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Globally, animals that are range-restricted are frequently becoming species of conservation concern, in part due to competitive exclusion by phylogenetically and ecologically similar species that are more tolerant of human disturbance. However, climate and land use changes to natural landscapes can create pockets of refugia for range-restricted species. Western gray squirrels (Sciurus griseus) are native to the west coast of North America, principally California and western Oregon. Over the past several decades, Western Gray Squirrel populations have declined in human-dominated areas, with increased competition from introduced congeneric species native to eastern North America cited as a primary driver. Despite declines in their established range west of the Pacific Crest in western North America, western gray squirrels are extending their range into the Great Basin, where they were not historically found. Using a network of remote camera traps deployed across the Sierra Nevada–Great Basin ecotone in northwestern Nevada, we detected western gray squirrels across 16 of 100 camera-trapping sites. The majority of detections were located in piñon–juniper woodland, a land cover type not previously occupied by this species. Occupancy modeling revealed that western gray squirrels were equally likely to occur in piñon–juniper woodland compared to mature pine forest that they occupy elsewhere in their range. A species distribution model parameterized with historical gray squirrel observations (pre-1950), indicated increased climatic suitability for the species on the eastern side of the Sierra Nevada in recent decades, which may have facilitated this range expansion. Our findings reveal the potential for species declining in their historical range to colonize novel habitats that become increasingly suitable as a result of human-driven changes to ecosystems. [ABSTRACT FROM AUTHOR]

Forest discourses help identify forest-related issues. They aim to aid policy and decision-makers in understanding forest-related challenges and opportunities better so that they may initiate possible strategies and tactics to tackle them. Ideally, information requirements for the forest discourses would be translated into measurable variables, being the basis for collecting, analysing, and reporting data and information. Our study examined the connection between major international forest reporting processes and forest discourses. We analysed summaries and key findings for policy makers of five recent major forest reports. We compared their focus with forest discourses on climate change, forest conservation, deforestation, forest decline, illegal logging, industrial forestry/bioeconomy, traditional knowledge, woody biomass production, and innovative wood-based biofuels. The paper explores how the forest discourses are reflected in the surveyed documents and closely examines the specific focus areas in the summaries for policy makers. The results show that most forest discourses are generally well-represented, albeit with different foci. The discourse on illegal logging could not be identified in any investigated documents, even though it remains a significant concern for international forest policy. Keywords related to traditional knowledge and woody biomass production could not be found in two of the analysed findings. All analysed summaries and key findings mention issues related to the climate change discourse topic. However, they lack information on emissions from deforestation, carbon dioxide emissions and carbon budgets, which are high in political discussions. The paper highlights how discourse issues have gained in complexity both topic-wise and regarding the reporting obligations, as policy and decisionmakers require more timely and comprehensive information about the status' and trends of forests. [ABSTRACT FROM AUTHOR]

(1) Background--Ecological industrialization takes ecological resources as the main research subject and realizes the economic value of ecological products and services by means of socialized production and market-oriented operation. (2) Methods--The weights of each index in the evaluation index system of ecological industrialization development level were determined according to entropy weight method, and the development level of ecological industrialization was measured by entropy weight TOP SIS model. (3) Results--First, the overall development level of ecological industrialization of the state-owned forest areas in Heilongjiang Province was low from 2001 to 2008, and the development index of other system levels was low except for the high development index of ecological environment quality. Due to the implementation of a series of ecological projects, the development index of ecological industrialization from 2009 to 2018 began to improve, and the development index of the four system levels also began to increase. Affected by the system transformation of Yichun Forest Industry Group and the COVID-19 pandemic, the development index of ecological industrialization from 2019 to 2021 began to decline. In addition to the continuous increase in the ecological environment quality level, the development index of the other three system levels declined. Second, the obstacle degree of each system level of ecological industrialization of the state-owned forest areas in Heilongjiang Province showed a trend of fluctuation decline from 2001 to 2018. Except for ecological environment quality level, the obstacle degree of the other system levels increased from 2019 to 2021. There were 17 obstacle factors affecting the development level of ecological industrialization, among which the average obstacle degree of forest resource index, pollution management index, industrial structure index and output value of pillar industry was the highest. (4) Conclusions and Discussions--First, the development level of ecological industrialization of the state-owned forest areas in Heilongjiang Province showed a fluctuating upward trend from 2001 to 2021, and the development level of ecological industrialization was constantly improving. Second, the change trend of the development level of the system level of ecological industrialization was different. The development level of the ecological environment quality continued to rise, while the development level of the other three system levels fluctuated first and then continued to decline. Third, the change of system level obstacle degree affecting the development of ecological industrialization had phases. The obstacle degree of ecological environment quality was the largest from 2001 to 2018, and the pillar industry level became the new main obstacle factor from 2018 to 2021. Fourth, the distribution of indexes restricting the development of ecological industrialization of the state-owned forest areas in Heilongjiang province was uneven in each system level. Forest resources, pollution management, industrial structure and output value of pillar industries were the main obstacle factors. According to the above research conclusions, the following policy recommendations are put forward: First, give priority to protection and improve the quality of the ecological environment. Second, optimize the industrial layout and improve the regional economic level. Third, extend the industrial chain and improve the level of pillar industries. Fourth, expand financing channels and increase capital investment. [ABSTRACT FROM AUTHOR]

Rapid urbanization in Algeria is causing significant problems, such as the emergence of unplanned neighborhoods, and local authorities need to apply modern tools like geomatics to monitor and update spatial planning databases to support sustainable development. More to the point, these tools—geographic information systems (GIS) and remote sensing (RS) are of assistance to update the spatial planning and development database so as to support the decision-making. In fact, for understanding the purpose of the process of urban growth in the region of the interior high plateaus, we chose the city of Setif as it represents an urban and economic pole in the region. Besides, economic activities exacerbate the phenomenon of rapid and unplanned urban growth alongside the environmental impact thereof. In the light of the obtained results, there exists a significant increase in urban lands and a significant decline in forests and agricultural lands, as the urban area has tripled from 10.4% in 1985 to 20.3 in 2003 and to 29.7% in 2021. At the same time, the agricultural area has then shrunk from 76.4% in 1985 to 65.8 in 2003 and to 55.5% in 2021, while the forest areas have decreased from 5.04% in 1985 to 4.4 in 2003 and to 2.3% in 2021. [ABSTRACT FROM AUTHOR]

