Planting trees is often the quickest and most effective way of producing new biomass, thus helping to offset the loss of carbon resulting from deforestation or forest degradation. Investing in new carbon stocks has great potential to make a significant, fast and measurable impact on climate change without requiring sweeping changes in policies, cultures or national economies. Several developing countries, notably in Asia, have demonstrated that major investments in planted forests can reverse the trend towards deforestation and result in a net increase in forest area.

The UNEP report Towards a green economy: pathways to sustainable development and poverty eradication (the Green Economy Report; UNEP, 2011) calls for investments in reforestation of USD 22 billion per annum over the next 40 years. This level of reforestation would certainly increase the sequestration of carbon in woody biomass, and may be large enough to have an impact on climate change. Planted forests must be designed for local conditions; the trees must be appropriate, ideally native species; and planting programmes must take local cultures and economic conditions into account.

Protecting and enhancing ecosystem services from existing forests can be a powerful complement to establishing new forests and planting trees outside forests. Forest landholders can be rewarded for maintaining healthy forests and encouraged to restore other forests through payments for forest-based ecosystem services, such as carbon sequestration, providing clean water or conserving biodiversity. Several countries have implemented small-scale programmes that demonstrate the effectiveness of such efforts. In one example, forest owners receive payments for managing forested watersheds in ways that reduce the cost of generating electricity from hydropower. Payments for the ecosystem services of forests can be used to create new forests and enhance the quality of existing forests. REDD is one of the most widely discussed and promising examples of such payments.

Trees sequester carbon, regardless of their location, so they may be planted on farmland and rangeland and in cities: outside the “forest” as officially defined by FAO. Agroforestry – incorporating trees into farms – is an essential component of global efforts both to enhance rural livelihoods and to mitigate climate change. A total of more than 1 billion hectares of agricultural land – half of the world’s farmland – currently has tree cover of more than 10 percent. Farm forestry contributes up to 40 percent of farm income through the harvesting of wood, fruits, oils and medicines from trees.

Trees can also provide fodder for livestock, help enhance soil fertility, and provide environmental benefits such as clean water, soil health, carbon sequestration and biodiversity. Trees add both market and non-market value to rangelands.

In cities, trees provide ecosystem services: shade from heat, shelter from wind, absorption of pollution, and creation of urban biodiversity. Urban trees also have aesthetic benefits and add value to property.

The energy sector is responsible for more than half of anthropogenic GHG emissions; however, when managed properly, the production of electricity by burning wood instead of coal can reduce GHG emissions by up to 98 percent when the entire life cycle is taken into consideration. Increasing the use of renewable energy, including wood-based fuels, relative to fossil fuels may therefore be one of the most important components of a global transition to a sustainable economy.

Combustible renewables and waste currently account for about 10 percent of the world’s energy production. This includes the wood energy used by households in developing countries that include promoting the use of efficient and clean burning devices and providing training in efficient, sustainable and legal charcoal production, to improve energy efficiency and reduce pressure on natural resources.

Increased use of wood for energy will also present challenges to existing users of forests and forest resources. Policies for increasing the demand for woodfuels must therefore be accompanied by good forest policies and effective institutions to implement them.

Governments can also pursue climate- and forest-friendly policies by encouraging greater recycling of wood-based products. Wood products, notably paper and paperboard, have been recycled for decades; every year more than 200 million tonnes of paper is recovered and recycled, accounting for roughly half of total consumption.

Ensuring effective collaboration among donors and government agencies in developing countries is a prerequisite for improving the governance, monitoring, assessment and management of forests. To maximize forests’ contributions to a sustainable future, policies, programmes and investments in forests must be taken into account in relation to other sectors. Notable areas for better communication and partnerships include the following:

Wood and wood products will make increasingly important contributions to a greener economy and more sustainable development. Realizing this potential requires overcoming several hurdles:

Although wooden buildings have traditionally been limited to only one or two storeys, innovative and engineered wood products are increasingly recognized as having potential for buildings of up to 20 or 30 storeys. It is very difficult to produce evidence of the direct environmental and GHG-mitigation benefits of using wood in building and construction. However, focusing on specific building products enables comparisons of the environmental impacts of wood and competing materials. This “material life cycle” approach measures the environmental impacts of building products at four stages: