Download or read book Drought Responses Across Diverse Conifer Species Habitats and Competitive Gradients in Northern California written by Gabriel J. Roletti and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Frequent and intense drought events are rapidly altering stand dynamics in western North American forests. Climate, competition, and site characteristics can affect the growth responses of individual trees to drought stress. The ecological and geographical diversity of northern California provides a unique opportunity to measure these responses across species, habitat types, and levels of competitive pressure. This study used dendrochronological techniques and linear mixed-effects models to assess growth responses to drought in four montane and two coastal conifer species across 54 study sites (nine sites per species and 540 trees total) in northern California. Growth was evaluated from 2002-2018 and the drought period was from 2013-2015. There were significant differences among species and environments (coastal or montane) in growth, drought resistance and resilience, and annual latewood proportion. Growth in montane species was generally positively correlated with moisture availability (Palmer Drought Severity Index) and negatively correlated with competitive pressure. The four montane species maintained relatively stable drought resistance, resilience, and latewood proportion across the study period. In contrast, growth in the two coastal species was influenced more by tree size and crown ratio than moisture availability or competition. As the 2013-2015 drought proceeded, coastal species showed marked reductions in drought resistance and resilience and increases in latewood proportion. The six focal species endured this drought in northern California with reasonably high resistance and resilience. However, the lower resistance observed in coastal species suggests that they may be at risk for increased stress and mortality in the event of more severe, prolonged, and/or frequent droughts.
Download or read book Influences on Conifer Drought Responses in Northern California written by Wallis L. Robinson and published by . This book was released on 2021 with total page 102 pages. Available in PDF, EPUB and Kindle. Book excerpt: California is experiencing increasingly severe and prolonged droughts, which are contributing to changes in tree stress and forest mortality. Many factors affect a tree’s drought response, including competition, climate, and site and tree characteristics. Northern California provides a suitable venue to explore the effects of these factors, as it spans a variety of site conditions and includes habitat for conifers with different adaptations and requirements. This study used annual 13C discrimination and growth metrics to assess differences in drought resistance and resilience in conifers adapted to coastal and montane ranges at both wet and dry sites, as well as differences in environmental factors that affect species-level drought responses. Coastal species (Sitka spruce and western hemlock) were more sensitive to drought than montane species (Shasta fir, Brewer spruce, sugar pine, and western white pine). Coastal trees were more sensitive to drought at dry sites than wet sites. Montane species exhibited smaller differences in drought resistance between wet and dry conditions, but varied in factors contributing to physiological response among species. This study suggests that in most situations, conifers in northern California weathered the 2012 – 2016 drought with reasonably high resistance and resilience. However, many of these trees may be at risk for increased stress and mortality in the event of longer and/or more frequent, severe drought. Management strategies for conifers in one region may not be suitable for the same species in another region, and the effects of competition and community composition on drought resistance and resilience must be carefully considered.
Download or read book Drought Tree Mortality and Regeneration in Northen California written by Sophia Lemmo and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The 2012-2016 California drought was the most severe in the state’s recorded history, contributing to the death of millions of trees. While the effects of this drought on forests are relatively well studied in the central and southern Sierra Nevada, less is known about its effects on the heavily timbered and diverse forests of northern California. Through sampling 54 0.25 ha plots in northern California, this study compared tree mortality and regeneration patterns before, during, and after California’s most recent record-setting drought. This study evaluated 1) the influence of habitat and competitive covariates on mortality and regeneration trends using ridge regression analysis; and 2) tree death and seedling/sapling establishment dates using dendrochronology and Superposed Epoch Analysis to explore the influence of climate on forest demographics. Montane drought-induced tree mortality occurred primarily in trees smaller than 40 cm diameter at breast height (DBH), with no coastal drought-related mortality in trees with DBH greater than 80 cm. The highest rates of overstory mortality across all sites were observed in Abies grandis (51%), Pinus lambertiana (43%), and Pinus monticola (37%). Picea breweriana (6%) and Picea sitchensis (9%) had the lowest average mortality rates. In montane environments, years with high rates of mortality were positively associated with climatic water deficit (CWD; drier than expected conditions) in the 1-2 years preceding and during tree death dates. Pre-drought montane mortality was greater at wet sites than dry sites, and recent montane mortality (~2013-2020) was positively related with canopy openness. In coastal environments, recent tree mortality was positively associated with maximum temperature and topographic position. Regeneration was dominated by advanced regeneration (median age of 32 years) of shade-tolerant species. In montane environments, regeneration dates were significantly associated with lower-than-average CWD the year proceeding. In coastal environments, regeneration was greater at dry sites than wet sites, and was positively associated with stand density and maximum temperature. These data demonstrate that these forests are not actively perpetuating as diversely into the future, especially in montane environments where more mortality is found in white pine species (Pinus lambertiana and P. monticola) and where the regeneration is weighted towards advanced regeneration of shade-tolerant fir species. This work indicates a need to implement targeted management aimed at generating disturbances to foster balanced and responsive regeneration. This management should preferentially retain medium to larger trees, as these size classes seem to be the least vulnerable to mortality. Such management would be promising for supporting the resilience and diversity of northern California landscapes.
