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1
Douglas-Menzies, Lucinda. "Profile: Lucinda Douglas-Menzies." Astronomy & Geophysics 50, no. 1 (February 2009): 1.15–1.17. http://dx.doi.org/10.1111/j.1468-4004.2009.50115.x.
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Hassan, Robert. "Book Review: Heather Menzies, No Time: Stress and the Crisis of Modern Life. Vancouver: Douglas & Macintyre, 2005. ISBN 1—55365—045-X, 291 pp." Time & Society 16, no. 2-3 (September 2007): 411–13. http://dx.doi.org/10.1177/0961463x070160021202.
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Hadfield, James S., and Paul T. Flanagan. "Dwarf Mistletoe Pruning May Induce Douglas-Fir Beetle Attacks." Western Journal of Applied Forestry 15, no. 1 (January 1, 2000): 34–36. http://dx.doi.org/10.1093/wjaf/15.1.34.
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Abstract Fresh attacks of Douglas-firs (Pseudotsuga menziesii) by Douglas-fir beetles (Dendroctonus pseudotsugae) were found in a campground that had trees pruned to remove Douglas-fir dwarf mistletoe (Arceuthobium douglasii) infections. All Douglas-firs with a diameter at breast height (dbh) of at least 12.7 cm were examined. Beetle attacks were found on 41% of the pruned trees and 5% of the unpruned trees. Among pruned trees, both the average number of branches pruned and the average dbh were greater in trees attacked by Douglas-fir beetles than in unattacked trees. West. J. Appl. For. 15(1):34-36.
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Massicotte, H. B., R. Molina, L. E. Tackaberry, J. E. Smith, and M. P. Amaranthus. "Diversity and host specificity of ectomycorrhizal fungi retrieved from three adjacent forest sites by five host species." Canadian Journal of Botany 77, no. 8 (November 21, 1999): 1053–76. http://dx.doi.org/10.1139/b99-115.
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Seedlings of Abies grandis (Dougl.) Lindl. (grand fir), Lithocarpus densiflora (Hook. & Arn.) Rehd. (tanoak), Pinus ponderosa Dougl. ex Laws. (ponderosa pine), Pseudotsuga menziesii (Mirb.) Franco (Douglas-fir), and Arbutus menziesii Pursh (madrone) were planted in mixture and monoculture in soil collected from three adjacent forest sites in southwestern Oregon (a clearcut area, a 25-year-old Douglas-fir plantation, and a mature 90- to 160-year-old Douglas-fir - pine forest) to determine the effect of host tree diversity on retrieval of ectomycorrhizal morphotypes. In this greenhouse bioassay, 18 morphotypes of mycorrhizae were recognized overall from all soils with a total of 55 host-fungus combinations: 14 types with ponderosa pine, 14 with Douglas-fir, 10 with tanoak, 10 with grand fir, and 7 for madrone. Four genus-specific morphotypes were retrieved (three on ponderosa pine and one on Douglas-fir), even in mixture situations, demonstrating selectivity of some fungal propagules by their respective host. Five types were detected on all hosts, but not necessarily in soils from all sites. The remaining nine types were associated with two, three, or four hosts, which indicates a wide potential for interspecific hyphal linkages between trees. More morphotypes were retrieved from the monoculture treatments compared with the mixture treatments, although the differences were not significant. Several examples of acropetal replacement of one fungus by another (interpreted as succession) were recorded on all hosts during the course of the experiment. These results illustrate the importance of different host species in maintaining ectomycorrhizal fungus diversity, especially fungi with restricted host range, and the strong potential for fungal linkages between trees in forest ecosystems.Key words: fungal succession, fungal communities, compatibility, Arbutus menziesii, Pseudotsuga menziesii, Pinus ponderosa, Abies grandis, Lithocarpus densiflora.
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Hagerman, Shannon M., and Daniel M. Durall. "Ectomycorrhizal colonization of greenhouse-grown Douglas-fir (Pseudotsuga menziesii) seedlings by inoculum associated with the roots of refuge plants sampled from a Douglas-fir forest in the southern interior of British Columbia." Canadian Journal of Botany 82, no. 6 (June 1, 2004): 742–51. http://dx.doi.org/10.1139/b04-047.
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Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings were grown in the greenhouse in a sterilized mixture of forest soil and vermiculite, which had been inoculated with root fragments from one of six different ectomycorrhizal under story plant species (Arctostaphylos uva-ursi (L.) Spreng, P. menziessi, Salix bebbiana Bebb, Alnus viridis subsp. sinuata (Regel) Ä. Löve & and D. Löve (alder), Betula papyrifera Marsh. (paper birch), Populus tremuloides Michx.) and arbuscular mycorrhizal Calamagrostis rubescens Buckl. (pinegrass) sampled from a dry Douglas-fir forest in the southern interior of British Columbia. The overall objective of the present study was to investigate the inoculum potential of these ectomycorrhizal roots for colonizing Douglas-fir seedlings. A total of seven ectomycorrhizal morphotypes formed on the bioassay seedlings, which were colonized by all treatments except the control. Seedlings growing in soil inoculated with root fragments of Douglas-fir, Arctostaphylos, and paper birch had greater ectomycorrhizal richness and a higher percentage of colonized fine roots relative to the pinegrass and alder treatments. The community of ectomycorrhizal fungi that colonized the bioassay seedlings differed from that associated with some of the same refuge plants assessed in a previously reported field-based study at this site. Different ectomy corrhizal fungal colonization strategies and the retention of refuge plants are discussed in relation to the colonization of outplanted seedlings following clearcutting.Key words: ectomycorrhizae, refuge plants, inoculum potential, soil bioassay, Pseudotsuga menziesii.
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Kaundun, Shiv Shankhar, Philippe Lebreton, and Alain Bailly. "Needle flavonoid variation in coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) populations." Canadian Journal of Botany 76, no. 12 (December 1, 1998): 2076–83. http://dx.doi.org/10.1139/b98-187.
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The variability of six Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) populations was studied with the help of needle flavonoids. Of the two proanthocyanidins and six flavonols detected and measured by high performance liquid chromatography, myricetin and prodelphinidin allowed partial separation of the sampled coastal Douglas-fir populations into three geographical groups. Even though conspicuous differences were found between the northernmost and southernmost provenances, flavonoid markers were insufficient to identify the origin of a coastal Douglas-fir population without ambiguity. In accordance with other genetic markers, it would be inappropriate to recognize races within the sampled area of coastal Douglas-fir. From a biogenetical point of view, the synthesis of prodelphinidin appears to be governed by a gene present in two codominant allelic forms. The alleles are differently expressed from one population to another in such a way that there is a latitudinal cline of prodelphinidin throughout the sampled coastal Douglas-fir populations. The gradual decrease of prodelphinidin from south to north tends to support the idea that coastal Douglas-fir has migrated in this same direction from ice-free refugia of the Wisconsin glaciation period. To confirm the latitudinal cline and the mode of inheritance of prodelphinidin in coastal Douglas-fir, additional populations should be analyzed and segregation data from known pedigrees should be obtained respectively.Key words: Pseudotsuga menziesii var. menziesii, Pinaceae, flavonoids, geographical variation.
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Cole, Elizabeth, and Michael Newton. "Tenth-year survival and size of underplanted seedlings in the Oregon Coast Range." Canadian Journal of Forest Research 39, no. 3 (March 2009): 580–95. http://dx.doi.org/10.1139/x08-198.
