Download or read book Forests under pressure The need for interdisciplinary approaches to address forest vulnerability to tree mortality in response to drought written by Angelo Rita and published by Frontiers Media SA. This book was released on 2023-03-14 with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Multiscale Approach to Assess Forest Vulnerability written by Giovanna Battipaglia and published by Frontiers Media SA. This book was released on 2020-07-14 with total page 240 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Detecting Drought induced Tree Mortality in Sierra Nevada Forests written by Sarah Ann Byer and published by . This book was released on 2017 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A five-year drought in California has led to a significant increase in tree mortality in the Sierra Nevada forests from 2012 to 2016. Landscape level monitoring of forest health and tree dieback is critical for vegetation and disaster management strategies. We examined the capability of multispectral imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) in detecting and explaining the impacts of the recent severe drought in Sierra Nevada forests. Remote sensing metrics were developed to represent baseline forest health conditions and drought stress using time series of MODIS vegetation indices (VIs) and a water index. We used Random Forest algorithms, trained with forest aerial detection surveys data, to detect tree mortality based on the remote sensing metrics and topographical variables. Map estimates of tree mortality demonstrated that our two-stage Random Forest models were capable of detecting the spatial patterns and severity of tree mortality, with an overall producer’s accuracy of 96.3% for the classification Random Forest (CRF) and a RMSE of 7.19 dead trees per acre for the regression Random Forest (RRF). The overall omission errors of the CRF ranged from 19% for the severe mortality class to 27% for the low mortality class. Interpretations of the models revealed that forests with higher productivity preceding the onset of drought were more vulnerable to drought stress and, consequently, more likely to express tree mortality. This method highlights the importance of incorporating baseline forest health data and measurements of drought stress in understanding forest response to severe drought.

Download or read book Studying Tree Responses to Extreme Events written by Achim Bräuning and published by Frontiers Media SA. This book was released on 2017-06-05 with total page 468 pages. Available in PDF, EPUB and Kindle. Book excerpt: Trees are among the longest-living organisms. They are sensitive to extreme climatic events and document the effects of environmental changes in form of structural modifications of their tissues. These modifications represent an integrated signal of complex biological responses enforced by the environment. For example, temporal change in stem increment integrates multiple information of tree performance, and wood anatomical traits may be altered by climatic extremes or environmental stress. Recent developments in preparative tools and computational image analysis enable to quantify changes in wood anatomical features, like vessel density or vessel size. Thus, impacts on their functioning can be related to climatic forcing factors. Similarly, new developments in monitoring (cambial) phenology and mechanistic modelling are enlightening the interrelationships between environmental factors, wood formation and tree performance and mortality. Quantitative wood anatomy is a reliable indicator of drought occurrence during the growing season, and therefore has been studied intensively in recent years. The variability in wood anatomy not only alters the biological and hydraulic functioning of a tree, but may also influence the technological properties of wood, with substantial impacts in forestry. On a larger scale, alterations of sapwood and phloem area and their ratios to other functional traits provide measures to detect changes in a tree’s life functions, and increasing risk of drought-induced mortality with possible impacts on hydrological processes and species composition of plant communities. Genetic variability within and across populations is assumed to be crucial for species survival in an unpredictable future world. The magnitude of genetic variation and heritability of adaptive traits might define the ability to adapt to climate change. Is there a relation between genetic variability and resilience to climate change? Is it possible to link genetic expression and climate change to obtain deeper knowledge of functional genetics? To derive precise estimates of genetic determinism it is important to define adaptive traits in wood properties and on a whole-tree scale. Understanding the mechanisms ruling these processes is fundamental to assess the impact of extreme climate events on forest ecosystems, and to provide realistic scenarios of tree responses to changing climates. Wood is also a major carbon sink with a long-term residence, impacting the global carbon cycle. How well do we understand the link between wood growth dynamics, wood carbon allocation and the global carbon cycle? Papers contribution to this Research Topic will cover a wide range of ecosystems. However, special relevance will be given to Mediterranean-type areas. These involve coastal regions of four continents, making Mediterranean-type ecosystems extremely interesting for investigating the potential impacts of global change on growth and for studying responses of woody plants under extreme environmental conditions. For example, the ongoing trend towards warmer temperatures and reduced precipitation can increase the susceptibility to fire and pests. The EU-funded COST Action STREeSS (Studying Tree Responses to extreme Events: a SynthesiS) addresses such crucial tree biological and forest ecological issues by providing a collection of important methodological and scientific insights, about the current state of knowledge, and by opinions for future research needs.

