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以广西冷寒区的几个桉树树种的人工林为研究对象,对比分析不同树种的桉木旋切单板外观质量特性以及林分密度对其影响。结果表明：在树种的单板外观质量如针节、活节、死节、孔洞、端裂等方面,各树种之间均差异显著;同样林分密度对其影响也很显著,高林分密度有利于单板外观质量改善;单板外观质量性状聚类分析结果表明：邓恩桉、本沁桉、柳桉、尾巨桉单板材性相近,而粗皮桉和巨桉显著地区别于其他树种;依据外观质量综合评价结果,适合于冷寒区发展的桉树胶合板材培育的有柳桉、邓恩桉、大花序桉、本沁桉树种,以柳桉为最优选择。 相似文献
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邓恩桉(Eucalyptus dunnii)是优良的耐寒桉树树种,其大径材培育具有广泛的应用前景。本研究对2009年营建的9年生邓恩桉林分进行保存率、胸径、树高和形质调查分析,为邓恩桉大径材培育提供理论基础。结果表明:处于不同坡位的林分保存率、胸径、树高和形质存在差异。上坡的保存率最高(60%)。不同坡位间的树高生长存在极显著差异、单株材积存在显著差异,其中下坡的生长量最高,平均树高为22.9 m、平均胸径17.8 cm、平均单株材积为0.29m~3、单位面积蓄积量为15.09 m~3。下坡的林木干形最优,63.46%的林木没有明显弯曲;上坡的林木干形最差。邓恩桉实生苗林分生长分化大,在培育过程中应根据各坡位的情况采取相应强度的间伐措施。 相似文献
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本文对15种桉树在广西桂北区引种适应性进行了比较。苗期研究结果表明：粉绿桉、白皮桉、史密斯桉、毛皮桉、溪谷桉、高桉、辐射桉7种桉树在苗期出芽率、成苗质量上表现较差。对邓恩桉、柳桉、本沁桉、巨桉、赤桉、粗皮桉、丰桉、辐射桉、白皮桉、大花序桉10种桉树进一步造林试验,结果表明：2a生的平均保存率以丰桉最高,达84.5％,其次是柳桉、粗皮桉、邓恩桉、赤桉、巨桉,较差的为本沁桉、辐射桉、白皮桉三种。树高生长情况来看邓恩桉、丰桉、巨桉、本沁桉、赤桉、柳桉具有很好适应性,白皮桉、粗皮桉、大花序桉表现一般,辐射桉最差。胸径生长上,邓恩桉、本沁桉、巨桉和柳桉为生长比较大一类,表现一般的赤桉、粗皮桉和丰桉,较差的为白皮桉、大花序桉、辐射桉。同样2a和2.5a蓄积量上比较,邓恩桉、本沁桉、巨桉比平均值高,丰桉、柳桉、赤桉、粗皮桉、大花序桉、白皮桉均低于平均值。聚类分析可分三类：邓恩桉、本沁桉、巨桉、丰桉适应性强、速生的品种,而赤桉、粗皮桉、柳桉、白皮桉表现一般、大花序桉较差;其中邓恩桉最突出。不同桉树适应性与其抗寒性有关。 相似文献
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几种不同桉树在福建省中部区域引种适应性探讨 总被引：5，自引：0，他引：5
在福建省中部地区永安市分别进行尾巨桉、邓恩桉、尾细桉、赤桉等几种不同桉树引种栽植试验,调查它们当年的成活率、生长量、保存率、冻害状况和病虫害危害以及两年生和三年生的胸径和高生长量,比较分析上述几种树种3年生胸径、树高的生长。结果表明：邓恩桉在该地区有较好的年生长量和抗寒能力,尾巨桉、尾细桉生长量较高,但抗寒性较差,赤按有良好的抗寒性,但生长量较差。对于桉树北移栽植而言,极端低温是该树种的限制因子。在比较速生性状的同时,应考虑它的抗寒性状。该试验结果表明,邓恩桉在该区域引种栽培是较理想的选择树种,可减少按树在该区域投资风险,为生产提供科学的理论依据。 相似文献
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以尾巨桉(Eucalyptus urophylla×E. grandis) 3种不同造林密度(A密度:1 666株/hm~2,B密度:1 250株/hm~2,C密度:833株/hm~2)林分为研究对象,分析了1.5~5.5年生时不同密度林分生长动态、差异及林木分化特征,目的是为尾巨桉纸浆材、胶合板材或大径级锯材人工林培育提供参考依据。3种密度林分树高连年生长量排序是CBA,胸径、单株材积连年生长量的排序与树高相同;而不同密度林分蓄积连年生长量的排序则相反。3种密度间尾巨桉林分树高、胸径、单株材积、蓄积量均有显著差异;密度A、B、C的林木胸径变动系数分别是12%、15%、15%,最大与最小变动系数间仅相差3个百分点;林分树高与胸径之比值中,林龄5.5年时最大比值(B密度,比值为140.7)比最小比值(C密度,比值为134.8)仅大4.2%。分析表明,林分树高、胸径、单株材积连年生长量随密度增加而减小,林分蓄积连年生长量则随密度增加而增大;密度小的林分平均树高、胸径、单株材积显著高于密度大的林分,但密度小林分蓄积量则显著低于密度大的林分;林木分化及林木圆满度在不同造林密度间差异较小,且无明显规律。 相似文献
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以尾巨桉(Eucalyptus urophylla×E.grandis)无性系为造林品系,设计了5种不同造林密度和6种不同施肥组合进行造林示范,对43个月生不同造林措施示范林生长量进行分析。结果表明,尾巨桉无性系林分树高、胸径、单株材积生长量随林分密度的增加而减小,但林分蓄积量则有随林分密度的增加而增大趋势,最高密度的林分蓄积量最大,达129.28 m3/hm2;造林后追肥可明显促进林木生长,追肥的林分蓄积生长量是不追肥的166.7%,并且以追肥用量大的林木生长效果更好;在造林后1个月及时追肥情况下,可选用磷肥或复合肥作基肥。 相似文献
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林分密度对邓恩桉生物产量及生产力的影响 总被引：1，自引：0，他引：1
