The Experts below are selected from a list of 183 Experts worldwide ranked by ideXlab platform
Randy Molina - One of the best experts on this subject based on the ideXlab platform.
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Arbutus Menziesii ericaceae facilitates regeneration dynamics in mixed evergreen forests by promoting mycorrhizal fungal diversity and host connectivity
American Journal of Botany, 2012Co-Authors: Peter G Kennedy, Dylan P Smith, Tom R Horton, Randy MolinaAbstract: Premise of study: In the mixed evergreen forests in the western United States, Arbutus Menziesii is able to quickly resprout following disturbance and, as such, act as a nurse tree during forest regeneration. The mechanism for this nurse tree effect has frequently been ascribed to mycorrhizal fungi, but no detailed molecular-based studies of the mycorrhizal fungal communities associated with A. Menziesii roots have yet been conducted. Methods: We examined the structure of the mycorrhizal fungal communities associated with A. Menziesii in varying forest types and seasons and assessed the potential for common mycelial networks between A. Menziesii and Pinaceae hosts, particularly Pseudotsuga Menziesii . Study sites were located in the Klamath-Siskyou region in southern Oregon, United States. Molecular approaches were used to identify the mycorrhizal fungi (ITS rDNA) and plant hosts ( trnL cDNA). Key results: Arbutus Menziesii hosts a highly diverse mycorrhizal fungal community with similar composition to communities found on other angiosperm and Pinaceae hosts. Phylogenetic analyses of the mycorrhizal genus Piloderma revealed that host species and geographic location had little effect on fungal taxon relatedness. Multihost fungal taxa were signifi cantly more frequent and abundant than single-host fungal taxa, and there was high potential for the formation of common mycelial networks with P. Menziesii . Conclusions: Our results suggest A. Menziesii is a major hub of mycorrhizal fungal diversity and connectivity in mixed evergreen forests and plays an important role in forest regeneration by enhancing belowground resilience to disturbance.
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Diversity and host specificity of ectomycorrhizal fungi retrieved from three adjacent forest sites by five host species
Botany, 1999Co-Authors: Hugues B. Massicotte, Randy Molina, Jane E Smith, Linda E. Tackaberry, Michael P. AmaranthusAbstract: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 hos...
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biology of the ectomycorrhizal genus rhizopogon iii influence of co cultured conifer species on mycorrhizal specificity with the arbutoid hosts arctostaphylos uva ursi and Arbutus Menziesii
New Phytologist, 1997Co-Authors: Randy Molina, Jane E Smith, Donaraye Mckay, L H MelvilleAbstract:Seedlings of Pseudotsuga Menziesii (Mirb.) Franco, Pinus ponderosa Dougl. ex Laws, Arbutus Menziesii Pursh., and cuttings of Arctostaphylos uva-ursi (L.) Spreng were grown in monoculture and in conifer-hardwood dual-culture combinations in the glasshouse and inoculated with spore slurries of six Rhizopogon species. The primary objectives were to assess and compare the pattern of host specificity between symbionts and to study the influence of co-cultured plants on ectomycorrhiza development. The Rhizopogon spp. ranged from genus-specific to multiple-host compatible. In monoculture, four Rhizopogon sp. (R. ellenae Smith, R. occidentalis Zeller & Dodge, R. smithii Hosford and R. subcaerulescens Smith) formed ectomycorrhizas with Pinus ponderosa, and two Rhizopogon sp. (R. parksii Smith and R. vinicolor Smith) formed ectomycorrhizas with Pseudotsuga Menziesii. None of the fungi tested developed ectomycorrhizas on Arbutus Menziesii or Arctostaphylos uva-ursi in monoculture. In dual culture, three of the four Rhizopogon species (R. ellenae, R. occidentalis and R. subcaerulescens) that formed ectomycorrhizas on Pinus ponderosa, formed some ectomycorrhizas on Arbutus Menziesii and Arctostaphylos uva-ursi. Rhizopogon parksii and R. vinicolor only formed ectomycorrhizas on Pseudotsuga Menziesii.
L H Melville - One of the best experts on this subject based on the ideXlab platform.
