R-55 Rodent Repellent: Effect on Germination in Douglas-fir and Western Hemlock.

1972 ◽  
Vol 2 (3) ◽  
pp. 256-263 ◽  
Author(s):  
D. G. W. Edwards ◽  
Patricia E. Olsen
Keyword(s):  
Graphite Powder ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Repellent Effect ◽  
Dry Storage

Coating Douglas-fir and western hemlock seeds with R-55, a rodent repellent, seriously reduced normal germination. Acidifying the latex sticker, or adding graphite powder, had no effect. If seeds were coated first with latex, more R-55 could be applied without significantly increasing germination losses. Both stratification and dry storage of R-55 coated seeds increased germination losses. Treatment differences detected by normal germination percentages were also reflected in germination values. Observations based on total (normal + abnormal) germination obscured the effects of the various coatings.

THE 1951 AERIAL BAITING AND SEEDING PROJECT, ASH RIVER TRACT, MacMILLAN AND BLOEDEL LIMITED

1955 ◽  
Vol 31 (1) ◽  
pp. 45-59 ◽  
Author(s):  
G. S. Allen ◽  
I. K. Barber ◽  
Ian Mahood
Keyword(s):  
West Coast ◽  
Forest Service ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Local Distribution ◽  
Rodent Control ◽  
Buffer Strip ◽  
Minimum Standards ◽  
Service Standards ◽  
Forestry Practice

An area of 738 acres about 20 miles north and west of Port Alberni on Vancouver Island was seeded by helicopter to Douglas fir (1/2 pound per acre) and western hemlock (1/5 pound per acre) in November 1951. One week earlier this area and a surrounding buffer strip, totalling 1760 acres, had been baited by helicopter using wheat treated with thallous sulphate and "1080".Baiting was successful and the roden:trap ratio dropped from 1:4.6 to 1:94.3 as a result. By April the ratio had climbed again to 1:18.7. By the first week of June 1952, a total of about 1400 Douglas fir and 840 hemlock had germinated per acre. By November 1952, this had dropped to 1000 Douglas fir and 198 hemlock per acre. A final extensive survey in June 1954, showed a total of 730 Douglas fir and 57 hemlock of the 1952 crop per acre with a milacre stocking of 42.0 percent for Douglas fir and 43.9 percent for Douglas fir and hemlock. The 4-milacre stocking due to the 1952 Douglas fir seedlings was 78.3 percent. Practically all of the seedlings that germinated in 1952 are attributed to the seeding operation because of the relatively uniform distribution of seedlings and the lack of seedlings on the control area.The seeding operation in itself restocked 628 acres to B.C. Forest Service minimum standards (31 percent by 1-milacres). It restocked 708 acres to U.S. "medium" or "good" standards. With natural trees included, only 28 acres are below B.C. Forest Service standards, and 6 acres below U.S. "medium" stocking. Total stocking, including natural trees, is 59.3 percent by 1-milacres and 88.6 percent by 4-milacres.The baiting and seeding operation can be considered highly successful. The surviving Douglas firs are healthy and vigorous and show little deer or grouse damage to date. Distribution of the seedlings is good and most gaps that occurred are believed due to uneven local distribution of seed. Considering that this experiment was carried out on a rather steep south exposure and that the first summer following seeding was unusually hot and dry, the satisfactory results suggest that direct seeding following rodent control has a definite place in West Coast forestry practice. It may well take the place of more expensive and troublesome planting on many areas that are slow to restock.

Xenomeris Abietis Associated with Dieback of Douglas Fir and Western Hemlock

Mycologia ◽  
1971 ◽  
Vol 63 (3) ◽  
pp. 567-574 ◽  
Author(s):  
A. Funk ◽  
R. A. Shoemaker
Keyword(s):  
Douglas Fir ◽  
Western Hemlock

Growth ofPseudotsuga menziesiiandTsuga heterophyllaseedlings along a light gradient: resource allocation and morphological acclimation

1997 ◽  
Vol 75 (9) ◽  
pp. 1424-1435 ◽  
Author(s):  
D. Mailly ◽  
J. P. Kimmins
Keyword(s):  
Leaf Morphology ◽  
Biomass Accumulation ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Low Light ◽  
Growing Seasons ◽  
Light Levels ◽  
Light Gradient ◽  
Relative Light Intensity

