Skip to Main Content
U.S. Forest Service
Caring for the land and serving people

United States Department of Agriculture

Home > Search > Publication Information

  1. Share via EmailShare on FacebookShare on LinkedInShare on Twitter
    Dislike this pubLike this pub
    Author(s): Brett T. Wolfe; S.J. Van Bloem
    Date: 2012
    Source: Forest Ecology and Management. 267:253-261.
    Publication Series: Scientific Journal (JRNL)
    Station: International Institute of Tropical Forestry
    PDF: Download Publication  (1.04 MB)


    Throughout the tropics, non-native grasses invade, dominate, and persist in areas where subtropical and tropical dry forests have been highly degraded. In Central America and the Caribbean Islands, forests that regenerate in grass-invaded areas are generally composed of one to a few tree species, usually of the Fabaceae family and often non-native. We investigated the ecological factors that drive these successional patterns in southwestern Puerto Rico, where African grasses dominate extensive areas that are maintained by fires. The non-native legume tree Leucaena leucocephala commonly establishes in these areas and forms persistent, mono-dominant stands. We planted 455 saplings of 13 native tree species and Leucaena in native forest understory and in grass-invaded areas that were either subjected to or protected from prescribed fires 4 months later. We measured growth and survival to test the following hypotheses: (1) saplings of native species are suppressed in grass-invaded areas compared to the forest understory, (2) Leucaena saplings outperform native species in grass-invaded areas, but not in the forest understory, and (3) Leucaena saplings are less susceptible to wildfires than native species. After 20 months, 50%, 40%, and 3% of native saplings survived in the forest, unburned-grass, and burned-grass treatments, respectively. Over the same period, 90%, 80%, and 25% of Leucaena survived in the same treatments. The fires immediately killed 65% of native saplings and 50% of Leucaena saplings. The majority of unburned native saplings died during a seasonal drought, when high irradiance and reduced soil organic matter content likely led to higher mortality in grass-invaded areas than in forest understory. Native species’ growth was low in all treatments, yet diameter growth was slightly higher in the unburned grass than the forest understory. Leucaena saplings grew faster than the native saplings in all three treatments, especially in the unburned grass. Slow growth and high mortality of native saplings in grass-invaded areas contribute to the dominance of Leucaena in forests that regenerate on these sites and suggest that Leucaena may play a beneficial role in dry forest restoration in the Caribbean.

    Publication Notes

    • We recommend that you also print this page and attach it to the printout of the article, to retain the full citation information.
    • This article was written and prepared by U.S. Government employees on official time, and is therefore in the public domain.


    Wolfe, Brett T.; Van Bloem, S.J. 2012. Subtropical dry forest regeneration in grass-invaded areas of Puerto Rico: understanding why Leucaena leucocephala dominates and native species fail. Forest Ecology and Management. 267:253-261.


    Guanica Forest, Fire, Pennisetum ciliare, Novel ecosystems, Soil organic matter, Restoration

    Related Search

    XML: View XML
Show More
Show Fewer
Jump to Top of Page