Stability and density management in Douglas-fir plantations

2000 ◽  
Vol 30 (6) ◽  
pp. 910-920 ◽  
Author(s):  
J S Wilson ◽  
C D Oliver
Keyword(s):  
Pseudotsuga Menziesii ◽  
Size Variation ◽  
Douglas Fir ◽  
Potential Range ◽  
Stand Development ◽  
Experimental Plot ◽  
Time Period ◽  
Model Predictions ◽  
D Values ◽  
The Impact

Limited tree size variation in coastal Oregon, Washington, and British Columbia Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantations makes them susceptible to developing high height to diameter ratios (H/D same units) in the dominant trees. The H/D of a tree is a relative measure of stability under wind and snow loads. Experimental plot data from three large studies was used to evaluate the impact of initial planting densities and thinning on plantation H/D values. The H/D predictions from the experimental plot data match spacing trial results closely but are substantially different than distance-independent growth model predictions. The results suggest that plantation H/D values can be lowered and stability promoted through reduced planting densities or early thinning; however, later thinnings may not be effective in promoting stability, since they do not appear to lower H/D values. Higher initial planting densities shorten the time period during which thinning can be expected to effectively lower future H/D values. Time-sensitive thinning requirements in dense plantations make their management inflexible. The flexibility with which a stand can be managed describes the rigidity of intervention requirements and (or) potential range of stand development pathways.

scholarly journals Douglas fir impact on the dynamics and composition of humus in the soil of indigenous beech forest in western Serbia

2020 ◽  
pp. 83-95
Author(s):  
Olga Kostic ◽  
Miroslava Mitrovic ◽  
Pavle Pavlovic
Keyword(s):  
Organic Matter ◽  
Chemical Composition ◽  
Pseudotsuga Menziesii ◽  
Beech Forest ◽  
Control Site ◽  
Douglas Fir ◽  
Brown Soil ◽  
Decomposition Of Organic Matter ◽  
One Year ◽  
The Impact

This study investigates the impact of organic matter from Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) on the amount and composition of humus in acid brown soil in a climatoregional beech forest (Fagetum moesiacae montanum B. Jov. 1967 s.l.) on Mt. Maljen. To accomplish this objective, we performed a one-year litterbag decomposition experiment with litterfall from Fagus moesiaca and Pseudotsuga menziesii. The quantitative and qualitative content of humus and the intensity of the decomposition process of organic mat?ter from beech and Douglas fir were analysed. Less humus was found during the experiment under Douglas fir than under autochthonous beech at the control site, as well as a decreasing trend for humus levels and quality (unfavourable chemical composition). It was concluded that these changes, caused by the effects of the clearcutting of beech and, in the future, of Douglas fir, and the slower decomposition of organic matter from Douglas fir will contribute to further degradation of the beech habitat on Mt. Maljen in terms of productivity.

Assessing the impact of current and projected climates on Douglas-Fir productivity in British Columbia, Canada, using a process-based model (3-PG)

2010 ◽  
Vol 40 (3) ◽  
pp. 511-524 ◽  
Author(s):  
Nicholas C. Coops ◽  
Robbie A. Hember ◽  
Richard H. Waring
Keyword(s):  
British Columbia ◽  
Pseudotsuga Menziesii ◽  
Site Index ◽  
Douglas Fir ◽  
Climatic Variation ◽  
Climate Forecasts ◽  
Fine Spatial Resolution ◽  
Viable Approach ◽  
The Impact ◽  
Process Based Models

Predicted climate change is expected to significantly affect tree growth in many areas. We used a process-based model (Physiological Principles for Predicting Growth, 3-PG) to evaluate how climatic variation might alter growth of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. glauca (Beissn.) Franco and Pseudotsuga menziesii (Mirb.) Franco var. menziesii ) across biogeoclimatic zones in British Columbia. The results indicate that there will be significant changes in site index (defined as the height (in metres) of dominant trees at 50 years) over this century. In the interior, a reduction in site index is likely, particularly in stands with mid-range values of site index (25–30 m), with many of the interior bioecoclimatic zones predicted to experience a gradual mean decrease in site index by up to 10%. Individual sites may decrease by as much as 40% from current values. In contrast, site index along the coast overall is predicted to increase to a maximum of 43 m by 2080. In the Coastal Western Hemlock zone, however, mean site index is likely to increase from 26 m to only 34 m. We believe that combining process-based models with fine-spatial resolution climate forecasts offers a viable approach to assess future changes in forest productivity.

scholarly journals Size variation of chromomycin A3-band in chromosomes of Douglas fir, Pseudotsuga menziesii.

