scholarly journals Comparative Susceptibility of Conifers to Western Hemlock Dwarf Mistletoe in the Cascade Mountains of Washington and Oregon

2005 ◽  
Vol 20 (2) ◽  
pp. 94-100 ◽  
Author(s):  
Robert L. Mathiasen ◽  
Carolyn M. Daugherty
Keyword(s):  
Pacific Northwest ◽  
Tsuga Heterophylla ◽  
Host Susceptibility ◽  
Western Hemlock ◽  
Silver Fir ◽  
Mixed Conifer ◽  
Dwarf Mistletoe ◽  
Resource Managers ◽  
Abies Procera ◽  
Live Tree

Abstract A total of 24 mixed conifer stands in Washington and Oregon infested with western hemlock dwarf mistletoe (Arceuthobium tsugense subsp. tsugense) were sampled to compare host susceptibility to this parasitic plant. Temporary circular plots were established around dominant, severely infected western hemlocks (Tsuga heterophylla). Within plots, species, diameter at breast height, and dwarf mistletoe rating (6-class system) were determined for each live tree. More than 5,700 trees were sampled in 275 plots. Based on the incidence of infection, tree species were assigned to host susceptibility classes. Western hemlock is classified as the only principal host of western hemlock dwarf mistletoe. Pacific silver fir (Abies amabilis), noble fir (Abies procera), and mountain hemlock (Tsuga mertensiana) are classified as occasional hosts. Resource managers can use the host susceptibility classifications based on this study for decisions regarding which trees to retain when selectively harvesting mixed conifer stands infested with western hemlock dwarf mistletoe in the Pacific Northwest. West. J. Appl. For. 20(2):94–100.

scholarly journals Susceptibility of Conifers to Three Dwarf Mistletoes in the Klamath-Siskiyou Mountains

2011 ◽  
Vol 26 (1) ◽  
pp. 13-18 ◽  
Author(s):  
Robert Mathiasen
Keyword(s):  
Host Susceptibility ◽  
Mixed Conifer ◽  
White Pine ◽  
Dwarf Mistletoe ◽  
Susceptibility Data ◽  
Mixed Conifer Forests ◽  
Western White Pine ◽  
Siskiyou Mountains ◽  
Study Sites ◽  
Live Tree

Abstract Dwarf mistletoes (Arceuthobium spp., Viscaceae) are parasitic flowering plants that infect members of the Pinaceae family in the western United States. This article reports additional host susceptibility data for three dwarf mistletoes found in the Klamath-Siskiyou Mountains of southwestern Oregon and northwestern California. Three mixed conifer stands, each infested with either mountain hemlock dwarf mistletoe, western white pine dwarf mistletoe, or Wiens' dwarf mistletoe (nine stands total) were sampled to evaluate the susceptibility of conifers to these parasites. At each of the study sites, 10–20 temporary circular plots with a 6-m radius (0.012 ha) were established around large, severely infected trees. Within plots, species, dbh, and dwarf mistletoe rating (six-class system) were determined for each live tree. On the basis of the incidence of infection, conifers were assigned to host susceptibility classes. Western white pine and mountain hemlock were principal hosts of western white pine and mountain hemlock dwarf mistletoes, respectively. Brewer spruce and red fir were principal hosts of Wiens' dwarf mistletoe. Other conifers sampled were less susceptible to these mistletoes. This information can be used by forest managers to mitigate the damage associated with infestations of these dwarf mistletoes in mixed conifer forests of the Klamath-Siskiyou Mountains.

