Laser sensors spot trees with larch disease

April 6 (UPI) -- Researchers are using laser sensors to locate trees threatened by deadly larch tree disease.

Scientists at Leicester University partnered with aerial mapping company Bluesky to conduct a series of laser scanning surveys, or LiDAR surveys, in England and Scotland.

Larch tree disease is caused by the fungus-like pathogen Phytophthora ramorum. The disease can affect a variety of tree and plant species. In Britain, the pathogen has proved particularly deadly to Japanese larch trees -- hints the name. In the United States, particularly in Oregon and Washington, the disease is called sudden oak death, named for its most common victim.

The pathogen was first identified in Britain in 2002 and has since infected several high-profile forests, including Epping Forest and the Forest of Dean.

"Invasive tree diseases pose a huge threat to Britain's forestry," Heiko Balzter, director of Leicester's Centre for Landscape and Climate Research, said in a news release. "Diseases like Dutch elm disease and sudden oak death can wipe entire tree species from our landscapes within a few years. Climate change increases the risk of new tree diseases spreading across the U.K."

Researchers say Britain's forests are increasingly susceptible to diseases carried by invasive species. Tracking disease using LiDAR can help conservationists and foresters limit the damage of invasive pathogens before the disease spreads.

"While the use of LiDAR in forestry applications has become more common, its use to identify individual trees affected by diseases has, until now, been underutilized," said Chloe Barnes, a postgraduate researcher at Leicester's geography department.

LiDAR sensors measure canopy height across surveyed forests. Algorithms developed by Leicester scientists pinpoint anomalies among the canopy. Trees affected by Phytophthora ramorum suffer defoliation and dieback, leading to unusual dips in canopy height.

Researchers shared the results of their aerial surveys in the journal Remote Sensing.