Why forests and trees are important in drylands
Trees and forests are essential to the lives of people and animals in drylands. They can supply many of the basic needs of human communities, such as food, medicine, wood, energy, and fodder for livestock. In drylands more than in most other biomes, however, the demands of human communities have been much higher than the capacity of ecosystems to deliver sustainably, resulting, in many places, in the rapid depletion of these resources, leading to land degradation and desertification.
Many dryland tree species are emblematic because of their key ecological and cultural functions and the important environmental services they provide:
Provisioning services
Forests and trees in drylands provide products for day-to-day livelihoods and to generate income, including a large variety of non-wood forest products such as fodder, fruits, seeds, flowers, cork, gums, resins, honey, tannins, colorants, aromatics and medicines. They offer a safety net against poverty to millions of people living in the drylands.
Regulating services
Trees and forests in drylands facilitate the infiltration of water into the soil, redistribute water upwards – thereby improving nutrient cycling and the water balance – and help maintaining air humidity, reduce soil erosion by wind and water and moderate local climates by acting as windbreaks and providing shade for soils, animals and people. They constitute a buffer against drought and desertification.
Habitat and supporting services
Dryland forests and landscapes play a crucial role in providing habitats for fauna and flora. Although the absolute number of species in drylands is lower than in more humid environments, the rate of endemism is high. Drylands are also characterized by species that are highly specialized and adapted to the extreme dryland conditions including drought, salinity, temperature extreme variations and heat. Many dryland species, therefore, potentially have great value in efforts to adapt to climate change. Furthermore, the biodiversity of drylands forms the basis of diverse livelihoods, and its conservation and sustainable use is a key to improving livelihoods.
Cultural services
Dryland trees, forests and other wooded lands contribute to cultural identity and diversity, cultural landscapes and heritage values, and spiritual services (Le Floc’h and Aronson, 2013). In many countries, sacred forests and sacred or totem plant species have served to protect emblemic trees.