Forestry and Peatlands Finland
Finland forestry in numbers
Finland’s land area is 31 million hectares, of which 26 million hectares (86%) is forestry land, and 20 million hectares is forest. Finland possesses 0.5% of the world’s forest resources, and 1.5% of global felling takes place in Finland (1).
Some 20 species of trees are found in Finland, but the most significant ones for forestry are pine, spruce and birch. Pure pine forests grow in fairly dry habitats, while spruce is found in more fertile locations and birch mostly in mixed forests. More than half of all forests are mixed forests (1). The south-western corner and the south coast of Finland have a narrow zone where oak, maple, ash and elm grow. Today, about one third of Finnish forests are regenerated naturally and two thirds artificially (2).
About half of the original peatland area of Finland has been drained for forestry purposes. Today, natural peatlands are no longer subjected to drainage ditching; the activities are now concentrated on maintaining previously drained areas and the forests established there (2).
Finnish forest industry is characteristically an export industry: the average share of exports in annual production is more than 70 per cent. Forest industry accounts for approximately one-third of Finland’s net export income. 5% of the world’s forest industry production takes place in Finland, and Finnish exports represent about 10% of global exports. Forestry and forest industry combined employ directly some 95,000 people, three quarters of these in forest industry (1).
Until the early 1900s, wood was mainly consumed as fuel in Finland, but today the share of fuel wood is only around 5% of the total consumption. Of the industrial wood, the chemical pulp industry used 44%, sawmills 35%, mechanical pulp industry 15%, and plywood and other industries 6% (2).
Shifts in Finland due to climate change
Climate projections suggest a displacement of climatic zones suitable for boreal forests by 150–550 km over this century. This shift is, however, faster than the estimated potential of many species to migrate (20–200 km per century) or the capability of many soils to develop a new structure. The two most important coniferous trees, Pinus sylvestris and Picea abies, are likely to invade tundra regions under warmer conditions. These changes would be accompanied by a lesser dominance of both species in southern Finland with a concurrent increase of deciduous trees (2).
Climate change is likely to have considerable direct and indirect impacts on the productivity of Finland’s forests. This is basically because the elevation of CO2 is enhancing photosynthesis under the optimal temperature and supply of nutrients and water. However, this response may be acclimatised to the CO2 elevation or regulated down in the course of years. Climate change impacts on tree growth are closely related to stomatal functions and transpiration. Elevated CO2 results in a partial closure of stomata with a consequent reduction in transpiration but temperature increase is likely to have an opposite influence. Therefore, the combined effect of these two factors on water use efficiency might be small (2).
If the species composition of trees is managed to make optimal use of the changed conditions, 60–80% of the forests in southern Finland may consist of birch (mainly Pendula) by the year 2100. Norway spruce will decline in the south, but increase in the north (2,31). The warming may also decrease the amount of Scots pine in southern Finland (2).
According to the Finnish climatic scenarios (FINADAPT) based on the A2 emission scenario the ratio of evapotranspiration to precipitation increases in southern Finland and slightly decreases in northern Finland towards the end of this century, with regionally lower and higher soil water content in the south and north respectively (31). During 2000–2030, the primary production and net carbon sequestration of Norway spruce (Picea abies) are estimated to increase in southern Finland, due to a moderate increase in temperature and atmospheric CO2. However, further elevated temperature and soil water stress reduce the primary production and net carbon sequestration of Norway spruce from 2030–2060 to 2060–2099, especially in the southernmost region. The opposite occurs in northern Finland, where estimates show that the changing climate increases the primary production and net carbon sequestration over the 100-year simulation period due to higher water availability. In Finland, Norway spruce represents, on average, approximately 40 % of the national forest resources (31).
The anticipated higher temperatures will likely lead to a substantial reduction in snow accumulation in southern Finland due to a decreased fraction of precipitation as snow and to later snowfall and earlier snowmelt, which could reduce the recharging of soil water in the spring and early summer, and thus increase the water deficit in the rooting zone (31).