Silvicultural alternatives that differ in the degree of overstory removal may create shady environments that will be problematic for the regeneration of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco). Gradients of light in the field were used to compare mortality, growth, and leaf morphological acclimation of two conifer species of contrasting shade tolerances: Douglas-fir and western hemlock (Tsuga heterophylla (Raf.) Sarg.). Results after two growing seasons indicated that Douglas-fir mortality occurred mainly at relative light intensity (RLI) below 20%, while western hemlock mortality was evenly distributed along the light gradient. Height, diameter, and biomass of the planted seedlings increased with increasing light for both species but at different rates, and maximum biomass accumulation always occurred in the open. Douglas-fir allocated more resources to stem biomass than western hemlock, which accumulated more foliage biomass. Increases in specific leaf area for Douglas-fir seedlings occurred at RLI ≤ 0.4 and red/far red (R/FR) ratio ≤ 0.6, which appear to be the minimal optimum light levels for growth. Conversely, western hemlock seedlings adjusted their leaf morphology in a more regular pattern, and changes were less pronounced at low light levels. These results, along with early mortality results for Douglas-fir, suggest that the most successful way to artificially regenerate this species may be by allowing at least 20% of RLI for ensuring survival and at least 40% RLI for optimum growth. Key words: light, light quality, leaf morphology, acclimation.

Survival dynamics of mechanically topped Douglas-fir (Pseudotsuga menziesii) and western hemlock (Tsuga heterophylla) snags in Douglas-fir plantations, Oregon, USA

2019 ◽  
Vol 433 ◽  
pp. 105-110
Author(s):  
Matthew E. Hane ◽  
Andrew J. Kroll ◽  
Aaron Springford ◽  
Jack Giovanini ◽  
Mike Rochelle ◽  
...  
Keyword(s):  
Pseudotsuga Menziesii ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock

Canopy disturbances over the five-century lifetime of an old-growth Douglas-fir stand in the Pacific Northwest

2002 ◽  
Vol 32 (6) ◽  
pp. 1057-1070 ◽  
Author(s):  
Linda E Winter ◽  
Linda B Brubaker ◽  
Jerry F Franklin ◽  
Eric A Miller ◽  
Donald Q DeWitt
Keyword(s):  
Pacific Northwest ◽  
Variable Density ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Old Growth ◽  
The Pacific ◽  
History Of ◽  
Horizontal Heterogeneity ◽  
Restoration Strategies

The history of canopy disturbances over the lifetime of an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) stand in the western Cascade Range of southern Washington was reconstructed using tree-ring records of cross-dated samples from a 3.3-ha mapped plot. The reconstruction detected pulses in which many western hemlock (Tsuga heterophylla (Raf.) Sarg.) synchronously experienced abrupt and sustained increases in ringwidth, i.e., "growth-increases", and focused on medium-sized or larger ([Formula: see text]0.8 ha) events. The results show that the stand experienced at least three canopy disturbances that each thinned, but did not clear, the canopy over areas [Formula: see text]0.8 ha, occurring approximately in the late 1500s, the 1760s, and the 1930s. None of these promoted regeneration of the shade-intolerant Douglas-fir, all of which established 1500–1521. The disturbances may have promoted regeneration of western hemlock, but their strongest effect on tree dynamics was to elicit western hemlock growth-increases. Canopy disturbances are known to create patchiness, or horizontal heterogeneity, an important characteristic of old-growth forests. This reconstructed history provides one model for restoration strategies to create horizontal heterogeneity in young Douglas-fir stands, for example, by suggesting sizes of areas to thin in variable-density thinnings.

Stump colonization and spread of Fomesannosus 5 years after thinning

1978 ◽  
Vol 8 (2) ◽  
pp. 177-180 ◽  
Author(s):  
D. J. Morrison ◽  
A. L. S. Johnson
Keyword(s):  
Douglas Fir ◽  
Western Hemlock ◽  
Primary Roots

Plots were thinned each month for 1 year in a Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantation and western hemlock (Tsugaheterophylla (Raf.) Sarg.) stand. Stumps colonized by Fomesannosus (Fr.) Karst. declined from an average of 82% in Douglas-fir and 62% in hemlock, 6 months after thinning, to 4 and 9%, respectively, 5 years after thinning. In 7 Douglas-fir and 14 hemlock stumps, F. annosus had colonized one or more primary roots and the stumps were a source of inoculum for new infection centers. The thinning, which removed about 25% of the stems, potentially doubled the number of F. annosus infection centers.

