scholarly journals Geographic variation in the seed mycobiome of Pseudotsuga menziesii var. menziesii across the Pacific Northwest, USA

2020 ◽  
Author(s):  
Gillian E. Bergmann ◽  
Posy E. Busby
Keyword(s):  
Abiotic Stress ◽  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Tree Species ◽  
Host Plants ◽  
Douglas Fir ◽  
Plant Tissues ◽  
The Pacific ◽  
Functional Consequences ◽  
Seedling Germination

ABSTRACTFungal symbionts occur in all plant tissues, and many aid their host plants with critical functions, including nutrient acquisition, defense against pathogens, and tolerance of abiotic stress. “Core” taxa in the plant mycobiome, defined as fungi present across individuals, populations, or time, may be particularly crucial to plant survival during the challenging seedling stage. However, studies on core seed fungi are limited to individual sampling sites, raising the question of whether core taxa exist across large geographic scales. We addressed this question using both culture-based and culture-free techniques to identify the fungi found in individual seeds collected from nine provenances across the range of Coastal Douglas-fir (Pseudotsuga menziesii var. menziesii), a foundation tree species in the Pacific Northwest and a globally important timber crop that is propagated commercially by seed. Two key findings emerged: 1) Seed mycobiome composition differed among seed provenances. 2) Despite spatial variation in the seed mycobiome, we detected four core members, none of which is a known pathogen of Douglas-fir: Trichoderma spp., Hormonema macrosporum, Mucor plumbeus and Talaromyces rugulosus. Our results support the concept of a core seed microbiome, yet additional work is needed to determine the functional consequences of core taxa for seedling germination, growth, survival and competition.

Soil and Douglas-fir (Pseudotsuga menziesii) foliar nitrogen responses to variable logging-debris retention and competing vegetation control in the Pacific Northwest

2010 ◽  
Vol 40 (2) ◽  
pp. 254-264 ◽  
Author(s):  
Robert A. Slesak ◽  
Timothy B. Harrington ◽  
Stephen H. Schoenholtz
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Soil N ◽  
Vegetation Control ◽  
Competing Vegetation ◽  
Total Soil ◽  
The Pacific ◽  
N Acquisition ◽  
Total Soil N

Experimental treatments of logging-debris retention (0%, 40%, or 80% surface coverage) and competing vegetation control (initial or annual applications) were installed at two sites in the Pacific Northwest following clearcutting Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) stands to assess short-term effects on tree N acquisition, soil N supply, and total soil N. Vegetation control treatments began in the first year after harvest, and logging-debris manipulations were installed 2 years after harvest. Annual vegetation control increased foliar N concentration and content in most years at both sites, which was associated with higher available soil N and increased soil water content. Logging-debris retention treatments had no detectable effect on any of the foliar variables or soil available N at either site. There were no treatment effects on total soil N at the site with relatively high soil N, but total soil N increased with logging-debris retention when annual vegetation control was applied at the site with a low initial soil N pool. Competing vegetation control is an effective means to increase tree N acquisition in the initial years after planting while maintaining soil N pools critical to soil quality. The effect of logging-debris retention on tree N acquisition appears to be limited during early years of stand development, but increased soil N with heavy debris retention at certain sites may be beneficial to tree growth in later years.

Characterization and classification of mycorrhizae of Douglas fir. II. Pseudotsuga menziesii + Rhizopogon vinicolor

1971 ◽  
Vol 49 (7) ◽  
pp. 1079-1084 ◽  
Author(s):  
B. Zak
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Phytophthora Cinnamomi ◽  
Pythium Ultimum ◽  
Douglas Fir ◽  
Root Pathogens ◽  
The Pacific ◽  
Pythium Sylvaticum ◽  
Thin Walled

A common tuberculate ectomycorrhiza of Douglas fir in the Pacific Northwest, described earlier by Trappe, is further examined and defined. Tubercles consist of an outer rind of aseptate, amber, thick-walled hyphae encasing tightly packed inner elements mantled with septate, hyaline, thin-walled hyphae. Reported as a Phycomycete and a Basidiomycete, respectively, the two hyphal forms actually belong to a single fungus, Rhizopogon vinicolor A. H. Smith; cultural characteristics of this fungus are described. Pure culture mycorrhiza syntheses with both mycorrhizal and sporocarpic isolates and Douglas-fir seedlings are reported. Antagonism tests revealed the following inhibition of root pathogens by R. vinicolor: strong—Phytophthora cinnamomi Rands, Pythium debaryanum Heese, and Pythium sylvaticum Campbell & Hendrix; moderate—Fomes annosus (Fr.) Cke. and Poria weirii Murr.; and weak or none— Fusarium oxysporum f. pini (Hartig) Snyd. & Hans., Pythium ultimum Trow, Rhizoctonia solani Kuehn, and Macrophomina phaseoli (Maubl.) Ashby.

