Relationships between foliar number and the cross-sectional areas of sapwood and annual rings in red oak (Quercus rubra) crowns
1993
White, D.A.
Correlations and functional relationships of sapwood and annual ring cross-sectional areas versus the number of leaves supported inside the live crowns of red oak (Quercus rubra L.) were found, based on analyses of six 20- to 25-year-old oaks from monocultures in southern Ontario. Differences in numbers of leaves supported across intervals inside the crowns were compared, using correlation analyses, with the corresponding differences in conductive sapwood (outer two annual rings) cross-sectional areas, and the current and previous year's annual ring's cross-sectional areas. These analyses showed that the current year's annual ring area had a lower correlation with number of current leaves supported (R = 0.918, P < 0.0001) than did the previous year's annual ring area (R = 0.953, P < 0.0001) or the conductive sapwood area (R = 0.939, P < 0.0001). Functional relationships between foliar numbers supported and sapwood and annual ring cross-sectional areas inside the live crowns were found with regression analysis. The previous year's ring area (PRA) had a more linear relationship to leaf counts (FQ) than did conductive sapwood area and current annual ring area. FQ = 815.6 leaves/cm2 X PRA(1.14) - 137.9. The close relationship between current foliage and previous annual ring area may reflect a developmental link between foliar primordia, which will become the following year's foliage, and the cross-sectional area of the supporting xylem.
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