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华南地区桉属树种种源生长表现 总被引：6，自引：0，他引：6
在华南地区，桉属树种的多点试验结果表明，细叶桉和赤桉的优良种源在各种不同的立地条件下，其近期保存率和立木蓄积量都比当地原主栽树种窿缘桉高１倍以上；在较好的立地条件下，尾叶桉产量最高，该树种最优种源２年生立木蓄积量比最差种源大１３９．２％，细叶桉５年生立木蓄积量最好种源比最差种源大２１．１１倍，赤桉５年生立木蓄积量最好种源比最差种源大６６％。 相似文献
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本文概述刚果12号桉无性系和实生苗在相同立地条件下的生长情况。经过四年的观察调查研究，基本掌握了刚果12号桉的生长规律，种植4年桉树的林分，无性系桉每公顷立木蓄积46.5m^3秆，平均年公顷立木蓄积量：无性系为16.1m^3，实生苗桉为11.6m^3，无性系桉和实生苗桉的保存率分别为94％和87％。 相似文献
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本文对邵武市卫闽林场的16和18指数立地上，不同密度15年生杉木立木蓄积量和可生产的不同规格杉木原条出材量，进行经济核算，结果表明；16指数立木造林密度1410株／hm~2的立木蓄积量比同指数630株／hm~2密度增产69．0％；比18指数密度630株／hm~2的林分增产36．3％。该林分的综合经济效益占第二位。 相似文献
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该项研究采用吉林长白山林区1：2600比例尺黑白航片，进行主要测树因子量测试验。为解决航片量测与实验结果的可比性，该试验在样地野外每木检尺的同时，划定树木生长级并排序。以航片量测株数为准，取等量实测立木对比（从上层顺取） 这样，不仅对比株数相等，对比用的单株也大体在同一范围，并在查明样地被压木数量与航片漏测立木的比率后，根据航片立木漏测规律，编制漏测木蓄积量补偿表，以提高森林蓄积量估测精度。本试验测高业均方误±1．07m，蓄积量估测精度均方误±6．0m^8。展示了用大比例尺航片量测的实用前景。 相似文献
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我国绿洲防护林冬季相防风效应的估算 总被引：2，自引：0，他引：2
以林网区贴地层相对风速为目标函数,以动力平衡为基础,利用立木蓄积量指数(单位面积农田所拥有的立木蓄积量)与林网冬季相防风效应的近似对应关系,估算我国北方农田林网化对冬春季地面风力的影响。结果表明：我国北方绿洲防护林立木蓄积量整体不足,冬春季防风效应较差,局部可观测到很好的防风效应但不具有普遍性;立木蓄积量指数较小时增量效益较好,立木蓄积量指数越大增量效益越小,裸耕地和蓄积量很少的地区存在较大的防风效应增益区间;修枝对防风效应的影响在立木蓄积量指数较小的区域明显,立木蓄积量指数较大的区域不必牺牲木材经济价值而保留很多侧枝;对于立木蓄积量指数已经很大的地区,没有必--求生长量大于采伐量、蓄积量持续增长。 相似文献
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以营造在福建邵武6年生南酸枣与杉木不同模式混交林及其纯林和5年生南酸枣密度试验林为研究对象,对南酸枣人工林早期生长规律、不同立地条件下人工林生长差异、不同造林密度对南酸枣早期生长的影响、以及与杉木混交后不同模式林分的生产力、生物量差异和对林地土壤肥力的影响进行了研究。结果表明:南酸枣早期生长快,在中等肥力立地上,6年生平均高为8 53m,平均胸径9 74cm,立木蓄积量86 08m3·hm-2,在不同立地条件下生长差异明显;造林密度对南酸枣早期生长的影响表现出密度越大立木蓄积量和枝下高越大,冠幅越小的趋势。与杉木混交后能促进杉木的生长和有利于维护地力,其中以杉3∶南1(3∶1)混交模式生产力和生物量较高,蓄积量为76 42m3·hm-2,生物量为41 5127t·hm-2,与杉木纯林相比,分别提高了74 55%和97 27%,是值得推广的杉阔混交模式。 相似文献
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WANG Baoping LI Jiyue SUN Zhiqiang WEN Ruijun QIAO JieZHOU Haijiang LI Zongran. Paulownia Research Development Center Zhengzhou P.R. China.College of Resources Environment Beijing Forestry University Beijing P. R. China 《中国林业科技(英文版)》2004,3(1):80-86
TreesgrowthregularityandtheirannualgrowthrhythmareusuallysimulatedandanalyzedbyRichardsequation(TangShouzheng,etal,1999;RichardsJ,1959;WangMingliang,etal,2000).However,previousstudiesonPaulowniaannualgrowthrhythmhavebeenlaidparticularstressonseedlingscultureandyoungplantletselectionofclonesbutlackofrelevantstudyonwoodcycles(ZhaoDaning,etal,1993;FuDali,etal,2001;ZhouYongxue,etal,1996).ThenaturaltrunkextensionanditsstraightnessofPaulowniaarerestrictedprodigiouslybycharacteristicsofpseudo-d… 相似文献
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Non-destructive methods for determining the biomass and leaf area of individual trees throughout their growing cycle are an
essential tool in agroforestry research, but must be capable of providing reliable estimates despite the influence that management
