Structural Development of Late Successional Forests in the Central Oregon Coast Range PDF Download
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Author: Barbara A. Schrader
Publisher:
ISBN:
Category : Western hemlock
Languages : en
Pages : 350
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Book Description
Patterns of western hemlock regeneration were studied in relation to forest structural development and environment in the Oregon Coast Range. Density of western hemlock seedlings was examined across the climatic gradient from cool, moist coastal areas to the seasonally hot and dry Willamette Valley Margin. Seedling densities were most strongly related to stand-level variables including stand age, frequency and abundance of overstory western hemlock trees, abundance of coarse woody debris, decreasing shrub cover, and increasing overstory conifer cover. Significant regional climate and topographic variables included mean annual temperature, precipitation and elevation. Dispersal distances between western hemlock seedlings and potential parents were characterized by measuring distances between seedlings and potential parents. Cone production in western hemlock trees by size class was estimated in four late successional Coast Range stands. Dispersal distances were most commonly short - generally within 10 meters of the nearest potential parent tree. Cone production was related to diameter and crown position, with larger codominant and dominant trees producing more cones than smaller trees. Dynamics and age structure of western hemlock in late successional forests was described in terms of age and size distributions, rooting patterns, and growth rates of western hemlock seedlings, saplings, and trees across the climatic gradient and related to stand level factors in six late successional forests. Time between initial and subsequent western hemlock regeneration pulses varied between 40-70 years. These patterns were observed in all stands. Striking differences in substrate colonization patterns were observed between seedlings and trees and at climatic extremes. Seedlings were predominantly observed on decaying wood while trees were generally observed on forest floor substrates. An exception to this pattern occurred in near-coastal sites where western hemlock of all size classes were found almost entirely on decaying wood substrates. Growth rates across size classes were also calculated and related to regional and stand-level variables. Highest growth rates occurred in low elevation coastal sites, in stands containing the highest levels of coarse woody debris, and the highest level of canopy gaps. Seedling growth rates averaged 4 cm/year for seedlings, and between .2-.6 cm/year diameter growth for overstory saplings and trees.
Author: Barbara A. Schrader
Publisher:
ISBN:
Category : Western hemlock
Languages : en
Pages : 350
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Book Description
Patterns of western hemlock regeneration were studied in relation to forest structural development and environment in the Oregon Coast Range. Density of western hemlock seedlings was examined across the climatic gradient from cool, moist coastal areas to the seasonally hot and dry Willamette Valley Margin. Seedling densities were most strongly related to stand-level variables including stand age, frequency and abundance of overstory western hemlock trees, abundance of coarse woody debris, decreasing shrub cover, and increasing overstory conifer cover. Significant regional climate and topographic variables included mean annual temperature, precipitation and elevation. Dispersal distances between western hemlock seedlings and potential parents were characterized by measuring distances between seedlings and potential parents. Cone production in western hemlock trees by size class was estimated in four late successional Coast Range stands. Dispersal distances were most commonly short - generally within 10 meters of the nearest potential parent tree. Cone production was related to diameter and crown position, with larger codominant and dominant trees producing more cones than smaller trees. Dynamics and age structure of western hemlock in late successional forests was described in terms of age and size distributions, rooting patterns, and growth rates of western hemlock seedlings, saplings, and trees across the climatic gradient and related to stand level factors in six late successional forests. Time between initial and subsequent western hemlock regeneration pulses varied between 40-70 years. These patterns were observed in all stands. Striking differences in substrate colonization patterns were observed between seedlings and trees and at climatic extremes. Seedlings were predominantly observed on decaying wood while trees were generally observed on forest floor substrates. An exception to this pattern occurred in near-coastal sites where western hemlock of all size classes were found almost entirely on decaying wood substrates. Growth rates across size classes were also calculated and related to regional and stand-level variables. Highest growth rates occurred in low elevation coastal sites, in stands containing the highest levels of coarse woody debris, and the highest level of canopy gaps. Seedling growth rates averaged 4 cm/year for seedlings, and between .2-.6 cm/year diameter growth for overstory saplings and trees.
