Artículos de revistas: "Douglas fir (Pseudotsuga menziesii Mirb. Franco)"

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Funk, A., T. A. D. Woods y Sarah J. Hopkinson. "Hormonema merioides n.sp., on Douglas-fir needles". Canadian Journal of Botany 63, n.º 9 (1 de septiembre de 1985): 1579–81. http://dx.doi.org/10.1139/b85-219.

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Hart, V., M. Nentvichová-Hartová y P. Tauchman. "Analysis of herbicide effects on Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) natural regeneration". Journal of Forest Science 56, No. 5 (28 de mayo de 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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Alfaro, René I. y Roy F. Shepherd. "Tree-Ring Growth of Interior Douglas-Fir After One Year's Defoliation by Douglas-Fir Tussock Moth". Forest Science 37, n.º 3 (1 de agosto de 1991): 959–64. http://dx.doi.org/10.1093/forestscience/37.3.959.

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Abstract Reductions in ring width of Douglas-fir, Pseudotsuga menziesii [Mirb.] Franco, trees defoliated for 1 year by the Douglas-fir tussock moth, Orgyia pseudotsugata (McDunnough), are reported. Trees were treated with a nuclear polyhedrosis virus, but the resultant epizootic which killed larvae and reduced defoliation took several weeks to develop and trees sustained varying degrees of damage. No negative effects of defoliation were noted in the year when feeding took place; on the contrary, a growth stimulation occurred. Defoliation levels above 50% resulted in growth reduction for 2 years following defoliation relative to nondefoliated trees. The implications of these growth changes for cost/benefit analysis of control options are discussed. For. Sci. 37(3):959-964.

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Mauer, O. y E. Palátová. " Root system development in Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) on fertile sites". Journal of Forest Science 58, No. 9 (23 de octubre de 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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de Kort, Ingrid. "Relationships Between Sapwood Amount, Latewood Percentage, Moisture Content and Crown Vitality of Douglas Fir, Pseudotsuga Menziesii". IAWA Journal 14, n.º 4 (1993): 413–27. http://dx.doi.org/10.1163/22941932-90000596.

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Relationships between sapwood amount, latewood percentage, moisture content and crown vitality were studied in 171 Douglas firs [Pseudotsuga menziesii (Mirb.) Franco] belonging to different vitality classes. The trees originated from 10 stands in the Netherlands varying in age from 25-70 years.

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Kaundun, Shiv Shankhar, Philippe Lebreton y Alain Bailly. "Needle flavonoid variation in coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) populations". Canadian Journal of Botany 76, n.º 12 (1 de diciembre de 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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Mondek, Jan y Martin Baláš. "Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) and its role in the Czech forests". Journal of Forest Science 65, No. 2 (5 de marzo de 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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Sychra, D. y O. Mauer. "Prosperity of Douglas fir (Pseudotsuga menziesii [Mirb.] Franco) plantations in relation to the shelter". Journal of Forest Science 59, No. 9 (29 de octubre de 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 y M. Zeman. "Economic Impact of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) production in the Czech Republic". Journal of Forest Science 60, No. 7 (5 de agosto de 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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El-Kassaby, Yousry A. y Hugh J. Barclay. "Cost of reproduction in Douglas-fir". Canadian Journal of Botany 70, n.º 7 (1 de julio de 1992): 1429–32. http://dx.doi.org/10.1139/b92-179.

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The balance between allocating energy resources to reproduction or growth has considerable theoretical interest. Conflicting ecological requirements and evolutionary pressures often necessitate a trade-off in energy allocation. We obtained measurements on seed-cone production and annual ring width of 365 Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) trees from 29 open-pollinated families for 8 years. Phenotypic, genetic, and environmental correlations were computed for seed-cone production and ring width for each year. Five of the eight environmental correlations were negative (range −0.077 to −0.305), reflecting the reality of the trade-off in physiological terms. Six of the eight genetic correlations were negative (range −0.199 to −0.776), indicating that a trade-off exists at the genetic level between energy allocation to reproduction and to somatic growth. These findings agree with the current theory of life-history evolution. Key words: Pseudotsuga menziesii, cone production, annual ring width, genetic correlation.

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Marshall, Valin G. y Hugh J. Barclay. "Response of young Douglas-fir to urea fertilizer applied on and off snow". Forestry Chronicle 70, n.º 3 (1 de junio de 1994): 294–98. http://dx.doi.org/10.5558/tfc70294-3.

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The effects of 200 kg N ha−1 applied as urea fertilizer on 50 cm of snow or on bare ground were studied in an 11-year-old Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) plantation on Vancouver Island. Analysis was done on all trees per plot and on 20 selected dominant trees per plot. Up to 2 years after fertilization, urea significantly increased absolute DBH increments over controls in all trees and the 20 selected trees per plot; response to fertilization on snow was equal to that on bare ground. Between the 3rd and 9th year following fertilization, mean DBH increments were not significantly different for any treatment. Four-year absolute volume increments were 63 and 87% greater than the controls for bare-ground and on-snow applications, respectively. A positive and quantitatively similar response is expected in wetter coastal Douglas-fir stands whether urea is applied on snow or under better conditions during other seasons. Key words: Forest fertilization, season of application, nitrogen, tree response, Pseudotsuga menziesii (Mirb.) Franco

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Kostic, Olga, Miroslava Mitrovic y 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, n.º 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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Podrázský, V., A. Martiník, K. Matějka y 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 (5 de agosto de 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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Anastasijevic, Nebojsa, Mirjana Ocokoljic y Vesna Vratusa. "Properties and variability of douglas-fir seedlings -Pseudotsuga menziesii (Mirb.) Franco-". Genetika 37, n.º 2 (2005): 113–19. http://dx.doi.org/10.2298/gensr0502113a.