Spatial and population characteristics of dwarf mistletoe infected trees in an old-growth Douglas-fir – western hemlock forest

2005 ◽  
Vol 35 (4) ◽  
pp. 990-1001 ◽  
Author(s):  
David C Shaw ◽  
Jiquan Chen ◽  
Elizabeth A Freeman ◽  
David M Braun
Keyword(s):  
Nearest Neighbor ◽  
Positive Association ◽  
Tsuga Heterophylla ◽  
Douglas Fir ◽  
Negative Association ◽  
Population Characteristics ◽  
Western Hemlock ◽  
Silver Fir ◽  
Dwarf Mistletoe ◽  
Old Growth

We investigated the distribution and severity of trees infected with western hemlock dwarf mistletoe (Arceuthobium tsugense (Rosendahl) G.N. Jones subsp. tsugense) in an old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) – western hemlock (Tsuga heterophylla (Raf.) Sarg.) forest. With the use of Hawksworth six-class dwarf mistletoe rating system, infection status was assessed for 3516 hemlock and true firs ≥5 cm diameter on a 12-ha stem-mapped plot located in the Cascade Mountains of southwest Washington State. Within the plot, 33% of the area had some level of infection and 25% (719) of western hemlocks, 2.2% (12) of Pacific silver fir (Abies amabilis (Dougl.) Forbes), and 29% (2) of noble fir (Abies procera Rehd.) trees were infected. Infected trees are larger than uninfected trees, on average, and within the infected tree population, the severely infected trees averaged larger than lightly infected trees. Abundant dwarf mistletoe in larger trees definitely positions the dwarf mistletoe population for future spread. Ripley's K analysis indicates a negative association between infected and uninfected hemlock trees, confirming that the infected trees form distinct dwarf mistletoe infection centers. The infection centers are actively spreading at their margins, which was confirmed by nearest neighbor analysis. Heavily infected trees had a negative association with uninfected trees, while lightly infected trees had a positive association with uninfected trees.

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.

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.

Systematics and ecology of Anachipteria geminus sp. nov. (Acari: Oribatida: Achipteriidae) from arboreal lichens in western North America

2008 ◽  
Vol 140 (5) ◽  
pp. 539-556 ◽  
Author(s):  
Zoë Lindo ◽  
Marilyn Clayton ◽  
Valerie M. Behan-Pelletier
Keyword(s):  
North America ◽  
Pacific Northwest ◽  
Sequence Data ◽  
Oribatid Mite ◽  
Dry Mass ◽  
Tsuga Heterophylla ◽  
Silver Fir ◽  
28S Rrna ◽  
Molecular Sequence Data ◽  
The Family

AbstractWe present the systematics and ecology of a new species of arboreal oribatid mite in the family Achipteriidae, Anachipteria geminussp. nov., a dominant arthropod in canopy lichens associated with western hemlock (Tsuga heterophylla (Raf.) Sarg. (Pinaceae)) and Pacific silver fir (Abies amabilis (Dougl. ex Loud.) Dougl. ex Forbes (Pinaceae)) in the coniferous temperate and montane forests of the Pacific Northwest of North America. The species is described on the basis of the morphology of all active instars plus molecular sequence data for the D3 region of the 28s rRNA (D3-28s) and mitochondrial cytochrome oxidase 1 (CO1) genes. Anachipteria geminus is the dominant oribatid mite in foliose lichens in the upper canopies of Pacific montane conifer trees. Specimens were found in 100% of canopy lichens sampled, and abundances can reach 1450 individuals / 100 g dry mass of lichen. Analysis of the population structure indicates that A. geminus has seasonally stable populations consistent with overlapping generations. Anachipteria geminus expresses morphological character states that require expanding the diagnoses of the genus Anachipteria and the family Achipteriidae. A revised diagnosis and morphological key to species of Anachipteria in Canada are given.

New species of the genus Camisia (Acari: Oribatida): an arboreal mite with enclosed sensilli

2002 ◽  
Vol 134 (6) ◽  
pp. 707-721 ◽  
Author(s):  
Z. Olszanowski ◽  
M.R. Clayton ◽  
L.M. Humble
Keyword(s):  
Parallel Evolution ◽  
Oribatid Mite ◽  
Sister Group ◽  
High Elevation ◽  
Tsuga Heterophylla ◽  
Western Hemlock ◽  
Sister Group Relationship ◽  
Silver Fir ◽  
Coastal Forests ◽  
Distinctive Structure