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This study initiated a two-aged forest stand structure by underplanting 50-year-old stands, primarily of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) and Douglas-fir – western hemlock ( Tsuga heterophylla (Raf.) Sarg.), thinned to 19–33 m2/ha on interior and coastal sites in the Oregon Coast Range. Douglas-fir, grand fir ( Abies grandis (Dougl. ex D. Don) Lindl.) (interior site only), western hemlock, and western redcedar ( Thuja plicata Donn ex D. Don) were planted following thinning either uniformly or in gaps of 0.06 or 0.1 ha. Understory vegetation treatments included (i) a preharvest site preparation herbicide application and an untreated control at both sites and (ii) a postharvest herbicide release treatment at the interior site. Planting conditions and stock at the interior site were not ideal, so survival was adjusted for first-year mortality. Adjusted 10 year survival ranged from 27% to 56% for Douglas-fir, 47% to 65% for western hemlock, 61% to 80% for grand fir, and 78% to 96% for western redcedar. Tenth-year survival at the coastal site ranged from 79% to 92% for Douglas-fir, 61% to 75% for western hemlock, and 67% to 86% for western redcedar. All species grew moderately well beneath the lowest-density overstories, and size was better within gaps than matrices for most species. Understory site preparation improved size for most species. Browsing on Douglas-fir and western redcedar impacted size on both sites.
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Campbell, Bruce C., and Patrick J. Shea. "A SIMPLE STAINING TECHNIQUE FOR ASSESSING FEEDING DAMAGE BY LEPTOGLOSSUS OCCIDENTALIS HEIDEMANN (HEMIPTERA: COREIDAE) ON CONES." Canadian Entomologist 122, no. 5 (October 1990): 963–68. http://dx.doi.org/10.4039/ent122963-9.
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AbstractPectinmethylesterase (PME) activity was found in the salivary glands of nymphs and adults of a leaf-footed bug, Leptoglossus occidentalis Heidemann. Puncture wounds in cone scales resulting from PME activity in the saliva of these bugs were seen by staining with a 0.05% aqueous solution of ruthenium red. This staining technique can be used to estimate feeding damage by L. occidentalis on cones of western white pine (Pinus monticola Dougl.), sugar pine (P. lambertiana Dougl.), and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco).
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Moore, James A., David A. Hamilton Jr., Yu Xiao, and John Byrne. "Bedrock type significantly affects individual tree mortality for various conifers in the inland Northwest, U.S.A." Canadian Journal of Forest Research 34, no. 1 (January 1, 2004): 31–42. http://dx.doi.org/10.1139/x03-196.
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Individual tree mortality models for western white pine (Pinus monticola Dougl. ex D. Don), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), western redcedar (Thuja plicata Donn ex. D. Don), western hemlock (Tsuga heterophylla (Raf.) Sarg.), and western larch (Larix occidentalis Nutt.) were developed using data from permanent research plots located throughout the inland Northwest. The proposed linear logistic models included the following independent variables: diameter at breast height, basal area in larger trees, basal area per hectare, individual tree diameter increment, and a set of dummy variables for the six bedrock types, which were granite, basalt, metasedimentary, sedimentary, mixed glacial till, and deep deposit. The results show that rock type significantly affects individual tree mortality for western white pine, Douglas-fir, and western redcedar, while grand fir, western hemlock, and western larch were not affected. Western white pine and Douglas-fir growing on meta sedimentary rocks exhibited greater mortality probabilities than on other rocks. Mortality probabilities for western hemlock were low across all rock types, including "nutrient-poor" rocks like metasedimentary types.
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Vyse, Alan, Christine Ferguson, Suzanne W. Simard, Tamaki Kano, and Pasi Puttonen. "Growth of Douglas-fir, lodgepole pine, and ponderosa pine seedlings underplanted in a partially-cut, dry Douglas-fir stand in south-central British Columbia." Forestry Chronicle 82, no. 5 (September 1, 2006): 723–32. http://dx.doi.org/10.5558/tfc82723-5.
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The effects of partial cutting on seedling growth of three conifer species were studied at a very dry, hot interior Douglas-fir site near Kamloops, British Columbia. Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco), lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm.), and ponderosa pine (Pinus ponderosa Dougl. ex. P. & C. Laws.) seedlings were planted in mechanically prepared 50 cm × 50 cm patches under different canopy conditions created by harvesting 60% of the original stand volume. The prepared areas were selected to represent canopy closures from open to closed, slopes from 0 to 60%, and all aspects. After six years, survival of Douglas-fir, lodgepole pine and ponderosa pine was 78%, 76% and 70%, respectively. Light level had a strong influence on survival and condition. Growth of all species increased linearly with light, and was greatest for lodgepole pine, followed by ponderosa pine and Douglas-fir. Multiple regression analysis showed that six-year seedling size was most significantly affected by total light, and only occasionally by aspect, slope, or crown closure. The best models explained 53%, 47% and 42% of the variation in diameter of lodgepole pine, ponderosa pine, and Douglas-fir, respectively. Natural abundance 13C was positively correlated with light and soil moisture availability, reflecting higher photosynthetic capacity of all species in the wetter, open canopy conditions. Patterns in isotopic discrimination also indicated greater water use efficiency of Douglas-fir and ponderosa pine than lodgepole pine under low light conditions. Underplanting stands thinned to a basal area of less than 15m2 per ha offers a solution to regeneration difficulties on hot, dry Interior Douglas-fir sites. Key words: partial cutting, Douglas-fir, lodgepole pine, ponderosa pine, light, soil moisture, 13C, growth, survival, Opax Mountain Silvicultural Systems Project
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Simpson, David G., and Alan Vyse. "Planting stock performance: Site and RGP effects." Forestry Chronicle 71, no. 6 (December 1, 1995): 739–42. http://dx.doi.org/10.5558/tfc71739-6.
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Douglas-fir [Pseudotsuga menziesii var glauca (Beissn.) Franco], interior spruce [Picea glauca Moench (Voss), Picea engelmannii (Parry) and their naturally occurring hybrids] and lodge-pole pine (Pinus contorta Dougl.) seedlings were planted on several forest sites in south central British Columbia. At planting, root growth potential (number of newly elongated roots longer than 10 mm per seedling) was determined. Trees were assessed for survival and height for at least five years. Survival of Douglas-fir and growth of all three species was affected by planting site, probably reflecting moisture and growing season temperature differences among sites. High (> 70%) survival, but not total height or mean annual relative growth rate was associated with root growth potential levels greater than 10 new roots per seedling in interior spruce and lodgepole pine. Survival and growth of Douglas-fir were not related to root growth potential. Fertilization of interior spruce seedlings at planting decreased survival 18% over seven growing seasons, and did not affect growth of surviving seedlings. Key words: reforestation, root growth potential, seedling quality, Douglas-fir, interior spruce, lodgepole pine, field performance
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York, Robert A., Robert C. Heald, John J. Battles, and Jennifer D. York. "Group selection management in conifer forests: relationships between opening size and tree growth." Canadian Journal of Forest Research 34, no. 3 (March 1, 2004): 630–41. http://dx.doi.org/10.1139/x03-222.
