Drivers of LEDD in forests & shrubland: general

Authors: Agostino Ferrara, Guiseppe Mancino, Luca Salvati

Editors note: Text source D311 section 3.2

In »LEDD issues in forests & shrubland worldwide we introduced and discussed the main LEDD issues which concern forests and shrubland worldwide, in the countries where the study sites are located and in the broader regions of the study sites themselves. These LEDD issues do not occur in isolation but are driven by interdependent environmental, economic and social processes, operating at multiple scales, singly and in combination with each other.

This section of the Deliverable report will discuss these key drivers at global, national and regional spatial levels.  Policy drivers are discussed here only briefly. For a full discussion of policy drivers in the three land themes, please refer to »Policy context and policy recommendations for LEDD in forests & shrubland: general.

The MEA (Millennium Ecosystem Assessment 2003, p.15) defines direct and indirect drivers of ecosystem change and their relationship as follows:

In LEDDRA, the above distinction is adopted. Practically, direct drivers of LEDD are intentional and unintentional human activities and interventions that cause changes to the characteristics of the environment; i.e. they cause LEDD directly (e.g. land management practices, deforestation, overgrazing, etc.). Indirect drivers are those socio-economic, cultural, institutional, political and other forces that drive people to undertake activities that may or may not cause LEDD (e.g. demand for food, prices, policies, norms, property rights, etc.).

Table 1 below presents the direct and indirect drivers of LEDD in forests & shrubland. Drivers operate at all spatial levels (global, national, regional, local); their specific operational form depending on the level concerned.

Table 1. Direct and indirect drivers of LEDD in forests & shrubland

Type of Driver
Examples
Direct drivers of LEDD 
Changes in local land use and cover Land abandonment; unsustainable land and forest management practices.
Species introduction or removal Introduction of new commercial crops; removal of vegetation cover during critical seasons of the year; changes in species composition as a result of grazing and forest fires.
Technology adaptation and use Mechanisation.
External inputs Fertilizer, pesticides, irrigation.
Harvest and resource consumption Forestry, timber extraction and energy demand.
Climate change Increased frequency of extreme weather events.
Other natural, physical and biological drivers
Loss of local knowledge of traditional techniques.
Indirect drivers of LEDD
Demographics Changes in population structure and spatial distribution such as  rural out-migration of young people; ageing populations in coastal areas etc.
Economic Changes in national and per capita income; international trade flows; changes in global, regional and local market prices; macroeconomic policy.
Socio-political Democratization; changes in the role of women; changes in civil society.
Science and technology Adoption of new technologies including biotechnology and information and communication technologies; changes in research funding.
Cultural and religious Social norms surrounding consumption; materialism; changing religious practices etc.

Source: (Adapted from Millennium Ecosystem Assessment 2003)

The drivers of land and ecosystem degradation and desertification (LEDD) are generally human-induced and they are related to the social, economic and political conditions prevailing in places where forests & shrublands provide important resources and services to nature and society (Hassan et al., 2005). However, in the last decades, environmental factors and global scale natural disturbances play a key role in forest ecosystem dynamics, also acting as key drivers of ecosystem degradation and desertification.

Agriculture

Historically, agricultural activities have been the most important direct drivers of land use change, mainly involving the clearing of forests & shrublands to convert them to cropland and pastures. In the last decades, the increasing demand for new land to produce food, feed and fuel has been met through deforestation. As estimated by Gibbs et al. (2010), during the 1980s and 1990s, more than 80 percent of new agricultural land in the tropics came from intact and natural forests representing easily accessible areas with fertile soil, allowing rainfed agriculture, and at the same time with saleable tree species. An example is the conversion of Asia's rainforests for oil-palm cultivation.

