Thinning of young Douglas-fir forests decreases density of northern flying squirrels in the Oregon Cascades

We described trapping mortality rates of northern flying squirrel (Glaucomys sabrinus) populations in western Oregon, U.S.A., and evaluated the effects of sex, age, body mass, and number of times an individual was recaptured on these rates. Although the overall trapping mortality rates were relatively low (7%) during 16–21 day trapping sessions, we observed differential mortality rates among the sex and age cohorts. The order of mortality rates was: juvenile females (32.3%) > juvenile males (11.1%) > adult females (5.1%) = adult males (4.1%). Overall trapping mortality rates were not affected by the number of times an individual was captured. We hypothesize that the differences we found were due to extrinsic factors (weather-related) acting on differential behavioral responses to trapping and thresholds of stress an animal can tolerate.

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Evaluation of the provenance plot “Hrubá Skála” (Northern Bohemia) with grand fir at the age of 36 years

Journal of Forest Science ◽

10.17221/79/2016-jfs ◽

2017 ◽

Vol 63 (No. 2) ◽

pp. 75-87 ◽

Cited By ~ 1

Author(s):

Fulín Martin ◽

Novotný Petr ◽

Podrázský Vilém ◽

Beran František ◽

Dostál Jaroslav ◽

...

Keyword(s):

Czech Republic ◽

Norway Spruce ◽

Coastal Region ◽

Tree Height ◽

Douglas Fir ◽

Stem Volume ◽

Silver Fir ◽

The Czech Republic ◽

The North ◽

Oregon Cascades

The article aims to evaluate the research provenance plot established in 1980 in locality No. 214 – Hrubá Skála (in the north of the Czech Republic), where nine provenances of grand fir (Abies grandis (Douglas ex D. Don) Lindley) provided in the framework of the International Union of Forest Research Organizations project, and one provenance of grand fir, Norway spruce, silver fir and Douglas-fir from a standard commercial source are tested. We present the results of tree height, stem DBH, stem volume production and health status after 36 years. The results correspond with similar experiments in the Czech Republic and abroad and suggest that grand fir provenances from Vancouver Island (British Columbia, Canada) and the Washington (USA) State coastal region show the best production features, while the Oregon Cascades, Idaho and Montana provenances grow more slowly. Comparison with other tree species indicates that the production of grand fir at the investigated age exceeds the production of both Norway spruce and silver fir, and equalizes or gently exceeds even Douglas-fir.

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Response of aboveground biomass increment, growth efficiency, and foliar nutrients to thinning, fertilization, and pruning in young Douglas-fir plantations in the central Oregon Cascades

Canadian Journal of Forest Research ◽

10.1139/x92-170 ◽

1992 ◽

Vol 22 (9) ◽

pp. 1278-1289 ◽

Cited By ~ 37

Author(s):

Alejandro Velazquez-Martinez ◽

David A. Perry ◽

Tom E. Bell

Keyword(s):

Leaf Area ◽

Aboveground Biomass ◽

Cultural Practices ◽

Growth Efficiency ◽

Douglas Fir ◽

Nitrogen And Phosphorus ◽

Area Index ◽

Biomass Increment ◽

Oregon Cascades

The effect of thinning and cultural practices (multinutrient fertilization, pruning) on total aboveground biomass increment and growth efficiency was studied over three consecutive 2-year periods (1981–1987) in young Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) plantations. Net aboveground biomass increment over the 6-year period averaged 14.5, 7.8, and 5.5 Mg•ha−1•year−1 for the high-, medium-, and low-density plots, respectively. Growth efficiency, after dropping sharply between leaf area indexes of 1 and 6 m2/m2, remained relatively constant up to a leaf area index of 17, the highest measured. Consequently, aboveground biomass increment continued to increase at leaf area indexes well above that at which the Beer–Lambert law predicts maximum light should be absorbed. Foliage analyses indicate that thinning improved nitrogen, potassium, and magnesium nutrition and increased the translocation of potassium from 1-year-old foliage to support new growth. However, fertilization increased foliar nitrogen and phosphorus contents only when coupled with pruning, suggesting that trees favor total leaf area over individual needle nutrition. Indications of potassium and magnesium limitations in this study are supported by other recent studies in Douglas-fir. Further work on the role of multinutrient deficiencies in this species is warranted.

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Early Realized Genetic Gains for Coastal Douglas-Fir in the Northern Oregon Cascades

Western Journal of Applied Forestry ◽

10.1093/wjaf/19.3.195 ◽

2004 ◽

Vol 19 (3) ◽

pp. 195-201 ◽

Cited By ~ 12

Author(s):

J. Bradley St. Clair ◽

Nancy L. Mandel ◽

Keith J. S. Jayawickrama

Keyword(s):

Douglas Fir ◽

Stem Volume ◽

Early Assessment ◽

Improvement Program ◽

Genetic Gains ◽

Large Numbers ◽

Genetically Improved ◽

Progeny Tests ◽

Realized Genetic Gains ◽

Oregon Cascades

Abstract Block-plot realized genetic gain trials were established for coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) at five sites in the northern Oregon Cascades. The long-term objectives of these trials are to explore the growth trajectories and productivity of genetically improved stands and their relationship to predicted genetic gains based on performance in progeny tests. Measurements 5 years after planting provide an opportunity for an early assessment of realized genetic gains as compared to predicted gains and provide data for determining the number of replicates needed to detect statistically significant differences between improved and unimproved populations using large block plots. Results indicate that progress from selection and breeding of Douglas-fir is readily achievable, and realized genetic gains 5 years after planting are similar to those predicted based on results from progeny tests. Realized genetic gains were about 6% for height, 8% for diameter, and 28% for stem volume, compared to predicted genetic gains of about 8% for height, 7% for diameter, and 25% for stem volume. Large numbers of replicates (30–50) are required to detect statistically significant differences in height and diameter between improved and unimproved populations given genetic gains expected in a typical tree improvement program. West. J. Appl. For. 19(3):195–201.

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Den trees used by northern flying squirrels (Glaucomys sabrinus) in southeastern Alaska

Canadian Journal of Zoology ◽

10.1139/z02-155 ◽

2002 ◽

Vol 80 (9) ◽

pp. 1623-1633 ◽

Cited By ~ 35

Author(s):

V J Bakker ◽

K Hastings

Keyword(s):

Small Groups ◽

Random Trees ◽

High Rate ◽

Limiting Factor ◽

Glaucomys Sabrinus ◽

Flying Squirrel ◽

Flying Squirrels ◽

Northern Flying Squirrel ◽

Den Site Selection ◽

Northern Flying Squirrels

Northern flying squirrel (Glaucomys sabrinus) dens are reportedly associated with features characteristic of older forests, and den availability is a potential limiting factor in younger forests. We assessed den sites used by northern flying squirrels in southeastern Alaska, where we expected den-site selection to differ from more southerly forests, owing to increased thermal stress but reduced predation and competition. We located 27 squirrels in 76 dens and compared den trees with 1875 matched random trees. Most dens ([Formula: see text]73%) were in cavities and 21% were at heights of [Formula: see text]3 m. This high rate of cavity use, including cavities low in the bole, likely reflects the importance of weatherproof dens in this cool wet region. Northern flying squirrels preferentially used trees with indicators of cavity presence, selecting for snags and for larger diameter trees with bole entries, conks, abundant mistletoe, and dead tops. Although cavity availability is probably not limiting populations in this region currently, cavity-supporting trees would be one of the last elements of old-growth forests to develop in intensively logged stands. Retention of small groups of large snags and live trees exhibiting evidence of disease or physical defects would ensure availability of denning structures after logging.

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