The forest is what is known as an ecosystem: it is an environment containing a range of living organisms that interact with each other, and in which trees play a central role in the overall functioning, both in terms of relationships within and between species and in the cycles of resources such as water and matter. Forest biodiversity is defined as all the diversity of living species found in the forest or interacting with the forest ecosystem. This term also includes the interactions of species with each other and with their environment. Forests are rich and complex ecosystems that are home to significant biodiversity. Each species plays a unique role and contributes to maintaining the ecological balance.
I. The importance and role of forest biodiversity
Forests are the terrestrial environment that shelters and nourishes the most living beings (80% of the world’s terrestrial biodiversity is found in forests). For example, forests provide a habitat for 80% of amphibian species, 75% of bird species and 68% of mammal species. Approximately 60% of all vascular plants are found in tropical forests. It is generally accepted that a significant proportion of a forest’s biodiversity is concentrated in the soil and dead wood. In France, for example, 25% of forest biodiversity depends on dead wood for food, protection and reproduction. French forests cover almost 16.4 million hectares, including more than 9 million hectares of overseas forests (mainly tropical), which are among the most diverse and rich in biodiversity.
Forests and their associated biodiversity provide many ecological goods and services that are fundamental to our survival and well-being. In particular, they play an essential role in regulating the climate. Through photosynthesis, trees absorb carbon dioxide and release oxygen, helping to reduce greenhouse gases. Forests also influence the water cycle by absorbing rainfall and slowly releasing it into rivers and groundwater, thus preventing soil erosion. Forests regulate air humidity through transpiration, a process by which leaves release water vapour into the atmosphere. This contributes to cloud formation and, consequently, to rainfall. Forest biodiversity is also an invaluable source of natural resources. Forests provide numerous products, including wood, of course, but also fibre, food, medicinal plants and game. They also contribute to agricultural production by providing shelter and nectar resources for pollinators. These products can be essential for certain communities that depend directly on forests for their livelihoods.
II. Threats to biodiversity
Forest biodiversity faces numerous threats, which are generally divided into two main types: biotic and abiotic threats, and anthropogenic threats. However, humans are often partly responsible for all these situations.
Deforestation is one of the main threats facing the planet. It is generally the result of agricultural expansion, urbanisation and intensive logging. Every year, millions of hectares of forest are destroyed, resulting in the loss of numerous habitats and resources for many animal and plant species. Unregulated or unsustainable logging is another major concern, as intensive timber extraction without proper planning is leading to a rapid depletion of forest resources. In addition, human infrastructures (e.g. roads, dams and urban areas) fragment forest habitats and isolate animal populations from each other (whereas exchanges between them are necessary for their survival). Humans are also often responsible, intentionally or more often unintentionally, for introducing invasive species and diseases into forest ecosystems. These species can compete with native species for resources, disrupt food webs (which link primary producers such as trees, consumers such as deer and decomposers such as fungi or soil bacteria) and even lead to the local extinction of endemic species.
In addition to deforestation, forests are threatened by fire, often exacerbated by climate change. Climatic variations, such as rising temperatures, prolonged droughts and extreme weather events (e.g. storms), affect the health of trees and change the composition of forests. Insect pests and diseases, whose abundance is also influenced by climate change, can attack weakened trees and accelerate their decline.
III. Protecting forests
To protect biodiversity and essential forest resources, as well as to prevent natural hazards, it is crucial to implement conservation measures. In particular, forests can play an important role in mitigating the effects of climate change. This includes creating and managing protected areas, promoting sustainable forestry practices and educating the public about the importance of preserving their environment. For example, public and private forests in France are managed according to plans that aim to balance timber production with the protection of animals and plants. Protected areas, meanwhile, play a key role in preserving wildlife, ecosystems and landscapes, while providing essential services such as combating climate change.
Forest conservation in France means managing forests in such a way as to maintain their ecological, economic and social functions over the long term. This includes sustainable forest management practices such as selective logging, reforestation and maintaining species diversity. Management policies also include forest fire prevention, pest and disease control, and the promotion of environmentally friendly forestry practices. In France, forest management serves several objectives at once and must be sustainable. The National Forest and Wood Programme (PNFB) for the period 2016-2026 defines the rules to be followed for the next 10 years. Two main labels certify that forest management complies with the principles of sustainable forest management: the PEFC (Programme for the Endorsement of Forest Certification schemes) label and the FSC® (Forest Stewardship Council®) label. Reforestation and restoration programmes for damaged forests are also essential to restore the ecological balance. Restoration can aim to diversify species, reintroduce native species and re-establish natural habitats for local wildlife.