The contribution of individual agricultural activities to forest fragmentation, forest productivity decline and desertification processes is influenced by the prevailing economic, demographic and technological conditions at the regional level. For example, a smallholder with a low level of productivity per hectare, with poor technological infrastructure, needs more land than a larger and technologically advanced farm. Also, extensive cattle production requires more land than intensive vegetable cultivation. Likewise, higher timber prices put pressure on old growth forests but, at the same time, they create incentives for reforestation. Deforestation dynamics driven by agriculture and pasture depend on the type of agricultural system, the level of development, distance from markets and commodity prices. In Africa, deforestation is caused mainly by small-scale farming and fuel wood collection, while in Latin America it is driven more by large-scale agriculture, and in particular by extensive cattle production. In the Asia-Pacific region, the agricultural sector is still the most important deforestation driver. A clear example of this type of process is represented by large-scale agriculture in the Brazilian Amazon, which contributes to deforestation through the conversion of forests to cropland, but which has started with small-scale timber extraction and subsistence agriculture. Recently, the expansion of large-scale mechanised agriculture at the forest frontier has been driven by an increase in soybean cultivation. As shown by Morton et al. (2006), in the Brazilian state of Mato Grosso, there is a significant correlation between deforestation and the price of soybeans (Figure 1).  

  Figure 1. Trends in land use after 2001-2004 deforestation events >25 ha in Mato Grosso state, Brazil. Summary of conversion dynamics by post-clearing land cover from satellite-based phenology information in the years after forest clearing. Inflation-adjusted prices per 60-kg sack of soybeans for the same period as the annual deforestation increment (September-August) are plotted on the right-hand axis in Brazilian Reais (R$). Source: (Morton et al. 2006)

Agricultural activities characterised by poor practices and unsustainable management are also important drivers of soil erosion and compaction processes, forest fires, forest productivity decline and loss of biodiversity. One of the most important characteristics of these agricultural drivers is poor land management techniques such as overgrazing. Overgrazing is generally linked to land ownership issues, as traditional land tenure rights and communal land use patterns sometimes result in overgrazing of communal areas. Overgrazing can be considered as a key driver of land degradation, erosion and desertification through a decline of forest productivity. In particular, overgrazing from cattle, sheep and goats in forests & shrublands can lead to soil erosion and to bush encroachment and also limits natural forest renovation, leads to loss of biodiversity and forest productivity decline; a very different practice from a moderate use of grazing that may instead be useful in some phases of forest management.

Forestry, timber extraction and energy demand

Forests worldwide represent a very valuable natural resource, providing a wide range of wood and non-wood forest products. In particular, wood is one of the world’s most ubiquitous and important industrial raw material and source of energy.

The international demand and trade in forest products (wood and wood products) has increased with an average annual growth rate of 6.6 percent over the last 30 years (Advisory Committee on paper and wood products 2007). This fast growth was mostly the result of developments in the international trade in secondary processed wood products (an average increase of above 8 percent per year); particularly wooden furniture. However, these data are underestimated due to the lack of information on domestic consumption of fuel wood.

Forest management and silvicultural practices play a significant role in land use change and, if improperly applied, in forest ecosystem degradation worldwide. Differences across continents, regions and countries in environmental, socio economic and technological conditions determine different forest resource exploitation and management models, leading to different pressure levels and problems in forest ecosystems. In particular, mismanagement and overexploitation of forests is the main cause of forest ecosystem degradation. Furthermore, in many developing countries, poverty and the lack of policies and laws regulating forest resource exploitation are other indirect drivers, which lead to unsustainable wood extraction.

As a result, some common forest management systems for timber production can often lead to the transformation of a healthy forest into a simplified structure or even a monoculture for timber. Silvicultural practices have usually favoured one or a few species, depending on particular characteristics such as productivity, growth rate, quality and quantity of wood production and sprouting capacity, among others. This simplification of forest systems has impacted different structures and processes at different scales, from the stand to the landscape level, with loss of biodiversity and general forest degradation due to the change from complex forest ecosystems into simplified, even-aged monoculture stands.

In other cases, according to Laporte et al. (2007), forest mismanagement leads to overexploitation of forest resources. Industrial logging has become the most extensive land use in central Africa, with more than 600,000 square kilometres (30 percent) of forest currently under concession. It is expected that industrial logging concessions will expand further, with commensurate increases in the rates of deforestation and degradation. Related to logging activities, the practice of selective logging represents the felling of one or two trees, leaving the forest around those trees intact. Selective logging, often believed to be a sustainable alternative to clear-cutting, is also responsible for forest degradation with loss in biodiversity and forest productivity decline. As large trees are logged, the canopy thins, drying the forest and increasing its vulnerability to agricultural fires set in surrounding areas.

