Download or read book Influence of Artificial Canopy Gaps on Wildlife and Understory in Young Coastal Temperate Coniferous Forests of the Pacific Northwest written by Landon James Charlo and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Understory Plant Development in Artificial Canopy Gaps in an 81 year old Forest Stand on Chichagof Island Southeast Alaska written by Scott Howard Harris and published by . This book was released on 2017 with total page 25 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Spatial Distribution of Understory Vegetation in Tree Canopy Gaps of the Pacific Northwest written by Sharon Gail London and published by . This book was released on 1999 with total page 208 pages. Available in PDF, EPUB and Kindle. Book excerpt: Understory vegetation in artificially created tree canopy gaps in the Pacific Northwest was studied to determine 1) variation in understory vegetation cover between gap edges and gap centers, as well as between control and treatment plots, 2) spatial patterns of biomass and difference in biomass patterns among plots, 3) individual species responses to gap creation and 4) the relationships between species dominance and diversity by site and treatment. Data were collected in 1990 and 1997 in 16 plots (two controls and two treatments at each of four study sites: the H.J. Andrews Experimental Forest and Martha Creek, Panther Creek, and Trout Creek in the Wind River Experimental Forest). Two of the sites are oldgrowth stands (250-500 years old), while the other two sites are mature stands (90- 150 years old). Six growing seasons after gap creation, average percent cover of understory vegetation was greater within gaps than at gap edges. Vegetation cover had increased significantly in all artificial gaps, and it had increased more in gaps than in controls. Vegetation cover increased more at Martha Creek, a mature stand, than at H.J. Andrews and Trout Creek, the two old-growth stands, or at Panther Creek, a mature stand. Understory biomass increased more in gaps than in controls and the amount of increase varied by site. Initial understory biomass was highest in Panther Creek and Martha Creek, but the magnitude of biomass increase was greatest in Trout Creek and H.J. Andrews. Biomass patterns in 1990 and 1997 were more patchy in old-growth stands than in mature stands. Vegetation cover of most understory species increased from 1990 to 1997 in artificial gaps, but species' responses were often site specific. In some cases, species with advantageous dispersal mechanisms (such as rhizomes, stolons, or clonal growth, e.g. Rubus ursinus, or Acer cinncinatum) increased in cover and biomass more than species without such advantageous dispersal mechanisms. Cover of weedy species such as Epilobium angustfolium and Lactuca muralis increased dramatically (up to 25 times) in artificial gaps, but weedy species represented less than two percent of the total average cover in 1997. Species dominance and diversity did not respond consistently following gap creation. Species dominance was relatively high (species with highest dominance was 30 g/m2) and diversity relatively low (38 species) at Martha Creek, a mature stand, whereas species dominance was low and diversity high at H.J. Andrews (9 g/m2, 51 species), an old-growth site. Panther Creek, a mature stand, and Trout Creek, an old growth stand, had intermediate dominance and high diversity (17 g/m2, 57 species at Panther Creek and 18 g/m2, 41 species at Trout Creek).