Author: Andrew N. Gray
Publisher: DIANE Publishing
ISBN: 1437926126
Category : Nature
Languages : en
Pages : 52
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Book Description
Old-growth forests provide unique habitat features and landscape functions compared to younger stands. The goals of many forest mgmt. plans in the Pacific NW include increasing the area of late-successional and old-growth forests. This study describes existing old-growth forests in the northern Oregon Coast Range that might serve as examples of desired future conditions and developmental pathways. Results suggest that although old-growth forests can develop along multiple pathways, stand composition and productivity constrain development such that expecting all late-successional stands to have the full complement of old-growth attributes may not be realistic. Illustrations. This is a print on demand report.
Author: Michael C. Wimberly
Publisher:
ISBN:
Category : Forest ecology
Languages : en
Pages : 356
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Book Description
Knowledge about vegetation patterns and ecological processes in unmanaged, late-successional watersheds is needed to provide a foundation for forest management strategies aimed at conserving native biodiversity. I examined influences of environmental variability and disturbance history on forest structure and composition in the Cummins Creek Wilderness, located on the central Oregon coast. Climatic and topographic variables explained the majority of hillslope community composition, while fire history explained most of the variability in hillslope forest structure. Forest structure and composition in riparian areas was related to a climatic gradient as well as position in the stream network. The abundance of two fire-sensitive species, Tsuga heterophylla (western hemlock) and Picea sitchensis (Sitka spruce), decreased with distance from old-growth patches, possibly reflecting a seed dispersal gradient that occurred following fires 80 to 140 years ago. I developed predictive maps of understory conifer patterns using remote sensing, aerial photographs, digital elevation models and stream maps. I predicted P. sitchensis regeneration based on distance from the coast and topography, and T. heterophylla regeneration based on crown size, percent hardwood composition, topography, and distance from old-growth patches. Although I found statistically significant relationships between understory patterns and GIS predictor variables, the models explained only low to moderate amounts of the overall variability. Landscape-scale simulations of T. heterophylla showed that population expansion through gap-phase recruitment was limited by short seed dispersal distances in closed-canopy forests, the requirement for canopy gap disturbances to facilitate overstory recruitment, and the lag between recruitment and reproduction. Although fine-scale habitat features can influence the amount of regeneration in a gap when seed sources are present, the fire regime may ultimately control the abundance of T. heterophylla at the landscape scale through dispersal limitations. Brief increases in fire frequency can cause a sustained decrease in the amount of T. heterophylla on the landscape once fire frequency is reduced below a threshold value. Our results emphasize the complexity and diversity of forest vegetation at the watershed scale. Environmental variability, disturbance history, and dispersal limitations have all played a role in creating the current landscape patterns in the Cummins Creek Wilderness.
Author: United States Department of Agriculture
Publisher: CreateSpace
ISBN: 9781506119113
Category :
Languages : en
Pages : 50
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Book Description
Old-growth forests provide unique habitat features and landscape functions compared to younger stands. The goals of many forest management plans in the Pacific Northwest include increasing the area of late-successional and old-growth forests. The goal of this study was to describe existing old-growth forests in the northern Oregon Coast Range that might serve as examples of desired future conditions and developmental pathways. In addition, the abundance of specific stand attributes associated with old-growth stands was estimated from regional inventory data. Most of the old-growth stands had experienced moderately severe disturbances during their development resulting in mid- and understory trees belonging to cohorts younger than those of overstory trees. Most of the stands had the full complement of old-growth attributes (large shade-intolerant trees, shadetolerant trees, snags, and down wood), although the dead wood attributes tended to be less abundant in drier stand types. Thresholds for at least four of the five old-growth attributes were met on 7 percent of the inventory plots on federal lands, but on only 0.4 percent of the inventory plots on nonfederal lands. Shade-intolerant trees in particular were low in abundance in mature stands of intermediate diameter class (10 to 30 in). Large-diameter class stands (>30 in) were more abundant near the coast than near the Willamette Valley margin. Results suggest that although old-growth forests can develop along multiple pathways, stand composition and productivity constrain development such that expecting all late-successional stands to have the full complement of old-growth attributes may not be realistic.
