Effects of crown size on wood characteristics of Corsican pine in relation to definitions of juvenile wood, crown formed wood and core wood

Abstract

Current use of the terms ‘juvenile wood’, ‘crown formed wood’ and ‘core wood’ is confusing: some authors have used the terms synonymously, while others have used each term in a more restricted sense to imply the region of a log where wood structure and properties are influenced by ring number from the pith (or distance from it), or by crown size. The present work was designed to clarify the use of these terms, since their definition is relevant to interpretation of the influence of silvicultural management on the wood quality of a log. Wood production and properties were studied in 23‐year‐old suppressed, co‐dominant and dominant Corsican pine ( Pinus nigra var. maritima ) trees, in relation to crown size as determined by leaf dry weight profiles. At comparable ring number from the pith, differences in crown size from suppressed to dominant tree class resulted in a substantial increase in average ring width, decrease in mean percentage latewood, MOR, MOE and maximum compression strength, inconclusive differences in mean specific gravity, and negligible differences in tracheid length. From these trends, it is here suggested that ‘juvenile wood’ should be defined as the region around the pith in which there are inherent changes in structural characteristics associated with cambial age, independent of crown influences. The term ‘crown formed’ wood should be used to describe fluctuations in wood structure associated with the size of the crown, which are superimposed upon the inherent trends due to cambial age. The term ‘core wood’ should be retained for use in a more generalized sense, indicating the central region of the log where structure and properties are variable and differ from those of the outer wood.