1992 ◽  
Vol 67 (6) ◽  
pp. 425-435 ◽  
Author(s):  
Masahiro HIZUME ◽  
Miyuki AKIYAMA
Keyword(s):  
Pseudotsuga Menziesii ◽  
Size Variation ◽  
Douglas Fir ◽  
Chromomycin A3

Effects of Nitrogen Fertilization on Growth of Grand Fir and Douglas-Fir Stands in Northern Idaho

1989 ◽  
Vol 4 (2) ◽  
pp. 54-57 ◽  
Author(s):  
Bahman Shafii ◽  
James A. Moore ◽  
John R. Olson
Keyword(s):  
Pseudotsuga Menziesii ◽  
Nitrogen Fertilization ◽  
Basal Area ◽  
Douglas Fir ◽  
Tree Size ◽  
Stand Development ◽  
Height Increment ◽  
Area Growth ◽  
Nitrogen Treatment ◽  
Northern Idaho

Abstract A study of nitrogen fertilization response in thinned and unthinned stands of grand fir (Abies grandis) and Douglas-fir (Pseudotsuga menziesii) in northern Idaho showed that the application of one urea nitrogen treatment applied at a rate of 200 lb N/ac resulted in a significantly higher average basal area growth over a 6-year post-treatment period. Nitrogen fertilization also resulted in a significant height increment increase over the same period. Fourteen years after treatment, fertilization had increased average tree size, in terms of total cubic volume, by 14% in unthinned and by 23% in thinned stands. A comparison of thinned and unthinned stands suggested an increase in tree size (>300%) over the same period without significant reduction in average total cubic volume per acre. Patterns of stand development were altered by nitrogen fertilization. West. J. Appl. For. 4(2):54-57, April 1989.

scholarly journals Stand development and stem form of the Douglas Fir (Pseudotsuga taxifolia Britt.) in the Netherlands.

1954 ◽  
Vol 2 (4) ◽  
pp. 265-272
Author(s):  
A. van Laar
Keyword(s):  
The Netherlands ◽  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Japanese Larch ◽  
Stand Development ◽  
Stem Form

Increment measurements on 65 heavily thinned trial plantations are used to show the development of stands in the Netherlands up to 30 years. Yields compare satisfactorily with Kanzow's yield tables for Prussia (1937), but are considerably below those of Grandjean and Soest [cf. F.A. 15 No. 567]. A taper table was derived from 801 trees measured after felling. At heights below 20 m. the stem forms of Douglas Fir and Japanese Larch, as shown in figures obtained by Schober [cf. F.A. 15 No. 1656], correspond closely with each other, but above 20 m. the former tapers more rapidly. KEYWORDS: Increment \ mensuration \ forests \ Pseudotsuga taxifolia \ Pseudotsuga menziesii \ aggr. form \ stem \ Pseudotsuga taxifolia \ Pseudotsuga menziesii \ aggr. yield \ taper \ tables \ stem form \ s \ yield tables (Abstract retrieved from CAB Abstracts by CABI’s permission)

The Impact of Logging on Red Squirrels in an Idaho Conifer Forest

1986 ◽  
Vol 1 (3) ◽  
pp. 73-76 ◽  
Author(s):  
Dean E. Medin
Keyword(s):  
Pseudotsuga Menziesii ◽  
Douglas Fir ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrel ◽  
Conifer Forest ◽  
Population Densities ◽  
Red Squirrels ◽  
Before And After ◽  
Second Year ◽  
The Impact

Abstract Red squirrel (Tamiasciurus hudsonicus) population densities were studied on logged and unlogged plots in an Idaho Douglas-fir (Pseudotsuga menziesii) forest. Squirrel population densities were estimated before and after logging by using spot-mapping methods. In the unlogged forest, we estimated 0.75 to 1.25 individuals/ac, but in the second year after logging there were only 0.05 to 0.08 squirrels/ac. Red squirrel densities on logged study plots were less than one-fifth those on unlogged plots. West. J. Appl. For. 1:73-76 July 1986.