Download or read book Ecosystems of California written by Harold Mooney and published by Univ of California Press. This book was released on 2016-01-19 with total page 1008 pages. Available in PDF, EPUB and Kindle. Book excerpt: This long-anticipated reference and sourcebook for CaliforniaÕs remarkable ecological abundance provides an integrated assessment of each major ecosystem typeÑits distribution, structure, function, and management. A comprehensive synthesis of our knowledge about this biologically diverse state, Ecosystems of California covers the state from oceans to mountaintops using multiple lenses: past and present, flora and fauna, aquatic and terrestrial, natural and managed. Each chapter evaluates natural processes for a specific ecosystem, describes drivers of change, and discusses how that ecosystem may be altered in the future. This book also explores the drivers of CaliforniaÕs ecological patterns and the history of the stateÕs various ecosystems, outlining how the challenges of climate change and invasive species and opportunities for regulation and stewardship could potentially affect the stateÕs ecosystems. The text explicitly incorporates both human impacts and conservation and restoration efforts and shows how ecosystems support human well-being. Edited by two esteemed ecosystem ecologists and with overviews by leading experts on each ecosystem, this definitive work will be indispensable for natural resource management and conservation professionals as well as for undergraduate or graduate students of CaliforniaÕs environment and curious naturalists.
Download or read book Conifers of California written by Ronald M. Lanner and published by . This book was released on 1999 with total page 316 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Exploring the Effects of Heat and Drought on Conifer Trees written by Michael W. Jenkins and published by . This book was released on 2016 with total page 139 pages. Available in PDF, EPUB and Kindle. Book excerpt: Periods of low precipitation and increasing atmospheric temperature are having adverse effects on tree and forest growth and survival in part via limitations upon photosynthesis. Understanding how different species and plant functional types will physiologically respond to the combination of drought and heat is therefore critical for modeling and predicting the fate of trees and forests under future climate conditions. In addition, climate is changing at a faster pace than the slow natural adjustment rates of most species to their rapidly shifting habitat conditions, especially for long-lived tree species, which poses a major challenge for management, conservation, and preservation strategies and policies. Therefore the current traditional conservation/preservation methods, such as providing migration corridors and increasing suitable habitat at range margins will need to be supplemented with a more direct, innovative, and adaptive approach. One such approach is that of managed migration, which is the intentional translocation of species outside their current habitat in order to reduce anticipated loss of biodiversity caused by climate change related stress. This dissertation addresses these problems through the experimental examination of heat, drought, and the combination of heat and drought on two conifer species that have differing drought tolerances, which can serve as global models for a range of physiological mechanisms to deal with water and heat stress, as well as a social science investigation into the preservation of an iconic conifer tree, the coast redwood into Oregon via managed migration.
Download or read book Stand Dynamics During Drought written by Samuel W. Flake and published by . This book was released on 2016 with total page 218 pages. Available in PDF, EPUB and Kindle. Book excerpt: Widespread dieoff of trees associated with severe drought is a recent global phenomenon of increasing conservation and management concern. Tree dieoff is likely to produce dramatic and widespread alterations to plant community composition and successional dynamics, with associated changes in nutrient cycling, hydrology, and wildlife habitat. In order to predict and manage the effects of future widespread drought, there is a need for greater understanding of both the causes of drought-associated tree mortality as well as the subsequent effects of mortality on tree regeneration and understory dynamics. In this study, we investigated the effects of climate, stand structure, and insect herbivores on tree mortality and canopy dieback of semi-arid pinyon-juniper woodlands, as well as the implications of woodland overstory mortality on the abundance of juvenile trees and the distribution of understory plants. In 2015 we resampled 102 plots in a permanent plot network established in 2005 spanning pinyon-juniper woodlands in eleven mountain ranges in central Nevada, encompassing strong gradients of topography, elevation, soil conditions, and aridity. Using individually-tagged trees, we measured tree survival and changes to canopy greenness. In order to assess the effects of neighborhood tree density on changes in tree canopy health, we recorded high-precision GPS locations for each tree and calculated the basal area of neighboring trees and the distance to the nearest neighbor. We measured tree regeneration in two size classes: seedlings (20 cm tall) and sapling (20cm tall). We also measured understory cover by species in 1-m2 quadrats. We noted the microhabitat of tree