Watershed-scale Vegetation Patterns in a Late-successional Forest Landscape in the Oregon Coast Range

Watershed-scale Vegetation Patterns in a Late-successional Forest Landscape in the Oregon Coast Range
Author: Michael C. Wimberly
Publisher:
Total Pages: 356
Release: 1999
Genre: Forest ecology
ISBN:

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.

Characteristics of Remnant Old Growth Forests in the Northern Coast Range of Oregon and Comparison to Surrounding Landscapes

Characteristics of Remnant Old Growth Forests in the Northern Coast Range of Oregon and Comparison to Surrounding Landscapes
Author: Andrew N. Gray
Publisher: DIANE Publishing
Total Pages: 52
Release: 2011-05
Genre: Nature
ISBN: 1437926126

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.

Forest and Stream Management in the Oregon Coast Range

Forest and Stream Management in the Oregon Coast Range
Author: Stephen D. Hobbs
Publisher:
Total Pages: 336
Release: 2002
Genre: Nature
ISBN:

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.

Natural Vegetation of Oregon and Washington

Natural Vegetation of Oregon and Washington
Author: Jerry F. Franklin
Publisher:
Total Pages: 426
Release: 1973
Genre: Botany
ISBN:

Major vegetational units of Oregon and Washington and their environmental relationships are described and illustrated. After an initial consideration of the vegetation components in the two States, major geographic areas and vegetation zones are detailed. Descriptions of each vegetation zone include composition and succession, as well as discussion of variations associated with environmental gradients. Three chapters treat the forested zones found in the two States. Major emphasis is on the distinctive mesic temperate forests found in western Washington and northwestern Oregon. The interior valley forests, shrub lands, and prairies found between the Coast and Cascade Ranges in western Oregon are treated in a single chapter as are subalpine and alpine mosaics of tree-dominated and meadow communities. Unusual habitats, such as areas of recent vulcanism, serpentines, and ocean strand, are individually described. Soils, geology, and climate are considered in broad outline in an early chapter and in greater detail within discussions of individual geographic areas and vegetation zones. Appendices are included for definition of the various soil types, scientific and common plant names, and a subject index. An extensive bibliography is included to direct the reader to other references.

Ecosystem Management

Ecosystem Management
Author: B. Narayan
Publisher: APH Publishing
Total Pages: 320
Release: 2000
Genre: Ecological disturbances
ISBN: 9788176482134

The Land-water Interface

The Land-water Interface
Author: Mayumi Takahashi
Publisher:
Total Pages: 170
Release: 2003
Genre: Riparian ecology
ISBN:

This study was conducted to describe variation of riparian vegetation in an Oregon Coast Range system according to geomorphic characteristics and in relation to streamflow. Specific objectives of this study were to: I) examine if the vegetation composition and structure of the riparian forest varied among channel-reach morphologies, 2) examine how the composition and structure of the riparian forest changed with distance from the stream, and 3) extract major underlying environmental gradients explaining riparian forest community from riparian vegetation data. A 30 m x 30 m sample site was randomly located on each side of upper Camp Creek in each of 19 reaches, and within each site three consecutive 30 m x 10 m belt-transects established perpendicular to the stream flow. Overstory and understory vegetation was sampled in each belt transect. Environmental variables sampled included slope, aspect, height above summer low flow, elevation above sea level. Non-metric Multidimensional Scaling and Indicator Species Analysis was used to describe characteristics of riparian plant communities. Distinct riparian vegetation patterns were observed in upper Camp Creek with increasing distance from stream. Both overstory and understory vegetation quickly changed with increasing distance from stream. Areas within ten meters from stream were characterized as mesic riparian environments while areas twenty meters away from stream were characterized as upland conifer forest environments. Vegetation composition was ordered along an inferred moisture gradient from streamside to hillslope, and distance from stream and height above summer low flow were almost equally correlated to the gradient. Tall shrubs including salmonberry, sword fern and vine maple are important component of riparian vegetation. Channel-reach morphology little differentiated riparian vegetation. A few species were significantly abundant in a specific reach of channel morphology. However, results of this study about relationships between channel-reach morphology and riparian vegetation were inconclusive.

Characteristics of Remnant Old-Growth Forests in the Northern Coast Range of Oregon and Comparison to Surrounding Landscapes

Characteristics of Remnant Old-Growth Forests in the Northern Coast Range of Oregon and Comparison to Surrounding Landscapes
Author: United States Department of Agriculture
Publisher: CreateSpace
Total Pages: 50
Release: 2015-02-14
Genre:
ISBN: 9781506119113

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.

Policy Patterns Across Riverscapes

Policy Patterns Across Riverscapes
Author: Brett A. Boisjolie
Publisher:
Total Pages: 120
Release: 2016
Genre: Buffer zones (Ecosystem management)
ISBN:

Land management policies are ideas about nature projected onto the landscape. Culminations of social, economic, and scientific influences, these policies create standards affecting the function of ecological systems. In the case of riparian lands in the Oregon Coast Range, policy requirements vary considerably across federal, state, and private land ownerships. Protective measures, such as the adoption of fixed buffer widths for maintaining vegetation, are intended to preserve natural processes important to instream habitat and water quality. However, the "policy landscape" of variable management standards can result in a fragmented approach to policy protection. This fragmentation complicates recovery efforts for threatened anadromous fish species such as coho salmon (Oncorhynchus kisutch), which require connectivity in suitable habitat segments throughout the river network. Taking a riverscape perspective, this study evaluates how aquatic protections vary across the river and its valley. To explore the patterns created from variable standard, the study first delineates categories of riparian management standards in the Oregon Coast Range. Using a geographic information system (GIS), these standards are mapped across the river networks of this region. The extent of each policy category is quantified in stream kilometers in order to evaluate policy efforts within and across the riverscapes of the Oregon Coast Range. A model of intrinsic potential for coho salmon habitat is used to identify the policy standards in stream reaches where flow, valley constraint, and channel gradient are appropriate for coho salmon habitat. A second model of the stream network (hydrography) is developed to evaluate how differences in stream delineation can influence policy patterns. Results indicate that riparian lands of the Oregon Coast Range are protected by variable standards for land management, including buffer widths that range from 0 to ~152m. In streams important to coho salmon, a lower proportion of the stream network was found to be protected by policy standards compared to the watershed and ESU scale. A lack of stream data central to policy application (fish use, stream flow duration, mean annual flow, water use) complicated our ability to attribute stream segments with specific land management requirements. The choice of hydrographic data was also found to influence the proportional extent of policies within riverscapes. This framework for assessing the spatial distribution of policies can provide insights for future studies of riverscape systems.