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Based on the comparative morphophysiological analysis of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings, three half-sib lines from Quercetum farneto-cerris s.l. site, and three half-sib lines from Saliceto-Populeturn s.l. site, the data on seedling characteristics and variability of this cultivated species are discussed. The paper also ascertains the variability of seedling properties that affect mother tree selection and production technology of plant material of desired characteristics for the application in forestry and landscape architecture and horticulture.

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Osman, Khalid A. y Steven H. Sharrow. "Growth responses of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) to defoliation". Forest Ecology and Management 60, n.º 1-2 (agosto de 1993): 105–17. http://dx.doi.org/10.1016/0378-1127(93)90025-i.

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16

Ross, Darrell W. y Gary E. Daterman. "EFFICACY OF AN ANTIAGGREGATION PHEROMONE FOR REDUCING DOUGLAS-FIR BEETLE, DENDROCTONUS PSEUDOTSUGAE HOPKINS (COLEOPTERA: SCOLYTIDAE), INFESTATION IN HIGH RISK STANDS". Canadian Entomologist 127, n.º 6 (diciembre de 1995): 805–11. http://dx.doi.org/10.4039/ent127805-6.

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AbstractThe Douglas-fir beetle (Dendroctonus pseudotsugae) antiaggregation pheromone, 3-methylcyclohex-2-en-1-one (MCH), was applied to stands at high risk for infestation. The MCH was applied in a bubble capsule formulation to plots ranging from 2.1 to 2.6 ha in size at rates of 45–76 g/ha. Catches of Douglas-fir beetles in attractant-baited Lindgren funnel traps located at the plot centers were significantly lower on MCH-treated plots compared with untreated plots. In contrast, catches of the most abundant predator, Thanasimus undatulus (Say), were unaffected by the MCH treatment. The percentage of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] trees ≥20 cm dbh that were mass attacked was significantly lower on treated plots (0.2%) compared with untreated plots (8.5%). MCH alone was effective in reducing the probability of Douglas-fir beetle infestations occurring in high risk stands.

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Cruz-Nicolás, Jorge, J. Jesús Vargas-Hernández, Porfirio Ramírez-Vallejo y Javier López-Upton. "GENETIC DIVERSITY AND DIFFERENTIATION OF Pseudotsuga menziesii (Mirb.) Franco POPULATIONS IN MÉXICO". Revista Fitotecnia Mexicana 34, n.º 4 (30 de diciembre de 2011): 233. http://dx.doi.org/10.35196/rfm.2011.4.233.

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Mexican populations of Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] constitute valuable gene pools for conservation and breeding programs of this species. Genetic diversity and population divergence were estimated using 18 isozyme loci and samples from 11 natural Douglas-fir populations in México. Genetic diversity was high at the species level (83.3 % polymorphic loci and 2.9 alleles per locus), but low at the population level (28.3 % polymorphic loci and 1.52 alleles per locus), particularly for populations from central México. A high level of population differentiation was found (Fst = 0.298), indicating that each population shares only a small fraction of the genetic diversity within the species and that genetic drift might have an important role in shaping the structure of genetic diversity in these populations. Genetic distances among populations in the Sierra Madre Oriental were positively correlated with geographic distances (r = 0.849), but the association was not significant according to the Mantel test. Populations from northeastern México separated from all others, whereas population Mohinora from northwestern México, joined those from central México. These results emphasize the priority for in situ conservation of Douglas-fir populations in central México.

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Schaupp, Willis C. "HOST ASSOCIATIONS IN SYMPATRIC POPULATIONS OF CHORISTONEURA OCCIDENTALIS FREEMAN AND C. RETINIANA (WALSINGHAM) (LEPIDOPTERA: TORTRICIDAE) IN SOUTH-CENTRAL OREGON AT HIGH POPULATION DENSITIES". Canadian Entomologist 123, n.º 3 (junio de 1991): 713–15. http://dx.doi.org/10.4039/ent123713-3.

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Sympatric, synchronous populations of conifer-feeding Choristoneura (Lepidoptera: Tortricidae) occur in western North America (Powell 1980). Choristoneura occidentalis Freeman, the western spruce budworm, co-exists with C. retiniana, the Modoc budworm, in mixed stands of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, and true firs, Abies spp. Choristoneura occidentalis has brown larvae and a broad geographic distribution associated with one of its principle hosts, Douglas-fir (Stehr 1967). Larvae of C. retiniana are green and feed on true firs, particularly white fir, Abies concolor (Gord. & Glend.) Lindl. (Stehr 1967; Carolin et al. 1987).

