Articles containing the keyword 'climate change'

The carbon reservoir of ecosystems was estimated based on field measurements for forests and peatlands on an area in Finland covering 263,000 km² and extending about 900 km across the boreal zone from south to north. More than two thirds of the reservoir was in peat, and less than ten per cent in trees. Forest ecosystems growing on mineral soils covering 144,000 km² contained 10–11 kg C m^-2 on an average, including both vegetation (3.4 kg C m^-2) and soil (uppermost 75 cm; 7.2 kg C m^-2). Mire ecosystems covering 65,000 km² contained an average of 72 kg C m^-2 as peat. For the landscape consisting of peatlands, closed and open forests, and inland water, excluding arable and built-up land, a reservoir of 24.6 kg C m^-2 was observed. This includes the peat, forest soil and tree biomass. This is an underestimate of the true total reservoir, because there are additional unknown reservoirs in deep soil, lake sediments, woody debris, and ground vegetation. Geographic distributions of the reservoirs were described, analysed and discussed. The highest reservoir, 35–40 kg C m^-2, was observed in sub-regions in central western and north western Finland. Many estimates given for the boreal carbon reservoirs have been higher than those of ours. Either the Finnish environment contains less carbon per unit area than the rest of the boreal zone, or the global boreal reservoir has earlier been overestimated. In order to reduce uncertainties of the global estimates, statistically representative measurements are needed especially on Russian and Canadian peatlands.

• Kauppi, E-mail: pk@mm.unknown
• Hänninen, E-mail: ph@mm.unknown
• Henttonen, E-mail: hh@mm.unknown
• Ihalainen, E-mail: ai@mm.unknown
• Lappalainen, E-mail: el@mm.unknown
• Posch, E-mail: mp@mm.unknown
• Starr, E-mail: ms@mm.unknown
• Tamminen, E-mail: pt@mm.unknown

Addressing the potential impact of climate change on boreal forest ecosystems will require a range of new conservation techniques. During the early 1990s, the scope of WWF's (the World Wide Fund for Nature) forest policy work has broadened from a focus on tropical moist forests to a more general consideration of all the world's forests. Climate change is only one of a series of threats currently facing boreal forests.

Planning conservation strategies that take account of global warming is not easy when there are many computer models of climate change, sometimes predicting very different ecological effects. Climate change could result in some particularly extreme problems for the boreal forest biome. A summary of the problems and opportunities in boreal forests is presented. WWF has also been drawing up strategies for conservation on a global, regional and national level. The organization has concluded that conservation strategies aimed at combatting climate change need not be in direct conflict with other conservation planning requirements. However, proposals have emerged for ways to address the impacts of climate change that would have detrimental impacts on existing conservation plans.

• Dudley, E-mail: nd@mm.unknown
• Jeanrenaud, E-mail: jj@mm.unknown
• Markham, E-mail: am@mm.unknown

As a follow-up on acid rain programmes many countries, e.g. Finland, the Netherlands, Sweden, launched national research programmes on Climate Change by the end of the eighties. Other countries centred new programmes on Global Change, such as Belgium, United Kingdom, Germany, Canada. Also, the European Community included the climate issue in the research programme 'Environment & Climate'. The conclusion of the Intergovernmental Panel on Climate Change (IPCC) shifted in the successive assessment reports from possible climate change to actual climate change. The paper describes the first and second phase of the Dutch Climate Change Research Programme, and discusses the future of the programme.

• Rompaey, E-mail: rr@mm.unknown

There is no doubt that tree survival, growth, and reproduction in North America's boreal forests would be directly influenced by the projected changes in climate if they occur. The indirect effects of climate change may be of even greater importance, however, because of their potential for altering the intensity, frequency, and perhaps even the very nature of the disturbance regimes which drive boreal forest dynamics. Insect defoliator populations are one of the dominating disturbance factors in North America's boreal forests and during outbreaks trees are often killed over vast forest areas. If the predicted shifts in climate occur, the damage patterns caused by insects may be considerably changed, particularly those of insects whose temporal and spatial distributions are singularly dependent on climatic factors. The ensuing uncertainties directly affect depletion forecasts, pest hazard rating procedures, and long-term planning for pest control requirements. Because the potential for wildfire often increases in stands after insect attack, uncertainties in future insect damage patterns also lead to uncertainties in fire regimes. In addition, because the rates of processes key to biogeochemical and nutrient recycling are influenced by insect damage, potential changes in damage patterns can indirectly affect ecosystem resilience and the sustainability of the multiple uses of the forest resource.

In this paper, a mechanistic perspective is developed based on available information describing how defoliating forest insects might respond to climate warming. Because of its prevalence and long history of study, the spruce budworm, Choristoneura fumiferana Clem. (Lepidoptera: Tortricidae), is used for illustrative purposes in developing this perspective. The scenarios that follow outline the potential importance of threshold behaviour, historical conditions, phenological relationships, infrequent but extreme weather, complex feedbacks, and natural selection. The urgency of such considerations is emphasized by reference to research suggesting that climate warming may already be influencing some insect lifecycles.

• Fleming, E-mail: rf@mm.unknown

The present study is the first attempt to carry out an inventory of greenhouse gas (GHG) fluxes in the forests of Estonia. The emission and uptake of CO₂ as a result of forest management, forest conversion and abandonment of cultivated lands in Estonia was estimated. The removal of GHG by Estonian forests in 1990 exceeded the release about 3.3 times. Changes in the species composition and productivity of forest sites under various simulated climate change scenarios have been predicted by using the Forest Gap Model for the central and coastal areas of Estonia. The computational examples showed that the changes in forest community would be essential.

• Mandre, E-mail: mm@mm.unknown
• Klõseiko, E-mail: jk@mm.unknown
• Reisner, E-mail: vr@mm.unknown
• Tullus, E-mail: ht@mm.unknown

A gap-model was used with forest inventory data in taking ground-true site, soil and tree characteristics into account in predicting the effects of climate change on forests. A total of 910 permanent sample plots established in the course of national forest inventory (NFI) in Finland and located on mineral soil sites in southern Finland were selected as the input data. The climatological input used in the simulations consisted of interpolated means of and deviations from long-term local temperature and precipitation records. The policy-oriented climate scenarios of SILMU (Finnish Research Programme on Climate Change) were used to describe the climate change. The temperature changes in the climate scenarios were increases of ca. +1.1 °C (low), +4.4 °C (medium) and +6.6 °C (high) compared to the current climate in 110 years. The simulation period was 110 years covering the time years 1990–2100.

