Determinants for Successful Reforestation of Abandoned Pastures in the Andes: Soil Conditions and Vegetation Cover

Background

This article compares the growth of native and exotic species seedlings planted in abandoned pasture and among brachen ferns and shrubs in Andean Ecuador over three years.

Research Goals & Methods

The species (native: Alnus acuminata, Cedrela montana, Juglans neotropica, Heliocarpus americanus, Tabebuia chrysantha, exotic: Pinus patula and Eucalyptus saligna) were planted in a block design in the different successional stages and in plots with and without above-ground weeding.

Conclusions & Takeaways

Alnus acuminata had the greatest height growth of the native species and was competitive with Eucalyptus saligna. The species that grew the best in pasture were mostly early-successional (light demanding) while the mid-successional species (H. americanus, C. montana, J. neotropica) grew in bracken fern, and T. chrysantha grew best in the shrubs. Bracken fern sites were higher in Mn and N and lower in P than the other sites. For T. crysantha and H. americanus, weeding improved growth while for C. montana, weeding reduced growth (likely due to desiccation from the shade reduction). Authors conclude that soil heterogeneity (with regards to Mg, Mn, and P) affected growth of E. saligna and A. acuminata, and that small-scale variation in the soil conditions (nutrient composition) make difficult the establishment of generic site index values for reforestation and plantations (as is commonly done in the temperate zone).