Cambial Age Research Articles

Predicting selected wood properties of jack pine following commercial thinning

This paper examined the impact of commercial thinning on selected wood properties of jack pine ( Pinus banksiana Lamb.). Wood properties evaluated include wood density (ring density, earlywood ring density, and latewood ring density), percentage of latewood in the ring, and wood bending properties. Nonlinear, mixed-effect models have been developed using data from three commercially thinned sites in eastern Canada. Ring density followed the same pattern as percentage of latewood, in which cambial age, relative height, and ring width were found to have important effects. Earlywood and latewood ring densities changed within the juvenile wood zone until a plateau was reached. Ring width affected earlywood and latewood ring densities mainly in narrow rings. Wood bending stiffness (measured by modulus of elasticity) and strength (measured by modulus of rupture) increased with cambial age and wood density; whereas, wood strength was also affected by ring width. Commercial thinning did not influence the developed models, but it had an indirect effect through increased ring width.

Prediction ofPinus sylvestrisclear-wood properties using NIR spectroscopy and biorthogonal partial least squares regression

Thirteen wood parameters were predicted using near infrared (NIR) spectra in the range 780–2380 nm modelled by biorthogonal partial least squares regression. The analysis of parameters and NIR measurements was done on clear-wood samples from the base and midstem of Scots pine ( Pinus sylvestris L.) from trees at two sites. Calibrations based on the measured parameters at seven growth rings (cambial age ranging between 6 and 42 years) could be divided into three groups: (i) the best accuracy was found for longitudinal modulus of elasticity (r > 0.9) followed by bending, compression, and cell length (0.8 < r < 0.9); (ii) microfibril angle, longitudinal hardness, proportion of latewood, and creep with correlations in the range of 0.7–0.8; and (iii) tangential hardness, cell diameter, and cell wall thickness with 0.4 < r < 0.7. It was also shown that juvenile (cambial age ≤20 years) and mature wood can be classified using NIR techniques.

Age trends in genetic parameters of wood density components in 46 half-sibling families of Pinus pinaster

This study contributes to the Pinus pinaster Ait. breeding programme, which is reaching the third generation by adding information on wood quality of 46 open-pollinated families from a progeny trial located in Leiria, Portugal, that originated from seed collected in a clonal seed orchard. A total of 552 seventeen-year-old trees were sampled at 2 m height. Trends were studied from the pith outward in variance components and narrow-sense heritability (h2) of wood density components and ring-width characteristics as well as genetic correlations between cambial ages. Mean ring density (RD), minimum density (MND), maximum density (MXD), earlywood density (EWD), latewood density (LWD), earlywood width, latewood width, ring width, latewood percentage, and heterogeneity index were determined using X-ray densitometry procedures. RD had higher genetic control (h2 = 0.63), and heritability values of earlywood components (h2MND = 0.54, h2EWD = 0.60) exceeded those of latewood components (h2MXD = 0.34, h2LWD = 0.26). Heritabilities increased with ring number from pith for almost all wood density components, and there were high age–age genetic correlations for wood density traits (rg > 0.98).

The elemental composition, the microfibril angle distribution and the shape of the cell cross-section in Norway spruce xylem

Relationships between the elemental composition, the microfibril angle (MFA) distribution and the average shape of the cell cross-section of irrigated-fertilised and untreated Norway spruce (Picea abies [L.] Karst.) earlywood were studied. Sample material was obtained from Flakaliden, Sweden. The elemental composition was studied by determining the relative mass fractions of the elements P, S, Cl, K, Ca and Mn by X-ray fluorescence and by determining the mass absorption coefficients for X-rays. X-ray diffraction was used to determine the MFA distribution and the average shape of the cell cross-section. The latter was also determined by light microscopy. In transition from juvenile wood to mature wood, a decrease of the mode of the MFA distribution from 13°–24° to 3°–6° was connected to a change in the shape of the cell cross-section from circular to rectangular. The irrigation-fertilisation treatment caused no change in the MFA distribution or in the shape of the cell cross-section, whereas the mass absorption coefficient was higher and the density was smaller in irrigated-fertilised wood. Larger proportion of the elements S, Cl and K, but smaller proportion of the element Mn, were observed due to the treatment. The results indicate that the shape of the cell cross-section or the MFA distribution are not directly linked to the growth rate of tracheids or to the nutrient-element content in the xylem and only show notable changes as a function of the cambial age.

Do tree ring δ13C series from Pinus sylvestris in northern Fennoscandia contain long-term non-climatic trends?

Non-climatic trends in tree ring δ 13C series are investigated using highly replicated Pinus sylvestris δ 13C series from Finnish Lapland. The declining trend in stable carbon isotopes over the industrial period, reflecting changes in the isotopic ratio of atmospheric CO 2 is removed mathematically, without recourse to statistical de-trending. Regional Curve Standardisation (RCS) is then used to identify and remove the juvenile phase during which δ 13C values increase. The chronologies all show approximately 1‰ depletion in the juvenile phase, with an average rise of 0.029‰ year − 1 lasting for about 50 years, after which trees of very different cambial age capture common variance over the same chronological period. There is no evidence of long-term age-related trends and RCS provides an alternative to simply omitting the juvenile portion of the stable carbon isotope series, thus allowing greater sample depth to be retained.

Physical properties of wood in thinned Scots pines (Pinus sylvestris L.) from plantations in northern Spain

• The physical properties of wood and the associated variations within and between trees were evaluated by analysing 770 small specimens of clear wood from 11 Pinus sylvestris L. trees thinned from 3 plantations. • Within-tree variations in basic density or volumetric shrinkage increased with cambial age and decreased with increasing ring width. The effect of the height in the stem on wood properties was considered indirect and height was not included as an explanatory variable in the mixed models proposed to estimate basic density and volumetric shrinkage. • The models had random components for the intercept parameter and explained 52.5% of the total variance in basic density and 56% of the total variance in volumetric shrinkage. Linear shrinkage in the direction of the grain was extremely variable. • Between-tree variation and between-plot variation in the physical properties of wood were high, considering that all trees sampled were growing in similar sites and stands. It would then be desirable to predict physical properties of wood on living trees in order to use the quality of wood as a criterion for timber tree selection in thinnings. Scots pine / Pinus sylvestris / wood properties / thinning

Wood density within Norway spruce stems

We studied the variation in average wood density of annual rings, earlywood density, and latewood density in addition to ring width and latewood percentage within Norway spruce (Picea abies (L.) Karst.) stems from the pith to the bark, and from the stem base towards the stem apex. Moreover, the variation in wood density within annual rings was studied at the different heights and radial positions in the stem. The material consisted of 85 trees from central and south-eastern Finland. Variation between the annual rings accounted for 11–27% of the total variation in wood density. Only small differences (3–6%) in wood density were found between different heights in the stem. The largest (49–80%) variation in wood density was found within the annual rings. The difference in wood density between earlywood and latewood was smaller in the rings near the pith than in the outer rings. The increasing wood density from the pith outwards was related to increasing latewood density and latewood percentage, whereas the earlywood density increased only slightly from the pith outwards. In a given cambial age (i.e., given rings from the pith), the average wood density of annual rings increased with increasing stem height. In contrast, in the rings formed in the same calendar years (i.e., given rings from the bark), the average wood density of annual rings decreased with increasing stem height. The results of this study verify our knowledge of wood density variation and can further contribute to creating models to predict wood density.

The radial growth of pine stands in changing environmental conditions

Männipuistute radiaalkasvust muutuvates keskkonnatingimustes The changes in the radial growth in two consecutive generations of pine stands was investigated. Two pure pine stands were selected for this study. The both stands were represented by two consecutive generations growing at the same location and in the same site conditions. For determining the differences in the radial growth of successive stand generations the constant cambial age method was used. In analysis the average tree ring widths of stands at age of 30, 40 and 50 years was compared. The analysis showed that the radial growth of the younger stands at present exceeded that of the stands of old age when young. The increased N deposition and elevated CO2 level during the second half of the last century may have some positive influence for the growth of the studied young stands. The average temperature of the winter months in 1950-2000 has increased by 1 °C compared to that in 1850-1900. Therefore it may be assumed that long-term continuous warming may cause the altered growth response of pines.