Southern Finland, divided into fifteen forestry board districts, was used as the study region. Regional development of stand volume, cutting yield, and total wood production of forests under different climate scenarios were examined. The annual average growth in simulations under current climate was close to that observed in NFL Forests benefited from a modest temperature increase (Scenario 2), but under Scenario 1 the growing stock remained at a lower level than under the current climate in all parts of the study region. In wood production and cutting yield there were regional differences. In the southern part of the study regional wood production under Scenario 1 was ca. 10% lower than under the current climate, but in the eastern and western parts wood production was 5–15% higher under Scenario 1 than under the current climate. The relative values of total wood production and cutting yield indicated that the response of forests to climate change varied by geographical location and the magnitude of climate change. This may be a consequence of not just varying climatic (e.g. temperature and precipitation) and site conditions, but of varying responses by different kind of forests (e.g. forests differing in tree species composition and age).

• Talkkari, E-mail: at@mm.unknown

To project the changes in wood production of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) in Finland as a result of climate change, two separate studies were made. The first study, at the Faculty of Forestry, University of Joensuu, based its projections on mathematical models; the second one, at the Finnish Forest Research Institute, based projections on measurements of wood production in two series of aged provenance experiments. The results of the two studies were similar for both species: after a 4°C increase of the annual mean temperature a drastic increase in wood production in northern Finland, but little effect, or even some decrease in the southern part of the country. However, the assumptions used in the two studies differed. One important difference was that in the models the temperature is assumed to be increasing gradually over the years, whereas in the provenance experiments, climate changed immediately when the seedlings were transferred to the planting sites. Another problem with the provenance experiments is that when material is moved in a north-south direction in Finland, not only temperature but also photoperiod changes markedly. To compare these two studies, site factors (e.g. soil type, temperature, precipitation) and silvicultural factors (e.g. plant spacing, survival, time of thinning, thinning intensity) from the provenance experiments were included a variable in the mathematical models.

• Beuker, E-mail: eb@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Kolström, E-mail: mk@mm.unknown

The productivity of Scots pine (Pinus sylvestris L.) under changing climatic conditions in the southern part of Finland was studied by scenario analysis with a gap-type forest ecosystem model. Standard simulations with the model predicted an increased rate of growth and hence increased productivity as a result of climatic warming. The gap-type model was refined by introducing an overwintering sub-model describing the annual growth cycle, frost hardiness, and frost damage of the trees. Simulations with the refined gap-type model produced results conflicting with those of the standard simulation, i.e., drastically decreased productivity caused by mortality and growth-reducing damage due to premature dehardening in the changing climate. The overwintering sub-model was tested with frost hardiness data from Scots pine saplings growing at their natural site 1) under natural conditions and 2) under elevated temperature condition, both in open-top chambers. The model predicted the frost hardiness dynamics quite accurately for the natural conditions while underestimating the frost hardiness of the saplings for the elevated temperature conditions. These findings show that 1) the overwintering sub-model requires further development, and 2) the possible reduction of productivity caused by frost damage in a changing climate is less drastic than predicted in the scenario analysis. The results as a whole demonstrated the need to consider the overwintering of trees in scenario analysis carried out with ecosystem model for boreal conditions. More generally, the results revealed a problem that exists in scenario analysis with ecological models: the accuracy of a model in predicting the ecosystem functioning under present climatic condition does not guarantee the realism of the model, nor for this reason the accuracy for predicting the ecosystem functioning under changing climatic conditions. This finding calls for the continuous rigorous experimental testing of ecological models used for assessing the ecological implications of climatic change.

• Hänninen, E-mail: hh@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Leinonen, E-mail: il@mm.unknown
• Repo, E-mail: tr@mm.unknown

A system of zonality in Siberia has been formed under the control of continentality, which provides the heat and humidity regimes of the forest provinces. Three sectors of continentality and four to six boreal sub-zone form a framework for the systematization of the different features of land cover in Siberia. Their climatic ordination provides the fundamental basis for the principal potential forest types (composition, productivity) forecasting the current climate. These are useful in predicting the future transformations and succession under global change.

• Nazimova, E-mail: dn@mm.unknown
• Polikarpov, E-mail: np@mm.unknown

An equilibrium model driven by climatic parameters, the Siberian Vegetation Model, was used to estimate changes in the phytomass of Siberian vegetation under climate change scenarios (CO₂ doubling) from four general circulation models (GCM's) of the atmosphere. Ecosystems were classified using a three-dimensional climatic ordination of growing degree days (above a 5 °C threshold), Budyko's dryness index (based on radiation balance and annual precipitation), and Conrad's continentality index. Phytomass density was estimated using published data of Bazilevich covering all vegetation zones in Siberia. Under current climate, total phytomass of Siberia is estimated to be 74.1 ± 2.0 Pg (petagram = 1,015 g). Note that this estimate is based on the current forested percentage in each vegetation class compiled from forest inventory data.

Moderate warming associated with the GISS (Goddard Institute for Space Studies) and OSU (Oregon State Univ.) projections resulted in a 23–26 % increase in phytomass (to 91.3 ± 2.1 Pg and 93.6 ± 2.4 Pg, respectively), primarily due to an increase in the productive Southern Taiga and Sub-taiga classes. Greater warming associated with the GFDL (General Fluid Dynamics Laboratory) and UKMO (United Kingdom Meteorological Office) projections resulted in a small 3–7 % increase in phytomass (to 76.6 ± 1.3 Pg and 79.6 ± 1.2 Pg, respectively). A major component of predicted change using GFDL and UKMO is the introduction of a vast Temperate Forest-Steppe class covering nearly 40% of the area of Siberia, at the expense of Taiga; with current climate, this vegetation class is nearly non-existent in Siberia. In addition, Sub-boreal Forest-Steppe phytomass double with all GCM predictions. In all four climate change scenarios, the predicted phytomass stock of all colder, northern classes is reduced considerably (viz., Tundra, Fore Tundra, northern Taiga, and Middle Taiga). Phytomass in Sub-taiga increases greatly with all scenarios, from a doubling with GFDL to quadrupling with OSU and GISS. Overall, phytomass of the Taiga biome (Northern, Middle, Southern and Sub-taiga) increased 15% in the moderate OSU and GISS scenarios and decreased by a third in the warmer UKMO and GFDL projections. In addition, a sensitivity analysis found that the percentage of a vegetation class that is forested is a major factor determining phytomass distribution. From 25 to 50% more phytomass is predicted under climate change if the forested proportion corresponding to potential rather than current vegetation is assumed.

