Download or read book Structure and Development of Old growth Douglas fir in Central Western Oregon written by Nathan Jeremy Poage and published by . This book was released on 2000 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt: The tree species and size structure of 9l old-growth forests dominated by Douglas-fir in central western Oregon was characterized using complete inventories of all trees larger than 20cm dbh over a mean area of 17.1ha at each site. Douglas-fir accounted for over 75% of the total average basal area (39.1 of 49.2 m2/ha) at each site. Conventional and multivariate analysis indicated that the non-Douglas-fir component accounted for most of the structural variation between sites. Multivariate analysis characterized six groups based on the similarities and differences among sites in basal area of small (20-50cm dbh), medium (50-100cm dbh), and large (> 100cm dbh) western hemlock, western red cedar, incense-cedar, grand fir, red alder, and bigleaf maple. The hypothesis that large-diameter, old-growth Douglas-fir in central western Oregon developed at low stand densities was supported by patterns of long-term diameter and basal area growth of trees, wide mean within-site age ranges (95% CI for mean = 134-214yr), and stem and crown characteristics. The diameters of the old-growth trees at ages 100 to 300yr were strongly, positively, and linearly related to their diameters at age 5Oyr and, more importantly, to their basal area growth rates as young, 50 year-old trees. Rapid and sustained growth by age 50yr was strongly correlated with large diameters at older ages, particularly at ages 100-200yr. Average periodic basal area increments (PAI[subscript]BA) of all trees increased for the first 30-4Oyr and then plateaued, remaining relatively high and constant from age 50 to 300yr. Over a third of the trees> 300 years old had not reached culmination of mean annual basal area increment (MAI[subscript]BA) by age 300yr. Low heights to live and dead meristematic branches suggest that many of the old-growth trees grew at low stand densities. Live branches occurred on over 50% of the bole, on average. Average height to diameter ratios of the old-growth trees were below 50 (unitless), indicating high mechanical stability. Compared to young-growth trees in high-density stands, young-growth trees in low-density stands have crowns and height-to-diameter ratios more similar to old-growth trees.

Download or read book Comparing Structure and Development of Douglas fir Old growth Plantations and Young Natural Forests in Western Oregon written by Christopher D. Dowling and published by . This book was released on 2003 with total page 258 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ages, diameter growth, density, tree size, and species were studied in old-growth, plantation, and young natural Douglas-fir stands in three areas in western Oregon: the western and eastern Coast Range and the western Cascades. The purpose was to compare the development of these three stand types and to determine whether plantations and young natural stands would develop old-growth structures and characteristics. The Douglas-fir age ranges in plantations (8 to 15 yr) were much narrower and than the ranges of tree ages found in the young natural (21 to 102 yr) and in the old-growth stands (300 to 354 yr). This wide range of tree ages, along with diameter growth rates and tree and stand structural characteristics, supported the hypothesis that old-growth developed at low initial stand densities. These low initial stand densities, probably the result of prolonged stand establishment, likely enabled height and crown size advantages among old and younger trees. Dominant and large codominant trees maintained live crown ratios and sustained diameter growth resulting in large stable trees indicated by low height-to-diameter ratios. The mean diameters of the dominant trees in the old-growth and the dominant trees in the young natural stands were not significantly different at age 40 and 100, indicating the young natural stands appear to be growing at the same rates as the old-growth in its first 100 years. The mean dominant diameters in the plantations and old-growth at age 40 and 100 were significantly different, indicating the plantations are growing and developing differently than young natural and old-growth forests. Plantations had grown rapidly for the first 20 to 30 years, and computer simulation indicated that a significant rapid decline in radial growth would occur between ages 30 and 55. Simulations also indicate that during this period, the mean diameters of the dominant plantation trees would fall below those of the old-growth in two of the three stands by age 85. Pre-commercial thinning 20 to 25 years ago in the plantations has helped sustain high early growth rates for a longer period of time than would have occurred if thinning had not been performed. Additional thinning in the future is likely needed to maintain rapid current rates. When simulated to age 250 both the young natural stands and the plantations maintained higher densities of smaller diameter trees than the old-growth stands. This simulation result indicates the possible inability of these stands to self-thin to the densities found in old-growth stands without some sort of density-reducing disturbance. The broad range of tree ages in the old-growth stands suggests that stand disturbances are a normal part of old-growth development on these sites. Five different plantation thinning