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biology of the ectomycorrhizal genus rhizopogon iii influence of co cultured conifer species on mycorrhizal specificity with the arbutoid hosts arctostaphylos uva ursi and Arbutus Menziesii
New Phytologist, 1997Co-Authors: Randy Molina, Jane E Smith, Donaraye Mckay, L H MelvilleAbstract:Seedlings of Pseudotsuga Menziesii (Mirb.) Franco, Pinus ponderosa Dougl. ex Laws, Arbutus Menziesii Pursh., and cuttings of Arctostaphylos uva-ursi (L.) Spreng were grown in monoculture and in conifer-hardwood dual-culture combinations in the glasshouse and inoculated with spore slurries of six Rhizopogon species. The primary objectives were to assess and compare the pattern of host specificity between symbionts and to study the influence of co-cultured plants on ectomycorrhiza development. The Rhizopogon spp. ranged from genus-specific to multiple-host compatible. In monoculture, four Rhizopogon sp. (R. ellenae Smith, R. occidentalis Zeller & Dodge, R. smithii Hosford and R. subcaerulescens Smith) formed ectomycorrhizas with Pinus ponderosa, and two Rhizopogon sp. (R. parksii Smith and R. vinicolor Smith) formed ectomycorrhizas with Pseudotsuga Menziesii. None of the fungi tested developed ectomycorrhizas on Arbutus Menziesii or Arctostaphylos uva-ursi in monoculture. In dual culture, three of the four Rhizopogon species (R. ellenae, R. occidentalis and R. subcaerulescens) that formed ectomycorrhizas on Pinus ponderosa, formed some ectomycorrhizas on Arbutus Menziesii and Arctostaphylos uva-ursi. Rhizopogon parksii and R. vinicolor only formed ectomycorrhizas on Pseudotsuga Menziesii.
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iii influence of co cultured conifer species on mycorrhizal specificity with the arbutoid hosts arctostaphylos uva ursi and Arbutus Menziesii
1997Co-Authors: Randy M Olina, Ane J E S Mith, L H MelvilleAbstract:summary Seedlings of Pseudotsuga Menziesii (Mirb.) Franco, Pinus ponderosa Dougl. ex Laws, Arbutus Menziesii Pursh., and cuttings of Arctostaphylos uva-ursi (L.) Spreng were grown in monoculture and in conifer-hardwood dual-culture combinations in the glasshouse and inoculated with spore slurries of six Rhizopogon species. The primary objectives were to assess and compare the pattern of host specificity between symbionts and to study the influence of co-cultured plants on ectomycorrhiza development. The Rhizopogon spp. ranged from genus-specific to multiple-host compatible. In monoculture, four Rhizopogon sp. (R. ellenae Smith, R. occidentalis Zeller & Dodge, R. smithii Hosford and R. subcaerulescens Smith) formed ectomycorrhizas with Pinus ponderosa, and two Rhizopogon sp. (R. parksii Smith and R. vinicolor Smith) formed ectomycorrhizas with Pseudotsuga Menziesii. None of the fungi tested developed ectomycorrhizas on Arbutus Menziesii or Arctostaphylos uva-ursi in monoculture. In dual culture, three of the four Rhizopogon species (R. ellenae, R. occidentalis and R. subcaerulescens) that formed ectomycorrhizas on Pinus ponderosa, formed some ectomycorrhizas on Arbutus Menziesii and Arctostaphylos uva-ursi. Rhizopogon parksii and R. vinicolor only formed ectomycorrhizas on Pseudotsuga Menziesii.
Jane E Smith - One of the best experts on this subject based on the ideXlab platform.
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Mycorrhiza-like interaction by Morchella with species of the Pinaceae in pure culture synthesis
Mycorrhiza, 2000Co-Authors: J. L. Dahlstrom, Jane E Smith, N. S. WeberAbstract:Isolates from two species of Morchella were tested for ability to form mycorrhizae in pure culture synthesis with Arbutus Menziesii, Larix occidentalis, Pinus contorta, Pinus ponderosa, andPseudotsuga Menziesii. Ectomycorrhizal structures (mantle and Hartig net) formed with the four species of the Pinaceae but not with A. Menziesii. Results are compared to previous studies on morel mycorrhizae and discussed in an ecological context.