Download or read book From the Cell to the Stand written by Jeffrey Lauder and published by . This book was released on 2020 with total page 334 pages. Available in PDF, EPUB and Kindle. Book excerpt: Climate change is expected to drive shifts in forest species distribution to track ideal climatic conditions. The relative capacity for a tree species to persist under climatic stress is dependent on life history traits, such as growth, survival, and reproduction. Trees that produce large amounts of seed may be better able to colonize newly suitable habitats, while those that survive stress at current locations may persist longer than nearby competitors. These traits each represent distinct resource sinks, however. What remains unknown is how physiological modification in response to drought influences both survival and reproductive capacity. I analyzed growth, tree ring anatomy, and reproductive capacity in Pinus ponderosa and P. jeffreyi in the Sierra Nevada mountains of California, where the unprecedented 2012-2016 drought led to large-scale forest mortality. I found that trees that died during drought unexpectedly exhibited anatomical traits thought to confer drought tolerance, such as thicker walls in water-conducting xylem cells. Under drought, trees close stomata (pores in their leaf surface involved in gas exchange) to limit water loss, but at the expense of carbon (C) uptake. This leads to a theoretical expectation of C depletion in drought-stressed trees, particularly during prolonged (i.e., multi-year) drought. While direct evidence of this "C-starvation" has not been recorded in nature, my results point to a potential mechanism of the impact of C depletion on mortality. The sampled trees also experienced a high level of bark beetle (Dendroctonus spp.) attack, which is typically defended against in trees via the production of C-rich resin and other chemical defenses. Drought appears to have weakened sampled trees, and excessive allocation of available resources to drought defense may have depleted reserves necessary for fending off beetle attack. To quantify potential tradeoffs between drought defense and reproduction, I developed a novel technique to measure total lignin (a C-expensive material involved in xylem cell wall thickening) in tree rings, and found that trees that died had higher lignin content than living trees. To further explore these patterns, I modeled likelihood of tree mortality as a function of tree ring width (growth), xylem anatomy, competition, and climate. I first compared multiple commonly used drought metrics with ring widths from>800 trees from across the Sierra Nevada and found that drought metric choice influences interpretation of drought impacts. I then showed that trees that grew not only thicker-walled xylem cells, but also more variable growth rings and variable cells between years were more likely to die. Trees that grew the same amount each year, or grew rings with relatively constant xylem cell diameters and wall thicknesses, were more likely to survive drought, counter to hypothesized tradeoffs between growth and reproduction during drought. Finally, cone counts of measured trees show that ring width (growth) was the primary determinant of reproductive capacity, with trees that grew more producing more cones. These results demonstrate that tree response to drought is a function of variation in xylem anatomy and ring width, with the mechanism of mortality being associated with C depletion. Trees that are less responsive to climate and maintain fairly constant growth appear to be most likely to survive prolonged drought, and trees that grow large rings (with low variance between years) are more likely to reproduce. These results improve our understanding of whole-forest response to future climate change by demonstrating the importance of both cellular scale (xylem anatomy) and forest-scale (drought metrics and competition) variation in influencing drought-induced forest mortality

Download or read book Forest Health Under Climate Change Effects on Tree Resilience and Pest and Pathogen Dynamics written by Riikka Linnakoski and published by Frontiers Media SA. This book was released on 2020-01-10 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Vegetation Dynamics written by Derek Eamus and published by Cambridge University Press. This book was released on 2016-03-31 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Understanding ecosystem structure and function requires familiarity with the techniques, knowledge and concepts of the three disciplines of plant physiology, remote sensing and modelling. This is the first textbook to provide the fundamentals of these three domains in a single volume. It then applies cross-disciplinary insights to multiple case studies in vegetation and landscape science. A key feature of these case studies is an examination of relationships among climate, vegetation structure and vegetation function, to address fundamental research questions. This book is for advanced students and researchers who need to understand and apply knowledge from the disciplines of plant physiology, remote sensing and modelling. It allows readers to integrate and synthesise knowledge to produce a holistic understanding of the structure, function and behaviour of forests, woodlands and grasslands.