Fresh-wood bending: linking the mechanical and growth properties of a Norway spruce stem

To provide data and methods for analyzing stem mechanics, we investigated bending, density and growth characteristics of 207 specimens of fresh wood from different heights and radial positions of the stem of one mature Norway spruce (Picea abies L. Karst.) tree. From the shape of each stress-strain curve, which was calculated from bending tests that accounted for shear deformation, we determined the modulus of elasticity (MOE), the modulus of rupture (MOR), the completeness of the material, an idealized stress-strain curve and the work involved in bending. In general, all mechanical properties increased with distance from the pith, with values in the ranges of 5.7-18 GPa for MOE, 23-90 MPa for MOR and 370-630 and 430-1100 kg m(-3) for dry and fresh wood densities, respectively. The first three properties generally decreased with stem height, whereas fresh wood density increased. Multiple regression equations were calculated, relating MOR, MOE and dry wood density to growth properties. We applied these equations to the growth of the entire stem and considered the annual rings as superimposed cylindrical shells, resulting in stem-section values of MOE, MOR and dry and fresh densities as a function of stem height and cambial age. The standing tree exhibits an inner stem structure that is well designed for bending, especially at a mature stage.

Standardization of Qilian Juniper ring-width series in the eastern margin of the Qaidam Basin

Standardization is one of the important procedures in dendroclimatology. We used abundant Qilian juniper (Sabina przewalskii Kom.) tree-ring samples from the eastern margin of the Qaidam Basin to develop a new standardization method, i.e. total growth curve (TGC). The samples that contained the complete pith and reached to the growing culmination around the 40th–60th year were used to fit TGC, and the generalized negative exponential function was used to fit the curve. Usually, most cores cannot reach the arboreal pith for some reasons and it is difficult to determine the arboreal cambial age. The empirical model of initial radial growth (IRG) was employed to estimate the number of rings missing from the pith by the same data and IRG model explained 90.9% of the variance. When developing the chronology, the cambial ages of cores that contained the complete pith were regarded as beginning from the first year and others were determined by the numbers of missing and included rings in the core. Standardization was accomplished by dividing each tree-ring series by corresponding TGC. The chronologies developed by TGC can retain more low-frequency variational information and TGC helps to develop more reliable tree-ring width chronology.

Croissance en diamètre et caractérisation de la limite entre bois juvénile et bois adulte chez l’okoumé des plantations au Gabon

The fast-growing hardwood, okoume (Aucoumea klaineana Pierre), is a major forest species in Gabon and is used principally for making plywood, but research into the growth and quality of this wood is scanty. Trees from natural forests are favoured for production, yet little information exists on wood characteristics from plantation trees. Therefore, we carried out a dendrochronological study along with measurements of wood lon- gitudinal modulus of elasticity (EL), density (Dw), dimensional stability parameters (longitudinal, radial and tangential shrinkage and fibre saturation point) and fibre cell morphology to determine if these properties were related to age in trees from two plantations. We then used segmented regression analysis to define the limit (breakpoint) between juvenile (JW) and adult wood (AW). Using monthly precipitation data, we were able to determine that one growth ring is formed per year, composed of a large light coloured ring formed during the long rainy season and a thick, dark band formed during the major dry season. However, thinner bands, analogous to false rings, may also form during the short dry and short rainy seasons. Ring width decreases from the pith to the bark, and the breakpoint between JW and AW was at 19 years old when trees from both plantations were pooled together. No differences in Dw or radial and tangential shrinkage occurred with cambial age. EL increased significantly up to the cambial age of 12-14 years, after which the increase with age was only slight and no breakpoint between JW and AW was found. With regard to mean longitudinal shrinkage, AW was found to form after the age of 13 years but fibre cell length was significantly longer after the age of 14.5 and 20 years, depending on the plantation of origin. Therefore, the boundary between JW and AW in plantation grown okoume occurs between the ages of 13 and 20 years, depending on the characteristic examined.

