Climate and growth influences on wood formation and utilisation

Abstract

Wood is produced by a complex sequence of interactions between gene–protein expression and the local environment. It is produced by the vascular cambium, an essentially two-dimensional surface of meristematic cells covering the tree stem. The growth of any individual cambial cell is dependent on its immediate environment, its genetic makeup and its previous history. The immediate environment (climate and nutritional factors, growth regulators and physical stresses) varies continuously over time. Consequently, the local conditions in any part of the cambium influencing wood formation at any given instant are unique. The distribution of these conditions can be influenced by longitudinal gradients (stem base to apex), circumferentially or by local factors, such as proximity to branches. Therefore, it is not surprising that the variation in wood properties within a stem is large and that in seasonal climates, the greatest variation is typically found within an annual ring. A great advantage for the study of wood is that the net product of seasonal processes is recorded in the wood structure of the annual ring. Thus by studying the pattern of wood property variation, within the context of its growth history, we can gain insight into cause-andeffect relationships within the context of the drivers of wood variability. Combining this with temporal, high-resolution measurements of stem growth, weather, gene expression, cambial structure, and canopy or root phenology enables us to better understand wood formation and the causes of variability in wood properties. CSIRO has, over recent years and in partnership with industry and other research providers, been exploring the causes of wood variability along these lines, using a number of different but related research disciplines. Combining genetic (molecular and quantitative), environmental and silvicultural studies, using technological advances such as SilviScan™ and near-infra-red prediction of wood properties, and integrating understanding gained into predictive process-based models such as TreeRing, CaBala and CAMBIUM, offers an opportunity to advance our understanding and management of wood variability in plantation forests.

Keywords: dendrometers; near infra red; phenology; process modelling; SilviScan; wood variability

Southern Forests 2008, 70(2): 155–167