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Diversity and host specificity of ectomycorrhizal fungi retrieved from three adjacent forest sites by five host species
Botany, 1999Co-Authors: Hugues B. Massicotte, Randy Molina, Jane E Smith, Linda E. Tackaberry, Michael P. AmaranthusAbstract: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 hos...
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biology of the ectomycorrhizal genus rhizopogon iii influence of co cultured conifer species on mycorrhizal specificity with the arbutoid hosts arctostaphylos uva ursi and Arbutus Menziesii
New Phytologist, 1997Co-Authors: Randy Molina, Jane E Smith, Donaraye Mckay, L H MelvilleAbstract:Seedlings of Pseudotsuga Menziesii (Mirb.) Franco, Pinus ponderosa Dougl. ex Laws, Arbutus Menziesii Pursh., and cuttings of Arctostaphylos uva-ursi (L.) Spreng were grown in monoculture and in conifer-hardwood dual-culture combinations in the glasshouse and inoculated with spore slurries of six Rhizopogon species. The primary objectives were to assess and compare the pattern of host specificity between symbionts and to study the influence of co-cultured plants on ectomycorrhiza development. The Rhizopogon spp. ranged from genus-specific to multiple-host compatible. In monoculture, four Rhizopogon sp. (R. ellenae Smith, R. occidentalis Zeller & Dodge, R. smithii Hosford and R. subcaerulescens Smith) formed ectomycorrhizas with Pinus ponderosa, and two Rhizopogon sp. (R. parksii Smith and R. vinicolor Smith) formed ectomycorrhizas with Pseudotsuga Menziesii. None of the fungi tested developed ectomycorrhizas on Arbutus Menziesii or Arctostaphylos uva-ursi in monoculture. In dual culture, three of the four Rhizopogon species (R. ellenae, R. occidentalis and R. subcaerulescens) that formed ectomycorrhizas on Pinus ponderosa, formed some ectomycorrhizas on Arbutus Menziesii and Arctostaphylos uva-ursi. Rhizopogon parksii and R. vinicolor only formed ectomycorrhizas on Pseudotsuga Menziesii.
Donaraye Mckay - One of the best experts on this subject based on the ideXlab platform.
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biology of the ectomycorrhizal genus rhizopogon iii influence of co cultured conifer species on mycorrhizal specificity with the arbutoid hosts arctostaphylos uva ursi and Arbutus Menziesii
New Phytologist, 1997Co-Authors: Randy Molina, Jane E Smith, Donaraye Mckay, L H MelvilleAbstract:Seedlings of Pseudotsuga Menziesii (Mirb.) Franco, Pinus ponderosa Dougl. ex Laws, Arbutus Menziesii Pursh., and cuttings of Arctostaphylos uva-ursi (L.) Spreng were grown in monoculture and in conifer-hardwood dual-culture combinations in the glasshouse and inoculated with spore slurries of six Rhizopogon species. The primary objectives were to assess and compare the pattern of host specificity between symbionts and to study the influence of co-cultured plants on ectomycorrhiza development. The Rhizopogon spp. ranged from genus-specific to multiple-host compatible. In monoculture, four Rhizopogon sp. (R. ellenae Smith, R. occidentalis Zeller & Dodge, R. smithii Hosford and R. subcaerulescens Smith) formed ectomycorrhizas with Pinus ponderosa, and two Rhizopogon sp. (R. parksii Smith and R. vinicolor Smith) formed ectomycorrhizas with Pseudotsuga Menziesii. None of the fungi tested developed ectomycorrhizas on Arbutus Menziesii or Arctostaphylos uva-ursi in monoculture. In dual culture, three of the four Rhizopogon species (R. ellenae, R. occidentalis and R. subcaerulescens) that formed ectomycorrhizas on Pinus ponderosa, formed some ectomycorrhizas on Arbutus Menziesii and Arctostaphylos uva-ursi. Rhizopogon parksii and R. vinicolor only formed ectomycorrhizas on Pseudotsuga Menziesii.
Michael Newton - One of the best experts on this subject based on the ideXlab platform.