The impact of climate change on insect pests is an emerging topic in forestry and forest science. This study investigates the relationships between two broadleaved forest pests – spongy moth (Lymantria dispar L.) and brown-tail moth (Euproctis chrysorrhoea L.) – and oaks (Quercus sp.) as their hosts. Oak forests cover almost one-third of the total forest area of Serbia and are ecologicallyvery valuable, but at the same time vulnerable, as being affected in adverse ways by several primary pests and pathogens. Since 1862, Serbia experienced several extremely large outbreaks of spongy moth with more than a hundred thousand hectares completely defoliated each time, while brown-tail moth occurred periodically with a much lower spatial extent. The aim of this research was to investigate the effect of UV radiation (UVR) and air temperature on spongy moth and brown-tail moth in Serbian forests. We used simulations of the coupled regional climate model EBU-POM (Eta Belgrade University-Princeton Ocean Model) for the A1B scenario for the period 2001-2030 as main input and different statistical methods to explore relationships between observations of pest spread and climate change impacts. Our results suggest (i) increasing the areas affected by spongy moth due to its sensitivity on UVR in May, and (ii) altitudinal spreading of brown-tail moth population up to 800 – 1000 m. This research indicates that in situ forest observations in Serbia are not only affected by climate change, but also by the combined effect of climate on forest pests. For further research, we recommend exploring other forest stressors or dieback phenomena in European forests by applying the same or similar regional climate model dataset. [ABSTRACT FROM AUTHOR]

Over the last half-century, North American forest birds have experienced staggering declines, while at the same time, many metrics indicate that North American forest health has improved. While the United States has been recognised for global leadership in innovation and research in forestry, the negative impacts of high-severity harvesting methods and forest fragmentation are sometimes overlooked, and a dearth of research studies exist that assess the impacts of lower-severity forestry practices on birds. Globally, some regions are pursuing markedly different forestry practices, and one example is Europe's Close-To-Nature Forestry (CTNF) that protects forest canopies. Historically, CTNF methods have not been promoted to help avian abundance or diversity; however, forest bird populations in Europe have increased 7% over the last two decades, and we posit whether similar forest management approaches in the eastern USA could benefit North American birds. Therefore, we sought to 1) assess the effects of forest structural characteristics on avian species richness in a CTNFmanaged forest in the eastern USA; 2) compare our results to county-level eBird data to identify the challenges of assessing the impacts of forestry practices on birds at landscape scales; 3) highlight the ambiguities in current forest management guidelines for improving avian habitats in the USA and 4) suggest long-term direction for evaluating the impacts of alternative forest management practices on birds. Our case study provides preliminary evidence that CTNF-managed forests may support diverse birds of high conservation value that are normally drawn to different forest management extremes. We also provide recommendations for utilising eBird data to assess alternative forest management strategies at landscape scales and a synthesised look at the forest management guidelines provided by many of the major players in American ornithology. While there may be multiple reasons for forest bird declines noted in the past 50 years in North America, long-standing forest management practices and policies should not be overlooked. [ABSTRACT FROM AUTHOR]

In response to escalating worldwide groundwater dependence amid climate change, accurate estimation of sustainable groundwater yield becomes crucial. This study investigated the impact of groundwater abstraction on tree mortality in Namibia. We compared tree mortality around production boreholes with monitoring boreholes and we correlated groundwater decline rates with tree mortality, establishing a model from which we derived a groundwater decline rate range limit. Ana tree mortality was significantly higher (P = 0.01) around production boreholes (13.3%) than around monitoring boreholes (0%). In the dammed Swakop River, Ana tree mortality correlated with decline rates (r S = 0.64, P < 0.01). The study suggests that decline rates of above 0.2–0.23 cm day−1 may cause elevated mortality (3–7%) and should not be sustained for extended periods. Rates exceeding 0.5 cm day−1 should be avoided, while monitoring is recommended for rates between 0.23 and 0.5 cm day−1. Woodlands in rivers with altered flood frequencies may be more sensitive to groundwater abstraction than previously thought. The study's methods offer a universal framework for refining sustainable yield calculations worldwide. • Riparian trees are likely more sensitive to groundwater abstraction than expected. • Pumping rates should not exceed 0.23 cm day−1 to avoid excessive tree mortality. • Abstraction rates of 0.5 cm day−1 and above should be avoided altogether. • Regular tree health and groundwater monitoring are essential. • Our method modifies the sustainable yield to prevent human-induced tree mortality. [ABSTRACT FROM AUTHOR]

Although forest areas have been growing in Europe, some forest types have been declining regionally. Since the 1980 s, there have been reports of defoliation and mortality in evergreen oak woodlands of the Iberian Peninsula. However, long-term and large-scale trends of Iberian oak decline are still poorly understood. We quantified trends in canopy cover for cork oak (Quercus suber) and holm oak (Q. rotundifolia) woodlands in mainland Portugal for a 50 year period (1965 to 2015). We considered loss of canopy cover a proxy of forest degradation and asked how it changed over time, in association with human activity and climate. Between 1965 and 2015, both cork oak and holm oak canopy cover showed declining trends (57.9% and 71.1% of sampling points, respectively). Canopy cover dynamics, however, differed across time. Between 1965 and 1990, canopy cover gains (over 35% of sampling points) prevailed over losses (under 20%), with larger differences for cork oak than holm oak. Between 1990 and 2015, canopy cover losses (over 70% of sampling points) were much higher than gains (under 9%). Oak canopy cover decrease was associated with flatter areas (usually having more intensive land use) for both oak species, higher cattle numbers (holm oak only) and higher mean temperature (cork oak only). Contrastingly, loss of holm oak canopy cover seems to have occurred in less hot and dry regions that enable more intensive land uses. Active restoration is urgently needed to reverse the current decline in canopy cover in Mediterranean evergreen oak woodlands. [ABSTRACT FROM AUTHOR]

