Urban and Peri-urban Forestry

Urbanization and its economic, environmental and social consequences

“Especially in the developing world, where most emerging mega-cities are located, managing and catering for urban populations will be one of the main challenges of our time.”¹ With the majority of the world’s population now living in urban areas, finding solutions to these challenges is more urgent than ever, and UPF can be an important tool to address them.

Since last century the world has witnessed an exponential and continuous increase of its population. According to the United Nations, more than 7 billion of people populated the Earth in 2011 and this number is expected to increase to 9.3 billion by the mid-century. In fact, since 2008 and for the first time in history more than half of the world’s population lives in towns and cities, a percentage that is expected to swell to a 70 per cent by 2050, representing almost 6.3 billion people.

The number of cities with more than a million inhabitants reached 378 in 2000, while there were only 11 of them in 1900, and it is expected to reach nearly 600 by 2025. Although over the past decades the richest countries contributed significantly to this increase, nowadays most of the growth is occurring in less developed countries, particularly in the African and Asian regions where the unprecedented scale of urban growth is expected to double the 2000’s urban population by 2030.

For the most part, the rapid expansion of cities takes place without any real land use planning strategy and the incidental human pressure causes highly damaging effects on forests, landscapes, as well as other tree resources and green areas in and around cities. Natural and agricultural land areas are converted for urban uses, or for meeting the demand for fuel and building materials. The environmental impacts of urbanization, often intensified by climate change, in turn create greater issues for city dwellers: basic services, infrastructure, housing, livelihoods and health. For instance, residents of urban areas are more at risk of illnesses – such as respiratory infections and lead poisoning – caused by pollution from cars, fossil fuels burning and industries. In addition, it is estimated that 60 per cent of urban dwellers are living in areas of high risk of exposure to at least one natural hazard; flooding being the first and drought the second most frequent hazard.

Ultimately, degraded green resources and related urban environmental hazards can lead to:

• surrounding landscape fragmentation;
• resource access insecurity and decrease of food security;
• higher frequency and vulnerability to extreme weather events: floods, droughts, landslides and extreme winds;
• vulnerability of soil to erosion and watershed degradation;
• heat island effect;
• increase of the economic costs in terms of mitigation of climate change effects;
• increasing levels of pollution;
• increase of human diseases (such as cancer, cardiovascular diseases, allergies, obesity, etc.);
• loss in supply of non-timber forest products and rise of their prices;
• limited access to wood fuel products, both for industrial and domestic purposes.

These consequences are particularly evident in the developing countries, where poverty and hunger are moving from rural to urban and peri-urban areas, contributing to increase the economic and social degradation in and around cities. Also, precarious contexts in some developing countries often drive the UPF issues down in the priority list of urban decision-makers.

¹ Konijnendijk CC, Sadio S, Randrup TB, Schipperijn J (2004). Urban and peri-urban forestry in a development context - Strategy and implementation. Journal of Arboriculture 30: 269-275.