A dramatic increase in bark-beetle (Ips typographus) damage in Norway spruce (Picea abies (L.) Karst.) forests occured in the provinces Upper and Lower Austria in the past decade with the beetle ...outbreak likely driven by climate change. Water shortage in the early growing season appears to weaken the forests. The high supply of beetle-infested timber is reducing wood prices and forests are not meeting policy expectations for a viable bioeconomy. The sink strength of forests has diminished from 12% to 6% of the national greenhouse gas emission budget and may even turn into a source when the disturbance dynamics continue. Consequences cascade through the forest sector. The regional market price for bark-beetle affected timber declined to 30% of the previous level. Small-forest owners who obtain a marginal income from wood products are losing motivation for active forest management. The operational difficulties of cutting affected trees combined with the organization of timber transport to saw-mills are being met by excessive inventories of unprocessed logs at mills. Large forest enterprises can only intermittently absorb higher costs for forest management than be met currently from sales of products. The long-term consequence is lasting reduction of forest productivity and an uncertain future for forestry in Central Europe that may increasingly depend on technological breakthroughs in processing timber from deciduous trees and eventually payments for ecosystem services.
Global warming has the potential to increase soil respiration (RS), one of the major fluxes in the global carbon (C) cycle. RS consists of an autotrophic (RA) and a heterotrophic (RH) component. We ...combined a soil warming experiment with a trenching experiment to assess how RS, RA, and RH are affected. The experiment was conducted in a mature forest dominated by Norway spruce. The site is located in the Austrian Alps on dolomitic bedrock. We warmed the soil of undisturbed and trenched plots by means of heating cables 4 °C above ambient during the snow-free seasons of 2005 and 2006. Soil warming increased the CO₂ efflux from control plots (RS) by ~45% during 2005 and ~47% during 2006. The CO₂ efflux from trenched plots (RH) increased by ~39% during 2005 and ~45% during 2006. Similar responses of RS and RH indicated that the autotrophic and heterotrophic components of RS responded equally to the temperature increase. Thirty-five to forty percent or 1 t C ha⁻¹ yr⁻¹ of the overall annual increase in RS (2.8 t C ha⁻¹ yr⁻¹) was autotrophic. The remaining, heterotrophic part of soil respiration (1.8 t C ha⁻¹ yr⁻¹), represented the warming-induced C loss from the soil. The autotrophic component showed a distinct seasonal pattern. Contribution of RA to RS was highest during summer. Seasonally derived Q₁₀ values reflected this pattern and were correspondingly high (5.3-9.3). The autotrophic CO₂ efflux increase due to the 4 °C warming implied a Q₁₀ of 2.9. Hence, seasonally derived Q₁₀ of RA did not solely reflect the seasonal soil temperature development.
Since the inception of the Sustainable Development Goals (SDGs) in 2015, there has been much conceptual progress on the linkages across the 17 goals and their 169 targets. While this kind of ...conceptualization is an essential first step, action must now move towards systematic policy design, implementation, and multi-stakeholder collaborations that can translate such understanding into concrete results. This study is a reality check of such quasi-political global development agendas by the United Nations and its implications on Austrian forestry. Although forestry is not a goal in itself, forests as an element have been included under SDG15 (Life on Land). In this study, the linkages of forestry with potential synergies or trade-offs within and between the SDGs have been assessed through a literature survey and complemented with the perception of opinion leaders across the Austrian forestry sector on the same. The insights about awareness, design, implementation, and the necessity of mainstreaming the SDGs into the policy structure of Austria were reviewed. Besides facilitating the goals of sustainable forest management (SFM) in Austria, the SDG15 is not only strongly related to, but is likely to aid, the achievement of other SDGs, such as human health (SDG3), provision of clean water (SDG6), affordable & clean energy (SDG7), and climate action (SDG13). The opinion leaders perceive the SDGs as well-placed but broad. Some this broadness is a positive aspect of the SDGs. On the other hand, the 15-year (2015–2030) tenure of the SDGs is perceived to be inadequate to match the temporal scale of forest development. Apparently, the success of the SDGs will strictly depend upon coordination, governance, and most importantly, awareness among all stakeholders. Therefore, in addition to “leaving no one behind”, the SDGs must evidently provide incentives benefitting everybody.
