Dryland Forestry

An estimated 10–20% of the world’s drylands suffer from one or more forms of land degradation (MEA, 2005).

Challenges today and ahead

Drylands face numerous challenges linked to desertification, population pressure, climate change, and overharvesting and mismanagement. Changing land uses and practices such as the transformation of rangelands and other agrosilvopastoral systems to cultivated croplands, wasteful and unsustainable water use, inappropriate cultivation and grazing practices, and the overharvesting of woodfuel are leading to land degradation and desertification, water shortages and major losses of environmental services.

Many people living in drylands are locked in a vicious circle of poverty, irrational practices and environmental degradation. Moreover, climate change is expected to increase the incidence of extreme weather events such as droughts and to exacerbate desertification and declines in land productivity.

Water scarcity

Water scarcity

The lack of water exacerbates the effects of desertification through direct, long-term impacts on land and soil quality, soil structure, organic matter and soil moisture. 

In turn, the physical effects of land degradation have negative impacts on the availability, quality and quantity of water resources by inducing the drying up of freshwater bodies; increasing the frequency of drought and of sandstorms and dust storms; intensifying floods; and inducing declines in soil nutrients and vegetation cover. Further land and water degradation can also trigger indirect effects, such as surface and groundwater pollution, siltation and the salinization and alkalization of soils.

The challenges and threats posed by water scarcity in drylands are expected to increase in the future. 

Climate change and variability

Climate change and variability

The main challenge posed by climate change in drylands is likely to be an increase in the frequency, magnitude and severity of such events, including prolonged droughts, intense heat waves, heavy precipitation and strong winds. Some consequences of this increase are already apparent: uncontrolled largescale forest fires; massive forest dieback and pest attacks; major reductions in soil water storage capacity; and large-scale floods that accelerate and intensify soil degradation processes.

Climate change can magnify the effects of socioeconomic change, and vice-versa, potentially triggering faster rates of degradation and landscape-scale impoverishment.

Desertification

Desertification

The Millennium Ecosystem Assessment (MEA, 2005) described drylands as “highly prone to desertification on account of their limited primary productivity and generally slow recovery following human disturbance” compared with other biomes. 

According to UNCCD (1994), desertification is land degradation in arid, semiarid and dry sub-humid areas resulting from various factors, including climatic variations and human activities. The degradation of land resources in arid, semi-arid and dry sub-humid areas results from a process or a combination of processes primarily caused by:

  • vegetation degradation and fragmentation,
  • soil degradation due to erosion, compaction, nutrient mining, the loss of soil biodiversity, salinization (especially associated with irrigated lands), sand encroachment and contamination.

Biodiversity loss

Biodiversity loss

Water limitations and climatic extremes in drylands render endemic species vulnerable to disturbance and mean that recovery is slow. 

Poverty and food insecurity

Poverty and food insecurity

In general, socioeconomic conditions in drylands lag significantly behind those of other regions, and most of the world’s poverty is concentrated in drylands, especially in Africa and parts of Asia and the Near East (UNDP–UNCCD, 2011). 

Drylands are home to 2 billion people – about 30% of the global population – in over 100 countries.

The majority of people directly affected by desertification live below the poverty line and lack adequate access to freshwater (UNCCD, 2011).

Poverty and food insecurity, often coupled with unclear tenure rights over natural resources, drive people to overexploit remaining natural resources, which accelerates land degradation, leading to even greater poverty and malnutrition. 

Disrupted transhumance, migration and conflict

Disrupted transhumance, migration and conflict

Environmental degradation, especially desertification, is a frequent cause of migration, forcing people to move away from unproductive lands. 

Pastoral transhumance – the seasonal movement of people with their livestock to available pastures and watering points – is a traditional practice in drylands worldwide that enables the rational use of rangeland grazing resources (IUCN, n.d.); it is also a coping strategy that could be important for adapting to climate change. Population pressure, the weakening of traditional controls over the use of range resources, increasing land-use conflicts, the general trend towards sedentism among former transhumant communities, and environmental stresses are affecting the sustainability of land use and in some cases causing conflicts. The migration of dryland-dwellers in response to societal and climatic changes is another critical issue.

It has been estimated that up to 50 million people could be compelled to migrate in the ten years to 2020 as a result of desertification if the problem is not addressed (UNCCD, 2011).

Weak governance and inadequate policies

Weak governance and inadequate policies

Weak governance is increasingly regarded as a root cause of the degradation and loss of natural ecosystems worldwide.

A lack of understanding about the important contributions of dryland forests and trees to national development and the fragile nature of dryland ecosystems has led to their undervaluation and a general lack of effective policies, investment, institutional support and planning processes to support dryland communities and the sustainable management of their resources. Development strategies have often been limited to policies promoting agricultural intensification, especially industrial crops that lead to the degradation of dryland natural resources such as wooded lands and rangelands. In many countries, the lack of coherent multi-sectoral approaches means that different ministries address different aspects in ignorance or isolation of each other, often with the result that government policies are contradictory. The absence of secure rights to natural resources (such as land access and management rights and the right to generate income or otherwise benefit from natural resources) is another major constraint on investment in sustainable management and restoration activities.