Fausto O. Sarmiento, Larry M. Frolich
Mountain Research and Development 22 (3), 278-287, (1 August 2002) https://doi.org/10.1659/0276-4741(2002)022[0278:ACFTL]2.0.CO;2
KEYWORDS: Tree line, mountain agriculture, biodiversity drivers, restoration ecology, Tropandean landscapes, páramo, tropical Andes, Ecuador
We challenge the paradigm of natural tree line formation in the equatorial Andes with an alternate view that incorporates the human dimension. We present both direct and indirect evidence of anthropogenic influences on cloud forest tree line location; these human influences should be incorporated in definitions of Andean tree lines as (1) the extensification of grassland for grazing and potato cultivation for the upper limit, and (2) the intensification of the agricultural frontier, fuelwood gathering, and timber extraction for the lower limit. Although we do not claim to fully debunk the prevalent paradigm of tree line dynamics (which is descriptive, depends on the natural sciences, and sees tree lines as physically controlled), we hope to achieve increased recognition for a challenging alternate view of tropical tree lines as functional, resource-use dependent, and human-driven. Management plans and overall tropical montane cloud forest conservation strategies need to consider this new perspective and incorporate a proactive and assertive approach toward restoration of Andean forests in a way that will encourage landscape diversity in tropical mountain ecoregions.