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Thier, R. W. y Steve Patterson. "Mortality of Douglas-fir After Operational Semiochemical Baiting for Douglas-fir Beetle (Coleoptera: Scolytidae)". Western Journal of Applied Forestry 12, n.º 1 (1 de enero de 1997): 16–20. http://dx.doi.org/10.1093/wjaf/12.1.16.

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Abstract Effects of an operational application of synthetic Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) attractants applied to Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) trees have not been well documented. Baits, containing a 1:1 mixture of frontalin and alpha-pinene, were deployed over 64 acres in an area application at the rate of 2 baits/ac. Baited trees, and unbaited Douglas-firs surrounding the bait centers, were selected for measurements. All baited trees were attacked along with 42.3% of the surrounding unbaited Douglas-firs. Attacked trees were significantly larger than unattacked trees and were closer to the bait centers. The percentage of trees attacked was not influenced by cardinal direction from the bait center. Approximately 97% of the baited trees were either moderately or heavily attacked. Almost 60% of the moderately and heavily attacked unbaited Douglas-firs were within 33 ft of the bait centers. A model to predict probability of infestation of unbaited trees surrounding the bait center was developed. West. J. Appl. For. 12(1):16-20.

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Funk, A. "Monilia versiformia sp. nov. (Hyphomycetes) from a perennial Douglas-fir canker". Canadian Journal of Botany 65, n.º 1 (1 de enero de 1987): 23–25. http://dx.doi.org/10.1139/b87-003.

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Monilia versiformia sp. nov. is a pleoanamorphic fungus producing two types of blastoconidia, viz., monilioid chains of dark-colored, sphaeroid conidia and lunate, hyaline conidia produced singly on simple, conidiogenous hyphae. The chains are produced in great abundance, and as the conidia mature and become pigmented, the chains break down and form a sooty mass. The fungus was isolated from a perennial canker of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in British Columbia, Canada.

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Hagerman, Shannon M. y 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, n.º 6 (1 de junio de 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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Nemec, Amanda F. Linnell, Roberta Parish y James W. Goudie. "Modelling number, vertical distribution, and size of live branches on coniferous tree species in British Columbia". Canadian Journal of Forest Research 42, n.º 6 (junio de 2012): 1072–90. http://dx.doi.org/10.1139/x2012-060.

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A compound, nonhomogeneous Poisson process was used to model the number, vertical distribution, and size of branches on four coniferous tree species: 134 western hemlock ( Tsuga heterophylla (Raf.) Sarg.) on six sites, 45 amabilis fir ( Abies amabilis Douglas ex J. Forbes) (three sites), 60 lodgepole pine ( Pinus contorta var. latifolia Engelm. ex S. Watson) (six sites), and 60 white spruce ( Picea glauca (Moench) Voss) trees (five sites) and two varieties: 66 coastal Douglas-fir ( Pseudotsuga menziesii var. menziesii (Mirb.) Franco) (five sites) and 50 interior Douglas-fir ( Pseudotsuga menziesii var. glauca (Mayr) Franco) (four sites). Branches of these species are typically more or less clustered and have a characteristic, nonuniform vertical distribution along annual shoots. Total number and relative positions of clusters varied with shoot age. Clustering patterns in three of four species and two varieties appeared to scale proportionally with shoot length. However, in lodgepole pine, which has fewer clusters per metre and more branches per cluster, the vertical distribution of clusters along shoots ≤5 years old was consistent with a gamma-Poisson model but converged to a nonhomogeneous Poisson process model in shoots >5 years old. Separate mixed-effect regression models were developed for each species relating length and diameter of live branches to tree (crown), shoot, and branch (cluster) predictor variables.

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Shore, T. L., L. Safranyik, W. G. Riel, M. Ferguson y J. Castonguay. "EVALUATION OF FACTORS AFFECTING TREE AND STAND SUSCEPTIBILITY TO THE DOUGLAS-FIR BEETLE (COLEOPTERA: SCOLYTIDAE)". Canadian Entomologist 131, n.º 6 (diciembre de 1999): 831–39. http://dx.doi.org/10.4039/ent131831-6.

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AbstractTree and site characteristics were compared between 19 groups of Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco (Pinaceae), infested by Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, and 19 uninfested groups to identify individual or combinations of characteristics associated with Douglas-fir beetle attacks. Of the tree characteristics, diameter, height, age, phloem thickness, bark thickness, and a standardized variable consisting of diameter divided by the last 10 years growth rate (DBHTYG) showed significant differences. None of the site characteristics showed significant differences between infested and uninfested areas. Two models, identified through discriminant analysis, placed 84 and 87% of the data in the correct infestation groups. These models included the variables diameter, height, phloem thickness, aspect, and DBHTYG in various combinations. The results were confirmed using a jackknifed cross-validation approach. These variables have potential for use in the development of a biological process model of tree and stand susceptibility to the Douglas-fir beetle.

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Čater, Matjaž. "Microsites Influence the Light Response of Young Douglas-Fir (Pseudotsuga menziesii (Mirb.) Franco)". Forests 12, n.º 6 (27 de mayo de 2021): 687. http://dx.doi.org/10.3390/f12060687.