对湘南低山丘岗区密度为1 110、1 667和2 500株.hm-2的8年生邓恩桉Eucalyptus dunnii丰产示范林生物量进行了测定.结果表明:单株生物量随林分密度的增加而明显减小,低密度林分林木平均木的生物量是高密度林分的1.22倍;林分生物量随林分密度的增加而增加,高密度林分比低密度林分高出271.26 t.hm-2;各密度林分的年均净生物量分别为32.35、43.97和59.51 t.hm-2a-1,高于杉木中心产区杉木人工林的水平,林分各组分的生物量随林分密度的增大而增大,并出现干>根>枝>皮>叶的规律;林分结构以中密度林分合理,叶面积指数高,干材生物量达61%以上.邓恩桉在湘南低山丘岗区发展潜力大,可作为该地区短周期工业用材林培育造林树种. 相似文献
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尾叶桉,巨尾桉木材密度及木材抽提物含量的研究 总被引：2，自引：0，他引：2
对广西东门林场的２．５年生尾叶桉和巨尾桉的候选优树取样测定分析发现，两个树种和树间的木材密度及木材抽提物含量均存在显著差异。材南均匀度方面，来自巴西阿拉克鲁兹公司的高度选择改良的无性系杂交种子园的巨尾桉的材质均匀度远锭高于未经选择改良的尾叶桉，说明亲本的材质选育是成功有效的，尾叶桉不同单优树之间材性差异巨大，具有很大的改良潜力，相关回归分析还发现木材密度、木材抽提物含量及树木生长率间缺乏相关关系， 相似文献
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Ze-Hui Jiang Xiao-Qing Wang Ben-Hua Fei Hai-Qing Ren Xing-E. Liu 《Annals of Forest Science》2007,64(8):807-814
The effect of stand density (1000 stems/ha, 500 stems/ha and 250 stems/ha) on tree growth and wood quality characteristics was studied in a 27-year-old plantation species of Populus xiaohei in China. Results indicated that stand density had significant effects on tree radial growth and crown size, and the lowest stand density produced trees with the largest stem taper. In terms of wood quality characteristics, there was no significant effect of stand density on either wood basic density or fiber length. However, significant differences were found between different stand densities for wood mechanical properties. A positive relationship between modulus of elasticity, compression strength and stand density was observed, while the highest modulus of rupture was recorded at a moderate density of 500 stems/ha. Stand density was responsible for highly significant effects on both juvenile wood and wet heartwood basal areas in individual trees, and there was an obvious tendency towards increasing juvenile wood and wet heartwood basal areas with decreasing stand density. In addition, the relationships between wood quality characteristics and tree and stand characteristics were also examined. Some wood quality characteristics, namely mechanical properties and juvenile wood and wet heartwood basal areas, were quantified successfully in relation to selected tree characteristics using a regression approach with various degrees of goodness of fit. Based on comprehensive consideration of various factors, such as wood quality, tree growth, and establishment cost, results from this study suggest that a density of 500 stems/ha is optimum for wood production. 相似文献
13.
