Vertical heartwood variation patterns and prediction of heartwood volume in Pinus canariensis Sm. uri icon

abstract

  • Heartwood and sapwood distribution along the stem were assayed in 26 Canary Island pines growing along the natural range of the species at the Canary Archipelago. Trees were sampled at breast height and approximately every 2 m up to the lowest section without heartwood. Heartwood and sapwood thickness, together with age and radial growth traits were measured in each section. Heartwood tapered towards the top of the tree And disappeared at a certain height. Sapwood distribution was more variable among individuals; sapwood width was almost constant in some individuals but tapered slightly or with a curvilinear variation in others. Two general patterns of heartwood and sapwood variation were defined, one characterised by a constant decrease in heartwood percentage and subsequently a slight sapwood variation along the stem (uniform pattern) and another one with a peak in heartwood percentage at a height between 4 and 8 m (irregular pattern). The relative crown height to total tree height was significantly higher in the second group, averaging 49% versus 32% in the uniform group. A mechanical-physiological hypothesis is given to explain this result in the light of similar results in other species. A model including heartwood radius at breast and tree height as predicting variables was able to explain 90% of heartwood radius at a given height in the stem. A similar model with sapwood width at breast height explained 80% of sapwood width variation along the stem. Heartwood volume was predicted by means of log-linear regression models including heartwood diameter at breast height and tree height (r(2) = 97.5%). Sapwood volume was better predicted through stem diameter at breast height and tree height (r(2) = 92.7%). (C) 2002 Elsevier Science B.V. All rights reserved.

publication date

  • 2003
  • 2003