juveniles and quadrats in order to assess the importance of fine-scale microhabitat heterogeneity to understory dynamics. This study is the first to document widespread dieoff and canopy decline in Great Basin pinyon-juniper woodlands in response to recent severe drought. We found mortality was most strongly predicted by high growing-season vapor pressure deficit and low winter precipitation (Forest Drought Stress Index), while canopy decline was most closely associated with cumulative climatic water deficit. Trees in sites with deeper soils also experienced greater health declines. Stand structure had a smaller, but significant, effect on tree survival and canopy health, with trees in dense 4-m neighborhoods and those with close neighbors experiencing increased mortality risk and canopy dieback. As predicted, the regeneration of pinyon pine was strongly influenced by changes to the overstory trees. Both seedlings and saplings were positively associated with plot-level dead tree basal area and with fine-scale mortality-associated microhabitats, suggesting that drought mortality may create canopy gaps with increased recruitment. In contrast to microhabitat results, pinyon seedlings were much more abundant in stands with lower levels of canopy dieback and in stands with more live basal area, suggesting that new recruitment may be limited by reduced seed availability. The dynamics of tree regeneration in woodlands will likely depend upon seed availability, resource levels, timescale, and the abundance and spatial arrangement of larger juveniles (advance regeneration) present before the drought. We found little evidence of response to tree mortality for most understory plant functional types. However, Poa secunda and Bromus tectorum were both more abundant than expected in mortality-associated microhabitats. At a plot scale, Bromus tectorum abundance was positively associated with canopy dieback, and has increased in dominance since 2005 in arid sites with high levels of dieback. While some native species may respond positively to resources released by tree mortality, there is a risk of invasion and increasing dominance of cheatgrass under future droughts, underlining the importance of understanding overstory-understory interactions in arid woodlands. This study highlights the need for further research into the effects of within-stand structural heterogeneity on woodland responses to drought. Pinyon-juniper woodlands have a complex, patchy distribution of trees which likely affects the ways in which competition may predispose trees to drought mortality. Overstory mortality creates heterogeneous microhabitats which alter the distribution of juvenile trees as well as understory species, thus spatially structuring the response of these species to drought. Aridity and severe drought are likely to increase in coming decades, and understanding the complex interactions that drive woodland tree mortality and the subsequent understory response is critical to the effective management of resilient woodlands.
Download or read book The Genomic Basis of Adaptation to Climate Across Oak Quercus Species and Populations in California written by Alayna Mead and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Characterizing the genomic basis of climate adaptation is essential both for understanding the process of evolution and for conserving populations under climate change. Here, I use several methods to investigate the genomic basis of adaptation across oak species and populations. In Chapter 1, we compared the gene expression response to a simulated drought stress across six oak species, two species from each of the three taxonomic sections of Quercus in California, which varied in their drought tolerance. We found that drought tolerant species had a less plastic response to leaf drying, suggesting that phenotypic traits and non-plastic patterns of gene expression contribute to their drought tolerance more than plasticity. We also found that the two deciduous trees, which were the most drought sensitive species, responded to drying with 22% of the same genes, indicating these responses had evolved in parallel across distantly related clades. In Chapter 2, we used whole-genome sequencing to characterize the rangewide genetic structure of a rare island endemic oak species, Quercus tomentella, from the California Channel Islands and Guadalupe Island in Mexico. We found evidence for widespread hybridization with a related oak species, isolation of the Guadalupe Island trees, and some gene flow among the California islands that is likely mediated by wind pollination. We also identified putatively adaptive SNPs that were associated with climate variables, compared the spatial patterns of neutral SNPs and candidate SNPs, and used this information to make recommendations for choosing seed sources for restoration projects in the light of climate change. In Chapter 3, we characterized the heat stress response across species and populations. We performed a heat wave experiment and compared the gene expression responses among three oak species and two populations within each species, one from a southern, warmer site and one from a northern, cooler site. We found shared responses to heat stress among all species and populations, including the responses of individual genes as well as genes with related functions. We found limited evidence of differences in stress response among populations, suggesting a lack of local adaptation in the plastic heat stress response.
