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.

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

Diaporthe lokoyae n. sp., the perfect state of Phomopsis lokoyae

1968 ◽  
Vol 46 (5) ◽  
pp. 601-603 ◽  
Author(s):  
A. Funk
Keyword(s):  
New Species ◽  
Pseudotsuga Menziesii ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Perfect State ◽  
Ascigerous State ◽  
A New Species

A new species of Diaporthe, for which the name D. lokoyae Funk is proposed, is described on the host Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and in culture. This Diaporthe is shown to be the ascigerous state of Phomopsis lokoyae Hahn. An outbreak of dieback in Douglas fir associated with this Diaporthe is described and discussed; a single occurrence on western hemlock (Tsuga heterophylla (Raf.) Sarg.) is reported.

Multi-decadal establishment for single-cohort Douglas-fir forests

2014 ◽  
Vol 44 (9) ◽  
pp. 1068-1078 ◽  
Author(s):  
James A. Freund ◽  
Jerry F. Franklin ◽  
Andrew J. Larson ◽  
James A. Lutz
Keyword(s):  
Pseudotsuga Menziesii ◽  
Temporal Patterns ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Old Growth ◽  
Old Growth Forests ◽  
Western Washington ◽  
Century Development ◽  
Single Cohort

The rate at which trees regenerate following stand-replacing wildfire is an important but poorly understood process in the multi-century development of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) forests. Temporal patterns of Douglas-fir establishment reconstructed from old-growth forests (>450 year) have generated contradictory models of either rapid (<25 year) or prolonged (>100 year) periods of establishment, while patterns of tree establishment in mid-aged (100 to 350 year) forests remains largely unknown. To determine temporal patterns of Douglas-fir establishment following stand-replacing fire, increment cores were obtained from 1455 trees in 18 mature and early old-growth forests in western Washington and northwestern Oregon, USA. Each of the stands showed continuous regeneration of Douglas-fir for many decades following initiating fire. The establishment period averaged 60 years (range: 32–99 years). These results contrast both with the view of rapid (one- to two-decade) regeneration of Douglas-fir promoted in the early forestry literature and with reports of establishment periods exceeding 100 years in older (>400 year) Douglas-fir–western hemlock stands. These results have important implications for management designed to create and promote early-seral forest characteristics.

Crown profile equations for stand-grown western hemlock trees in northwestern Oregon

2003 ◽  
Vol 33 (11) ◽  
pp. 2059-2066 ◽  
Author(s):  
David D Marshall ◽  
Gregory P Johnson ◽  
David W Hann
Keyword(s):  
Pseudotsuga Menziesii ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Lower Portion ◽  
Data Set ◽  
Profile Model ◽  
Crown Width ◽  
Crown Form

Crown profile equations were developed for stand-grown western hemlock (Tsuga heterophylla (Raf.) Sarg.) in northwest Oregon. The profile model uses a segmented approach, dividing the crown into an upper and lower portion at the point of the largest crown width (LCW). The model explains about 86% of the variation in crown width when LCW is known but only 66% when LCW is predicted using a model developed from a larger data set collected in the same area as the data for developing the crown profile models were collected. The model can be adjusted using measurements or predictions of LCW for western hemlock in other populations. Comparisons are made with the crown form of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco).

A new Nitschkia on western conifers and its probable microconidial state

1979 ◽  
Vol 57 (20) ◽  
pp. 2113-2115 ◽  
Author(s):  
A. Funk
Keyword(s):  
British Columbia ◽  
New Species ◽  
Pseudotsuga Menziesii ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Coastal British Columbia ◽  
A New Species

A new species, Nitschkia molnarii (Ascomycetes: Nitschkiaceae), is described from Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) in coastal British Columbia, Canada. A microconidial state closely associated with the ascocarps is described, but not separately named.