• Monserud, E-mail: rm@mm.unknown
• Denissenko, E-mail: od@mm.unknown
• Kolchugina, E-mail: tk@mm.unknown
• Tchebakova, E-mail: nt@mm.unknown

The European Pine Sawfly (Neodiprion sertifer Geoffroy) is one of the most serious defoliators of Scots pine (Pinus sylvestris L.) in northern Europe. We studied the pattern in the regional occurrence of the outbreaks of N. sertifer in Finland in years 1961-90, and made predictions about the outbreak pattern to the year 2050 after predicted winter warming. We tested whether minimum winter temperatures and forest type and soil properties could explain the observed outbreak pattern. We analysed outbreak patterns at two different spatial levels: forest board- and municipal-level.

The proportion of coniferous forests on damage-susceptible soils (dry and infertile sites) explained a significant part of the variation in outbreak frequency at small spatial scale (municipalities) but not at large spatial scale (forest boards). At the forest board level, the incidence of minimum temperatures below -36 °C (= the critical value for egg mortality) explains 33% of the variation in the outbreak pattern, and at the municipal level the incidence of cold winters was also the most significant explaining variable in northern Finland. Egg mortality due to cold winters seems to be the most parsimonious factor explaining why there have been so few N. sertifer outbreaks in northern and north-eastern Finland. We predict that climate change (increased winter temperatures) may increase the frequency of outbreaks in eastern and northern Finland in the future.

• Virtanen, E-mail: tv@mm.unknown
• Neuvonen, E-mail: sn@mm.unknown
• Niemelä, E-mail: pn@mm.unknown
• Nikula, E-mail: an@mm.unknown
• Varama, E-mail: mv@mm.unknown

Two dynamic models predicting the development of frost hardiness of Finnish Scots pine (Pinus sylvestris L.) were tested with frost hardiness data obtained from trees growing in the natural conditions of Finland and from an experiment simulating the predicted climatic warming. The input variables were temperature in the first model, and temperature and night length in the second. The model parameters were fixed on the basis of previous independent studies. The results suggested that the model which included temperature and photoperiod as input variables was more accurate than the model using temperature as the only input variable to predict the development of frost hardiness in different environmental conditions. Further requirements for developing the frost hardiness models are discussed.

• Leinonen, E-mail: il@mm.unknown
• Hänninen, E-mail: hh@mm.unknown
• Repo, E-mail: tr@mm.unknown

The effects of realistically elevated O₃ and CO₂ concentrations on the needle ultrastructure and photosynthesis of ca. 20-year-old Scots pine (Pinus sylvestris L.) saplings were studied during one growth period in open-top field chambers situated on a natural pine heath at Mekrijärvi, in eastern Finland. The experiment included six different treatments: chamberless control, filtered air, ambient air and elevated O₃, CO₂ and O₃ + CO₂. Significant increases in the size of chloroplast and starch grains were recorded in the current-year needles of the saplings exposed to elevated CO₂ These responses were especially clear in the saplings exposed to elevated O₃ + CO₂ concentrations. These treatments also delayed the winter hardening process in cells. In the shoots treated with O₃, CO₂ and combined O₃ + CO₂ the P_max was decreased on average by 50% (ambient CO₂) and 40% (700 ppm CO₂). Photosynthetic efficiency was decreased by 60% in all the treated shoots measured under ambient condition and by 30% in the CO₂ and O₃ + CO₂ treated shoots under 700 ppm. The effect of all the treatments on photosynthesis was depressive which was probably related to evident accumulation of starch in the chloroplasts of the pines treated with CO₂ and combined O₃ + CO₂. But in O₃ treated pines, which did not accumulate starch in comparison to pines subjected to ambient air conditions, some injuries may be already present in the photosynthetic machinery.

• Palomäki, E-mail: vp@mm.unknown
• Holopainen, E-mail: th@mm.unknown
• Kellomäki, E-mail: sk@mm.unknown
• Laitinen, E-mail: kl@mm.unknown

BOREAS is a four-year, regional-scale experiment to study the forested continental interior of Canada. It aims at improving our understanding of the interaction between the earths' climate system and the boreal forests at short and intermediate time scales, in order to clarify their role in global change.

During the winter, spring and summer of 1994, five field campaigns were conducted. About 85 investigation teams including nearly 300 scientists participated, including forest ecologists and ecophysiologists, atmospheric physicists, boundary-layer meteorologists, hydrologists, biochemists, atmospheric chemists and remote sensing specialists.

The findings so far have been significant in terms of their implication for global change. The boreal ecosystem, occupying roughly 17 percent of the vegetated land surface and thus an important driver of global weather and climate, absorbs much more solar energy than is assumed by operational numerical weather prediction models. Albedo measurement show that this forest absorbs nearly 91% of the sun's incident energy. Additionally, while it is known that much of the boreal ecosystems consists of forested wetlands, lakes, bogs and fens, the measurements show that the atmosphere above was extremely dry; humidity and deep boundary layer convection (3,000 m) mimicked conditions found only over deserts. Physiological measurements of the trees show that this atmospheric desiccation was a result of the forests' strong biological control limiting surface evaporation. This tight control was linked to the low soil temperature and subsequently reduced rates of photosynthesis. BOREAS measurement also focused on net ecosystem carbon exchange. Data acquired during the late spring and summer, showed the boreal forests to be a net carbon sink. However, no measurements were taken in the early spring following thaw, and in the late fall, where the balance between photosynthesis and respiration is poorly understood. During 1996 additional data will be acquired to resolve the annual carbon budget and how it might depend on interannual climate differences.

• Hall, E-mail: fh@mm.unknown
• Sellers, E-mail: ps@mm.unknown
• Williams, E-mail: dw@mm.unknown

Biogeographical patterns of the Scolytidae in Fennoscandia and Denmark, based on species incidence data from the approximately 70 km x 70 km quadrats (n = 221) used by Lekander et al. (1977), were classified to environmental variables using multivariate methods (two-way indicator species analysis, detrended correspondence analysis, canonical correspondence analysis).

The distributional patterns of scolytid species composition showed similar features to earlier presented zonations based on vegetation composition. One major difference, however, was that the region was more clearly divided in an east-west direction. Temperature variables associated with the location of the quadrat had the highest canonical coefficient values on the first axis of the CCA. Although these variables were the most important determinants of the biogeographical variation in the beetle species assemblages, annual precipitation and the distribution of Picea abies also improved the fit of the species data.