Human activities have drastically reshaped global forest ecosystems in recent decades. However, identifying the origins, magnitude, and primary effects of these actions, especially in East Asia (EA), with a long history of human activity, remains challenging. Crucially, unraveling the early anthropogenic impacts on forest ecosystems has substantial implications for characterizing the Anthropocene. In this study, we collated and synthesized Holocene arboreal pollen (AP) sequences from 61 EA lake basins, which demonstrated an overall expansion of forest vegetation during the early to middle Holocene, followed by a retreat from 5 cal. ka BP. The cooling and drying climate during the mid- and late Holocene proved inimical to forest proliferation across EA. Survival imperatives are likely to drive humans to adopt grazing and farming, causing a transformation from forest land to agro-pastoral land. This change further accelerated forest ecosystem degradation. By dividing EA into five subregions, we observed asynchronous declines in forest vegetation from 8 cal. ka BP to 3 cal. ka BP. This trend is primarily attributed to human impacts, given the pronounced coincidence between forest reduction and emergence and prosperity of Neolithic agriculture in each region. Significantly, the positive feedback loop between population growth and agricultural expansion can amplify human impacts. Coupled with climatic effects, these factors resulted in EA's forest vegetation plummeting to its lowest level since 10 cal. ka BP at 2.1 cal. ka BP. Furthermore, the anthropogenic influences on EA forest vegetation mirror land use, soil erosion, and vegetation variability observed globally in terms of timeline. These alterations are driven by human activities, almost coinciding with shifts in atmospheric greenhouse gas levels away from their natural trajectory. We, therefore, argue that the Anthropocene definition should consider the aggregate environmental impact of human activities over millennia, rather than restricting to the most recent centuries. [ABSTRACT FROM AUTHOR]

In global forest mapping, I forest i is usually defined in terms of tree cover, and this is a limitation because in fragmented and degraded forests ecosystem function and services are impaired and that makes them different from fully functional and ecologically valuable forests (Chazdon et al. [5]). However, the FAO forest resource assessment merges degraded forest stands with functional forest ecosystems, whereas degraded lands and soils should be mapped separately for evaluating sustainable development goals (SDG) (see SDG indicator 15.3.1 [United Nations [33]]). We believe the first fundamental step for robust monitoring of real forest is the production of a global map of intact forests (Potapov et al. [26]; Watson et al. [34]) and old-growth forest patches (Frelich [10]). This highlights the need to monitor forest intactness and to protect forest function because many forest ecosystems - such as tropical forests - are likely to approach a breaking point (Taubert et al. [32]). [Extracted from the article]

Forest regeneration and expansion are occurring in many countries, with 80 million ha established from 2000 to 2012 under the Bonn accord and 17.5 million ha established from 1990 to 2005 according to the Food and Agriculture Organisation. Multiple reviews have linked increasing forest cover with reduced river flow and potentially detrimental effects downstream. Previous reviews have investigated trends in river flow response over time, but the influence of forest age remains uncertain. Partial river flow recovery (towards non‐forested conditions) has been reported in decades following forest establishment, but the role of climate in driving these trends has not been explored. Here, we evaluate river flow trends in 43 studies following forest establishment, which provide sufficient information to distinguish the effects of ageing forests from variable climate. Our meta‐analysis supports previous findings showing that forestation reduces annual river flow (by 23% after 5 years and 38% after 25 years) with greater reductions in catchments with higher mean annual precipitation, larger increases in forest cover, and which were idle, rather than agricultural land, prior to forestation. The impact of forests on river flow is sensitive to annual precipitation and potential evapotranspiration, but responses are highly variable. Forests affect river flow less when annual precipitation is low, and sensitivity to precipitation decreases as catchment aridity increases. The majority of catchments demonstrated persistent river flow declines after forest establishment. However, nine catchments showed partial flow recovery after an initial decrease, with peak flow reductions at an average age of 15 and across a range of tree species. The mean rate of recovery was 34 mm/year over 5 years. Partial flow recovery with forest age cannot be commonly expected, however, and forestation programmes should take into account that changes to annual river flow are likely to persist for up to five decades. [ABSTRACT FROM AUTHOR]

Plantation silviculture is increasing globally and is particularly intensive in temperate coniferous forests, where densely planting trees requires practices common to non‐conifer systems that can alter forest floor microhabitat, and potentially threaten amphibian persistence. Most declining amphibian species depend on specific forest microhabitats as terrestrial refugia, but amphibian extirpation associated with tree harvest alone appears unlikely, suggesting that impacts of planting forests on groundcover might better predict recent declines in amphibian occupancy.We repeatedly sampled larval presence or absence of 10 amphibian species native to temperate coniferous forest in the Southeastern United States for one year at 62 isolated wetlands, located in either naturally regenerating or planted forest (plantation). We assessed three direct ways that planted forests might reduce amphibian breeding site occupancy by: (a) increasing conifer densities, (b) decreasing groundcover, and (c) an indirect pathway, whereby increased tree densities at plantations might reduce groundcover and thus amphibian site occupancy.After controlling for wetland traits and accounting for differences in detection, breeding site occupancy for 8/10 amphibian species was dependent upon whether forests were planted surrounding wetlands (within 300 m). Herbaceous groundcover, not canopy, most commonly influenced occupancy and increased occupancy for declining surface active or fossorial amphibians.Path analyses showed that, by directly and indirectly reducing groundcover (via conifer densities), plantations had significantly lower occupancy of two declining surface active or fossorial frog species, whereas two common aquatic frog species were tolerant to planting conifers. Among declining species, salamanders showed a greater reduction in occupancy than anurans, likely because of greater vulnerability to the drier forest floor conditions of plantation than naturally regenerating forests.Synthesis and applications. Direct negative impacts of coniferous plantation on amphibians can be addressed by limiting groundcover and soil impacts, including switching from high intensity practices, such as mechanical chopping vegetation or bedding soil, to lower intensity site preparation treatments that are less likely to significantly disturb groundcover. Indirect negative effects of dense canopy cover at planted forests could be lowered by periodically thinning canopies prior to final harvest, thus increasing intact forest groundcover and the conservation of both common and declining amphibians. [ABSTRACT FROM AUTHOR]