Download or read book Patterns in Understory Vegetation Communities Across Canopy Gaps in Young Douglas fir Forests of Western Oregon written by Robert T. Fahey and published by . This book was released on 2005 with total page 300 pages. Available in PDF, EPUB and Kindle. Book excerpt: Canopy gap formation is a major factor contributing to maintenance of overstory species diversity and stand structure in forests and may be integral to development of understory shrub and herb layers as well. Acknowledgement of gap formation as a fundamental feature of natural forests has led to consideration of gaps as an option in forest management regimes. This study examined understory vegetation communities across canopy gaps created as a part of the Density Management Study (DMS), which investigates the effectiveness of a thinning regime in promoting late-successional habitat development in young Douglas-fir forests of western Oregon. Patterns in understory vegetation community composition in and around 0.1 and 0.4ha gaps created as a part of the DMS treatment were investigated. The primary goal of this research was to investigate the potential role of canopy gap creation in fostering heterogeneity in understory vegetation communities, and to examine the extent of gap influence on the surrounding thinned forest matrix. Tree species distributions have been shown to partition across gaps in tropical forest systems through differential responses of species to gradients in resource availability, a pattern known as gap partitioning. In temperate forests, understory vegetation communities are much more diverse than the overstories, and display a greater array of habitat requirements. Therefore, understory communities may be more likely than overstories to exhibit gap partitioning in these forests. Patterns in understory community composition across gaps suggest that gap partitioning has occurred. The strength of this partitioning effect appears to differ between gap sizes, as smaller gaps showed a less powerful effect. Abundance of ruderal species was strongly related to gap partitioning in larger gaps, while smaller gaps were dominated by competitor species. Partitioning may be related to an interactive relationship between harvest-related ground disturbance and resource gradients. Therefore, considerations of gap partitioning processes should take into account intensity and spatial distribution of ground disturbance in relation to resource gradients. In addition, conditions necessary for the expression of gap partitioning in understory vegetation communities may be rare in natural gaps in this region. The influence of gaps on understory vegetation communities in the surrounding forest appears to be relatively small. This small influence extent may help explain the lack of a stand level response to gap formation in these stands. Larger gaps exhibit a slight influence on the understory plant community in the surrounding forest to the north of the gap. In small gaps, there seemed to be an influence of the surrounding forest on gap interiors, resulting in an area of influence smaller than the physical gap area. This relationship may indicate that the area of gap influence on understory vegetation may not scale linearly with physical gap size. Species diversity was higher in gap interiors than in surrounding thinned forests. However this effect was partially due to the presence of exotic species, which showed an affinity for gap interiors. Late successional associated species were negatively related to gap interiors, but only in the larger gap size. Gap creation appears to be promoting small scale species diversity in these stands, but creation of large gaps may also promote the establishment of exotic species and may have a negative effect on late successional associated species. However, any and all of these effects may be transient, as understory communities will be strongly affected by overstory re-establishment, and related changes in resource availability. In general, gap formation may influence small-scale stand heterogeneity as evidenced by understory plant communities, but this effect may rely strongly on the nature of gap formation and intensity of disturbance related to this formation.

Download or read book Forest Canopy Sturcture in Western Oregon written by Anne C. S. Fiala and published by . This book was released on 2003 with total page 670 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterization of canopy structure, the horizontal and vertical distribution of the tree crowns in a forest, is important for the management of forests in the Pacific Northwest. The canopy is an important habitat element for many wildlife species, canopy structure affects understory development, and influences various natural processes, such as the intensity of propagation of wildfire. Thus, improving our understanding of canopy structures and trends can aid forest management. The overall goal of this study was to characterize vertical and horizontal canopy structure for multiple forest groups in western Oregon. The specific objectives were to: 1) characterize vertical and horizontal canopy structure for dominant forest types in western Oregon, 2) evaluate methods for measuring canopy cover and structure, 3) compare methods to predict forest canopy cover and vertical diversity using standard inventory