It's a bird, it's a plane, it'sa robot in the trees? At the Wind River Canopy Crane Research Facility in Carson, WA, scientists have deployed a briefcase-size robot that rolls along a 50-meter-high cable strung between trees. Built by electrical engineer William Kaiser's team at the University of California, Los Angeles, the robot comes equipped with environmental sensors, a still camera, a processor, batteries, solar cells, and a wireless link to the Internet. Programmed to patrol the forest canopy, the high-rolling robot maps changes in temperature, humidity, and sunlight. The researchers plan that in the future the device will also monitor carbon dioxide concentration, while documenting the growth of individual leaves and branches-measurements that were previously hard to make. The National Science Foundation is footing the bill, to pinpoint how much carbon and heat the trees absorb from the atmosphere; this could help researchers predict the climatic effects of harvesting and deforestation. Deployments are planned in three other forests by springtime, says Kaiser.