The Nature Conservancy has started testing a remote sensing technology on Kaua'i that it says could be a major advance in the fight against invasive plant species in Hawai'i.

"I honestly think this could be the biggest technological breakthrough for weed management and monitoring in Hawai'i, or anywhere else, in the last decade," said Trae Menard, the Nature Conservancy's Kaua'i program manager, in a statement.

Under a contract with the conservancy, the firm Resource Mapping Hawai'i has developed imaging technologies that will allow conservation officials to sit at computer screens and recognize the major weeds in their areas from images taken from a plane instead of having to hike over all that terrain.

The system uses natural light and multi-spectral imaging, and can highlight Australian tree fern, miconia or strawberry guava plants and other weeds in a remote forested area.

On a clear day, the images are so detailed that individual leaves on some trees can be identified, the conservancy said. The system has a three-dimensional capability that calculates the heights of individual plants. Multispectral sensing allows a computer to search the images for specific kinds of plants. The cost is a few dollars per acre over large areas, officials say.

The conservancy, using private funds as well as state and U.S. Fish and Wildlife Service money, has allocated $400,000 for a pilot project to map 80,000 acres of Kaua'i forested land that it oversees as coordinator of the Kaua'i Watershed Alliance.

Dana Slaymaker of Resource Mapping Hawai'i developed the technology for the conservancy.

Slaymaker and Resource Mapping Hawai'i pilot Jimmy Ray Hoffert have installed the system in Hoffert's single-engine Cessna 182 at Lihu'e Airport.

The plane flies at about 2,000 feet with three specialized cameras peering through an opening in the aircraft's belly. One camera collects imagery in green, red and infrared wavelengths. A particular kind of plant will typically give off light in a specific pattern, which a computer can recognize. If you plug in the characteristics of a koa tree, the computer can use the imagery to locate all the koa trees in the landscape, the researchers say.

The other two cameras shoot in natural color and in great detail. The shape of individual trees can be identified.

As the plane flies over the landscape, a GPS device tracks the location of every image — so conservation workers can later go to the exact spot — perhaps to remove an invasive plant.