The effect of age and sample position on eucalypt tree-ring width series

Abstract

In this study, we examine within-tree variance in proportionate tree-ring width (p rw ) and correlation between radii (r wt ), samples (r bh ), and trees (r bt ) in four eucalypt species common throughout eastern Victoria, Australia. In all species and sites studied, rwt and rbh differ significantly between cambial-age and sample-height classes. Differences between rwt and rbh are nonsignificant between tree-age or radial-azimuth classes. Significant differences in prw exist between cambial-age, tree-age, and sample-height classes and between radii on different compass bearings. Whilst differences in rwt and rbh between cambial-age classes appears to be the result of variation in mechanical demands with increasing stem size, stem deformation may account for differences between sample-height classes. Variation in prw appears to be due to stem geometry, stem eccentricities associated with root buttressing, and tree-age dependent variation in the rate of radial growth. No significant differences in rbt exist between sample-height classes. Analysis of the expressed population signal statistic indicates that site-level and species differences are far more significant than sample position on variance within tree-ring width series collected from eucalypts. We discuss the implications of the current work for eucalypt dendroclimatology.Résumé : Dans cette étude, nous avons examiné la variance intra-arbre de la largeur proportionnelle des cernes annuels (p rw ) et les corrélations entre les rayons (r wt ), les échantillons (r bh ) et les arbres (r bt ) chez quatre espèces d'eucalyptus communes dans la partie est de la région de Victoria, en Australie. Chez toutes les espèces et dans tous les sites étudiés, r wt et r bh diffèrent significativement entre les classes d'âge cambial et de hauteur des échantillons. Par contre, r wt et r bh ne diffèr-ent pas significativement entre les classes d'âge des arbres et d'azimut des rayons. Des différences significatives existent dans le cas de p rw entre les classes d'âge cambial, d'âge des arbres et de hauteur des échantillons ainsi qu'entre les rayons correspondant à différentes orientations. Alors que les différences de r wt et r bh entre les classes d'âge cambial semblent causées par la variation du stress mécanique avec l'augmentation de la taille de l'arbre, la déformation de la tige peut expliquer les différences entre les classes de hauteur des échantillons. La variation de p rw semble causée par la géométrie de la tige, par les excentricités de la tige associées à la formation de contreforts à la base du tronc et par la variation du taux de croissance radiale qui dépend de l'âge des arbres. Dans le cas de r bt , il n'y a aucune différence significative entre les classes de hauteur des échantillons. L'analyse de la statistique du signal exprimé par la population indique que les effets du site et de l'espèce sont de loin plus importants que celui de la position de l'échantillon sur la variance intra-arbre des séries de largeur des cernes annuels collectées sur les eucalyptus. No...

Climate effects on growth differ according to height and diameter along the stem in Pinus pinaster Ait.

“…Likewise, the signal-noise ratio increased with sample height of the tree-ring series. Therefore, the response of radial growth to climatic variations increased with height along the stem, as previously reported by other studies (Brookhouse & Brack 2008, Kerhoulas & Kane 2012, Latte et al 2016). …”

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“…However, several studies have shown that radial growth at breast height may not be representative of radial growth patterns along the stem (Brookhouse & Brack 2008, Chhin et al 2010, Kerhoulas & Kane 2012, Sohn et al 2012, Latte et al 2016. Differing rates of growth along the stem can be caused by vertical gradients in hydraulic constraints and priorities for carbon allocation.…”

The Potential of Tree Rings in Eucalyptus pauciflora for Climatological and Hydrological Reconstruction

“…The sample height for our samples is unknown. However, recent analysis (Brookhouse and Brack, in press) demonstrates that sample height does not significantly affect the consistency of climate sensitivity between trees. Thus, it is unlikely that sample height significantly affects the climatological sensitivity of our data.…”

From a tree to a stand in Finnish boreal forests: Biomass estimation and comparison of methods

“…The width of a tree ring formed in one year varies along the stem of a tree, while the width of consecutive rings at a given stem position fluctuate in radial direction (e.g. Brookhouse & Brack 2008). Such stem-vertical and radial variations in ring width are due either to the allometric nature of tree growth (Niklas 1994) or the effects of variation in environmental factors (Fritts 1976, Cook and Kairiukstis 1989, Eronen and Zetterberg 1996, Schweingruber 1996, in particular, climate (e.g.…”