In trees, wood anatomy is a more precise and informative measure of hydraulic responses to drought than radial growth. Tree populations located near the equatorial-range edge of their distribution (rear edge) are used to monitor responses to changes in hydroclimate; however, few studies have assessed the wood anatomy of these populations. We measured tracheid lumen diameter (LD) and cell wall thickness (CWT) in a rear-edge Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) population. We also evaluated the formation of intra-annual density fluctuations (IADFs), characterized by earlywood (EW) tracheids with narrow lumens. We expected that EW LD would be particularly sensitive to hydroclimate variability. We found that EW LD was directly related to precipitation during the previous year's late winter and the current year's spring. Wet conditions were associated with wider EW tracheids and improved growth. These correlations peaked when considering cumulative precipitation from January to May. EW IADFs were formed in response to dry conditions during March and April, suggesting that dry spring conditions limit tracheid expansion. The described associations in a rear-edge Douglas-fir population confirm that wood anatomy is highly responsive to drought. We conclude that EW LD is a valuable proxy for hydroclimate reconstruction in Douglas-fir. [ABSTRACT FROM AUTHOR]

The aim of this study was to evaluate (1) effects of bark stripping and climatic factors on radial growth of Picea abies /L./ Karst., (2) production and structural differences between stands established on the forestland and abandoned farmland (afforested farmland–henceforth, farmland), and (3) interaction among the losses caused by ungulate damages, production, diversity, and soil types. Data acquired from four permanent research plots (PRPs) located on the forestland and eight PRPs on the farmland were used. A number of tree- and stand-level models, stand structural indices, tree-rings, and climate characteristics were analysed to evaluate the hypotheses. The results show significantly higher means of DBH, tree height and basal area on the forestland compared to those on the farmland. There was a larger mean standing stem volume on the forestland (466 m3 ha–1) compared to farmland (770 m3 ha–1). Significant difference was observed between the mean DBH and mean stem volume of healthy trees compared to those of the trees with substantial damage (girth damage >1/3 of stem circumference). A greater extent of the girth damage was found on 86% trees on the farmland, while 54% damage on the forestland. About 62% bark-strip damage was further deteriorated by rot infection on the farmland, while on the forestland such an infection was only for 39% trees. The precipitation significantly positively affected the radial growth of trees that were largely affected by ungulate damages on the farmland. [ABSTRACT FROM AUTHOR]

• Land cover dynamics in dry tropical environments are often overlooked. • Classification accuracy of 79–86% was attained using Landsat data. • Primary forest declined, while secondary forest increased. • Deforestation has continued to increase with low rates of recovery. • Forest connectivity declined by 22% between 1972 and 2016. Land cover dynamics in the tropical dry environments of sub-Saharan Africa are not well understood compared to humid environments, especially on a national scale. Previous studies describing land cover in the dry tropics are spatially or temporally constrained. This study presents the first long-term (1972–2016) nationwide land cover dynamics and forest connectivity analyses for Zambia. We employed 300 Landsat images and an object-based image analysis (OBIA) approach with the Random Forests (RF) classifier to map nine land covers at six time steps (1972, 1984, 1990, 2000, 2008 and 2016). Post-classification change detection was used to understand the dynamics, while landscape metrics were derived to assess the forest structural connectivity. Overall accuracies ranging from 79 to 86% were achieved. In 1972, 48% of Zambia was covered by primary forest and 16% was covered by secondary forest. By 2016, 62.74% of Zambia had undergone changes, with primary forest decreasing by 32% and secondary forest increasing by 23%. Our results showed that forests have been recovering by 0.03 to 1.3% yr−1 (53, 000–242, 000 ha yr-1); however, these rates are markedly lower than deforestation rates (- 0.54 to - 3.05% yr-1: 83, 000–453, 000 ha yr-1). Annual rates of change varied by land cover, with irrigated crops having the largest increase (+ 3.19 yr-1) and primary forest having the greatest decrease (-2.48% yr-1). Forest connectivity declined by 22%, with primary forest having the greatest decline, while the connectivity for secondary and plantation forest increased. We showed here that land cover in Zambia is highly dynamic with high rates of change, low forest recovery and decline in forest connectivity. These findings will aid in land use planning, reporting for the forthcoming 2020 Global Forest Resources Assessment, and carbon accounting, especially under the reduction in carbon emissions from deforestation and degradation programme (REDD+). [ABSTRACT FROM AUTHOR]

Forests are a major natural resource of the state of California, where over a third of the land is forested, and provide a wide range of environmental, economic, and social benefits. Over the past decade, unprecedented drought, insect outbreaks and wildfires have resulted in large-scale tree mortality that greatly affects the forest ecosystem and poses significant threat to human health and welfare and to the environment. Forest thinning and management is considered imperative to improve forest health and resilience. Forest resources including dead and dying trees as well as the residues produced from forest thinning and timber harvesting operations could potentially be used to a greater degree than at present to generate electricity and other renewable energy to meet the increasing demand for more sustainable supplies and mitigate the risk of wildfires. However, efforts to construct new electricity generation capacity in the state at any scale over the last several decades have faced both economic and environmental challenges. As needs for alternative management approaches have become clear, opportunities have emerged for new bioenergy projects. These projects need to be effectively planned and potential economic and environmental performance carefully evaluated. Toward this purpose, an integrated framework model for lifecycle and technoeconomic assessment was developed to quantify environmental and economic impacts, initially for generating electricity using forest resources and with associated web services developed for an online application (forestdss.ucdavis.edu) that allows potential users to quickly estimate the economic and environmental performance of a potential facility at specified locations. • Tree mortality, past fire suppression practices, and high fuel loadings threaten forests and human health and welfare. • Forest resources including dead and dying trees as well as residues can be used for greater renewable energy production. • Bioenergy projects need to be effectively planned and potential economic and environmental performance carefully evaluated. • An integrated spatial framework model was developed to aid in decision making related to new project investments. [ABSTRACT FROM AUTHOR]

