Increased mortality can promote evolutionary adaptation of forest trees to climate change

Forecasts of rapid climate change raise the question how quickly species can evolutionarily adapt to future climates. The adaptability of forest trees to environmental changes is generally promoted by high levels of genetic diversity and gene flow, but it can also be slowed down by long generation times and low mortality of established trees. Here, we investigate the adaptation of Scots pine (Pinus sylvestris) and Silver birch (Betula pendula) to climate change induced prolongation of the thermal growing season. We use quantitative genetic individual-based simulations to disentangle the relative roles of mortality, dispersal ability and maturation age for the speed of adaptation. The simulations predict that after 100 years of climate change, the genotypic growth period length of both species will lag more than 50% behind the climatically determined optimum. This lag is reduced by increased mortality of established trees, whereas earlier maturation and higher dispersal ability had comparatively minor effects. The evolutionary lag behind environmental change shown in our simulations stresses the importance of accounting for evolutionary processes in forecasts of the future dynamics and productivity of forests. Sensitivity of the adaptation speed to mortality suggests that species experiencing high mortality rates as well as populations subject to regular disturbances such as storms or fires might be the quickest to adapt to a warming climate.     

How geographic and climatic factors affect the adaptation of Douglas-fir provenances to the temperate continental climate zone in Europe

European Journal of Forest Research - The contribution of Douglas-fir (Df) to European forests is likely to increase as the species is a potential adaptation option to climate change. In this...     

Exploring adaptation to climate change in the forests of central Nova Scotia, Canada

The threat of climate change is now recognized as an imminent issue at the forefront of the forest sector. Incorporating adaptation to climate change into forest management will be vital in the continual and sustainable provision of forest ecosystem services. The objective of this study is to investigate climate change adaptation in forest management using the landscape disturbance model LANDIS-II. The study area was comprised of 14,000 ha of forested watersheds in central Nova Scotia, Canada, managed by Halifax Water, the municipal water utility. Simulated climate change adaptation was directed towards three components of timber harvesting: the canopy-opening size of harvests, the age of harvested trees within a stand, and the species composition of harvested trees within a stand. These three adaptation treatments were simulated singly and in combination with each other in the modeling experiment. The timber supply was found to benefit from climate change in the absence of any adaptation treatment, though there was a loss of target tree species and old growth forest. In the age treatment, all trees in a harvested stand at or below the age of sexual maturity were exempt from harvesting. This was done to promote more-rapid succession to climax forest communities typical of the study area. It was the most effective in maintaining the timber supply, but least effective in promoting resistance to climate change at the prescribed harvest intensity. In the composition treatment, individual tree species were selected for harvest based on their response to climate change in previous research and on management values at Halifax Water to progressively facilitate forest transition under the altered climate. This proved the most effective treatment for maximizing forest age and old-growth area and for promoting stands composed of climatically suited target species. The size treatment was aimed towards building stand complexity and resilience to climate change, and was the most influential treatment on the response of timber supply, forest age, and forest composition to timber harvest when it was combined with other treatments. The combination of all three adaptation treatments yielded an adequate representation of target species and old forest without overly diminishing the timber supply, and was therefore the most effective in minimizing the trade-offs between management values and objectives. These findings support a diverse and multi-faceted approach to climate change adaptation.     

Perspectives in dryland restoration: approaches for climate change adaptation

Reforestation efforts in dryland ecosystems frequently encounter drought and limited soil productivity, although both factors usually interact synergistically to worsen water stress for outplanted seedlings. Land degradation in drylands (e.g. desertification) usually reduces soil productivity and, especially, soil water availability. In dry sub-humid regions, forest fires constitute a major disturbance affecting ecosystem dynamics and reforestation planning. Climate change projections indicate an increase of drought and more severe fire regime in many dryland regions of the world. In this context, the main target of plantation technology development is to overcome transplant shock and likely adverse periods, and in drylands this is mostly related to water limitations. In this paper, we discuss some selected steps that we consider critical for improving success in outplanting woody plants, both under current and projected climate change conditions including: (1) Plant species selection, (2) Improved nursery techniques, and (3) Improved planting techniques. The number of plant species used in reforestation is increasing rapidly, moving from a reduced set of well-known, easy-to-grow, widely used species, to a large variety of promising native species. Available technologies allow for reintroducing native plants and recovering critical ecosystem functions for many degraded drylands. However, climate change projections introduce large uncertainties about the sustainability of current reforestation practices. To cope with these uncertainties, adaptive restoration approaches are suggested, on the basis of improved plant quality, improved techniques for optimizing rain use efficiency in plantations, and exploring native plant species, including provenances and genotypes, for their resilience to fire and water use efficiency.     