strategies such as pruning may have on tree form. In the present study, allometric methods involving measurements of the diameter
of all branches provided reliable estimates of canopy leaf area and biomass for grevillea trees (Grevillea robusta A. Cunn.; Proteaceae) grown as poles, but proved unsuitable for routine measurements because of their time-consuming nature.
An alternative, less laborious method based on measurements of trunk cross-sectional area immediately below the first branch
of the canopy provided satisfactory allometric estimates of leaf area and canopy biomass. Trunk biomass was determined from
measurements of tree height and diameter at breast height using established methodology based on the assumption that trunk
volume may be calculated using a quadratic paraboloid model; biomass was determined as the product of trunk volume and the
specific gravity of the wood. The theoretical basis, development and validation of allometric methods for estimating tree
growth are discussed and their wider applicability to other agroforestry systems is assessed.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
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研究以广东省郁南林场大东坑工区内 51 年生灰木莲 Manglietia conifera 为研究对象，对灰木莲树高、胸径、材积、树干通直度、侧枝生长习性等指标进行调查和分析。结果表明：51 年生灰木莲生长良好，胸径平均为 44.28 cm，最大为 79.60 cm，树高平均为 20.79 m，最高为 27.00 m，单株材积平均为 1.48 m3，最高为 3.65 m3。可见，灰木莲引种在广东郁南适应性强，能够生长良好，具有生长速度快，树干通直，自然整枝好等特点，是该地区可以推广种植和培育大径材的优良树种。 相似文献
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通过对黑龙江省东部山地不同蓄积量的典型天然次生林的枯落物层、土壤层持水性能进行的研究,结果表明:随着单位面积蓄积量的不断增加,枯落物层、土壤层的有效持水量、最大持水量均有着不同程度的提高。其中单位面积蓄积量对枯落物层有效持水量的影响稍弱,但整体基本保持蓄积量增加、有效持水量也增加的趋势。通过指数回归分析可以看出,在林分静态持水各项能力指标中,单位面积蓄积量分别对枯落物层最大持水量、土壤层有效持水量影响最为显著。当蓄积量为241.56-369.95 m3.hm-2时,林分静态持水能力趋于稳定,水源涵养功能达到最大。 相似文献
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通过2012—2013年顺昌县大历镇阔叶树保留木资源调查分析,结果表明:不同径阶阔叶树保留木的株数分布整体上呈"L"形,每个径阶阔叶树保留木达200株以上的主要分布于径阶为6~14cm之间,共有1 499株,占总数的73.37%;径阶16cm以上保留的株数仅占总数的26.63%。阔叶树保留木中间层中径木,共有1 978株,占总数的96.82%;上层大树仅65株,仅占总数的3.18%。不同径阶的阔叶树保留木蓄积量分布基本上呈正态分布,径阶5~14cm阔叶树保留木蓄积量为63.82m~3,占总保留木阔叶树蓄积量187.29m~3的34.08%;径阶16cm以上的阔叶树保留木蓄积量为123.47m~3,占总保留木阔叶树蓄积量的65.92%,是径阶5~14cm阔叶树保留木蓄积量1.93倍。阔叶树中间层中径木蓄积量为146.08m~3,占总蓄积量的78%;上层大树蓄积量为41.21m~3,蓄积量占总数的22%。阔叶树保留木胸径5~14.9cm共需补偿3 191元,胸径15cm以上需补偿12 347.00元,大历镇阔叶树保留木共需补偿15 538.00元。阔叶树保留株数平均值为138.6株?hm~(-2),阔叶树蓄积量保留平均值为12.75m~3?hm~(-2),阔叶树保留木不炼山造林成本从造林至郁闭前需投资27 000元?hm~(-2)。 相似文献
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Tree growth and management in Ugandan agroforestry systems: effects of root pruning on tree growth and crop yield 总被引：1，自引：0，他引：1
Tree root pruning is a potential tool for managing belowground competition when trees and crops are grown together in agroforestry systems. We investigated the effects of tree root pruning on shoot growth and root distribution of Alnus acuminata (H.B. & K.), Casuarina equisetifolia L., Grevillea robusta A. Cunn. ex R. Br., Maesopsis eminii Engl. and Markhamia lutea (Benth.) K. Schum. and on yield of adjacent crops in sub-humid Uganda. The trees were 3 years