Variability of selected wood characteristics in 40 half-sib families of black spruce (Picea mariana)

Summary Based on 15-year-old black spruce (Picea mariana) trees from 40 half-sib families sampled from 9 blocks of a family test in New Brunswick, this study examined intertree and intratree variation in various wood density and ring width characteristics. Of various variance components of the intertree variation, a remarkable variance component due to family was found in wood density characteristics (viz. average wood density, average earlywood density and latewood density of the tree), and these characteristics are thus under strong genetic control (h _i ² ranging from 0.60 to 0.86, and h _f ² from 0.56 to 0.68). It, to a lesser extent, applies to ring width characteristics at the tree level (viz. average ring width, and average earlywood width, latewood width and latewood percent of the tree) that show a lower heritability (h? from 0.18 to 0.28, and h _f ² from 0.22 to 0.36). Both block and block × family interaction contribute little to the total intertree variation encountered in 40 families from 9 blocks, while tree-to-tree variation within the family accounts for most (over 3/4) of the total intertree variation.Compared to the intertree variation (tree-to-tree variation within the family), the intratree variation in various wood characteristics studied is considerably larger in this species. It appears that most intraring wood density characteristics show a relatively smaller intertree variation but a relatively larger intratree variation as compared to ring width characteristics (except latewood width and latewood percent). Latewood width and latewood percent show the smallest intertree variation and the largest intratree variation. Between the two sources of the radial intratree variation, cambial age explains much more variation in most intraring wood density characteristics, while ring width accounts for more variation in earlywood width, latewood width and intraring density variation. This indicates that wood density of growth rings in this species is dependent more on cambial age than ring width (growth rate). Among various wood density and ring width characteristics studies, maximum (latewood) density shows the strongest response to calendar year. This characteristics is thus a useful dendroclimatic parameter in this species.I would like to thank Dr. E.K. Morgenstern and Mr. D. Simpson for their involvement in the planning of this study. Thanks are also due to G. Chauret, T. Keenam, R. Ploure, V. Steel and C. Reitlingshoefer for their technical assistance     

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.     

I-69杨年轮宽度和密度变异规律

以I-69杨木材为试样,运用树木年轮图像分析系统和树木年轮分析系统获取年轮宽度和年轮密度数据,并对组成成分径向变异和轴向变异规律进行了分析.结果表明:I-69杨木材密度的径向变异规律随树龄增加而增大,最大密度波动较大,最小密度随树龄增加总体趋势下降,早材密度、晚材密度随树龄增加而增加;年轮组成成分各项指标株内径向变异极...     

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.     

Influence of drought on tree rings and tracheid features of Pinus nigra and Pinus sylvestris in a mesic Mediterranean forest

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.     

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.     

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.

     

Dendrochronological investigation of wood extractives

X-ray microdensitometry was applied to a set of Scots pinewood (i.e. low extractive content). Earlywood and latewood properties were determined as minimum and maximum densities of each tree ring and the potential influence of acetone-soluble extractives (i.e. non-structural and secondary constituents of wood) was estimated using tree-ring statistics. The occurrence of extractives in different portions of wood was determined using dendrochronological methods, by comparing the densities of unextracted and extracted wood. It was not only found that unextracted samples exhibited inflated earlywood and latewood density values, but the growth trends were also altered. Extractives flattened the inter-annual growth variability, both in earlywood and latewood, and influenced the estimation of intra-annual radial growth variations. Characterizing the varying amount of extractives is of inter-disciplinary importance. The results in this study describe their occurrence and show that the radial variations in extractives could be highly detailed by simply using densitometry-based dendrochronology.     

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.     

Climatic signal from <Emphasis Type="Italic">Pinus leucodermis</Emphasis> axial resin ducts: a tree-ring time series approach

Developing long-term chronologies of tree-ring anatomical features to evaluate climatic relationships within species might serve as an annual proxy to explore and elucidate the climatic drivers affecting xylem differentiation. Pinus leucodermis response to climate was examined by analyzing vertical xylem resin ducts in wood growing at high elevation in the Apennines of peninsular Southern Italy. Early- and latewood tree-ring resin duct chronologies, spanning the 1804–2010 time period, were constructed. We analyzed the relationships between resin duct chronologies and climate over the last century using correlation and response function analyses. Overall, results showed that ring width and resin duct relationships differed between early- and latewood, which indicated conditions affecting growth were not associated with resin duct production. Results also revealed differential responses to climate between early- and latewood resin duct chronologies. A notable observation was a positive and stable relationship between latewood resin duct number chronology and July maximum temperature throughout the twentieth century. This result suggested resin ducts might be a suitable proxy to evaluate P. leucodermis response to climate in the study area.     

Climatic response of ring width and maximum latewood density of Larix sibirica in the Altay Mountains, reveals recent warming trends

? Introduction

Siberian larch (Larix sibirica) is a highly climate sensitive species. Presently, the Altay Mountains is covered by widespread forests dominated by Siberian larch and thus has a great potential for dendroclimatological studies. However, tree-ring network of the Altay Mountains has not yet been well developed. The development of the new chronologies and the knowledge about the influence of climatic variables on tree growth is needed.

? Method

X-ray densitometric techniques were applied to obtain ring width (RW) and maximum latewood density (MXD) of Siberian larch from two upper tree line sites in the Altay Mountains, China. Climatic responses in ring widths and maximum latewood densities from the Altay Mountains (China, Russia, and Mongolia) were investigated by simple correlation analyses. To assess the common growth forces among the individual sites of the Altay Mountains, simple correlation, principal component analyses, and spatial correlation analysis were applied over the common period of the chronologies.