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Replicated circular openings ranging in size from 0.1 to 1 ha were cleared in 1996 at Blodgett Forest Research Station, California, and planted with seedlings of six native species. After 5 years of postharvest growth, heights were measured and analyzed according to species, opening size, and location within opening. The sequence of mean height from tallest to shortest, according to species, was as follows: giant sequoia (Sequoiadendron giganteum (Lindl.) Buchholz) > incense-cedar (Calocedrus decurrens (Torr.) Florin) > Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) ≈ ponderosa pine (Pinus ponderosa Dougl. ex Laws.) > sugar pine (Pinus lambertiana Dougl.) ≈ white fir (Abies concolor (Gord. & Glend.) Lindl.). To describe the influence of openings size on seedling height, we use an information-theoretic approach to select from competing models that predicted fifth-year height from group selection opening size. Asymptotic fits (modeled with MichaelisMenton curves) were selected for giant sequoia, ponderosa pine, sugar pine, and incense-cedar. Quadratic fits were selected for white fir and Douglas-fir. Linear models predicting increasing growth with opening size were consistently ruled out for all species. Although a marked depression in seedling-height growth occurred along the edges within the openings, mean annual radial increment of the 90-year-old border trees surrounding the openings increased by 30%, compared with other canopy trees in the forested matrix between openings.
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Erickson, Heather E., Constance A. Harrington, and David D. Marshall. "Tree growth at stand and individual scales in two dual-species mixture experiments in southern Washington State, USA." Canadian Journal of Forest Research 39, no. 6 (June 2009): 1119–32. http://dx.doi.org/10.1139/x09-040.
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Planting with mixtures of tree species rather than single species is often considered during reforestation because of the potential increased productivity and other benefits. We examined tree growth at the stand and individual tree scales in two experiments contrasting monocultures with a 1:1 mixture of tree species: (1) Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) with a conifer of similar shade tolerance (western white pine ( Pinus monticola Dougl. ex D. Don)) and (2) Douglas-fir with a more shade-tolerant conifer (western hemlock ( Tsuga heterophylla (Raf.) Sarg.)). There was no effect of mixture on growth or yield in the Douglas-fir – western white pine combination. In the Douglas-fir – western hemlock combination, yields in the mixture equaled those in Douglas-fir stands because of the enhanced performance of Douglas-fir in the mixture. For Douglas-fir, the height/diameter (h/d) ratio was significantly less in mixture, suggesting reduced competition for light when grown with western hemlock. In contrast, the h/d ratio for western hemlock was significantly greater in mixture, suggesting increased competition for light when grown with Douglas-fir. Neighborhood analyses showed that tree growth was directly related to initial size and inversely related to relative neighbor size and that the h/d ratio was positively related to relative neighbor size. In general, the size of a neighboring tree influenced growth more than species identity. Relationships between h/d ratios and growth rates suggest that growth differences between Douglas-fir and western hemlock in mixture will eventually increase.
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Chen, Hua, Mark E. Harmon, and Robert P. Griffiths. "Decomposition and nitrogen release from decomposing woody roots in coniferous forests of the Pacific Northwest: a chronosequence approach." Canadian Journal of Forest Research 31, no. 2 (February 1, 2001): 246–60. http://dx.doi.org/10.1139/x00-167.
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Decomposition of woody roots in Sitka spruce (Picea sitchensis (Bong.) Carrière), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and ponderosa pine (Pinus ponderosa P. Laws. ex C. Laws.) dominated forests in Oregon, U.S.A. was studied using a chronosequence. Roots of five coniferous species were excavated from stumps with ages up to 46 years old. In order of increasing decomposition rate constant (k) the species were Douglas-fir < Sitka spruce < lodgepole pine (Pinus contorta Dougl. ex Loud.) < western hemlock (Tsuga heterophylla (Raf.) Sarg) < ponderosa pine. Variation in the proportion of bark, wood, and resin cores was correlated to these differences. Root wood showed the highest k, root bark the second, and resin cores the lowest. The occurrence of resin cores in woody roots of Douglas-fir, Sitka spruce, and lodgepole pine greatly slowed the decomposition of these species. White rots occurred frequently in ponderosa pine and lodgepole pine, whereas brown rots mostly appeared in Douglas-fir and Sitka spruce. Species with white rot had a higher k than those with brown rot. Decomposing woody roots started to release N after 2030% mass loss, a point when the dead root C/N ratio averaged 140.
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Parks, Catherine G., Evelyn L. Bull, Robert O. Tinnin, Jay F. Shepherd, and Arlene K. Blumton. "Wildlife Use of Dwarf Mistletoe Brooms in Douglas-Fir in Northeast Oregon." Western Journal of Applied Forestry 14, no. 2 (April 1, 1999): 100–105. http://dx.doi.org/10.1093/wjaf/14.2.100.
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Abstract Douglas-fir (Pseudotsuga menziesii) trees with and without dwarf mistletoe (Arceuthobium douglasii) brooms were examined for evidence of use by wildlife. Evidence of foraging occurred in 51% of the broomed trees and in 29% of the trees without brooms. Evidence of nesting by mammals occurred in 18% of the broomed trees and in none of the trees without brooms. Brooms used and those not used by wildlife were significantly different in type and volume. These findings suggest that retaining mistletoe brooms in stands may be important to provide nesting, foraging, resting and roosting habitat for mammals and birds. West. J. Appl. For. 14(2):100-105.
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Brandeis, Thomas J., Michael Newton, and Elizabeth C. Cole. "Underplanted conifer seedling survival and growth in thinned Douglas-fir stands." Canadian Journal of Forest Research 31, no. 2 (February 1, 2001): 302–12. http://dx.doi.org/10.1139/x00-174.
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In a multilevel study to determine limits to underplanted conifer seedling growth, Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), grand fir (Abies grandis (Dougl. ex D. Don) Lindl.), western redcedar (Thuja plicata Donn ex D. Don), and western hemlock (Tsuga heterophylla (Raf.) Sarg.) seedlings were planted beneath second-growth Douglas-fir stands that had been thinned to basal areas ranging from 16 to 31 m2/ha. Understory vegetation was treated with a broadcast herbicide application prior to thinning, a directed release herbicide application 2 years later, or no treatment beyond harvest disturbance. Residual overstory density was negatively correlated with percent survival for all four species. Broadcast herbicide application improved survival of grand fir and western hemlock. Western redcedar, grand fir, and western hemlock stem volumes were inversely related to overstory tree density, and this effect increased over time. There was a strong indication that this was also the case for Douglas-fir. Reduction of competing understory vegetation resulted in larger fourth-year stem volumes in grand fir and western hemlock.
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Mondek, Jan, and Martin Baláš. "Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and its role in the Czech forests." Journal of Forest Science 65, No. 2 (March 5, 2019): 41–50. http://dx.doi.org/10.17221/9/2019-jfs.
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The presented study summarizes the results concerning the effects of cultivation of Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) in the Czech Republic. It focuses on more recent results, published especially in the last decades, it includes also older relevant data. It describes the intensity of production as well as non-production forest functions in the conditions of the Czech Republic. It analyses the research results concerning the volume and value production in comparison with native tree species, also documents effects on soil and herb vegetation diversity in forest ecosystems, and from point of view of stability and cultivation in the last period. Main target is defined by the comparison with the Norway spruce, which can be with advantages substituted partly by this species, with favourable impact on amount and value of the timber production, on the forest soil and ground vegetation biodiversity status. Also the stability of forest stands can be supported considerably. This species represents important alternative to the Norway spruce in lower and middle altitudes and it can contribute considerably to the competitiveness of the Czech forestry.
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Hart, V., M. Nentvichová-Hartová, and P. Tauchman. "Analysis of herbicide effects on Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) natural regeneration." Journal of Forest Science 56, No. 5 (May 28, 2010): 209–17. http://dx.doi.org/10.17221/77/2009-jfs.
