potential of agroforestry to reduce atmospheric CO 2 , including reducing the
level of forest loss. They note that “direct evidence of this potential is limited,
but one research study indicated that a low input agroforestry system, involv-
ing the rotation of acid-tolerant crops, produced agricultural products on a
single hectare equivalent to the volume normally produced on 5 to 10 ha
under slash-and-burn agriculture,” (53) citing Sanchez and Benites (1987).
Later in the article they use an average, 7.5 ha (now citing Sanchez 1990), to
conclude that by establishing 1 million ha per year of agroforestry, 7.5 million
ha of forest would be saved.
Dixon (1995) assesses agroforestry in relation to greenhouse gases and uses
Sanchez and Benites (1987) to calculate reduced carbon emissions from agro-
forestry: “If it is assumed that in low-latitude nations the establishment of one
hectare agroforestry can provide products that would otherwise require 5 ha
of deforestation...and that 2 × 106 ha of new agroforestry systems are estab-
lished annually...then the amount of low latitude forest potentially con-
served ranges up to 10 × 106 ha (108).” Dixon et al. (1993) make a similar
unqualified claim: “Sanchez and Benites estimated that 1 ha of agroforestry
could offset 5–10 ha of deforestation.” (164) Finally, in a classic text on agro-
forestry, Young (1997) uses Dixon (1995) and the 1:5 ratio, although he is
more modest about the potential of agroforestry: “An optimistic but plausible
establishment of 1 Mha of new agroforestry systems annually could therefore
potentially reduce the need to clear 5 Mha of forest a year, compared with
actual current clearance of 15 Mha.” (257)
In short, this is the story about how a study on yield differences (not
impact on deforestation), comparing shifting cultivation and different low-
input production systems (not agroforestry) in one particular location in Peru,
has been used to make global predictions about the impact of agroforestry on
deforestation.
It raises a number of questions. How representative is the Peruvian case
study for the tropics? Are farmers really giving up forest-clearing activities
when adopting agroforestry or other agricultural systems, such that their
income is kept constant? How will widespread adoption of agroforestry affect
markets, and what effects will this have on deforestation? Will successful agro-
forestry adoption attract more migrants, and will this increase the pressure on
forests? These questions are central to this chapter.
Typical Cases of Agroforestry Adoption
Technological progress simply means getting more physical output for the
same amount of inputs (or the same output with less inputs). Taking a
dynamic perspective, diversification of a cropping system so that total output
from different products remains more stable over time (reduced downside
risk) and measures that increase the longevity (sustainability) of a system
90 II. The Ecological Economics of Agroforestry