Samples with the most deviant rarity and typicality indices for the scolytid species assempblages in each quadrat were concentrated in several southern Scandinavian quadrats, in some quadrats in northern Sweden, and especially on the Swedish islands (Öland, Gotland, Gotska Sandön) in the Baltic Sea. The use of rarity indices which do not take the number of species per quadrat, also resulted high values for areas near Stockholm and Helsinki with well-known faunas. Methodological tests in which the real changes in the distribution of Ips acuminatus and I. amitinus were used as indicators showed that the currently available multivariate methods are sensitive to small faunal shifts even, and thus permit analysis of the fauna in relation to environmental changes. However, this requires more detailed monitoring of the species’ distributions over longer time spans.

Distribution of seven species (Scolytus intricatus, S. laevis, Hylurgops glabratus, Crypturgus cinereus, Pityogenes salasi, Ips typographus, and Cyleborus dispar) were predicted by logistic regression models using climatic variables. In spite of the deficiencies in the data and the environmental variables selected, the models were relatively good for several but not for all species. The potential effects of climate change on bark beetles are discussed.

The PDF includes a summary in Finnish.

• Heliövaara, E-mail: kh@mm.unknown
• Väisänen, E-mail: rv@mm.unknown
• Immonen, E-mail: ai@mm.unknown

While numerous studies have focused on analyzing various aspects of the carbon (C) budget in forests, there appears to be a lack of comprehensive assessments specifically addressing the impact of stem rot on the C budget of broadleaf tree species, especially in old-growth forests where stem rot is prevalent. One of the main challenges in accurately quantifying C losses caused by stem rot is the lack of precise data on the basic density and C content of decayed wood, which are crucial for converting decayed wood volume into biomass and C stocks. Using linear mixed-effects models, we examine the variability of wood basic density, C content, and nitrogen (N) content. Discolored and decomposed wood was collected from the stems of 136 living deciduous trees common in hemiboreal forests in Latvia. Our research indicates a noticeable reduction in the wood basic density, coupled with an increase in the N content within the stem wood throughout the decomposition process in birch (Betula spp.), European aspen (Populus tremula L.), grey alder (Alnus incana (L.) Moench), and common alder (Alnus glutinosa (L.) Gaertn.). While aspen wood showed a decreasing trend in C content as decay progressed, a pairwise comparison test revealed no significant differences in C content between discolored and decomposed wood for the studied species, unlike the findings for basic density and N content. This study emphasizes the need to account for stem rot in old-growth forest carbon budgets, especially in broadleaf species, and calls for more research on stem rot-induced carbon losses.

• Liepiņš, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia https://orcid.org/0000-0003-3030-1122 E-mail: janis.liepins@silava.lv
• Jaunslaviete, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia https://orcid.org/0009-0000-7322-2729 E-mail: ieva.jaunslaviete@silava.lv
• Liepiņš, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia https://orcid.org/0000-0002-1179-8586 E-mail: kaspars.liepins@silava.lv
• Jansone, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia https://orcid.org/0000-0003-2748-3797 E-mail: liga.jansone@silava.lv
• Matisons, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia E-mail: roberts.matisons@silava.lv
• Lazdiņš, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia https://orcid.org/0000-0002-7169-2011 E-mail: andis.lazdins@silava.lv
• Jansons, Latvian State Forest Research Institute “Silava,” Rigas Street 111, LV-2169 Salaspils, Latvia https://orcid.org/0000-0001-7981-4346 E-mail: aris.jansons@silava.lv

The information on ecological niches of the Marula tree, Sclerocarya birrea (A. Rich.) Horchst. subspecies are needed for sustainable management of this tree, considering its nutritional, economic, and ecological benefits. However, despite Tanzania being regarded as a global genetic center of diversity of S. birrea, information on the subspecies ecological niches is lacking. We aimed to model ecological niches of S. birrea subspecies in Tanzania under the current and future climates. Ecological niches under the current climate were modelled by using ecological niche models in MaxEnt using climatic, edaphic, and topographical variables, and subspecies occurrence data. The Hadley Climate Center and National Center for Atmospheric Research's Earth System Models were used to predict ecological niches under the medium and high greenhouse gases emission scenarios for the years 2050 and 2080. Area under the curves (AUCs) were used to assess the accuracy of the models. The results show that the models were robust, with AUCs of 0.85–0.95. Annual and seasonal precipitation, elevation, and soil cation exchange capacity are the key environmental factors that define the ecological niches of the S. birrea subspecies. Ecological niches of subsp. caffra, multifoliata, and birrea are currently found in 30, 22, and 21 regions, and occupy 184 814 km², 139 918 km², and 28 446 km² of Tanzania's land area respectively, which will contract by 0.4–44% due to climate change. Currently, 31–51% of ecological niches are under Tanzania’s protected areas network. The findings are important in guiding the development of conservation and domestication strategies for the S. birrea subspecies in Tanzania.

• Munna, Department of Soil and Geological Sciences, Sokoine University of Agriculture, P.O. Box 3008, Morogoro, Tanzania https://orcid.org/0000-0001-8858-0457 E-mail: amabmunna81@gmail.com
• Amuri, Department of Soil and Geological Sciences, Sokoine University of Agriculture, P.O. Box 3008, Morogoro, Tanzania https://orcid.org/0000-0003-3092-3458 E-mail: namuri@sua.ac.tz
• Hieronimo, Department of Agricultural Engineering, Sokoine University of Agriculture, P.O. Box 3003 Morogoro, Tanzania https://orcid.org/0000-0002-4450-5073 E-mail: phmusigula@gmail.com
• Woiso, Department of Biosciences, Sokoine University of Agriculture, P.O. Box 3038 Morogoro, Tanzania E-mail: dino@sua.ac.tz

European spruce bark beetle (Ips typographus [L.]; SBB) damage has reached extreme and unprecedented levels in East Central Sweden, likely driven by increasing temperatures and severe drought due to climate change. However, SBB outbreaks have been less severe on the eastern side of the Baltic Sea, in Estonia and Finland, than in Sweden. This study investigated how precipitation, temperature sum, and droughts (hydrothermic index) have varied in land areas surrounding the Baltic Sea. We studied past meteorological observations from 1950 to 1999. We modeled the effect of climate change on precipitation and temperature using three representative concentration pathway (RCP) scenarios for greenhouse gas emissions (RCP2.6, RCP4.5, and RCP8.5) and multiple (17–23) climate models. Future climate projections (up to 2100) were made for Southeastern Estonia, Southern Finland, and East Central Sweden. Weather data showed that temperature sums had been high and droughts severe in the 2010s, particularly in East Central Sweden, where SBB outbreaks have been a more significant problem than on the eastern shores of the Baltic Sea. Future climate projections suggest that increases in temperature sum will further enhance SBB reproduction, especially in the RCP4.5 and RCP8.5 scenarios. In all climate change scenarios, drought continues to be a problem in East Central Sweden, potentially facilitating SBB outbreaks. In addition, moderate and severe droughts may become more frequent in Southeastern Estonia and Southern Finland if climate change proceeds as predicted in the RCP4.5 or RCP8.5 scenarios.

