Heartwood Area Research Articles

The Effect of Adelgid-Altered Wood On Sapwood Conductance of Fraser Fir Christmas Trees

Potential sapwood flow rates were measured for Fraser fir sterns that previously had been infested by the balsam woolly adelgid. The amount of abnormal wood produced during infestation was inversely related to the flow rate and linearly related to the amount of heartwood area. These results support the hypothesis that abnormal wood production associated with adelgid infestation can lead to water stress in the crowns of infested trees. The data also suggest that adelgid infestation accelerates the formation of heartwood.

Total wood, sapwood, and heartwood in branch bases of three conifers

Branches were cut from forest-grown, 15- to 85-year-old Picearubens, Pinusstrobus, and Tsugacanadensis trees. For 1139 branches we measured (i) cross-sectional sapwood, colored heartwood, and total wood areas at the branch base, (ii) dry weight of the needles and wood, and (iii) age. Branch age was a poor predictor of wood areas at the branch base. Regression analysis showed that branch wood dry weight was the best predictor of total wood area. Sapwood area was predicted equally well by needle dry weight or as a percentage of total wood area. The prediction was improved by using needle dry weight plus total wood area as variables. The mean ratio of sapwood area to needle dry weight was 0.72 mm2/g for Picearubens, 1.19 mm2/g for Tsugacanadensis, and 1.62 mm2/g for Pinusstrobus. Colored heartwood formed in the center of all branches older than 8 years. Heartwood area was a greater proportion of total wood area in older branches than in younger branches of any given tree, although absolute heartwood area was as variable as total wood area. The best estimates of heartwood area were obtained by subtracting estimates of sapwood area from total wood area. Heartwood area of the oldest branches (8–46 years) from each tree was 7–96% of total wood area at the branch base.

The adjustment of growth, sapwood area, heartwood area, and sapwood saturated permeability of balsam fir after different intensities of pruning

Balsam fir trees established from advanced regeneration following a clear-cut in 1970 were pruned in June 1985 to live crown ratios of 0.6, 0.4, and 0.2 compared with control trees, which had live crown ratios of 0.8. After two growing seasons, we investigated the homeostatic adjustment of these trees to the loss of their foliage. The height growth, basal area growth, sapwood cross-sectional area, heartwood area, and sapwood saturated permeability of the trees that were pruned to a 0.6 live crown ratio were not significantly different from those of the controls. On the other hand, height growth increment following pruning was reduced 16.7 cm (23%) and 19.5 cm (27%) for the trees pruned to 0.4 and 0.2 live crown ratios, respectively. Furthermore, basal area growth following pruning was reduced 3.2 cm2 (30%) and 6.5 cm2 (61%), respectively. While trees in both the 0.4 and 0.2 live crown ratio pruning treatments did adjust their breast height sapwood area in response to the removal of foliage, the nature of this adjustment differed between the two treatments. For the trees with the 0.4 live crown ratio, sapwood area was reduced because of a reduction in basal area growth but the area of heartwood remained unchanged. For the trees with the 0.2 live crown ratio, the changes in sapwood area were due both to a reduction in basal area growth and an expansion of the heartwood. The saturated permeability of sapwood was not significantly affected by pruning. The adaptive implications of balsam fir's response to the loss of foliage are discussed in terms of the optimizing the allocation of a limited amount of available carbon.

Distribution and phenolic composition of sapwood and heartwood in Abiesgrandis and effects of the balsam woolly aphid

The distribution of sapwood and heartwood was analyzed at three different height levels in Abiesgrandis infested and non-infested with balsam woolly aphid. In non-infested trees, there was a highly significant regression between percentage heartwood age and disk age and a less significant regression between percentage heartwood area and disk area. Aphid infestation increased both the number of annual rings of heartwood and the heartwood area. The amount of heartwood in the infested trees was highly variable and dependent upon the degree of aphid infestation. Phenolic composition of A. grandis was similar to western hemlock, with heartwood containing matairesinol, hydroxymatairesinol, conidendrin, and an unknown phenolic glucoside. Sapwood contained several leucoanthocyanidins. Aphid infestation did not alter the phenolic composition of the heartwood, but it did cause the occurrence of a new phenolic in the sapwood. The possible causes of the increased amounts of heartwood in infested trees are discussed.