options were also simulated to age 250, including additional options with thinning of understory trees and ingrowth. The projections indicate that when the plantations are left unthinned they would generally develop trees with small live crowns and mean diameters but still produce stable dominant overstory trees (low H:D ratios). Shade tolerant understory trees and ingrowth, such as western hemlock, are a key part of old-growth development. These trees may reduce the rate of growth and alter crown structure of the overstory trees over extended periods of time (200+ years). Additional thinning, possibly in multiple entries, in both the overstory and understory may be necessary for dense plantations to develop the tree size heterogeneity found in local old-growth forests. I also demonstrated a methodology to determine site-specific management targets or goals for creating old-growth structure from plantations. This was performed using past and current forest structure and composition information within a local landscape scale of 500 to 1000 acres, typical of the public land checkerboard ownership pattern. Stand types making up the historical landscape are identified and described retrospectively using historical and current aerial photographs and digital orthophotos, cruise records, previous studies, and sample plots of standing and harvested forests. The degree of detail provided through this methodology will likely help forest managers to define complex late-successional characteristics of stands and landscapes. My results indicate that stand and project area-specific definitions of old-growth and clearly defined goals for young stand management will facilitate development of old forest characteristics.

Download or read book The Structure of Natural Douglas fir Forests in Western Washington and Western Oregon written by L. C. Kuiper and published by . This book was released on 1988 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Establishment Histories and Structural Development of Mature and Early Old growth Douglas fir Forests of Western Washington and Oregon written by James A. Freund and published by . This book was released on 2013 with total page 125 pages. Available in PDF, EPUB and Kindle. Book excerpt: Regeneration of tree populations following stand-replacing wildfires is an important process in the multi-century development of Douglas-fir- western hemlock forests. Temporal patterns of tree establishment in naturally regenerated, mid-aged (100 to 350 years) Douglas-fir-dominated forests have received little study in comparison with the abundance of research on regeneration in older Douglas-fir stands (>400 years of age). Increment cores were obtained from 1455 trees in 18 mature and early old-growth forests in western Washington and northwestern Oregon USA in order to determine temporal patterns of natural Douglas-fir regeneration following stand-replacing wildfire. Continuous regeneration of Douglas-fir for many decades following initiating fire was evident in all of the stands. The establishment period averaged 60 (range 32 to 99) years. The pattern observed contrasts both with the view of rapid (one- to two-decade) regeneration of Douglas-fir portrayed in early forestry literature and with reports of establishment periods exceeding 100 years in older (>400 year) Douglas-fir- western hemlock stands. Current intensive production forestry practices directed toward rapid and uniform stand closure following logging have no precedent in the historic natural patterns of Douglas-fir regeneration documented in this study. Conversely, results of this study provide evidence that early seral ecosystems persisted for several decades following wildfires. Patterns of structural development in mid-successional Douglas-fir dominated forests - a period in which forest structures evolve from the relatively simple conditions found in young forests to the complex old forests - is poorly understood. Stand structure and composition was analyzed in nine early old-growth (200 to 350 year old) Douglas-fir-dominated stands in western Washington and Oregon, all of which originated following a single stand-replacement wildfire. Structure and composition of live tree populations (density, diameters, and heights) as well as dead tree structures (snags and logs) were quantified and compared with conditions in previously reported studies of older (400-600-year old) forests. Stand-level attributes were analyzed using descriptive statistics, nonlinear regression, principal components analysis, and two old-growth indices. Variability among stands in specific structural features was large but consistent with the current conceptual model of Douglas-fir forest development. Diameter distributions generally exhibited a reverse-J shape, a characteristic of >450-year-old forests. Douglas-fir populated the tallest height classes and shade-tolerant species (e.g., western hemlock and Pacific silver fir) were present in lower (co-dominant and intermediate) canopy positions. Coarse woody debris was abundant in early old-growth stands in the form of both snags (42-140 m3ha[superscript -1]) and logs (172-584 m3 ha[superscript -1]). Scores for early old-growth stands calculated using existing old-growth structural indices were comparable to those in older (400 to 600year old) forests. The structural conditions and variability in these early old-growth forests are useful guides for managers seeking to accelerate development of complex structures in young Douglas-fir forests.

