Forestry in numbers

Forests surface area in France increased by more than 507,000 hectares between 1992 and 2000. Forests occupy 27.3% of the country and 2.2% is occupied by wooded areas (poplar groves, copses and scattered trees). French forests are very diverse, reflecting the diversity of the biogeographic conditions in the country. Thus, at least fifteen species have to be included to cover 90% of the forest area. Broad-leaved trees are dominant, occupying more than 63% of the wooded area. Resinous trees and mixed forest respectively occupy 27% and 9% of wooded land (1).

Forest management is oriented towards a  number of objectives, pulp-, saw-, and ply-wood production for intensively managed forests or soil fixation for littoral and mountain forests, or recreation forests (2).

Vulnerabilities - France

Forestry

The impact of climate change on forest productivity will occur over two timescales (31):

In the short term (up to 2030 or 2050, depending on the scenario), the impact of gradual climate changes on wood production will be more or less positive, with economic gains that could reach EUR 150 million per year. These gains will be significant from the Massif Central to the northeast quarter of France, where the number of freezing days will decrease sharply, parallel to an increase in average temperature. Nevertheless, extreme events such as droughts, heatwaves and fires could strongly mitigate the positive effects on a national level.

In the long term (up to 2100), because of more frequent extreme events and the spread of the Mediterranean forest, the effects will be clearly negative.

A decline in the level of water stored in soils during the summer vegetation season would lead to considerable deterioration and losses in production for the farming and forestry sectors, particularly in the South. These losses would not be entirely offset by the “fertilising” effect of the increase in CO2. For instance, the intensive growing of corn and maritime pines in the Landes region (south-western coast) could be threatened, while the Mediterranean forest could be severely damaged by bouts of intensified drought and more frequent forest fires (1).

Dendroclimatic studies (focusing on the relationship between climate and land cover) show that beech forests in the plains, and at average altitude in the Lorraine region are also particularly sensitive to hydric stress, as are the Scots pines and Aleppo pines that grow in certain parts of the southern Alps. The deterioration of the forests due to drought could be worsened by infestation by insects or pathogenic fungal species (elm bark beetles, armillaria, etc.) (1).

It is unlikely that climate changes could dramatically affect forest regeneration during the period under consideration (2000-2050) even if flowering, pollen and seed production and seed maturation could be locally affected. Due to the uncertainty in climate scenarios, the extent to which the positive impact of the CO2 increase will counteract the negative impact of reduced summer precipitation remains an open question. Most vulnerable are drier areas and forests growing an shallow soil with little prospect for potential increase in soil water reserves and nutrient supplies will be more affected (2).

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 (2).

Peatlands

Peatlands cover 3–4% of the earth surface. Their extent is tending to decrease worldwide: 6% over the period 1993–2007, according to estimates (33). They are important potential sources of CO2; this may be released due to organic matter mineralization when the oxygen concentration in peat increases due to water drawdown (34). Decreasing groundwater levels can also cause land subsidence, due to the reorganization of the peat structure (35).

The impact of groundwater exploitation and climate change was assessed on the extension of peatlands in the Cotentin marshes (Normandy, Northwest France) (32). The hydrology of the peat layer and extent of this peat area are impacted by drainage for agriculture, groundwater abstractions in underlying aquifers and climate change. Climate change scenarios were downscaled from 14 GCMs corresponding to the A1B greenhouse gas (GHG) scenario over the periods 1961–2000 and 2081–2100. Results show that climate change is expected to have an important impact and may reduce the surface of wetlands by 5.3–13.6% between these two time periods. In comparison, the impact of groundwater abstraction (100% increase in the expected scenarios) would lead to a maximum decrease of 3.7%. Results also show that the impacts of climate change and groundwater abstraction could be partially mitigated by decreasing or stopping land drainage in specific parts of the area.

Vulnerabilities - Overview

The increased vulnerability of forests (and people) with respect to climate change refers to several impacts (23,29):

• 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.

Productivity

Increasing CO2 concentration can affect tree growth through increased photosynthetic rates and through improved water-use efficiency. There will be complex interactions, however: forest growth rates may well be increased in some cases by rising levels of atmospheric CO2, but rising temperatures, higher evaporation rates and lower rainfall may lower growth rates in other cases (14).