Benefits in Finland from climate change
Globally, based on both satellite and ground-based data, climatic changes seemed to have a generally positive impact on forest productivity since the middle of the 20th century, when water was not limiting (28). Very likely, primary production of Finnish forests will be higher in 2100 than it is now (56).
It was estimated that the annual growth of trees would increase by over a third within a few decades. Part of this increase will be due to improved forestry, part will be caused by higher atmospheric CO2 content, higher temperatures and longer growing seasons. The enhancement of growth will be most pronounced in northern Finland. By the end of this century, nearly half of Finland’s forest resources could be located in northern Finland, whereas currently they are divided between southern and northern Finland at a ratio of about 70% and 30%, respectively (2).
Model calculations have indicated that the total annual stemwood growth of Finnish forests may increase by up to 40% in the period 1990–2100, with the main increase north of the 63rd latitude. These calculations take into account the increases of annual mean temperature and precipitation, and the growth of atmospheric CO2 concentration. Sustainable cuttings can increase by one fourth from the present level. The share of hardwood timber would increase from the current 10% up to 30%. Some studies have given more modest stemwood growth rates, 10–15% in southern Finland and 25–35% in northern Finland (2).
The felling opportunities will increase. Plants will have access to more nutrients. The seed yield of trees will improve and natural regeneration in infertile habitats in Northern Finland will become easier (2).
Future forest policy and the consequent management should also balance the increasing capacity of forests to sequestrate carbon and the potentials to increase the supply of timber into the inner markets of Europe, while sustaining wood-using industries. The possible shift of tree species composition towards increasing dominance of hardwoods may affect the wood-processing techniques and this should be considered in future investments (15).
An example of an estimate based on climate change scenarios
The possible future impact of climate change on forest growth and timber harvest has been estimated for Finland for 2070–2099 with respect to 1990. The assumptions underlying the estimates: mean temperature increase of almost 4°C in the summer and more than 6°C in the winter, annual precipitation increase by 10% in southern and up to 40% in northern Finland, mainly in winter (IPCC SRES A2 emission scenario), and atmospheric concentration of CO2 of 840 ppm at the end of simulation in 2099, and current management practices (16).
Climate change results in the largest change in growth in the northernmost part of the boreal region; i.e. any increase to a low growth rate may result in a large percentage change. Throughout northern Finland, the growth increase is several tens of percentages. In southern Finland, the increase is much less, ranging mainly from 10% to 20%. The growth rate currently prevailing in the central part of Finland may shift up to the Arctic circle. In southern Finland the growth may increase up to 12% in this century due to climate change. This is substantially less than in northern Finland, where the growth may be doubled compared to the growth under the current climate. Over the whole country, an increase of 44% was obtained, mostly effected by the large increase in the northern part of the country.
The increase in forest growth in the northern boreal region implies an increase in the potential timber harvest and carbon sequestration. The simulations showed that under southern boreal conditions the potential cutting drains may increase up to 50% by the end of this century. In the boreal forests of northern Finland, the increase is much larger (up to 170%), but there the absolute value (3 m3/ha/a) is still less than two-thirds of that in the south (5 m3/ha/a). At the same time, the duration and depth of soil frost will reduce substantially, which makes the winter-time timber harvest more difficult and reduces the overall profitability of timber harvest (17).
Vulnerabilities in Finland - Overview
Some of the anticipated effects of climate change on forestry in Finland are clear advantages. There are also negative consequences, however, or effects that are still unclear or dependent on the intensity of climate change.
The increased vulnerability of forests (and people) with respect to climate change refers to several impacts (18,27):
- Forest cover: conversion of forests to non-woody energy plantations; accelerated deforestation and forest degradation; increased use of wood for domestic energy.
- Biodiversity: alteration of plant and animal distributions; loss of biodiversity; habitat invasions by non-native species; alteration of pollination systems; changes in plant dispersal and regeneration.
