OSU researchers strive to verify Aerial LiDAR findings with extensive manual sampling.
You’re climbing an eight-meter scaffold. It’s shaking. You’re scared of heights. Your knees are weak. Looking down, you see a clear view of the volcanic soiled forest floor. It’s far away. With a 20-foot pole saw in hand, this is how researcher Adam Burke begins his day — with hopes of validating Aerial Light Detection and Ranging (LiDAR) of lodgepole pines.
Adam Burke, a master’s student in the forest engineering and resource management program at Oregon State University, is analyzing the effectiveness of the measurements of Aerial LiDAR for the lodgepole pines that grow near Mt. Bachelor.
Aerial LiDAR is a big radar machine attached to an airplane, which sends pulses of light below it as it flies over a certain area of forest. Aerial LiDAR measures and picks up the volume of tree canopies. From the data collected, a map of the total volume of trees within a given area is then generated.
Burke seeks to understand how much biomass — aka, stuff — is truly represented within the lodgepole pine forest, due to the odd system in which it is located.
Lacking organic matter and essential nutrients, the volcanic soil on the Pumice Plateau located high above in the Deschutes National Forest offers a unique and difficult system for trees to grow. Surrounded by volcanic ash that has been turned into rock, the lodgepole pine is a species of tree with much resilience that has forced its way into being the climax species in the area.
The U.S. Forest Service conducted an Aerial LiDAR survey of the lodgepole pines in this forest stand (region) in 2011.
“It’s clearly a lot faster to fly an airplane over a forest and generate estimates of how much volume there is,” Burke said. “It’s a different thing to go out as we did this past summer and physically sample each tree.”
Burke’s research aims to provide the forest industry a better knowledge of how much volume of lodgepole pine there is, to better estimate fire risks and to gain a better idea of the value of the forest, according to Burke.
Burke and his research team spent the entire summer sampling 33 lodgepole pine trees, removing 36 branches from each tree.
The researchers are looking at all the living material of the tree — its biomass — not just the branches. They collected the needles, foliage, cones, flowers and the stem of the tree as well.
“Collecting the biomass entailed hauling and setting up a huge scaffolding daily that measures eight meters high, cutting all of the parts off the tree, bagging and tagging them all, taking the scaffolding down and doing it all again for the next tree — it’s a lot of work,” Burke said. “I don’t like heights.”
Burke’s hands-on and laborious research seeks to validate the data estimates of the Aerial LiDAR in 2011.
“When the LiDAR from their airplane transects, they can say, ‘this stand has X volume in it,’” Burke said. “I’m coming into the forest with my team, and we’re actually measuring the trees in a stand where the LiDAR collected its data. … For this we can say, yes, the volume that the LiDAR is saying is correct, based off of the researchers recent measurements. Or, based off of our measurements — the LiDAR data is not correct.”
Researchers care about the effectiveness of LiDAR and the lodgepole pines with regard to the potential of cultivating a market for lodgepole pines, which does not exist yet, according to Burke.
“There isn’t a market now, but potentially in five or 10 years, there could be a good industry for the biomass market of the lodgepole pine,” Burke said. “This is why validating LiDAR is so important — using Aerial LiDAR to measure the forest is more efficient.”
According to Burke, the demand for biomass is going up.
“In this industry, they take a tree, run it through a chipper, and then the chips are sold in order for people to make steam energy or to burn,” Burke said. “The problem is that there is not enough value in lodgepole pine right now in order to justify going in and removing the trees, then selling them for biomass,” Burke said.
Ultimately, researchers hope the validation of LiDAR will inform land owners on how to best manage their lodgepole pine forests in eastern Oregon.
Burke aims to reach his findings within this research later in the year.