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 (23).

Vulnerabilities – Temperate forests in Europe

Present situation

In parts of Europe with temperate forests, annual mean temperatures are below 17°C but above 6°C, and annual precipitation is at least 500 mm and there is a markedly cool winter period (3). Temperate forests are dominated by broad-leaf species with smaller amounts of evergreen broad-leaf and needle-leaf species (4). Common species include the oaks, eucalypts, acacias, beeches, pines, and birches.

Many of the major factors that influence these forests are due to human activities, including land-use and landscape fragmentation, pollution, soil nutrients and chemistry, fire suppression, alteration to herbivore populations, species loss, alien invasive species, and now climate change (5).

Forest productivity has been increasing in western Europe (6). This is thought to be from increasing CO2 in the atmosphere (7), anthropogenic nitrogen deposition (8), warming temperatures (9), and associated longer growing seasons (10).

Trends

Most models predict continuing trends of modestly increasing forest productivity in Western Europe over this century (11). Projections for the time near the end of the next century generally suggest decreasing growth and a reduction in primary productivity enhancement as temperatures warm, CO2 saturation is reached for photosynthetic enhancement, and reduced summer precipitation all interact to decrease temperate zone primary productivity (12). The projected increased occurrence of pests, particularly in drought-stressed regions, also contributes to decreased long-term primary productivity in some regions of temperate forests  (13).

Sensitivity to increasing air pollution loads, particularly nitrogen deposition and tropospheric ozone, will impact large areas of the northern temperate forest over the next century. In the temperate domain, air pollution is expected to interact with climate change; while the fertilization effects from nitrogen deposition are still highly uncertain, pollutants such as ozone are known to diminish primary productivity (14).

Migration

The ranges of northern temperate forests are predicted to extend into the boreal forest range in the north and upward on mountains (15). The distribution of temperate broadleaved tree species is typically limited by low winter temperatures (16). Since the latter are projected to rise more rapidly than summer temperatures in Europe and North America, temperate broad-leaved tree species may profit and invade currently boreal areas more rapidly than other temperate species.

Carbon sinks/sources

Temperate forest regions in the highly productive forests of western Europe (17) are known to be robust carbon sinks, although increased temperature may reduce this effect through loss of carbon from soils (18). Weaker carbon sinks or even carbon losses are seen for temperate forests in areas prone to periodic drought, such as southern Europe (19).

Models suggest that the greatest climate change threat to temperate forest ecosystems is reduced summer precipitation, leading to increased frequency and severity of drought (20). This will probably be most prominent in temperate forest regions that have already been characterized as prone to drought stress, such as southern Europe. Drought-stricken forests are also more susceptible to opportunistic pests and fire (21). Together, these related effects can potentially change large areas of temperate forest ecosystems from carbon sinks to sources.

Benefits

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 (30).

Timber production in Europe

Climate change will probably increase timber production and reduce prices for wood products in Europe. For 2000–2050 a change of timber production in Europe is expected of -4 to +5%. For 2050–2100 an increase is expected of +2 to +13% (22).

Adaptation strategies

In the national strategy of France the following adaptation measures are recommended (31):

Forestry management:

• Harvest more: measures for harvesting more and keeping a “reasonable” forest stock
• Lower the age of use/rotation
• Choose suitable species
• Diversify populations
• Encourage species migration by regeneration management in synergy with the migration corridors
• Manage additional volumes resulting from hazards
• Develop new forest management methods to protect against natural hazards in order to ensure the permanence of afforestation and its production.
• Strengthen the measures aimed at reducing other aggressions towards weakened forest ecosystems.

Research, observation:

• Work on species robustness/resistance
• Develop a system for monitoring the impacts of climate change

Land use planning:

• Shape the management of protected forest areas
• Have the territories specialise

Industry, outlets:

• Adapt the industry to wood that can be produced by the forests of tomorrow
• Develop standards and apply measures aimed at encouraging the use of wood (particularly in construction)

It should be noted that some of the measures intended for forests might also limit storm-inflicted damage. Monitoring of the condition of our forests will have to be reinforced (1).

