Effects of variable-density thinning on non-native understory plants in coniferous forests of the Pacific Northwest

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 15001521. 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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EDGE-RELATED RESPONSES OF UNDERSTORY PLANTS TO AGGREGATED RETENTION HARVEST IN THE PACIFIC NORTHWEST

Ecological Applications ◽

10.1890/03-6002 ◽

2005 ◽

Vol 15 (1) ◽

pp. 196-209 ◽

Cited By ~ 54

Author(s):

Cara R. Nelson ◽

Charles B. Halpern

Keyword(s):

Pacific Northwest ◽

Understory Plants ◽

The Pacific ◽

Aggregated Retention

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Spatial distribution of ectomycorrhizal mats in coniferous forests of the Pacific Northwest, USA

Plant and Soil ◽

10.1007/bf00015421 ◽

1996 ◽

Vol 180 (1) ◽

pp. 147-158 ◽

Cited By ~ 28

Author(s):

Robert P. Griffiths ◽

Gay A. Bradshaw ◽

Barbara Marks ◽

George W. Lienkaemper

Keyword(s):

Spatial Distribution ◽

Pacific Northwest ◽

Coniferous Forests ◽

The Pacific

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Evergreen Coniferous Forests of the Pacific Northwest

Science ◽

10.1126/science.204.4400.1380 ◽

1979 ◽

Vol 204 (4400) ◽

pp. 1380-1386 ◽

Cited By ~ 356

Author(s):

R. H. Waring ◽

J. F. Franklin

Keyword(s):

Pacific Northwest ◽

Coniferous Forests ◽

The Pacific

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Tardigrades in the Canopy: Associations with Tree Vole Nests in Southwest Oregon

10.32942/osf.io/xvcuf ◽

2020 ◽

Author(s):

John Villella ◽

Jesse E. D. Miller ◽

Alexander Young ◽

Greg Carey ◽

Andrew Emanuels ◽

...

Keyword(s):

Pacific Northwest ◽

Environmental Variables ◽

Forest Canopy ◽

Coniferous Forests ◽

Forest Canopies ◽

Species Numbers ◽

The Pacific ◽

Southwest Oregon ◽

East West ◽

Local Dispersal

Tardigrades live in many ecosystems, but local dispersal mechanisms and the influence of ecological gradients on tardigrade communities are not fully understood. Here we examine tardigrade communities in nests of the red tree vole (Arborimus longicaudus True), an arboreal mammal occupying the canopy of coniferous forests in western Oregon and northwestern California. We found 12 species of tardigrades from resin ducts sampled from 43 nests along a transect that spanned the east-west range of the tree vole in southern Oregon. Tardigrade occurrence was more likely in larger trees and species numbers were significantly higher in areas that received more precipitation. At sites where they occurred, tardigrades were more abundant in tree vole nests at greater heights within the forest canopy. Of the 12 species of tardigrades that were found, seven have not been previously reported in Oregon. Our results suggest that tardigrades in forest canopies in the Pacific Northwest are impacted by regional precipitation gradients as well as local environmental variables, and that nest building by small mammals may facilitate dispersal of tardigrades within the forest canopy.

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