Effect of age on the variation, correlations and inheritance of selected wood characteristics in black spruce (Picea mariana)

Summary The variation, correlations and inheritance of various intraring wood characteristics in 15-year-old black spruce (Picea mariana) trees from 40 half-sib families grown in New Brunswick were examined. The emphasis was placed on the effect of age on these genetic parameters. With increasing (cambial) age, ring width and ring density tend to exhibit a constant tree-to-tree variation whereas most other characteristics exhibit a smaller tree-to-tree variation. The heritability for latewood characteristics does not seem to change appreciably. Other characteristics (except RDmi), however, tend to be less heritable when the tree grows older. Correlations between ring density and most intraring characteristics tend to be weaker with increasing age. This implies that fast-growth in this species will have less negative effect on wood density when the tree grows older.The author wishes to thank Dr. E.K. Morgenstern of the Genetic Resource Consultants, Permbroke, Ontario and Mr. D. Simpson of the Canadian Forest Service in Fredericton, New Brunswick for their involvement in the initial planning of this project. Thanks are also due to G. Chauret, T. Keenam, R. Ploure, V. Steel and C. Reitlingshoefer for their technical assistance.     

木材材性株内径向变异模式初探──Ⅲ.种植密度对湿地松、火炬松木材密度径向变异模式的影响

对两个地区不同种植密度的湿地松、火炬松进行了微密度分析，研究了种植密度对木材密度径向变异模式的影响。主要结果是：种植密度对湿地松和火炬松各密度特征值径向变异模式的影响，主要表现在变异曲线平均水平高低的变动，而对变异曲线形状的影响并不显著。种植密度对湿地松和火炬松各年轮宽特征值径向变异模式的影响，主要表现在年轮宽度RW和早材宽度EW变异曲线平均水平高低的变动和RW、EW与晚材宽度LW变异曲线形状的变动。种植密度对年轮密度RD的影响从年轮内宽度和年轮密度变异曲线平均水平高低两个方面起作用，出现较复杂的情况，并非所有情况下都是单调的正相关。     

Genetic control of intra-ring wood density variation in hybrid larch (Larix gmelinii var. japonica × L. kaempferi) F1

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.     

Genetic parameters for early wood and latewood densities and development with increasing age in Scots pine

? Each annual ring in pines consists of earlywood and latewood with considerable difference in density and width. To get a better determination of the genetic regulation of total wood density in Scots pine (Pinus sylvestris L.), density and width of those ring sections were measured in annual ring numbers 12 to 21 of Scots pines in a full-sib progeny test. Tree height and stem diameter were also measured.

? Heritabilities for the annual ring sections increased with age for earlywood density from 0.08 to approximately 0.25; latewood density showed similar reductions. Heritability over all 10 annual rings was 0.25 for earlywood density, 0.22 for latewood density, 0.29 for height and 0.10 for stem diameter. Genetic correlations between earlywood and latewood density and growth traits were negative, while they were strongly positive between densities of adjacent annual rings (0.70–1.0).

? Despite the higher heritability of earlywood density, the strong positive genetic correlation between those traits indicates little benefit from focusing solely on earlywood density when selecting for wood density. Analysing earlywood and latewood separately does not benefit from including the width of the corresponding ring section as a covariate. Juvenile wood may possibly turn into mature wood 15–20 y from the pith.

