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1.
对火炬松(PinustaedaL.)速生材5个高度木材的基本密度、年轮宽度、生长率、晚材率和管胞弦壁纤丝角进行系统测量、统计和分析,结果表明,木材基本密度随树干高度的增加而降低.但各高度之间的差异不显著;生长率从髓心向外,南北方向都是随年轮数的增加而减小,在高度上是随树干高度的增加而增大.但其差异性均不显著.晚材率与木材基本密度呈线性正相关,与纤丝角呈线性负相关;木材基本密度与纤丝角呈负相关;纤丝角与生长率呈正相关.其相关显著性均随树干高度的增加而减弱.这些规律,为火炬松速生材的有效利用和林木生长调控提供了理论依据.  相似文献   

2.
MITCHELL  M. D.; DENNE  M. P. 《Forestry》1997,70(1):47-60
The influences of cambial age and ring width on density of Sitkaspruce (Picea sitchensis (Bong.) Carr) were analysed in relationto within-tree trends in tracheid diameter and cell wall thickness.Discs were sampled at breast height from a total of 24 trees,from seven stands at three contrasting sites in Wales, and atbreast height, 30 per cent and 60 per cent total tree heightfrom one of the stands. Across the juvenile wood, ring density decreased with ring numberfrom the pith while radial tracheid diameter increased. Theseoverall trends were considered to be inherent to tree growth,presumably associated with cambial ageing, since they occurredin all trees on all sites. In juvenile wood, density also variedwith site growth rate (as indicated by ring width) at similarcambial age, wider rings being associated with more rapidrateof change in tracheid diameter with ring number and with decreasein tracheid wall thickness. Consequently, on a site having treeswith high growth rate density decreased more rapidly acrossthe juvenile wood, down to a lower minimum value, than on siteswith a slower growth rate. In mature wood, the decrease in densitywith increase in ring width was associated with differencesin both tracheid diameter and wall thickness. Density was slightly(though not significantly) higher at breast height than in comparablerings at 30 per cent total height, associated with significantlythicker tracheid walls at breast height. Changes in radial tracheid diameter (with ring number, or withring width) were associated with greater differences in theearlywood than towards the latewood end of each growth ring,while variations in wall thickness with ring width were associatedwith rate of increase in wall thickness towards the latewoodend. This may account for some previously conflicting reportson influence of silvicultural management on density, for densityis likely to vary with influence of environment on the seasonalcycle of cambial activity. The extent of the juvenile wood as delimited by the inner coreof wide growth rings does not necessarily correspond to theregion of varying tracheid dimensions in Sitka spruce.  相似文献   

3.
幼龄材范围的确定及树木生长速率对幼龄材生长量的影响   总被引:8,自引:1,他引:8  
刘元 《林业科学》1997,33(5):418-426
本文以杉木、日本落叶松的人上林和天然林木材为对象,选择y=a+blnx回归模式。利用其管胞特征因子随年轮数的变化,研究划分幼龄材年轮界限的最适因子,并就生长速率对幼龄材生长量的影响进入了探讨。结果表明:杉木和日本落叶松的人工林及天然林木的管胞特征值在径向水平上的变化均遵循y=a+blnx模式,尤其管胞长度与年轮数回归的相关系数R均达0.98以上;管胞长度与管胞宽度及纤丝用相比,遗传率最大,随年轮数变化的模式最稳定,是划分幼龄材界限的最佳因子,由此得出杉木人工林幼龄材界限年轮为20-22(距髓心距离为12.9-13.2cm)、天然林为16-18(4.1-4.5cm),日本落叶松人工林为19-23(8.7-10.5cm)、天然林为23-24(2.9-3.1cm);幼龄材生长量与树木生长速率成正比。  相似文献   

4.
A comprehensive analysis on the variation pattern of early- and latewood tracheid morphological parameters along tree (Cunninghamia lanceolata Hook.) height, including length and width, wall thickness, tissue proportion, cell wall percentage, width of growth rings, and on the relationship among them are conducted. The results indicate an initially rapid and then gentle increase of tracheid length and width, thickness of the radial wall and tangential wall of tracheid, area percentage of tracheid from pith to outward, while S2 microfibril angle (Mfa) of tracheid, and rays percentage gradually decrease and then tend to be stable. The variation of all anatomical parameters but earlywood cell wall thickness shows no significance along tree height. The radial variation pattern of width of growth rings is characterized with initially slight decrease followed immediately by a rapid and then much more gentle increase from pith to outward. The delimitation age between juvenile and mature wood is 14-16 years. Com  相似文献   

