OBSERVATIONS ON THE BIOLOGY OF THE AMBROSIA BEETLE GNATHOTRICHUS RETUSUS (LECONTE) (COLEOPTERA: SCOLYTIDAE)

1993 ◽  
Vol 125 (1) ◽  
pp. 73-83 ◽  
Author(s):  
Yong-Biao Liu ◽  
John A. McLean
Keyword(s):  
Light Intensity ◽  
Douglas Fir ◽  
Ambrosia Beetle ◽  
Western Hemlock ◽  
Maximum Temperature ◽  
Major Peak ◽  
Brood Production ◽  
Small Peak ◽  
Large Peak ◽  
Over Time

AbstractThe ambrosia beetle Gnathotrichus retusus (LeConte) (Coleoptera: Scolytidae) is primarily univoltine. The development of brood from eggs to adult took a minimum of 40 days in Douglas-fir logs. Brood production was proportional to gallery length. Boring activities shifted from shallow sapwood to deep sapwood over time. Gallery abandonments were mainly made by females on warm days in June and July.Gnathotrichus retusus can use both Douglas-fir and western hemlock stumps equally well for brood production. Brood emergence began in late April, peaked in late May, and ceased, with rare exceptions, in late June. The seasonal flight began in late April and had one major peak in June, with occasional catches through October when the weekly mean maximum temperature dropped below 15 °C. Brood emergence, seasonal flight, and the sex ratios of captured beetles varied with temperature. Diurnal flight showed a small peak in morning and a large peak at dusk, probably entrained mainly by light intensity and also influenced by temperature and relative humidity.

REPRODUCTION AND SURVIVAL OF THE AMBROSIA BEETLE TRYPODENDRON LINEATUM (OLIV.) (COLEOPTERA: SCOLYTIDAE) IN DOUGLAS-FIR AND WESTERN HEMLOCK LOGS

1987 ◽  
Vol 119 (2) ◽  
pp. 131-139 ◽  
Author(s):  
T.L. Shore ◽  
J.A. McLean ◽  
J.C. Zanuncio
Keyword(s):  
Sex Ratio ◽  
Pseudotsuga Menziesii ◽  
Pupal Stage ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Flight Period ◽  
Trypodendron Lineatum ◽  
Brood Production ◽  
Linear Relationships

AbstractSpring-felled logs of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and western hemlock, Tsuga heterophylla (Raf.) Sarg., were attacked by ambrosia beetles, Trypodendron lineatum (Oliv.), in the year after felling. By monitoring individual galleries it was determined that brood production was similar to that found in fall- and winter-felled logs. The sex ratio of the brood did not differ significantly from 1:1. Only beetles that had failed to establish successful galleries emerged during the "second" flight period. Significant linear relationships were found between frass weight and each of the following variables: number of egg niches, emerged adult progeny, and gallery length. Mortality in galleries in Douglas-fir and western hemlock logs, respectively, was found to be 9.4 and 12.4% between the egg and larval–pupal stage and 19.5 and 32.1% between the larval–pupal and adult stages.

scholarly journals Ambrosia Beetles: A Multimillion Dollar Degrade Problem of Sawlogs in Coastal British Columbia

1985 ◽  
Vol 61 (4) ◽  
pp. 295-298 ◽  
Author(s):  
J. A. McLean
Keyword(s):  
British Columbia ◽  
Inventory Management ◽  
Douglas Fir ◽  
Ambrosia Beetle ◽  
Western Hemlock ◽  
Trypodendron Lineatum ◽  
Ambrosia Beetles ◽  
The Future ◽  
Coastal British Columbia

Ambrosia beetle degrade of sawlogs processed through the Vancouver log market in 1980/81 is calculated to be C$63.7 million. Similar losses can be expected in the future unless there are major changes in log inventory management. Gnathotrichus sulcatus was shown to penetrate Douglas-fir and western hemlock logs 3 cm and 8 cm respectively. The comparable figures for Trypodendron lineatum are 3 cm and 4 cm respectively. Factors that lead to the build up of ambrosia beetle populations in forest settings and processing areas must be identified to ensure maximum clearwood yield from logs.

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.

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.

Effects of exposure on water relations and photosynthesis of western hemlock in habitat forms

1976 ◽  
Vol 6 (1) ◽  
pp. 40-48 ◽  
Author(s):  
R. A. Keller ◽  
E. B. Tregunna
Keyword(s):  
Light Intensity ◽  
Water Content ◽  
Water Vapour ◽  
Western Hemlock ◽  
Diffusion Resistance ◽  
The Sun ◽  
Evaporative Demand ◽  
Photosynthetic Rates ◽  
Water Vapour Diffusion ◽  
Vapour Diffusion

Measurements of relative turgidity, transpiration rates, and photosynthetic rates on sun-grown and shade-grown western hemlock (Tsugaheterophylla (Raf.) Sarg.) were used to indicate effects of varying degrees of exposure.The sun-adapted form had low photosynthetic rates but maintained its water content under conditions of high evaporative demand. The shade-adapted form desiccated under exposed conditions, and in contrast with the sun-adapted form, its water vapour diffusion resistance decreased with increasing light intensity.

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.

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