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1.
The stem analysis ofBetula platyphylla in natural forest at the Maoershan Forest Experimental Station of Northeast Forestry University, showed that the growth variation
of the trees, including height and diameter breast height, decreases with the increase of the age. There is the turning point
for the growth variation of the tree from acute change to relative stability when the trees are in eighteen years old. There
are significant differences among the height, diameter and volume growth of the trees at that time. Therefore, the optimal
age for early selection of this species in natural stands is eighteen years old (18 a). Diameter is used as main index for
selection and height growth as auxiliary one.
(Responsible Editor: Zhu Hong) 相似文献
2.
福建永安光皮桦种源家系试验初报 总被引：3，自引：0，他引：3
应用采自南方5省区光皮桦(Betula luminiferaH.Winkl.)天然林的12个种源176个家系种子在福建永安进行了苗期测定,并在3个不同海拔高度开展造林试验,调查其1年生幼林的树高、地径,据此对优良种源、家系进行了初步选择。结果表明:光皮桦苗期高生长在种源家系间差异显著;1年生幼林各种源、家系、海拔间树高和地径差异均极显著,种源和海拔的交互作用对树高影响极显著,而对地径影响不显著;种源遗传力高于家系,树高遗传力高于地径;以树高为主要指标,初步筛选出适合当地生长的5个优良种源,并选择出适合不同海拔的优良家系各30个,其种源遗传增益达13.27%,家系遗传增益为12.84%,选择效果良好。 相似文献
3.
Katherine D. Heineman Ethan JensenAutumn Shapland Brett BogenriefSylvester Tan Richard RebarberSabrina E. Russo 《Forest Ecology and Management》2011,261(11):1820-1832
Tree height and crown allometries reflect adaptations for resource acquisition and structural stability, as well as plastic responses to a heterogeneous environment. While both light and soil resources limit growth and influence competitive responses in tropical forests, the effects of belowground resources on allometries are less understood, especially within the understory. To characterize outcomes of tree competition along an edaphic resource gradient, we quantified variation in height and crown allometries of six Bornean tree species from contrasting regeneration niches (light-demanding vs. shade-tolerant) on two soil habitats (clay-fine loam and sandy loam) within a 52-ha forest dynamics plot. Using empirically-fit allometric parameters and diameter growth rates from plot census data, we modeled tree height and crown area growth over the projected life span of each species. Based on resource competition theory, we hypothesized that tree species specializing on and populations of generalist species growing on the relatively moister, more fertile clay-fine loam soil habitat would have faster height and crown growth rates, compared to those on the sandy loam habitat, regardless of regeneration niche. Among soil specialists and within generalists of both genera, trees growing on clay-fine loam had taller stems and larger crowns at a given age and faster height and crown area growth rates at most sizes than trees on sandy loam. Differences in height and crown growth were driven by the faster diameter growth rates of trees on clay-fine loam, not by differences in height- and crown-diameter allometries, as trees on sandy loam were significantly taller at a given diameter, and differences in crown allometry were not consistent across soil habitats. Characterizing the height and crown growth responses of trees along resource gradients provides insight into the mechanisms that maintain diversity in tropical forests. Our results point to the importance of adaptive and plastic responses to both above and belowground resource availability in determining the allometric growth of trees and suggest that this diversity of responses may contribute tree species coexistence through competition-based trade-off mechanisms and variation in growth among individuals. Additionally, as the importance estimating natural carbon sequestration increases with the escalating effects of anthropogenic climate change, differences in tree growth and architecture across soil habitats also have implications for the approximation of forest carbon storage on heterogeneous tropical soils. 相似文献
4.
笔者以日本落叶松二代优树嫁接苗为对象,对嫁接成活率和嫁接苗生长情况进行调查分析,结果表明:二代优树嫁接成活率平均值为36.40%;无性系间嫁接成活率和生长量差异较大,无性系内各单株生长差异大,变异系数最大达到72.49%;家系间嫁接成活率存在极显著差异,生长量差异不显著;第3 a生主梢长度与2 a苗高存在极显著正相关,用2 a苗高对第3 a苗高生长进行校正后发现家系间第3 a苗高生长存在显著差异;不同树龄母树穗条的嫁接成活率及嫁接后苗木生长情况均存在极显著差异,采穗母树年龄为10～12 a的嫁接苗嫁接成活率、苗高和地径生长量均大于采穗母树年龄为14～17,18～20 a的嫁接苗。 相似文献
5.
