Conversion of anthropogenic savanna to production forest through fire-protection of the forest-savanna edge in Gabon, Central Africa

Tropical moist forest is being destroyed at the rate of 11 million hecares per year: much of which degrades into fire-maintained savanna or low-productivity pasture. Greater economic and ecological benefits can be realized from much of this land if it can be converted into more productive secondary forest ecosystems. This study was conducted to deterimine if anthropogenic savannas could be converted into production forest through relatively inexpensive protection of the forest edge by plowing the soil with an agricultural tractor in highly-degraded (Ancient) and less-degraded (Nascent) savannas on the coastal plain of Gabon, Central Africa. After three years of protection, vegetation surveys revealed rapid colonization of Nascent savannas by 45 species of tree seedlings. Ancient savannas also experienced colonization by tree seedlings, but at a much lower rate. Analysis of soils determined that Nascent savannas have 5 times more calcium and magnesium and higher organic matter than Ancient savannas; indications of their less-degraded nature. Protection of the forest-edge from fire can be an effective, low-cost method of converting anthropogenic savannas into production forest through natural regeneration. The rate of conversion can be maximized by focusing on less-degraded sites to capitalize on more abundant seedling recruitment and higher ecosystem nutrient stocks, but even highly-degraded sites may be reclaimed with additional management. (C) 1997 Elsevier Science B.V.