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1.
Hydraulic and mechanical properties of young Norway spruce clones related to growth and wood structure 总被引：3，自引：0，他引：3
Stem segments of eight five-year-old Norway spruce (Picea abies (L.) Karst.) clones differing in growth characteristics were tested for maximum specific hydraulic conductivity (k(s100)), vulnerability to cavitation and behavior under mechanical stress. The vulnerability of the clones to cavitation was assessed by measuring the applied air pressure required to cause 12 and 50% loss of conductivity (Psi(12), Psi(50)) and the percent loss of conductivity at 4 MPa applied air pressure (PLC(4MPa)). The bending strength and stiffness and the axial compression strength and stiffness of the same stem segments were measured to characterize wood mechanical properties. Growth ring width, wood density, latewood percentage, lumen diameter, cell wall thickness, tracheid length and pit dimensions of earlywood cells, spiral grain and microfibril angles were examined to identify structure-function relationships. High k(s100) was strongly and positively related to spiral grain angle, which corresponded positively to tracheid length and pit dimensions. Spiral grain may reduce flow resistance of the bordered pits of the first earlywood tracheids, which are characterized by rounded tips and an equal distribution of pits along the entire length. Wood density was unrelated to hydraulic vulnerability parameters. Traits associated with higher hydraulic vulnerability were long tracheids, high latewood percentage and thick earlywood cell walls. The positive relationship between earlywood cell wall thickness and vulnerability to cavitation suggest that air seeding through the margo of bordered pits may occur in earlywood. There was a positive phenotypic and genotypic relationship between k(s100) and PLC(4MPa), and both parameters were positively related to tree growth rate. Variability in mechanical properties depended mostly on wood density, but also on the amount of compression wood. Accordingly, hydraulic conductivity and mechanical strength or stiffness showed no tradeoff. 相似文献
2.
人工兴安落叶松次生木质部的解剖学研究 总被引：1，自引：0，他引：1
运用木材解剖图像分析系统和显微照相的方法对人工兴安落叶松次生木质部的解剖结构进行研究,结果表明:落叶松具正常树脂道和受伤树脂道两种类型,前者常见于晚材。落叶松生长轮内的早晚材在干和枝内急变,在根内缓变。早材管胞呈六边形至多边形,胞壁常见单列具缘纹孔,偶见对列具缘纹孔;晚材管胞多呈矩形,胞壁鲜见具缘纹孔,通常为单列具缘纹孔。落叶松木射线同时具有单列木射线和纺锤形木射线两种类型,纺锤形木射线中仅含一枚纵行树脂道。纵行管胞与木射线交叉形成的纹孔场为云杉型。从根到干再到枝,管胞逐渐细化,管胞长度逐渐减小,木射线分布由密到疏。 相似文献
3.
Kilpeläinen A Gerendiain AZ Luostarinen K Peltola H Kellomäki S 《Tree physiology》2007,27(9):1329-1338
We studied the effects of elevated temperature and carbon dioxide concentration ([CO(2)]) alone and together on wood anatomy of 20-year-old Scots pine (Pinus sylvestris L.) trees. The study was conducted in 16 closed chambers, providing a factorial combination of two temperature regimes and two CO(2) concentrations (ambient and elevated), with four trees in each treatment. The climate scenario included a doubling of [CO(2)] and a corresponding increase of 2-6 degrees C in temperature at the site depending on the season. Anatomical characteristics analyzed were annual earlywood, latewood and ring widths, intra-ring wood densities (earlywood, latewood and mean wood density), tracheid width, length, wall thickness, lumen diameter, wall thickness:lumen diameter ratio and mass per unit length (coarseness), and numbers of rays, resin canals and tracheids per xylem cross-sectional area. Elevated [CO(2)] increased ring width in four of six treatment years; earlywood width increased in the first two years and latewood width in the third year. Tracheid walls in both the earlywood and latewood tended to become thicker over the 6-year treatment period when temperature or [CO(2)] was elevated alone, whereas in the combined treatment they tended to become thinner relative to the tracheids of trees grown under ambient conditions. Latewood tracheid lumen diameters were larger in all the treatments relative to ambient conditions over the 6-year period, whereas lumen diameters in earlywood increased only in response to elevated [CO(2)] and were 3-6% smaller in the treatments with elevated temperature than in ambient conditions. Tracheid width, length and coarseness were greater in trees grown in elevated than in ambient temperature. The number of resin canals per mm(2) decreased in the elevated [CO(2)] treatment and increased in the elevated temperature treatments relative to ambient conditions. The treatments decreased the number of rays and tracheids per mm(2) of cross-sectional area, the greatest decrease occurring in the elevated [CO(2)] treatment. It seemed that xylem anatomy was affected more by elevated temperature than by elevated [CO(2)] and that the effects of temperature were confined to the earlywood. 相似文献
4.
