Download or read book Analysis of Riparian Vegetation Age Structure Among the Forest Land Owners of the Central Oregon Cascades written by Christopher S. Purnell and published by . This book was released on 1994 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Research Publications of the H J Andrews Experimental Forest Cascade Range Oregon written by D. L. Henshaw and published by . This book was released on 1998 with total page 100 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book General Technical Report PNW GTR written by and published by . This book was released on 1997 with total page 940 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Remote Sensing and Ecosystem Management written by Jerry D. Greer and published by DIANE Publishing. This book was released on 1998-04 with total page 388 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book An Analysis of Montane Forest Vegetation on the East Flank of the Central Oregon Cascades written by Neil E. West and published by . This book was released on 1964 with total page 544 pages. Available in PDF, EPUB and Kindle. Book excerpt: Montane forest vegetation as it occurs on the east flank of the central Oregon Cascades has provided excellent conditions for a "natural experiment" in the use of various methodologies in studying vegetational distribution. This "experiment" has reflected on some theory and practice for the discipline of plant synecology. Detailed descriptions, analysis, and interpretation of the data also document present conditions in relation to the past and allow prognostication of future changes, which in turn may be of silvicultural importance for a portion of this forest type found extensively on the east flank of the Sierra Nevada-Cascades cordillera. A major objective of this study was to determine the relative merits and deficiencies of attempting to transpose to this vegetation the methods of analyzing vegetation based on the individualistic or continuum philosophy of phytosociology that has developed and been practiced principally in the north-central United States. These attempts have been contrasted to strengths and short-comings of poly-climax theory, the most widely used basis of vegetational classification in the Pacific Northwest, in relation to the analysis of this and other vegetation types. The influences on and of these varying interpretations have been outlined and presented in tabular form. The study area is nearly ideal for posing these questions because edaphic and topographic factor complexes remain surprisingly uniform. The vegetation is superimposed in apparent primary response to the condensed gradient of total precipitation due to the orographic "rain shadow" effect from the Cascades intervening in this region of prevailing westerly winds. The stability of the vegetation concomitant with this nearly ideal set of "naturally controlled" physical conditions, minimized variations in successional status, except that due to fire exclusion. This latter variation, however, paralleled the complex gradient studied, a happenstance which allowed silviculturally important interpretations to be made. Stable vegetation occurring in general contiguity allowed stands to be sampled systematically, leaving little doubt concerning the validity of interpolation between stands and the areal representation of the samples. Another main objective of the study was to obtain and analyze data to substantiate the hypothesized influence of light periodic ground fires in initiating and maintaining the characteristic mosaic of size-age class distribution of ponderosa pine. The data also yielded a quantitative indication of the shift in species composition and dominance that is in largest measure due to the continued exclusion of fire by man for approximately the past 50 years. From these data the future appearance of the forest can be surmised, and silvicultural manipulations can be suggested that are best in harmony with the ecology of these forests. The circumstances that provided this "natural experiment" have allowed the author to demonstrate certain limitations to direct transposition of methods widely used in other areas of the United States, or even the Pacific Northwest, when description and analysis in closest feasible parallel to the nature of the patterns of vegetational distribution found in this area are attempted. This finding catalyzed the development of a method incorporating cluster analysis of matrices of relative parameter-weighted coefficients of association into a means of making very objective synecological delimitations. The dendrograms derived from this analysis allow a "sliding scale" of stratification to be made in this vegetation of most realistically intermediate, yet of more continuously variable than unit-association nature.