The main current and past use of wood worldwide is as a fuel, representing the world’s most important form of non-fossil energy. Today, millions of people in developing countries are reliant upon wood for energy production. Africa and Latin America are the main regions where wood is used primarily for heating and cooking. The largest producers of fuelwood are India, China and Brazil. The United States, Mexico, Finland, Sweden and Austria are also large producers and consumers of fuelwood, amongst the industrialised countries (Steierer et al. 2007). In recent years, wood has attracted attention as a renewable energy source and, thus, an environmental friendly alternative to fossil energy (FAO 2008). In Europe and North America, fuelwood consumption has been influenced by new processing technologies with the production of pellets, briquettes and cellulose-based ethanol.

The responses to this increasing demand for fuelwood vary worldwide, with different pressures and problems on forest ecosystems. In developing countries the main problem is deforestation due to severe overexploitation and depletion of forests, especially in the case of open-access resources with poorly defined property rights.

In other cases, increasing demand for fuelwood has transformed entire forest sectors, with changes in forest management and forest composition. In particular, forest owners and managers have started planting and managing monoculture fast-growing plantations for wood energy. Forest plantations have a range of impacts in socio-economic and environmental terms in that they potentially offer many direct and indirect environmental benefits, but they may also have negative environmental and socio-economic impacts as well.

The introduction of fast-growing exotic species for industrial wood or biomass production represents an important opportunity for developing countries. Plantation management presents an opportunity to create economic flows, infrastructures and employment opportunities. The use of fuelwood to produce energy, rather than fossil fuels, could be considered a positive environmental benefit due to the considerable reduction in net carbon dioxide emissions (Nabuurs et al. 2007; Piao et al. 2009). Forest plantations offer other environmental benefits if they replace annual crops, heavily grazed pastures, or degraded lands. Benefits include protection against water pollution, soil erosion and wildfires. In contrast to these benefits, forest plantations can be considered drivers of biodiversity loss through alteration of forest structure, creation of monocultures and use of non-native tree species, which local wildlife are less able to use and, in some cases, these non-native species are invasive.

Extractive activities (mining)

On a global scale, mineral extraction activities are responsible for 15 percent of forest cover losses (Geist and Lambin 2002). This driver contributes to forest degradation or complete deforestation, depending on the size and type of the mining operation. Generally, mining areas are located in remote forested areas that are already exploited for wood products. In the Amazon basin, a variety of minerals such as diamonds, bauxite (aluminium ore), manganese, iron, tin, copper, lead and gold are extracted (Gurmendi 1999). The high economic value of these minerals encourages mining companies to extend mining operations and, consequently, to search for new sites, causing severe degradation and deforestation. As a result of the infrastructure needs associated with these extractive activities, large plots of forests are also cleared for the construction of new roads.  Finally, mining operations often have serious environmental impacts on water, soil and air quality, thus, indirectly affecting forest health.

Tourism

Increased tourism activity can have both positive and negative impacts on forest conservation, depending on how tourism is managed (Yuan et al. 2008). The creation of National Parks has undoubtedly helped to protect forest ecosystems but mismanagement of tourism activity has also caused damage in some areas. Generally, tourism is seen as offering economic opportunities and is, therefore, encouraged. However, tourism development may be implemented without associated monitoring and management strategies, which may be considered expensive or unnecessary, to the detriment of forest cover and quality.

Tourism pressures on forest ecosystems include urban expansion and infrastructure development, construction of tourist facilities and resorts, water, soil and air pollution, noise, light pollution, disturbance to wildlife, forest fires, soil erosion and compaction and loss of biodiversity. The impact on forests from tourism development is a concern for forest ecosystems worldwide (Nyaupane 2006; Bruyere 2009; Heinen 2010; Yuan et al. 2008).

Urbanisation

The term ‘urbanisation’ refers to an increase in the number of new settlements and also to the expansion of existing urban areas and it is one of the main direct drivers of land degradation processes (Munn et al. 2002; Zhang and Nagubadi 2005). Urbanisation encompasses a number of different processes such as urban sprawl, new settlements, coastal development and tourism development.  