Download or read book Variability in Older Forest Structure in Western Oregon written by Nathan Jeremy Poage and published by . This book was released on 2002 with total page 230 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Managing for Biodiversity in Young Douglas fir Forests of Western Oregon written by and published by . This book was released on 2002 with total page 92 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Characteristics of Remnant Old Growth Forests in the Northern Coast Range of Oregon and Comparison to Surrounding Landscapes written by Andrew N. Gray and published by DIANE Publishing. This book was released on 2011-05 with total page 52 pages. Available in PDF, EPUB and Kindle. Book excerpt: 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.

Download or read book Revision of the Resource Management Plans of the Western Oregon Bureau of Land Management Districts written by and published by . This book was released on 2008 with total page 572 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vegetation Response Following Thinning in Young Douglas fir Forests of Western Oregon written by Liane R. Beggs and published by . This book was released on 2004 with total page 190 pages. Available in PDF, EPUB and Kindle. Book excerpt: Across western Oregon, Washington, and British Columbia, forest management practices over the past century reduced the amount of late-successional forest while simultaneously increasing the amount of young (less than 80 years old), managed Douglas-fir (Pseudotsuga menziesii) dominated forests. Recently, concerns over loss of late-successional habitat pushed management objectives on public lands away from timber production and toward maintenance and restoration of late-successional habitat. In accordance with these new objectives, The Young Stand Thinning and Diversity Study (YSTDS) was developed to test if thinning could accelerate development of latesuccessional habitat in young managed Douglas-fir forests. Though the YSTDS examines several components of forest ecosystems, the goal of this study was to investigate short-term (5-7 years post-treatment) responses of vegetation to thinning treatments and to evaluate this response in relation to long-term objectives of late-successional development. The study is located on the western slope of the central Oregon Cascades. It consists of four replications of four thinning treatments (treatment areas average 30 ha each) in 30-50 year old second-growth Douglas-fir forest stands. Treatments include a control, heavy thin, light thin, and light thin with gaps. Unlike traditional thinning, the thinning treatments in this study sought to maintain and enhance overstory structural diversity by: (1) retaining species other than Douglas-fir, (2) simulating low densities that characterized development of some old-growth stands, and (3) adding canopy gaps to enhance spatial diversity. Following treatment completion, first, third, and fifth-year vegetation responses were measured Results for overstory vegetation indicate that heavy thinning may accelerate development of large trees, one important component of old-growth structure. This was evident by faster growth of the largest trees in the heavy thin than in the control. A heavy thin may also permit more time for understory development than a lighter thin because canopies of heavy thinned stands remained open longer than canopies of light thinned stands. Variation in overstory cover, which may promote heterogeneous understory development, was higher in the treatment that included canopy gaps than in other treatments including the control. Although accelerated development of a multi-layered canopy was not evident in any treatment, retention of non-dominant tree species prevented simplification of vertical canopy structure by retaining layers that are typically removed by a low thinning prescription. In addition, mortality of non-dominant species was not greater in thinned treatments than in the control. In the understory, results suggest that thinning can increase abundance of some vegetative layers without encouraging homogenization of the understory by clonal shrubs or exotic species. The thinnings resulted in initial declines of bryophytes, tall shrubs, and low shrubs followed by subsequent recovery and growth. While herbs