Conifer response to three silvicultural treatments in the Oregon Coast Range foothills

This study assessed growth, condition, and mortality of residual trees one decade after harvest across three silvicultural treatments in thirty 85- to 125-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stands in the Oregon Coast Range foothills. Group-selection cuts had 33% of the entire stand volume extracted as patches approximately 0.20.8 ha in size; two-story regeneration harvests had 75% of the volume extracted, and 2030 residual trees/ha were left; clearcuts had all trees removed, except for 1.2 trees/ha. One decade after harvest, tree basal area, diameter, and height growth, and crown width and fullness did not differ between silvicultural treatments. In contrast, live crown ratio was largest in clearcuts (0.74), and the proportion of trees with epicormic branching was highest in two-story stands (35%). Overall, 45% of trees had more basal area growth in the decade after harvest than in the previous decade. Residual green trees in clearcuts and group-selection stands experienced the highest and lowest percentage mortality, respectively (30.6% vs. 0.2%). Our results reflect little differentiation in the characteristics of trees growing under three silvicultural conditions one decade after harvest. However, percent residual green tree mortality increased with increasing harvest intensity.

Download Full-text

Basal area growth, carbon isotope discrimination, and intrinsic water use efficiency after fertilization of Douglas-fir in the Oregon Coast Range

Forest Ecology and Management ◽

10.1016/j.foreco.2017.01.005 ◽

2017 ◽

Vol 389 ◽

pp. 285-295 ◽

Cited By ~ 9

Author(s):

Eladio H. Cornejo-Oviedo ◽

Steven L. Voelker ◽

Douglas B. Mainwaring ◽

Douglas A. Maguire ◽

Frederick C. Meinzer ◽

...

Keyword(s):

Water Use Efficiency ◽

Water Use ◽

Carbon Isotope Discrimination ◽

Basal Area ◽

Coast Range ◽

Oregon Coast Range ◽

Oregon Coast ◽

Intrinsic Water Use Efficiency ◽

Area Growth ◽

Use Efficiency

Download Full-text

Douglas-Fir Beetle Response to Artificial Creation of Down Wood in the Oregon Coast Range

Western Journal of Applied Forestry ◽

10.1093/wjaf/21.3.117 ◽

2006 ◽

Vol 21 (3) ◽

pp. 117-122 ◽

Cited By ~ 4

Author(s):

Darrell W. Ross ◽

Bruce B. Hostetler ◽

John Johansen

Keyword(s):

Tree Mortality ◽

Large Diameter ◽

Douglas Fir ◽

Coast Range ◽

Managed Forests ◽

Oregon Coast Range ◽

Oregon Coast ◽

Management Objectives ◽

Baited Traps ◽

Before And After

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.

Download Full-text

Relationship Between Occurrence of Laminated Root Rot and Site Characteristics in Douglas-Fir Forests of the Northern Oregon Coast Range

Western Journal of Applied Forestry ◽

10.1093/wjaf/9.1.14 ◽

1994 ◽

Vol 9 (1) ◽

pp. 14-17 ◽

Cited By ~ 1

Author(s):

Walter W. Kastner ◽

Donald J. Goheen ◽

Robert L. Edmonds

Keyword(s):

Root Rot ◽

Basal Area ◽

Douglas Fir ◽

Slope Position ◽

Coast Range ◽

Plant Association ◽

Oregon Coast Range ◽

Oregon Coast ◽

Disease Occurrence ◽

Site Characteristics

Abstract In the northern Oregon Coast Range 70- to 100-yr old Douglas-fir (Pseudotsuga menziesii) stands were evaluated to determine rate of infection by laminated root rot, caused by (Phellinus weirii), whether local disease occurrence was associated with site characteristics, and impacts of P. weirii on the number of trees and basal area. Overall infection rate was 5.6%, but varied from 0.0 to 14.7% among stands. There was a significant association between occurrence of P. weirii and slope position. The rate of infection on ridges, upper slopes, middle slopes, and lower slopes was 13.0, 7.3, 4.1, and 0.0%, respectively. Occurrence of P. weirii was independent of plant association and aspect. Infected plots contained 25% less live Douglas-fir basal area and 35% fewer live Douglas-fir trees per ac than uninfected plots. West. J. Appl. For. 9(1):14-17.

Download Full-text

Taper and Volume Responses of Douglas-Fir to Sulfur Treatments for Control of Swiss Needle Cast in the Coast Range of Oregon

Western Journal of Applied Forestry ◽

10.1093/wjaf/23.3.142 ◽

2008 ◽

Vol 23 (3) ◽

pp. 142-148 ◽

Cited By ~ 6

Author(s):

Nicole L. Younger ◽

Hailemariam Temesgen ◽

Sean M. Garber

Keyword(s):

Douglas Fir ◽

Coast Range ◽

Oregon Coast Range ◽

Sapwood Area ◽

Oregon Coast ◽

Needle Cast ◽

Crown Width ◽

Commercial Thinning ◽

Swiss Needle Cast ◽

And Control

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.

Download Full-text

Responses of Red Alder to Thinning

Western Journal of Applied Forestry ◽

10.1093/wjaf/10.1.17 ◽

1995 ◽

Vol 10 (1) ◽

pp. 17-23 ◽

Cited By ~ 5

Author(s):

David E. Hibbs ◽

William H. Emmingham ◽

Michael C. Bondi

Keyword(s):

Basal Area ◽

Height Growth ◽

Diameter Growth ◽

Alnus Rubra ◽

Coast Range ◽

Red Alder ◽

Oregon Coast Range ◽

Oregon Coast ◽

Basal Area Growth ◽

Area Growth

Abstract Responses of red alder (Alnus rubra Bong.) to thinning were observed at two sites in the Oregon Coast Range. Five years after thinning in the 20-yr-old stand, mortality was observed only in control plots. Diameter growth of crop trees increased up to 54% with thinning. Trends toward less height growth at wider spacings and increased growth in basal area compared to controls appeared to be developing in thinned plots. Ten years after thinning in the 14-yr-old stand, the problems of flashback seen at year 5 in the chemically thinned plots had largely been overcome. Reduction in height growth in all thinned plots had been overcome. Net basal area growth was up to 60% greater in thinned treatments. Thinning appears effective for 10 to 15 yr in the narrow spacings and 15 to 20 yr in the wide spacings. West. J. Appl. For. 10(1): 17-23.

Download Full-text