AbstractA new oribatid mite (Acari), Camisia abdosensillasp.nov., is described from all instars, based on specimens from British Columbia, Canada. This species occurs on branches and foliose lichens in the canopies of western hemlock, Tsuga heterophylla (Raf.) Sarg., 1898 (Pinaceae), and Pacific silver fir, Abies amabilis (Dougl. ex Loud.) Dougl. ex J. Forbes, 1939 (Pinaceae), growing in high elevation coastal forests. The most unusual feature of this species is the distinctive structure of the prodorsal trichobothrium in adults; the significantly reduced sensillus is completely enclosed within the bothridium. A resemblance between the structure of this organ and those of the superfamily Crotonioidea appears to have resulted from parallel evolution rather than being evidence of a sister-group relationship. Another species, Camisia islandica Gjelstrup and Solhøy, 1994, is herein recognized as a junior synonym of Camisia solhoeyi Colloff, 1993. A key of the Nearctic species of the genus Camisia is given.

Systematics and ecology of the genus Dendrozetes (Acari: Oribatida: Peloppiidae) from arboreal habitats in Western North America

Zootaxa ◽  
2010 ◽  
Vol 2403 (1) ◽  
pp. 10 ◽  
Author(s):  
ZOE LINDO ◽  
MARILYN CLAYTON ◽  
VALERIE BEHAN-PELLETIER
Keyword(s):  
North America ◽  
Pacific Northwest ◽  
Sequence Data ◽  
Oribatid Mite ◽  
First Record ◽  
Tsuga Heterophylla ◽  
Coi Gene ◽  
Silver Fir ◽  
Type Specimens ◽  
Molecular Sequence Data

We present the systematics and ecology of a new species of arboreal oribatid mite in the family Peloppiidae (Acari: Oribatida), Dendrozetes jordani n. sp., a dominant arthropod on branch tips and arboreal lichens associated with western hemlock (Tsuga heterophylla (Pinaceae)) and Pacific silver fir (Abies amabilis (Pinaceae)) in the coniferous temperate and montane forests of the Pacific Northwest of North America. Dendrozetes jordani represents the first record of the genus Dendrozetes in North America. The species is described on the basis of morphology of all active instars plus molecular sequence data for the mitochondrial cytochrome oxidase I (COI) gene. Dendrozetes jordani is compared with type specimens of D. caudatus Aoki from Japan, and a revised diagnosis of the genus Dendrozetes is given. Dendrozetes jordani has a stable, overlapping population structure through the year, and its association with trees in Pinaceae is an ecological characteristic shared with D. caudatus from Japan.

scholarly journals Black Bear Damage to Forest Stands in Western Washington

1999 ◽  
Vol 14 (3) ◽  
pp. 128-131 ◽  
Author(s):  
William B. Stewart ◽  
Gary W. Witmer ◽  
Gary M. Koehler
Keyword(s):  
Pacific Northwest ◽  
Canopy Cover ◽  
Black Bear ◽  
Tsuga Heterophylla ◽  
Stand Age ◽  
Silver Fir ◽  
Forest Stands ◽  
Animal Damage ◽  
Western Washington ◽  
Natural Resource Managers

Abstract Cambium-feeding behavior by black bears (Ursus americanus), or bear damage, is a major reforestation problem in the Pacific Northwest. Historically, studies have measured the cumulative effects of damage over time, but few have viewed damage in the frame of one season. Bear damage occurring in 1996 was surveyed in areas of radio-marked bears in western Washington. Fresh damage occurred on 48% of bear location plots (n = 96). Douglas-fir (Pseudotsuga menziesii) (69%), western hemlock (Tsuga heterophylla) (19%), and Pacific silver fir (Abies amabilis) (10%) with a mean dbh of 25.1, 29.5, and 30.7 cm, respectively, were most frequently damaged. Random plots were surveyed from mid-July to mid-August to measure habitat availability. Stand and site variables were measured on freshly damaged bear location plots, random plots, and nondamaged bear location plots. This study identified several variables that make forest stands vulnerable to bear damage: conifer dbh, conifer density, stand age, and canopy cover. Awareness of such stand characteristics can assist natural resource managers with animal damage prevention and control programs. West. J. Appl. For. 14(3):128-131.

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