Jean-Noël Marien: "From natural to planted forests: a continuum of situations"

How do we define a planted forest?

Jean-Noël Marien: Planted forests can be defined simply as wooded formations created, in one way or another, by man. Planted forests are thus very different from natural forests, whose succession and evolution are governed by natural processes alone, without human intervention. Planted forest ecosystems generally have a more simple form of biodiversity than natural forests. Plantations may have very varying vocations, and the most productive are often more fragile than natural forests. However, it is vital not to oppose natural forests and plantations in the broadest sense of the term. In reality, there is a continuum of complementary situations and techniques. In some cases, forests are planted on the fringes of protected areas. Such plantations form a protective cordon for natural species and provide a certain number of products that mean local people to not have to use natural forests. This is the case in the Democratic Republic of Congo and in Brazil, where a law obliges farmers who clear forest to keep 70 to 80% of their land wooded, including both natural and planted forest. Elsewhere, degraded natural forests may be enriched to give them added value in terms of biodiversity or economic aspects. This results in restored or transitional forests within which local species are used and which conserve all the functions of natural forests. These examples, like those of clonal industrial plantations, village or agroindustrial agroforests, assisted natural regeneration or periurban forestry, are only different versions of the same concept.

What role do planted forests now play in the forest area as a whole?

J.-N. M.: Logging, even sustainable, in natural forests alone can no longer satisfy the increasing demands from society. It is facing increasingly strong constraints: environmental, social or population pressure, and growing demand for goods and services. Planted forests thus help to satisfy increased demand and are playing a growing role. They are practised on very varying scales, from self-sufficient local players up to industrial plantations covering hundreds of thousands of hectares. Planted forests are traditionally used to produce wood and generate woody resources for specific purposes (fuelwood, paper pulp, sawn timber, etc). They are now an integral part of management plans, in which they provide added economic or ecological value. They indeed produce wood, but also help respond to demand in terms of biodiversity or carbon. They provide an answer, among others, to the challenges surrounding global change (climate, energy, water, agriculture, etc). Planted trees also play a vital social role. They are a very visible marker of land tenure and generate income in rural areas, which are often deprived. Planted forests thus help to generate environmental value, for instance by protecting sensitive areas (erosion, protected areas, etc). They serve to structure and organize territories. The ratio between urban, rural and forest areas is currently changing in the South: trees are becoming part of the urban and periurban structure, just as they have in the North.
However, things are not uniformly rosy, and planted forests, like any crop, often come in for criticism for their actual or assumed impacts on the environment. In particular, this is the case with highly productive plantations of exotic species. Nevertheless, there are ways of minimizing the adverse effects and optimizing the expected benefits of the investment put in: improving varieties and planting and cropping techniques and, for instance, monitoring sustainable management criteria and indicators, as with natural forests.

What do you think the future holds for planted forests in the tropics?

J.-N. M.: Planted forests are spreading rapidly. They now account for 5% of the total forest area, and look set to continue to spread. As a result, this extension could lead to tension, for instance concerning land tenure in some available areas, such as grasslands, extensively cropped areas or degraded anima; production zones. Such areas may be coveted for other speculative activities, particularly agroindustrial. In terms of short-term financial returns, it is almost undisputable that soybean, animal production and oil palm are more profitable than wood production. Researchers are now working on new varieties tailored to this constraint, against a backdrop of climate change. However, planted forests really come into their own when it comes to making use of impoverished land, be it grassland or cleared or degraded land, which is too poor to support intensive animal or crop production. We can therefore assume that in the next ten years or so, planted forest will play an ever-growing role, and that we shall see a diversification of their uses and products in the broadest sense and possible competition with other activities and types of land use.

Interview by Elsa Bru