Increasing urbanisation involves changes in land use not only in forest ecosystems and shrublands, but also in agriculture, as a result of land abandonment and agricultural land conversion. Impacts can also include a decline in the quality of forests in close proximity to urban areas. These phenomena have several consequences on socio-economic and ecological systems and result in changes in the availability of ecosystem resource and services. In particular, the increasing presence of centres of population increases or creates new demands for water, food, energy, transportation and infrastructure.

The impact of urbanisation not only involves land use change but also ecosystem change in terms of resource overexploitation and pollution, not only in the immediate vicinity of the urban area, but across the whole watershed. Pollutants may be transported through air or water to distant locations, for example as in the case of anthropogenic N inputs, which are responsible for coastal eutrophication (Faulkner 2004).

The key issues arise at the interface between the urban and forested area. Conceptually, the urban-rural interface is not simply a “peri-urban” zone or geographic interstice between the urban built environment and the rural landscape, but also it can also be considered as an array of networks connecting urban agents and rural producers (Browder 2002).

This interface involves not only biophysical processes such as land use changes, ecosystem fragmentation, limited water availability, habitat loss, biodiversity loss and nutrient cycling modification, but also socio-economic influences on rural and forested areas with increasing goods demands and market development, technological improvement and more new land use in general.

In Europe, and especially in the Mediterranean basin, urban regions have experienced population and economic growth (Longhi and Musolesi 2007; Turok and Mykhnenko 2007), leading to a marked transition from compact urban forms to more dispersed or polycentric developments (Weber et al. 2005; Kasanko et al. 2006; Couch et al. 2007). The process of spatial diffusion of both the urban population and economic activities over a wider area has modified the growth-oriented model traditionally observed in several Mediterranean urban areas by introducing new forms of relationship between coastal and inland spaces, urban and rural territories, central and peripheral zones. The process of city spread, the growth of centres out of the traditional boundaries of the compact city, as well as the consolidating sprawl and distribution over seaside areas are the direct drivers of land use conversion and soil sealing (Genske 2003). Their importance has been enhanced by the intrinsic ecological fragility of the Mediterranean landscape, which is also subject to climate change and increasing aridity and drought (Johnson and Lewis 2007). Urban spillover across neighbouring agricultural land, the consequent disappearance of the urban-rural gradient typical of southern Europe, progressive habitat fragmentation and the formation of a mixed landscape are all drivers of soil degradation in peri-urban areas.

Forest fires

Forest fires represent another important direct driver affecting forest and shrubland ecosystems with dramatic environmental, social and economic consequences. Forest fires have large negative impacts on both regional and continental scales, affecting biodiversity, ecosystem balance and productivity and the livelihood and health of local people. Also, they negatively affect infrastructure, transport and the forest industry. Globally, forest fires are also responsible for the release of large amounts of greenhouse gases to the atmosphere. Not only can fires cause changes in CO2 levels, which can lead to shifts in the carbon (C) balance and enhanced emissions of greenhouse gases, but increases in atmospheric CO2 levels and global warming can feedback on fire regimes and fire severity. On a regional scale, fires account for nearly one third of anthropogenic CO2 equivalent emissions (Schimel and Baker 2002).

At the local scale, forest fires strongly impact forest landscapes, altering their ecosystem balance. An important factor in the level of damage caused by fires is the combination of their effects and frequency, which can lead to different stages of structural regression, particularly in Mediterranean forests. The principal problem is a decline in forest ecosystem succession and a transition from forest to savannas, shrubland and grassland (Figure 2). These processes lead to the destruction of habitats, reduction or elimination of plant and animal species with consequent negative effects on biodiversity (Alvarez et al. 2009; Acacio et al. 2009).

  Figure 2. Rate of transitions (percent of transitions per year) from each vegetation patch-type to the others (1958–2002). Source: (Acacio et al. 2009)

Usually, there is a reduction in the amount of biomass, with negative effects on soil protection, leading to soil degradation (erosion, alteration of chemical and physical soils characteristics, landslides etc.). In particular, alterations of soil chemical and physical characteristics involve changes in soil porosity, with a general reduction in soil ventilation and infiltration capacity, reduction in organic matter content and the development of a hydrophobic layer at a depth of 10-15 cm (Bárcenas-Moreno et al. 2011; Martí-Roura et al. 2011).

