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

May 23, 2013

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" , now more than 20 percent of the ships at sea, has demanded change. The 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 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 : dry-season water flows, carbon sequestration, timber and .

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).

Simonit and Perrings found that only 37 percent of the currently forested area positively impacts dry-season water flows, offering up roughly 37.2 million cubic meters of seasonal flow (equivalent to US $16.37 million in revenue to the Panama Canal Authority).

In parts of the watershed not currently under forest, they found that reforestation of areas with high precipitation rates, flat terrain, and soil types with high potential infiltration would enhance dry-season flows. However, they note that these conditions exist in less than 5 percent of watershed not currently under forest.

"Water supply is, however, only one amongst many ecosystem services affected by reforestation of the watershed," said Perrings, a professor in the School of Life Sciences in ASU's College of Liberal Arts and Sciences. "And the balance between services depends on the type of reforestation undertaken." Accordingly, the duo investigated two reforestation scenarios: natural forest regeneration and teak plantation.

"We found that if all existing grasslands were allowed to regenerate as natural forest, there would be a reduction in dry-season flows across the watershed of 8.4 percent, compared to 11.1 percent if reforestation took the form of teak plantations." In both cases, these conditions potentially pose a problem for the Panama Canal Authority. Even with water-saving advances in the new locks, the canal is expected to need 14 percent more water when the expansion takes full effect, and other options for securing dry-season flows are not cost-free. However, the Panama Canal Authority is not the only beneficiary of the watershed, and water is not the only ecosystem service supplied. "Both natural forest and teak plantations offer benefits in the form of carbon sequestration and timber products, among other things, and these should be weighed against any water losses," said Perrings.

According to their study, water losses from "natural" forest regeneration would be compensated by the value of in 59.6 percent of the converted area at current carbon prices. On the other hand, reforestation of existing grassland with teak (under sustainable forest management) would generate gains sufficient to offset the hydrological losses in all converted areas, regardless of the value of carbon.

The authors note that their study does not consider the value of land cover as habitat for wild fauna and flora. However, they say their results could help canal planners prioritize reforestation efforts. Knowing what to plant and where can reduce the negative impact of forests on dry season water flows, while providing other important ecosystem services.

Explore further: Scientists find ancient fossils in Panama

Related Stories

Reforestation efforts reshape Hawaii's soil hydrology

Mar 31, 2012

Starting with the arrival of Polynesian settlers in the fourth century, and peaking in the mid-1800s, the destructive forces of wildfires and pests and the grazing of feral pigs, goats, and cattle reduced the native forests ...

Recommended for you

Predicting bioavailable cadmium levels in soils

16 hours ago

New Zealand's pastoral landscapes are some of the loveliest in the world, but they also contain a hidden threat. Many of the country's pasture soils have become enriched in cadmium. Grasses take up this toxic heavy metal, ...

Oil drilling possible 'trigger' for deadly Italy quakes

20 hours ago

Italy's Emilia-Romagna region on Tuesday suspended new drilling as it published a report that warned that hydrocarbon exploitation may have acted as a "trigger" in twin earthquakes that killed 26 people in ...

Snow is largely a no-show for Iditarod Trail Sled Dog Race

20 hours ago

On March 1, 65 mushers and their teams of dogs left Anchorage, Alaska, on a quest to win the Iditarod—a race covering 1,000 miles of mountain ranges, frozen rivers, dense forest, tundra and coastline. According ...

UN weather agency warns of 'El Nino' this year

21 hours ago

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

Study shows less snowpack will harm ecosystem

22 hours ago

(Phys.org) —A new study by CAS Professor of Biology Pamela Templer shows that milder winters can have a negative impact both on trees and on the water quality of nearby aquatic ecosystems, far into the warm growing season.

User comments : 0

More news stories

Warm US West, cold East: A 4,000-year pattern

Last winter's curvy jet stream pattern brought mild temperatures to western North America and harsh cold to the East. A University of Utah-led study shows that pattern became more pronounced 4,000 years ago, ...

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

ESO image: A study in scarlet

This new image from ESO's La Silla Observatory in Chile reveals a cloud of hydrogen called Gum 41. In the middle of this little-known nebula, brilliant hot young stars are giving off energetic radiation that ...

First direct observations of excitons in motion achieved

A quasiparticle called an exciton—responsible for the transfer of energy within devices such as solar cells, LEDs, and semiconductor circuits—has been understood theoretically for decades. But exciton movement within ...

Patent talk: Google sharpens contact lens vision

(Phys.org) —A report from Patent Bolt brings us one step closer to what Google may have in mind in developing smart contact lenses. According to the discussion Google is interested in the concept of contact ...

Tech giants look to skies to spread Internet

The shortest path to the Internet for some remote corners of the world may be through the skies. That is the message from US tech giants seeking to spread the online gospel to hard-to-reach regions.