• Tikkanen, School of Forest Sciences, University of Eastern Finland, P.O. Box 111, FI-80101 Joensuu, Finland https://orcid.org/0000-0002-3875-2772 E-mail: Olli-Pekka.Tikkanen@uef.fi
• Lehtonen, Finnish Meteorological Institute, P.O. Box 503, FI-00101 Helsinki, Finland https://orcid.org/0000-0001-7317-9580 E-mail: Ilari.Lehtonen@fmi.fi

Carbon sequestration and income generation are competing objectives in modern forest management. The climate commitments of many countries depend on forests as carbon sinks which must be quantified, monitored, and projected into the future. For projections we need tools to model forest development and perform scenario analyses to assess future carbon sequestration potentials under different management regimes, the expected net present value of such regimes, and possible impacts of climate change. We propose a scenario analysis software tool (GAYA 2.0) that can assist in answering these types of questions using stand level simulations, detailed carbon flow models and an optimizer. This paper has two objectives: (1) to describe GAYA 2.0, and (2) demonstrate its potential in a case study where we analyze the forest carbon balance over a region in Norway based on national forest inventory sample plots. The tool was used to map the optimality front between the carbon benefit and net present value. We observed changes in net present value for different levels of carbon benefit as well as changes in optimal management strategies. We predicted future changes in several forest carbon pools as well as albedo and illustrated the impact of gradual increase in forest productivity (i.e., due to climate warming). Having been updated and modernized from its previous version with increased attention to forest carbon and energy fluxes, GAYA 2.0 is an effective tool that offers multiple opportunities to perform various types of scenario analyses in forest management.

• Strîmbu, Norwegian University of Life Sciences, Faculty of Environmental Sciences and Natural Resource Management, NO-1432 Ås, Norway https://orcid.org/0000-0002-0588-2036 E-mail: victor.strimbu@nmbu.no
• Eid, Norwegian University of Life Sciences, Faculty of Environmental Sciences and Natural Resource Management, NO-1432 Ås, Norway E-mail: tron.eid@nmbu.no
• Gobakken, Norwegian University of Life Sciences, Faculty of Environmental Sciences and Natural Resource Management, NO-1432 Ås, Norway https://orcid.org/0000-0001-5534-049X E-mail: terje.gobakken@nmbu.no

The natural northern distribution limit for pedunculate oak (Quercus robur L.) is in southern Finland. We hypothesized that the maximum frost hardiness (FH_max) in the winter limited the cultivation of oaks in northern latitudes. We tested the hypothesis with controlled freezing tests in midwinter. The acorns for the experiment were collected from the four main oak populations in southernmost Finland. The seedlings were raised in the nursery, frost hardened in field conditions, and then moved to a growth chamber at –2 °C on two occasions in winter and tested for FH_max in controlled freezing tests. Frost hardiness was assessed by differential thermal analysis (DTA) based on the low temperature exotherm (LTE) and relative electrolyte leakage (REL) of the stem, and visual damage scoring (VD) of the buds and stem. The initiation and peak of the LTE took place at an average of –41 °C and –43 °C respectively, without differences among the populations. The variation in the initiation and peak of the LTE was high, ranging from –34.6 °C to –45.5 °C and from –37.1 °C to –46.9 °C respectively. According to the REL method, the frost hardiness of the populations ranged from –44.0 °C to –46.4 °C in February and from –40.6 °C to –41.6 °C in March, without significant differences among the populations. According to VD, the bud was the least frost hardy organ, with FH between –19 °C and –33 °C, depending on population and assessment time. We conclude that the maximum hardiness may set the limit for the distribution of pedunculate oak northwards, but the high within-population variation offers potential to breed more frost hardy genotypes.

• Repo, Natural Resources Institute Finland (Luke), Natural Resources, Yliopistokatu 6b, FI-80100 Joensuu, Finland https://orcid.org/0000-0002-7443-6275 E-mail: tapani.repo@luke.fi
• Volanen, Kalevankatu 4b B21, FI-80110 Joensuu, Finland E-mail: virva.volanen@siunsote.fi
• Pulkkinen, Natural Resources Institute Finland (Luke), Production systems, Latokartanonkaari 9, FI-00790 Helsinki, Finland https://orcid.org/0000-0002-1643-7691 E-mail: pertti.pulkkinen@luke.fi

In the forest areas of eastern China, there is a change from forest dominated by deciduous broad-leaved trees to forest dominated by evergreen broad-leaved trees as the latitude or altitude decreases. Different life forms have different survival strategies to deal with climate change, and studying the life form dynamics of the tree layers in the mixed forest in eastern China, with increasing temperature, can help us understand how the forest responds. This study was performed in a 1 ha plot in evergreen and deciduous broad-leaved mixed forest in Tianmu Mountain National Nature Reserve. Based on the data from two surveys (1996 and 2017), the changes in life form composition and biodiversity over the past 21 years were analyzed. We obtained the following results: (1) The proportion of evergreen trees increased from 55.0% in 1996 to 67.5% in 2017, and the dominance of evergreen species was enhanced. (2) The diversity of both life forms increased, and the tree species were more abundant. (3) The average annual recruitment rate of the evergreen species was 2.1% greater than their mortality rate, and the average annual recruitment rate of the deciduous species was 0.5% less than their mortality rate. (4) The competition among the trees in the small-diameter class (10 cm ≤ DBH < 20 cm) was fierce for many tree species. The proportion of the evergreen species in the small-diameter class was high. The life forms making up the mixed climax forest community has changed over the past 21 years, with the proportion and dominance of evergreen trees increasing significantly.