- Productivity: changes in forest growth and ecosystem biomass; changes in species/site relations; changes in ecosystem nitrogen dynamics.
- Health: increased mortality due to climate stresses; decreased health and vitality of forest ecosystems due to the cumulative impacts of multiple stressors; deteriorating health of forest-dependent peoples.
- Soils and water: changes in the seasonality and intensity of precipitation, altering the flow regimes of streams; changes in the salinity of coastal forest ecosystems; increased probability of severe droughts; increased terrain instability and soil erosion due to increased precipitation and melting of permafrost; more/earlier snow melt resulting in changes in the timing of peak flow and volume in streams. The capacity of the forest ecosystem to purify water is an important service, obviating the cost of expensive filtration plants.
- Carbon cycles: alteration of forest sinks and increased CO2 emissions from forested ecosystems due to changes in forest growth and productivity.
- Tangible benefits of forests for people: changes in tree cover; changes in socio-economic resilience; changes in availability of specific forest products (timber, non-timber wood products and fuel wood, wild foods, medicines, and other non-wood forest products).
- Intangible services provided by forests: changes in the incidence of conflicts between humans and wildlife; changes in the livelihoods of forest-dependent peoples (also a tangible benefit); changes in socio-economic resilience; changes in the cultural, religious and spiritual values associated with particular forests.
For the forests in northern Europe, the combination of raised mean temperature and a higher frequency of extreme events will have negative effects that could ultimately be of greater importance than the positive outcomes of a warmer climate. The boreal forests, for example, may be severely affected by summer dry spells and droughts, making trees more susceptible to frost damage, windthrow, storms and attacks by pests and diseases (12).
The risk of nutrients leaching, and the risk of wind damage and weakened anchoring of trees to the soil as ground frost declines will increase. The combined effects of air pollutants (ozone) and UV radiation on ecosystems will become intensified due to climate change.
Potentially reduced ground frost will make forest harvesting more difficult. The extension of the thawing season will impose additional needs on machine capacity and wood storage (2).
Increased precipitation, cloudiness and rain days and the reduced duration of snow cover and soil frost may negatively affect forest work and timber logging determining lower profitability of forest production and a decrease in recreational possibilities (13).
Increased wind damages, especially in northern and western Europe, may more frequently result in an imbalance in orderly harvesting procedures with increased costs and disturb timber markets with an imbalance between the supply and demand of timber (15).
Pests and diseases
Insect pests will benefit from increased temperatures and the longer growing season. This may increase the number of insect generations each year. One such species is the spruce bark beetle, the worst pest affecting
spruce. An increase in minimum temperatures in the winter could facilitate the spread of pest species in Finland from south to north and from central Europe to southern Finland (e.g. the Gypsy and Nun moth). The risk of fungal diseases may also increase in a warmer climate (29).
In Europe, the forested areas are the main source of groundwater, and they absorb precipitation and reduce the risk of excess surface flow and floods and erosion. In this respect, the groundwater resources in northern and western Europe are in no danger as is the case in central and southern Europe. The reduction of forest cover may increase surface flow and floods. In northern Europe, the increasing precipitation may also increase the risk of floods even though the forest cover buffers watersheds (15).
Under the assumption that the wind climate will not change, the risk of windstorms for forestry between now and 2100 will increase in Finland due to an increase in the exposure of the amount of forest to windstorms (30).
Vulnerabilities - Forest damage by snow loads
Heavy snow loads may damage forests. Trees may break or bend, and they may be uprooted when the soil is unfrozen (33). Trees damaged by snow are furthermore susceptible to insect attacks and other kinds of consequential damage (34). Snow-induced forest damage occurs frequently in Northern Europe, in central Europe and in mountainous regions such as the Alps and Pyrenees (35). On the European level, estimates of the amount of timber damaged by snow during a typical year vary between one and 4 million m3 (36).
