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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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对13个桉树无性系的生长性状、木材纤维形态和化学组分等性能进行测定与分析,并经多性状综合评判,选择出生长量、生物量和纤维产量高且材质优良,可作为纤维材在闽南山地重点推广应用的优等无性系C1、C6、C9和C10,近4年生平均树高、胸径、杆材重量、纤维产量分别可达16.0 m、13.9 cm、47.5 kg.株-1和21.9 kg.株-1,木材基本密度、纤维长度、长宽比分别为0.569 g.cm-3、0.926 mm和56.3;选出生长量(产量)较高且材质优良的无性系有EC1、C2、C3、C4,这些无性系可根据闽南山地的具体立地条件有选择地应用。 相似文献
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利用乔木柳12年生无性系对比试验林的材料,研究了13个柳树无性系木材基本密度株内径向和纵向的变异模式,并对密度选择的时期和取样位置进行了探讨。结果表明:(1)在1.3m高度,乔木柳无性系各年轮组木材戏向变异多数为“M”型曲线,即从木芯向外第、至第3年轮组(1-6a)的木材密度逐渐增加,第4年轮组(7-8a)略有下降,第5年轮组(9-10a)又有明显增加,至最外侧年轮(11-12a)木材密度则显著下降,根据各无性系的变异特点,分成3种类型,其中无性系221的变异较为独特,为典型的“N”型;(2)乔木柳无性系生长期密度变化的规律为:1-2年生时木材基本密度相对较低,3-4a以后密度相对稳定并接近无性系加权平均密度,3-4年生时木材基本密度与5-12年生时的测定值相关系数为0.789-0.985,均达到极显著相关水平(α=0.01),5-12年生乔木柳无性系木材基本密度的变异为62.2%-97.0%与3-4年生时木材基本密度的值有关,3-4a作为5百木柳木材基本密度的选择年龄最为合适;(3)供试群体木材密度株内纵向变异模式大多也可用“M”型曲线加以描述,具典型的苴孔材绷向密度变异特征,根据各无性系的变异特点,分成4种变异类型;树干高1.3,3.6和7.2m处的木材基本密度与无性系平均密度的相关系数达到显著和极显著水平,可以在树干1.3m处取样以推测无性系平均值;(4)在供试群体中,有的无性系木材基本密度纵向和径向变异的幅度均很小,木材较为均一,如苏柳791,表明在乔木柳杂种后代中选择木材均一的柳树新品种是可能的。 相似文献
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经测试,(1)刚果12号桉W5无性系立木1.3m高处和3/4树高处的木材密度分别为475.994 444 kg/m3和465.955 555 kg/m3,1.3 m高处的木材密度比3/4树高处的木材密度大2.11%,经作t检验两者无显著差异,刚果12号桉W5无性系立木木材平均密度为471.0 kg/m3.(2)尾叶桉U6无性系立木1.3 m高处和3/4树高处的木材密度分别为438.955 556 kg/m3和428.816 667 kg/m3,1.3 m高处的木材密度比3/4树高处的木材密度大2.31%,经作t检验两者略有差异,尾叶桉U6无性系立木木材平均密度为433.911 111 kg/m3.(3)刚果12号桉W5无性系立木木材平均密度比尾叶桉U6无性系立木木材平均密度大8.55%,1.3m高处密度大8.44%,3/4树高处密度大8.66%,并经分别作t检验刚果12号桉W5无性系立木与尾叶桉U6无性系立木木材密度有明显的差异. 相似文献
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采用日本落叶松35个无性系苗木,另加2a混系扦插苗、2a实生苗、2a实生换床苗及长岭岗林场种子园2a实生苗进行造林试验,以早期选择出适应性强的无性系进行无性系造林并加以推广。试验方法采用完全随机区组排列,5次重复,每重复2排40个小区;小区设置为4株,造林规格2m×2m。7a生长调查结果表明:在胸径、树高生长方面有极显... 相似文献
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尾叶桉U6无性系林分密度效应研究 总被引:7,自引:0,他引:7
文章分析了造林密度对6年生尾叶桉U6无性系林分各生长因子的影响,结果表明:造林密度对桉树人工林各林分生长因子的影响显著性不同,密度与胸径、单株材积生长呈显著负相关关系,6年生U6无性系人工林平均胸径及平均单株材积生长量以密度D(1665株/hm^2)>C(2250株/hm^2)>B(2812株/hm^2)>A(3333株/hm^2)。密度对树高、林分蓄积量的生长均有一定影响,但差异不显著,林分平均树高生长量随着密度的增加而递减,林分蓄积量则以C处理最大,达153.9214m^3/hm^2;适宜造林密度范围在1536~2481株/hm^2之间。 相似文献
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以30块100 m×100 m的模拟样地为研究材料,从林木空间分布格局吻合率关系对模拟的小样方进行研究,并以1块100 m×100 m的实地调查样地为例,验证新确定样方的合理性和可行性;根据实际调查样地的调查时间来分析比较样方间的调查时间和成本,进而确定较优的样方面积和样方数.结果表明:(1)空间结构参数中的角尺度与抽取的样方面积大小和样方数量有关.随着样地面积的增大和样方数量的增加,所估计的林木空间结构均趋于稳定;(2)从林木空间格局来看,样方面积为10 m×10 m、15 m×15 m、20 m×20 m、25 m×25 m、30 m×30 m抽样数分别为42、23、12、9、4时,均能准确的表达林分的空间分布格局;(3)在考虑调查时间和成本时,样方面积为30 m×30 m、抽样数为4是林分空间结构调查时较适合样方调查面积和调查数. 相似文献
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对福建省洋口国有林场1994年营建的杉木无性系测定林的生长性状进行调查分析,结果表明:无性系16年生时平均树高、胸径、单株材积分别为13.19 m、14.59 cm、0.1339 m3;无性系树高、胸径、材积重复力达0.6873以上,生长性状受到中等强度的遗传控制。以16年生时材积为指标选出4个速生无性系,平均树高、胸径、单株立木材积分别为14.30 m、16.30 cm、0.17696 m3,遗传增益均值分别为13.03%、12.26%、33.26%。 相似文献