• Bai, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: baicheng111@gmail.com
• You, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310011, China E-mail: sxyou@zju.edu.cn
• Ku, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: 2732684475@qq.com
• Dai, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: 757692949@qq.com
• Wang, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: 237600341@qq.com
• Zhao, Management Bureau of Tianmu Mountain National Nature Reserve, Hangzhou 311311, China E-mail: 973659738@qq.com
• Yu, State Key Laboratory of Subtropical Silviculture, Zhejiang A&F University, Hangzhou 311300, China E-mail: yushq@zafu.edu.cn

Phenology can have a profound effect on growth and climatic adaptability of long-lived, northern tree species such as Scots pine (Pinus sylvestris L.), where the onset of growth in the spring is triggered mainly by accumulated heat, while cessation of growth is related to the joint effect of photoperiod and temperature. In this study, the objectives were: (1) to compare shoot phenology of genetic material from Scandinavia (maritime climate origin) and northern Russia (continental climate origin) sources, under field conditions in both Scandinavia and Russia (maritime and continental growth conditions); and (2) to estimate the heritabilities of phenological parameters. The material used was part of a larger provenance test series involving Scots pine populations and open-pollinated plus-tree families from Russia, Sweden and Finland. Terminal shoot elongation was measured on multiple occasions during the seventh growing season from seed at a trial near Bäcksjön (Sweden) and Syktyvkar (northern Russia). We calculated the regression of relative shoot elongation over accumulated heat sum above +5 °C using an exponential expression. Seedlings of Swedish and Russian provenance had similar heat-sum requirements for growth onset and cessation in both trials. More northern provenances started onset and cessation at a lower temperature sum, but heat accumulation requirements for onset were not fixed. Scots pine may suffer from spring frost due to earlier growth onset in a warming climate. Variation and heritability of phenological traits show potential to adapt Scots pine to new climate conditions by breeding.

• Andersson Gull, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden https://orcid.org/0000-0003-3556-3172 E-mail: bengt.anderssongull@skogforsk.se
• Persson, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden E-mail: torgny.persson@skogforsk.se
• Fedorkov, The Institute of Biology of Komi Scientific Centre of the Ural Branch of the Russian Academy of Sciences (IB Komi SC UB RAS), Kommunisticheskaya St., 28, Syktyvkar, 167982, Russia https://orcid.org/0000-0001-7800-7534 E-mail: fedorkov@ib.komisc.ru
• Mullin, The Swedish Forestry Research Institute (Skogforsk), Box 3, SE-918 21 Sävar, Sweden https://orcid.org/0000-0003-4924-1836 E-mail: tim.mullin@skogforsk.se

The mean temperature during the potential growing season (April–September) may increase by 1 °C by 2030, and by 4 °C, or even more, by 2100, accompanied by an increase in atmospheric CO₂ concentrations of 536–807 ppm, compared to the current climate of 1981–2010, in which atmospheric CO₂ is at about 350 ppm. This may affect both the growth and frost hardiness of boreal trees. In this work, we studied the responses of height and autumn frost hardiness development in 22 half-sib genotypes of one-year-old Norway spruce (Picea abies (L.) Karst.) seedlings to elevated temperatures and atmospheric CO₂ concentration under greenhouse conditions. The three climate treatments used were: T+1 °C above ambient and ambient CO₂; T+4 °C above ambient and ambient CO₂; and T+4 °C above ambient and elevated CO₂ (700 ppm). The height growth rate and final height were both higher under T+4 °C compared to T+1 °C. Temperature increase also delayed the onset, and shortened the duration, of autumn frost hardiness development. Elevated CO₂ did not affect the development of height or frost hardiness, when compared to the results without CO₂ elevation under the same temperature treatment. Higher temperatures resulted in greater variation in height and frost hardiness development among genotypes. Three genotypes with different genetic backgrounds showed superior height growth, regardless of climate treatment; however, none showed a superior development of autumn frost hardiness. In future studies, clonal or full-sib genetic material should be used to study the details of autumn frost hardiness development among different genotypes.

• Levkoev, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: eino.levkoev@uef.fi
• Mehtätalo, University of Eastern Finland, Faculty of Science and Forestry, School of Computing, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: lauri.mehtatalo@uef.fi
• Luostarinen, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: katri.luostarinen@uef.fi
• Pulkkinen,  Natural Resources Institute Finland (Luke), Production systems, Haapastensyrjä Breeding Station, FI-16200 Läyliäinen, Finland E-mail: pertti.pulkkinen@luke.fi
• Zhigunov, Saint-Petersburg State Forest Technical University, Forestry Faculty, RU-194021, Institutskiy per. 5, Saint-Petersburg, Russia E-mail: a.zhigunov@bk.ru
• Peltola, University of Eastern Finland, Faculty of Science and Forestry, School of Forest Sciences, P.O. Box 111, FI-80101 Joensuu, Finland E-mail: heli.peltola@uef.fi

• Midmore, Forest Research Agency, Alice Holt, Surrey. Current: Dolwyddelan, Llandre, Ceredigion, Wales, SY24 5BZ E-mail: emidmore@gmail.com
• McCartan, Forest Research, Alice Holt, Farnham, Surrey, GU10 4LH, UK E-mail: shelagh.mccartan@forestry.gsi.gov.uk
• Jinks, Forest Research, Alice Holt Lodge, Farnham, Surrey, GU10 4LH, UK E-mail: richard.jinks@forestry.gsi.gov.uk
• Cahalan, Bangor University, School of Environment, Natural Resources and Geography, Bangor, Gwynedd, Wales, LL57 2UW E-mail: c.m.cahalan@bangor.ac.uk

• Düthorn, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany E-mail: duethorn@uni-mainz.de
• Schneider, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany E-mail: l.schneider@geo.uni-mainz.de
• Konter, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany E-mail: O.Konter@geo.uni-mainz.de
• Schön, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany E-mail: philipp.schoen@gmx.de
• Timonen, Natural Resources Institute Finland (Luke), Natural resources and bioproduction, FI-96301 Rovaniemi, Finland E-mail: mauri.timonen@metla.fi
• Esper, Department of Geography, Johannes Gutenberg University, Becherweg 21, 55099 Mainz, Germany E-mail: J.Esper@geo.uni-mainz.de

