Hawaii's non-native tree plantations were originally intended for timber production and to conserve the islands' top soil. In the early part of the 20th century, ranches and plantations producing sugar cane and pineapple covered much of Hawaii's agricultural areas. But years of these practices led to increased soil erosion, and fast-growing non-native trees were planted to hold the soil in place and to preserve water by preventing runoff. At the time, however, the importance of biodiversity and the dangers of exotic species weren't as clear as they are today.
Especially with climate change rapidly changing many ecosystems, Sack says, it's vital that land management plans recognize and integrate the fact that water use by plants can affect the clean water supply.
"When making decisions to restore a native forest or preserve or establish a plantation, we need to do a more detailed valuation that includes the cost of water they're using," he says. "There are a lot of reforestation projects underway to take up carbon dioxide from the atmosphere, where people are prioritizing fast-growing trees. But we shouldn't let alien plants sweep over native forests. Our findings make a clear case that we
|Contact: Christine Buckley|
Ecological Society of America