Mangrove management for climate change adaptation and sustainable development in coastal zones

Due to their prevalence in developing countries and the range of ecosystem services they provide, projects aimed at promoting mangroves align with several of the UN Sustainable Development Goals—specifically Goals 13, 14, and 15—which concern adaptation to climate change and the sustainable management of forest and coastal resources. Although mangroves themselves are sensitive to climate change, they also provide services that would help reduce damages, by sequestering carbon, enhancing coastline stability, and protecting coastal settlements from tropical storm surges. In particular, mangroves can rapidly colonize and stabilize intertidal sediments, promoting coastal accretion to reduce the impact of sea level rise. The Government of Bangladesh has established mangrove plantations with the intent to accelerate accretion and stabilize 120,000ha of coastland. As a case study, this paper uses GIS data on coastal dynamics and land cover to evaluate the effectiveness of mangrove plantations for facilitating accretion and preventing erosion in Bangladesh. The results indicate that plantation areas experience greater rates of accretion relative to erosion than non-plantation areas, confirming that mangroves have an important role to play in the sustainable development of coastal regions.     

Prediction of the suitable distribution of Eucalyptus grandis in China and its responses to climate change

New Forests - Assessment of potentially suitable geographic areas in China and their response to climate change can provide a reference for sustainable development of Eucalyptus grandis...     

Forest management for mitigation and adaptation to climate change: Insights from long-term silviculture experiments

Developing management strategies for addressing global climate change has become an increasingly important issue influencing forest management around the globe. Currently, management approaches are being proposed that intend to (1) mitigate climate change by enhancing forest carbon stores and (2) foster adaptation by maintaining compositionally and structurally complex forests. However, little is known about the compatibility of these two objectives or the long-term efficacy of a given management regime at simultaneously achieving adaptation and mitigation. To address this need, we examined stand-level carbon and complexity responses using five long-term (>50 yrs) silviculture experiments within the upper Great Lakes region, USA. In particular, live tree carbon stores and sequestration rates, and compositional and structural complexity were analyzed from three thinning experiments in Pinus resinosa and two selection method experiments in northern hardwood systems to elucidate the long-term effects of management on these ecosystem attributes and the general compatibility of mitigation and adaptation objectives.As expected, we observed a general increase in large tree densities with stand age and positive relationships between stand stocking level and live tree carbon stores. More importantly, our results clearly identify tradeoffs between the achievement of mitigation and adaptation objectives across each study. For example, maintaining higher stocking levels (i.e., enhanced mitigation by increasing carbon stores) resulted in decreases in stand-level structural and compositional complexity (i.e., reduced adaptation potential). In addition, rates of live tree carbon increment were also the lowest within the highest stocking levels; despite the benefits of these stand conditions to maximizing carbon stores. Collectively, these findings underscore the importance of avoiding rigid adherence to a single objective, such as maximum on-site carbon stores, without recognizing potential consequences to other ecosystem components crucial to ensuring long-term ecosystem functioning within the context of environmental change. One potential stand-level strategy for balancing these goals may be to employ multi-aged management systems, such as irregular shelterwood and selection systems, that maintain a large proportion of carbon stores in retained mature trees while using thinning to create spatial heterogeneity that promotes higher sequestration rates in smaller, younger trees and simultaneously enhances structural and compositional complexity.     

民勤西沙窝生态气候变化原因探究

:70～ 8 0年代初期当地生态气候良性发展的主要原因 :一是 5 0～ 60年代大面积营造固沙林 ,防护功能随林地面积的增大和林分都闭度增加而增强。二是水资源强度开发 ,但水资源亏缺结果尚未显现出来。 80年代中期以来当地生态气候恶化 ,最根本的原因是大量超采地下水 ,地下水位急剧下降所致。其次是固沙林密度过大 ,到沙丘水分不够时大面积衰败死亡。营造固沙林是改善沙区生态气候环境的有效措施。但营造固沙林应采用其他治沙措施 ,必须以保护和合理利用水资源为先决条件 ;人工固沙林的合理密度 ,应该以不同沙区水分条件可供给某种植物持续生存、生长的密度为限 ;只有综合考虑多系统之间的关系 ,进行综合治沙 ,才能克服前述急功近利的短期行为 ,实现生态环境的持续稳定     

Effect of Japan Sea climate on geographic distribution ofCastanopsis sieboldii andC. cuspidata

