Forestry and Agriculture


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United Nations Environment Programme
Division of Technology, Industry and Economics

Freshwater Management Series No. 7

Phytotechnologies

A Technical Approach in Environmental Management

III. Examples of Environmental Applications of Phytotechnology >

I. Forestry and Agriculture

Forests are reservoirs of biodiversity. Preservation of their unique genetic characteristics is vital to the development of improved drugs, pesticides, foods and materials. To sustain renewable tree harvesting into the future, forest managers need to replace what they cut. Where forests have grown undisturbed for centuries, they are often impossible to replace. An important alternative therefore is to sustain the diversity of tree species through forest plantations. However, forest plantations can impact the environment through excessive use of chemical fertilizers, pesticides and herbicides. If in the long term they deplete the soil, these plantations become unsustainable. These potential impacts can be addressed in a number of ways, including:

	•	adding leguminous species to plantations to improve soil fertility and keep down weeds, reducing the need for both fertilizers and herbicides,
	•	leaving chipped logging residue and bark in the field to reduce nutrient loss and act as a mulch, which also decreases weed growth and the need for burning to prepare sites for subsequent plantings,
	•	using biological control against insect pests instead of using herbicides.

Climate also has a significant impact on the growth and viability of forests. A steady increase in average temperatures from global warming could dramatically alter today’s pattern of tree distribution, thereby putting certain species under stress and encouraging the spread of other species. In order to understand the adaptability of indigenous tree species to changes in climate, researchers in Finland are measuring the success of various tree species. They have established an arboretum and a gene pool forest with various species of conifers and hardwoods to maintain genetic diversity. The aim is to determine the factors that regulate tree characteristics, and to produce different varieties of seeds suitable for forest regeneration.

Agriculture is another important sector where phytotechnologies can be applied. The production and marketing of food and other farm products such as cotton and tobacco make up the world’s largest single industrial sector. An important focus of crop research is to develop plants that are resistant to insect pests and diseases.

One of the lessons learned from the widespread spraying of pests is that simplistic approaches to controlling pests or diseases do not last. Insect pests, with their rapid rates of reproduction, can quickly evolve resistance to toxic sprays, while the buildup of the same poisons causes populations of their natural predators to decline. The result is a rebound of organisms that are much harder to get rid of.

Integrated pest management is an agricultural practice that combines reduced use of chemicals with alternative management strategies such as crop rotation, inter -cropping (i.e., growing two or more compatible crops in the same field), organic fertilisation, and control by natural predators. Genetic information, combined with the knowledge of how ecosystems function, is essential for the development and implementation of these alternative agricultural practices. By understanding the relationship between environmental factors, biodiversity and genetic characteristics, scientists are better able to advance this more sustainable, ecologically based approach to agriculture.

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