Analyses of land snails and habitat factors in acid beech forests were conducted in southern Germany (northern Bavaria). The
objectives were to study the effects of habitat characteristics on snail density and species richness. Habitat structures
were determined for 37 plots in one big forest. We found a significant relationship between the number of snail species and
individuals and the following set of habitat factors coverage of herbaceous layer, growing stock, mean diameter at breast
height of the three largest trees (DBHmax), stand age, total dead wood volume per ha, and advanced decomposed dead wood volume
per ha. We use maximally selected rank statistics to estimate cutpoints separating stands with low densities, from stands
with high snail densities. Here, we define cutpoints for a significant higher snail density at a stand age of 187 years, 57 m3/ha dead wood, 40 m3/ha advanced decomposed dead wood, 63 cm DBHmax and more than 1% herbaceous layer. For species richness, cutpoints are estimated
at 338 m3/ha stand volume, 170 years stand age, 50 m3/ha total dead wood amount, 15 m3/ha advanced decomposed dead wood and 56 cm DBHmax. The microhabitat analysis shows a higher pH value and a higher Calcium
content at the bottom of large snags and under large lying dead wood pieces in comparison to litter, upper mineral soil and
at the bottom of vital living trees. Snail species and individual density are significantly linked to these patterns of chemical
parameters. The identified cutpoints are a good base for ecological management decisions in forest management. 相似文献
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《Southern Forests》2013,75(2):81-89
The aim of this study was to develop a stand-level growth and yield model for short-rotation Eucalyptus grandis grown for pulp wood production at Piggs Peak in Swaziland. The data were derived from a Nelder 1a spacing trial established with E. grandis clonal cuttings in 1998 and terminated in 2005. Planting density ranged from almost free-growing trees established at 161 trees ha?1 to extremely dense stands at 6 809 trees ha?1. Functions were fitted to describe stand density, dominant height and basal area development over time. The functions performed well when scrutinised for their goodness of fit. They were also found to be consistent with forest growth theory when their logical behaviour was tested over the range of planting densities. 相似文献
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马尾松无性系种子园半同胞子代变异分析和家系选择 总被引：13，自引：0，他引：13
以福建省漳平五一林场马尾松无性系种子园自由授粉子代半同胞家系为研究对象,分析其树高、胸径、材积、冠幅、通直度、高径比、冠径比、木材基本密度、管胞长度和宽度、管胞长宽比等性状,发现家系间除管胞长宽比性状差异显著,其余性状均达差异极显著,暗示着马尾松种子园半同胞家系间存在较为丰富的变异,具选育潜力。8年生林分内各性状的家系遗传力以树高性状为最高(0·691),其次是木材基本密度(0·640)。各性状间的相关性分析结果表明,生长量性状的改良可间接改善通直度,且生长量性状与木材基本密度存在显著正相关关系,木材基本密度与管胞长度和宽度不相关。采用10%入选率,发现5年生林分和8年生林分入选家系一致,材积遗传增益分别达19·74%和19·23%,且5年生林分和8年生林分生长量性状的遗传相关极显著,认为马尾松制浆造纸材短轮伐期的初选年龄可确定为5年生;根据性状遗传力的相对大小和典型相关分析的结果,认为马尾松家系选择可适当注重树高生长量指标。以树高和材积为选择指标,按照10%入选率,兼顾材性和种子园内无性系的开花结实情况,筛选出制浆造纸材短轮伐期优良家系12个。 相似文献
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《Forest Ecology and Management》1997,98(1):49-60