The geographic distributions ofCastanopsis sieboldii andCastanopsis cuspidata overlap each other on the Pacific coast of Japan, but on the Japan Sea coastC. sieboldii tends to dominate at similar temperatures. The authors attempted to explain this phenomenon by analyzing the effects of climatic factors. Nuts were collected from the Pacific and Japan Sea coasts of the Kinki and Chugoku districts, and the nut characteristics and the number of layers of epidermis in the leaves of the seedlings were investigated. The distribution ofC. sieboldii andC. cuspidata was satisfactorily explained by a multiple regression equation that was developed using three climatic factors: maximum snow depth in winter, lowest temperature in the coldest month, and annual mean temperature, out of fourteen such factors that were considered. The estimated distribution ofC. sieboldii andC. cuspidata from the multiple regression equation agreed with 66.2% of the actual observations.     

Exploring the role of forest resources in reducing community vulnerability to the heat effects of climate change

While the growing literature on forest ecosystem services has examined the value and significance of a range of services, our understanding of the health-related benefits of ecosystem services from forests is still limited. To characterize the role of forest resources in reducing community vulnerability to the heat effects of climate change, a general index of heat vulnerability (HEVI) was developed through Principle Components Analysis (PCA) and subsequently used within ANVOA and Poisson regression to assess the relationship between the amount and type of forest resources (species, management regime, spatial pattern) and a county's vulnerability to the heat effects of climate change. Results of the ANOVA showed significant differences in the extent and characteristics of forests among counties experiencing different levels of heat vulnerability. The Poisson regression using county heat mortality as the dependent variable found forest characteristics to have a significant influence on heat mortality when other determinants of vulnerability were controlled. A negative and significant relationship was specifically found between forest area and heat related mortality, which supports the hypothesis that the extent of forest coverage helps to alleviate vulnerability associated with heat effects. These findings have important implications for understanding the role of forest ecosystem services in reducing a community's vulnerability to the heat effects of climate change. Findings will also be useful in guiding land use planning and preserving desirable forest characteristics to help communities adapt to climate change.     

Long-term adaptation potential of Central European mountain forests to climate change: a GIS-assisted sensitivity assessment

An ecological risk assessment is described for determining the adaptation potential of the approximately 11 000 Swiss Forest Inventory points (FIP) to a hypothetically changing climate. The core of the study is a spatially explicit forest community model that generates estimates of the potential natural vegetation for the entire potential forest area of Switzerland under today's as well as under altered climate regimes. The model is based on the Bayes formula. The probabilities of the communities occurring along ecological gradients are derived from empirical data featuring the relationships between quasi-natural vegetation types and measured site variables. Bioclimatological input variables are the quotient between July temperature and annual precipitation (model version A) or mean annual temperature (model version B). Other site variables include aspect, acidity of top soil and, to account for continentality, geographical region. Climate change scenarios are defined as follows: ‘Moderate climate change’ implies an increase of the mean annual temperature of 4°C to 1.4°C depending on the region (model version B) or an increase of the July temperature of 1.5°C (model version A). ‘Strong climate change’ implies an increase of the mean annual temperature of 2°C to 2.8°C (model version B) or an increase of the July temperature of 3.0°C (model version A).

The simulation experiment showed that the geographical distribution of 15 potential natural forest types (distinguished on the basis of floristic affinities) varies considerably with changing temperature. Under moderate warming 30–55% of the FIP change their potential natural vegetation type, whereas under strong climate change the values increase to 55–89% depending on the model version used. In the ecological risk assessment the existing tree species composition on any FIP was compared with the expected tree species composition under today's as well as under altered climate regimes. A major finding indicated that, under the current climate conditions, approximately 25–30% (depending on the model version used) of all FIP must be considered as poorly adapted, i.e. less than 20% of the actual basal area consists of tree species that are expected as dominating taxa. This definition applies for trees with a diameter at breast height (DBH) ≥ 12 cm. Moderate warming increases the percentage of poorly adapted FIP by 5–10% (relative to all FIP considered), strong warming leads to a 10–30% increase of poorly adapted FIP (relative to all FIP considered). If trees with a DBH < 12cm are considered, the percentage of FIP that have to be classified as poorly adapted is reduced significantly. There are strong regional differences as exhibited in risk maps of 10 km × 10 km resolution.     

Walnut (Juglans spp.) ecophysiology in response to environmental stresses and potential acclimation to climate change

? Context

Walnuts (Juglans spp.) are ecologically and commercially important trees, yet synthesis of past and current research findings on walnut ecophysiology is lacking, especially in terms of potential acclimation to climate change.