5.
Summary Radial pattern of variation in the first-formed earlywood tracheid length in blue pine shows that it increases outwards from the pith at first rapidly up to the 10th ring, then more slowly up to about the 40th ring and thereafter it remains more or less constant. It is correlated significantly and positively with both age and distance from the pith up to 40 years. In the mature wood zone i.e. after 40 years, tracheid length is not affected by either age or distance from the pith. The mean tracheid length of mature wood is significantly and positively correlated with the mean tracheid length of juvenile wood and also with the tracheid length of each of the juvenile wood rings. Based on the results of this study some guidelines for sampling are proposed. Trees with greater than 51 cm d.b.h. or above 40 years of age can be compared by sampling only four outermost consecutive mature wood annual rings; and those with less than 51 cm d.b.h. or below 40 years of age can be compared by sampling any of the juvenile wood rings.A part of Ph. D. thesis submitted to Himachal Pradesh University, Simla-171 005 (India), under the supervision of Dr. K. K. Jain, Associate Professor. The author is thankful to Dr. Jain for constant encouragement and to the University Grants Commission (India) for financial assistance  相似文献   

6.
火炬松纸浆林材性变异和优质原料培育期的确定*   总被引:6,自引:2,他引:6       下载免费PDF全文
16年生火炬松纸浆材性状研究表明:管胞长度径向呈递增稳定的模式,纵向呈递减变化;其长宽比变异类似于管胞长度的变化;管胞长度变化范围为1.403~4.456mm,长宽比为46.7~70.1,腔径比为0.711~0.786,壁腔比为0.381~0.496。基本密度径向由0.324g/cm3递增到0.428g/cm3;纵向递减,其均值变动于0.314~0.401g/cm2;株间木材密度均值与管胞长度两性状不相关。纤维素含量由髓心附近37.04%递增到树皮附近43.91%,木素、多缩戊糖含量分别由28.78%、14.59%递减到25.74%、12.05%,其苯醇抽出物含量变化在2.12%~8.38%之间。火炬松木材幼龄期约为10~13a。基于火炬松木材各树龄材性的变化,结合生长量指标,确定其短周期纸浆林适宜采伐树龄约为12~13a。  相似文献   

7.
The annual ring width, density and shrinkage variation from pith to bark in Chinese fir (Cunninghamia lanceolata) and Boka sugi (Cryptomeria japonicd) were studied and compared. The results show that the ring width decreased sharply from pith to bark for Chinese fir. However, the ring width variation pattern for Boka sugi followed a different way, i.e., the ring width decreased to the fifth ring, increased to the tenth ring, decreased again to the fifteenth, and then increased to the twentieth, where it became constant. The large variations of Boka sugi appeared to show the maintenance of fast growth for many years. The annual ring mean density of Chinese fir increased gradually from pith to bark. However, the density changes for Boka sugi indicated the opposite trend, i.e., the mean density decreased gradually from pith to bark. The former showed a pattern as the same as a pine and a larch, and the latter was often found in a cedar and a cypress. The longitudinal shrinkage in juvenile wood was much hig  相似文献   

8.
油松管胞形态特征的变异   总被引:13,自引:0,他引:13  
徐有明 《林业科学》1990,26(4):337-343
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   

9.
The variation in the basic‐density level of 45 stems of Sitka spruce from two Danish sites has been examined. It is shown that the basic‐density level, i.e. the basic density as a function of ring width, within the juvenile wood decreases with (1) increasing distance from the pith and (2) increasing height in the stem (same ring number from pith provided). Furthermore, the basic‐density level seems to decrease with increasing stand quality, which may affect the pattern of variation in basic‐density level if the stand quality class varies with age. The basic density of the juvenile wood is markedly higher in Sitka spruce than in Norway spruce, whereby the risk of stem cracks probably is reduced.  相似文献   

10.
To examine the differences between juvenile and mature wood, 12 aged sample trees from two areas of Nagano Prefecture were harvested; and the radial development of tracheid length, the ring density, and the relation of the radial growth rate (observed by ring width) with some selected indices of ring structure were investigated. The results proved that the radial variation of tracheid length with ring number can be described by a logarithmic formula, and both plantations reached the demarcation of juvenile and mature wood at age 18. With the segmented regression method, we also analyzed radial variation of mean density and found that the demarcation of juvenile and mature wood was at age 15 for sample trees from Saku and at age 21 for those from Yabuhara. By using the results of estimates from juvenile and mature wood based on ring density, we found that high growth rates resulted when producing lower-density wood during the juvenile period, but these rates did not occur during the mature period. The basic reason for this phenomenon is the variation in patterns of earlywood and latewood in juvenile and mature wood, respectively. This result advised us that when managing plantations of Japanese larch it is necessary to take different measurements at different growth periods.  相似文献   

11.
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   

12.
马尾松人工林管胞长度的株间和株内变异   总被引:1,自引:1,他引:1       下载免费PDF全文
林木株间变异和株内变异是木材的两个主要变异来源,由于木材性状具有较强的遗传性以及育林措施对木材的可塑性,人们可以培育出材质优异的木材,然而因变异的存在,在如何充分利用木材时却遇到了许多困难。林学家的一个主要目的就是在充分掌握木材变异规律的基础上,采用有效方法提高材质的均匀性。  相似文献   

13.
Clonal variability among trees has been studied and found to have profound effects on nearly all measured phenotypes. However, when estimating wood properties it is important to consider variability within the tree. The position in which a tree is sampled could have a large influence on biomass characterization. We looked at variability in lignin content as height increases and as the number of rings from the pith increase in Populus species. Seven trees were destructively sampled; subsamples were obtained along a 2.4 m length of each stem and across increment rings. All samples were analyzed by pyrolysis molecular beam mass spectroscopy to map the variability across sampling heights and/or ring positions in lignin content. The results of this study indicate that when sampling a tree, there is more variability from ring to ring than at different heights going up the stem.  相似文献   

14.
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  
方升佐  杨文忠 《林业研究》2003,14(4):263-268
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   

15.