     

Ring characteristics and screw withdrawal resistance of naturally regenerated <Emphasis Type="Italic">Chamaecyparis obtusa</Emphasis> var. <Emphasis Type="Italic">formosana</Emphasis> trees

The ring characteristics and screw withdrawal resistance (SWR) of naturally regenerated Taiwan yellow cypress (Chamaecyparis obtusa var. formosana) trees were explored. Significant differences in average ring width (RW), earlywood width, latewood width, ring density (RD), earlywood density (ED), latewood density (LD), highest density (D_max), lowest density (D_min), latewood percentage (LWP), and SWR were observed between trees, rings (SWR excluded), and tree height positions. The RW components in the radial direction increased from the pith outward to about the 3rd to 5th ring and then decreased to about the 25th ring; it was almost constantly sustained toward the bark side. The RD in the radial direction slowly decreased from the pith outward to the bark side. Average ring width and ring density were significantly affected by the various tree growth rates, radial ring numbers, and tree height positions. ED, LD, D_max, D_min, and LWP were the most important factors determining the overall RD. RW did not correlate with tree RD. SWR is correlated with ED, RD, D_min, LWP, and intra-ring density variation (IDV). Thus, the SWR can be used to predict wood density and in nondestructive evaluation of a living tree.     

Effect of thinning on the ring characteristics of Japanese cedar plantation trees

The purpose of this study was to explore the ring characteristics of Japanese cedar (Cryptomeria japonica) tree growth with thinning and unthinning regimes. The trees grown with thinning regimes increased in average ring width (RW), earlywood width, latewood width, ring density (RD), earlywood density, latewood density, maximum ring density, and latewood percentage (LWP) for the entire period of 16 years after thinning, as compared to those grown with unthinning regimes. The RW and RD components showed different reactions lasting several years after thinning. Overall, thinning caused immediate production (first year) of higher RD, lasting for several years; however, wider RW was delayed up to several years after treatment. There was a weak relationship between RW (growth rate) and wood density; and there were significant positive relationships between the RD and LWP. The results suggest that the compression wood produced after thinning.     

Relationships among selected wood properties of 20-year-old Taiwania (<Emphasis Type="Italic">Taiwania cryptomerioides</Emphasis>) trees

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.     

Variations and correlations of various ring width and ring density features in European oak: implications in dendroclimatology

Summary Variations and correlations of various ring width and ring density features were analyzed in 18 European oak (Quercus petraea andQuercus robur) trees from northeastern France. In light of these analyses, the goodness of various tree-ring features as a climatic parameter was discussed. In general, ring density features (viz. earlywood density, latewood density, average ring density, minimum density and maximum density) show a stronger response to calendar year, a comprehensive climatic variable, than ring width features (viz. earlywood width, latewood width, total ring width and latewood percent). The response of latewood features (viz. latewood width, latewood density and maximum latewood density) is stronger than that of earlywood features (viz. earlywood width, earlywood density and minimum earlywood density). Average ring density seems to be the most sensible tree-ring feature in European oak in terms of the response to calendar year. Moreover, total ring width as a climatic parameter is not as good as latewood width, and maximum (latewood) density and minimum (earlywood) density appears not to contain as much climatic information as (average) latewood density and (average) earlywood density, respectively.This project was supported by the institut National de la Recherche Agromonique (INRA). Thanks are due to Dr. G. Nepveu for his constant encouragement and assistance during this study     

Radial variation of wood density components and ring width in cork oak trees

The radial variation of ring width and wood density was studied in cork oaks (Quercus suber) using microdensitometry. The observations were made in young never debarked cork oaks (30–40 years of age) and in mature trees under cork production (37–60 years of age). The cork oak wood is very dense (mean ring density 0.86 g.cm^?3, between 0.79 g.cm^?3 and 0.97 g.cm^?3) with a small intra-ring variability (mean earlywood density 0.80 g.cm^?3 and latewood density 0.90 g.cm^?3). The density components decreased from pith to bark more rapidly until the 15th ring, and then only slightly. There were no significant differences in the mean density components between never debarked trees and trees under cork production but their outwards decrease was accentuated in the never debarked trees. The annual growth was high, with a ring width mean of 3.9 mm (4.2 mm in the first 30 years) and the latewood represented 57% of the annual growth.     

Variation in wood density and ring width in Acacia melanoxylon at four sites in Portugal

The radial variation in wood density in Acacia melanoxylon R. Br. was studied using microdensitometry by sampling 20 trees with a 40-cm diameter class at four sites in Portugal. The measurements were taken from pith to bark at breast height. A. melanoxylon had an average ring density of 0.607 g cm^?3, ranging from 0.556 to 0.630 g cm^?3. The mean growth was 6.0 mm year^?1. Latewood corresponded, on average, to 34 % of the ring width. Between-tree variability at each site was the main source of variation in the density components, representing between 30 and 54 % of the total variation. Between-sites variability represented from 0 to 21 % of the total variation in density components. The environmental effects (site related) were more pronounced on latewood, while the genetic effect (tree related) was more evident in earlywood. Ring width, latewood percentage and heterogeneity index were independent from site, trees in site and age effects. The values of wood density and radial growth revealed that A. melanoxylon can be important as a commercial timber species in Portugal.     

木材材性株内径向变异模式初探VI19个杉木种源木材密度径向变异模式的研究

以微密度分析对19个种源杉木的木材密度径向变异模式进行了研究.不同种源间和种源内株间,年轮平均密度的径向变异曲线都存在一定的变异,但此变异主要表现在种源内株间.年轮平均密度的幼龄-成熟相关性从第3年起就极显著.由微密度分析得出的一系列密度和年轮宽特征值间的相关分析表明,在年龄影响下的变异过程中,年轮内密度变异曲线随年轮宽的变动导致晚材率变动的效应较为显著,年轮平均密度主要受晚材率影响;年轮平均密度与年轮宽呈特别显著的负相关.而在种源影响下的变异过程中分析,上述效应不明显,而不同种源间密度变异曲线的上下移动影响显著;年轮平均密度主要受早材平均密度影响;年轮平均密度与年轮宽的负相关远不如在年龄影响下的变异过程中显著.     

日本落叶松无性系木材性质的遗传变异

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.     

Genetic correlations between wood quality traits of <Emphasis Type="Italic">Pinus pinaster</Emphasis> Ait

• ? It is essential to understand how characteristics are related to each other in breeding programmes to select wood properties, in order to avoid that, in selecting for one trait, we are negatively affecting another. Moreover, measuring wood properties is time consuming and expensive.
• ? This study assesses genetic and phenotypic correlations between wood density components and spiral grain of 46 half-sib families of Pinus pinaster in seventeen-year-old trees.
• ? Results showed that genetic correlations for all wood density components were higher than corresponding phenotypic correlations. Furthermore, all wood density components were highly genetically correlated with ring density, and also closely associated among themselves. Results showed a higher genetic correlation of ring density with earlywood density (r _g = 0.96) than with latewood density r _g = 0.79). A moderate to high positive genetic correlation was found between spiral grain and wood density characteristics (0.29–0.61).
• ? We conclude that ring density (overall wood density) can be improved by increasing either earlywood density, latewood percent, or both of these traits, and spiral grain can be modify in future plantations.

     

The effects of within-species and between-species variation in wood density on the photodegradation depth profiles of sugi (Cryptomeria japonica) and hinoki (Chamaecyparis obtusa)

Low density wood is more rapidly eroded than denser wood when exposed to the weather, possibly because it is more susceptible to photodegradation. Fourier transform infrared microscopy was used to examine: (1) the depth of photodegradation in earlywood and latewood of sugi (Japanese cedar) and earlywood of hinoki (Japanese cypress) exposed for up to 1500 h to artificial sunlight emitted by a xenon lamp (375 W/m² within the 300 to 700 nm spectral range); and (2) the relationship between the density of wood tissues and depth of photodegradation. The depth of photodegradation varied between species (sugi and hinoki) as well as within a growth ring (sugi earlywood and latewood), and there was an inversely proportional relationship between depth of photodegradation and wood density. These findings may explain why low density earlywood is more rapidly eroded than latewood during weathering, and more generally, why there is an inverse relationship between the density of wood species and their rate of erosion during artificial and natural weathering. Part of this work was presented at the 54th Annual Meeting of the Japan Wood Research Society, Sapporo, August 2004     

Intra-increment variation in specific gravity of wood in blue pine

Summary Intra-increment variation in specific gravity of wood is studied in relation to the types of annual increments in Pinus wallichiana. In the normal annual increments specific gravity increases almost linearly across the ring, displaying minimum value in the first-formed earlywood and maximum value in the last-formed latewood. The occurrence of false rings and that of compression wood in an annual ring causes a localized increase in specific gravity. The change in specific gravity at the false growth ring boundary is slight and gradual, whereas at the true annual rings boundary the change is steep and abrupt. The specific gravity in the first-formed earlywood portion gives the most consistent value as compared to whole earlywood, whole latewood and whole ring when studied around the circumference.The financial support from University Grants Commission (India) is gratefully acknowledged     

Inter-tree and intra-tree variations in ring width and wood density components in balsam fir (Abies balsamea)

This study quantified and compared intra-tree and inter-tree variations in ring width and wood density components in balsam fir (Abies balsamea) grown in Quebec, Canada. In addition, the study examined correlations between ring width and wood density components at different stem positions from the stump level to the stem top. Ring width and wood density components of individual rings were measured by X-ray densitometry. Both the intra- and inter-tree variations in balsam fir are large, but the inter-tree variation is relatively smaller than the intra-tree variation. Much of the intra-tree variation is due to the radial variation, whereas the axial variation is much smaller. Compared to ring width and its components, wood density characteristics show a considerably smaller variation at both the inter- and intra-tree level. In almost all wood characteristics studied (except for latewood width), the intra- and inter-tree variations are more or less influenced by tree age. Cambial age explains more intra-tree variation in wood density components than ring width, whereas more intra-tree variation in ring width components is due to ring width. Cambial age and ring width explain a comparable percentage of variation in ring density. Only a few of the correlations between ring width and wood density components vary significantly with stem position from the stump to the stem top at the inter-tree level. In balsam fir, a negative correlation between ring density and ring width is significant in the butt log, but the correlation decreases to an insignificant level at and above a height of 3.0 m.     

Statics and kinetics of water vapor sorption of small loblolly pine samples

A better understanding of the sorption behavior of different wood structures could be useful in protecting wood against wood deterioration and fungal attack. The purpose of this study was to investigate the effect of differences among earlywood, latewood, and tree ring location within the stem cross-section of loblolly pine (Pinus taeda) on the sorption kinetics and statics of water vapor under ambient conditions. The water vapor sorption of earlywood and latewood in different tree rings was recorded using a dynamic contact angle analyzer under relative humidity changes from 11 to 89%, as provided by saturated salt solutions. Earlywood had higher sorption rates and diffusion coefficients than latewood, while outer tree rings had higher sorption rates and diffusion coefficients than inner tree rings. The sorption isotherms of earlywood, latewood, and different tree ring locations within the stem cross-section were fitted very well by a Hailwood–Horrobin model.     

Elevated temperature and CO(2) concentration effects on xylem anatomy of Scots pine

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.     

Effect of growth on wood properties for Japanese larch (Larix kaempferi): Differences of annual ring structure between corewood and outerwood

To investigate the relations between growth and the wood properties of Japanese larch (Larix kaempferi), six sample trees of varied ages and radial growth were felled and the ring width, ring density, percentage of latewood, and some other factors were determined. There were significant differences in ring density and percentage of latewood between sample trees with vigorous growth and those with poor growth. In corewood the ring density decreased with increasing ring width for all sample trees, whereas in outerwood this trend did not appear. Moreover, the latewood width increased with the increment of ring width only in outerwood, whereas there was almost no change in the corewood. The variation in patterns of ring width, ring density, and percentage of latewood in the radial direction and the relation with height was also studied.Part of this report was presented at the 47th annual meeting of the Japan Wood Research Society, Kochi, April 1997