? Aims

This study aims to (1) investigate walnut ecophysiology by comparing its attributes to associated deciduous angiosperms, (2) address potential acclimation of walnut to climate change, and (3) identify areas for prioritization in future research.

? Results

There is considerable uncertainty regarding the magnitude of potential effects of climate change on walnut. Some studies tend to indicate walnut could be negatively impacted by climate change, while others do not. Walnut may be at a disadvantage due to its susceptibility to drought and frost injury in current growing regions given the projected increases in temperature and extreme climatic events. Other regions that are currently considered cold for walnut growth may see increased establishment and growth depending upon the rate of temperature increase and the frequency and severity of extreme climatic events.

? Conclusion

Research investigating a combination of environmental factors, such as temperature, carbon dioxide, ozone, water, and nitrogen is needed to (1) better project climate change effects on walnut and (2) develop management strategies for walnut acclimation and adaptation to climate change.     

US strategy for forest management adaptation to climate change: building a framework for decision making

Context

Recent policy changes in the USA direct agencies managing federal forests to analyze the potential effects of climate change on forest productivity, water resource protection, wildlife habitat, biodiversity, and other values.

Aims

This paper describes methods developed to (1) assess current risks, vulnerabilities, and gaps in knowledge; (2) engage internal agency resources and external partners in the development of options and solutions; and (3) manage forest resources for resilience, not just in terms of natural ecosystems but in affected human communities as well.

Methods

We describe an approach designed to characterize certain climate change effects on forests, and estimate the effectiveness of response options ranging from resistance to a realignment of management objectives.

Results

Field testing on a 6,300 km² area of conifer forest in the northwestern USA shows this decision model to be useful and cost-effective in identifying the highest sensitivities relating to vegetation management, biological diversity, water resources and forest transportation systems, and building consensus for adaptive strategies and actions.

Conclusions

Results suggest that this approach is an effective means for guiding management decisions to adapt to the effects of climate change, and provides an empirical basis for setting budgetary and management priorities.     

The impacts of climate change on potential natural vegetation distribution

Change in potential natural vegetation (PNV) distribution associated with climate change due to the doubling atmospheric carbon dioxide (2×CO₂) was estimated with a global natural vegetation mapping system based on the modified Kira scheme to the globe and the continents. With an input of widely-distributed global climate data, the system interpolates data onto a 1° latitude by 1° longitude grid over the globe, generates estimates of vegetation type, and produces a composite PNV map. The input climate data corresponding to the 1×CO₂ and 2×CO₂ consists of observations prior to AD 1958 at 2,001 weather stations worldwide and the 2×CO₂ simulation output from the Japan Meteorological Research Institue's General Circulation Model, respectively. As a result of the simulated global warming, the vegetation zones expanded mostly from the tropics toward the poles. PNV area changed by 6.98 billion (G) ha of the total land area (15.04 Gha) and potential forest area corresponding to the closed forest and open forest (woodland) reached 9.74 Gha with the increase of 1.29 Gha. The potential forest area in Europe had obvious advantages to the climate change accompanied with the increase of actual forest area. Although the actual forest area has decreased in North America and Asia, the potential forest area in these continents also benefitted from the climate change. In the end, the remaining continents tended to bear the brunt of the climate change.     

Pertinence of reactive,active, and robust adaptation strategies in forest management under climate change

Key message

Pertinence of alternative adaptation strategies to business as usual, namely reactive, active, and robust adaptation strategies, can be evaluated by incorporating the expected costs and benefits of adaptation, climate change uncertainty, and the risk attitudes of decision-makers.

Context

Forest management is used to coping with risky and uncertain projections and estimates. However, climate change adds a major challenge and necessitates adaptation in many ways.

Aims

This paper highlights the dependency of the decisions on adaptation strategies to four aspects of forest management: (i) the costs of mitigating undesirable climate change impacts on forests, (ii) the value of ecosystem goods and services to be sustained, (iii) uncertainties about future climate trajectories, and (iv) the attitude of decision-makers towards risk (risk aversion level).

Methods

We develop a framework to evaluate the pertinence of reactive, active, and robust adaptation strategies in forest management in response to climate change.

Results

Business as usual may still be retained if the value of the forest and cost of climate impacts are low. Otherwise, it is crucial to react and facilitate the resilience of affected forest resources or actively adapt in advance and improve forest resistance. Adaptation should be robust under any future climate conditions, if the value of the ecosystem, the impacts from climatic changes, and the uncertainty about climate scenarios are very high.

Conclusion

The decision framework for adaptation should take into account multiple aspects of forest management under climate change towards an active and robust strategy.