Effects of Silvicultural Practice, Tree, Cambial Age and Height on Wood Density Components of Plantation Poplar I-69 (Populus Deltoides CV. I-69/55) in China

In the study, the testing material of 6 trees of poplar clone I-69 (Populus deltoides CV. I-69/55) trees aged 12 years old were selected from the stands which located on the beech of Yangtse River in TianChang city, Anhui province, China. The wood density components (overall wood density (WD), earlywood density (DEW), latewood density (DLW) and relative wood density (DMax-DMin and DLW-DEW)) were measured using microdensitomitry methods. The effect of silvicultural practice, tree, cambial age and height of tree on wood density components was analyzed respectively. The results are as follows:1. The effect of silvicultural practice on wood density is significant at the 1% level, but not significant on earlywood density, latewood density and relative wood density.2. The tree effect on wood density, earlywood density, latewood density and relative wood density is not significant.3. The cambial age effect on wood density is significant at the 5% level, very significant on earlywood density, latewood density and relative density at the 0.1% level. There are large differences for radial variation patterns of wood density in 6 trees. In general, it has two kinds of radial variation patterns like increasing from pith to bark and decreasing outward at different heights. The wood density within a growth ring increases from earlywood to latewood continuously, but there exists large alteration when the cambial age is less than four years.4. The height effect on wood density including earlywood density and latewood density is significant differently in different trees. The wood density in the bottom (below 2m) is lower than the upper one (above 2m). The DMax-DMin fluctuated heavy below 2m and above 5m, but the DLW-DEW increases from bottom to 2m height and levels off upward.

Variability of latewood-widths and -stable isotope ratios in a sessile oak tree ( Quercus petraea (Matt.) Liebl.)

Axial variation of latewood-widths and -stable isotopes ( δ 13C and δ 18O) of a single sessile oak tree ( Quercus petraea (Matt.) Liebl.) was analyzed. The influence of sampling height was found to be weak for both, latewood-widths and -stable isotopes in the latewood. The observed trends with stem-height show clearly that possible effects due to cambial aging are overrated by annual effects. In addition, relations between samples from different stem-heights are strong for identical calendar years while they are poor for identical cambial age. This indicates that samples from both, living trees and historical wood can be taken from any height position of a trunk or beam as long they are free from anatomical abnormities. Simple correlation and Gleichläufigkeit were used for validation.

Bayesian analysis of Douglas-fir hydraulic architecture at multiple scales

We used a Bayesian hierarchical model to analyze the variation in xylem anatomy, hydraulic properties, and the relationship between anatomy and properties within Douglas-fir trees. The hierarchical scales in our study included fertilization treatments (fertilized and unfertilized), trees within the treatments, and positions within the trees. We measured tracheid diameter, tracheid length, percent latewood, number of pits per cell, density, and specific conductivity (K s) on seven positions in each of 16 fertilized and 16 unfertilized trees: the trunk at cambial age 52 (breast height), 25, and 5; a branch at cambial age 20 and 7; and a root at cambial age 42 and 22. Vulnerability to embolism was also measured on the oldest trunk, branch, and root positions. For any measurement, there was little variation between treatments, however, there was great variation among positions. Tracheid diameter, tracheid length, number of pits per cell, K s, and vulnerability to embolism decreased vertically from the roots to the branches. Correlations were evident between some positions for tracheid diameter, percent earlywood, pits per cell, and vulnerability to embolism, mostly in the fertilized treatment. We found evidence for large-scale relationships (among all observations from all trees) between density and tracheid diameter, K s and diameter, vulnerability and diameter, K s and pits per cell, and vulnerability and pits per cell. At a smaller scale of within position, however, usually only the branches and roots maintained the relationship.