Download or read book Biology and Management of the Western Gray Squirrel and Oregon White Oak Woodlands written by Loreen A. Ryan and published by . This book was released on 1995 with total page 44 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Causes and Consequences of Species Diversity in Forest Ecosystems written by Aaron M. Ellison and published by MDPI. This book was released on 2019-07-30 with total page 274 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue Causes and Consequences of Species Diversity in Forest Ecosystems that was published in Forests
Download or read book Ecological Society of America Annual Meeting Abstracts written by Ecological Society of America. Meeting and published by . This book was released on 2005 with total page 788 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Plant Responses to Drought Stress written by Ricardo Aroca and published by Springer Science & Business Media. This book was released on 2012-10-12 with total page 460 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a comprehensive overview of the multiple strategies that plants have developed to cope with drought, one of the most severe environmental stresses. Experts in the field present 17 chapters, each of which focuses on a basic concept as well as the latest findings. The following major aspects are covered in the book: · Morphological and anatomical adaptations · Physiological responses · Biochemical and molecular responses · Ecophysiological responses · Responses to drought under field conditions The contributions will serve as an invaluable source of information for researchers and advanced students in the fields of plant sciences, agriculture, ecophysiology, biochemistry and molecular biology.
Download or read book Effects of Drought on Forests and Rangelands in the United States written by James M. Vose and published by . This book was released on 2016 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: This assessment provides input to the reauthorized National Integrated Drought Information System (NIDIS) and the National Climate Assessment (NCA), and it establishes the scientific foundation needed to manage for drought resilience and adaptation. Focal areas include drought characterization; drought impacts on forest processes and disturbances such as insect outbreaks and wildfire; and consequences for forest and rangeland values. Drought can be a severe natural disaster with substantial social and economic consequences. Drought becomes most obvious when large-scale changes are observed; however, even moderate drought can have long-lasting impacts on the structure and function of forests and rangelands without these obvious large-scale changes. Large, stand-level impacts of drought are already underway in the West, but all U.S. forests are vulnerable to drought. Drought-associated forest disturbances are expected to increase with climatic change. Management actions can either mitigate or exacerbate the effects of drought. A first principal for increasing resilience and adaptation is to avoid management actions that exacerbate the effects of current or future drought. Options to mitigate drought include altering structural or functional components of vegetation, minimizing drought-mediated disturbance such as wildfire or insect outbreaks, and managing for reliable flow of water.
Download or read book Forest Giants of the Pacific Coast written by Robert Van Pelt and published by Global Forest Press. This book was released on 2001 with total page 228 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Invasive Species in Forests and Rangelands of the United States written by Therese M. Poland and published by Springer Nature. This book was released on 2021-02-01 with total page 455 pages. Available in PDF, EPUB and Kindle. Book excerpt: This open access book describes the serious threat of invasive species to native ecosystems. Invasive species have caused and will continue to cause enormous ecological and economic damage with ever increasing world trade. This multi-disciplinary book, written by over 100 national experts, presents the latest research on a wide range of natural science and social science fields that explore the ecology, impacts, and practical tools for management of invasive species. It covers species of all taxonomic groups from insects and pathogens, to plants, vertebrates, and aquatic organisms that impact a diversity of habitats in forests, rangelands and grasslands of the United States. It is well-illustrated, provides summaries of the most important invasive species and issues impacting all regions of the country, and includes a comprehensive primary reference list for each topic. This scientific synthesis provides the cultural, economic, scientific and social context for addressing environmental challenges posed by invasive species and will be a valuable resource for scholars, policy makers, natural resource managers and practitioners.
Download or read book Index to Theses with Abstracts Accepted for Higher Degrees by the Universities of Great Britain and Ireland and the Council for National Academic Awards written by and published by . This book was released on 2008 with total page 650 pages. Available in PDF, EPUB and Kindle. Book excerpt: Theses on any subject submitted by the academic libraries in the UK and Ireland.
Download or read book Tree Rings written by Fritz Hans Schweingruber and published by Springer Science & Business Media. This book was released on 2012-12-06 with total page 290 pages. Available in PDF, EPUB and Kindle. Book excerpt: At a meeting of dendrochronologists an American colleague described the effects of volcanic eruptions on annual ring formation in bristlecone pines. I knew very little about either volcanoes or American pines! At the same meeting European scientists spoke on the dendrochronological dating of lakeshore settlements and the effects of larch bud moth attack on trees in the Alps. It is possible that American participants were not in a position to fully appreciate these papers either. In other words, dendrochronology is an extremely interdisciplinary science; its facets range from modern statistics on wood anatomy to the history of art. It is difficult even for dendrochronol ogists to keep in touch with the whole spectrum, and even more difficult for the layman to obtain an overall view of the many methods and fields of application. In recent times specialisation has begun to hinder communication be tween the various sectors. Archaeologists, for instance, set up their own dendrochronological laboratories and construct independent chronologies to serve their particular interests. The scientific institutions which previously carried out such work are now turning more and more to strongly statistically or biologically-oriented questions. The full wealth of information contained in tree rings, however, will be revealed only when dendrochronologists make a concerted effort to relate the findings of the different fields. In spite of inevitable specialisation, it is necessary that the expert concern himself with the work of his colleagues.
