The role of nurse trees in mitigating fire effects on tropical dry forest restoration: a case study

The threat of fire is always a consideration when establishing a forest restoration program. Two wildfires occurred in 2006 and 2007 in an established dry forest restoration project in Puerto Rico. The original goal of the project was to determine differential growth responses of native trees under the nurse tree Leucaena leucocephala versus in open sites. Tree species growth, mortality and response to the fires were evaluated according to their leaf habit, successional status, and prefire tolerance to environmental conditions. Results showed that regardless of a species' leaf habit and successional status, trees attained greater height and lower mortality under nurse trees. In open sites, sprouting was the most common fire response and mature-forest and evergreen species had greater postfire survival than pioneers and deciduous species. Although nurse trees are typically used to help manage nutrient or light environments in reforestation projects, these trees also appear to provide a secondary benefit of limiting fire damage by reducing fuel load.