Recent increases in the magnitude and occurrence of insect-induced tree mortality are disrupting evergreen forests globally. To resolve potentially conflicting ecosystem responses, we investigated whether surrounding trees exert compensatory effects on biogeochemical signatures following beetle infestation. To this end, plots were surveyed within a Colorado Rocky Mountain watershed that experienced beetle infestation almost a decade prior and contained a range of surrounding tree mortality (from 9 to 91% of standing trees). Near-surface soil horizons under plot-centered live (green) and beetle-killed (grey) lodgepole pines were sampled over two consecutive summers with variable moisture conditions. Results revealed that soil respiration was 18–28% lower beneath beetle-infested trees and correlated to elevated dissolved organic carbon aromaticity. While certain edaphic parameters including pH and water content were elevated below grey compared to green trees regardless of the mortality extent within plots, other biogeochemical responses required a higher severity of surrounding mortality to overcome compensatory effects of neighboring live trees. For instance, C:N ratios under grey trees declined with increased severity of surrounding tree mortality, and the proportion of ammonium displayed a threshold effect with pronounced increases after surrounding tree mortality exceeded ∼40%. Overall, the biogeochemical response to tree death was most prominent in the mineral soil horizon where tree mortality had the largest affect on carbon recalcitrance and the enrichment of nitrogen species. These results can aid in determining when and where nutrient cycles and biogeochemical feedbacks to the atmosphere and hydrosphere will be observed in association with this type of ecological disturbance. [ABSTRACT FROM AUTHOR]

We synthesize insights from current understanding of drought impacts at stand-to-biogeographic scales, including management options, and we identify challenges to be addressed with new research. Large stand-level shifts underway in western forests already are showing the importance of interactions involving drought, insects, and fire. Diebacks, changes in composition and structure, and shifting range limits are widely observed. In the eastern US, the effects of increasing drought are becoming better understood at the level of individual trees, but this knowledge cannot yet be confidently translated to predictions of changing structure and diversity of forest stands. While eastern forests have not experienced the types of changes seen in western forests in recent decades, they too are vulnerable to drought and could experience significant changes with increased severity, frequency, or duration in drought. Throughout the continental United States, the combination of projected large climate-induced shifts in suitable habitat from modeling studies and limited potential for the rapid migration of tree populations suggests that changing tree and forest biogeography could substantially lag habitat shifts already underway. Forest management practices can partially ameliorate drought impacts through reductions in stand density, selection of drought-tolerant species and genotypes, artificial regeneration, and the development of multistructured stands. However, silvicultural treatments also could exacerbate drought impacts unless implemented with careful attention to site and stand characteristics. Gaps in our understanding should motivate new research on the effects of interactions involving climate and other species at the stand scale and how interactions and multiple responses are represented in models. This assessment indicates that, without a stronger empirical basis for drought impacts at the stand scale, more complex models may provide limited guidance. [ABSTRACT FROM AUTHOR]

Individual actions to avoid, benefit from, or cope with climate change impacts partly shape adaptation; much research on adaptation has focused at the systems level, overlooking drivers of individual responses. Theoretical frameworks and empirical studies of environmental behavior identify a complex web of cognitive, affective, and evaluative factors that motivate stewardship. We explore the relationship between knowledge of, and adaptation to, widespread, climate-induced tree mortality to understand the cognitive (i.e., knowledge and learning), affective (i.e., attitudes and place attachment), and evaluative (i.e., use values) factors that influence how individuals respond to climate-change impacts. From 43 semistructured interviews with forest managers and users in a temperate forest, we identified distinct responses to local, climate-induced environmental changes that we then categorized as either behavioral or psychological adaptations. Interviewees developed a depth of knowledge about the dieback through a combination of direct, place-based experiences and indirect, mediated learning through social interactions. Knowing that the dieback was associated with climate change led to different adaptive responses among the interviewees, although knowledge alone did not explain this variation. Forest users reported psychological adaptations to process negative attitudes; these adaptations were spurred by knowledge of the causes, losses of intangible values, and impacts to a species to which they held attachment. Behavioral adaptations exclusive to a high level of knowledge included actions such as using the forests to educate others or changing transportation behaviors to reduce personal energy consumption. Managers integrated awareness of the dieback and its dynamics across spatial scales into current management objectives. Our findings suggest that adaptive management may occur from the bottom up, as individual managers implement new practices in advance of policies. As knowledge of climate-change impacts in local environments increases, resource users may benefit from programs and educational interventions that facilitate coping strategies. [ABSTRACT FROM AUTHOR]

Humans rely on healthy forests to supply energy, building materials, and food and to provide services such as storing carbon, hosting biodiversity, and regulating climate. Defining forest health integrates utilitarian and ecosystem measures of forest condition and function, implemented across a range of spatial scales. Although native forests are adapted to some level of disturbance, all forests now face novel stresses in the form of climate change, air pollution, and invasive pests. Detecting how intensification of these stresses will affect the trajectory of forests is a major scientific challenge that requires developing systems to assess the health of global forests. It is particularly critical to identify thresholds for rapid forest decline, because it can take many decades for forests to restore the services that they provide. [ABSTRACT FROM AUTHOR]

Interactions between climate and land-use change may drive widespread degradation of Amazonian forests. High-intensity fires associated with extreme weather events could accelerate this degradation by abruptly increasing tree mortality, but this process remains poorly understood. Here we present, to our knowledge, the first field-based evidence of a tipping point in Amazon forests due to altered fire regimes. Based on results of a large-scale, long-term experiment with annual and triennial burn regimes (B1yr and B3yr, respectively) in the Amazon, we found abrupt increases in fire-induced tree mortality (226 and 462%) during a severe drought event, when fuel loads and air temperatures were substantially higher and relative humidity was lower than long-term averages. This threshold mortality response had a cascading effect, causing sharp declines in canopy cover (23 and 31%) and aboveground live biomass (12 and 30%) and favoring widespread invasion by flammable grasses across the forest edge area (80 and 63%), where fires were most intense (e.g., 220 and 820 kW·m-1). During the droughts of 2007 and 2010, regional forest fires burned 12 and 5% of southeastern Amazon forests, respectively, compared with <1% in nondrought years. These results show that a few extreme drought events, coupled with forest fragmentation and anthropogenic ignition sources, are already causing widespread fire-induced tree mortality and forest degradation across southeastern Amazon forests. Future projections of vegetation responses to climate change across drier portions of the Amazon require more than simulation of global climate forcing alone and must also include interactions of extreme weather events, fire, and land-use change. [ABSTRACT FROM AUTHOR]

