A Lidar’s-Eye View of How Forests Are Faring
Excerpt: Success in Yosemite is driving the wider use of lidar surveys to support forest health and wildfire resilience, study wildlife habitats, and monitor water resources. Building the perfect campfire requires the right mix of ingredients: plenty of kindling, a spark to ignite it, and large, dry logs to keep the fire burning strong. Unfortunately, fire suppression strategies adopted long ago—combined more recently with severe droughts and climate change—have created this same mixture writ large across many of the dry forests of the western United States, such as those in Yosemite National Park and elsewhere in the Sierra Nevada. ...Despite their destructive power, fires are natural phenomena in many forests, where they are essential to the biomes’ long-term health. Decades of field-based studies have built the field of fire ecology and have informed nuanced views of fire as both a threat and a restorative process. ...in the 1960s, fire ecology research at the University of California, Berkeley shined a light on the connection between regular fires and forest health .... ...areas burned by fires under nonextreme weather conditions ultimately became more resilient and resistant to future burning. ...forest managers in Sequoia and Yosemite national parks in the Sierra Nevada of California were among the first to introduce prescribed burns and to allow lightning-sparked wildfires to burn ...as part of a fire benefit program. In doing so, they sought to return these forests to a healthy cycle involving frequent fires that had existed for centuries before managers first sought to suppress all fires in the 19th century. ...Scientists’ ability to study Yosemite’s forests both on a broader scale and in more detail began to change in 2010. From 2010 to 2011, Watershed Science (now NV5 Geospatial) used its airborne lidar instruments to image and measure a total of 64,800 acres (26,200 hectares) of Yosemite National Park’s forests, .... These lidar data—collected at a high density of about 100,000 measurements per acre (247,000 per hectare) across the full study area—provided a census of the 3D structure of vegetation and the ground below.…