对10个10年生日本落叶松无性系的木材基本密度、管胞参数进行了测定.结果表明:木材基本密度,早、晚材管胞宽度和早材长宽比无性系间差异显著;木材基本密度,早、晚材管胞长度,早晚材管胞宽度和早晚材长宽比径向变异模式相似,即从髓心向外以曲线形式不断增加,有时亦有起伏;早材从髓心向外以近似直线的形式缓慢增加,晚材从髓心向外以曲线形式增加,初期增加幅度较大,到一定年龄后趋于水平变化并略有波动;材质性状与树木年轮间的关系以对数方程、幂函数方程、指数方程拟合效果较好;除了晚材壁腔比和早材壁厚外,其它木材性质的重复力均在0.5以上,受中度或中度以上的遗传制约,按照20%的选择率,长宽比和晚材管胞长能获得较高的遗传增益. 相似文献
5.
Cornelia Krause Sergio Rossi Maxime Thibeault-Martel Pierre -Y. Plourde 《Annals of Forest Science》2010,67(4):402-402
6.
《Scandinavian Journal of Forest Research》2012,27(1):14-29
Genetic parameters were estimated for wood and growth traits in two 19-yr-old clonal trials and a 40-yr-old full-sib progeny trial of Norway spruce [Picea abies (L.) Karst.]. In the clonal trials high (>0.4) broad-sense heritabilities were found for wood density traits, lignin content, number of internal cracks, growth traits, spiral grain and number of resin canals. Moderate (0.2–0.4) heritabilities were found for tracheid lumen diameter and cell wall thickness, microfibril angle and tracheid length, while low heritabilities (<0.2) were found for pulp yield, fibre strength, wood stiffness and wood colour. Lignin content and pulp yield showed low genetic variation, whereas the genotypic coefficient of variation for most other traits ranged between 5 and 15%. Most traits showed low levels of genotype by environment interaction. Among the wood properties, latewood proportion, earlywood density and ring density showed significant, adverse correlations with volume in both clonal trials. 相似文献
7.
Dario Martin-Benito Hans Beeckman Isabel Cañellas 《European Journal of Forest Research》2013,132(1):33-45
We investigated the influence of climate on the ring width and xylem anatomy of two co-occurring pines (Pinus nigra Arn. and P. sylvestris L.) in the mountains of east-central Spain in order to test their utility for dendroclimatic reconstructions. We developed chronologies of ring width, mean lumen diameter and mean cell-wall thickness (in the earlywood, latewood, and the total annual ring) and the number of cells between 1960 and 2006. Drought, expressed as the standardized precipitation-evapotranspiration index (SPEI), was the main climatic driver of tree radial growth, although trees were also sensitive to temperature (negative effect in previous autumn and current summer) and precipitation (with a general positive effect). P. sylvestris response was stronger to climate of the current year, whereas the effect of previous-year climate was more important for P. nigra. Warm and dry summers reduced ring width, tracheid lumen, and wall thickness in both species, whereas warm winter-spring temperatures had the opposite effect, primarily for P. sylvestris. Previous-year or early-season conditions mainly affected earlywood features, whereas latewood was more responsive to summer climate. Overall, climate appeared to be a stronger limiting factor for P. sylvestris. During periods of drought, cell-wall thickness was reduced while lumen width increased in the latewood of P. sylvestris. This could compromise its hydraulic safety against drought-induced cavitation as our site was close to the southern and dry edge of the species distribution area. Our results suggest that anatomical variables record different and stronger climate information than ring width variables, especially in P. sylvestris. Reconstruction models for SPEI at the 3-month scale were developed for July–August and September–October using principal components regression. The best models included anatomical and width variables of both pine species suggesting that tracheid chronologies can be useful for drought reconstructions especially at mesic sites or with species that encode a mixed drought and temperature-precipitation signal. 相似文献
8.