Age trends in genotypic variation of wood density and its intra-ring components in young poplar hybrid crosses

Age related dynamics of genotypic, phenotypic, and environmental variation, clonal repeatability, and genotypic correlations for wood density and its intra-ring components were analyzed in four poplar hybrid crosses, Populus deltoidesP. nigra, P. trichocarpaP. deltoides, P. max- imowicziiP. balsamifera, and P. balsamiferaP. nigra, as well as P. deltoides. Using X-ray densitometry, measurements were taken on increment cores sampled in four clonal trials at 10 and 12 years of age from ramets of 19 clones. Wood density of all hybrid crosses was highest at the pith and decreased with increasing cambial age. The significance of the hybrid cross effect increased with age for mean wood density, dry fiber weight, and ring width. The coefficient of genotypic variation of cumulated mean wood density was rather stable over the 10-year period at all three sites, and ranged from 4.8-6.8%. Clonal repeatability increased with age from 0.46 to 0.79, mainly because of decreasing random variation. Corresponding genotypic parameters for individual rings varied greatly with age and across sites. Significance of the site effect on wood density tended to decrease with age. Significant negative genotypic correlations between ring width and wood density were found at only two of the four sites and they weakened with age. Age-age genotypic correlations between wood densities at ages 10 and younger were strong and significant from age 6 and over. This trend suggests that selection before this age would be unreliable. poplar hybrids / clones / wood density / radial growth / age trend / genotypic variation / repeatability / genotypic correlation

Tree height and age-related decline in growth in Scots pine (Pinus sylvestris L.)

Growth and seasonal water use was measured amongst trees growing in an old growth Scots pine forest in the Scottish Highlands. Three sites which differed in their recent management history and contained old and naturally regenerated young trees growing together were monitored in the field. Our results showed a clear decrease in growth efficiency with age, from values of around 0.25 kg m(-2) leaves year(-1) in approximately 25-year-old trees to less than 0.1 kg m(-2) leaves year(-1) in trees over 200 years old. When the old trees in one of the field sites were released from competition by thinning, their growth efficiency reverted to that of coexisting young trees, indicating that the decline in growth was reversible. This is consistent with the results of a parallel study showing that cambial age had no effect on the physiology or growth of grafted seedlings originating from the same population studied here (Mencuccini et al. 2005). Our detailed study of tree water use in the field showed an overall decrease in whole-tree hydraulic conductance and stomatal canopy conductance with tree height in the unthinned stands, in agreement with the hydraulic limitation hypothesis. However, the effect of this reduction in hydraulic efficiency on growth was comparatively small, and old trees also showed consistently lower nitrogen concentrations in needles, suggesting that hydraulic and nutritional factors combined to produce the decline in growth efficiency with age observed in the studied populations.

Evaluating growth strain of Eucalyptus globulus Labill. from SilviScan measurements

Abstract Longitudinal surface strain was measured or estimated using three different methods along the stems of nine trees of 10-year-old Eucalyptus globulus Labill. Wood samples were collected close to the location where the strain was measured or estimated. Microfibril angle (MFA), cellulose crystallite width (Wcryst), microdensity and Young's modulus along the grain (EL) were determined using the SilviScan-2 technology at high spatial resolution. Relationships of measured strain and estimated strain to wood properties were established. The quality of the relationships depends on a particular wood property. Strain was more closely related to mean Wcryst than to any other wood properties. Its relationship with MFA was the next closest. Based on the results of regression analysis, we propose that Wcryst may be suitable for the prediction of surface strain at a moderate level of reliability. Adding measurement of MFA, microdensity and EL does not significantly improve the prediction quality. The strain measurement method also affects the results. The best relationships were obtained with longitudinal displacement measured by the CIRAD method. Strain measured by the strain gauge method gave weak relationships, possibly owing to variation in the cambium age of the specimens.