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采用 2 90块标准地调查资料 ,分析了 I- 6 9杨胶合板用材林的产量和生物量结构随立地指数和造林密度的变化规律。胶合板材产量随立地指数的增大而增大 ,且占总产量的百分比在立地指数为 14、16、18m时 ,随造林密度的增大而减小 ;当立地指数为 2 0 m和 2 2 m时 ,保持稳定在 50 %左右。磨木浆材和化学浆材产量随立地指数和密度的增大而增加。在立地指数为 14、16、18m时磨木浆材产量占总蓄积量的百分比和化学浆材产量占总蓄积的百分比均随造林密度的增大而增大 ;在立地指数为 2 0、2 2 m时则受造林密度的影响不大 ,分别保持在 30 %和 2 0 %左右。林分和单株的树干、树枝、树皮生物量组成比例均随立地指数、造林密度的变化无明显的差异。营造 I- 6 9杨胶合板用材林时选择立地指数 2 0、2 2 m的地段以及用造林密度 156 (8m× 8m)、2 0 4 (7m× 7m )株·hm-2 为最佳。 相似文献
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通过对2.5年生香樟组培幼态枝扦插无性系人工林和实生人工林,不同季节林木生长量、生物量及生产力进行对比研究,结果表明:香樟扦插无性系林树高、地径生长量比实生林具有优势;方差分析表明,香樟2种类型人工林树高在不同季节的生长差异经历"不显著-显著-极显著"的过程,而地径的生长差异不显著;2种类型香樟人工林四季的生长曲线符合Logistic数学方程的生长规律。2.5年生香樟实生林生物量达31 241.99 kg.hm-2,仅占无性系林的59.2%,净生产力的差异也相似;香樟无性系林分凋落物达9 145.45 kg.hm-2,是实生苗人工林的1.92倍。 相似文献
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杨树新无性系木材性质的变异研究 总被引:4,自引:0,他引:4
The wood basic density, cellulose content and fiber form were investigated for all sample trees at breast height (1.3m) in seven poplar clones, and at 0 (butt), 5.6, 9.6, 13.6, 17.6, 19.6 and 21.6 m for clone Nanlin-95 and Nanlin-895, respectively,for providing information on variation patterns of wood density, fiber characteristics and holocellulose content within trees and among clones. The results showed that significant variations about wood density, cellulose content, fiber diameter and the ratio of fiber length to diameter existed among poplar clones examined. Variance analysis indicated that there were significant differences in wood basic density, fiber length, fiber diameter and cellulose content among the growth rings, which had an increasing tendency along the direction from pith to bark. The significant differences also existed in wood basic density, fiber length and fiber diameter at different tree height. The mean wood basic density had a general increase trend with increasing height of trees and the lowest was found at the base, while fiber length and fiber diameter had a general decline pattern with increasing height of trees and the biggest value was observed at the height of 5.6 m. Regression analysis indicated that the relationship between examined wood properties and growth ring number (cambial age), and the relationship between examined wood properties and tree height can be described by polynomial functions. 相似文献
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不同造林技术措施对黎蒴幼林生长的影响 总被引:3,自引:0,他引:3
文章对韶关市翁源县林科所附近于2005年3月营造的12种不同造林技术措施黎蒴试验林进行研究,比较其中不同施肥措施、不同造林密度和不同整地规格下林木生长状况的差异,找出有利于黎蒴幼林生长的关键造林技术措施。研究结果表明:(1)12种不同造林技术措施下的树高、地径、冠幅等生长指标存在显著差异;(2)12号标准地树高生长显著高于其它标准地,8号标准地地径和冠幅生长最旺盛;(3)在不同施肥量的试验中,12号标准地黎蒴的生长最好;(4)在不同造林密度的试验中,8号标准地黎蒴的生长最好;(5)在不同整地规格的试验中,6号标准地黎蒴的生长最好;(6)聚类分析结果,将12个标准地林木的生长速度分为快、中和慢3种类型。 相似文献
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The effects of initial tree spacing on wood density at breast height were examined for 22-year-old Japanese larch (Larix kaempferi). The experiment involved the use of three plots with different initial tree spacing densities (300, 500, and 1000 trees/ha).
For five trees selected from each plot, the total tree height, diameter at breast height, height to the base of the live crown,