Author:
Publisher:
ISBN:
Category : Forests and forestry
Languages : en
Pages : 696
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Book Description
Author: Stephen D. Hobbs
Publisher:
ISBN:
Category : Nature
Languages : en
Pages : 336
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Book Description
This major volume presents a wealth of fundamental and applied research on managing Coast Range forest and stream ecosystems. Written primarily for managers and resource specialists, the book will also appeal to policymakers, resource scientists, forest landowners, the conservation community, and students interested in forestry, fisheries, and wildlife sciences.
Author: Nathan Jeremy Poage
Publisher:
ISBN:
Category : Forest ecology
Languages : en
Pages : 268
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Book Description
Riparian forests in the central Oregon Coast Range vary along a coniferous-deciduous compositional continuum. Variations in structure and composition affect water quality, fish and wildlife, biodiversity, timber, and aesthetics. A retrospective approach was taken in this study in order to understand and compare the structure, pattern, and history of an unmanaged, mature, deciduous-dominated riparian forest and an unmanaged, mature, coniferous-dominated riparian forest in the central Oregon Coast Range. Information on forest structure and pattern was acquired by mapping locations of all trees and snags (DBH 5cm) within a 2.0 ha and a 2.25 ha reference stand. The history of each stand was reconstructed through analyses of stand structure and composition, tree ages, spatial patterns of trees and snags, as well as detailed field observations. The structure and composition of the two forests is very different. Non-random patterns of trees and snags were observed at multiple scales. Although it is not possible to infer directly the process(es) responsible for observed patterns, point-pattern analysis is a useful tool to detect and describe intra- and interspecific patterns. Neither forest resulted from a single, stand-replacing fire. Instead, both sites were at least partially burned about 145 years ago, possibly in the same fire(s) which spread across an estimated 500,000 acres between the Siuslaw and Siletz Rivers in the mid-1800's (Morris 1934). There is good evidence to suggest that a second fire occurred at the coniferous-dominated site. One or two other fires may have occurred at the deciduous-dominated site. Evidence of wind, herbivory, flooding, pathogens, mass movement events, and non-stand replacing fire was observed at one or both of the sites. Seed source availability as affected by disturbance history may have played a role in forest development at both sites. The seed source availability of red alder relative to Douglas-fir may have increased with successive disturbance events at the deciduous-dominated, riparian forest. A local source of western hemlock seed may have been a key factor in the development of the coniferous-dominated, riparian forest.
Author:
Publisher:
ISBN:
Category : Biodiversity conservation
Languages : en
Pages : 150
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Book Description
Author: Jianguo Liu
Publisher: Cambridge University Press
ISBN: 9780521784337
Category : Nature
Languages : en
Pages : 520
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Book Description
The rapidly increasing global population has dramatically increased the demands for natural resources and has caused significant changes in quantity and quality of natural resources. To achieve sustainable resource management, it is essential to obtain insightful guidance from emerging disciplines such as landscape ecology. This text addresses the links between landscape ecology and natural resource management. These links are discussed in the context of various landscape types, a diverse set of resources and a wide range of management issues. A large number of landscape ecology concepts, principles and methods are introduced. Critical reviews of past management practices and a number of case studies are presented. This text provides many guidelines for managing natural resources from a landscape perspective and offers useful suggestions for landscape ecologists to carry out research relevant to natural resource management. In addition, it will be an ideal supplemental text for graduate and advanced undergraduate ecology courses.
Author: Constantine Gatsonis
Publisher: Springer
ISBN: 1461220785
Category : Mathematics
Languages : en
Pages : 384
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Book Description
This volume contains invited case studies with the accompanying discussion as well as contributed papers selected by a refereeing process of 6th Workshop on Case Studies in Bayesian Statistics was held at the Carnegie Mellon University in October, 2001.