Extraction of features from ultrasound acoustic emissions: a tool to assess the hydraulic vulnerability of Norway spruce trunkwood?

The aim of this study was to assess the hydraulic vulnerability of Norway spruce (Picea abies) trunkwood by extraction of selected features of acoustic emissions (AEs) detected during dehydration of standard size samples. The hydraulic method was used as the reference method to assess the hydraulic vulnerability of trunkwood of different cambial ages. Vulnerability curves were constructed by plotting the percentage loss of conductivity vs an overpressure of compressed air. Differences in hydraulic vulnerability were very pronounced between juvenile and mature wood samples; therefore, useful AE features, such as peak amplitude, duration and relative energy, could be filtered out. The AE rates of signals clustered by amplitude and duration ranges and the AE energies differed greatly between juvenile and mature wood at identical relative water losses. Vulnerability curves could be constructed by relating the cumulated amount of relative AE energy to the relative loss of water and to xylem tension. AE testing in combination with feature extraction offers a readily automated and easy to use alternative to the hydraulic method.

Age trends of genetic parameters of spiral grain in hybrid larch F1 and implications for efficiency of early selection

Age trends in variance components and heritability were estimated from the spiral grain angle of rings 2–25, as counted from the pith in hybrid larch (Larix gmelinii var. japonica × Larix kaempferi) F1. Age-age genetic and phenotypic correlations and the optimum selection age for spiral grain were also calculated. Wood samples were collected from 95 29-year-old trees belonging to 19 full-sib families in a progeny test plantation in Hokkaido, northern Japan. Spiral grain angle data were obtained by the splitting method. Mean grain angles at growth rings used for the analyses were calculated as the arithmetic mean of angles up to respective rings. Generally, the additive genetic variance for mean grain angle decreased with increasing ring number. Although dominance variance was comparatively high near the pith, it decreased to zero in subsequent growth rings. Highest heritability estimates of mean grain angle occurred at ring 4 and then declined with age, ranging from 0.45 down to 0.20. Age-age phenotypic correlations were higher than genetic correlations, especially those involving early growth rings. Optimum selection ages for spiral grain based on genetic and phenotypic correlations were estimated as 3 and 4 years (cambial age), respectively, in which maximum gain efficiency per year were obtained.

06/01003 System approach to the energy analysis of complex buildings: Ziebik, A. et al. Energy and Buildings, 2005, 37, (9), 930–938.

Written sources and archaeological evidence suggest that coppicing was a common practice in past woodland management. Depending mainly on the length of rotations, coppices provided wood products of various sizes, and coppice-wood has been identified in fuel-wood remains as well as in timber studies. Assigning the origin of the wood analyzed to coppice is based on observation of “typical growth patterns”: an even-age structure and a rapid decrease in ring-width with age are used nowadays. However, the wide variety of coppice practices and the variability observed in living-tree analogs make it difficult to draw definitive conclusions. To contribute to improving coppice-wood identification, the present study analyzed differences in growth and tree-ring anatomy between living sessile oaks from a mixed stand of coppiced and seeded trees.Stems were compared based on ring-width, early- and late-wood widths, number and size of the earlywood vessels, and tissue proportions measured at different heights. The growth of coppiced trees was found to be faster than that of seeded trees, in height at cambial ages between 3 and 5 years and in diameter at 5–8 years. A quantitative anatomy study showed that tree rings from coppice shoots had smaller and more numerous vessels per unit surface area and a weaker hydraulic conductivity. Earlywood width, which can be acquired on archaeological wood much more easily than vessel surface, was significantly greater in the sample of seeded trees. Linear discriminant analysis performed on the data used to model earlywood width (leave-one-out procedure) correctly classified 77% of coppice and 54% of seeded trees when the radius exceeded 1.66 cm and offers promising perspectives for dendro-anthracology and dendrochronology. Growth and anatomical differences between coppiced and seeded trees mixed in the same stand were observed while other sources of variability (site condition, competition, species) were constrained.