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Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) natural regeneration under parent stand after weed suppression was investigated in the area of the Training Forest Enterprise in Kostelec nad Černými lesy. The study evaluates two measurements made in a two-year interval. The parent stand, where Douglas fir grows in mixture with our domestic tree species, is one of the oldest and most productive stands at the Training Forest Enterprise in Kostelec nad Černými lesy. Herbicides for the control of weeds were applied onto three permanent experimental plots under the parent stand. Measurements done on the plots show a high potential of natural regeneration in areas where the negative impact of forest weeds was suppressed. This conclusion is acknowledged by the high seedling number found on research plots treated with herbicides. The number of Douglas fir seedlings varied from 21,600 per hectare counted on the plot treated with Dominator to 26,650 seedlings on the plot with Velpar treatment even six years after the soil preparation. Statistical analysis confirmed that the seedling number on the plot without any chemical preparation was significantly lower, only 950 individuals per hectare (χ<sup>2</sup> = 926.84, df = 3, P << 0.01).
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Owens, John N., Anna M. Colangeli, and Sheila J. Morris. "Factors affecting seed set in Douglas-fir (Pseudotsuga menziesii)." Canadian Journal of Botany 69, no. 2 (February 1, 1991): 229–38. http://dx.doi.org/10.1139/b91-033.
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Cone and seed development in Douglas-fir were studied from pollination until seed release in 1986. Cone abortion at, and shortly after, pollination was high, resulting from a combination of low temperatures and possibly high moisture and populations of microorganisms on cones. Seed potential averaged about 75 seeds per cone with 31 filled seed per cone, giving an average seed efficiency of 39%. The major loss of seed resulted from insufficient pollen in the ovules. Other causes were ovule and embryo abortion at various stages of development. The effects of prezygotic and postzygotic events on seed set are discussed with respect to the reproductive success of Douglas-fir. Key words: Douglas-fir, seed set, cone, ovule, development, abortion.
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Kostic, Olga, Miroslava Mitrovic, and Pavle Pavlovic. "Douglas fir impact on the dynamics and composition of humus in the soil of indigenous beech forest in western Serbia." Zbornik Matice srpske za prirodne nauke, no. 138 (2020): 83–95. http://dx.doi.org/10.2298/zmspn2038083k.
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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.
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Lei, Hua, Michael R. Milota, and Barbara L. Gartner. "Between- and Within-Tree Variation in the Anatomy and Specific Gravity of Wood in Oregon White Oak (Quercus Garryana Dougl.)." IAWA Journal 17, no. 4 (1996): 445–61. http://dx.doi.org/10.1163/22941932-90000642.
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In order to analyze the variation in wood properties within and between trees of an underutilized tree species, we sampled six Oregon white oak (Quercus garryana Dougl.) trees from an 80-year old mixed stand of Q. garryana and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) in the Coast Range of Western Oregon, USA. Fibre length, earlywood vessel diameter, tissue proportions, and specific gravity were measured on samples across the diameter at two heights. Trees had a slight lean (2-12°), so we sampled separately both radii of a diametric strip that ran from the lower to upper side of lean.
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Thomas, K. D., and C. E. Prescott. "Nitrogen availability in forest floors of three tree species on the same site: the role of litter quality." Canadian Journal of Forest Research 30, no. 11 (November 1, 2000): 1698–706. http://dx.doi.org/10.1139/x00-101.
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Forest floor samples from a 25-year-old plantation of three tree species (Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), lodgepole pine (Pinus contorta Dougl. var. latifolia Engelm.), and paper birch (Betula papyrifera Marsh.)) growing on the same site were incubated (aerobically) in the laboratory for 29 days. Rates of N mineralization in the forest floors of Douglas-fir (165.1 µg/g) was significantly greater than either birch (72.9 µg/g) or lodgepole pine (51.2 µg/g). Douglas-fir forest floors also had the highest N concentration, lowest C/N ratio, and highest NH4-N concentrations, followed by paper birch and lodgepole pine. Douglas-fir forest floors also mineralized more N per unit of either N or C than the other species. There were no differences in rates of CO2-C mineralization in forest floors among the three species. Nitrogen mineralization rates were positively correlated with the N concentration of the forest floor (r2 = 0.81) and also with the C/N and NH4-N concentration of the forest floor. Nitrogen concentration, C/N, and lignin/N of foliar litter were poor predictors of N mineralization rates resulting from Douglas-fir litter having the lowest N concentrations in litter but the highest rates of net N mineralization in the forest floor. Nitrogen mineralization in the forest floor was negatively correlated (r2 = 0.67) with the lignin concentration in foliar litter. Douglas-fir litter had low lignin concentrations, which may allow more of the mineralized N to remain in inorganic forms rather than being bound in humus. Our results suggest that a component of Douglas-fir might improve N availability in coniferous forest floors.
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Nealis, V. G., M. K. Noseworthy, R. Turnquist, and V. R. Waring. "Balancing risks of disturbance from mountain pine beetle and western spruce budworm." Canadian Journal of Forest Research 39, no. 4 (April 2009): 839–48. http://dx.doi.org/10.1139/x09-014.
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The effect of removing lodgepole pine ( Pinus contorta Dougl. ex Loud.) and retaining Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) to reduce the risk of disturbance from mountain pine beetle ( Dendroctonus ponderosae Hopk.) in mixed conifer stands in southern British Columbia, Canada, on population processes influencing outbreaks of western spruce budworm ( Choristoneura occidentalis Free.) was evaluated in 10 paired (open vs. closed) field plots. Overall feeding damage to Douglas-fir was significantly, but only slightly, lower in open stands compared with closed stands. Although open plots tended to recruit more budworms, the losses resulting from the dispersal of spring-emerging budworms in search of feeding sites were significantly greater in open plots. The forest management benefits of these early season losses were mitigated, however, by more mortality of budworms from natural enemies, particularly diseases, in the closed plots during the budworm feeding period. These results are discussed in terms of compensating population processes and balancing objectives in forest pest management. In this case, selective harvesting of lodgepole pine as a mitigation strategy for the mountain pine beetle conserved the midterm timber supply potential represented by associated Douglas-fir even in the presence of an outbreak of the western spruce budworm.
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Huggard, David J., and André Arsenault. "Conifer seed predation in harvested and burned dry Douglas-fir forests in southern British Columbia." Canadian Journal of Forest Research 39, no. 8 (August 2009): 1548–56. http://dx.doi.org/10.1139/x09-084.
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Consumption of seeds of Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) and ponderosa pine ( Pinus ponderosa Dougl. ex P. & C. Laws.) was measured in dry Douglas-fir forest at the Opax Mountain Silvicultural Systems site and a nearby burned area as one component of understanding limited natural regeneration in these sites. Seeds were placed in plots surrounded by a physical barrier to invertebrates, enclosed in mesh impermeable to small mammals, covered by litter, or unprotected in clear-cut, partially harvested, uncut, and burned areas and monitored for three several-day sessions in 2 years. Daily survival rates of unprotected seeds of both species were equally low: 0.63 in uncut forest, 0.45 in partially harvested and clear-cut sites, and 0.03 in the burned area. Experimental reductions of coarse woody debris reduced seed predation moderately in patch cuts but not in uncut forest. Litter cover or selective exclosure of ground-dwelling invertebrates reduced seed losses only slightly, whereas small mammal exclosures eliminated most seed loss. Deer mice ( Peromyscus maniculatus Wagner) are likely the most important seed predators. High rates of seed predation in dry Douglas-fir forests likely limit natural regeneration in harvested and burned stands.
