Abundance of natural regeneration and growth comparisons with planted seedlings 10–13years after commercial thinning in 50-year-old Douglas-fir, Douglas-fir/western hemlock, Oregon Coast Range

2013 ◽  
Vol 292 ◽  
pp. 96-110 ◽  
Author(s):  
Mark R. Nabel ◽  
Michael Newton ◽  
Elizabeth C. Cole
2008 ◽  
Vol 23 (3) ◽  
pp. 142-148 ◽  
Author(s):  
Nicole L. Younger ◽  
Hailemariam Temesgen ◽  
Sean M. Garber

Abstract For nearly 20 years, foresters in the Oregon Coast Range have been witnessing a substantial decease in Douglas-fir (Pseudotsuga menziesii var. menziesii [Mirb.] Franco.) vigor and volume, caused by Swiss needle cast (SNC) disease. Currently, there are no solutions and disease severity is expected to worsen in coming years, but there is hope that aerially applied treatments of sulfur may be able to alleviate the effects of SNC. In this trial, volume, taper, and other attributes were examined on 120 Douglas-fir trees heavily infected with SNC for response to treatments of (1) sulfur, (2) sulfur + nutrients, and (3) control, which received no treatment. Tree attributes such as crown ratio, crown width, and sapwood area at crown base showed no statistically significant differences between treatments. Means of both foliage mass and years of needle retention also were not different between sulfur and control treatments. However, both of these attributes were different between the sulfur + nutrient and control treatments (P = 0.0599, 0.0205). Using a modified Kozak's (1988) variable exponent model form, taper analysis indicated that the taper of trees within the sulfur treatment was not significantly different from the taper of the control, while the sulfur + nutrient treatment showed decreased taper compared with the control (P =<0.0246). This improvement of taper in the sulfur + nutrient stand, however, has not translated into a statistically significant increase in cubic foot volume removed in the first thinning after adjusting for tree size differences between treatments. Comparing treatments by monetary value of removed trees in the first thinning also showed no significant differences, thereby implying that sulfur and sulfur + nutrient treatments are not able to increase volume enough in 4 years to produce additional profits in the first commercial thinning. It should be noted, however, that all conclusions drawn from this study are essentially from a single replication, and the scope of inference applies only to this particular type of stand in the Oregon Coast Range.


2007 ◽  
Author(s):  
Richard E. Miller ◽  
Jim Smith ◽  
Paul W. Adams ◽  
Harry W. Anderson

2009 ◽  
Vol 39 (3) ◽  
pp. 580-595 ◽  
Author(s):  
Elizabeth Cole ◽  
Michael Newton

This study initiated a two-aged forest stand structure by underplanting 50-year-old stands, primarily of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) and Douglas-fir – western hemlock ( Tsuga heterophylla (Raf.) Sarg.), thinned to 19–33 m2/ha on interior and coastal sites in the Oregon Coast Range. Douglas-fir, grand fir ( Abies grandis (Dougl. ex D. Don) Lindl.) (interior site only), western hemlock, and western redcedar ( Thuja plicata Donn ex D. Don) were planted following thinning either uniformly or in gaps of 0.06 or 0.1 ha. Understory vegetation treatments included (i) a preharvest site preparation herbicide application and an untreated control at both sites and (ii) a postharvest herbicide release treatment at the interior site. Planting conditions and stock at the interior site were not ideal, so survival was adjusted for first-year mortality. Adjusted 10 year survival ranged from 27% to 56% for Douglas-fir, 47% to 65% for western hemlock, 61% to 80% for grand fir, and 78% to 96% for western redcedar. Tenth-year survival at the coastal site ranged from 79% to 92% for Douglas-fir, 61% to 75% for western hemlock, and 67% to 86% for western redcedar. All species grew moderately well beneath the lowest-density overstories, and size was better within gaps than matrices for most species. Understory site preparation improved size for most species. Browsing on Douglas-fir and western redcedar impacted size on both sites.


1987 ◽  
Vol 2 (4) ◽  
pp. 117-119 ◽  
Author(s):  
Samuel S. Chan ◽  
John D. Walstad

Abstract The response of Douglas-fir (Pseudotsuga menziesii) saplings to overtopping vegetation on three northeast-facing sites in the Oregon Coast Range was studied for two years. As amount of overtopping brush increased, sapling growth (as indicated by size) generally decreased. Basal stem diameter growth was most reduced, but similar reductions in growth occurred for tree height and other morphological features. West. J. Appl. For. 2(4):117-119, October 1987.