A red alder planting spacing study was used to compare three modeling approaches that have been successfully used for other tree species. These three approaches predict stand structure and dynamics in plantations that are 7 to 16 years old, with planting densities of 976 to 13 899 trees/ha. The diameter-distribution-prediction approach tended to over-predict the diameter at breast height (dbh) for larger trees in stands planted at low density and to under-predict dbh for smaller trees in stands planted at high density. This approach may be useful for comparing planting densities when a tree list is not available. The stand-table-projection approach tended to under-predict dbh for smaller trees in young stands planted at low density and to over-predict dbh for smaller trees in young stands planted at high density. This approach, however, provided consistency between stand- and tree-level growth projections, and should be useful for comparing planting densities when a tree list is available. The individual-tree-growth approach provided the best representations of observed diameter distributions at all planting densities, stand ages, and growth intervals. This approach may be best suited for stands that have been thinned, stands with mixtures of species, and stands with heterogeneous size classes. 相似文献
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杉木无性系生长和材性变异及多性状指数选择 总被引：11，自引：0，他引：11
对19年生和17年生2块杉木无性系测定林开展生长和材性变异及多性状指数选择研究,其中,19年生测定林包括38个参试无性系,17年生测定林包括102个参试无性系。2块测定林数据分析结果均显示:无性系树高、胸径、单株材积、心材率和木材基本密度存在极显著的遗传差异,无性系重复力达中等偏上至较高水平,遗传变异系数各性状间差异较大;树高、胸径、材积生长性状间存在极显著的表型和遗传相关,与基本密度存在弱负相关。不同选择方法的结果表明,指数选择能整体提高单株材积、心材率和木材基本密度综合的遗传增益,达到比单性状选择更好的选择效果,是多性状改良较理想的选择方法。 相似文献
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林分密度对桉树幼龄能源林的影响 总被引：3，自引：0，他引：3
对0.5年生3种不同密度配置的幼龄尾巨桉优良无性系DH32-29各器官生物量、热值以及灰分进行了调查和测定,结果表明:所选3种密度间树高差异显著,基径差异达到极显著水平,随着密度的增加,树枝、叶片、树干的生物量分别呈现减少趋势,密度与树枝和树干生物量的相关性达到了0.01极显著水平;单株生物量随密度的增大而减小,林分生物量则相反;单株热值无显著差异,仅单株平均灰分含量高密度与中密度存在显著差异。综合分析,高密度0.25 m×2 m林分生物量最大,其灰分含量比低密度的林分低,适合作为能源林培育密度。 相似文献
19.
Variation of traits that include height, diameter at breast height (DBH), stem volume, crown width, straightness, wood basic
density, tracheid length and width of open-pollinated progenies from clonal seed orchard of Pinus massoniana was analyzed. Differences in traits such as growth, tree form and wood quality among families was significant, which indicated
that the improvement potential was notable. Heritability of height and wood basic density reached 0.691 and 0.640, respectively.
According to a correlation analysis between traits, stem straightness could be improved indirectly when growth traits are
improved; growth traits were significantly correlated with wood basic density; and wood basic density was not significantly
correlated with length and width of the tracheid. Under the selection ratio of 10%, genetic gains were 19.74% and 19.32% respectively,
and selected families from the progeny test stands at the age of five years and eight years were the same. Genetic correlation
of height, DBH and stem volume was also significant at the level of 0.01. These show that selection of the short rotation
of P. massoniana for pulp and paper use would be efficient for five-year-old trees. According to the comparison of the heritability of all
the traits and taking into account the result of canonical correlation analysis, height could be considered as the most important
index for selection. Given wood quality of all the families, and flowering and fruit settings of the clones in a seed orchard,
twelve fine families were selected at 10% selection ratio of height growth and stem volume.
Translated from Scientia Silvae Sinicae, 2005, 41(6): 43–49 [译自: 林业科学] 相似文献