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Butler, B. W., B. W. Webb, D. Jimenez, J. A. Reardon, and J. L. Jones. "Thermally induced bark swelling in four North American tree species." Canadian Journal of Forest Research 35, no. 2 (February 1, 2005): 452–60. http://dx.doi.org/10.1139/x04-194.
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Bark protects both the living phloem and the vascular cambium of trees. For some tree species the bark has been observed to swell in the radial direction when heated by nearby flames, possibly providing additional protection from thermal injury. In this study, detailed measurements of bark swelling (tumescence) are reported for four species: Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), ponderosa pine (Pinus ponderosa Dougl. ex Laws.), chestnut oak (Quercus prinus L.), and red maple (Acer rubrum L.). Tests were conducted on over 574 samples extracted from 44 separate trees. The results clearly show that bark swelling occurs in the mature bark of Douglas-fir and to a lesser degree in chestnut oak. Ponderosa pine and red maple did not exhibit statistically significant swelling, but rather a modest decrease in overall bark thickness with heating. Significant swelling in Douglas-fir bark began at approximately 125 °C and resulted in a 15%80% increase in overall bark thickness. Swelling of chestnut oak was observed to begin at an average temperature of 225 °C and resulted in a 5%10% increase in total bark thickness. The increase in bark thickness occurred primarily in the radial direction in mature bark.
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Mauer, O., and E. Palátová. " Root system development in Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) on fertile sites." Journal of Forest Science 58, No. 9 (October 23, 2012): 400–409. http://dx.doi.org/10.17221/94/2011-jfs.
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The paper analyses the root system development in the artificially established stands of Douglas fir aged 10, 20, 30, 60 and 80 years on aerated soils (Cambisols) without skeleton. On these sites, the Douglas fir develops a uniform root system of substitute taproots and anchors, which has great predispositions to assure the good mechanical stability of trees as well as its resistance to sudden changes in upper soil horizons. Several anchors growing in positive geotropic direction shoot from the stem base, several slant anchors shooting from the side of the stem base turn into the positive geotropic direction of growth. In humus horizons, horizontal skeletal roots shoot from the stem base, which turn into lower soil horizons in an “elbow-pipe” manner and from which shoot positively geotropically growing anchors. Trees of Douglas fir develop this type of root system already at an age of twenty years.
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Sychra, D., and O. Mauer. "Prosperity of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) plantations in relation to the shelter." Journal of Forest Science 59, No. 9 (October 29, 2013): 352–58. http://dx.doi.org/10.17221/84/2012-jfs.
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The study evaluates the mortality, growth and qualitative characteristics of Douglas fir transplants planted out on clear-cut areas with different shelter. We assessed 11 clearings situated in the Forest Site Complex 4K – acidic beech (Fagetum acidophilum). The young trees were assessed 3 years after planting for the following parameters: total shoot length, increment, root collar diameter, number of multiple stems, stem curvature, crown form, length of needles, colour of needles and frost damage. The lowest mortality and the best growth of Douglas fir plants were recorded in small, sheltered gaps. Large, unsheltered gaps showed low survival, slower growth and poor vitality of plants.
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Pulkrab, K., M. Sloup, and M. Zeman. "Economic Impact of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) production in the Czech Republic." Journal of Forest Science 60, No. 7 (August 5, 2014): 297–306. http://dx.doi.org/10.17221/27/2014-jfs.
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The article addresses the issues of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) production in the Czech Republic (CR). Our analysis shows that the tree species can occupy 149,616–163,713 ha in the CR (with respect to ecological limits set by the Czech legislation). The potential economic effect expressed by the gross yield of forest production might be higher by 27–30 million EUR·yr<sup>–1</sup>. The results of the analysis support the forest owners’ interest to extend Douglas-fir production in the CR, similarly like it has been extended systematically in all European countries where natural conditions allow.
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Lavadinovic, Vera, Vasilije Isajev, Zoran Miletic, and Milun Krstic. "Variability of nitrogen content in the needles of Douglas-fir (Pseudotsuga menziesii Mir/Franco) provenances." Genetika 43, no. 2 (2011): 407–17. http://dx.doi.org/10.2298/gensr1102407l.
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Nitrogen content in the needles of twenty Douglas-fir provenances, originating from different sites within the native range of the species in the USA, was studied in a Douglas-fir provenance test established at the montane beech site on acid brown soil. Based on the variability of nitrogen content in the needles, the intensity and dynamics of the physiological processes of Douglas-fir mineral nutrition were analyzed as the indicators of Douglas-fir adaptive potential to the sites in Serbia. All the trees of the study provenances were of the same age and grown under the same site and population conditions. The quantities of nitrogen absorbed in Douglas-fir needles were correlated with the geographical characteristics of the native sites of the observed provenances. The differences in nitrogen content in Douglas-fir needles point out the variability in the intensity of the physiological processes in the genotypes of the different provenances. Since the study Douglas-fir trees are cultivated on relatively small areas, in more or less equal general conditions, it can be concluded that the parameters of mineral nutrition depend on the genotypes constituting the gene pool of the study Douglas-fir provenances.
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Podrázský, V., A. Martiník, K. Matějka, and J. Viewegh. "Effects of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) on understorey layer species diversity in managed forests." Journal of Forest Science 60, No. 7 (August 5, 2014): 263–71. http://dx.doi.org/10.17221/49/2014-jfs.
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In total, 67 parallel plots were chosen from the database of 153 phytosociological relevés made in the Douglas-fir and parallel Norway spruce, European Beech and oak-dominated stands to find influences of this introduced tree species on the understorey layer in totally 12 localities in the whole Czech Republic territory. Douglas-fir stands influence their habitats, which was indicated by species composition changes in the ground vegetation, as well as by abundance and dominance of particular species. Douglas-fir cultivation increases species diversity of the stands, but decreases their abundance. Described differences in understorey are not so noticeable when European beech and sessile oak stands are substituted by Douglas-fir once. But even the significant phenomenon of striking nitrophilous species such as Geranium robertianum, Urtica dioica and Galium aparine occurs here. This indicates a high content of available nitrates in the humus and top-soil horizons.
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Konnert, Monika, and Barbara Fussi. "Natürliche und künstliche Verjüngung der Douglasie in Bayern aus genetischer Sicht." Schweizerische Zeitschrift fur Forstwesen 163, no. 3 (March 1, 2012): 79–87. http://dx.doi.org/10.3188/szf.2012.0079.
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Genetic aspects related to natural and artificial regeneration of Douglas-fir in Bavaria One of the most important factors when planting Douglas-fir is choosing the most suitable provenance for the site. Under climate change, genetic diversity as the basis for adaptation is of increasing importance. Both aspects, provenance and genetic diversity, have to be considered if natural regeneration of adult stands or planting of new stands are discussed. Numerous provenance trials have proven that the most suitable provenances for Bavaria originate from the coastal region west of the Cascade Mountains in Washington (Pseudotsuga menziesii var. menziesii). The interior variety (Pseudotsuga menziesii var. glauca and P. menziesii var. caesia) is unsuitable both because of growth rate and susceptibility to needle cast. However, not only coastal Douglas-fir was planted in Bavaria. Isozyme analysis showed that around 20% of the Bavarian stands represented interior Douglas-fir or a mixture of coastal and interior variety. Through natural regeneration the genetic structure of the adult trees is passed on to the following generation. If gene flow through pollen or seed from neighbouring stands occurs, significant changes in the genetic composition of natural regeneration in comparison with the adult generation will be observed. The same is true for the seed collected from adult stands. This must be taken into consideration when stands are selected as registered seed collection stands. Stands with low genetic diversity and mixture of green and gray variety of Douglas-fir have to be excluded from seed collection. To maintain an appropriate level of genetic diversity in the seed, cones should be collected from at least 20 trees per stand. This should be considered the absolute minimum. Concerning the level of genetic diversity in seed collections from Germany, West Washington (USA) and France (seed orchards), no clear differences were observed.