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°.

scholarly journals Laminated Root Rot: New Considerations For Surveys

1997 ◽  
Vol 12 (2) ◽  
pp. 49-51 ◽  
Author(s):  
Walter G. Thies ◽  
Earl E. Nelson
Keyword(s):  
Disease Management ◽  
Pseudotsuga Menziesii ◽  
Root Rot ◽  
Signs And Symptoms ◽  
Douglas Fir ◽  
Stand Development ◽  
Inoculum Sources ◽  
Disease Survey ◽  
Phellinus Weirii

Abstract In 1981, Douglas-fir (Pseudotsuga menziesii) trees were placed into 3 disease classes of 45 trees each based on signs and symptoms of Phellinus weirii infection: infected, probably infected, and probably not infected. Trees that died during the course of the study were felled and their stumps and roots removed from the soil, cleaned carefully, dissected, and examined. In August 1991, the remaining study trees were similarly treated. Eight trees recorded as infected in 1981, based on the presence of ectotrophic mycelium, were found to be not infected in 1991. Only one-third of the trees near inoculum sources, and thus expected to be infected, were infected. Of the trees thought to be not infected, one-third were infected. Based on limited observations, laminated root rot appears to be distributed both as "pockets" (aggregated) that appear as openings early in stand development and in a more "diffuse" manner that may lead to openings late in stand development. These findings have implications for disease survey and disease management. West. J. Appl. For. 12(2):49-51.

Abscisic acid levels and stomatal behavior during drought and recovery in Douglas-fir (Pseudotsuga menziesii)

1980 ◽  
Vol 58 (12) ◽  
pp. 1370-1375 ◽  
Author(s):  
Edward G. Newville ◽  
William K. Ferrell
Keyword(s):  
Abscisic Acid ◽  
Water Potential ◽  
Pseudotsuga Menziesii ◽  
Stomatal Closure ◽  
Moisture Stress ◽  
Douglas Fir ◽  
Potential Range ◽  
Stomatal Behavior ◽  
Leaf Resistance ◽  
Growth Room

Foliage of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings from xeric and mesic environments was sampled during two induced, consecutive, drought cycles to determine relationships among leaf resistance, plant water potential, and abscisic acid (ABA) concentration. One group of seedlings was placed in a growth room; the other was kept outside at a nursery under natural conditions. During the first drought cycle, seedlings transpired similarly. During the second drought, xeric seedlings in the growth room and nursery initiated stomatal closure at greater levels of plant moisture stress (PMS) than in the first drought cycle, but stomatal behavior of mesic seedlings was unchanged. During the first drought cycle, a sharp increase in ABA concentration in both ecotypes coincided with increased leaf resistance within a narrow water-potential range. However, after xeric seedlings were rewatered and then subjected to drought, leaf resistances remained low even though the previous threshold PMS and ABA concentrations for stomatal closure were reached. For mesic seedlings in the growth room, ABA concentrations remained high after rewatering and slowly decreased with time, although recovery to predrought leaf resistances was largely completed 2 days after rewatering.

Epigenetic Studies in Psychotherapy: A Systematic Review

2020 ◽  
Vol 16 (2) ◽  
pp. 86-92
Author(s):  
Rafael Penadés ◽  
Bárbara Arias ◽  
Mar Fatjó-Vilas ◽  
Laura González-Vallespí ◽  
Clemente García-Rizo ◽  
...  
Keyword(s):  
Systematic Review ◽  
Dna Methylation ◽  
Mental Disorders ◽  
Epigenetic Modifications ◽  
Symptom Improvement ◽  
Epigenetic Changes ◽  
Main Hypothesis ◽  
Psychological Treatments ◽  
Time Period ◽  
The Impact

Background: Epigenetic modifications appear to be dynamic and they might be affected by environmental factors. The possibility of influencing these processes through psychotherapy has been suggested. Objective: To analyse the impact of psychotherapy on epigenetics when applied to mental disorders. The main hypothesis is that psychological treatments will produce epigenetic modifications related to the improvement of treated symptoms. Methods: A computerised and systematic search was completed throughout the time period from 1990 to 2019 on the PubMed, ScienceDirect and Scopus databases. Results: In total, 11 studies were selected. The studies were evaluated for the theoretical framework, genes involved, type of psychotherapy and clinical challenges and perspectives. All studies showed detectable changes at the epigenetic level, like DNA methylation changes, associated with symptom improvement after psychotherapy. Conclusion: Methylation profiles could be moderating treatment effects of psychotherapy. Beyond the detected epigenetic changes after psychotherapy, the epigenetic status before the implementation could act as an effective predictor of response.

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