Canopy profiles of some Piedmont hardwood forests

Abstract

Relationships between canopy profiles and site quality were examined in 11 old, uneven-aged (>180 years) hardwood forests in the Piedmont of eastern North Carolina. Site fertility was indexed by extractable soil calcium and phosphorus, by the content of calcium, phosphorus and nitrogen in litter fall, and by the aboveground net primary productivity of each stand. Canopy profiles were indexed by the leaf area index for each 3.3-m height interval. Total leaf area index correlated highly with most measures of site fertility, but we found no clear patterns between canopy profiles and any measure of site fertility. We conclude that site fertility is reflected in broad ecosystem-level variables such as total leaf area index and stand productivity, but that detailed patterns such as canopy profiles relate strongly to specific stand composition, age structure, and history.

Vertical leaf area distribution, light transmittance, and application of the Beer–Lambert Law in four mature hardwood stands in the southern Appalachians

“…composed 71% of the total stand LAI. These values are within the range of LA1 values reported for other eastern deciduous forests (Aber 1979;Hedman and Binkley 1988;Monk and Day 1988;Chason et al 1991;Ellsworth and Reich 1993). While general relationships among LA1 and stand structure characteristics have been shown in other studies (e.g., Gresham 1982), no clear relationships (based on scatterplots) between LA1 and other stand attributes (Table 1) were found in our study.…”

“…In July 1993, we used the line-intercept technique (MacArthur and MacArthur 1961) in combination with litter-fall LA1 estimates to estimate vertical LAI. We chose this technique because destructive sampling was not possible (i.e., leaves accessed from the towers were also used in physiological studies) and modified versions of this technique have been previously used to estimate vertical LA1 profiles in hardwood canopies (Aber 1979;Hedman and Binkley 1988). A vertical line (string) with a plumb bob attached to the bottom was lowered from the top of the canopy to the forest floor.…”

Stand structure and foliage distribution in Quercus pubescens and Quercus cerris forests in Tuscany (central Italy)

“…The Q. pubescens stand had a larger fraction of LAI distributed in the lower half of the canopy, while the Q. cerris stand showed a slight skew towards the upper half of the canopy, which indicates better growing conditions as well as more competition for light in the latter stand. A great variability including upward, downward, and uniform vertical LAI distributions in hardwood stands has been found in other studies (e.g., Hedman and Binkley, 1988;McIntyre et al, 1990;Vose et al, 1995). In this study, the vertical distribution of LAI was most likely determined by stand structure and species composition.…”

Influence of nutrient availability, stand age, and canopy structure on isoprene flux in a Eucalyptus saligna experimental forest

“…Modeled leaf area distribution in 6‐year fertilized, 6‐year unfertilized, and 2‐year fertilized E. saligna canopies. Values were derived from measurements in one plot per treatment [ Hedman and Binkley , 1988]. Layer 1 is at the canopy top.…”

“…All estimates of LAI were corrected with an allometric equation that was developed with harvested leaves from the buffer areas of the 18 plots. The distribution of leaf area within the canopy was determined in one plot of each plot type as described by Hedman and Binkley [1988].…”