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Two comparable sites with uneven-aged mixed forest stands with more than 20% Douglas-fir in the growing stock at an altitude of 650 m a.s.l. were selected. The physiological response of young trees to different light intensities was measured during the main growing season in three consecutive years, and four different light categories, which were determined from hemispherical photographs. The four light intensity categories were defined according to Indirect Site Factor (ISF%): in the open (A-ISF > 35%), at the outer forest edge (B-25% < ISF < 35%), at the inner forest edge (C-15% < ISF < 25%), and under complete canopy under mature forest stand (D-ISF < 15%). Climate data were obtained from the Royal Netherlands Meteorological Institute ‘Climate Explorer’ website (http://climexp.knmi.nl). For the intensive micrometeorological observations, four monitoring sites were established along the elevation gradient at each site during summer and late fall to record relative humidity (RH%) and temperature (°C) with a 30 min recording interval sequence. Measured assimilation responses (A) and light use efficiency () at one site followed the expected pattern, while humidity combined with microsite conditions proved significant in explaining the specific response of young Douglas-fir to the different light intensity at the other site. For higher survival and optimal future development of Douglas-fir in the changing environment, microsites with higher capacity for storage moisture and favorable microclimate should generally be preferred to exposed and dry sites.

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Levanič, Tom y Hana Štraus. "Effects of Climate on Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) Growth Southeast of the European Alps". Plants 11, n.º 12 (14 de junio de 2022): 1571. http://dx.doi.org/10.3390/plants11121571.

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Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is a non-native tree species in Slovenia with the potential to partially replace Norway spruce in our native forests. Compared to spruce, it has several advantages in terms of volume growth, wood quality and tolerance to drought. This is important given the changing climate in which spruce is confronted with serious problems caused by increasing temperatures and drought stress. At three sites (one on non-carbonate bedrock and deep soils, and two on limestone with soil layers of varying depths), 20 Douglas-fir and 20 spruce per site were sampled in order to compare their radial growth response to climate and drought events. The radial growth of Douglas-fir exceeds that of spruce by about 20% on comparable sites. It is more responsive to climate than spruce. Above-average temperatures in February and March have a significant positive effect on the radial growth of Douglas-fir. In recent decades, above-average summer precipitation has also had a positive influence on the radial growth of Douglas-fir. Compared to spruce, Douglas-fir is less sensitive to extreme drought events. Our results indicate that Douglas-fir may be a good substitute for spruce in semi-natural managed forest stands in Slovenia. The planting of Douglas-fir should be allowed in Slovenian forests, but the proportion of it in forest stands should be kept lower than is the case with spruce today.

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Giannini, R., M. Lambardi y G. G. Vendramin. "SOME OBSERVATIONS ON GRAFT INCOMPATIBILITY IN DOUGLAS-FIR (PSEUDOTSUGA MENZIESII MIRB. FRANCO) (*)". Acta Horticulturae, n.º 227 (septiembre de 1988): 84–86. http://dx.doi.org/10.17660/actahortic.1988.227.8.

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27

WARREN, C. R., G. J. ETHIER, N. J. LIVINGSTON, N. J. GRANT, D. H. TURPIN, D. L. HARRISON y T. A. BLACK. "Transfer conductance in second growth Douglas-fir (Pseudotsuga menziesii (Mirb.)Franco) canopies". Plant, Cell & Environment 26, n.º 8 (26 de junio de 2003): 1215–27. http://dx.doi.org/10.1046/j.1365-3040.2003.01044.x.

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28

Solheim, Halvor y Paal Krokene. "Growth and virulence of Ceratocystis rufipenni and three blue-stain fungi isolated from the Douglas-fir beetle". Canadian Journal of Botany 76, n.º 10 (1 de octubre de 1998): 1763–69. http://dx.doi.org/10.1139/b98-146.

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Blue-stain fungi were isolated from the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, and from Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco, colonized by the beetle. Growth of the three most commonly isolated blue-stain fungi (Leptographium abietinum (Peck) Wingfield, Ophiostoma europhioides (Wright & Cain) Solheim, Ophiostoma pseudotsugae (Rumbold) von Arx), and Ceratocystis rufipenni Wingfield, Harrington, & Solheim, an important associate of the spruce beetle, Dendroctonus rufipennis (Kirby), was studied in sapwood and phloem of live Douglas-fir trees, on malt agar, and on malt agar under oxygen-deficient conditions. The two Ophiostoma species grew better in the phloem and induced longer phloem necroses than the other fungi. Ceratocystis rufipenni and O. europhioides grew better in the sapwood and induced deeper sapwood occlusion. All fungi were relatively fast growing on malt agar, with O. pseudotsugae growing fastest and L. abietinum, slowest. Growth of C. rufipenni and O. europhioides was inhibited less by low oxygen levels than the other fungi, and this may explain why these two fungi were better able to colonize live sapwood.Key words: Ceratocystis rufipenni, Dendroctonus pseudotsugae, Douglas-fir, Leptographium abietinum, Ophiostoma europhioides, Ophiostoma pseudotsugae.