This damage may change when characteristics of winter precipitation change. It’s not just the ratio between rainfall and snow that counts, it’s also the characteristics of the snow, and hence the weight of the snow loads, that may change. With respect to forest damage, experts distinguish four different kinds of snow: rime, dry snow, wet snow and frozen snow. Accretion of heavy wet snow poses the greatest risk to forests (35). This type of snow attaches more effectively to tree crowns and branches when temperatures are close to freezing point at the time of precipitation (37). Thus, when winters get warmer in the coldest parts of Europe snow-induced forest damage may actually increase when the characteristics of the snow load changes. This effect was assessed for Finland for an intermediate and high-end scenario of climate change (the so-called RCP4.5 and RCP8.5 scenarios) by using five climate models (GCM’s) (32).
In Finland, snow damage accounts for about 7% of the total indemnities paid by insurance companies to forest owners (38). Most damage to Finnish forests is due to windstorms though: windstorms account for about 77% of forest damage in Finland compensated for by private insurance companies.
The assessment shows that the impact of climate warming varies for forests in different parts of Finland. While climate becomes warmer, the annual maximum snow loads are likely to increase in eastern and northern Finland while in the southern and western parts of the country they are expected to decrease. The risk for snow-induced forest damage is likely to increase in the future in the eastern and northern parts of Finland, i.e. in the areas experiencing the coldest winters in the country. The increase is partly due to the increase in wet snow hazards but also due to more favourable conditions for rime accumulation in a future climate that is more humid but still cold enough (32).
Vulnerabilities - Non-timber products
Increasingly there are concerns about the productivity of non-timber products such as medicines and foods. Relatively little information is available in the scientific literature about the sustainable management of such products, and even less is known about their vulnerability to climate change (18).
Vulnerabilities - Invasive species
Vanhanen (2008) reported on the impact of climate change and global trade on the spread of invasive insects in Europe. The text below is a summary of this report (3).
Definition of invasive species
Species that spread through human action into new areas, causing direct negative impact on the environment or economy are most often called invasive species or alien pests. Species that do not cause such an impact are more commonly called exotic, non-indigenous or non-native species. Though not having a direct negative impact, all of the species that inhabit a new continent may still alter the functioning of the ecosystem.
Impact of invasive species
Human induced inadvertent introductions of invasive forest insects have become a serious threat to both biodiversity and the economy, causing disturbance and direct damage to natural forests and commercial stands. The rates of forest pest invasions have increased with increased trade and travel between and within continents. There are 109 exotic phytophagous species known to have successfully invaded and established themselves on Europe’s woody plants from both North America and Asia, and more will invade as international trade continues and its volume increases.
The rate of primary production, the amount of unused resources, anthropogenic disturbance of the habitat and low species richness have been thought to be the basic principles that make some biota more prone to invasions. The invading species requires a suitable host, its native or possible congeneric and the ability to adapt to competing species, predators, parasites and pathogens in order to establish itself.
Invasive species may have an ecological impact on native species. The impact may occur on ecosystem, community, population, individual, or genetic level. Invasive species may directly exclude native species (4), change community structure (5) and function (6) or affect population genetics in the recipient community (7).
Besides their direct and indirect impacts on native ecosystems, invasive species cause immense economic losses. In the USA there are over 50,000 non-native species, and the economic losses which invasive species cost are almost $ 120 billion per year in prevention and damage control (8).
Factors governing invasion
The most prominent factors governing successful establishment are the ecological opportunities on arrival and the competitiveness of the invader. Suitable climate and available host species are the most prominent factors, but species abilities or life history traits, e.g. wide tolerance of hosts, asexuality and tolerance of population gaps, enhance the possibility of establishment. Also, the number of invading individuals, i.e. the propagule pressure, may be important in increasing the probability of establishing a viable population.