displayed little initial response, a release of early-seral species was evident by 5-7 years post-treatment. Initial changes following thinning were likely due to harvesting damage and/or alteration of microclimate while subsequent changes were probably also related to increased resource availability. It is expected that eventually similarities and differences in overstory structure among thinned treatments will be reflected in the understory. For example, variation in canopy cover created by the addition of canopy gaps was already reflected in the understory, as plant assemblages differed across the gradient from gaps to the thinned forest matrix. Hence, although understory vegetation was similar among heavy and light thins in the short-term, early closure of the canopy following a light thin could preclude continuation of late-seral understory development. Finally, the effect of canopy gaps on the understory was more apparent at a within-stand scale than at a stand scale. Had the within-stand scale been ignored, relevant information regarding understory response would have been overlooked. This indicates that spatial scale should be considered when assessing ecological patterns. In conclusion, it is acknowledged that there are drawbacks to thinning (e.g., certain species decline following thinning) It is also acknowledged that the short-term nature of the data permits only speculation regarding long-term succession. While these limitations are recognized, current trends indicate that a moderate to heavy thinning in combination with gap formation can hasten development of late-successional features in thinned stands relative to unthinned stands. Thus, thinning similar to that used in this study can be one useful tool in the management of young Douglas-fir forests.

Download or read book Restoring the Pacific Northwest written by Dean Apostol and published by Island Press. This book was released on 2012-09-26 with total page 505 pages. Available in PDF, EPUB and Kindle. Book excerpt: The Pacific Northwest is a global ecological "hotspot" because of its relatively healthy native ecosystems, a high degree of biodiversity, and the number and scope of restoration initiatives that have been undertaken there. Restoring the Pacific Northwest gathers and presents the best examples of state-of-the-art restoration techniques and projects. It is an encyclopedic overview that will be an invaluable reference not just for restorationists and students working in the Pacific Northwest, but for practitioners across North America and around the world.

Download or read book Old Growth in a New World written by Thomas A. Spies and published by Island Press. This book was released on 2012-09-26 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: Old-growth forests represent a lofty ideal as much as an ecosystem—an icon of unspoiled nature, ecological stability, and pristine habitat. These iconic notions have actively altered the way society relates to old-growth forests, catalyzing major changes in policy and management. But how appropriate are those changes and how well do they really serve in reaching conservation goals? Old Growth in a New World untangles the complexities of the old growth concept and the parallel complexity of old-growth policy and management. It brings together more than two dozen contributors—ecologists, economists, sociologists, managers, historians, silviculturists, environmentalists, timber producers, and philosophers—to offer a broad suite of perspectives on changes that have occurred in the valuing and management of old-growth forests in the Pacific Northwest over the past thirty years. The book • introduces the issues and history of old-growth values and conservation in the Pacific Northwest; • explores old growth through the ideas of leading ecologists and social scientists; • addresses the implications for the future management of old-growth forests and considers how evolving science and social knowledge might be used to increase conservation effectiveness. By confronting the complexity of the old-growth concept and associated policy and management challenges, Old Growth in a New World encourages productive discussion on the future of old growth in the Pacific Northwest and offers options for more effective approaches to conserving forest biodiversity.