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Newton, Michael y Elizebeth C. Cole. "A Sustained-Yield Scheme for Old-Growth Douglas-fir". Western Journal of Applied Forestry 2, n.º 1 (1 de enero de 1987): 22–25. http://dx.doi.org/10.1093/wjaf/2.1.22.

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Abstract From analysis of two Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands, 120 and 140 years old, we conclude that managed stands can meet established criteria for old-growth Douglas-fir and simultaneously produce near-maximum yields of good-quality timber. With the management approach outlined here, average annual volume growth may approach that of shorter-rotation culture, but in logs of a size and quality normally found only in older stands, and with minimal impact on high-risk watersheds or old-growth habitat. This possibility encourages development of silvicultural systems that can achieve such goals in a variety of timber types. West. J. Appl. For. 2:22-25, Jan. 1987.

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Staudhammer, Christie y Valerie LeMay. "Height prediction equations using diameter and stand density measures". Forestry Chronicle 76, n.º 2 (1 de abril de 2000): 303–9. http://dx.doi.org/10.5558/tfc76303-2.

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Height equations for western hemlock (Tsuga heterophylla (Raf.) Sarg.), western red cedar (Thuja plicata Donn), Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), and alder (Alnus rubra Bong. and Alnus tenuifolia Nutt.) were fitted using dbh as the predictor variable. A simple, non-linear equation gave very similar results to the Weibull distribution, except for hemlock, which was better modelled using the more flexible Weibull distribution function. Introducing stand density variables into the base equations resulted in increased accuracy for predicting heights of alder. Smaller improvements were found for Douglas-fir, cedar, and hemlock. Key words: estimating height, Coastal BC, Weibull estimation, stand density measures

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Smolnikar, Peter, Robert Brus y Kristjan Jarni. "Differences in Growth and Log Quality of Douglas-Fir (Pseudotsuga menziesii (Mirb.) Franco) Provenances". Forests 12, n.º 3 (2 de marzo de 2021): 287. http://dx.doi.org/10.3390/f12030287.

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Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is a non-native conifer from western North America that was introduced into European forests at the end of the 19th century. Plantations of Douglas-fir in Europe have shown good performance, quality, and resilience to exacerbating climatic conditions. However, all these qualities strongly depend on provenance. A total of 1061 surviving trees of fifteen different Douglas-fir provenances were measured in a Slovenian provenance trial that was established within the framework of the 1966/1967 IUFRO seed collection program. We found significant differences among provenances with respect to survival rate, growth performance, and log quality. The total recorded yield of the 46-year-old stand was 602.9 m3/ha, and the average survival rate was 43%. The correlation of juvenile tree heights in 1985 and their average breast height diameters in 2017 is positive and significant. Based on vitality and diameter, the best performing provenances were Yelm and Cathlamet. The provenance with the best log quality assessed through branchiness is Jefferson (Olympic Peninsula, western Washington). All the most promising provenances for western Slovenia (Central Europe) originate from the low-altitude western coast of Washington (WACO), with the Cathlamet provenance showing the best combination of good growth, survival rate, and log quality.

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Coops, Nicholas C., Robbie A. Hember y Richard H. Waring. "Assessing the impact of current and projected climates on Douglas-Fir productivity in British Columbia, Canada, using a process-based model (3-PG)". Canadian Journal of Forest Research 40, n.º 3 (marzo de 2010): 511–24. http://dx.doi.org/10.1139/x09-201.

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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.

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Muller, C., E. Falleri, E. Laroppe y M. Bonnet-Masimbert. "Drying and storage of prechilled Douglas fir, Pseudotsuga menziesii, seeds". Canadian Journal of Forest Research 29, n.º 2 (1 de febrero de 1999): 172–77. http://dx.doi.org/10.1139/x98-193.

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Douglas fir, Pseudotsuga menziesii (Mirb.) Franco, seeds exhibit relative dormancy as they do not germinate at suboptimal temperature (15°C), whereas at optimal temperature (20°C) some germination occurred. Thus, germination at 15°C was chosen to estimate dormancy release. In the first experiment, seeds were prechilled at 32% moisture content (MC) for 0-34 weeks at 3°C. Long chilling treatments enhanced germinability and, more markedly, germination speed both at 20°C and at 15°C. Seeds pretreated for the longest periods were then dried to 6.7% MC and stored up to 6 months without any detrimental effect on germination at 15°C. In the second experiment, seeds from a second seedlot were prechilled for 18 weeks and then stored at three different MCs over a period of 17 months. Seeds stored at the lowest MC (6.7%) germinated fastest and to the highest percentage both at 15 and 20°C. In the nursery, seedling emergence tests confirmed results from this experiment. In most cases, comparisons between seeds prechilled at controlled MC before storage and those stratified with the traditional method resulted in better performance of the first ones, both in the laboratory and in the nursery.

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Puettmann, Klaus J., David W. Hann y David E. Hibbs. "Evaluation of the Size-Density Relationships for Pure Red Alder and Douglas-Fir Stands". Forest Science 39, n.º 1 (1 de febrero de 1993): 7–27. http://dx.doi.org/10.1093/forestscience/39.1.7.