Climate change and invasive species
Seasonal climate patterns, particularly moisture and temperature, can be crucial, especially for introduced forest pathogens. To infect suitable hosts, develop a disease and survive, correct temperature (e.g. warmer winters, milder summers) and correct moisture content (e.g. fog, rainfall, less snow cover) at a critical season are the prerequisites (9).
On the whole, climate change will make biological invasions of species from southern locations more prevalent, especially by raising lethal winter temperatures. For species that are already established in Europe climate change would appear as a range shift, in the absence of extreme temperatures in winter that diminish population levels and possible shifts to novel host plants (10).
Climate-based modeling tools are also helpful in determining the potential risks posed by climate change-induced range shifts of native and exotic insect species, although they do not allow consideration of possible changes in bottom-up or top-down regulation of the populations. These factors include e.g. resource availability, diseases, parasites and predators. Nonetheless, range shifts and potential population fluctuations of forest pests to outbreak level pose a potential threat to silviculture. This threat should be considered when planning forest management practices, as many potential pest species are likely to migrate further north.
In general, management has a greater influence on wood production in Europe than climate or land-use change. Forest management is influenced more strongly by actions outside the forest sector, such as trade and policies, than from within (14).
The shortening of thermal winters deteriorates the preconditions of timber harvesting and transportation of timber in forest truck roads, since the lack of ground frost weakens ground-bearing capacity (57).
Vulnerabilities - peatlands
Peatlands cover a large portion of the land area in the Nordic countries. In Finland about 30% of the land area is covered with peat of varying thickness, in Sweden 25%, in Iceland 10% and in Norway 8%. Parts of these peatlands are being used for agriculture, often as grassland for cattle and milk production. In Finland and Sweden, for instance, organic agricultural soils cover 10% and 7% of the agricultural land area, respectively (39).
The development of new drainage techniques at the beginning of the 20th century has accelerated the exploitation of peatland area and altered patterns of use. In the Nordic countries between 3% and 40% of the original peatland area has been drained for agricultural purposes. In some regions, e.g. in Finland, more than 50% of the peatlands are drained for forestry and only 3% for agriculture. Land drainage in all the Nordic countries was largely a government driven policy to mitigate severe socio-economic risks related to emigration to USA, food security, unemployment and poverty (40).
Drainage for agriculture leads to land subsidence
Drained organic soils differ significantly from mineral soils as they subside over a relatively short time period due to compaction, shrinkage, erosion and oxidation. Cultivation in Nordic conditions leads to subsidence rates that can vary from 0.5 cm/year on fields with pasture to 2.5 cm/year on fields with row crops (41). This subsidence leads to loss of organic matter, leaching of nutrients, mineralization of carbon and nitrogen and therefore emission of greenhouse gases carbon dioxide (CO2) and nitrous oxide (N2O).
Agricultural peatlands require repeated lowering of drainage as subsidence alters the effectiveness of the original drainage system with reduced bearing capacity and lower yields. Ultimately, long-term agricultural usage of peatland depends on the possibilities to redrain the peat, and the quality of underlying substrates and its suitability for long-term agriculture (39).
Drained peatlands emit greenhouse gases
Organic soils are responsible for a significant portion of the anthropogenic CO2 and N2O emissions (42). N2O emission is particularly relevant since N2O is a 300 times more effective greenhouse gas than CO2. Drainage of peatlands changes the hydrology and microbiological processes of the peat and therefore impacts gas exchange from the peat dramatically. Greenhouse gases emissions associated with peat extraction, peatland forestry and agriculture have to be accounted for in national inventories on total emissions of greenhouse gases.
And draining peatlands has several other negative effects
Peatlands are important to mitigate regional flooding since they store water from heavy rainfall. Draining peatlands may therefore negatively impact flood protection. Also, ecosystem processes such as carbon sequestration and biodiversity are disturbed. Due to drainage, water flows more vertically through the topsoil layer leaching out nutrients, dissolved organic carbon, and in some cases metals (43).
Properties to be improved in the future include, among others, adaptation to increased mean temperature and an extended growing season, as well as resistance to pests (2).
