Impact of Nitrogen Fertilization on Forest Carbon Sequestration and Water Loss in a Chronosequence of Three Douglas-Fir Stands in 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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Forest Carbon Sequestration and Global Change

The Paradigm of Forests and the Survival of the Fittest ◽

10.1201/9781315367170-3 ◽

2018 ◽

pp. 39-86

Author(s):

Achim Häger ◽

Luitgard Schwendenmann

Keyword(s):

Carbon Sequestration ◽

Global Change ◽

Forest Carbon ◽

Forest Carbon Sequestration

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