Abstract: The retrieval of indicators of vegetation stress from remote sensing imagery is an important issue for the accurate assessment of forest decline. The Photochemical Reflectance Index (PRI) has been demonstrated as a physiological index sensitive to the epoxidation state of the xanthophyll cycle pigments and to photosynthetic efficiency, serving as a proxy for short-term changes in photosynthetic activity, stress condition, and pigment absorption, but highly affected by illumination conditions, viewing geometry and canopy structure. In this study, a diurnal airborne campaign was conducted over Pinus sylvestris and Pinus nigra forest areas with the Airborne Hyperspectral Scanner (AHS) to evaluate the effects of canopy structure on PRI when used as an indicator of stress in a conifer forest. The AHS airborne sensor was flown at two times (8:00GMT and 12:00GMT) over forest areas under varying field-measured stress levels, acquiring 2m spatial resolution imagery in 80 spectral bands in the 0.43–12.5μm spectral range. Five formulations of PRI (based on R531 as a xanthophyll-sensitive spectral band) were calculated using different reference wavelengths, such as PRI570 (reference band RREF =R570), and the PRI modifications PRIm1 (RREF =R512), PRIm2 (RREF =R600), PRIm3 (RREF =R670), and PRIm4 (RREF =R570, R670), along with other structural indices such as NDVI, SR, OSAVI, MSAVI and MTVI2. In addition, thermal bands were used for the retrieval of the land surface temperature. A radiative transfer modeling method was conducted using the LIBERTY and INFORM models to assess the structural effects on the PRI formulations proposed, studying the sensitivity of PRIm indices to detect stress levels while minimizing the effects caused by the conifer architecture. The PRI indices were related to stomatal conductance, xanthophyll epoxidation state (EPS) and crown temperature. The modeling analysis showed that the coefficient of variation (CV) for PRI was 50%, whereas the CV for PRIm1 (band R512 as a reference) was only 20%. Simulation and experimental results demonstrated that PRIm1 (RREF =R512) was less sensitive than PRI (RREF =R570) to changes in Leaf Area Index (LAI) and tree densities. PRI512 was demonstrated to be sensitive to EPS at both leaf (r2 =0.59) and canopy level (r2 =0.40), yielding superior performance than PRI570 (r2 =0.21) at the canopy level. In addition, PRI512 was significantly related to water stress indicators such as stomatal conductance (Gs; r2 =0.45) and water potential (Ψ; r2 =0.48), yielding better results than PRI570 (Gs, r2 =0.21; Ψ, r2 =0.21) due to the structural effects found on the PRI570 index at the canopy level. [Copyright &y& Elsevier]

Forest dieback is a worldwide problem that is likely to increase with climate change and increasing human demands for resources. Eucalyptus camaldulensis forests are an acute example of forest dieback, with 70% of the Victorian Murray River floodplain in some state of dieback. If we are to halt dieback in these floodplain forests, we need to understand what makes stands susceptible to dieback. Forest diebacks are often related to stand structure, with dieback more severe in senescent or high-density stands. We determined whether certain stand structures make these forests more susceptible to dieback. We undertook an extensive survey of 176 stands across 100 000 ha of forest, covering the range of stand condition on this floodplain. Large and small trees (20-, 40-, 80- and 120-cm diameter) showed a similar reduction in the probability of being alive with decreasing stand condition. A slight improvement in stand condition was found at higher densities and basal areas, which may reflect the higher productivity or younger age of these stands. Stand condition was moderately, positively correlated with longitude, with stand condition being higher in the east of the Murray River floodplain where flooding frequencies are currently higher. This suggests that dieback of these floodplain forests would be more effectively mitigated by increased water availability through flooding than by altering stand structure. [ABSTRACT FROM AUTHOR]

Abstract: Few data are available on the relative importance of different site-specific factors (e.g. topographic parameters, vegetation, soil-specific factors) for soil organic carbon (SOC) distribution in northern forests. Moreover, an increasing frequency of large-scale forest dieback in these forests may change the SOC stock and its spatial distribution. Univariate and multivariate geostatistics were applied to elucidate the spatial variability of SOC stocks of different landscape units under a high-elevation Norway spruce (Picea abies L.) forest in central Europe and its relation to topographic parameters, soil-specific factors, and the impact of recent and past stand composition. We studied four high-elevation sites: Three are stocked with unmanaged Norway spruce (P. abies L.) forest, but differ in their positions on hillslope, topographic parameters, and soil type. At an adjacent site the spruce forest had been destroyed by bark-beetle (Ips typographus) infestation 25 years ago (dieback site). The fallen logs remained at the site and the site was not reforested. Soil samples were taken from the forest floor and the mineral soil. Fine root biomass and SOC stocks were significantly negatively spatially correlated at the spruce sites, but spatially independent at the dieback site due to the homogeneous distribution of grass roots at this site. For none of the sites with healthy Norway spruce forest, forest floor thickness or the magnitude of the SOC stocks at a given sampling point was related to its distance to the nearest tree. This is attributed to an overwhelming impact of small-scale topography (≤5 m) on the SOC stock distribution. In contrast, at the dieback site the SOC stocks in the forest floor and the topsoil horizon showed a significant negative spatial correlation with the distance to the nearest fallen log. The spatial variability of the SOC stocks in the mineral soil increased with increasing stone content and curvature heterogeneity. Clay content and SOC stocks were spatially positively correlated at each site, demonstrating the importance of soil texture on SOC distribution. Our results indicate that topographic parameters dominate the distribution of topsoil and subsoil SOC stocks at stand scale at the investigated sites. In contrast, tree distribution is only of minor importance at these sites with a distinctive patchy topographic structure. Particularly in sloped terrain, fallen logs have the potential to change the spatial distribution of SOC stocks in the forest floor, but also in the mineral topsoil considerably, and within a period of a few decades. [Copyright &y& Elsevier]