Climate change may considerably impact the carbon (C) dynamics and C stocks of forest soils. To assess the combined effects of warming and reduced precipitation on soil CO2 efflux, we conducted a ...two‐way factorial manipulation experiment (4 °C soil warming + throughfall exclusion) in a temperate spruce forest from 2008 until 2010. Soil was warmed by heating cables throughout the growing seasons. Soil drought was simulated by throughfall exclusions with three 100 m2 roofs during 25 days in July/August 2008 and 2009. Soil warming permanently increased the CO2 efflux from soil, whereas throughfall exclusion led to a sharp decrease in soil CO2 efflux (45% and 50% reduction during roof installation in 2008 and 2009, respectively). In 2008, CO2 efflux did not recover after natural rewetting and remained lowered until autumn. In 2009, CO2 efflux recovered shortly after rewetting, but relapsed again for several weeks. Drought offset the increase in soil CO2 efflux by warming in 2008 (growing season CO2 efflux in t C ha−1: control: 7.1 ± 1.0; warmed: 9.5 ± 1.7; warmed + roof: 7.4 ± 0.3; roof: 5.9 ± 0.4) and in 2009 (control: 7.6 ± 0.8; warmed + roof: 8.3 ± 1.0). Throughfall exclusion mainly affected the organic layer and the top 5 cm of the mineral soil. Radiocarbon data suggest that heterotrophic and autotrophic respiration were affected to the same extent by soil warming and drying. Microbial biomass in the mineral soil (0–5 cm) was not affected by the treatments. Our results suggest that warming causes significant C losses from the soil as long as precipitation patterns remain steady at our site. If summer droughts become more severe in the future, warming induced C losses will likely be offset by reduced soil CO2 efflux during and after summer drought.
Abstract
Climate warming may induce shifts in soil microbial communities possibly altering the long-term carbon mineralization potential of soils. We assessed the response of the bacterial community ...in a forest soil to experimental soil warming (+4 °C) in the context of seasonal fluctuations. Three experimental plots were sampled in the fourth year of warming in summer and winter and compared to control plots by 16S rRNA gene pyrosequencing. We sequenced 17 308 amplicons per sample and analysed operational taxonomic units at genetic distances of 0.03, 0.10 and 0.25, with respective Good's coverages of 0.900, 0.977 and 0.998. Diversity indices did not differ between summer, winter, control or warmed samples. Summer and winter samples differed in community structure at a genetic distance of 0.25, corresponding approximately to phylum level. This was mainly because of an increase of Actinobacteria in winter. Abundance patterns of dominant taxa (> 0.06% of all reads) were analysed individually and revealed, that seasonal shifts were coherent among related phylogenetic groups. Seasonal community dynamics were subtle compared to the dynamics of soil respiration. Despite a pronounced respiration response to soil warming, we did not detect warming effects on community structure or composition. Fine-scale shifts may have been concealed by the considerable spatial variation.
We reviewed the experimental evidence for long-term carbon (C) sequestration in soils as consequence of specific forest management strategies. Utilization of terrestrial C sinks alleviates the burden ...of countries which are committed to reducing their greenhouse gas emissions. Land-use changes such as those which result from afforestation and management of fast-growing tree species, have an immediate effect on the regional rate of C sequestration by incorporating carbon dioxide (CO
2) in plant biomass. The potential for such practices is limited in Europe by environmental and political constraints. The management of existing forests can also increase C sequestration, but earlier reviews found conflicting evidence regarding the effects of forest management on soil C pools. We analyzed the effects of harvesting, thinning, fertilization application, drainage, tree species selection, and control of natural disturbances on soil C dynamics. We focused on factors that affect the C input to the soil and the C release via decomposition of soil organic matter (SOM). The differentiation of SOM into labile and stable soil C fractions is important. There is ample evidence about the effects of management on the amount of C in the organic layers of the forest floor, but much less information about measurable effects of management on stable C pools in the mineral soil. The C storage capacity of the stable pool can be enhanced by increasing the productivity of the forest and thereby increasing the C input to the soil. Minimizing the disturbances in the stand structure and soil reduces the risk of unintended C losses. The establishment of mixed species forests increases the stability of the forest and can avoid high rates of SOM decomposition. The rate of C accumulation and its distribution within the soil profile differs between tree species. Differences in the stability of SOM as a direct species effect have not yet been reported.
Climate change adaptation needs to receive extensive attention in the forestry sector. While measures are being applied in federal forests and large private properties, it remains unclear how ...small-scale private forest owners, with a property <20ha, perceive the possible influence of climate change and whether they will approach required activities. While in the past, the majority of private forest owners had ties to agriculture and cultivated farmland alongside their forests, recent studies revealed new trends and significant deviations from established norms and beliefs. Therefore, this study aimed to investigate the motivations for forest ownership, current management practices, and perception of and adaptability to climate change, to discuss successful approaches for information campaigns, advisory services, and monetary incentives. The study applied a questionnaire with an embedded choice experiment, which obtained a thorough understanding of the salient factors influencing decision-making by surveying 919 forest owners across Austria. Results show that small-scale private forest owners are not homogenous. Three distinct segments were identified (utility oriented, recreation oriented, and tradition conscious forest owners) which reacted differently to provided management options and incentives. However, even under a worst-case scenario setting, 84% of forest owners would select some sort of management over no procedure, indicating that forest management is not generally rejected. Information campaigns should rather focus on soft management leading to attractive, stable and highly diverse forest stands resilient to climate change than on cost efficiency and financial benefits. Therefore, advisory services need to convey, that all forest measures are performed with special care and under consideration of the remaining forest and that each stand is treated individually with adequate equipment. Increasing monetary incentives, such as funding, barely influences forest owners' decision-making and are therefore deemed unfeasible and unable to motivate the owners to undertake climate change adaptation measures. The study shows that a segmentation based on management behavior and preferences rather than on predefined characteristics has the potential to define a new state of the art. Overall, climate change adaptation through tailored forest management is highly supported by the presented findings.