《Scandinavian Journal of Forest Research》2012,27(5):462-469
Abstract Wood properties, including tracheid cross-sectional dimensions, show a large degree of variation. To improve the properties of products made from wood, different methods to control variation have been developed. This study aims to determine the theoretical efficiency of three control strategies: the fractionation of pulped tracheids into earlywood and latewood, the separation of juvenile and mature wood, and sorting of logs according to tree size. The efficiency of each method was studied by first constructing virtual trees from measured tracheid cross-sectional dimensions, then simulating the efficiency of above-mentioned methods. The tracheid dimension data include Norway spruce (Picea abies (L.) Karst.) and Scots pine (Pinus sylvestris L.). The simulations show that separation into earlywood and latewood classes has the highest theoretical efficiency and yields the lowest variances in raw material. Classification into juvenile and mature wood groups is the second most efficient method, and the sorting of logs according to the size class of the tree is the least efficient method. It was also concluded that the variation in cell-wall thickness and radial diameter mainly originates from differences between earlywood and latewood, whereas the variation in tangential diameter mainly originates from differences between mature and juvenile wood. 相似文献
9.
The relationships between bending properties, compressive strength, tracheid length, microfibril angle, and ring characteristics
of 20-year-old Taiwania (Taiwania cryptomerioides Hay.) trees were examined. The trees came from different thinning and pruning treatments, but the practices showed no significant
effect on the investigated properties. The results showed that based on comparison with the literature, plantation-grown immature
Taiwania have noticeably lower average strength properties than mature trees of the same species. Wood density and bending
and compressive strengths were not related to either tracheid length or microfibril angle in young Taiwania. There were positive
relationships between bending strength and compressive strength. The wood density, ring width, earlywood width, earlywood
density, and latewood percentage were the most important predictors of strength by simple linear regressions. The wood density
and ring width/earlywood width may be considered as indicators for assessing the bending strength, while wood density and
latewood percentage were the best predictors of compressive strength by multiple linear regressions. 相似文献
10.
We tested the hypotheses that freezing-induced embolism is related to conduit diameter, and that conifers and angiosperms with conduits of equivalent diameter will exhibit similar losses of hydraulic conductivity in response to freezing. We surveyed the freeze-thaw response of conifers with a broad range of tracheid diameters by subjecting wood segments (root, stem and trunk wood) to a freeze-thaw cycle at -0.5 MPa in a centrifuge. Embolism increased as mean tracheid diameter exceeded 30 microm. Tracheids with a critical diameter greater than 43 microm were calculated to embolize in response to freezing and thawing at a xylem pressure of -0.5 MPa. To confirm that freezing-induced embolism is a function of conduit air content, we air-saturated stems of Abies lasiocarpa (Hook.) Nutt. (mean conduit diameter 13.7 +/- 0.7 microm) by pressurizing them 1 to 60 times above atmospheric pressure, prior to freezing and thawing. The air saturation method simulated the effect of increased tracheid size because the degree of super-saturation is proportional to a tracheid volume holding an equivalent amount of dissolved air at ambient pressure. Embolism increased when the dissolved air content was equivalent to a mean tracheid diameter of 30 microm at ambient air pressure. Our centrifuge and air-saturation data show that conifers are as vulnerable to freeze-thaw embolism as angiosperms with equal conduit diameter. We suggest that the hydraulic conductivity of conifer wood is maximized by increasing tracheid diameters in locations where freezing is rare. Conversely, the narrowing of tracheid diameters protects against freezing-induced embolism in cold climates. 相似文献
11.
12.