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Hawkins, Ashley E., and Terry W. Henkel. "Native forest pathogens facilitate persistence of Douglas-fir in old-growth forests of northwestern California." Canadian Journal of Forest Research 41, no. 6 (June 2011): 1256–66. http://dx.doi.org/10.1139/x11-053.
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Forest pathogens and insects can accelerate tree mortality, increase stand structural heterogeneity, and alter tree community composition. In northern California, the canopy trees Abies concolor var. lowiana (Gord. & Glend.) Lemmon (white fir) and Pseudotsuga menziesii var. menziesii (Mirbel) Franco (Douglas-fir) co-occur but vary in shade tolerance and regenerative abilities following disturbance. Field observations suggested that mortality and turnover of white fir exceeded that of Douglas-fir and that native pathogens may be important drivers in the absence of fire. Pathogens and bark beetles were sampled in old-growth white fir – Douglas-fir stands in northwestern California to assess their contribution to tree mortality, gap formation, and regeneration. We determined abundances and size class distributions of canopy trees, presence of pathogens and bark beetles, and causes of tree mortality. We sampled canopy gaps and closed-canopy forests for overstory species composition, cause of mortality of gap-maker trees, and regeneration of white fir and Douglas-fir. Root-rot fungi accounted for significantly higher mortality and gap formation in white fir than in Douglas-fir. Relative seedling–sapling density of Douglas-fir was higher in pathogen-induced canopy gaps than in closed-canopy forest. In the absence of fire, native forest pathogens enable regeneration and persistence of Douglas-fir by enhancing mortality of white fir, resulting in canopy gap formation.
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Harrington, Timothy B., and John C. Tappeiner. "Long-term effects of tanoak competition on Douglas-fir stand development." Canadian Journal of Forest Research 39, no. 4 (April 2009): 765–76. http://dx.doi.org/10.1139/x09-004.
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In 1- to 2-year-old Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco var. menziesii) plantations near Cave Junction and Glendale, Oregon, sprout clumps of tanoak (Lithocarpus densiflorus (Hook. & Arn.) Rehd.) and other hardwoods were removed with herbicides in April 1983 to leave relative covers of 0%, 25%, 50%, or 100% of the nontreated cover, which averaged 15%. In 1996 (Cave Junction) and 1998 (Glendale), precommercial thinning (PCT) of Douglas-fir and cutting of nonconifer woody species were operationally applied across the four densities of tanoak. In 2005, Douglas-fir in 0% relative cover of tanoak averaged 5–8 cm larger at breast height and 3–6 m taller, and had two to four times the net stand volume of those growing in 100% relative cover. From 1999 to 2005, Douglas-fir stand growth accelerated more rapidly in tanoak relative covers of 0% and 25% than in covers of 50% and 100%. Differential development of Douglas-fir and hardwoods in relative covers of 0%, 25%, and 100%, followed by selection of crop trees via PCT, resulted in three distinct stand structures: pure stands of Douglas-fir with a single canopy layer 12–16 m tall, mixed stands with overstory Douglas-fir (12 m) and midstory hardwoods (7 m), and mixed stands with a single canopy layer (8–9 m).
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Miller, Richard E., Richard E. Bigley, and Steve Webster. "Early Development of Matched Planted and Naturally Regenerated Douglas-Fir Stands After Slash Burning in the Cascade Range." Western Journal of Applied Forestry 8, no. 1 (January 1, 1993): 5–10. http://dx.doi.org/10.1093/wjaf/8.1.5.
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Abstract We compared matched planted and naturally regenerated plots in 35- to 38-year-old Douglas-fir (Pseudotsuga menziesii var. menziesii) stands at seven locations in western Washington and Oregon. Total number of live stems is similar, but stands planted to Douglas-fir average 26 more live stems/ac of Douglas-fir and 39 fewer stems/ac of other conifers than do naturally regenerated stands. Despite an average 2-yr delay in planting after burning, dominant Douglas-fir in planted stands average 3 fewer years than natural regeneration to attain breast height after burning. Volume of all live trees (1.6 in. dbh and larger) and of Douglas-fir average 40% greater on planted plots. Volume of live conifers 7.6 in. dbh and greater average 41% greater on planted plots as compared to naturally regenerated plots (2977 vs. 2118 ft³/ac). Differences that developed on these plots are probably less than differences that would be shown by plantations being established today with prompt planting and improved nursery stock and planting methods. Planting slash-burned clearcuts in this general area of the Cascade Range resulted in faster volume production. West. J. Appl. For. (8)1:5-10.
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Campbell, Rochelle, Dan J. Smith, and André Arsenault. "Multicentury history of western spruce budworm outbreaks in interior Douglas-fir forests near Kamloops, British Columbia." Canadian Journal of Forest Research 36, no. 7 (July 1, 2006): 1758–69. http://dx.doi.org/10.1139/x06-069.
Full textAbstract:
Western spruce budworm (Choristoneura occidentalis Freeman) is a native defoliator of forests in the interior Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) forests of British Columbia, Canada. Dendrochronological techniques and the software program OUTBREAK were used to reconstruct a defoliation history of Douglas-fir for 19 forest sites near Kamloops in central British Columbia. By comparing the radial-growth response of ponderosa pine (Pinus ponderosa Dougl. ex P. Laws. & C. Laws.) with that of Douglas-fir growing in nearby but separate stands, eight western spruce budworm outbreaks over the past 300 years were distinguished. Although there is considerable variation in the timing and duration of these western spruce budworm events at the stand level, synchronous outbreaks have occurred in approximately 30- to 43-year cycles. Spectral analyses of a composite time series from all stands showed similar and consistent intervals between outbreaks. Climatic variation appears to have been important to budworm outbreaks in the 20th century. Notable outbreaks tended to occur during years with average spring air temperatures following winters with less than average precipitation. Based on this finding, it is proposed that with high over-winter survival rates and a longer growing season, the duration of outbreaks may increase in the future.
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Koumbi-Mounanga, Thierry, Tony Ung, Kevin Groves, Brigitte Leblon, and Paul Cooper. "Moisture and surface quality sensing of Douglas-fir (Pseudotsuga menziesii var. menziesii) veneer products." Forestry Chronicle 89, no. 05 (October 2013): 646–53. http://dx.doi.org/10.5558/tfc2013-116.
Full textAbstract:
The potential of near-infrared spectroscopy (NIRS) to estimate moisture content (MC) and surface inactivation parameters of Douglas-fir (Pseudotsuga menziesii var. menziesii) veneer products was assessed. The best prediction model for MC was produced for the lower range of MC (0%–50%) of Douglas-fir veneers. Exposure at 180°C produced surface colour changes and the CIE-L*a*b* colour parameters measuring colour changes were better estimated using the 400 nm to 900 nm spectral data than the 1100 nm to 2400 nm spectral data. Increased exposure time resulted in lower wettability and hence increasing contact angles, especially when ethylene glycol and formamide were used as solvents. NIRS-based predictions of contact angles were better when the angles were measured using formamide than when they were measured using ethylene glycol. Lap shear tensile strengths of bonds made with phenol formaldehyde (PF) resin decreased with exposure times. NIRS-based predictions of tensile strengths were also estimated and we found strong negative relationships between contact angle and tensile strength, whatever the probe solvent used (water, glycerol, ethylene glycol and formamide). It is apparent that NIRS can differentiate veneers samples that had undergone high temperature exposure, which resulted in lower wetting properties and somewhat lower adhesion bond strength.