Wood density and tracheid length are two traits that significantly affect wood products. Genetic correlations were estimated to evaluate the effect on these traits from a selection for traits included in the Swedish Pinus sylvestris L. breeding programme. Measurements from a non-contiguous single-tree plot progeny trial with controlled matings between 30 parent trees was used. Heritabilities were high for the wood traits, intermediate for the growth capacity traits and low for the stem traits, with the exception of branch angle. Wood density showed no or non-significant negative genetic correlations with the growth capacity traits and a positive correlation with relative branch diameter. Tracheid length showed positive genetic correlations with height and a positive correlation with relative branch diameter. A selection that increased height growth at the age of 13 yrs by 10% was expected to decrease mean wood density at 33 yrs by 1%. The expected correlated response to tracheid length from the same selection was a 3% increase in the juvenile and mature wood.  相似文献   

16.
杨树微纤丝角的变异及其与木材性质的相关关系   总被引:6,自引:0,他引:6  
微纤丝角为细胞次生壁S2层微纤丝排列方向与细胞主轴所形成的夹角,与木材的物理性质、力学性质和化学性质都有着直接的关系。应用x射线衍射法测定了7个杨树无性系(14株样木)胸径处各年轮的微纤丝角,并对应分析和测定了各年轮的木材基本密度、纤维长度、纤维宽度和纤维素含量。研究结果表明,杨树微纤丝角在年轮间存在显著差异,其径向变异规律为从髓心向外以微纤丝角逐渐降低,年轮间的平均微纤丝角在7.8旱?8褐洌荒静幕久芏取⑾宋ざ取⑾宋矶群拖宋睾吭谀曷旨湟泊嬖谙灾钜臁O喙胤治霰砻鳎⑾怂拷怯肽静幕久芏取⑾宋ざ取⑾宋矶群拖宋睾看嬖谙灾母合喙毓叵??0.01),相关系数分别为-0.450、-0.586、-0.516和-0.660。回归分析结果表明,多项式方程可较好地描述杨树微纤丝角与所测定的木材性质的关系,相关系数均在-0.45以上(n=125)。本文的研究结果认为,在今后针对杨树材性改良的育种计划中,微纤丝角是一个重要的选育和改良指标。图3表3参34。  相似文献   

17.
为了解邓恩桉的木材性质,本研究采用排水法和《GB/T 1930-2009》方法测定邓恩桉的生材含水率、年轮宽度以及木材密度。结果表明:全树生材含水率、年轮宽度、生材密度和基本密度均值分别为114.61%、4.73 mm、1.164 g·cm-3、0.522 g·cm-3。随着树高的增加,年轮宽度、木材密度呈-大-小-大‖趋势,生材含水率呈-小-大-小‖趋势;由髓心向外,木材密度逐渐减小,生材含水率逐渐增大,年轮宽度先增加后减小。4个材性指标在树干径向不同位置间差异极显著,在不同树高间差异不显著(除年轮宽度外)。基本密度与3个材性指标间存在极显著或显著相关。  相似文献   

18.
研究了 4种不同营养元素的施肥处理对马尾松近熟林木材基本性质的影响。结果表明 ,在不同施肥处理后的同一年中 ,N、P、K、NPK施肥处理对木材管胞长、宽及基本密度的影响不同 ,同一施肥处理在不同年度中 ,对上述性质的影响亦异 ,总之 ,无明显变化规律。方差分析表明 4个施肥处理与无施肥处理的管胞长、宽及基本密度差异均不显著 ,生长轮宽度与管胞形态和基本密度都不显著相关。  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   

20.
对15年生火炬松半同胞家系的生长和材性性状测定表明:火炬松家系树高、胸径、材积、木材基本密度、纤维素含量、管胞长度与宽度等具有显著的差异;在家系水平上,木材基本密度、纤维素含量、管胞长度与宽度和材积生长相关不明显.遗传力测定表明:家系生长性状与材性性状平均遗传力均较高,达到中等程度以上.对树高生长、胸径生长、木材基本密度、纤维素含量、管胞长度与宽度等性状进行年度相关、早晚期选择研究表明:火炬松家系的生长相关主要由遗传决定;树高从第5年开始,胸径从第4年开始与以后各年的相关系效均在0.7以上,表明以此为最低年龄进行早期选择有较大的可靠性;木材基本密度10年生与其后各年龄级的相关系数值趋于稳定,术材密度最低选择年龄为10年;木材纤维素含量11年生与其后各年龄级的相关系效值趋于稳定,木材纤维素含量的最低选择年龄为11年.  相似文献   

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