measurements, and 4) predict bird species occurrence with different canopy diversity measures. I evaluated patterns of vertical and horizontal canopy structure and understory cover along a successional gradient using 934 forested plots in western Oregon. Observed data were from the USDA Forest Service Forest Inventory and Analysis (FIA) program from the 1995-97 survey on private and non-federal public lands. Patterns were examined for wet-conifer, wet-hardwood, and dry-hardwood forests. The upper tree canopy layer contributed the most to total cover except in the dry-hardwood stands, where the vertical distribution of tree cover was more evenly distributed. However, mean canopy cover rarely exceeded 85%, even in productive young conifer forests. Shade-tolerant species rarely made up more than 20% of canopy cover, even in the lower canopy layers and in stands> 100 yrs old. Contrary to expectations, percent cover of understory shrubs and herbs was not substantially lower in young closed-canopy stands than in other stands. Ground-based measures of canopy cover on inventory plots were compared to predictions with regression models that regressed canopy cover on standard forest measurements, with estimates from aerial photography, and predictions with the forest vegetation simulator (FVS) program. Model predictions from inventory measurements were within 15% of measured cover for> 82% of the observations. Standard inventory estimates of cover using 1:40,000 scale aerial photos were poorly correlated with ground-measured cover, especially in wet-hardwood (r=0.58) and dry-hardwood (r0.61) stands. FVS tended to underestimate cover by up to 50% in wet-conifer and wet-hardwood stands. The aerial photos and FVS equations used in this study are not recommended as surrogates for ground-based measurements of cover. However, the level of accuracies of the predictive models developed in this study may be adequate for some purposes. I compared fourteen measures of vertical structural diversity and layering using the inventory plots. I then attempted to predict selected vertical diversity indices from standard forest variables. Simpson's diversity index on tree heights best differentiated among the range of vertical structure classes of the inventory plots. I developed predictive equations for Simpson's height diversity index (SDI), Foliage Height Diversity (FHD), and Canopy Height Diversity Index (CHDI), which used basal area, standard deviation of dbh, and stem frequency of size classes as the best variables. Predicted SDI values were within 0 15 units of calculated SDI for> 79% of the observations, predicted CHDI values were within 1.5 units for> 91% of the observations, except in the dry-hardwood stands (only 69%), and predicted FHD measures were within 0.2 units for> 85% of the observations among forest groups. The equations for FHD and SDI were applied to a wildlife-habitat database for western Oregon to determine if classification efficiency of existing models using CHDI to predict presence of bird species could be improved. The classification efficiency of bird-habitat association models improved for 33% and 66% of models for the Oregon Coast Range with the FHD and SDI variables, respectively. Models with FHD and SDI had improved classification efficiency for 18% of Cascade Range models. Although improvements in classification efficiency were less than six percentage points, future use of these diversity indices is warranted in place of CHDI when estimates of FHD and/or SDI are available and CHDI estimates are not. Four ground-based techniques for estimating forest overstory cover - line-intercept, spherical densiometer, moosehorn, and hemispherical photography - and estimates generated using FVS were compared across a range of stand structure types. Canopy cover estimates for the four ground-based methods were not correlated with structure type. Differences among estimates of cover using FVS and the other methods did depend on the forest structure type. Differences among ground-based methods were primarily related to differences in angle of view. Although the line-intercept had the narrowest angle of view, the moosehorn provided the most conservative estimates of overstory cover. Regression equations were derived to allow conversion among canopy cover estimates developed with the four ground-based methods. The FVS calculated cover should not be used as a substitute for ground-based measures in these forest types given that it was consistently much lower (up to 70%) than estimates from the ground-based methods within each forest-structure type. Overall, this study provides researchers and forest managers with new information and tools that can be applied across the forested landscape of Oregon. Models to predict canopy cover and diversity, and bird habitat can be substituted for field studies, assuming the accuracies of predictions are adequate for desired purposes. In field studies where ground-based cover measures are needed, the moosehorn is recommended as the most conservative estimator of cover. For more detailed canopy data, the line-intercept method is warranted. Modifying the line-intercept method to use fixed height intervals may be preferable to the use of three relative layers. This adjustment will allow for more direct comparisons of canopy cover of layers among stands.