A well-managed forest creates preconditions for adaptation to climate change. Natural and artificial regeneration both have their advantages in terms of adaptation to climate change. Natural regeneration creates opportunities for utilising the natural genetic potential of the tree species for adaptation to climate change. On the other hand, selection of the origin of artificial regeneration material and the use of improved material will allow a more efficient response to climate change. If the intention is to favour coniferous trees over others, artificial regeneration must be increased (2).
A shorter rotation of forest and regular forest management will improve adaptation by accelerating the spreading of new, genetically better adapted populations and reducing the risk of pest damage. In the field of forestry, additional research on ecosystem functions is needed in order to develop methods for forest management that are more adaptive to climate change (2).
Adaptation to invasive species (3)
Recognition of potential invaders and their major pathways helps to prevent or reduce introductions, since not all of the imported exotic insects are invasive, nor do they manage to establish themselves in novel environments. The risk of establishment is most severe where the main host species for the potential invader occurs naturally or is widely cultivated.
Efforts to prevent the introduction of invasive species include quarantine regulations, inspections of imported goods and actions based on risk analysis, which are usually made for high risk species.
Risk analysis is usually based on potential pathways and vectors. It estimates the likelihood of the invader to establishing itself and becoming invasive according to biogeographical (climate, habitat, hosts) suitability. Also, the consequences and economic losses after establishment are sometimes estimated in risk assessment. This knowledge will further be valuable when forming management strategies and policies to prevent invasions or to suppress damage by invaders.
Provided the climatic requirements are met, the invading species requires a suitable host for successful establishment. Host availability estimation is crucial when herbivorous insects are considered, and therefore palatability tests are conducted or estimates are made of suitable hosts for the most invasive pests (11). The availability of native hosts and the palatability of congeneric species in the recipient region are determinants of the species’ potential to establish itself and invade a region. Possible relationships between native predators, parasites and potential competing species are difficult to estimate and they are often neglected in risk assessments.
The European and Mediterranean Plant Protection Organization (EPPO) is an intergovernmental organization that coordinates European plant health and phytosanitary issues. Its approach is to develop international strategies for preventing the introduction of plant pests and diseases and to search for efficient control methods.
Adaptation strategies - Forest management measures in general
The establishment of migration corridors from south to north between fragmented landscapes is reported as a means of aiding the migration of species responding to changed climatic conditions. Changing the species composition to form more stable forests is reported as a management option; an example is changing the species in southern Finland from spruce and pine to birch. In a similar context, Sweden has been working on a breeding programme aimed at developing trees that would be adapted to the projected future climate (19).
To adapt to shorter winter harvesting periods as well as soft soils and roads, new harvesting techniques that better suit new conditions need to be developed. It is also reported that in some regions increasing population levels of large game, in particular moose, will increase the need for game management (19).
Future forest management should carefully consider the region-specific conditions of sites and adaptive practices to climate change for maintained or enhanced forest production and carbon sequestration. In southern Finland, wider spacing, shorter return periods between thinning, and a shift to more drought-tolerant ecotypes are ways to adapt the forest to more frequent droughts due to climate change (31).
Replacement of needle-leaved tree species by broad-leaved species
The boreal forest is experiencing higher rates of warming than any other forested region on the planet (50). Boreal forest fires not only impact greenhouse gas emissions, they also impact human health and safety, damage physical infrastructure, and result in losses of industrial timber. For instance, the 2010 wildfires around Moscow (Russia) were linked to roughly 11,000 deaths through their effect on air pollution (51). The 2016 Fort McMurray fire in Canada resulted in estimated losses of CAD$4.6 billion (49).