Download or read book Upper Siuslaw Late successional Reserve Restoration Plan Lane and Douglas Counties written by and published by . This book was released on 2004 with total page 312 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Managed Forest Reserves written by John Tappeiner and published by . This book was released on 2005 with total page 4 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spatial and Temporal Patterns of super old Douglas fir Trees of the Central Western Cascades Oregon written by Sheryl K. Giglia and published by . This book was released on 2004 with total page 168 pages. Available in PDF, EPUB and Kindle. Book excerpt: Old-growth in the Pacific Northwest is generally defined as trees that are more than 200 years old. A great deal of analysis and discussion about old-growth forests in western Oregon, however, has focused on the relatively widespread 400 to 500 year age class of primarily Douglas-fir (Pseudotsuga menziesii) trees. The existence of older trees, with establishment dates prior to 1450, though rare, is documented in treering based fire history studies conducted in the central western Cascades of Oregon. These trees, referred to in this study as "super-old growth," embody significant information about forest and climate history extending nearly a millennium into the past. The primary objectives of this study were to assay where and why super-old trees persists on the landscape, and to develop a predictive model for their occurrence. I synthesized spatial and temporal data related to super-old trees from previous treering based fire history studies conducted in the central western Cascades of Oregon. I then created a composite, geographically referenced database, which was used to analyze the synthesized data. Super-old Douglas-fir trees were found at 12% of 874 sample sites, mostly on north-facing aspects and on gentle slope gradients. Even-aged stands of super-old trees were more likely to exist in areas that are prone to long fire intervals and highseverity fires. Single, remnant super-old trees were more likely to exist in areas that are prone to more frequent, lower-severity fires. This study identified landscape positions that provide a refuge where Douglasfir trees can attain maximum longevity. This information may be useful in determining optimal locations for late-successional reserves, as directed by the Northwest Forest Plan. Over 350 hectares of unsampled terrain within the study area were identified where more super-old trees could likely be found. Efforts to locate more super-old trees using these data could facilitate future paleoclimate research and other tree-ring based studies.

Download or read book Structure of Mature Douglas fir Stands in a Western Oregon Watershed and Implications for Interpretation of Disturbance History and Succession written by Mark Warren Klopsch and published by . This book was released on 1985 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The structure of a mature Douglas-fir (Pseudotsuga menziesii) forest in a watershed in the western Cascades of Oregon was examined. Two age classes were detected in the stand, the oldest originating about 1855 after an extensive fire and the younger following a second fire about 1895 Although the trees in the older age class had statistically greater diameters and heights, only open grown individuals mixed with the younger age class could be readily distinguished B cause reburns at young ages are common and may not leave firescars, great care is be required to distinguish between slow regeneration and patchy reburns The early stand history varied greatly between the two age classes More than 70% of the trees in the younger portion of the stand were established within a 15 year period while comparable establishment in the older areas required over 35 years The broad range of ages in older age class, combined with significantly lower stocking density and mortality, resulted in a nearly flat diameter distribution compared with a bell-shaped distribution for the younger age class. The stand is heavily dominated by Douglas-fir which accounts for about 90% of the trees in the younger age class and 77% of the trees in the older portions of the stand. The older portion of the drainage has significantly more western hemlock (Tsuga heterophylla) and western dogwood (Cornus nuttalili). The younger portion of the drainage contains more early successional hardwoods including the remnants of a considerable population of bitter cherry (Prunus emarginata) Currently, almost no western redcedar (Thuja plicata) is found in the drainage although old redcedar logs or snags are still present on one quarter of the plots. The abundance of western hemlock and redcedar is much less than similar aged stands in the nearby H.J Andrews Experimental Forest The slow regeneration of the site following the first fire probably reflects a shortage of seed due to a hot burn and dispersal distances four to ten times greater than those reported by Issac (1943) The low abundance of western hemlock and virtual elimination of redcedar are attributed to even greater dispersal distances, low mobility of redcedar seed, and harsh establishment conditions The rapid regeneration following the second fire suggests efficient seed dispersal or storage with young trees and the potential importance of the understory exclusion phase of stand development on regeneration.