Download or read book Influence of Deciduous Tree Representation on Understory Plant Communities in Pacific Northwest Forests written by Dano Holt and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: While broadleaf deciduous trees are historically a consistent component of forest canopy composition, the ecological importance of these trees has been understudied, in particular their impact on understory plant communities. Broadleaf deciduous trees are a unique source of functional diversity in the Pacific Northwest's conifer dominated forests, and have been shown to alter soil nutrients, precipitation reaching the forest floor, epiphytic communities and provide critical habitat for a number of dependent wildlife species. However, their impact on understory plant communities has remained understudied. In particular, as one of the key functional differences in coniferous and broadleaf trees in the Pacific Northwest is a deciduous leaf habit which increases light transmission in the fall through winter, their impact on light availability to the understory has remained under investigated. It was hypothesized that understory plants growing beneath deciduous trees would be exposed to more light. This study investigated understory plant communities growing under overstory canopies of highly coniferous, low deciduous or highly deciduous compositions. Hypotheses were that 1) understory plant communities will differ significantly from communities under stands with differing overstory percent deciduousness, and that there would be changes to understory plant community diversity and 2) commonly occurring generalist species be acclimated to higher light availability in terms of functional traits, including specific leaf area (SLA), leaf area (LA), rachis angle (in Polystichum munitum), light compensation point (LCP), light response curves, saturation point (K) and intrinsic water use efficiency (iWUE). Understory community composition sampling indicated that canopy composition type had a significant effect on understory community, as indicated by a PERMANOVA test. Additionally, there were a number of species that only occurred under either highly coniferous or highly deciduous canopies. Results from functional trait sampling indicated that for the majority of traits generalist species including Acer circinatum, Berberis nervosa and Polystichum munitum exhibited changes to functional traits indicating that highly deciduous plots were higher light plots. Not only were understory communities growing under highly deciduous canopies significantly differ from those growing beneath low deciduous or highly coniferous canopies, but there were changes to morphology and physiology of plants under differing canopy types. These results suggest that broadleaf deciduous trees in the Pacific Northwest have a functional impact on heterogeneity of the understory environment and consequently the understory plant communities. These results imply that broadleaf deciduous trees play an important role in structuring forests in the Pacific Northwest, and their impact should be assessed in both forest management and conservation purposes.

Download or read book Understory Tree Response to Canopy Gaps in Old growth Douglas fir Forests of the Pacific Northwest written by Robert Van Pelt and published by . This book was released on 1995 with total page 474 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Canopy Structure on Forest Lands in Western Oregon written by United States Department of Agriculture and published by CreateSpace. This book was released on 2015-02-14 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Canopy structure is an important attribute affecting economic and ecological values of forests in the Pacific Northwest. However, canopy cover and vertical layering are rarely measured directly; they are usually inferred from other forest measurements. In this study, we quantified and compared vertical and horizontal patterns of tree canopy structure and understory cover along a successional gradient of forests and among stands with different thinning histories on nonfederal lands in western Oregon. Analyses focused on three dominant forest type groups: wet conifer, wet hardwood, and dry hardwood. We used data from 917 systematically located, forested Forest Inventory and Analysis plots measured between 1995 and 1997. On each plot, canopy cover by layer and species was measured on line-intercept transects, and cover of understory species was measured on five subplots. Trends in canopy structure with stand age did not always follow the patterns predicted by common successional models. Most of the cover in moist stands was in the upper tree layer, but cover in dry hardwood stands was more evenly distributed among layers. Contrary to expectations of canopy closure, mean canopy cover by age class rarely exceeded 85 percent, even in unthinned productive young conifer forests. Possibly as a result, effects of stand age on understory vegetation were minimal, except for low levels of forbs found in 20- to 40-year-old wet conifer stands. Shadetolerant tree species rarely made up more than 20 percent of canopy cover, even in the lower canopy layers and in stands >100 years old. Although heavily thinned stands had lower total cover, canopy structure did not differ dramatically between thinned and unthinned stands. Our findings suggest potential limitations of simple stand succession models that may not account for the range of forest types, site conditions, and developmental mechanisms found across western Oregon.