Impact of stem lean on estimation of Douglas-fir (Pseudotsuga menziesii) diameter and volume using mobile lidar scans

2021 ◽  
Author(s):  
Cory Glenn Garms ◽  
Bogdan Strimbu
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Point Clouds ◽  
Douglas Fir ◽  
Stem Volume ◽  
Horizontal Distance ◽  
The Pacific ◽  
Commercial Species ◽  
The Impact ◽  
Volume Models

The value of Douglas-fir (Pseudotsuga menziesii), which is the predominant commercial species in the Pacific Northwest, depends on tree verticality; trees with same dimensions can differ substantially in value due to lean. The objective of this study was to assess the impact of tree leaning on estimation of stem dimensions using high density terrestrial mobile lidar point clouds. We estimated lean with two metrics: the horizontal distance between stem centers at 1.3m and 18m, and the mean of seven successive lean angles along the tree bole (at 1, 3, 5, 7, 10, 12, and 15m). For modeling, we used four existing taper equations and three existing volume equations. For trees leaning >2º, we enhanced the existing volume models by including lean as a predictor. Because lean estimates depend on the distribution and number of points describing the stem, we found that including the distance from scanner to tree improved the computed volume. When DBH was replaced with diameter at heights between 7 - 10m, the volume models for leaning trees improved significantly, whereas the vertical trees had favorable results with heights between 5-15m. Our study suggests the inclusion of lean magnitude improves estimates of stem volume when lean is >2°.

Invasive scotch broom alters soil chemical properties in Douglas-fir forests of the Pacific Northwest, USA

2015 ◽  
Vol 398 (1-2) ◽  
pp. 281-289 ◽  
Author(s):  
Robert A. Slesak ◽  
Timothy B. Harrington ◽  
Anthony W. D’Amato
Keyword(s):  
Pacific Northwest ◽  
Chemical Properties ◽  
Douglas Fir ◽  
Soil Chemical Properties ◽  
Scotch Broom ◽  
The Pacific

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.

Keepability of Pennsylvania versus West Coast Grown Douglas-Fir Christmas Trees: Genotypic Variation in Relation to Subfreezing Temperatures

1990 ◽  
Vol 7 (2) ◽  
pp. 86-89 ◽  
Author(s):  
Mark E. Kubiske ◽  
Marc D. Abrams ◽  
James C. Finley
Keyword(s):  
Pacific Northwest ◽  
Genotypic Variation ◽  
Rocky Mountain ◽  
Douglas Fir ◽  
Seed Sources ◽  
Christmas Trees ◽  
Display Area ◽  
The Pacific ◽  
Significant Difference ◽  
Needle Loss

Abstract Cut Douglas-fir Christmas trees grown in Pennsylvania from Rocky Mountain seed sources and coastal trees grown in the Pacific Northwest and shipped into Pennsylvania were compared for keepability. Following various cold treatments, the cut ends of trees were placed in water in an indoor display area. Coastal trees placed in a freezer at - 29°C for 24 h had 89 ± 5.1% (mean ± standard error) needle loss after one day of display, while Rocky Mountain origin trees exhibited only 3 ± 2.0% needle loss after 1 day and 50 ± 5.6% needle loss after 18 days. Coastal produced trees exposed to temperatures > - 12°C had 50 ± 9.8% needle loss at the end of the experiment, while Rocky Mountain trees ended with 22 ± 3.2% needle loss. Four additional treatments consisted of trees placed on an outdoor lot and periodically moved indoors to simulate Christmas tree market activity. Again, there was a significant difference between trees from coastal and Rocky Mountain sources, with 57.2 ± 4.3% and 11.8 ± 1.2% needle loss after 3 days, respectively. By the end of the 23 day experiment, the coastal trees were essentially devoid of needles, whereas Rocky Mountain trees had an average of only 20% needle loss. Coastal trees also exhibited a very noticeable loss of color and lustre. North. J. Appl. For. 7:86-89, June 1990.

scholarly journals Soil texture and other site-level factors differentially affect growth of Scotch broom (Cytisus scoparius) and Douglas-fir (Pseudotsuga menziesii) seedlings in the western Pacific Northwest

2021 ◽  
Author(s):  
David Carter ◽  
Robert A. Slesak ◽  
Timothy B. Harrington ◽  
Anthony W. D’Amato
Keyword(s):  
Pacific Northwest ◽  
Pseudotsuga Menziesii ◽  
Height Growth ◽  
Douglas Fir ◽  
Western Pacific ◽  
Limiting Factor ◽  
Cytisus Scoparius ◽  
Invasive Shrub ◽  
Scotch Broom ◽  
The Western Pacific

The invasive shrub Scotch broom (Cytisus scoparius (L.) Link) is a pervasive threat to regenerating Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) stands in the Pacific Northwest, USA. Field observations indicate that the susceptibility of areas to Scotch broom invasion and dominance can vary by site. We selected ten sites throughout the western Pacific Northwest that spanned a gradient of soil textures and other factors to test the site-specific susceptibility of Douglas-fir to overtopping by Scotch broom. We expected to find that the ability of Scotch broom to dominate a site was mediated by site-level factors, particularly those influencing soil water – the most limiting factor to growth in the region. We found Scotch broom and Douglas-fir were inversely affected by site-level factors. In general, Douglas-fir absolute height growth rates were more competitive with those of Scotch broom on fine-textured soils than on more coarsely textured soils. We also found Douglas-fir to have a more dramatic response to increasing down woody material than Scotch broom. Scotch broom height growth approached an asymptote at 3 m. Sites with fast-growing Douglas-fir were able to surpass this height six to seven years after planting and appear likely to avoid suppression by Scotch broom.

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