Download or read book Fire History Fire Regimes and Development of Forest Structure in the Central Western Oregon Cascades written by Peter J. Weisberg and published by . This book was released on 1999 with total page 512 pages. Available in PDF, EPUB and Kindle. Book excerpt: Fire history and fire regimes were reconstructed for a 450 km2 area in the central western Oregon Cascades, using tree-ring analysis of fire scars and tree origin years at 137 sampled clearcuts. I described temporal patterns of fire frequency, severity, and size, and interpreted topographic influences on fire frequency and severity. I then evaluated the influences of fire history and topography on the development of forest structure. Ninety-four fire episodes were reconstructed for the 521-year period from 1475 to 1996. The average mean fire interval, Weibull median probability interval, and maximum fire interval of 4-ha sites were 97 years, 73 years, and 179 years, respectively. Fire regime has changed over time as a result of climate change, changing anthropogenic influences, and patterns of fuel accumulation related to stand development. Fire frequency and severity patterns were weakly but significantly associated with spatial variation in hillslope position, slope aspect, slope steepness, and elevation. Fire frequency was lower for higher elevations, lower slope positions, and more mesic slope aspects. Fire severity was lower for higher elevations, lower slope positions, more north-facing slopes, and more gradual slopes. Three fire regime classes were defined and mapped. Forest stand structures were strongly associated with stand age, fire history and topography. The number of years since the last high-severity fire was an important predictor for nearly all measured aspects of stand structure. Low-severity fires were important for creating variability in tree diameter sizes, reducing tree density and allowing more rapid diameter growth, and creating stand structures with many large snags and few overstory shade-tolerant trees. However, stands of the same age, and of the same general fire history, often had different structures. Much of this variation was explained by differences in topography. The strongly positive influence of wet aspects and high elevations on the relative dominance of shade-tolerant tree species has been important for shaping the structure of forest stands. Development of old-growth stand attributes (i.e., high stand basal area, maximum tree diameter, variability of tree diameters, and density of large Douglas-fir trees) appears to have been slowest on steeper slopes, wetter aspects, and higher elevations.

Download or read book Juvenile Development of Douglas fir Red Alder and Snowbrush Associations in Western Oregon written by Babiker Ahmed El Hassan and published by . This book was released on 1967 with total page 104 pages. Available in PDF, EPUB and Kindle. Book excerpt: The juvenile development of Douglas-fir, red alder and snowbrush associations was investigated in western Oregon. The relationship between Douglas-fir and red alder was studied and compared in the Coast, Willamette Valley and Cascade regions. Snowbrush- Douglas-fir stands were sampled in the western Cascades. Alder- Douglas-fir relationships were studied on clearcuts supporting at the same time mixtures of alder and Douglas-fir and open-grown Douglas-fir. Sites where snowbrush and Douglas-fir grew together were selected on the same basis. Total heights of alder and Douglas-fir were expressed as cumulative one-year growth measurements. Canopy height of snowbrush was measured at various ages to determine growth rate. Information pertaining to moisture, vegetation, slope, aspect, elevation and stand structure was recorded at each sample plot. The data were analyzed with the aid of a multiple regression program. Height and (height)2 were treated as independent variables, and annual height increment as the dependent variable. Results indicate that early establishment of Douglas-fir is expected to aid its dominance-takeover and allow it to evade suppression by red alder. Douglas-fir trees growing on wet sites need to be established earlier than those on drier habitats for the same degree of suppression evasion. The rapid juvenile growth rate of red alder is a major threat for the successful establishment of Douglas-fir. Height growth curves of the two species intersected at an earlier age on non-wet as compared to wet sites. The two trees grow in direct competition up to about age 40 years on wet habitats, with alder able to suppress Douglas-fir during this period. Douglas-fir has virtually no chance of survival when it is established concurrently with red alder or after its appearance. Snowbrush retards the growth of Douglas-fir trees during their first ten years of development. Trees that are delayed more than five years in establishment suffer a loss of more than 50% in total height as a result of the suppressive effect of the shrub. It is expected that the trees will compensate for some of this loss, but their growth may never equal that of comparable open-grown Douglas-fir developing under similar conditions.