Summary The effects of air-drying and solvent-drying on the sapwood of Abies grandis have been investigated by a new method for the determination of the size and number of conducting tracheid lumina and pit membrane pores which involves the measurement of gaseous permeability at various mean pressures. Both earlywood and latewood tracheids (83% of the total) were found to be conducting in solvent-dried wood, but in air-dried wood only latewood tracheids (32% of the total) were conducting. In solvent-dried wood there were on average 27,000 pit membrane pores per conducting tracheid compared with only 600 in air-dried wood. In both, the average pit membrane pore radius was about 0.1 m.Liquid permeabilities have been predicted from the calculated radii and numbers. The liquid permeability of solvent-dried wood was 31 times greater than that of air-dried wood in which the lumina were responsible for 13% of the total resistance to flow. The lumina were responsible for 39% of the resistance in solvent-dried wood and it is suggested that in first-formed earlywood the lumina may cause more than half the total resistance.A new method is described for the cleaning of direct carbon replicas of wood. In this the cellulose is removed by cellulase instead of sulphuric acid, and no wax backing is required. This provides much cleaner replicas. Electron micrographs have been obtained of both earlywood and latewood dried by the two methods.The authors wish to thank Mr. A. R. Sayers for preparing the computer programme used in this work, Dr. R. Ph. C. Johnson for his help and advice regarding the electron microscopy and Professors Matthews and Weatherley for their advice and encouragement. 相似文献
13.
Genetic parameters for various wood density traits were estimated in 29-year-old trees of 18 full-sib families of hybrid larch
(Larix gmelinii var. japonica × Larix kaempferi) F1. Intra-ring density variation (IDV) was also evaluated using a model that expresses the pattern curve from earlywood to latewood
as a power function. A high IDV indicates an abrupt change in wood density from earlywood to latewood. The ring width and
wood density traits of individual rings were determined by X-ray densitometry. Overall wood density (RD) was shown to increase
with increasing ring number, ranging from 0.42–0.59 g/cm3, whereas IDV of individual rings decreased gradually from pith outwards. Estimates of individual tree narrow-sense heritability
of RD and IDV were 0.66 and 0.67, respectively. IDV showed negative genetic and phenotypic correlations with RD (r
g = −0.99, r
p = −0.72). The predicted genetic gains in latewood proportion and IDV were higher than that of RD. These results suggest that
the intra-ring density variation is under moderate genetic control equivalent to wood density. The trend of increasing wood
density from earlywood to latewood was associated with changes in both tracheid diameter and cell wall thickness. 相似文献
14.
Selected wood and cell characteristics were examined in incrementcores from two 46-year-old pines that had been fertilized withammonium sulphate 37, 38 and 39 years after planting. Fertilizationincreased the ring-width and greatly reduced the latewood percentand the bulk density of both early and late wood; the effectswere greatest shortly after the last application of fertilizer,but remained apparent for at least five further years. Thoughboth trees produced more early wood cells only one of the twoproduced more latewood. The average tracheid diameter was not changed, though its rangewithin the annual ring was increased. There were decreases intracheid wall-thickness and length, and in wall volume per tracheid.These changes were greatest in latewood, so that the differencebetween early and latewood was reduced, while the characteristicsof the earlywood were exaggerated. Resin canal radial (but nottangential) diameter and cross-sectional area increased, thoughnumber of canals per unit area of ring was unchanged. Correlations with temperature, insolation and rainfall in March-Juneand July-October suggest that (1) wood properties are influencedby the weather of both the current and the previous growingseasons; (2) the climatic optima for the fertilized and unfertilizedtrees are different and consequently (3) the weather influencesthe effect of fertilization on wood properties. 相似文献
15.
Roman Gebauer Roman Plichta Emilie Bednářová Jiří Foit Václav Čermák Josef Urban 《European Journal of Forest Research》2018,137(1):57-67
While needles represent a proportionally large fraction of whole-plant hydraulic resistance, no studies to date have investigated how source–sink disturbances affect needle xylem structure. In this study, we evaluated structural changes in xylem in current-year needles of Scots pine 227 and 411 days after stem girdling (hereafter referred to as DAG). Maximum and minimum tracheid lumen diameters and therefore also the size of tracheid lumen areas increased in needles 227 DAG compared to control needles. In contrast, tracheid dimensions were similar in needles 411 DAG as in the control needles, but smaller xylem area and lower number of tracheids resulted in the lower theoretical needle hydraulic conductivity of those needles. Several needle xylem parameters were intercorrelated in both control and girdled trees. These observed changes provide a new understanding of the processes that occur following a source–sink disturbance. Considering anatomical parameters such as the number of tracheids, tracheid dimension, or needle xylem area, which are rarely described in physiological studies, could be helpful, for example, in understanding to tree hydraulic systems or for modeling gas exchange. Finally, empirical equations were developed to calculate needle theoretical hydraulic conductivity and the number of tracheids in needles using an easily measurable parameter of needle xylem area. 相似文献
16.