Abstract: Annual forest cover loss indicator maps for the humid tropics from 2000 to 2005 derived from time-series 500 m data from the MODerate Resolution Imaging Spectroradiometer (MODIS) were compared with annual deforestation data from the PRODES (Amazon Deforestation Monitoring Project) data set produced by the Brazilian National Institute for Space Research (INPE). The annual PRODES data were used to calibrate the MODIS annual change indicator data in estimating forest loss for Brazil. Results indicate that MODIS data may be useful in providing a first estimate of national forest cover change on an annual basis for Brazil. When directly compared with PRODES change at the MODIS grid scale for all years of the analysis, MODIS change indicator maps accounted for 75% of the PRODES change. This ratio was used to scale the MODIS change indicators to the PRODES area estimates. A sliding threshold of percent PRODES forest and 2000 to 2005 deforestation classes per MODIS grid cell was used to match the scaled MODIS to the official PRODES change estimates, and then to differentiate MODIS change within various sub-areas of the PRODES analysis. Results indicate significant change outside of the PRODES-defined intact forest class. Total scaled MODIS change area within the PRODES historical deforestation and forest area of study is 120% of the official PRODES estimate. Results emphasize the importance of synoptic monitoring of all forest change dynamics, including the cover dynamics of intact humid forest, regrowth, plantations, and cerrado tree cover assemblages. Results also indicate that operational MODIS-only forest cover loss algorithms may be useful in providing near-real time areal estimates of annual change within the Amazon Basin. [Copyright &y& Elsevier]

Forest decline in Ethiopia is highlighted by several authors but there is no consensus on its causes and consequences. The objective of this study is to investigate, from sociopolitical and geographical perspectives, the linkage between the trend of forest decline and changes in the social, economic, and political pattern in the Awassa watershed over a 100-year perspective. Field observations, satellite image and map analyses, interviews, and literature studies were employed, and natural indicators were analyzed. The findings indicate that the forest area declined from about 40% at the turn of the 19th century to less than 3% in the year 2000. Forest decline in the study area during the elected time period is the result of the combination of biophysical and social conditions. Important causes are geographic properties, sociopolitical changes, population growth, unstable land tenure principles, agricultural development, and the improvement of transport capacity. The main conclusions are as follows: Already in the early 20th century forest decline was in progress and forests were attributed an insignificant economic classification. Large areas of forest were cut down during periods of political transition when as a result of the political vacuum, interest in the protection of resources including forests was lacking. Long-term planning efforts to manage forests were obstructed by uncertainty resulting from land tenure principle change during each political period. The sparse area of forest land that remains is becoming increasingly attractive as potential land for arable agriculture because of improved road access between the study area and distant markets. [ABSTRACT FROM AUTHOR]

Vegetation and quantitative climate reconstructions from a northwestern France shelf core (VK03-58Bis) show orbital and suborbital climate variability for the last 8850 years in this region. A long-term cooling trend in summer temperatures, marked by gradual temperate and humid forest decline, parallels cooling in Greenland and the decrease of mid-latitude summer insolation reduction until at least 2000 cal. yr BP. At the long-term scale, the lowering in seasonal contrast revealed by vegetation changes follows the increase of precession. Corylus woodlands spread at the expense of deciduous Quercus forest, between 8740 and 8390 cal. yr BP, linked with the high seasonality conditions that, counterbalancing the long-term astronomical forcing trend, were amplified by the north Atlantic high-latitudes winter sea-ice expansion. High seasonality conditions resulted from the Agassiz and Ojibway final outburst episodes and consequent gradual reduction of the Meridional Overturning Circulation (MOC). Between 8390-8060 cal. yr BP, a sudden Corylus woodland decline marks the 8.2 kyr cold event in northwestern France probably triggered by the severe MOC reduction leading to the additional drop in winter temperature over Europe and Greenland. Nonetheless, seasonality remains high during this interval. The high seasonality conditions detected in 'VK03-58Bis' between 8740 and 8060 cal. yr BP reflects the multicentennial-scale climate cooling 8.6-8.0 kyr episode of the North Atlantic. Following the Agassiz and Ojibway final outburst episodes, climate became more stable. However, millennialscale climate cooling episodes are recorded in 'VK03-Bis' and are characterized by weak winter cooling and increases in precipitation. Furthermore, dinocyst analysis and benthic gastropod Turritella communis occurrences indicate regional changes such as the southward migration of the Boreal biogeographical zone between 8740 and 8480 cal. yr BP and the subsequent opening of the English Channel at around 8480-8390 cal. yr BP. [ABSTRACT FROM AUTHOR]

The study provides an example of mapping tropical forest cover from SPOT-Vegetation satellite images of coarse spatial resolution (1 km) for the subregion of insular Southeast Asia. A satellite image mosaic has been generated from satellite images acquired for the period 1998 to 2000. Forest cover has been mapped by unsupervised digital classification. The mapping result has then been compared to selected forest maps from the subregion, demonstrating the potential to provide basic information on forest area extent and distribution, but also on massive forest cover change in the subregional context. Forest area estimates derived from the map for the subregion have been found comparable to those compiled by FAO. The results indicate that many of the remaining tropical forests in Southeast Asia, rich in timber resources and biodiversity, may be lost in the near future if deforestation continues at present or previous rates. [ABSTRACT FROM AUTHOR]

Presents the first article in a series exploring the possible relationship between forest damage and acid rain in Europe. Measurement of forest decline; Methods of data synthesis; Findings on forest decline; The extent of decline.

