Timber Plantations

Benefits

While tree plantations constitute only 3.5% of the world's forested area, they are approaching 50% of global wood production. In addition to timber production, tree plantations are an important source of fuelwood in many parts of the world and can provide income from the sale of nontimber forest products (NTFPs) harvested from plantations. While NTFPs account for a much smaller portion of the revenue from plantations than timber, they can be locally important. For example, in the Ecuadorian Andes, an edible mushroom that grows in association with planted pines is harvested and provides an additional source of income. In recent decades, tree plantations have also been valued for their ability to sequester carbon in tree biomass, thereby playing a role in decreasing atmospheric carbon dioxide concentrations. In some cases, tree plantations can also sequester carbon in the soils where they grow. However, this depends largely on the land use prior to plantation: When plantations are established on croplands, soil carbon generally increases, while conversion of pastures or native forests to plantations generally causes a loss of soil carbon.

Costs

Although tree plantations can provide many benefits, there is increasing evidence that they can also cause the deterioration of ecosystem services, in particular water provision. Plantation establishment can decrease stream flow and groundwater recharge, cause acidification of stream [Page 2835]water and soils, and produce soil salinization. In many parts of the world, timber plantations have caused additional problems where the exotic species used have become invasive. The invasive spread of commercial plantation species has been recognized as a major threat to native biodiversity in South Africa, New Zealand, Australia, South America, and Hawaii.

A slash pine plantation in Georgia, United States. Although slash pine has the most limited range of the major Southern pines, more of it has been planted than any other Southern pine, or for that matter any timber species in North America.

Source: Jeff Vanuga, USDA Natural Resources Conservation Service.

Conclusion

The balance between the benefits and costs of tree plantations depends largely on the location in which they are planted. In particular, the type of soils, hydrology, and prior land use, as well as the condition of the landscape prior to plantation establishment, play an important role, as do the kinds of species used and the way in which the plantations are managed. The degree to which tree plantations can be considered a land use that contributes to environmental sustainability depends on how they influence the provision of ecosystem goods and services, including not only timber and fuelwood but also carbon, water, and biodiversity.

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