? Results

Ring width and maximum latewood density increases with decreasing precipitation, increasing temperature from late spring to late summer during the growing season. Based on the results of principal component analyses and spatial correlation analysis, summer temperature (June?CJuly) is the most important forces on the Siberian larch growth of the Altay Mountains. The growth of Siberian larch in the Altay Mountains captures the current warming trend. The growth of Siberian larch did not clearly lose its sensitivity under most recent warming in our study areas.

? Conclusions

The new MXD chronologies is presently the longest, absolutely dated, tree-ring density record yet developed from China. The climate response analysis shows that the RW and MXD of Siberian larch have strong responses to temperature in the growing season. Thus, MXD and RW of Siberian larch provides the best information for climate reconstruction in the warm season. Tree-rings of Siberian larch allow detecting the recently observed warming trend and putting it into the long-term climatic context in the Altay Mountains, due to the strong growth sensitivity to temperature change.     

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     

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──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。     

广西柳州杉木种源树轮宽度对温度与湿度的年际响应

[目的]为选择适合试验区域未来气候变化条件下生长的杉木种源,[方法]运用年轮气候学方法,研究52个杉木地理种源3个树轮宽度指标对气候因子的响应。[结果]整轮宽度、早材宽度和晚材宽度与年平均气温的响应呈强负相关关系,相关系数最大值分别为-0.515、-0.590和-0.451;整轮宽度、早材宽度和晚材宽度与年最高气温均呈强负相关关系,相关系数最大值分别为-482、-0.624和-0.499。[结论]未来试点年平均气温有升高的趋势,这将会在一定程度上抑制杉木的径向生长,而选择对温度响应不太敏感的湖南江华、广西博白和广西资源种源在试验林所在区域进行造林,将是解决这一问题的有效途径。     

Comparison of growth response ofAbies andPicea species to climate in Mt. Norikura, Central Japan

Tree-ring chronologies were developed fromAbies mariesii Masters andPicea jezoensis ssp.hondoensis (Mayr) P. Schmidt collected at different altitudes of Mt. Norikura, central Japan. The tree-ring parameters of ring width and maximum density were measured by soft X-ray densitometry. The measurement series were detrended by fitting a 33-year cubic smoothing spline and autoregressive model. The correlation between species and between sites showed different responses of the species to climate in terms of ring width and maximum density. The correlation coefficient between sites within a species was higher than that between species for a site in the ring width, and the coefficient between species for a site was higher in maximum density. The correlation coefficient between tree-ring chronology and monthly climate data set showed different responses of radial growth to climate. The different response was probably explained by the difference in the length of the growing season. High summer temperature increased the maximum density of the two species and the radial growth inAbies mariesii. Summer precipitation correlated negatively to maximum density, but it did not affect the ring width of either species. The climatic signals could be extracted from ring-width and maximum-density chronologies of both species.     

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.     

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.     

Climatic significance of tree-ring width and intra-annual density fluctuations in Pinus pinea from a dry Mediterranean area in Portugal

In Mediterranean climates trees may go through two periods of dormancy, resulting in special anatomical features such as false rings and other intra-annual density fluctuations (IADFs). In this paper, ring growth and the presence of IADFs were studied in Pinus pinea L. growing in the coastal and inland regions of Alentejo (southern Portugal). In order to identify the triggering factors associated with the IADFs, a new classification was proposed for the IADFs in P. pinea: Type E (latewoodlike cells within earlywood); Type E+ (transition cells between earlywood and latewood); Type L (earlywoodlike cells within latewood) and Type L+ (earlywoodlike cells between latewood and earlywood of the next tree ring). Response function analyses showed that radial growth of P. pinea was strongly correlated with precipitation in southern Portugal. The climatic response of P. pinea was higher in the inland area where the summer drought is more severe, the winter temperatures are lower and the soils have low water-holding capacity, in comparison with the coastal area. IADFs were frequent in P. pinea and most of the IADFs were observed in latewood. The presence of IADFs was correlated with fluctuations in climate parameters during the growing season. The IADF type E+ was linked to precipitation events early in summer. The IADF type L and L+ were associated with above-average precipitation in early autumn.     

Climatic signal in annual growth variation of silver fir (Abies alba Mill.) and spruce (Picea abies Karst.) from the French Permanent Plot Network (RENECOFOR)

This paper explores the growth/climate relationships in earlywood, latewood and total ring-width chronologies of five Norway spruce (Picea abies) and six silver fir (Abies alba) stands sampled in the French permanent plot network (RENECOFOR) (327 trees). The relationships between climate and ring widths were analyzed using extreme growth years, simple correlations and response functions analysis (bootstrapped coefficients). Monthly climatic regressors were derived by a physiological water balance model that used daily climatic data and stand parameters to estimate soil water deficits. Pointer years underline the high sensitivity to winter frosts (1956, 1986) and exceptional annual droughts (1962, 1976, 1991) for both species. For those years, growth variations were higher for Abies alba than for Picea abies. For each species, the climate information of tree ring series is not modified by local site characteristics (altitude, slope, aspect, soil water reserve). Moreover, strong specific differences appear among species. Earlywood and latewood spruce growth mainly depends on current summer soil water deficit conditions. For silver fir, winter and early summer temperatures, as well as the water supply of the previous year (August to October) play a major role for the production of earlywood, after which the current early summer water supply influences mainly latewood width.