2014年8月,对高州市红椎等7种阔叶树种早期生长状况进行了调查,结果表明,3个林龄（4年、3年和2年生）红椎树高生长较快,其次为台湾相思,而香樟早期树高生长较慢;3个林龄红椎、枫香及红花荷地径生长较快,同样香樟地径生长较慢。方差分析表明,同一树种树高在4年和3年生间差异不显著（P＞0.05）,表明3年~4年生红椎等7种阔叶树种树高生长不明显,却显著高于2年生（P＜0.05）;除枫香、红花荷、台湾相思外,其余各树种3个林龄间地径均存在显著差异（P＜0.05）。3个林龄树高下坡/上坡均值分别为1.43（4年生）、1.48（3年生）和1.24（2年生）,而地径下坡/上坡均值分别为1.21（4年生）、1.32（3年生）和1.32（2年生）,阔叶树种在下坡生长状况明显高于上坡。本研究为阔叶树种树种选择及可持续经营提供科学参考。 相似文献
6.
Increases in plant size and structural complexity with increasing age have important implications for water flow through trees. Water supply to the crown is influenced by both the cross-sectional area and the permeability of sapwood. It has been hypothesized that hydraulic conductivity within sapwood increases with age. We investigated changes in sapwood permeability (k) and anatomy with tree age and height in the broad-leaved evergreen species Eucalyptus regnans F. Muell. Sapwood was sampled at breast height from trees ranging from 8 to 240 years old, and at three height positions on the main stem of 8-year-old trees. Variation in k was not significant among sampling height positions in young trees. However, k at breast height increased with tree age. This was related to increases in both vessel frequency and vessel diameter, resulting in a greater proportion of sapwood being occupied by vessel lumina. Sapwood hydraulic conductivity (the product of k and sapwood area) also increased with increasing tree age. However, at the stand level, there was a decrease in forest sapwood hydraulic conductivity with increasing stand age, because of a decrease in the number of trees per hectare. Across all ages, there were significant relationships between k and anatomy, with individual anatomical characteristics explaining 33-62% of the variation in k. There was also strong agreement between measured k and permeability predicted by the Hagen-Poiseuille equation. The results support the hypothesis of an increase in sapwood permeability at breast height with age. Further measurements are required to confirm this result at other height positions in older trees. The significance of tree-level changes in sapwood permeability for stand-level water relations is discussed. 相似文献
7.
油松管胞形态特征的变异 总被引：13，自引：0，他引：13
本文研究分析了山西中条山产地油松管胞形态特征的变异。管胞长度自髓心向外,首先迅速增加,13年后管胞长度增加缓慢,20年后保持相对稳定。管胞长度沿树干主轴自基部向上逐渐增加,5.3m高处最长,然后向上变短,树冠区域管胞长度最短。形成层原始细胞长度随着原始细胞年增大,开始递增,达到最大值后又递减。管胞直径、胞壁厚度自髓心向外增加。管胞直径轴向变化由树干基部开始向上增大,然后又减小。管胞长宽比、壁腔比的径向变异与管胞长度的径向变异模式相似。生长轮内管胞长度从早材到晚材,开始减小,然后增加,最小值位于早晚材过渡处。 相似文献
8.
本文对３０年生９０株人工长白落叶松树干解析生长变异及早期预测进行了研究，结果表明，树高、胸径、材积的变异随着年龄增大而减小，１４～１８龄是生长变异由剧烈分化到趋向稳定的转折年龄，此时树高、胸径、材积等的幼龄至成熟龄相关达极显著水平，选择效率也处在较高水平，确定长白落叶松早期选择年龄为１４年。 相似文献
9.
2013年11月,课题组在闽西北地区(明溪县、将乐县和宁化县境内)采用逐一踏查与询问的方式对光皮梾木(Cornus wilsoniana)进行了较为详细的资源调查.结果发现:闽西北地区存在天然光皮梾木种群,分布非常有限;现存光皮梾木包括树龄在100 a以上的散生古树和天然小群体两种分布类型;共收集闽西北地区光皮梾木种质资源(优树)24份,其中收集种子并成功育苗的有11个家系;方差分析结果表明,1 a生苗木平均苗高在家系间差异较小,家系间平均地径差异极显著(P<0.01),地径较大的前3个家系为滴水3、都尞1和滴水2.闽西北地区光皮梾木珍贵野生植物资源亟待保护、利用和开发. 相似文献
10.