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Erbilgin, Nadir, Andrew J. Storer, David L. Wood, and Thomas R. Gordon. "Colonization of cut branches of five coniferous hosts of the pitch canker fungus by Pityophthorus spp. (Coleoptera: Scolytidae) in central, coastal California." Canadian Entomologist 137, no. 3 (June 2005): 337–49. http://dx.doi.org/10.4039/n04-074.
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AbstractPitch canker of pines (Pinus spp.) and Douglas-fir (Pseudotsuga menziesii (Mirbel) Franco) (Pinaceae) is caused by the fungus Fusarium circinatum Nirenberg et O'Donnell. In California, infections by F. circinatum occur largely through wounds caused by insects. Field experiments were initiated to determine whether the colonization activities of twig beetles, Pityophthorus spp. (Coleoptera: Scolytidae), could explain the incidence of pitch canker on Monterey pine (P. radiata D. Don), Bishop pine (P. muricata D. Don), ponderosa pine (P. ponderosa var. ponderosa Dougl.), knobcone pine (P. attenuata Lemm.), and Douglas-fir. Asymptomatic branches were cut from each of four pairs of tree species (Monterey–Bishop, Monterey–ponderosa, Monterey–knobcone, Monterey–Douglas-fir) at four sites and attached to the lower canopy of both heterospecific and conspecific host trees (total of four combinations per pair). After 10 weeks, branches were collected and placed in rearing tubes in the laboratory. Emerging insects were identified and placed on a Fusarium-selective medium. Monterey, Bishop, and ponderosa pines were more heavily infested by Pityophthorus spp. than Douglas-fir and knobcone pine. Furthermore, more Pityophthorus beetles emerged from Monterey pine branches placed in Monterey pine canopies than from Monterey pine branches placed in Bishop or ponderosa pine canopies, indicating that reduced emergence (colonization) was caused by the hetero specific host. Relatively fewer insects emerged from sites containing either Monterey and knobcone pines or Monterey pine and Douglas-fir. Fusarium circinatum was not isolated from emerging Pityophthorus spp. Susceptibility of the five host species, based on mean lesion lengths resulting from mechanical inoculations, varied significantly. The longest lesions were on Monterey pine and the shortest were on ponderosa pine and Douglas-fir. The low incidence of pitch canker on Douglas-fir and ponderosa pine in nature compared with that on Monterey, Bishop, and knobcone pines may be explained by the low colonization by twig beetles and the greater resistance of Douglas-fir and ponderosa pine to this disease, compared with the other three hosts.
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Iliadis, Lazaros, Shawn D. Mansfield, Stavros Avramidis, and Yousry A. El-Kassaby. "Predicting Douglas-fir wood density by artificial neural networks (ANN) based on progeny testing information." Holzforschung 67, no. 7 (October 1, 2013): 771–77. http://dx.doi.org/10.1515/hf-2012-0132.
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Abstract A heuristic wood density prediction model has been developed by means of artificial neural networks (ANNs). Four populations of 32-year-old coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesi) trees representing 20 full-sib families growing on comparable sites were in focus of this study. Tree height, diameter, volume, wood density, and acoustic velocity data from 632 trees were considered for the calculations. Two different ANN platforms were developed employing different classes and architectures, namely, the multilayer feed-forward (MLFF) and modular (MOD) models. After establishing the optimal configuration of the model, a MLFF network and a MOD neural network (with the obtained optimal structure) were developed and tested without cross-validation by employing a typical training and testing set methodology. To this purpose, the data set was divided in 480 trees for training and 152 trees for validation. A significant relationship between actual and predicted wood density was obtained with R2 values of 0.50 and 0.52 for the two networks, respectively, demonstrating their predictive potential for wood density estimation. A classic multiple regression analysis produced substantially lower predictive power with an R2 of 0.23. The application of ANNs as a viable predictive tool in determining wood density using growth and acoustic velocity data without additional intrusive sampling and laboratory work was demonstrated. An additional work including other species is required for these approaches.
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Chanway, C. P., and F. B. Holl. "Influence of soil biota on Douglas-fir (Pseudotsuga menziesii) seedling growth: the role of rhizosphere bacteria." Canadian Journal of Botany 70, no. 5 (May 1, 1992): 1025–31. http://dx.doi.org/10.1139/b92-127.
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The influence of soil biota on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedling growth was investigated by sowing seed collected from two ecologically distinct zones in British Columbia, Chilliwack and Williams Lake, in soil collected from the same two areas. Seedling biomass of both Douglas-fir ecotypes was greatest in unpasteurized soil collected from the same area as was the seed, but pasteurization negated this effect. In addition, Chilliwack seedlings responded specifically to biota present only in Chilliwack soil. To determine if rhizosphere bacteria were involved in these growth responses, bacteria were isolated from the rhizosphere of wild Douglas-fir seedlings collected from both locations, and putative growth promoting bacteria were selected in a screening experiment. Selected bacteria were then tested for seedling growth response specificity using a factorial design in which seed, soil, and bacteria from both locations were evaluated in all combinations. Inoculation of Douglas-fir seed with some of the selected bacterial isolates increased seedling biomass in pasteurized soil to a level similar to that of seedlings grown in unpasteurized soil, but there was no evidence that adaptive relationships involving bacteria, Douglas-fir, and the soil in which they naturally grew were important in effecting seedling growth promotion. However, Douglas-fir shoot biomass increased 39% and root biomass 68% after bacterial inoculation in some treatment combinations involving pasteurized soil. Key words: Douglas-fir seedlings, growth, rhizosphere bacteria.
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Fight, Roger D., James M. Cahill, Thomas D. Fahey, and Thomas A. Snellgrove. "A New Look at Pruning Coast Douglas-Fir." Western Journal of Applied Forestry 3, no. 2 (April 1, 1988): 46–48. http://dx.doi.org/10.1093/wjaf/3.2.46.
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Abstract Pruning of coast Douglas-fir for (Pseudotsuga menziesii var. menziesii) lumber was evaluated by using new product-recovery information and new computer software. The results showed that higher financial returns from pruning are achieved by pruning early in stands that have a higher site index and that will be fertilized. Interest rates and the premium for clear lumber will have major impacts on the dollar return from pruning. West. J. Appl. For. 3(2):46-48, April 1988.
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Ningre, François, Jean-Marc Ottorini, and Noël Le Goff. "Trajectoires d’autoéclaircie du Douglas (Pseudotsuga menziesii ) en France." Revue Forestière Française, no. 1 (2016): 323. http://dx.doi.org/10.4267/2042/62130.
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Strang, R. M. "Douglas-fir (Pseudotsuga menziesii) and the Scots connection." Forestry Chronicle 68, no. 2 (April 1, 1992): 246–48. http://dx.doi.org/10.5558/tfc68246-2.
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Haug, Corinne M., Kenneth J. Reimer, and William R. Cullen. "Arsenic uptake by the Douglas-fir (Pseudotsuga menziesie)." Applied Organometallic Chemistry 18, no. 12 (2004): 626–30. http://dx.doi.org/10.1002/aoc.656.