2006 ◽  
Vol 21 (3) ◽  
pp. 117-122 ◽  
Author(s):  
Darrell W. Ross ◽  
Bruce B. Hostetler ◽  
John Johansen

Abstract Douglas-fir beetle populations were monitored before and after thinning and felling of trees to create down wood in an 88-year-old Douglas-fir plantation in the Oregon Coast Range. Treatments included an unthinned control, thinning to a target of 75 trees/ha, and thinning to a target of 150 trees/ha. Actual mean tree densities on the plots after thinning were 406, 102, and 154, for the control, 75 trees/ha, and 150 trees/ha treatments, respectively. Fifty trees/ha were felled and left on all thinned plots to create down wood for ecological values. Catches in pheromone-baited traps indicated that the local beetle population increased for 1 year in response to felling and leaving large diameter trees in partial shade. Douglas-fir beetle entrance holes and brood were significantly more abundant on the sides of felled trees and wood borers were significantly more abundant on the upper surface suggesting that treatments that provide maximum exposure of felled trees will create the least favorable habitat for Douglas-fir beetles. However, there were no differences in Douglas-fir beetle entrance holes or brood densities in felled trees between the two thinning intensities. Douglas-fir beetle-caused tree mortality was significantly higher on thinned plots with residual felled trees compared with unthinned controls, although infestation levels were low on all plots (<2 trees/ha). The small increase in beetle-caused tree mortality associated with leaving felled trees would be unlikely to interfere with resource management objectives. These results are applicable to mature, managed forests west of the Cascades with relatively low Douglas-fir beetle populations. In different regions and stand types, or under different environmental conditions, beetle populations could increase to higher densities, remain at high densities longer, and cause higher levels of tree mortality. West. J. Appl. For. 21(3):117–122.


2001 ◽  
Vol 16 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Walter W. Kastner ◽  
Steve M. Dutton ◽  
David M. Roché

Abstract Douglas-fir (Pseudotsuga menziesii var. menziesii) seedlings grown from three seed sources were evaluated for 5 yr on a high-disease-hazard site for their relative tolerance to Swiss needle cast. The seed sources were: (1) seed collected from trees showing an apparent degree of tolerance to Swiss needle cast in natural stands in the coastal fog belt, (2) open-pollinated seed orchard seed collected from random single-pair crosses of parent trees in natural stands outside of the coastal fog belt, but west of the Oregon Coast Range summit, whose progeny demonstrated an apparent degree of disease tolerance in coastal Douglas-fir progeny test sites, and (3) standard reforestation seed purchased from a commercial vendor. There were no significant differences among seed sources in basal diameter and total height for all five growing seasons. Needle retention varied among seed sources over the 5 yr period, but current-year needle retention did not vary significantly after the fifth growing season, and retention of 1- and 2-yr-old needles was relatively low for all seed sources. The intense disease pressure on this site may have overwhelmed expression of disease tolerance among seed sources. We do not recommend planting Douglas-fir on such high-hazard sites. West J. Appl. For. 16(1):31–34.


1998 ◽  
Vol 28 (8) ◽  
pp. 1207-1212 ◽  
Author(s):  
Rick G Kelsey ◽  
Gladwin Joseph

Diseased and healthy Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) were identified at two black-stain root disease centers, caused by Leptographium wageneri var. pseudotsugae Harrington & Cobb, in the Oregon Coast Range near Coos Bay. Phloem and sapwood near the root collar were sampled monthly for 1 year, whereas roots were sampled in October and November. Ethanol concentrations in sapwood of diseased trees near the root collar were 4-24 times higher than in healthy trees for all months of a year, except January and June. Roots from diseased trees in October had 5 times more ethanol in the phloem and 19 times more ethanol in the sapwood than corresponding tissue from healthy trees. Ethanol concentrations in roots from diseased trees in November were no different from October. Within trees, ethanol concentrations varied substantially among positions around the root collar and among different roots. Ethanol may play an important role in the biology of L.wageneri and beetle-pathogen interactions in Douglas-fir. Ethanol also may be useful in detecting stressed or diseased trees.


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