LINEATIN ENANTIOMER PREFERENCE, FLIGHT PERIODS, AND EFFECT OF PHEROMONE CONCENTRATION AND TRAP LENGTH ON THREE SYMPATRIC SPECIES OF TRYPODENDRON (COLEOPTERA: SCOLYTIDAE)

2000 ◽  
Vol 132 (6) ◽  
pp. 877-887 ◽  
Author(s):  
B.S. Lindgren ◽  
S.E.R. Hoover ◽  
A.M. MacIsaac ◽  
C.I. Keeling ◽  
K.N. Slessor
Keyword(s):  
Sex Ratio ◽  
Reproductive Isolation ◽  
Release Rate ◽  
Sympatric Species ◽  
Ambrosia Beetle ◽  
Flight Period ◽  
Trypodendron Lineatum ◽  
Temporal Separation ◽  
Baited Traps ◽  
Pheromone Concentration

AbstractThe effects of lineatin enantiomer ratios, lineatin release rate, and trap length on catches and the flight periods of three sympatric species of Trypodendron Stephens were investigated in field bioassays using multiple-funnel traps. The ambrosia beetle, Trypodendron betulae Swaine, was caught in similar numbers in baited traps and blank control traps, showing that this species does not respond to lineatin. Our results confirmed that Trypodendron lineatum (Olivier) is attracted only to (+)-lineatin. Trypodendron rufitarsus (Kirby) and Trypodendron retusum (LeConte) were shown to utilize lineatin and like T. lineatum were caught only when (+)-lineatin was present. These results indicate that lineatin does not govern reproductive isolation among these three species. There was no effect by (+)-lineatin release rate within the range tested. The flight of T. rufitarsus commenced earlier and ceased before the peak of the T. lineatum flight, suggesting that temporal separation may be an important component of reproductive isolation between these two species. The flight period of T. retusum was similar to that of T. lineatum. Host odours may aid in reproductive isolation of these two species. Enantiomer blend did not significantly affect sex ratio in any species; however, sex ratio differed among species, indicating that different species responded differently to the traps or that natural sex ratios differ. Catches of T. rufitarsus and T. retusum increased with trap length when pheromone release per trap was held constant and when release was held constant relative to trap length. Trap length and release rate did not affect sex ratio.

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.

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.

scholarly journals Estimating the Number of Filled Seeds per Cone of Western Hemlock from Coastal British Columbia

1996 ◽  
Vol 11 (2) ◽  
pp. 44-49
Author(s):  
M. D. Meagher
Keyword(s):  
British Columbia ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Linear Relationships ◽  
The Face ◽  
Predetermined Level ◽  
Exponential Factors ◽  
The Relationship ◽  
Coastal British Columbia ◽  
Filled Seeds

Abstract Unopened western hemlock (Tsuga heterophylla) cones from coastal British Columbia were tested for the relationship between total filled seeds per cone and the number of sound seeds exposed by slicing through the center of the cone's long axis, and with cone length. Predictive linear relationships of total number of filled seeds per cone (TFS), based on number of filled seeds cut on the face through the cone's long axis (CC), were found in a cone sample bulked from a number of trees. The regression based on CC explained about 63% of the variation in TFS. More accurate estimates of TFS were found where cone length, and exponential factors of CC and cone length, were included in the analysis. Analyses of cones from seven parents did not find statistically significant trends of TFS on CC in all cases, and differed in slope in most cases. Sample sizes (cones) to estimate TFS to a predetermined level of precision were much larger than cones needed to accept or reject a tree for study. West. J. Appl. For. (11)2:44-49.

Comparing productivity of pure and mixed Douglas-fir and western hemlock plantations in the Pacific Northwest

2006 ◽  
Vol 36 (6) ◽  
pp. 1484-1496 ◽  
Author(s):  
M M Amoroso ◽  
E C Turnblom
Keyword(s):  
Pacific Northwest ◽  
Stand Density ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Western Hemlock ◽  
Mixed Stand ◽  
Mixed Stands ◽  
Individual Tree ◽  
The Pacific ◽  
Increase In Productivity

We studied pure and 50/50 mixtures of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and western hemlock (Tsuga heterophylla (Raf.) Sarg.) plantations to compare attained total yields between mixed-species stands as opposed to monocultures of equal densities. Whether overall stand density influences this outcome has not been adequately investigated, and to address this we included three density levels (494, 1111, and 1729 trees/ha) in the analysis. At age 12, as components of the mixed stands, Douglas-fir exhibited greater height, diameter, and individual-tree volume than western hemlock at all densities. At 494 and 1111 trees/ha the monocultures had a higher volume per hectare than the mixed stand, but at 1729 trees/ha the mixed stand appeared to be just as productive as the pure stands. The increase in productivity by the mixture at high densities seems to have resulted from the partial stratification observed and most likely also from better use of the site resources. Because of this, less interspecific competition was probably experienced in the mixed stand than intraspecific competition in the pure stands. This study shows the important role density plays in the productivity of mixed stands and thus in comparing mixed and pure stands.

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