Severe fires, such as wildfires, generally have several negative effects on soil. They cause significant removal of organic matter, deterioration of both structure and porosity, considerable loss of nutrients through volatilisation, ash entrapment in smoke columns, leaching and erosion, and marked alteration of both quantity and specific composition of microbial and soil-dwelling invertebrate communities. However, despite common perceptions, if plants succeed in promptly recolonising the burnt area, the pre-fire level of most properties can be recovered and even enhanced (Certini 2005).

Human activities cause most fires in forests & shrublands. In general, they are the result of misuse of fire for conversion of forests to agricultural lands, maintenance of grazing lands, extraction of non-wood forest products, hunting, and clearing of land for mining, industrial development and resettlement. Forest fires may also be the result of personal or ownership conflicts. In Mediterranean forest ecosystems, fire disturbance is a primary agent of change, shaping the distribution and composition of most plant communities in these regions. Rare causes for forest fires are the result of leisure use of forests such as unattended camp fires or barbeques and discarded cigarette butts.

Fire impacts on land cover condition and community dynamics may be extreme and/or irreversible if the disturbance regime exceeds its natural range of variability and return time (Dale et al., 2000). The natural fire regimes in the world’s Mediterranean forests have been altered through intensive and extensive land use change as well as intentional use and suppression of fire (Espelta et al. 2002; Pausas 2003). The magnitude and direction of these changes vary from region to region. However, the impact of altered fire regimes may be more influential than climate factors in shaping future Mediterranean forest ecosystem dynamics (Syphard et al. 2007).

Deforestation

Deforestation processes represent a direct driver of forest ecosystem degradation worldwide. Deforestation is generally related to land clearance for agriculture, mineral extraction, construction of reservoirs for hydro-electric power generation, transport infrastructure, forestry, wood extraction, urban settlements and tourism development. Land cleared for agriculture may eventually lose its fertility and become suitable only as rangeland. Deforestation continues at an alarmingly high rate of approximately 13 Mha per year (FAO 2010a). At the same time, reforestation, landscape restoration and natural expansion of forests have significantly reduced the net total loss of forest area. Net global change in forest area in the period 2000–2010 is estimated at -5.2 Mha per year, down from -8.3 Mha per year in the period 1990-200, with few signs of a significant decrease over time due to reforestation/afforestation and natural expansion of forests in some countries and regions. South America has suffered the largest net loss of forests, followed by Africa (Figure 3) (FAO 2010).

Deforestation processes are often linked to socio-economic and political pressures, flowing from the needs of growing populations living in marginal areas at subsistence levels. Much more important is deforestation caused by land use change: from natural rainforest to monoculture plantations of highly profitable crops such as palm oil (Elaeis guineensis) in the Far East. Furthermore, the combination of these processes with poor harvesting and agricultural practices represent the main causes of soil erosion and land desertification.

  Figure 3. Annual change in forest area by region 1990–2010. Source: (FAO, 2010)

Climate change

In the last few decades, changing climate conditions have been one of the most important direct biophysical drivers affecting forest ecosystems and shrublands. The increasing number of extreme climatic events is considered a significant cause of forest degradation and tree mortality (Allen et al. 2010). Attribution of the specific cause of forest degradation, however, is often difficult due to the multiplicity of potential drivers noted in the preceding sections. Evidence reported by Williams et al. (2010) showed that increasing drought and heat waves were positively correlated with the incidence of wildfire, insect pests and increased disease risks in high density forest stands, suggesting the key role of forest management in the mitigation of forest degradation risk.

forests & shrublands are more sensitive to climate change effects under semi-arid or dry sub-humid climatic conditions and irregular rainfall with long dry periods and high summer temperatures. The forest degradation process is characterised by forest productivity decline, soil degradation with loss of organic matter content and loss of biodiversity. Besides these responses to climate change, on a global scale forest ecosystems are able to influence climate through physical, chemical, and biological processes that affect global energy exchanges, the hydrological cycle, and atmospheric composition. These complex and nonlinear forest-atmosphere interactions can dampen or amplify anthropogenic climate change. Tropical, temperate, and boreal reforestation and afforestation attenuate global warming through carbon sequestration. Tropical forests mitigate warming through evaporative cooling, but the low albedo of boreal forests represents a positive forcing of climate change, with warming effects on atmosphere (Bonan 2008).