old at the commencement of the study, and most species were competing strongly with crops. Tree roots were pruned 41 months after planting by cutting and back-filling a trench to a depth of 0.3 m, at a distance of 0.3 m from the trees, on one side of the tree row. The trench was reopened and roots recut at 50 and 62 months after planting. We assessed the effects on tree growth and root distribution over a 3 year period, and crop yield after the third root pruning at 62 months. Overall, root pruning had only a slight effect on aboveground tree growth: height growth was unaffected and diameter growth was reduced by only 4%. A substantial amount of root regrowth was observed by 11 months after pruning. Tree species varied in the number and distribution of roots, and C. equisetifolia and M. lutea had considerably more roots per unit of trunk volume than the other species, especially in the surface soil layers. Casuarina equisetifolia and M. eminii were the tree species most competitive with crops and G. robusta and M. lutea the least competitive. Crop yield data provided strong evidence of the redistribution of root activity following root pruning, with competition increasing on the unpruned side of tree rows. Thus, one-sided root pruning will be useful in only a few circumstances. 相似文献
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Majid AZIZI Mohammad Mehdi FAEZIPOUR Ali BAYATKASHKOOLI Fatemeh TAHERI 《中国林学(英文版)》2013,15(4):363-369
Fast growing poplar species enjoy a highly favored position in Iran＇s forest product industries. Howeve~ information on poplar plantations, such as areas, growing stock and harvest volumes, are largely obtained by now scientific means and poorly executed methods. A few studies have been conducted to obtain data on the capacit,. of poplar plantations, their extent, existing growing stock, distribution and species choice in three provinces, i.e. Western Azerbaijan, Kurdistan and Hamedan, with relatively well developed management systems. We opted for cluster method, a standard sampling method for conducting similar investigations, consisting of two phases. In the firs phase we collected library information and conducted half-open interviews with villagers. In the second phase fiel~ measurements in the villages of these three provinces were carried out. Information from field measurements on growin! stock, cultivated areas, dominant species were used to estimate volumes by way of volume and weight tables. Result~ obtained from the present study indicate that the average annual volume of timber harvested in the three province~ was 697,723 m~, with an average sampling error of 22.7 per cent. This annual volume of poplar timber harvested fron the three provinces was estimated to amount to about 25 per cent of overall harvest; at that rate, the overall annu~ utilization potential of poplar plantations will be 10 million m3, which constitutes a reliable resource of raw timber for us~ in wood and paper industries. 相似文献