17.
Variation of measured cross-sectional cell dimensions and calculated water vapor permeability across a single growth ring of spruce wood 总被引：1，自引：1，他引：0
A statistical study of the cell dimensions in a growth ring of spruce along the radial and tangential directions is performed. The data are used to study the variation of the cell vapor permeability in the growth ring. Studying cell rows within one growth ring, the frequency distributions of the cell wall thickness in the radial direction and of the lumen dimension in the tangential direction are found to be both unimodal. In contrast, the frequency distributions of these dimensions in the other directions are bimodal, where the different modes can be attributed to earlywood and latewood. Analysis of the bimodal distributions results in the determination of threshold values of cell wall thickness and the lumen dimension for earlywood and latewood tracheids. The cell dimensions are used to predict cell porosity and water vapor permeability distribution within a growth ring. The bimodal frequency distributions of the tangential cell wall thickness and the radial lumen dimension provide an explanation for the observed bimodal frequency distribution of the cell water vapor permeability both in radial and in tangential directions. Contrary to measured macroscopic vapor permeability results, the tracheid geometry results in lower cell vapor permeability in radial than in tangential direction. This confirms that rays play an important role in the vapor permeability of wood, as they can be considered as pathways for vapor transport in radial direction. The dataset analyzed in this paper leads to a set of parameters characterizing the earlywood and latewood cell dimensions. Such characterization can be used, for example, for producing synthetic data for computational modeling studies. 相似文献
18.
In this study, the contact angles of four different reference liquids (including distilled water, diiodomethane, formadide
and glycerol) formed on the surfaces of wood, treated with chromated copper arsenate (CCA) and two other emerging copper-based
water-borne systems (commercial names: NW and NS) were measured with sessile drop method. Based on the contact angle data,
the surface energy was obtained from the acid-base approach. The total surface energy consisted of Lifshiz-van der Waals parameter
and acid-base parameter. Results showed that the NW and CCA treatments made the wood surface more hydrophobic while the NS
treatment had the reverse effect on the wood surface mainly owing to the increased penetration of earlywood. By using three
liquids, diiodomethane, formamide and distilled water, the total surface energy obtained for untreated earlywood, untreated
latewood, CCA-treated earlywood, CCA-treated latewood, NW-treated earlywood, NW-treated latewood, NS-treated earlywood and
NS-treated latewood were 43.1, 44.5, 43.4, 45.1, 49.4, 40.6, 46.0 and 40.9 mJ/m2, respectively. The surface energy of CCA-treated wood was almost the same as untreated wood. After NW and NS treatments,
the surface energy of both earlywood and latewood changed a little. However, the change was not so obvious as to draw any
further conclusion concerning the influence of NW and NS treatments on the surface energy of wood.
__________
Translated from Journal of Beijing Forestry University, 2006, 28(4): 1–4 [译自: 北京林业大学学报] 相似文献
19.
In order to study the transverse swelling/shrinkage of wood, the microscopic swelling behavior of latewood tracheid was observed
using confocal laser scanning microscopy and the digital image correlation method. A microcrater structure was created on
the surface of the specimen by using the ion sputter etching technique to obtain a pattern-rich digital image for image analysis.
Douglas fir specimens were conditioned by two methods of absorption: rapid absorption of moisture from hot steam, and slow
absorption of moisture from the water vapor of saturated solutions. Latewood tracheid near the surface of the specimen deformed
only in the radial direction when the relative humidity of the surrounding air changed rapidly (rapid absorption of moisture
from hot steam or absorption/desorption of moisture during the observation). In addition, the diameter of the lumen decreased
upon rapid absorption of moisture, whereas it expanded upon slow absorption of moisture. These results indicate that the microscopic
swelling behavior of latewood cells is strongly influenced by the macroscopic/mesoscopic structure, for instance, the cell
arrangement or the alternation of latewood and earlywood.
Part of this report was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004 相似文献
20.
Nakai Takashi 《中国林业科技(英文版)》2003,(2)
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