In 2015, needle-leaved forests represented 54% of the boreal biome. It is argued that increasing the broad-leaved tree composition is an effective way to adapt to the increased regional fire risk from climate change (49). Because of their higher leaf moisture content and lower flammability, broad-leaved tree species are less likely to burn than needle-leaved (52). Pure broad-leaved stands are about 24 times less likely to burn in a stand-replacing event than pure needle-leaf stands (53). Reducing the risk of wildfires (with regards to both frequency and spread) in boreal biomes through increased broad-leaved tree composition is therefore a means to reduce greenhouse gas emissions (49). Because of the higher year-round albedos of deciduous broad-leaved forests compared to evergreen needle-leaved forests, the earth would absorb less solar energy, thus having a cooling effect throughout the boreal zone (54).
A shift from mature needle-leaved to mature broad-leaved forest can reduce the fire risk between three to five times for many boreal forest regions (53). This shift can be made as part of regular management activities in actively managed forests. In southern Canada, for instance, converting just 0.1-0.2% of forested area per year, starting in 2020, may even be sufficient to mitigate the expected increase in fires due to climate change, scientists state (55).
The terms adaptation and adaptive management are often incorrectly used interchangeably. The former involves making adjustments in response to or in anticipation of climate change whereas the latter describes a management system that may be considered, in itself, to be an adaptation tactic (21). Adaptive management is a systematic process for continually improving management policies and practices by learning from the outcomes of operational programmes (22). It involves recognizing uncertainty and establishing methodologies to test hypotheses concerning those uncertainties; it uses management as a tool not only to change the system but to learn about the system (23).
Both the climate and forest ecosystems are constantly changing, and managers will need to adapt their strategies as the climate evolves over the long term. An option that might be appropriate today given expected changes over the next 20 years may no longer be appropriate in 20 years’ time. This will require a continuous programme of actions, monitoring and evaluation – the adaptive management approach described above (20).
There is a widespread assumption that the forest currently at a site is adapted to the current conditions, but this ignores the extent to which the climate has changed over the past 200–300 years, and the lag effects that occur in forests. As a result, replacement of a forest by one of the same composition may no longer be a suitable strategy (20).
Adaptation to climate change has started to be incorporated into all levels of governance, from forest management to international forest policy. Often these policies are not adopted solely in response to climate, and may occur in the absence of knowledge about longer-term climate change. They often serve more than one purpose, including food and fuel provision, shelter and minimizing erosion, as well as adapting to changing climatic conditions (19).
Socio-economic and political conditions have significant influences on vulnerability and adaptive capacity. Climate change projections are perceived by many forest managers as too uncertain to support long-term and potentially costly decisions that may be difficult to reverse. Similarly, uncertainty over future policy developments may also constrain action. Finance is a further barrier to implementing adaptation actions in the forest sector (24).
Any community currently dependent on forestry is at risk of destabilization, some more seriously than others. There is likely to be a high level of variation in the ability of forest-dependent communities to adapt to climate change, but there have been relatively few rigorous studies investigating this. One study in northern Europe revealed that the communities in Norrbotten (Sweden), Lappi (Finland) and Arkhangelsk oblast (Russia) differed markedly, primarily because of their varying degrees of dependence on natural resources and their ability to counteract negative effects (25). The greater the diversification of a local economy, the less its vulnerability to climate change is likely to be because of its ‘room for maneuver’ (26).
A country’s ability to adapt to climate change will depend largely on financial, human and institutional capacities; thus the more developed regions may adapt more easily than regions within less developed countries. As the boreal domain consists of comparatively few countries with well- developed economies, there are good grounds for adaptation (19).
Adaptation peatlands: how to stop subsidence and greenhouse gases emissions?
The negative consequences of using peatlands for agriculture as summarized above raise a few pressing questions. Should farming continue on peat soils? Can management choices reduce negative impacts? What alternatives exist and what are their socio-economic and environmental consequences? These questions were addresses in a recent review (39).
Afforestation is not the solution
Some say afforestation of drained peatlands, especially croplands, reduce the overall emissions of greenhouse gases. Indeed, CO2 emission of afforested former croplands can be lower than in arable croplands, although the effect depends strongly on the climatic conditions (44,45). In most cases, however, this is not true for the N2O emissions; these emissions can remain high for decades (46).