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Abstract Size-density trajectories were developed for pure red alder (Alnus rubra Bong) and Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) stands with quadratic mean diameter of the stand as the tree-size variable. The resulting self-thinning or maximum size-density line for red alder had a steeper slope (-0.64) than that for Douglas-fir (-0.52). The assumption of a common slope for all species is therefore not supported by our study. For red alder, the shape of the size-density trajectory and the elevation of the maximum line were not influenced by initial density or stand origin. Red alder and Douglas-fir mortality started at a relative density of 44% and 58%, respectively. FOR. SCI. 39(1):7-27.

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Petkova, K., M. Georgieva y M. Uzunov. "Investigation of Douglas-fir provenance test in North-Western Bulgaria at the age of 24 years". Journal of Forest Science 60, No. 7 (5 de agosto de 2014): 288–96. http://dx.doi.org/10.17221/12/2014-jfs.

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A comparative analysis of growth rate and health condition of 54 Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) provenances was conducted at the age of 24 years. The provenance test was established in 1990 with 3-year-old (3+0) seedlings planted in a 2 × 2 m plot design and two replications. The provenances which were studied originated from North America and were separated into coastal, continental and Western Cascade groups. In 2011 the growth rate was studied in terms of height, diameter at breast height and stem volume. The health condition was assessed by the evidence of symptoms and degree of defoliation caused by the fungi Phaeocryptopus gaeumannii (Rohde) Petrak and Rhabdocline pseudotsugae (Syd.). The provenances Newhalem, Darrington, Idanha and Bremerton were characterized by the most rapid growth, highest productivity and lower susceptibility to both fungal pathogens. These Douglas-fir provenances were recommended for future afforestation in Bulgaria. Ten continental provenances should be excluded from future afforestation because of their lowest growth rate and productivity and high susceptibility to P. gaeumannii and R. pseudotsugae.  

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Daoudi, EL-Hassania y Marc Bonnet-Masimbert. "Polyamines conjuguées et différenciation florale chez le sapin de Douglas (Pseudotsuga menziesii (Mirb.) Franco)". Canadian Journal of Botany 76, n.º 5 (1 de mayo de 1998): 782–90. http://dx.doi.org/10.1139/b98-044.

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To characterize as early as possible the status of flowering differentiation in Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco), the variation of bound or conjugated polyamines is studied in the shoots of young plants (6 years old) during the period covering flowering initiation (between 30 and 75 days after bud burst). These compounds are also quantified in sexual and vegetative buds. The quantitative effects of treatments susceptible to stimulate the flowering (application of gibberellins and (or) calcium nitrate) on the level of conjugated polyamines are investigated in the shoots. The combination of gibberellins to calcium nitrate application strongly increases the flowering. Conjugated polyamines are particularly abundant in sexual buds and in the shoots of flowering plants. Sexual buds are also characterized by a ratio of conjugated putrescine to conjugated spermidine about four to six times higher than in vegetative buds. The accumulation of conjugated polyamines in the shoots accompanies bud sexualization, which suggests that conjugated polyamines may constitute potential markers of floral initiation in Douglas-fir.Key words: floral induction, flowering marker, conjugated polyamines, Douglas-fir.

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Fontes, L. "Modelling dominant height growth of Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) in Portugal". Forestry 76, n.º 5 (1 de mayo de 2003): 509–23. http://dx.doi.org/10.1093/forestry/76.5.509.

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38

Schütz, J. P. y A. Pommerening. "Can Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) sustainably grow in complex forest structures?" Forest Ecology and Management 303 (septiembre de 2013): 175–83. http://dx.doi.org/10.1016/j.foreco.2013.04.015.

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39

Lavadinović, Vera, Vukan Lavadinović, Zoran Poduška y Milan Kabiljo. "Variability of the width of Douglas-fir (Pseudotsuga menziessii /Mirb./Franco) needles in provenance tests". Sustainable Forestry: Collection, n.º 73-74 (2016): 1–9. http://dx.doi.org/10.5937/sustfor1673001l.

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Introduced tree species which have a wide natural range of distribution should be tested in experiments with different provenances. Douglas-fir is a very productive conifer species in its natural forest stands of America and Canada. Because of its high value, it is very popular in the countries of Europe and New Zealand as a conifer species suitable for reforestation. Its genetics and ecological adaptability can be confirmed by the investigations of its variable morphological traits, which is the aim of this research. Needle characteristics and needle morphology play a very important role in the performance of plant functions. Needle structure has a great influence on the plant life-cycle and their resistance to water loss, temperature and CO2 levels. The characteristics and morphology of needles were studied in order to determine whether there are differences between the provenances. Two experimental plots with twenty Douglas-fir provenances originally from North America were established in Serbia. A two-way analysis of variance was aimed at a closer study of the effects of the interaction of the site conditions of Douglas-fir provenances in the test locations in Serbia on the morphological traits of the needles.

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Pyles, Marvin R. y Joan Stoupa. "Load-Carrying Capacity of Second-Growth Douglas-Fir Stump Anchors". Western Journal of Applied Forestry 2, n.º 3 (1 de julio de 1987): 77–80. http://dx.doi.org/10.1093/wjaf/2.3.77.

