Perspective on the control of invasive mesquite trees and possible alternative uses

Abstract: Mesquite trees continue to invade forests and range lands in many countries across the world. The cost to remove these trees is staggering. In Texas, landowners spent $25 million over a 10-year period to clear 300.000 ha of mesquite trees, a fraction of the 22 million ha of Texas land affected by this invasion. Estimates are that the mesquite continues to negatively impact one to two percent of additional land in selected counties each year in Texas. However, the problem is not unique to Texas, but rather to the 44 species of mesquite trees, belonging to the genus Prosopis found in the pea family (Fabaceae), introduced across the southern United States, South Asia, Africa, the Middle East, South America, and the Caribbean. In response, researchers are searching for economically viable uses for harvested trees and seeds to provide an alternative to the high cost of removal. If viable uses for harvested mesquite trees and seeds are found, then sustained pressure will limit and ultimately reduce the negative impact from these invasive trees. One key factor to controlling this invasive species is to find economically and environmentally sustainable uses to help pay the costs of removal or perhaps make removal less necessary. Traditional uses of mesquite are as a building material, as a source of food for both animals and humans and as wood for charcoal. Emerging uses of mesquite are new applications as a biofuel and as a bio-filter medium for water. Moreover, forestry land management of mesquite has adapted to include the tree as a component of hunting lands. New control methodologies and technologies are based on an increased understanding of mesquite growth patterns, using recommended practices that reduce control and eradication costs while improving the efficiency of land management. Previous land management practices have proven that excessive application of herbicides, physical removal of mesquite trees, or human-induced brush fires, if not carefully planned, only worsen mesquite infestations. The growing problem of mesquite land management provides an opportunity for continued research into novel ways to utilize mesquite biomass, of both wood and seed pods.