ATTACK BY GNATHOTRICHUS SULCATUS (COLEOPTERA: SCOLYTIDAE) ON STUMPS AND FELLED TREES BAITED WITH SULCATOL AND ETHANOL

1977 ◽  
Vol 109 (5) ◽  
pp. 675-686 ◽  
Author(s):  
J. A. McLean ◽  
J. H. Borden
Keyword(s):  
Bark Beetles ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Systemic Insecticide ◽  
Dendroctonus Pseudotsugae ◽  
University Of British Columbia ◽  
Steady Decrease ◽  
Population Aggregation ◽  
The University

AbstractEthanol and sulcatol (6-methyl-5-hepten-2-ol), primary attractant and population aggregation pheromone, respectively, for Gnathotrichus sulcatus, were deployed alone or in combination on stumps and felled trees in the University of British Columbia Research Forest, Maple Ridge, B.C. On 18 April 1974, four Douglas-fir trees were felled at each of three locations, and four western hemlock trees were felled at each of three other locations. Felled trees and their respective stumps were baited on 26 April. Attacks by G. sulcatus and bark beetles were recorded at weekly intervals until 25 October. G. sulcatus attacks increased rapidly, reaching a maximum in June and July, followed by a steady decrease to October. Attacks by Dendroctonus pseudotsugae, Pseudohylesinus nebulosus, and P. tsugae showed characteristic seasonal trends, but were not correlated to any of the treatments. Over half the G. sulcatus attacks were on stumps, in which attack densities reached 683.5/m2. The greatest numbers of attacks were on stumps and logs baited with sulcatol or sulcatol plus ethanol. There was a significant interaction between sulcatol and ethanol on Douglas-fir but not on western hemlock. Significantly more G. sulcatus attacked ethanol-baited western hemlock stumps and logs than unbaited controls. However, there was no difference between the level of attack on ethanol-baited Douglas-fir and the controls. The role of ethanol is hypothesized to be more of a boring stimulant than a major attractant. Stumps baited with sulcatol and then treated with ethanolic solutions of systemic insecticide could be used to trap and kill field populations, thus reducing numbers of G. sulcatus being transported to log-booming grounds, dryland sorting areas, and sawmills.

Needle water potential and soil-to-foliage flow resistance during soil drying: a comparison of Douglas-fir, western hemlock, and mountain hemlock

1985 ◽  
Vol 15 (1) ◽  
pp. 185-188 ◽  
Author(s):  
T. M. Ballard ◽  
M. G. Dosskey
Keyword(s):  
Water Potential ◽  
Soil Water ◽  
Water Flow ◽  
Flow Resistance ◽  
Soil Water Potential ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Soil Drying ◽  
Experimental Conditions ◽  
Needle Water Potential

Needle water potential in western and mountain hemlock falls as the soil dries, but under our experimental conditions, it remained stable in Douglas-fir. Resistance to water flow from soil to foliage is higher for the hemlocks and increases more steeply as the soil dries. These findings physically account for the observation that water uptake is reduced relatively more for the hemlocks than for Douglas-fir, as soil water potential declines.

scholarly journals Optimizing Surface Micro Grooving to Reduce the Checking and Cupping of Douglas Fir, Western Hemlock and White Spruce Decking Exposed to Natural Weathering

2018 ◽  
Vol 2 (4) ◽  
pp. 67 ◽  
Author(s):  
Sina Heshmati ◽  
Mohammad Mazloomi ◽  
Philip Evans
Keyword(s):  
Numerical Model ◽  
White Spruce ◽  
Groove Depth ◽  
Douglas Fir ◽  
The Other ◽  
Western Hemlock ◽  
Natural Weathering ◽  
Micro Grooving ◽  
Induced Stresses

Machining grooves into the surface of pine and fir (Abies spp.) deckboards reduces undesirable checking that develops when “profiled” boards are exposed to the weather. We aim to develop improved profiles for Douglas fir, western hemlock and white spruce decking to reduce their susceptibility to checking, and understand how profile geometry influences the stresses that cause checking. We varied the width and depth of grooves in profiled deckboards, exposed deckboards to the weather, and measured checking and cupping of boards. A numerical model examined the effect of groove depth on the moisture-induced stresses in profiled spruce boards. Profiling significantly reduced checking, but increased cupping of deckboards made from all three species. Western hemlock checked more than the other two species. Profiles with narrow grooves (rib profiles) were better at restricting checking than profiles with wider grooves. A rib profile with deeper grooves developed smaller stresses than a rib profile with shallower grooves, and boards with the former profile checked less than boards with shallower grooves. We conclude that checking of profiled Douglas fir, western hemlock and white spruce decking is significantly reduced by changing profile geometry, and our results suggest the best profiles to reduce checking of all three species.

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