Download or read book The Land water Interface written by Mayumi Takahashi and published by . This book was released on 2003 with total page 170 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book A Characterization of Unmanaged Riparian Overstories in the Central Oregon Coast Range written by Tara R. Nierenberg and published by . This book was released on 1996 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: Riparian areas that can be used as reference sites on which to base goals of vegetation restoration have not been documented in the Oregon Coast Range. I examined the composition and distribution of unmanaged riparian overstories in the central Oregon Coast Range along nine streams which have experienced minimal disturbance from Native Americans and no detectable disturbance since Euro- American settlement. I systematically located transects along nine streams, alternating sides of the streams. Each transect ran perpendicular to the stream and was subjectively divided into different vegetative and/or topographic units called landscape units (LU's). Rectangular plots were placed in each LU for characterization. LU l's were units that were closest to the stream, and LU2's were farther from the stream. Red alder was the most frequently found tree species on both terraces and slopes, and on all LU1 's. On LU2 terraces, alder was also the most frequently found species, but on LU2 slopes, Douglas-fir had the highest frequency. Red alder, Sitka spruce, and bigleaf maple were most commonly found occupying terrace sites, although bigleaf maple might be best adapted to conditions on terraces towards the base of slopes. Conversely, western hemlock and Douglas-fir were most commonly found occupying slope sites. Western redcedar was infrequently found, likely due to seed source limitations. Age distributions and tree frequencies indicate that near-stream communities (LUI 's) and terraces experience both intense and minor disturbances, and they experience both types of disturbances more frequently than communities farther from the stream (LU2's) or on slopes. According to fire records and reconnaissance, all streams appear to have been burned about 145 years ago. When equating a shade-intolerant tree age that was younger than this last catastrophic fire date with a disturbance, calculations of disturbance frequency using four different approaches indicate that between 2.6 and 4.5 disturbances per km per century large enough to regenerate trees occurred since the last stand-resetting fire along the nine creeks sampled. Fifty-two percent of near-stream communities (LU1's) and 23% of communities farther from the stream (LU2's) contained no trees. This could be due to small plot size and/or high shrub competition. The No Tree overstory type was most similar in topographic conditions to the Pure Hardwood overstory type, suggesting that red alder and/or bigleaf maple might have previously occupied the No Tree sites and have since died leaving no or little evidence. It appears that a large-scale, intense disturbance such as fire is needed to allow the recruitment of trees into the shrub-dominated, No Tree areas, especially shade-intolerant trees such as Douglas-fir. Any single definition of natural riparian vegetation is nearly impossible to construct, mainly because most ecosystems are composed of vegetation mosaics that are always changing in time and space. This change is associated with environmental variability, disturbance, and inter- and intra-specific competition. Also, differences in exogenous environmental conditions between pre-settlement times (circa 1850) and today, suggest that historic vegetation, ecological conditions, and resulting successional pathways might not mirror the vegetation, ecological conditions, and successional pathways of currently unmanaged riparian areas. Instead, results from this study, revealing the existence of mixtures of hardwoods, conifers, and no-tree areas over lengths of a stream, should be perceived as just one of many possibilities for a riparian overstory reference model.
Download or read book Comparison of Stand Development of a Deciduous dominated Riparian Forest and a Coniferous dominated Riparian Forest in the Oregon Coast Range written by Nathan Jeremy Poage and published by . This book was released on 1994 with total page 268 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.
Download or read book Riparian Areas written by National Research Council and published by National Academies Press. This book was released on 2002-10-10 with total page 449 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Clean Water Act (CWA) requires that wetlands be protected from degradation because of their important ecological functions including maintenance of high water quality and provision of fish and wildlife habitat. However, this protection generally does not encompass riparian areasâ€"the lands bordering rivers and lakesâ€"even though they often provide the same functions as wetlands. Growing recognition of the similarities in wetland and riparian area functioning and the differences in their legal protection led the NRC in 1999 to undertake a study of riparian areas, which has culminated in Riparian Areas: Functioning and Strategies for Management. The report is intended to heighten awareness of riparian areas commensurate with their ecological and societal values. The primary conclusion is that, because riparian areas perform a disproportionate number of biological and physical functions on a unit area basis, restoration of riparian functions along America's waterbodies should be a national goal.
Download or read book Riparian Vegetation in Oregon s Western Cascade Mountains written by Alsie Gilbert Campbell and published by . This book was released on 1979 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt: Sixteen understory plant communities in the riparian zones of small streams are identified and described. They range from pioneer communities on gravel and rock to well-developed shrub communities on flood plains and terraces. Several other vegetation types are discussed. Distribution of communities within the riparian zone is also discussed. A survey of nine small streams shows the Acer circinatum community to have the widest distribution and highest cover, but the Rubus spectabilis/Ribes bracteosum community is somewhat more common in the active zone. Biomass estimates are made for riparian vegetation along three stream segments. Total foliar production for 1976 is calculated for all vegetation, for communities, and for individual species. The percentage of each type of foliage which may reach the stream directly, indirectly, or not at all is estimated. Abscission and fall senescence for thirteen species was monitored. Leafy and herbaceous detrital input is timed. Rates of leaf fall and decadence are related to environmental factors.