and crown diameter were measured. Ring width and wood density for individual growth rings were determined by X-ray densitometry.
A mixed-effects model was applied for fitting the radial variation in wood density in relation to initial spacing. Models
having various mean and covariance structures were tested in devising an appropriate wood density model. The model, consisting
of the mean structure with quadratic age effects and heterogeneous first-order autoregressive covariance, was able to describe
the radial variation in wood density. Closer spacing of trees (1000 trees/ha) resulted in a faster increase in wood density
from the pith outward than for more widely spaced trees, indicating that initial tree spacing may influence the age of transition
from juvenile to mature wood. 相似文献
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Roman Gebauer Daniel Volařík Josef Urban Isabella Børja Nina Elisabeth Nagy Toril Drabløs Eldhuset Paal Krokene 《European Journal of Forest Research》2014,133(1):111-120
Trees must respond to many environmental factors during their development, and light is one of the main stimuli regulating tree growth. Thinning of forest stands by selective tree removal is a common tool in forest management that increases light intensity. However, morphological and anatomical adaptations of individual shoots to the new environmental conditions created by thinning are still poorly understood. In this study, we evaluated shoot morphology (shoot length, needle number, projected leaf area) and anatomy (tracheid lumen area, tracheid number, tracheid dimensions, xylem area, potential hydraulic conductivity) in three Norway spruce (Picea abies/L./Karst.) families exposed to different thinning regimes. We compared shoot characteristics of upper-canopy (i.e. sun-exposed) and lower-canopy (i.e. shaded) current-year shoots in a control plot and a plot thinned to 50 % stand density the previous year. One tree per family was chosen in each treatment, and five shoots were taken per canopy position. We found that upper-canopy shoots in both plots had higher values than lower-canopy shoots for all studied parameters, except lumen roundness and tracheid frequency (i.e. tracheid number per xylem area). Thinning had little effect on shoot morphology and anatomy 1 year after thinning, except for small but significant changes in tracheid dimensions. Needles were more sensitive to altered light conditions, as projected leaf area of shoot, needle number and leaf hydraulic conductivity changed after thinning. Differences between upper- and lower-canopy shoots did not seem to be influenced by thinning and were almost the same in both plots. Our results suggest that lower-canopy shoots require several years to modify their morphology and anatomy to new light conditions following thinning. The slow light adaptation of the lower canopy may be of practical importance in forest management: thinned stands may be predisposed to drought stress because newly exposed shoots experience increased illumination and transpiration after thinning. 相似文献