Gaining a New Perspective: Studying Forests from Space

Jennifer Hushaw | October 29, 2018 | Newsletters

Jennifer Hushaw Shakun

Applied Forest Scientist

For many years, if you wanted to know the condition of a forest or measure its defining characteristics, such as the types of trees and their size, the only real method was to venture into the field to observe and measure things first-hand. But over the past several decades, there has been a growing suite of new and improving technologies that allow us to observe, measure, and monitor forests from above—opening up a world of possibility for scientists, timber companies, and the conservation community.

Some of this technology involves specialized cameras and sensors that detect the amount and wavelengths of light that are reflected by the forest, which tells us all kinds of useful information. This includes everything from the types of trees and how fast or vigorously they are growing to the timing of seasonal events like spring leaf-out and the presence of stress from insect outbreaks or drought. In addition, there are other technologies, such as lidar and radar, that actively send out pulses of laser light or radio waves, respectively, and then detect the signal that is reflected back, which provides information about the size, shape, and three-dimensional structure of the objects below. All of these technologies can be mounted on planes or drones that fly over the forest canopy or on satellites that are launched into orbit around the Earth.

The week culminated in a day-long field trip to the Smithsonian Environmental Research Center where remote sensing and extensive field sampling are being used to study long-term forest change. Images from the field tour pictured here.

Remote sensing is the catchall term for this type of science and, while it is not a perfect substitute for on-the-ground measurement, it is a useful complement to traditional methods of forest measurement and it has some important advantages. In particular, it offers an ability to observe very large areas and places that are remote or difficult to access, and to do so at a lower cost, in many cases, than surveying the equivalent area in person. In fact, remote sensing data is becoming an important component of an ongoing project called the Resiliency Assessment Framework (RAF), which falls under the umbrella of Manomet’s Climate Smart Land Network (CSLN). The RAF is an effort to develop simple and cost-effective metrics for monitoring forest change that may be related to or driven by a changing climate. It includes both on-the-ground measurements that CSLN members can implement on their own land, as well as a picture of the regional context developed using the U.S. Forest Service’s Forest Inventory and Analysis (i.e. our nationwide forest census) and remotely sensed data.

Earlier this month, I immersed myself in this topic at a conference at the University of Maryland called ForestSAT. This meeting is held every other year at various locations across the globe and brings together hundreds of scientists from countries all over the world who are focused on the “application of spatial analysis and remote sensing technologies for forest monitoring, modeling and description.” A series of more than 240 scientific talks covered the latest techniques, data sources, and technologies. A variety of stakeholders are using this information—researchers are using these data to study forests, non-profits are using the information to monitor deforestation, and governments are using the technology for monitoring and planning related to their forest resources.

The Climate Services program will be leveraging this evolving science to help our CSLN members gain a better understanding of how their forests are changing and potentially detect early warning signs of forest stress that they can address through management. Forests have a critically important role to play in limiting the severity of climate change. Through the CSLN, Manomet is building partnerships and applying the latest technology to keep our forests green and healthy.