Policies

Policies represent an important indirect key driver involved in the mitigation and prevention of land degradation, but at the same time they may have detrimental effects on forest ecosystems. Policies concerning land, water and natural resource management affect forest ecosystems and shrublands by regulating activities and protecting the environment against LEDD. However, other policies, such as economic, development and infrastructure policies may also have indirect impacts on the way that forests are managed and used. In this way, policies represent one of the most important challenges for local, regional and national governments to design sustainable management of renewable natural resources (FAO 2010b). Forest policies represent an important indirect driver to preserve the regulating, supporting, provisioning and cultural forest ecosystem services. A more complete discussion on forest policies is described in »Policy context and policy recommendations for LEDD in forests & shrubland: general.

In many developing countries the lack of policies dedicated to forest ecosystems, the large amount of unallocated public lands and poor institutional and regulatory capacities have often been responsible for deforestation and land degradation processes. According to the World Bank, estimates of illegal logging around the world account for US$15 billion per year (Contreras et al. 2007). In the last few decades, the growing interest of the international community in the role of forests in the mitigation and regulation of global biochemical and climate processes has provided a strong stimulus for the development of more effective policies and for better and more efficient land, water and natural resources management (FAO and ITTO 2009).

Starting with the United Nations Conference on Environment and Development (UNCED) in 1992, the declaration of “Forest Principles” and Chapter 11 of Agenda 21 “Combating Deforestation”, forest policies have been further developed within the Intergovernmental Panel on Forests (IPF) in 1995. The main objectives of IPF were to formulate options for further actions in order to combat deforestation and forest degradation, to promote international co-operation in financial assistance and technology transfer, scientific research, forest assessment, and development of criteria and indicators for sustainable forest management. In the period 1997-2000, the Intergovernmental Forum on Forests (IFF) was established to address the main issues and criticism pointed out by the IPF. In October 2000, the Economic and Social Council of the United Nations (ECOSOC), in Resolution 2000/35 established the United Nations Forum on Forests (UNFF). The UNFF1 Report outlined the UNFF Plan of Action and the first Multi-Year Programme of Work (MYPOW) from 2001-2005.

The key role of forests in climate change mitigation has been established within the Intergovernmental Panel on Climate Change (IPCC), and with the Kyoto Protocol  “Annex-1” countries (i.e., industrialised) may use CO2 removals (i.e., “sink”) from LULUCF to meet their emission reduction targets during the first commitment period (2008-2012). In particular, a country must include emissions and removal from direct human-induced Afforestation/Reforestation/Deforestation since 1990, and may include any of the following “activities”: forest management, cropland management, grazing-land management, re-vegetation (Grassi et al. 2010). In this way, the “Annex-1” countries of the Kyoto Protocol have developed most of their forest policies with relevant effects on land use and forest management in the last decade.

Finally, with the Copenhagen climate conference, the negotiation for emission reduction and mitigation between countries will be based on the mechanism of UN-REDD (United Nations Collaborative Programme on Reducing Emissions from Deforestation and Forest Degradation in Developing Countries). This programme, to be implemented on a voluntary basis in the developing countries, is widely considered a cost-effective strategy to reduce emissions from deforestation and an essential tool to encourage developing countries to act against climate change through the implementation of effective forest policies.

As already mentioned policies or their misapplication may have detrimental effects on forest ecosystems and thus may be considered both as indirect and direct drivers of LEDD issues in forest and shrubland ecosystem. An example is the set-aside policy of the European Union which, starting from 1988, has been modified several times in order to mitigate the unexpected negative effects of the set-aside policy itself from both environmental and socio-economic points of view. To this end, the European Union introduced Directive 42/2001/CE concerning the introduction of a new strategic environmental assessment tool (SEA), in order to evaluate a wide range of public plans and programmes (e.g. on land use, transport, energy, waste, agriculture, etc) and avoid unexpected detrimental effects of EU policies.