Download or read book A review of existing approaches and methods to assess climate change vulnerability of forests and forest dependent people written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2018-11-29 with total page 84 pages. Available in PDF, EPUB and Kindle. Book excerpt: Until recently, considerably more attention was paid to using forests to mitigate climate change, through the absorption of carbon dioxide (CO2) from the atmosphere, than there was on considering the need to adapt forests to avoid the worst effects that climate change could have on them. The switch from a mitigation-heavy approach to one that considers adaptation in a more balanced manner underscores the need to have approaches to assess the vulnerability of forests to climate change. One reason for this more balanced focus may be due to the realization by the broader public, governmental organizations and the forest science community that the climate change that has already occurred is permanent in human terms, because it takes centuries for much of the CO2 emitted from fossil fuel sources to be removed from the atmosphere. There are already substantial impacts that are being seen in the world’s forests. These impacts are certain to continue increasing until CO2 emissions drop to lower levels. For that reason, adaptation of the world’s forests requires attention. The approaches to assessing vulnerability can be categorized according to the focus they each provide. Contextual vulnerability addresses current issues of climate and is usually evaluated using participatory techniques with people who live in, or work with, forests. Outcome vulnerability looks at the biophysical vulnerability of forests; it is often used to assess the cause-and-effect of climate change on a biological system. Vulnerability assessments can be highly technical and quantitative, using advanced computer programs and geographic information systems, or they can be based on social science approaches to obtaining qualitative information from people.

Download or read book Adaptation of Trees to Climate Change Mechanisms Behind Physiological and Ecological Resilience and Vulnerability written by Andrea Ghirardo and published by Frontiers Media SA. This book was released on 2022-02-16 with total page 136 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 Climate Change and United States Forests written by Peterson David L. and published by Springer. This book was released on 2016-09-17 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: This volume offers a scientific assessment of the effects of climatic variability and change on forest resources in the United States. Derived from a report that provides technical input to the 2013 U.S. Global Change Research Program National Climate Assessment, the book serves as a framework for managing U.S. forest resources in the context of climate change. The authors focus on topics having the greatest potential to alter the structure and function of forest ecosystems, and therefore ecosystem services, by the end of the 21st century. Part I provides an environmental context for assessing the effects of climate change on forest resources, summarizing changes in environmental stressors, followed by state-of-science projections for future climatic conditions relevant to forest ecosystems. Part II offers a wide-ranging assessment of vulnerability of forest ecosystems and ecosystem services to climate change. The authors anticipate that altered disturbance regimes and stressors will have the biggest effects on forest ecosystems, causing long-term changes in forest conditions. Part III outlines responses to climate change, summarizing current status and trends in forest carbon, effects of carbon management, and carbon mitigation strategies. Adaptation strategies and a proposed framework for risk assessment, including case studies, provide a structured approach for projecting and responding to future changes in resource conditions and ecosystem services. Part IV describes how sustainable forest management, which guides activities on most public and private lands in the United States, can provide an overarching structure for mitigating and adapting to climate change.

Download or read book Climate change for forest policy makers written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2019-02-18 with total page 73 pages. Available in PDF, EPUB and Kindle. Book excerpt: The critical role of forests in climate change mitigation and adaptation is now widely recognized. Forests contribute significantly to climate change mitigation through their carbon sink and carbon storage functions. They play an essential role in reducing vulnerabilities and enhancing adaptation of people and ecosystems to climate change and climate variability, the negative impacts of which are becoming increasingly evident in many parts of the world. In many countries climate change issues have not been fully addressed in national forest policies, forestry mitigation and adaptation needs at national level have not been thoroughly considered in national climate change strategies, and cross-sectoral dimensions of climate change impacts and response measures have not been fully appreciated. This publication seeks to provide a practical approach to the process of integrating climate change into national forest programmes. The aim is to assist senior officials in government administrations and the representatives of other stakeholders, including civil society organizations and the private sector, prepare the forest sector for the challenges and opportunities posed by climate change. This document complements a set of guidelines prepared by FAO in 2013 to support forest managers incorporate climate change considerations into forest management plans and practices.

Download or read book Physiological Responses to Abiotic and Biotic Stress in Forest Trees written by Heinz Rennenberg and published by MDPI. This book was released on 2019-10-01 with total page 294 pages. Available in PDF, EPUB and Kindle. Book excerpt: As sessile organisms, plants have to cope with a multitude of natural and anthropogenic forms of stress in their environment. Due to their longevity, this is of particular significance for trees. As a consequence, trees develop an orchestra of resilience and resistance mechanisms to biotic and abiotic stresses in order to support their growth and development in a constantly changing atmospheric and pedospheric environment. The objective of this Special Issue of Forests is to summarize state-of-art knowledge and report the current progress on the processes that determine the resilience and resistance of trees from different zonobiomes as well as all forms of biotic and abiotic stress from the molecular to the whole tree level.