Discusses the effects of air pollution, acid rain, nitrous oxide, and changes in the ozone level on the health of forests in industrial countries. How air pollution can cause tree mortality by toxification; Relationship between acid rain and forest dieback; Comparison of natural and nonnatural dieback; Consideration of the dieback of the balsam-fir in New England; How forests adapt to dieback in order to begin a recovery process.

Discusses how stress is the cause of change in the photosynthate allocation in trees which may cause them to die. Consideration of abnormalities in the resource allocation of trees; Seasonality of the production of shoots, stems, roots, and storage reserves; Requirements for photosynthesis by forest canopies; Impact of stress induced by drought; Probability of survival for trees under stress.

The Zagros forests in Western Iran are valuable ecosystems that have been seriously damaged by human interference (harvesting the wood and forest sub-products, converting the forests to the agricultural lands, and grazing) and natural events (drought events and fire). In this study, we generated accurate land cover (LC), and tree canopy cover percentage (TCC%) maps for the forests of Shirvan County, a part of Zagros forests in Western Iran using Sentinel-2, Google Earth, and field data for protective management. First, we assessed the accuracy of Google Earth data using 300 random field plots in 10 different land cover types. For land cover mapping, we evaluated the performance of four supervised classification algorithms (minimum distance (MD), Mahalanobis distance (MaD), neural network (NN), and support vector machine (SVM)). The accuracy of the land cover maps was assessed using a set of 150 stratified random plots in Google Earth. We mapped the forest canopy cover by using the normalized difference vegetation index (NDVI) map, and field plots. We calculated the Pearson correlation between the NDVI values and the TCC% (obtained from field plots). The linear regression between the NDVI values and the TCC% was used to obtain the predictive model of TCC% based on the NDVI. The results showed that Google Earth data yielded an overall accuracy of 94.4%. The SVM algorithm had the highest accuracy for the classification of Sentinel-2 data with an overall accuracy of 81.33% and a kappa index of 0.76. The results of the forest canopy cover analysis showed a Pearson correlation coefficient of 0.93 between the NDVI and TCC%, which is highly significant. The results also showed that the linear regression model is a good predictive model for TCC% estimation based on the NDVI (r2 = 0.864). The results can be used as a baseline for decision-makers to monitor land cover change in the region, whether produced by human activities or natural events and to establish measures for protective management of forests. [ABSTRACT FROM AUTHOR]

Land cover changes, especially excessive economic forest plantations, have significantly threatened the ecological security of West Dongting Lake wetland in China. This work aimed to investigate the spatiotemporal dynamics of forests in the West Dongting Lake region from 2000 to 2018 using a reconstructed monthly Landsat NDVI time series. The multi-type forest changes, including conversion from forest to another land cover category, conversion from another land cover category to forest, and conversion from forest to forest (such as flooding and replantation post-deforestation), and land cover categories before and after change were effectively detected by integrating Breaks For Additive Seasonal and Trend (BFAST) and random forest algorithms with the monthly NDVI time series, with an overall accuracy of 87.8%. On the basis of focusing on all the forest regions extracted through creating a forest mask for each image in time series and merging these to produce an 'anytime' forest mask, the spatiotemporal dynamics of forest were analyzed on the basis of the acquired information of multi-type forest changes and classification. The forests are principally distributed in the core zone of West Donting Lake surrounding the water body and the southwestern mountains. The forest changes in the core zone and low elevation region are prevalent and frequent. The variation of forest areas in West Dongting Lake experienced three steps: rapid expansion of forest plantation from 2000 to 2005, relatively steady from 2006 to 2011, and continuous decline since 2011, mainly caused by anthropogenic factors, such as government policies and economic profits. This study demonstrated the applicability of the integrated BFAST method to detect multi-type forest changes by using dense Landsat time series in the subtropical wetland ecosystem with low data availability. [ABSTRACT FROM AUTHOR]

Indonesia has experienced extensive land-cover change and frequent vegetation and land fires in the past few decades. We combined a new land-cover dataset with satellite data on the timing and location of fires to make the first detailed assessment of the association of fire with specific land-cover transitions in Riau, Sumatra. During 1990 to 2017, secondary peat swamp forest declined in area from 40,000 to 10,000 km2 and plantations (including oil palm) increased from around 10,000 to 40,000 km2. The dominant land use transitions were secondary peat swamp forest converting directly to plantation, or first to shrub and then to plantation. During 2001–2017, we find that the frequency of fire is greatest in regions that change land-cover, with the greatest frequency in regions that transition from secondary peat swamp forest to shrub or plantation (0.15 km−2 yr−1). Areas that did not change land cover exhibit lower fire frequency, with shrub (0.06 km−2 yr−1) exhibiting a frequency of fire >60 times the frequency of fire in primary forest. Our analysis demonstrates that in Riau, fire is closely connected to land-cover change, and that the majority of fire is associated with the transition of secondary forest to shrub and plantation. Reducing the frequency of fire in Riau will require enhanced protection of secondary forests and restoration of shrub to natural forest. [ABSTRACT FROM AUTHOR]

The sequestration of atmospheric carbon (C) in forests has partially offset C emissions in the United States (US) and might reduce overall costs of achieving emission targets, especially while transportation and energy sectors are transitioning to lower-carbon technologies. Using detailed forest inventory data for the conterminous US, we estimate forests' current net sequestration of atmospheric C to be 173 Tg yr−1, offsetting 9.7% of C emissions from transportation and energy sources. Accounting for multiple driving variables, we project a gradual decline in the forest C emission sink over the next 25 years (to 112 Tg yr−1) with regional differences. Sequestration in eastern regions declines gradually while sequestration in the Rocky Mountain region declines rapidly and could become a source of atmospheric C due to disturbances such as fire and insect epidemics. C sequestration in the Pacific Coast region stabilizes as forests harvested in previous decades regrow. Scenarios simulating climate-induced productivity enhancement and afforestation policies increase sequestration rates, but would not fully offset declines from aging and forest disturbances. Separating C transfers associated with land use changes from sequestration clarifies forests' role in reducing net emissions and demonstrates that retention of forest land is crucial for protecting or enhancing sink strength. [ABSTRACT FROM AUTHOR]