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Twenty-six-year response of ponderosa pine and Douglas-fir plantations to woody competitor density in treated stands of madrone and whiteleaf manzanita
Forest Ecology and Management, 2008Co-Authors: Michael Newton, Elizabeth C. ColeAbstract:Ponderosa pine (Pinus ponderosa Dougl.) grown in mixture with whiteleaf manzanita (Arctostaphylos viscida Parry) and Douglas-fir (Pseudotsuga Menziesii (Mirb.) Franco var. Menziesii) grown in mixture with Pacific madrone (Arbutus Menziesii Pursh) in southwestern Oregon showed an increase in growth with removal of competing woody cover. Both conifer species had roughly one-third the volume at plantation ages 26-27 when grown with uncontrolled competition compared to where woody competition was completely controlled at age 2. Intermediate levels of competitors usually led to intermediate levels of growth, but this was more evident with Douglas-fir than pine. When competition was reduced or removed, height/age relationships for Douglas-fir at plantation ages 23 and 27 reflected medium site quality rather than low quality as estimated from adjacent stands, indicating that these sites are potentially more productive than perceived with uncontrolled dense woody cover. These studies support the concept that competition management may allow some poor sites of ponderosa pine or Douglas-fir to be managed on the basis of a higher site potential.
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Roots growing in rock fissures: Their morphological adaptation
Plant and Soil, 1995Co-Authors: Maciej A. Zwieniecki, Michael NewtonAbstract:On sites with shallow soil in semi-arid climate conditions, whiteleaf manzanita ( Arctostaphyllos viscida ) and Pacific madrone ( Arbutus Menziesii ) utilize water from the bedrock. Roots of these plants occupy rock fissures as small as 100 μm. Although the root stele remains cylindrical in shape without visible mechanical stress, the cortex may become flat, creating “wing-like” structures on the sides of the stele. Fine particles of soil and rock that fill the space between root cortex and rock matrices create good contact for water flow.
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Varying densities of Pacific madrone in a young stand in Oregon alter soil water potential, plant moisture stress, and growth of Douglas fir.
Forest Ecology and Management, 1990Co-Authors: Robert J. Pabst, John C. Tappeiner, Michael NewtonAbstract:Abstract Soil water-potential and Douglas fir [Pseudotsuga Menziesii (Mirb.) Franco] moisture stress and growth were studied on a droughty, 2-ha site in southwest Oregon where Pacific madrone (Arbutus Menziesii Pursh) and associated shrub and herbaceous vegetation were thinned to represent the following range of conditions: high-density madrone (H), with associated shrubs and herbs controlled; medium-density madrone (M), shrubs and herbs controlled; low-density madrone (L), shrubs and herbs controlled; no madrone (N), shrubs and herbs controlled; and no madrone (U), shrubs and herbs predominate. Soil water-potential (Ψs) at a depth of 0–30 cm was consistently higher in treatment N than in all other treatments; in 1987 this difference was significant (P Predawn plant moisture stress ( pms ) of Douglas fir was significantly (P=0.0001) less in treatment N than in all other treatments. Seasonal moisture-stress relief ( smsr ) of Douglas fir was significantly related to madrone leaf area index (L) (r2=0.75, P=0.003), and was greatest in treatment N. Seasonal moisture-stress relief of madrone was also significantly correlated with L (r2=0.66, P=0.03). There were highly significant linear relationships between both predawn and midday pms and soil water-potential for Douglas fir (r2=0.76 and 0.75) and madrone (r2=0.69 and 0.79). Results clearly show that conditions for maximum Douglas-fir growth occurred in treatment N, in which all madrone and the associated vegetation were controlled. Average diameter growth of Douglas fir was greatest in treatment N, although not significantly different from that in treatment U, and least in treatment H. In 1987, Douglas-fir growth in diameter, stem basal-area, and stem volume was strongly related to smsr (r2=0.62–0.81) and madrone L (r2=0.66–0.87), and to a lesser extent, seasonal soil tension relief ( sstr ) (r2=0.51–0.62).
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Relationship of Pacific Madrone Sprout Growth to Productivity of Douglas-Fir Seedlings and Understory Vegetation
Western Journal of Applied Forestry, 1990Co-Authors: Thomas F. Hughes, John C. Tappeiner, Michael NewtonAbstract: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.