Download or read book A First Assessment of the Impact of the Extreme 2018 Drought on Central European Forests written by Bernhard Schuldt and published by . This book was released on 2020 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Abstract: In 2018, Central Europe experienced one of the most severe and long-lasting summer drought and heat wave ever recorded. Before 2018, the 2003 millennial drought was often invoked as the example of a "hotter drought", and was classified as the most severe event in Europe for the last 500 years. First insights now confirm that the 2018 drought event was climatically more extreme and had a greater impact on forest ecosystems of Austria, Germany and Switzerland than the 2003 drought. Across this region, mean growing season air temperature from April to October was more than 3.3°C above the long-term average, and 1.2°C warmer than in 2003. Here, we present a first impact assessment of the severe 2018 summer drought and heatwave on Central European forests. In response to the 2018 event, most ecologically and economically important tree species in temperate forests of Austria, Germany and Switzerland showed severe signs of drought stress. These symptoms included exceptionally low foliar water potentials crossing the threshold for xylem hydraulic failure in many species and observations of widespread leaf discoloration and premature leaf shedding. As a result of the extreme drought stress, the 2018 event caused unprecedented drought-induced tree mortality in many species throughout the region. Moreover, unexpectedly strong drought-legacy effects were detected in 2019. This implies that the physiological recovery of trees was impaired after the 2018 drought event, leaving them highly vulnerable to secondary drought impacts such as insect or fungal pathogen attacks. As a consequence, mortality of trees triggered by the 2018 events is likely to continue for several years. Our assessment indicates that many common temperate European forest tree species are more vulnerable to extreme summer drought and heat waves than previously thought. As drought and heat events are likely to occur more frequently with the progression of climate change, temperate European forests might approach the point for a substantial ecological and economic transition. Our assessment also highlights the urgent need for a pan-European ground-based monitoring network suited to track individual tree mortality, supported by remote sensing products with high spatial and temporal resolution to track, analyse and forecast these transitions

Download or read book Impacts of Climate Change on Tree Physiology and Responses of Forest Ecosystems written by Mariangela Fotelli and published by . This book was released on 2021-12-27 with total page 172 pages. Available in PDF, EPUB and Kindle. Book excerpt: Extreme climatic events, such as intense and prolonged droughts and heat waves, are occurring with increasing frequency and with pronounced impacts on forests. Forest trees, as long-lived organisms, need to develop adaptation mechanisms to successfully respond to such climatic extremes. Whether physiological adaptations on the tree level result in ecophysiological responses that ensure plasticity of forest ecosystems to climate change is currently in the core forest research. Within this Special Issue, forest species' responses to climatic variability were reported from diverse climatic zones and ecosystem types: from near-desert mountains in western USA to tropical forests in central America and Asia, and from Mediterranean ecosystems to temperate European forests. The clear effects of constraints related to climate change were evidenced on the tree level, such as in differentiated gene expression, metabolite abundance, sap flow rates, photosynthetic performance, seed germination, survival and growth, while on the ecosystem level, tree line shifts, temporal shifts in allocation of resources and species shifts were identified. Experimental schemes such as common gardens and provenance trails also provided long-term indications on the tolerance of forest species against drought and warming and serve to evaluate their performance under the predicted climate in near future. These findings enhance our knowledge on the potential resilience of forest species and ecosystems to climate change and provide an updated basis for continuing research on this topic.

Download or read book Climate change vulnerability assessment of forests and forest dependent people written by Food and Agriculture Organization of the United Nations and published by Food & Agriculture Org.. This book was released on 2019-11-29 with total page 101 pages. Available in PDF, EPUB and Kindle. Book excerpt: Negative impacts of climate change on forests threaten the delivery of crucial wood and non-wood goods and environmental services on which an estimated 1.6 billion people fully or partly depend. Assessment of the vulnerability of forests and forest-dependent people to climate change is a necessary first step for identifying the risks and the most vulnerable areas and people, and for developing measures for adaptation and targeting them for specific contexts. This publication provides practical technical guidance for forest vulnerability assessment in the context of climate change. It describes the elements that should be considered for different time horizons and outlines a structured approach for conducting these assessments. The framework will guide practitioners in conducting a step-by-step analysis and will facilitate the choice and use of appropriate tools and methods. Background information is provided separately in text boxes, to assist readers with differing amounts of experience in forestry, climate change and assessment practices. The publication will provide useful support to any vulnerability assessment with a forest- and tree-related component.