• Tullus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: arvo.tullus@ut.ee
• Sellin, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: arne.sellin@ut.ee
• Kupper, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: priit.kupper@ut.ee
• Lutter, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia E-mail: reimo.lutter@emu.ee
• Pärn, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia E-mail: linnar.parn@emu.ee
• Jasinska, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia & Institute of Dendrology, Polish Academy of Sciences, Parkowa 5, 62-035 Kórnik, Poland E-mail: jasiak9@wp.pl
• Alber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: meeli.alber@ut.ee
• Kukk, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: maarja.kukk@ut.ee
• Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia E-mail: tea.tullus@emu.ee
• Tullus, Institute of Forestry and Rural Engineering, Estonian University of Life Sciences, Kreutzwaldi 5, Tartu 51014, Estonia E-mail: hardi.tullus@emu.ee
• Lõhmus, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: krista.lohmus@ut.ee
• Sõber, Department of Botany, Institute of Ecology and Earth Sciences, Faculty of Science and Technology, University of Tartu, Lai 40, Tartu 51005, Estonia E-mail: anu.sober@ut.ee

• Koivuranta, Finnish Forest Research Institute, Haapastensyrjä, Finland E-mail: lk@nn.fi
• Latva-Karjanmaa, Finnish Forest Research Institute, Haapastensyrjä, Finland E-mail: tlk@nn.fi
• Pulkkinen, Finnish Forest Research Institute, Haapastensyrjä, Finland E-mail: pertti.pulkkinen@metla.fi

• Hou, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China E-mail: yh@nn.cn
• Qu, Department of Life Sciences, Shangqiu Normal University, Shangqiu, China E-mail: jq@nn.cn
• Luo, School of Environment and Life Sciences, Kaili University, Kaili, China E-mail: zl@nn.cn
• Zhang, Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: cz@nn.cn
• Wang, Shanghai Key Laboratory of Urbanization and Ecological Restoration, East China Normal University, Shanghai, China, and University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: kywang@re.ecnu.edu.cn

• Gregow, Finnish Meteorological Institute, Helsinki, Finland E-mail: hilppa.gregow@fmi.fi
• Peltola, University of Eastern Finland, Faculty of Forest Sciences, Joensuu, Finland E-mail: heli.peltola@uef.fi
• Laapas, Finnish Meteorological Institute, Helsinki, Finland E-mail: ml@nn.fi
• Saku, Finnish Meteorological Institute, Helsinki, Finland E-mail: ss@nn.fi
• Venäläinen, Finnish Meteorological Institute, Helsinki, Finland E-mail: av@nn.fi

• Kellomäki, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: seppo.kellomaki@uef.fi
• Maajärvi, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: mm@nn.fi
• Strandman, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: hs@nn.fi
• Kilpeläinen, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: ak@nn.fi
• Peltola, University of Eastern Finland, School of Forest Sciences, Joensuu, Finland E-mail: hp@nn.fi

• Seidl, Institute of Silviculture, BOKU, Vienna, Austria E-mail: rupert.seidl@boku.ac.at
• Rammer, Institute of Silviculture, BOKU, Vienna, Austria E-mail: wr@nn.at
• Lasch, Potsdam Institute for Climate Impact Research e.V., Potsdam, Germany E-mail: pl@nn.de
• Badeck, Potsdam Institute for Climate Impact Research e.V., Potsdam, Germany E-mail: fwb@nn.de
• Lexer, Institute of Silviculture, BOKU, Vienna, Austria E-mail: mjl@nn.at

• Laturi, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jani.laturi@metla.fi
• Mikkola, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: jm@nn.fi
• Uusivuori, Finnish Forest Research Institute, Vantaa Research Unit, P.O. Box 18, FI-01301 Vantaa, Finland E-mail: ju@nn.fi

• Kozlov, Section of Ecology, University of Turku, 20014 Turku, Finland E-mail: mikoz@utu.fi
• Niemelä, Forestry Faculty, University of Joensuu, P.O. Box 111, 80101 Joensuu, Finland E-mail: pn@nn.fi

• Lexer, Institute of Silviculture, University of Agricultural Sciences, Peter-Jordanstrasse 70, A-1190 Vienna, Austria E-mail: lexer@edv1.boku.ac.at
• Hönninger, Institute of Silviculture, University of Agricultural Sciences, Peter-Jordanstrasse 70, A-1190 Vienna, Austria E-mail: kh@nn.at
• Scheifinger, Institute of Meteorology and Physics, University of Agricultural Sciences, Türkenschanzstrasse 18, A-1180 Vienna, Austria E-mail: hs@nn.at
• Matulla, Institute of Meteorology and Physics, University of Agricultural Sciences, Türkenschanzstrasse 18, A-1180 Vienna, Austria E-mail: cm@nn.at
• Groll, Institute of Meteorology and Physics, University of Agricultural Sciences, Türkenschanzstrasse 18, A-1180 Vienna, Austria E-mail: ng@nn.at
• Kromp-Kolb, Institute of Meteorology and Physics, University of Agricultural Sciences, Türkenschanzstrasse 18, A-1180 Vienna, Austria E-mail: hkk@nn.at

• Lindner, Potsdam Institute for Climate Impact Research, P.O. Box 60 12 03, D-14412 Potsdam, Germany E-mail: lindner@pik-potsdam.de
• Lasch, Potsdam Institute for Climate Impact Research, P.O. Box 60 12 03, D-14412 Potsdam, Germany E-mail: pl@nn.de
• Erhard, Potsdam Institute for Climate Impact Research, P.O. Box 60 12 03, D-14412 Potsdam, Germany E-mail: me@nn.de

• Oleksyn, Polish Academy of Sciences, Institute of Dendrology, Parkowa 5, PL-62-035 Kórnik, Poland; University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA E-mail: oleks001@gold.tc.umn.edu
• Tjoelker, University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA E-mail: mgt@nn.us
• Reich, University of Minnesota, Department of Forest Resources, 1530 Cleveland Ave. N., St. Paul, MN 55108, USA E-mail: pbr@nn.us

The paper first reviews the desertification/land degradation syndrome, the shortcomings of attempts to control it and the consequences of this failure, including to climate change and biodiversity. It then examines the experience gained by carbon and biodiversity offsets that helped adapting the offsetting principle to the context of land degradation, by emphasizing the restoration of the many already degraded lands on earth, as major component of the Land Degradation Neutrality (LDN) mechanism. LDN is a new voluntary and aspirational target of a Sustainable Development Goal (SDG) under the UN 2030 Agenda for Sustainable Development, aimed at neutralizing the rate of lands coming under degrading use of their productivity. This by balancing the ongoing added degradation with similar rate of restoring equivalent lands whose productivity had been already degraded. If extensively implemented, LDN would stabilize the global amount of productive land by 2030. This would increase global food security and reduce poverty of land users, thus contributing to global sustainability. This review maintains that the failure of United Nations Convention to Combat Desertification (UNCCD) to reduce desertification triggered the emergence of LDN as a mechanism for addressing land degradation globally, rather than just desertification in the drylands. LDN accepted as target of a Sustainable Development Goal also legitimized UNCCD to lead and oversee the aspired process of achieving land degradation neutral world. This paper reviews the development of the LDN concept expressed in scientific deliberations and political advocacy, throughout the five years from inception in 2011 at the UNCCD Secretariat, to early 2016. It notes the fast and increasing acceptance of LDN, expressed in the initiation of implementation already in April 2015 by an increasing number of countries, and in the growing interest and engagement of scientists and policy-makers. But the paper also express concern regarding potential misuse of the concept.

