Many techniques have been attempted to control invasive weeds, from herbicides to biological controls to burning. On the Hawaiian island of Kaua’i, several non-native species of plants and animals have taken hold, but watershed managers are using high-resolution aerial mapping to locate and kill at least some of them. Australian tree fern, an ornamental plant imported to the island decades ago to plant at tourist resorts, is one of the worst. The fast-growing invader replaces native vegetation on which the island depends to trap water and recharge the aquifer.
Other invasive species—notably wild pigs, but also plants like kahili ginger and strawberry guava—have also gained ground on the island in a cycle that’s difficult to break. As this article explains, “The pigs rip up the ground while rooting about for food, speeding erosion on steep inclines. These invaders also trample level ground and compress the soil, preventing rain from percolating to the water table. All of this destroys the water-generating function of the native forest, which discharges hundreds of millions of gallons of water a day.” When it rains, less water reaches the aquifer and more runs off in the streams, causing yet more erosion.
Targeting only the invasive plants with herbicides amid this dense vegetation is difficult. The Kaua’i Watershed Alliance, consisting of several organizations including the Nature Conservancy, manages thousands of acres of land on the island and has been photographing the area from a helicopter, mapping it to an ever-finer resolution. From one-meter-resolution satellite imagery several years ago, the alliance now has maps with one-centimeter resolution. This allows accurate identification and targeting of different plant species. Herbicide is applied by helicopter in two ways: either from a dispenser underneath the craft that releases precision doses, or in pellets fired from a paintball gun from inside the helicopter. In three years, the alliance has treated 5,000 acres for Australian tree ferns using only 11 gallons of herbicide. You can read more on the program here.
Coming up on February 27 at Forester University: “Health and Safety Issues of an Aging Workforce.” Employees over the age of 55 are the fastest-growing group in the workforce. This webinar, led by Nellie J. Brown of Cornell University, explores the impending workplace age shift and what it means for your organization, including how you can identify current and future impacts of aging and any associated risks. Brown discusses the strategies and solutions available to meet the challenge of aging in the workplace, and how to implement these strategies to create an environment that supports your aging workers, maximizes their contributions, and minimizes your organization’s risk and vulnerability. Learn more at http://www.foresteruniversity.net/webinar-aging-workforce.html.