One solution: continue cultivation as long as this is profitable
According to the authors of this review there is little or no scientific evidence that changing cultivation methods or growing specific crops can reduce the emission of greenhouse gases. They recommend, therefore, that the sites that are cultivated should continue the cultivation as long as this is profitable. Crops should be managed in such a way as to ensure a maximum return for each CO2 equivalent emitted, they state, and this could be achieved by maintaining biomass levels as high as possible (39).
After cultivation, forestry or biocrops can be an option as an alternative land use, if the soil and drainage is suitable for such vegetation. Forestry or biocrops will not stop CO2 emission from the peatsoils and high N2O emissions may remain, but carbon will be sequestered. Some bioenergy crops can be productive even with a high water table level. For fields too wet to cultivate with agricultural crops, these bioenergy crops could prolong the life of the area as a productive field with the ability to sequester carbon in the biomass. Harvesting these crops on wet soils remains a challenge, however (39).
Another solution: change in land use
Rewetting has been recommended as a practice to protect organic material in former cultivated land from further mineralization by excluding oxygen, and thereby reducing the emission of greenhouse gases (47). It has also been proposed as a method to increase biodiversity. Rewetting must be accompanied by moisture tolerant crops (paludiculture) if one aims to continue agricultural use.
While the goal of rewetting often is to encourage the return of peat forming plants and the ecosystem services they provide such as carbon sequestration, it is not well known if these plants will grow on peat soils that have been altered by the process of drainage and management. Peat extraction followed by rewetting might provide a sustainable option as rewetting is often easier if the nutrient rich topsoil peat is removed, starting the peat accumulation from scratch. Also this provides a way to finance the after-use (39).
In the short term (0-5 years) rewetting can lead to a net increase in the emission of greenhouse gases because stopping drainage may lead to a high but fluctuating water table. A highly fluctuating water table can lead to an increase in CH4 emissions due to submersion of the active rooting layer leading to anoxic mineralization of labile carbon combined with a reduction in CH4 oxidation. In contrast, drained organic soils are only minor sources or even sinks for methane (CH4) (45). Thus it is important to ensure a high and relatively stable water table when drained organic soils are rewetted. Research in the Netherlands has shown that rewetting can restore the carbon sink function of managed peatlands after 15 years (48).
The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for Finland.
- Marttila et al.(2005)
- Ministry of the Environment of Finland (2006)
- Vanhanen (2008)
- Goulson (2003), in: Vanhanen (2008)
- Liebhold et al. (1995), in: Vanhanen (2008)
- Lovet et al. (2002), in: Vanhanen (2008)
- Hänfling and Kollmann (2002), in: Vanhanen (2008)
- Pimental et al. (2004), in: Vanhanen (2008)
- Marosy et al. (1989), in: Vanhanen (2008)
- Liebhold et al. (1995); Ayres and Lombardero (2000); Volney and Fleming (2000); Battisti (2004); Veteli et al. (2005); Battisti et al. (2006); Stastny et al. (2006), all in: Vanhanen (2008)
- MacFarlane and Meyer (2005); MacLeod (2002), both in: Vanhanen (2008)
- MICE (2005), in: Behrens et al. (2010)
- Maracchi et al. (2005)
- Schröter et al. (2005)
- Kellomäki et al. (2000)
- Ruosteenoja et al. (2005), in: Fischlin (ed.), 2009
- Venäläinen et al. (2001), in: Fischlin (ed.), 2009
- Innes (ed.) (2009)
- Roberts (ed.) (2009)
- Innes (ed.) (2009)
- Ogden and Innes (2007), in: Innes (ed.) (2009)
- BCMOF (2006a), in: Innes (ed.) (2009)
- Holling (1978); Lee (1993, 2001), all in: Innes (ed.) (2009)
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