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Abstract In order to quantify the stump anchor capacity of small second-growth Douglas-fir (Pseudotsuga menziesii [Mirb]. Franco) trees, load tests to failure were conducted on 18 stumps from trees 7 to 16.5 in dbh. The tests produced ultimate loads that varied as the square of the tree diameter. However, the ultimate load typically occurred at stump system deformations that were far in excess of that which would be considered failure of a stump anchor. A hyperbolic equation was used to describe the load-deformation behavior of each stump tested and was generalized to describe all the test results. West. J. Appl. For. 2(3):72-80, July 1987.

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Riitters, Kurt H. y David A. Perry. "Early Genetic Evaluation of Open-Pollinated Douglas-Fir Families". Forest Science 33, n.º 2 (1 de junio de 1987): 577–82. http://dx.doi.org/10.1093/forestscience/33.2.577.

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Abstract In a test of early genetic evaluation of the growth potential of 14 families of open-pollinated Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), measures of growth and phenology of seedlings grown in a coldframe were correlated with height of saplings in evaluation plantations at 9, 12, and 15 years. Fifteen-year height was most strongly correlated with measures of seedling budset (r = -0.57), height (r = 0.54), and branchiness (r = -0.53). Seedling growth and phenology values generally were poorly correlated with seed weight; however, seedling-sapling correlations were related to seedling-seed weight correlations. Seedling-sapling correlations improved with sapling age from 9 to 15 years. For. Sci. 33(2):577-582.

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Selosse, M. A., D. Bouchard, F. Martin y F. Le Tacon. "Effect of Laccaria bicolor strains inoculated on Douglas-fir (Pseudotsuga menziesii) several years after nursery inoculation". Canadian Journal of Forest Research 30, n.º 3 (1 de marzo de 2000): 360–71. http://dx.doi.org/10.1139/x99-221.

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In the Saint-Brisson experiment conducted in central France, the American strain of the ectomycorrhizal fungus Laccaria bicolor (Maire) P.D. Orton S238N and the French strain L. bicolor 81306 inoculated on containerized Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) seedlings increased by 60% the total volume of wood produced 8 years after outplanting as compared with uninoculated but naturally mycorrhizal trees. The two strains introduced 10 years before in the inoculated plots are still present and dominant; they did not prevent the colonization of Douglas-fir roots by naturally occurring ectomycorrhizal fungi but allowed for the establishment of a very diversified symbiotic microflora. Eight to 12 years after outplanting, all the Douglas-fir plots were colonized by Laccaria laccata (Scop.:Fr.) Cooke or L. bicolor strains, as well as some other species, independently of the nursery treatments. With one exception in one plot, the presence of indigenous genets in the control treatments may have prevented the vegetative colonization of the inside of the noninoculated plots by the two introduced strains.

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Campbell, Bruce C. y Patrick J. Shea. "A SIMPLE STAINING TECHNIQUE FOR ASSESSING FEEDING DAMAGE BY LEPTOGLOSSUS OCCIDENTALIS HEIDEMANN (HEMIPTERA: COREIDAE) ON CONES". Canadian Entomologist 122, n.º 5 (octubre de 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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Prenzel, Björn G., William G. Laidlaw y Hal Wieser. "WITHIN-TREE DYNAMICS OF MASS ATTACK BY DENDROCTONUS PSEUDOTSUGAE (COLEOPTERA: SCOLYTIDAE) ON ITS HOST". Canadian Entomologist 131, n.º 5 (octubre de 1999): 635–43. http://dx.doi.org/10.4039/ent131635-5.

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AbstractThe within-tree scale dynamics of mass attack by the Douglas-fir beetle, Dendroctonus pseudotsugae Hopkins, on its host were investigated and quantified. Seven similarly sized Douglas-fir, Pseudotsuga menziesii (Mirb.) Franco (Pinaceae), infested as part of several pheromone-induced infestations, were monitored over an entire attack season. Ninety percent of the attacks on mass-attacked trees occurred within 3 weeks of colonization; the remaining 10% occurred gradually over the remaining 7 weeks of the attack season. Vertical attack distribution followed a Gaussian form that shifted upwards on the bole with increasing attack density. The change in attack pattern associated with increasing attack density was investigated for the central vertical portion of the bole, where most attacks occurred, and where the vertical pattern was least variable. At low density, attacks were randomly distributed. As density increased, the distance between attacks decreased, eventually resulting in a uniform distribution.

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Mazzola, M. y J. F. Costante. "Efficacy of BA For the Promotion of Lateral Bud Formation on Douglas-fir and Colorado Blue Spruce". HortScience 22, n.º 2 (abril de 1987): 234–35. http://dx.doi.org/10.21273/hortsci.22.2.234.

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Abstract A whole-tree foliar application of BA at a concentration of 1000 ppm increased lateral bud density on douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] but not on Colorado blue spruce (Picea pungens Englm.) when treated ≈6 weeks after budbreak. A single BA application made at the same time, but only to the terminal leader, was not effective in increasing overall lateral bud density on either the terminal or lateral branches of either species. Lammas shoots formed on all trees that received whole-tree applications of BA. Bud formation on lammas shoots appeared normal for douglas-fir but uncharacteristic for Colorado blue spruce. Chemical names used: N- (phenylmethyl)-lH-purin-6-amine (BA).

