"The data on total reduction of forest cover over Colombia and that on losses resulting from coca cultivation span different periods of time, so only rough comparisons of the two can be made. It is likely that several hundred thousand hectares of forest were cleared due to the direct and indirect effects of coca cultivation prior to 2000, before UNODC estimates from remote sensed data were available. Forest cover change in Colombia for the period 1990 2000 is estimated at 190,470 hectares per year. If this rate was assumed to have continued from 2000 to 2004, the total area deforested in those four years would have been 761,880 hectares, of which the 97,622 hectares of primary forest identified as converted to coca cultivations in this period would form 13%. As already noted, the actual of primary forest cleared due to coca cultivation is greater than the area being directly cultivated for this purpose, because of the other crops and activities of the farmers including the opening of roads and airstrips for transport of coca products."

Source

United Nations Office on Drugs and Crime, "Coca Cultivation in the Andean Region: A Survey of Bolivia, Colombia and Peru" (Vienna, Austria: June 2006), pp. 24-25.
http://www.unodc.org/pdf/ande…