• Safriel, Hebrew University of Jerusalem, Givat Ram, Jerusalem 9190401, Israel E-mail: uriel36@gmail.com

Forests are affected by climate change in various ways. This includes abiotic factors such as droughts, but also biotic damage by pest insects. There are numerous examples from cases where pest insects have benefitted from longer growing seasons or from warmer summers. Similarly, new pest insects have been able to expand their range due to climatic conditions that have changed from hostile to tolerable. Such seems to be the case with the nun moth (Lymantria monacha), an important defoliator of coniferous trees in Europe. For centuries, the species has had massive outbreaks across Central-Europe, while it has been a rare inhabitant in Northern Europe. Recently, the nun moth population in Finland has not only expanded in range, but also grown more abundant. This research note describes the results from the first years (2018–2019) of a monitoring program that is being conducted with pheromone traps across central and southern Finland. So far, the northernmost individuals were trapped near the 64 N degrees. However, there were more southern locations where no moths were trapped. The species was present in every trapping site below the latitude of 62 N degrees. More importantly, at some sites the abundance of the nun moth suggested that local forest damage may already occur. Given the current climatic scenarios for Fennoscandia, it is likely that the nun moth populations will continue to grow, which is why systematic surveys on their abundance and range expansions will be topical.

• Melin, Natural Resources Institute Finland, Yliopistokatu 6b, FI-80100 Joensuu, Finland https://orcid.org/0000-0001-7290-9203 E-mail: markus.melin@luke.fi
• Viiri, Natural Resources Institute Finland, Yliopistokatu 6b, FI-80100 Joensuu, Finland; UPM-Kymmene Oyj, UPM Forest, Åkerlundinkatu 11 B, FI-33100 Tampere, Finland E-mail: heli.viiri@upm.com
• Tikkanen, University of Eastern Finland, School of Forest Sciences, Yliopistokatu 6, FI-80100 Joensuu, Finland E-mail: olli-pekka.tikkanen@uef.fi
• Elfving, Natural Resources Institute Finland, Yliopistokatu 6b, FI-80100 Joensuu, Finland; University of Oulu, Department of Biology, Pentti Kaiteran katu 1, FI-90014 Oulu, Finland E-mail: riku.elfving@gmail.com
• Neuvonen, University of Turku, Biodiversity Unit, Kevo Subarctic Research Institute, FI-20014 Turku, Finland E-mail: seppo.neuvonen@utu.fi

• Sun, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, No. 9, Block 4, South Renmin Road, Chengdu, China, 610041 E-mail: shouqinsun@imde.ac.cn
• Peng, Horticulture and Landscape College, Hunan Agricultural University, Furong District, Changsha, China, 410128 E-mail: keith215@126.com
• Wang, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: cookiedot@sina.cn
• Wu, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: free2001@tom.com
• Zhou, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: haitaosun@sohu.com
• Bing, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: 78186181@qq.com
• Yu, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: dongdyu@sohu.com
• Luo, Key Laboratory of Mountain Surface Processes and Ecological Regulation, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu, China E-mail: 1254157095@qq.com

Climate change is intensifying fire regimes in boreal forests, leading to ecological disruption and raising concerns about forest resilience and post-disturbance recovery. Altered fire dynamics creates novel opportunities for implementing adaptive silviculture for climate change, including assisted migration, the intentional movement and establishment of tree species or tree populations outside their current range of distribution to better match anticipated future climates. Here, we examine how the increasing frequency, severity, and spatial extent of Canadian boreal wildfires can serve as strategic windows for introducing climate-resilient tree species and genotypes. We review how fire influences the availability and suitability of post-fire sites for assisted migration, highlighting how fire-induced changes in soil abiotic and biotic properties may facilitate or hinder the establishment of relocated tree species. While fire can simplify site preparation, reduce biotic competition, and temporarily enhance soil nutrient availability, it may also degrade soil structure by consuming or altering soil organic matter and increasing soil susceptibility to erosion and disrupt essential mycorrhizal associations. We argue that assisted migration of tree species can be a proactive silvicultural tool when used in areas with regeneration failure or where future climate conditions are likely to exceed the tolerance limits of native species. Whilst scientific evidence remains limited on the regeneration success of migrated species and genotypes in post-fire environments, we argue for an integrated adaptation strategy that combines natural regeneration with targeted assisted migration interventions, guided by local site conditions, genetic considerations, and policy support, to build resilient boreal forests under changing disturbance regimes.

• Lebel Desrosiers, Laboratoire sur la science des données, Université du Québec (TÉLUQ), 5800, rue Saint-Denis, bureau 1105, Montréal, Québec H2S 3L5, Canada https://orcid.org/0009-0007-1592-8505 E-mail: simon.lebeldesrosiers@teluq.ca
• Bélanger, Laboratoire sur la science des données, Université du Québec (TÉLUQ), 5800, rue Saint-Denis, bureau 1105, Montréal, Québec H2S 3L5, Canada E-mail: nicolas.belanger@teluq.ca
• Thiffault, Centre de recherche sur les matériaux renouvelables, Université Laval, 2425 De la Terrasse St, Québec, Québec G1V 0A6, Canada https://orcid.org/0000-0001-9586-3834 E-mail: evelyne.thiffault@sbf.ulaval.ca
• Thiffault, Service canadien des forêts, Ressources naturelles Canada, 1055, rue Du P.E.P.S., C.P. 10380, Québec, Québec G1V 4C7, Canada https://orcid.org/0000-0003-2017-6890 E-mail: nelson.thiffault@canada.ca