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LeDoux, Chris B., Roger D. Fight y Tom L. Ortman. "Stump-to-Truck Cable Logging Cost Equations for Young-Growth Douglas-fir". Western Journal of Applied Forestry 1, n.º 1 (1 de enero de 1986): 19–22. http://dx.doi.org/10.1093/wjaf/1.1.19.

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Abstract Logging cost simulators and data from logging cost studies have been assembled and converted into a series of equations that can be used to estimate the cost of logging young-growth coastal Douglas-fir. (Pseudotsuga menziesii [Mirb.] Franco var. menziesii) in mountainous terrain of the Pacific Northwest. These equations were developed for two small cable yarders and one medium-sized yarder and are applicable for harvests of timber from 6 to 24 inches in diameter on slopes of 10 to 50%. Cost components can be easily Calculated on a hand calculator. A computer program that can be adapted to many desktop computers and that will calculate the total stump-to-truck logging cost for a specified set of logging conditions is also available. West. J. Appl. For. 1:19-21, Jan. 1986.

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Rappaport, Nancy G. y David L. Wood. "PITYOPHTHORUS ORARIUS BRIGHT (COLEOPTERA: SCOLYTIDAE) IN A NORTHERN CALIFORNIA DOUGLAS-FIR SEED ORCHARD: EFFECT OF CLONE, TREE VIGOR, AND CONE CROP ON RATE OF ATTACK". Canadian Entomologist 126, n.º 5 (octubre de 1994): 1111–18. http://dx.doi.org/10.4039/ent1261111-5.

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AbstractThe geographic range of the Douglas-fir twig beetle, Pityophthorus orarius Bright, was extended beyond the original provenance of southern British Columbia to northern California. A survey of 457 Douglas-fir [Pseudotsuga menziesii (Mirb.) Franco] trees in 1985 revealed that those with heavy cone crops were more likely to be infested by twig beetles than were those with a light crop. Furthermore, attack rates differed among clones. A second survey done in 1987 confirmed the importance of clone and cone crop in attack rate. In this survey, stressed trees were attacked at a higher rate than unstressed trees. Beetle distributions appeared clumped in both surveys, possibly because of semio-chemicals or oviposition behavior.

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White, Timothy L. "Drought Tolerance of Southwestern Oregon Douglas-Fir". Forest Science 33, n.º 2 (1 de junio de 1987): 283–93. http://dx.doi.org/10.1093/forestscience/33.2.283.

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Abstract Seedlings from two open-pollinated families of Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) from each of 35 seed sources in southwestern Oregon were tested for their ability to survive simulated drought in growth room, greenhouse, and coldframe test environments. Generally, seedlings from seed sources originating from higher elevations and, to a lesser extent, from drier sites, were more drought tolerant. Seedlings from drought-tolerant sources tended to have earlier bud-set, smaller initial height, and less winter injury. The main selective force leading to earlier bud-set and smaller height growth appeared to be the colder temperature regime associated with higher elevations. Seedlings from high elevations entered dormancy sooner and were better able to survive the imposed drought. Implications for seed transfer and for breeding for drought-tolerant genotypes in southwestern Oregon are discussed. For. Sci. 33(2):283-293.

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Hood, Sharon y Barbara Bentz. "Predicting postfire Douglas-fir beetle attacks and tree mortality in the northern Rocky Mountains". Canadian Journal of Forest Research 37, n.º 6 (junio de 2007): 1058–69. http://dx.doi.org/10.1139/x06-313.

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Douglas-fir ( Pseudotsuga menziesii (Mirb.) Franco) were monitored for 4 years following three wildfires. Logistic regression analyses were used to develop models predicting the probability of attack by Douglas-fir beetle ( Dendroctonus pseudotsugae Hopkins, 1905) and the probability of Douglas-fir mortality within 4 years following fire. Percent crown volume scorched (crown scorch), cambium injury, diameter at breast height (DBH), and stand density index for Douglas-fir were most important for predicting Douglas-fir beetle attacks. A nonlinear relationship between crown scorch and cambium injury was observed, suggesting that beetles did not preferentially attack trees with both maximum crown scorch and cambium injury, but rather at some intermediate level. Beetles were attracted to trees with high levels of crown scorch, but not cambium injury, 1 and 2 years following fire. Crown scorch, cambium injury, DBH, and presence/absence of beetle attack were the most important variables for predicting postfire Douglas-fir mortality. As DBH increased, the predicted probability of mortality decreased for unattacked trees but increased for attacked trees. Field sampling suggested that ocular estimates of bark char may not be a reliable predictor of cambium injury. Our results emphasize the important role of Douglas-fir beetle in tree mortality patterns following fire, and the models offer improved prediction of Douglas-fir mortality for use in areas with or without Douglas-fir beetle populations.

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Massicotte, H. B., R. Molina, L. E. Tackaberry, J. E. Smith y 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, n.º 8 (21 de noviembre de 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.

Artículos de revistas sobre el tema "Douglas fir (Pseudotsuga menziesii Mirb. Franco)"

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