•Detailed segmentation and description of Austrian small-scale private forest owners•Adaptation depends on proposed management strategies: soft procedures are preferred.•Technologically advanced management with harvesters and intensive cutting is rejected.•Payments and funding have little influence on the decision-making.•Tailored services can provide sufficient incentives for adaptation of management.
A change in tree species composition in Central Europe to increase the resilience of forests when coping with climate change effects is imminent. We evaluated the present and expected future role of ...the European beech, (Fagus sylvatica L.), with respect to the expansion of its habitat and its stem. We assessed the current relevance of beech from data of the Austrian Forest Inventory 2007/09, and analyzed forest policies promoting the establishment of beech forests. We simulated forest growth with the model CALDIS, linked with the timber-market model FOHOW2. We used a business-as-usual (BAU) forest management strategy under moderate (RCP 4.5 BAU) or extreme (RCP 8.5 BAU) climate change. We also simulated an extreme climate change scenario with a forced change in the tree species composition (RCP 8.5 Change Species). Beech occurs in Austrian forests over the elevational gradient of 250 to 1600 m a.s.l. In low elevation, it forms beech-dominated forests, often for the supply of the domestic fuelwood demand. In mountain regions, beech enriches the diversity of Norway spruce, (Picea abies (L.) H. Karst.)-dominated forests. In a BAU setting, the habitat of beech increases only slightly in both climate scenarios. The scenario ‘RCP 8.5 Change Species’ increases the habitat of beech in the next 60 years considerably. With progressing warming, other broadleaved tree species gain relevance. The vulnerability to drought and pathogens are limiting factors for Austrian beech forests. The future habitat depends on many factors such as the ability of forests to cope with climate change, the confidence to arising market opportunities of beech timber in the wake of technological progress, and financial and non-financial incentives for the implementation of adaptive forest management.
The respiration of forest soils and the major factors controlling its rate are fairly well understood. The process is of utmost significance because its balance with the fixation of CO2 in the ...biomass defines whether a particular site is a source or sink of atmospheric CO2. Currently, the measurement of soil respiration in the field requires rather expensive experimental installations. Nevertheless, there are still some caveats in our understanding, such as the separation of autotrophic and heterotrophic soil respiration, the relevance of different groups of soil organisms, the effect of ecosystem disturbances in different types of forests on soil respiration with respect to magnitude and duration, the adaptation of soil respiration to changing site conditions, and the regional prediction of soil respiration, based on proxy data. Technical progress and additional contributions on process understanding will put us in the position of better predictions of the forest soil respiration. We encourage studies from all fields, including experimental studies, monitoring approaches and models, to contribute to this Special Issue in order to promote knowledge and adaptation strategies for the preservation, management, and future development of forest ecosystems.
Question:
We compared the soil organic carbon stock of the forests of an entire country. The objective of our research was establishing the differences between coniferous or deciduous forests with ...respect to soil carbon stocks. The question is relevant because coniferous forests are increasingly damaged by abiotic and biotic disturbances that are related to climate change. Deciduous forests are considered to be less vulnerable. Their soils are expected to be more persistent and reliable sinks for carbon dioxide.
Methods:
Soil data are available from the Austrian Forest Soil Survey. Soils have been sampled on sites of the Austrian Forest Inventory. The data were stratified according to geology (calcareous vs. silicatic bedrock), orientation of the slopes, and forest type (coniferous vs. mixed-deciduous forest). These data were used to establish ground truth of soil organic carbon stocks. Further, we had simulation results of a coupled forest growth/soil carbon model. The scenarios built on the results of the Forest Inventory 2007/09 and reflect a business-as-usual forest management vs. a climate-change adaptation scenario where forest managers replace coniferous with deciduous forests if site conditions permit it. The simulations were performed with the forest growth simulator CÂLDIS and the soil carbon model Yasso07.
Results:
Based on the Austrian Forest Soil Survey carbon stocks of coniferous forests were consistently higher than in mixed-deciduous forests. This result applies both for the organic litter layer and the mineral soil to a depth of 50 cm. The depth gradients of carbon were similar in both forest types. The simulation under a strong warming scenario showed an increase in the carbon stocks of soils when conifers are replaced by deciduous tree species. In the 150-year simulation the majority of forest sites will become suitable for deciduous forests. The build-up of a large soil organic carbon stock is driven by the stronger harvesting pressure on the remaining coniferous forests. Deciduous forests were in lesser demand and developed under a light forest intervention regime. However, toward the end of the century, when the temperature level is far above present levels, the soil organic carbon stocks declined.
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