natural forest cover may continue declining in stage 4, but the loss being more than compensated for by the increase in plantations.

- (e) The notion of the FT is sometimes used interchangeably with the Environmental Kuznets Curve (EKC) for deforestation – the theory predicting a bell-shaped relationship between deforestation and income. Although some of the underlying ideas are related, they should not be equated. First, EKC uses income (GDP) per capita on the x-axis, while FT normally uses time. (These are of course related with positive economic growth, but the explanations used for FT tend to be broader.) Second, EKC implies accelerating deforestation at early stages, a stronger assumption than contained in FT, which simply suggests a period of deforestation. Third, EKC does not necessarily imply a period of reforestation as FT predicts.<sup>35</sup>

# **3.2 Driving forces in the FT**

In Figure 7 four distinct phases are distinguished (discussed in more details in section 3.3), as well as three key sets of drivers. Borrowing concepts from systems analysis, the movement along the forest transition curve can be seen as the result of three sets of forces.

The first stage, of relatively _undisturbed forest_ , is characterized by _passive protection:_ the forest area has poor infrastructure and market access, and is therefore inaccessible for commercial exploitation. A set of _triggers_ (force 1) starts the deforestation process, which accelerates through a set of _reinforcing loops_ (force 2) leading into the second stage, the _forest frontier_ . High levels of deforestation lead to forest scarcity, which – together with other socio-economic and political forces - initiate and/or strengthen a set of _stabilizing loops_ (force 3), leading into the third stage of _forest/agricultural mosaics_ . These stabilizing loops will eventually dominate, taking us into the fourth stage of reforestation termed the _forest/plantation/agricultural mosaics_ .

These forces can be clearly related to shifts in the land rent curves. Using a von Thünen model with only agriculture and forest, the stages can be described as done in Figure 8. The first stage (undisturbed forest) is characterized by low agricultural rents and therefore limited conversion from forest to agriculture. Then both the triggers and the reinforcing loops increase agricultural land rent, leading to a period of high deforestation during the second stage (forest frontier). A weakening of theses forces and a set of destabilizing loops will take us into the third stage, where deforestation slows down and eventually is reversed. This can take the form of reduced agricultural land rent, increased forest rent, or both. In the following we elaborate on these three sets of forces.

<!-- Start of picture text --> Agric. rent<br>Forest rent<br>Stage 1 Stage 2 Stage 3-4<br><!-- End of picture text -->

**Figure 8. Changes in agricultural and forest rent curves during the forest transition.**

## **_3.2.1 Triggers_**

The triggers refer to the initial shift in the agricultural land rent. The single most important physical, on-site trigger of deforestation is the construction of new and better _roads._ Previously inaccessible areas open-up for both in-migration of people (and capital), and also creates a market outlet for

> 35 See Mather et al. (1999) and Angelsen and Mikkonen (2005).

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