     

峨眉山不同海拔冷杉径向生长对气候变化的响应

【目的】研究峨眉山不同海拔冷杉Abies fabri径向生长对气候变化的响应规律。【方法】以冷杉为研究对象,用树轮生态学的方法对峨眉山不同海拔的冷杉进行年轮采样、处理与分析,比较不同海拔冷杉径向生长特征及其与各气候因子之间的关系。【结果】年表统计数据表明,4个年表均具有较高的可靠性,可以用于树木生长与气候关系的研究。不同海拔冷杉径向生长与气候的关系具有明显的海拔差异,海拔2 400 m处冷杉径向生长与当年7月的温度呈显著正相关;海拔2 800 m处冷杉径向生长与当年4-9月的帕尔默干旱指数(PDSI)呈显著正相关;海拔2 900 m处冷杉径向生长与前一年9月和当年4月的温度呈显著负相关,与当年1-9月的PDSI均呈显著正相关;海拔3 000 m处冷杉径向生长和当年3-4月温度呈显著负相关,与当年6-7月的PDSI和当年4月平均相对湿度呈显著正相关。【结论】峨眉山高海拔的冷杉包含有更多的环境信息,对气候变化的响应也更为敏感;高海拔区域冷杉径向生长受到水分的强烈限制,而低海拔区域冷杉径向生长主要受温度影响;冷杉衰亡与气候因子的变化密切相关,随着区域气候的变暖,高海拔地区冷杉可能会进一步衰退。该研究揭示了峨眉山不同海拔冷杉生长动态及其对气候变化响应的敏感性差异,为全球气候变化背景下冷杉林的保护与适应性管理提供科学参考。     

基于生态位模型的石蒜适生区预测

运用预设预测规则的遗传算法(GARP)和最大熵(MaxEnt)两种生态位预测模型,以及受试者工作曲线(ROC)分析方法,预测石蒜属石蒜潜在适生区.结果表明,GARP和MaxEnt模型ROC曲线下面的面积AUC(area under the ROC curve)均值分别为0.910和0.988,MaxEnt模型的AUC值更大,预测结果更准确,运行速度更快,更适合用于石蒜的适生区预测.对环境变量进行刀切法表明,在所有环境变量中,最冷季度平均温度对于石蒜分布的影响(贡献)最大,其次是年均温、最冷月的最低温度和最暖季度降水量,而海拔、降水量变化方差对石蒜分布的影响比较小.预测结果显示,石蒜在世界范围内主要分布在亚洲东部以及亚洲中部一小部分,另外北美洲的东部,欧洲南部一小部分地区也适合其生长.在中国范围内主要分布在云南、贵州、福建、江苏、浙江、安徽、江西、重庆、湖北、湖南等省,以及山东、河南、陕西、甘肃等省南部;四川东部和广东、广西(除了南部沿海地区)均预测为适生区,海南、台湾、西藏部分地区也是适生区.     

Growth response to climate and drought change along an aridity gradient in the southernmost Pinus nigra relict forests

Context

Tree populations at the rear edge of species distribution are sensitive to climate stress and drought. However, growth responses of these tree populations to those stressors may vary along climatic gradients.

Aims

To analyze growth responses to climate and drought using dendrochronology in rear-edge Pinus nigra populations located along an aridity gradient.

Methods

Tree-ring width chronologies were built for the twentieth century and related to monthly climatic variables, a drought index (Standardized Precipitation–Evapotranspiration Index), and two atmospheric circulation patterns (North Atlantic and Western Mediterranean Oscillations).

Results

Growth was enhanced by wet and cold previous autumns and warm late winters before tree-ring formation. The influence of the previous year conditions on growth increased during the past century. Growth was significantly related to North Atlantic and Western Mediterranean Oscillations in two out of five sites. The strongest responses of growth to the drought index were observed in the most xeric sites.

Conclusion

Dry conditions before tree-ring formation constrain growth in rear-edge P. nigra populations. The comparisons of climate-growth responses along aridity gradients allow characterizing the sensitivity of relict stands to climate warming.     

Dynamic response to climate change in the radial growth of Picea schrenkiana in western Tien Shan,ChinaOA

Forests are important ecosystems for economic and social development. However, the response of tree radial growth to climate has produced ‘divergent problems’ at high latitudes under global warming. In this study, the response stability and trend of Picea schrenkiana radial growth to variability in climate factors were analyzed in the mid-latitudes of the western Tien Shan Mountains. Radial growth of P.schrenkiana was mainly limited by minimum and mean temperatures. The divergent responses of ra...