Regarding prairie land and bovine-meat breeding in the Massif Central region, simulations show an increase in average annual grass production of approximately 20% (not taking into effect the risk of dry spells) and modifications in the quality of fodder. This might lead breeders to convert temporary pastures into permanent pastures, thereby increasing the storage of carbon in the soil (1).

Management of drier forests may aim at keeping the stand water use under an upper limit using thinning and understorey control for managing the stand, and lowering the root limit by deep ploughing. The forest requirements in water should also be taken into account in the regional plans of water resource management (2).

Adaptation strategies - Forest management measures in general

Near-nature forest management and a move away from monocultures toward mixed forest types, in terms of both species and age classes, are advocated. In addition, natural or imitated natural regeneration is indicated as a method of maintaining genetic diversity, and subsequently reducing vulnerability. For management against extreme disturbances, improvements in fire detection and suppression techniques are recommended, as well as methods for combating pests and diseases. It is reported that through stricter quarantine and sanitary management, the impact of insects and diseases can be minimized. The establishment of migration corridors between forest reserves may aid in the autonomous colonization and migration of species in response to climate change (27).

Adaptive management

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 (24). Adaptive management is a systematic process for continually improving management policies and practices by learning from the outcomes of operational programmes (25). 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 (26).

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 (23).

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 (23).

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 (27).

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 (28).

References

The references below are cited in full in a separate map 'References'. Please click here if you are looking for the full references for France.

1. République Française (2001)
2. Kellomäki et al. (2000)
3. Walter (1979), in: Fischlin (ed.) (2009)
4. Melillo et al. (1993), in: Fischlin (ed.) (2009)
5. Reich and Frelich (2002), in: Fischlin (ed.) (2009)
6. Carrer and Urbinati (2006), in: Fischlin (ed.) (2009)
7. Field et al. (2007b), in: Fischlin (ed.) (2009)
8. Hyvönen et al. (2007); Magnani et al. (2007), both in: Fischlin (ed.) (2009)
9. Marshall et al. (2008), in: Fischlin (ed.) (2009)
10. Chmielewski and Rötzer (2001); Parmesan (2006), both in: Fischlin (ed.) (2009)
11. Alcamo et al. (2007); Field et al. (2007b); Alo and Wang (2008), all in: Fischlin (ed.) (2009)
12. Lucht et al. (2006); Scholze et al. (2006); Alo and Wang (2008), all in: Fischlin (ed.) (2009)
13. Williams et al. (2000); Williams and Liebhold (2002); Logan and Powell (2001); Tran et al. (2007); Friedenberg et al. (2008), all in: Fischlin (ed.) (2009)
14. Fischlin (ed.) (2009)
15. Iverson and Prasad (2001); Ohlemüller et al. (2006); Fischlin et al. (2007); Golubyatnikov and Denisenko (2007), all in: Fischlin (ed.) (2009)
16. Perry et al. (2008), in: Fischlin (ed.) (2009)
17. Liski et al. (2002), in: Fischlin (ed.) (2009)
18. Piao et al. (2008), in: Fischlin (ed.) (2009)
19. Morales et al. (2007), in: Fischlin (ed.) (2009)
20. Christensen et al. (2007); Fischlin et al. (2007); Meehl et al. (2007); Schneider et al. (2007), all in: Fischlin (ed.) (2009)
21. Hanson and Weltzin (2000), in: Fischlin (ed.) (2009)
22. Karjalainen et al. (2003); Nabuurs et al. (2002); Perez-Garcia et al. (2002); Sohngen et al. (2001), in: Osman-Elasha and Parrotta (2009)
23. Innes (ed.) (2009)
24. Ogden and Innes (2007), in: Innes (ed.) (2009)
25. BCMOF (2006a), in: Innes (ed.) (2009)
26. Holling (1978); Lee (1993, 2001), all in: Innes (ed.) (2009)
27. Roberts (ed.) (2009)
28. Keskitalo (2008), in: Roberts (ed.) (2009)
29. Kirilenko and Sedjo (2007)
30. Boisvenue et al. (2006)
31. ONERC (2007/2009)
32. Armandine Les Landes et al. (2014)
33. Prigent et al. (2012), in: Armandine Les Landes et al. (2014)
34. Holden et al. (2004), in: Armandine Les Landes et al. (2014)
35. Silins and Rothwell (1998), in: Armandine Les Landes et al. (2014)