Nishtman Hatami Peter Lohmander Mohammad Hadi Moayeri Soleiman Mohammadi Limaei 《林业研究》2020,31(1):99-106
The aim of this study was to develop and test a new basal area growth model in mixed species continuous cover forests in northern Iran.Weanalyzed 421 core samples from 6 main species in the forest area to develop our growth model.In each plot,we measured variables such as total tree height(m),diameter at breast height(DBH)(cm)and basal area of larger trees as cumulative basal areas of trees(GCUM)ofDBH[5 cm.The empirical data were analyzed using regression analysis.There was a statistically significant nonlinear function between the annual basal area increment,as the dependent variable,and the basal area of the individual trees and competition as explanatory variables.Reference area from the largest trees,was circular plot with area of 0.1 ha.GCUM was estimated for trees of DBH>5 cm.Furthermore,we investigated the dependencies of diameter growth of different species on stand density at different levels of competition,and diameter development of individual trees through time.The results indicate that competition caused by larger neighborhood trees has a negative effect on growth.In addition,the maximum diameter increment is affected by competition level.Therefore,the maximum diameter increment of species occurs when the trees are about 35–40 cm in dense-forest(40 to 0 m^2 per ha)and when the trees are about 60 to 70 cm in very dense forest(60 to 0 m^2 per ha)which is more likely to Caspian natural forests with high level density due to uneven-aged composition of stands. 相似文献
11.
IntroduttionMongoIianoak(QucI.cIIS))I()lIg()lIt.uFiscl1.etTurcz.)standsconstitutethelargesttypeoftI1esecondarytbrestinHeilongiiangProvince-CI1ina(llu'l979).Tl1el99IstatisticsoftheAdministrativeBtIreatIofForestRe-sourcesfOrHeilongiiangProvinceindicatedanes… 相似文献
12.
对11年生飞播马尾松林进行综合抚育间伐试验的结果表明,不同的间伐强度和次数均产生不同的效果。胸径生长以间伐强度大和2次间伐为好;树干形质以间伐强度小为好;间伐对树高、冠幅、林木分化等均有影响。 相似文献
13.
14.
以1994年种植在广东省龙眼洞林场的马占相思人工林为材料,调查5,10和15a生的树高、胸径和蓄积量,研究海拔和造林密度对生长量的影响。结果表明,海拔（0～500mm）对马占相思胸径生长无显著影响,但对5a生的树高、5和10a生的蓄积量有显著影响,其中250m〈海拔≤500m时的林分蓄积量最大;3种造林密度（800,1335和1998株／hm^2）对树高、胸径和蓄积量有较大影响,以造林密度为1335彬hm^2的林分蓄积量增长最快。林分内存在不同程度的海拔与造林密度交互作用,这种互作对胸径和蓄积量的影响逐年增强．但在15a生时对树高的影响已．不鼹薯． 相似文献
15.
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
16.
Seeds of 23 relic Metasequoia glyptostroboides trees were randomly collected from their original, natural populations found in Lichuan City, Hubei Province, China. The seed characteristics and growth of their three-year-old progenies were investigated. Results show that the average intra-family coefficient of variation (CV) in height growth of the 23 three-year-old families was 14.53%, slightly higher than that of the inter-family CV (14.02%). Correspondingly, these two parameters for root-collar diameter growth were 15.44% and 13.15%. The 23 relic mother trees were significantly differed in their general combining abilities (GCA) and relative effect values of GCA (RGCA) of height growth and root-collar diameter growth over the three years. Both height and root-collar diameter growth had high family heritability in this seedling stage. After eliminating two inferior families, i.e., 15 and 46, 2.21% of genetic gain in height growth was obtained and 1.50% in root-collar diameter growth. It was also significantly different in crown size and number of branches among the 23 three-year-old seedling families. From a cluster analysis we concluded that eight families, i.e., 23, 28, 29, 30, 31, 33, 35 and 44 displayed superior GCA and RGCA in both height and root-collar diameter growth. Therefore, these relic mother trees displayed their potential as parents in seed orchards. With the exception of family 23, the other seven superior families were all collected at Guihua Village, Zhonglu Town, Lichuan City, which has been identified as an optimum district of M. glyptostroboides for seed collection. 相似文献
17.
18.
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
19.