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Smit, H. P., W. G. Keltjens, and N. van Breemen. "Effects of soil acidity on Douglas fir seedlings. 2. The role of pH, aluminium concentration and nitrogen nutrition (pot experiment)." Netherlands Journal of Agricultural Science 35, no. 4 (November 1, 1987): 537–40. http://dx.doi.org/10.18174/njas.v35i4.16714.
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Williams, Harry, Christian Messier, and Daniel D. Kneeshaw. "Effects of light availability and sapling size on the growth and crown morphology of understory Douglas-fir and lodgepole pine." Canadian Journal of Forest Research 29, no. 2 (February 1, 1999): 222–31. http://dx.doi.org/10.1139/x98-189.
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Information on the dynamics of sapling growth of Douglas-fir (Pseudotsuga menziesii var. glauca (Beissn.) Franco) and lodgepole pine (Pinus contorta Dougl. ex Loud. var. latifolia Engelm), two dominant species in the interior of British Columbia, Canada, is incomplete and thus the objective of this study was to understand how light availability and sapling size interact to influence their growth and crown morphology. In an undisturbed forest, 360 saplings were randomly selected in three light classes 0-15, 15-30, and >30% PPFD (photosynthetic photon flux density). A number of morphological and growth parameters were measured, including height and lateral branch growth. Douglas-fir had a more plastic crown morphology than lodgepole pine with its leader to lateral branch growth ratio, live crown depth, and number of branches increasing with increasing light class. Sapling size had little effect on morphological characteristics, but larger saplings of both species had greater absolute height growth and lateral branch growth than did smaller saplings. Both Douglas-fir and lodgepole pine were able to survive up to 50 years and attain a height of 3 m at less than 5% PPFD. These results further suggest that shade tolerance is greater on drier sites, although the mechanisms for such increases in tolerance are unknown. The ecological implications of these findings are discussed in a forestry context.
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Omdal, Daniel W., Charles G. Shaw, III, and William R. Jacobi. "Symptom expression in conifers infected with Armillaria ostoyae and Heterobasidion annosum." Canadian Journal of Forest Research 34, no. 6 (June 1, 2004): 1210–19. http://dx.doi.org/10.1139/x04-007.
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Crown symptoms and other aboveground variables were examined on 36 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco.) (40209 years old), 46 white fir (Abies concolor (Gord. & Glend.) Lindl.) (36165 years old), and 97 ponderosa pine (Pinus ponderosa Dougl. ex Laws.) (64220 years old) trees in northern New Mexico and southern Colorado. Root systems of all trees were excavated to determine extent of root disease. Symptoms observed on infected trees, including reductions in height growth, changes in foliage characteristics, and crown dieback, worsened as the number of infected roots increased. Trees with aboveground symptoms had a significantly higher (p < 0.05) number of infected lateral roots than trees without symptoms. In mixed conifer stands on the Archuleta Mesa, Colo., four qualitative crown symptoms were used to accurately detect Armillaria ostoyae (Romagn.) Herink and (or) Heterobasidion annosum (Fr.) Bref. infection of Douglas-fir (21/22, or 95%) and white fir (19/28, or 68%). Similarly, 61% (48/79) of the A. ostoyae infected ponderosa pine trees on the Jemez site, N.M., were detected using the qualitative Thomson vigor rating system. Discriminate analysis, using more thorough variables and analysis, resulted in correct infection classifications of 82%, 85%, and 78% for Douglas-fir, white fir, and ponderosa pine, respectively, suggesting that aboveground variables are reasonable indicators of root disease.
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Hughes, Thomas F., John C. Tappeiner, and Michael Newton. "Relationship of Pacific Madrone Sprout Growth to Productivity of Douglas-Fir Seedlings and Understory Vegetation." Western Journal of Applied Forestry 5, no. 1 (January 1, 1990): 20–24. http://dx.doi.org/10.1093/wjaf/5.1.20.
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Abstract We studied the development of Pacific madrone (Arbutus menziesii) sprout clumps of various initial densities and their effect on Douglas-fir (Pseudotsuga menziesii) seedling growth and understory vegetation. Five years after density treatments, average leaf area index (LAI) of 9-year-oldmadrone sprouts ranged from 3.6-1.0 m²/m² and total aboveground biomass from 25,630-8,390 kg/ha on the high- and low-density plots, respectively. Diameter of 9-year-old Douglas-fir was inversely related to madrone LAI and ranged from about 27 mm on the high-density plots to 54 mmin the absence of madrone. Analyses of diameter growth trends also indicated that, in the absence of madrone, Douglas-fir grew significantly (P = 0.001 to 0.023) faster than in other treatments. An index of shrub, forb, and grass density was inversely related to madrone LAI, suggesting thatunderstory species are quickly excluded from young madrone stands during secondary succession. We provide equations relating the 5-year growth of 9-year-old Douglas-fir to measures of madrone density and seedling size made when the plantation was 5 years old. West. J. Appl. For. 5(1):20-24.
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Drever, C. Ronnie, and Kenneth P. Lertzman. "Light-growth responses of coastal Douglas-fir and western redcedar saplings under different regimes of soil moisture and nutrients." Canadian Journal of Forest Research 31, no. 12 (December 1, 2001): 2124–33. http://dx.doi.org/10.1139/x01-149.
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We characterized the radial and height growth response to light for coastal Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco var. menziesii) and western redcedar (Thuja plicata Donn ex D. Don) saplings growing in sites of different regimes of soil moisture and nutrients on the east coast of Vancouver Island, British Columbia. We determined that at low light levels, site quality has little effect on the growth response of Douglas-fir saplings. At light levels above approximately 40 and 60% full sun, Douglas-fir saplings show statistically significant differences in height and radial growth, respectively, that reflect the differences in soil moisture and nutrient regimes of the sites we examined. Western redcedar approaches its maximum radial and height growth rates at about 30% full sun. Our data suggest that partial-cutting treatments need to create light environments greater than about 40% full sun to achieve growth that represents a high proportion of the site growing potential for Douglas-fir at full sun, while the high shade tolerance of western redcedar allows silvicultural treatments that retain a high amount of forest structure without compromising growth rates of young trees.
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Canaday, Christopher L. "COMPARISON OF INSECT FAUNA CAPTURED IN SIX DIFFERENT TRAP TYPES IN A DOUGLAS-FIR FOREST." Canadian Entomologist 119, no. 12 (December 1987): 1101–8. http://dx.doi.org/10.4039/ent1191101-12.
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AbstractInsects were sampled in a Douglas-fir forest in California to evaluate differences among inexpensive survey methods. Sampling was done with sweep nets and with window, sticky, light, suspended cone, and two kinds of yellow pan traps. Also examined were effects of trap location in the given tree and the following tree species: Douglas-fir (Pseudotsuga menziesii Franco), canyon live oak (Quercus chrysolepis Liebm.), tanoak (Lithocarpus densiflorus Rehd.), Pacific madrone (Arbutus menziesii Pursh.), and big-leaf maple (Acer macrophyllum Pursh.). Relative abundance and faunistic similarity of the 9662 insects caught varied greatly by trap type and little by tree species or trap location. Family-level taxonomic richness differed among the diverse trap types, tree species, and trap locations.
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Kašák, J., and J. Foit. "Double-spined bark beetle (Ips duplicatus) (Coleoptera: Curculionidae): a new host – Douglas fir (Pseudotsuga menziesii)." Journal of Forest Science 61, No. 6 (June 3, 2016): 274–76. http://dx.doi.org/10.17221/28/2015-jfs.
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