Download or read book Responses of Southeast Alaska Understory Species to Variation in Light and Simulated Herbivory written by Thomas A. Hanley and published by . This book was released on 2014 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Special Issue on Northwest Forest Canopies written by David Carl Shaw and published by . This book was released on 1996 with total page 116 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Canopy Structure on Forest Lands in Western Oregon written by Anne C. S. McIntosh and published by . This book was released on 2009 with total page 35 pages. Available in PDF, EPUB and Kindle. Book excerpt: Canopy structure is an important attribute affecting economic and ecological values of forests in the Pacific Northwest. However, canopy cover and vertical layering are rarely measured directly; they are usually inferred from other forest measurements. In this study, we quantified and compared vertical and horizontal patterns of tree canopy structure and understory cover along a successional gradient of forests and among stands with different thinning histories on nonfederal lands in western Oregon. Analyses focused on three dominant forest type groups: wet conifer, wet hardwood, and dry hardwood. We used data from 917 systematically located, forested Forest Inventory and Analysis plots measured between 1995 and 1997. On each plot, canopy cover by layer and species was measured on line-intercept transects, and cover of understory species was measured on five subplots. Trends in canopy structure with stand age did not always follow the patterns predicted by common successional models. Most of the cover in moist stands was in the upper tree layer, but cover in dry hardwood stands was more evenly distributed among layers. Contrary to expectations of canopy closure, mean canopy cover by age class rarely exceeded 85 percent, even in unthinned productive young conifer forests. Possibly as a result, effects of stand age on understory vegetation were minimal, except for low levels of forbs found in 20- to 40-year-old wet conifer stands. Shade-tolerant tree species rarely made up more than 20 percent of canopy cover, even in the lower canopy layers and in stands >100 years old. Although heavily thinned stands had lower total cover, canopy structure did not differ dramatically between thinned and unthinned stands. Our findings suggest potential limitations of simple stand succession models that may not account for the range of forest types, site conditions, and developmental mechanisms found across western Oregon.

Download or read book Final Supplement to the Environmental Impact Statement for an Amendment to the Pacific Northwest Regional Guide Spotted owl guidelines written by United States. Forest Service. Pacific Northwest Region and published by . This book was released on 1988 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: Siskiyou County Library has vol. 1 only.

Download or read book Draft Supplement to the Environmental Impact Statement for an Amendment to the Pacific Northwest Regional Guide written by United States. Forest Service. Pacific Northwest Region and published by . This book was released on 1986 with total page 238 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Impact of Gap Size on Environmental Conditions Survival and Early Growth of 5 Pacific Northwest Species written by Meike Liv Buhaly and published by . This book was released on 2021 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: The formation of forest gaps and their resulting size and shape is highly variable across forest types and can produce a wide range of patterns in seedling establishment. The impact of gap size on microclimate and seedling growth and survival after planting, specifically in mixed-species stands is poorly studied. This study examines the influence of gap size on the light environment, soil moisture distribution, and understory vegetation dynamics and in turn, how these environmental characteristics effect seedling survival, health, and growth of 5 Pacific Northwest native tree species with varying shade and drought tolerances. More than 5000 seedlings were planted in groups of 5 individuals, both monoculture and mixed-species pentads, across 16 clear-cut plots of 4 sizes (0.05, 0.1, 0.25, and 0.5 ha). Larger gaps were found to have higher light and lower vegetation cover, while gap size had no influence on soil moisture. Initial mortality of conifer species was largely determined by high soil moisture in dense, clay soils, specifically in the most downslope row of gaps. Douglas-fir (26.8%) and western hemlock (27.9%) mortality was significantly higher than western redcedar (5.0%), red alder (6.9%), and grand fir (8.1%) mortality. Chlorophyll fluorescence tracked over summer drought months suggested that as soils became drier, seedling health improved for all species. Environmental predictors of growth differed by species but were consistently influenced by abiotic factors soil moisture and light as well as biotic factors vegetation and ungulate browse. Increasing soil moisture and light led to positive growth for all species except western hemlock which was not significantly impacted. Increased height of surrounding understory vegetation led to reductions in basal area increment in western redcedar (Thuja plicata), western hemlock (Tsuga heterophylla), Douglas-fir (Pseudotsuga menziesii), and grand fir (Abies grandis). Western hemlock and western redcedar saw increased growth as vegetation cover increased until full coverage where growth then decreased. Red alder (Alnus rubra), western redcedar, and western hemlock were significantly impacted by ungulate browse which occurred in half of western redcedar and red alder seedlings. Western redcedar saw an increase in basal area increment in response to browse while red alder and western hemlock saw reductions in height. No influence of surrounding seedling competition was found two years post planting. Overall, gap size impacts both abiotic and biotic environmental characteristics and these differing microclimates resulted in varying seedling growth and survival among species. Further research in this long-term experimental site is necessary to determine when mixed-species plantings begin interacting and how these interactions are influenced by gap size and shifts in microclimate.

