IntensIve sIlvIculture - Forest Science Labs - Research Network ...

310. Kershaw, J.A., Jr. and D.A. Maguire. 1996. Crown structure in western hemlock, Douglas-fir, and
grand fir in western Washington: horizontal distribution of foliage within branches. Canadian-
Journal-of-Forest-Research 26(1): 128-142.
Keywords: fertilization
tree morphology
137
Abstract: Horizontal distribution of foliage within individual branches was explored for
western hemlock (Tsuga heterophylla), Douglas fir (Pseudotsuga menziesii) and grand fir (Abies
grandis), three major tree species in the Pacific Northwest. Weibull, beta , normal, and Johnson's
SB distributions were assessed for their ability to conform to the empirical foliage distributions.
Moment-based parameter recovery and parameter prediction methodologies were applied. On the
basis of the rank of individual branch chi superscript 2-values, the beta distribution performed
best under parameter recovery, while Johnson's SB distribution was best in terms of total sum of
chi superscript 2-values. Overall, few differences between the four distributions were observed. A
system of moment-based parameter prediction equations was developed from branch dimensional
and positional measures. The prediction equations showed that the ratio of relative distances from
the stem to mean foliage density increased with increasing branch size. This relative increase was
enhanced with increasing depth into crown for western hemlock, but not for Douglas fir or grand
fir. Again, the beta distribution, based on predicted moments, followed most closely the empirical
distributions on the basis of the ranks of chi superscript 2-values. The normal distribution was the
best in terms of total sum of chi superscript 2-values. As expected, moment-based parameter
recovery produced smoothed distributions that followed more closely the observed empirical
distributions; however, parameter prediction provides a methodology for predicting distributions
when empirical moments are not available. No significant (p >0.05) differences in horizontal
foliage distribution were found between sites or fertilizer (0 or 225 kg N/ha as urea) treatments.
311. Ketchum, J.S., R. Rose and B. Kelpsas. 1999. Weed control in spring and summer after fall
application of sulfometuron. Western Journal of Applied Forestry 14:80-85.
Keywords: site preparation
mechanical preparation
chemical preparation
stand conditions
Abstract: This study tested the residual spring and summer efficacy of sulfometuron after
applications in the autumn in second growth Douglas fir (Pseudotsuga menziesii) with red alder
(Alnus rubra) and bigleaf maple (Acer macrophyllum) forest sites in the central Coast Range,
Oregon, USA, which had been harvested in the summer. Sulfometuron alone (S) and
sulfometuron plus imazapyr and glyphosate (SIG) were applied to vegetation on mechanically
scarified sites and unscarified sites. The applications were replicated each month throughout
autumn 1994. Vegetation cover was assessed in mid-June and mid-August 1995. The SIG
treatment gave better control of vegetation than the S treatment, although cover was significantly
lower for both herbicide treatments (9% to 54% for summed cover) compared to the control site
(64% to 104% for summed cover). On scarified sites, the month of application, early or late
autumn, did not significantly influence the efficacy of either treatment. On unscarified sites,
however, applications of the SIG treatment later in autumn were less effective than early autumn
treatments. Results suggest that autumn applications of sulfometuron are still effective in spring
and may eliminate the need to treat sites again in the spring in order to achieve effective weed
control.