Download or read book General Technical Report INT written by and published by . This book was released on 1992 with total page 738 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Forested Plant Associations of the Oregon East Cascades written by Michael Simpson and published by . This book was released on 2007 with total page 612 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Selected Water Resources Abstracts written by and published by . This book was released on 1990 with total page 710 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Riparian Areas written by National Research Council and published by National Academies Press. This book was released on 2002-09-10 with total page 448 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Clean Water Act (CWA) requires that wetlands be protected from degradation because of their important ecological functions including maintenance of high water quality and provision of fish and wildlife habitat. However, this protection generally does not encompass riparian areasâ€"the lands bordering rivers and lakesâ€"even though they often provide the same functions as wetlands. Growing recognition of the similarities in wetland and riparian area functioning and the differences in their legal protection led the NRC in 1999 to undertake a study of riparian areas, which has culminated in Riparian Areas: Functioning and Strategies for Management. The report is intended to heighten awareness of riparian areas commensurate with their ecological and societal values. The primary conclusion is that, because riparian areas perform a disproportionate number of biological and physical functions on a unit area basis, restoration of riparian functions along America's waterbodies should be a national goal.
Download or read book Fish Wildlife Annual Project Summary written by United States. Bonneville Power Administration. Division of Fish and Wildlife and published by . This book was released on with total page 114 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book A Year in Review for the Pacific Northwest Research Station written by Pacific Northwest Research Station (Portland, Or.) and published by . This book was released on 1998 with total page 132 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Age Structure Developmental Pathways and Fire Regime Characterization of Douglas fir western Hemlock Forests in the Central Western Cascades of Oregon written by Alan J. Tepley and published by . This book was released on 2011 with total page 556 pages. Available in PDF, EPUB and Kindle. Book excerpt: Descriptions of the fire regime in the Douglas-fir/western hemlock region of the Pacific Northwest traditionally have emphasized infrequent, predominantly stand-replacement fires and an associated linear pathway of stand development, where all stands proceed along a common pathway until reset by the next fire. Although such a description may apply in wetter parts of the region, recent fire-history research suggests drier parts of the region support a mixed-severity regime, where most fires have substantial representation of all severity classes and most stands experience at least one non-stand-replacing fire between stand-replacement events. This study combines field and modeling approaches to better understand the complex fire regime in the central western Cascades of Oregon. Stand-structure data and ages of more than 3,000 trees were collected at 124 stands throughout two study areas with physiography representative of western and eastern portions of the western Cascade Range. Major objectives were to (1) develop a conceptual model of fire-mediated pathways of stand development, (2) determine the strengths of influences of topography on spatial variation in the fire regime, (3) provide a stronger understanding of modeling approaches commonly used to gain insight into historical landscape structure, and (4) develop methods to predict trajectories of change in landscape age structure under a non-stationary fire regime. In the study area, non-stand-replacing fire interspersed with infrequent, stand-replacement events led to a variety of even-aged and multi-cohort stands. The majority of stands (75%) had two or more age cohorts, where post-fire cohorts were dominated either by shade-intolerant species or shade-tolerant species, depending largely on fire severity. Age structure, used as a proxy for the cumulative effects of fire on stand development, showed a moderately strong relationship to topography overall, but relationships were strongest at both extremes of a continuum of the influences of fire frequency and severity on stand development and relatively weak in the middle. High topographic relief in the eastern part of the western Cascades may amplify variation in microclimate and fuel moisture, leading to a finer-scale spatial variation in fire spread and behavior, and thus a broader range of stand age structures and stronger fidelity of age structure to slope position and terrain shape in the deeply dissected terrain of the eastern part of the western Cascades than in the gentler terrain of the western part. In the modeling component of my research, I was able to use analytical procedures to reproduce much of the output provided by a stochastic, spatial simulation model previously applied to evaluate historical landscape structure of the Oregon Coast Range. The analytical approximation provides an explicit representation of the effects of input parameters and interactions among them. The increased transparency of model function given by such an analysis may facilitate communication of model output and uncertainty among ecologists and forest managers. Analytical modeling approaches were expanded to characterize trajectories of change in forest age structure in response to changes in the fire regime. Following a change in fire frequency, the proportion of the landscape covered by stands of a given age class is expected to change along a non-monotonic trajectory rather than transition directly to its equilibrium abundance under the new regime. Under some scenarios of change in fire frequency, the time for the expected age distribution of a landscape to converge to the equilibrium distribution of the new regime can be determined based only on the magnitude of change in fire frequency, regardless of the initial value or the direction of change. The theoretical modeling exercises provide insight into historical trends in the study area. Compiled across all sample sites, the age distribution of Douglas-fir trees was strongly bimodal. Peaks of establishment dates in the 16th and 19th centuries were synchronous between the two study areas, and each peak of Douglas-fir establishment coincides with one of the two periods of region-wide extensive fire identified in a previous synthesis of fire-history studies. The modeling exercises support the development of such a bimodal age distribution in response to centennial-scale changes in fire frequency, and they illustrate how the relative abundance of different stand-structure types may have varied over the last several centuries.