Download or read book Transpiration and Canopy Conductance of Mixed Species Conifer Stands in an Inland Pacific Northwest Forest written by Robert Earl Pangle and published by . This book was released on 2008 with total page 354 pages. Available in PDF, EPUB and Kindle. Book excerpt: During 2004 and 2005, we examined the influence of increasing tree height on canopy level stomatal conductance and transpiration in five tree species growing in mixed coniferous forests located in northern Idaho, USA. In a replicated study involving nine stands of varying height, we measured stem sap-flux rates in 50 trees that ranged in height from 4.8 to 42.7 m. Across the 2-year sampling period, we observed significant decreases in leaf-level canopy conductance (GS) with increasing tree height for the Larix occidentalis, Pinus monticola, and Tsuga heterophylla trees in our study. We also observed decreases in canopy conductance (GS) with increasing height in Thuja plicata, but the rate of decline was not statistically significant. We did not observe a decline in canopy GS across the 2-year sampling period in the Pseudotsuga menziesii var. glauca trees that we measured. Specifically, across all species and years, daily mean GS averaged 28.9 (3.0), 21.9 (1.9), and 19.1 (1.5) mmol m−2s−1 respectively for the short, intermediate, and tall height class trees in our study. Our observations of declining GS with increasing tree height are in agreement with a central tenet of the hydraulic limits hypothesis, which predicts decreased leaf level stomatal conductance as hydraulic resistance in the xylem pathway increases with tree height.

Download or read book Using Artificial Canopy Gaps to Restore Avian Habitat in Tropical Timber Plantations written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The potential for plantations to catalyze forest regeneration on highly degraded land and the need to research management methods to increase biodiversity within plantations have been widely recognized. Our study investigated the effects of creating artificial canopy gaps by girdling exotic timber trees in plantations on the germination, growth, and survival of native tree species that may be important food plants for the Puerto Rican parrot. We found that seedling growth increased significantly in gaps; there were no differences in survival or germination between gap and closed plots. Percentage cover of grasses, shrubs, and vines increased but did not prevent tree seedlings from growing significantly more in gaps. Leaf litter removal had no effect on germination, growth, or survival. Both local and landscape level diversity is predicted to increase in gaps if large saplings present in the understory replace the girdled timber trees, but plantations will still be dominated by exotics and timber species. Our results suggest that restoration of native forest diversity in plantations will require continued management to remove exotic species and promote growth of tree species with high wildlife habitat value.

Download or read book Environmental Issues in Pacific Northwest Forest Management written by Committee on Environmental Issues in Pacific Northwest Forest Management and published by National Academies Press. This book was released on 2000-07-28 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: People are demanding more of the goods, services, and amenities provided by the forests of the Pacific Northwest, but the finiteness of the supply has become clear. This issue involves complex questions of biology, economics, social values, community life, and federal intervention. Forests of the Pacific Northwest explains that economic and aesthetic benefits can be sustained through new approaches to management, proposes general goals for forest management, and discusses strategies for achieving them. Recommendations address restoration of damaged areas, management for multiple uses, dispute resolution, and federal authority. The volume explores the market role of Pacific Northwest wood products and looks at the implications if other regions should be expected to make up for reduced timber harvests. The book also reviews the health of the forested ecosystems of the region, evaluating the effects of past forest use patterns and management practices. It discusses the biological importance, social significance, and management of old-growth as well as late-succession forests. This volume will be of interest to public officials, policymakers, the forest products industry, environmental advocates, researchers, and concerned residents.