased with increase in slope. SWC increased by 27.45% and 25.68% in <10% and >20% slopes, respectively than in 10–20% slope. From lowest in control SWC increased by 11.95%, 20.21%, 17.61% and 11.49% in CT, G, BT and VD treatments, respectively. Growth variables were highest in VD plots but the increase in shoot number was highest (2.9-fold) in CT plots. Increase in effects of rainwater harvesting with time indicated by a change in production pattern from highest (P < 0.05) fresh and dry herbage in <10% slope in 2005 to 10–20% slope (24.66% and 26.09%) in 2006 and >20% slope (42.42% and 48.35%, respectively) in 2007. The increase in herbage was 1.17–2.40-fold in fresh and 1.20–2.52-fold in dry herbage over control. Highest (P < 0.01) production was in V-ditch plots. The treatments order for herbage production was C < CT < G < BT < VD. But the production was highest in BT in <10% and in V-ditch plots in 10–20 and >20% slopes. Conclusively, soil water status is affected by natural slope, stony soil surface and rainwater harvesting structures influencing seedling growth and herbage production. Box trench and V-ditch enhanced surface soil water facilitating herbage growth, whereas contour trench facilitated deep soil water storage, which was made available to the plants after monsoon. Thus rainwater harvesting practices enhanced vegetation cover and productivity of the degraded hills and can be replicated to conserve soil resource and increase biomass for rural poor of the region. 相似文献
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桉树立地生产力与养分生产力参数的确定 总被引：9，自引：0，他引：9
桉树试验林样本分析结果表明，桉树树杆中氮，磷，钾养分浓度的倒数与养分吸收量早明显的负线性相关。基于这一相关性，对实测的数据作回归分析。估测的立地生产力极限和养分生产力参数值，以及相应的立地养分效应曲线具有较高的精确度。本文为研究林木生长和营养的动态函数关系提供了新的思路和方法。 相似文献
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Using historical growth series data of Scots pine (Pinus sylvestris L.) in Central Europe we examine all the dynamic site equations previously used for modeling the height growth of this species as well as a new dynamic site equation that has not been used previously in the context of this forestry data. The tested models included two groups of anamorphic and polymorphic dynamic site equations (three-dimensional site–height–age models, such as Y = f(t,t0,y0)). One group of the models is based on the algebraic difference approach (ADA) implementation of different, preexisting base equations (two-dimensional equations, such as Y = f(t)). The other group of models is based on newer generalized algebraic difference approach (GADA) formulations of new site–height–age relationships that may use older models only as a part of their structure. The models were selected because they were relevant to Scots pine height growth modeling in other studies. We compared all the models with each other in terms of the sum of square deviations associated with fitting them simultaneously to all sites represented by the Scots pine data. All the fits were based on base-age invariant stochastic regressions, in which the global model parameters that are common to all growth series are estimated simultaneously with the site-specific effects that are different for each of the site productivity series. Cieszewski's model [Cieszewski, C.J., 2005. A new flexible GADA based dynamic site equation with polymorphism and variable asymptotes. PMRC Technical Report 2005-2] best described the data. 相似文献
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对我国森林立地分类与评价问题的几点看法 总被引：8，自引：0，他引：8
本文首先回顾了国内一些学者近期有关森林立地分类和评价方面学术争论的要点,然后提出我国立地分类和评价应遵循的原则和方法,并着重论述在一个局部地区应如何抓住地形和土壤这两大因素在立地类型划分和评价中的重要性。 相似文献
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森林立地分类原理的探讨 总被引：4，自引：0，他引：4
立地分类与立地区划为两个并列的系统,二者不能混淆。除提出了一般原则外,还确定了立地分类的四大依据:1.立地基底;2.立地形态结构;3.生物气候肥力;4.立地表层特征。立地分类系统、立地系列、立地纲、立地目、立地类型组、立地类型(亚型)。规定了立地目-立地类型组-立地类型(亚型)的三名法命名法则,并列举了幕阜山立地分类的范例。 相似文献
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Tomohiro Nishizono Kunihiro Tanaka Kazuo Hosoda Yoshio Awaya Yasuhiko Oishi 《Journal of Forest Research》2008,13(5):264-274
We analyzed data from 28 long-term experimental monitoring plots installed in Japanese cedar (Cryptomeria japonica D. Don) plantations in northeastern Japan to examine how site productivity and thinning practices relate to culmination in
stand growth. Site productivity and thinning practices in the plots were evaluated by site index (dominant tree height at
40-years old) and by cumulative thinning rate (cumulative thinning volume divided by cumulative gross production during the
entire period of measurement). Culmination of stand growth was evaluated by culmination age of the mean annual increment (MAI)
and its maximum value (Max MAI). Max MAI for the mean annual gross increment (MAIgross) and mean annual net increment (MAInet)
increased with increasing site index, but did not change with cumulative thinning rate. Culmination age for MAIgross decreased
with increasing site index, but did not change with cumulative thinning rate. Culmination age for MAInet decreased with increasing
site index. Additionally, culmination age for MAInet increased with increasing cumulative thinning rate in sites with a high
site index (>19.3 m) but not in those with a low site index (<19.3 m). These results indicate that thinning extends the culmination
age without changing Max MAInet under high site productivity. Therefore, thinning increases total net yield in sites with
high productivity based on a long-term perspective. 相似文献
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试论建立我国森林立地分类系统 总被引：5，自引：0，他引：5
森林立地分类、评价及其应用,是造林营林工作的科学基础。建立全国森林立地分类系统就包含了“立地区划”的任务,森林立地分类单位就是立地区划单位。本文阐述了立地分类的原则和分类系统单位,并提出了我国包含3个立地区域、17个立地带、58个立地区和163个立地亚区的森林立地分类系统方案。 相似文献
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Carbon (C) accreditation of forest development projects is one approach for sequestering atmospheric CO2, under the provisions of the Kyoto protocol. The C sequestration potential of reforested mined land is not well known. The purpose of this work was to estimate and compare the ecosystem C content in forests established on surface, coal-mined and non-mined land. We used existing tree, litter, and soil C data for fourteen mined and eight adjacent, non-mined forests in the Midwestern and Appalachian coalfields to determine the C sequestration potential of mined land reclaimed prior to the passage of the Surface Mining Control and Reclamation Act (1977). We developed statistically significant and biologically reasonable models for ecosystem C across the spectrum of site quality and stand age. On average, the highest amount of ecosystem C on mined land was sequestered in pine stands (148 Mg ha−1), followed by hardwood (130 Mg ha−1) and mixed stands (118 Mg ha−1). Non-mined hardwood stands sequestered 210 Mg C ha−1, which was about 62% higher than the average of all mined stands. Our mined land response surface models of C sequestration as a function of site quality and age explained 59, 39, and 36% of the variation of ecosystem C in mixed, pine, and hardwood stands, respectively. In pine and mixed stands, ecosystem C increased exponentially with the increase of site quality, but decreased with age. In mined hardwood stands, ecosystem C increased asymptotically with age, but it was not affected by site quality. At rotation age (60 yr), ecosystem C in mined hardwood stands was less on high quality sites, but similar for low quality sites compared to non-mined hardwood stands. The overall results indicated that the higher the original forest site quality, the less likely C sequestration potential was restored, and the greater the disparity between pre- and post-mining C sequestration stocks. 相似文献