Reforestation study shows trade-offs between water, carbon and timber

EurekAlert: More than 13,000 ships per year, carrying more than 284 million tons of cargo, transit the Panama Canal each year, generating roughly $1.8 billion dollars in toll fees for the Panama Canal Authority. Each time a ship passes through, more than 55 million gallons of water are used from Gatun Lake, which is also a source of water for the 2 million people living in the isthmus.

However, the advent of very large "super" cargo ships, now more than 20 percent of the ships at sea, has demanded change. The Panama Canal is being expanded to create channels and locks three times larger than at present, leaving the authority to consider how best to meet the increased demand for water. One proposed measure is the reforestation of the watershed.

To help planners and policy makers understand the effects of reforestation, ASU scientists Silvio Simonit and Charles Perrings studied the effects of reforestation on a 'bundle' of ecosystem services: dry-season water flows, carbon sequestration, timber and livestock production.

Published this week in Proceedings of the National Academy of Sciences (PNAS), their study – "Bundling ecosystem services in the Panama Canal Watershed" – examines precipitation, topography, vegetation, and soil characteristics to model on-site and off-site effects of several reforestation options.

"The Panama Canal watershed is currently being reforested to protect the dry-season flows needed for canal operations. We find however that reforestation does not necessarily increase water supply, but does increase carbon sequestration and timber production," said Simonit. "Our research provides an insight into the importance of understanding the spatial distribution of the costs and benefits of jointly produced services." Simonit, a member of ASU's Ecoservices Group co-directed by Perrings, is part of a collaborative research partnership between ASU and the Smithsonian Tropical Research Institute (STRI). He is also a post-doctoral fellow on the National Science Foundation-funded research coordination network: Biodiversity and Ecosystem Services Training Network (BESTNet)....

The Gatun Locks at the Panama Canal, shot by Stan Shebs, Wikimedia Commons, under the Creative Commons Attribution-Share Alike 3.0 Unported license