Site-Specific Douglas-Fir Biomass Equations from the Siskiyou Mountains, Oregon, Compared with Others from 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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Keepability of Pennsylvania versus West Coast Grown Douglas-Fir Christmas Trees: Genotypic Variation in Relation to Subfreezing Temperatures

Northern Journal of Applied Forestry ◽

10.1093/njaf/7.2.86 ◽

1990 ◽

Vol 7 (2) ◽

pp. 86-89 ◽

Cited By ~ 3

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.

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Soil phosphorus fractions vary with harvest intensity and vegetation control at two contrasting Douglas-fir sites in the Pacific northwest

Geoderma ◽

10.1016/j.geoderma.2019.04.038 ◽

2019 ◽

Vol 350 ◽

pp. 73-83 ◽

Cited By ~ 1

Author(s):

Daniel G. DeBruler ◽

Stephen H. Schoenholtz ◽

Robert A. Slesak ◽

Brian D. Strahm ◽

Timothy B. Harrington

Keyword(s):

Pacific Northwest ◽

Soil Phosphorus ◽

Douglas Fir ◽

Phosphorus Fractions ◽

Vegetation Control ◽

Soil Phosphorus Fractions ◽

Harvest Intensity ◽

The Pacific

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Astrosclereids In Needles Of Old-Growth Douglas-Fir Trees

Microscopy and Microanalysis ◽

10.1017/s1431927600019528 ◽

1999 ◽

Vol 5 (S2) ◽

pp. 1240-1241

Author(s):

M. Apple ◽

A. Soeldner ◽

R. Hamill ◽

K. Tiekotfer

Keyword(s):

Pacific Northwest ◽

Cell Walls ◽

Douglas Fir ◽

Old Growth ◽

Mesophyll Cells ◽

Mesophyll Tissue ◽

The Pacific ◽

And Function ◽

Development Structure

Old-growth Douglas-fir trees in the Pacific Northwest are venerable giants that often live for 500 years and reach heights of over 75 meters. Their needles are relatively ephemeral and small but have the important role of interacting with the atmosphere in order to transpire and photosynthesize. Within the photosynthetic mesophyll tissue of Douglas-fir needles, there are large, non-living cells with lignified secondary cell walls that are known as astrosclereids. Apparent channels in the secondary wall may provide a route for exchange or transport of materials between the astrosclereid lumen and mesophyll cells or the vascular cylinder. Astrosclereids may be involvev d in storage of secondary metabolites such as tannin and may develop in response to fungi, mistletoe, or other pathogens. More knowledge is needed about the development, structure and function of astrosclereids.Needles were collected from sapling and old-growth Douglas-fir, Pseudotsuga menziesii, (Mirb.) Franco, trees at the Wind River Canopy Crane in Carson, Washington and from three sites in the Cascade Mountains of Oregon in 1997 and 1998.

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

Canadian Journal of Forest Research ◽

10.1139/x06-042 ◽

2006 ◽

Vol 36 (6) ◽

pp. 1484-1496 ◽

Cited By ~ 61

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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