Making of: Experience the Redwoods Project
Have you ever wished you could fly above the tree tops like a bird?
On August 8th, Evergreen Professor Mike Ruth and PropagationNation accomplished just that. But instead of trying their hand at metamorphosizing into avian creatures, the team employed a 21st Century approach utilizing a lime green Mavic 2 Pro drone to capture spatially accurate aerial imagery. Their goal: document a Redwood stand planted
at the Port Blakely tree farm in Olympia, Washington. The results of this exciting mission were organized into a visual StoryMap featuring aerial video, interactive 3D mapping, and carbon sequestration analysis. Explore the StoryMap here, and read on to learn about its making:
On a hot Tuesday afternoon, the team was welcomed by a Port Blakely forester at the gate of the tree farm. The forester courteously led them down a winding, dirt road lined with understory plants and Himalayan blackberries coated in summer drought-induced dust sent airborne by the passing vehicles. They drove by patches of Douglas firs, an otherwise common hardwood in an ecosystem cultivated for timber resources. When the trees suddenly got taller, more vibrant, with bark tinged rust red, it was clear they had arrived at the most unusual part of the farm, and their ultimate reason for visiting.
30 years ago, the previous owners of the land had planted a stand of hundreds of Coast Redwoods (Sequoia sempervirens). Inherited by the farm soon after, the
trees were incorporated into the business plan. The helpful forester informed the team that they were likely to harvest the Redwoods at year 50. While the trees were still standing, the team wanted to include the stand in their larger mission of documenting and studying Redwoods planted across the Pacific Northwest.
As they walked into the planting, the Redwoods towered magnificently above the crew in a neat grid pattern of straight-backed trunks shooting skyward, obscuring the summer sun with an umbrella of saturated blue-green needles. The floor beneath their feet was cushioned by a thick blanket of burnt sienna needles shed over decades from the canopy. The group walked until they reached a sprawling hay field. Absent of trees, the field was oppressively hot, but the open area provided a perfect spot from which to launch the drone.
Before takeoff, Ruth dropped several placards across the area to be mapped. These placards functioned as Ground Control Points (GCPs) whose precise GPS coordinates were documented utilizing a high-accuracy Juniper Geode in order to “correct” the coordinates of the captured drone imagery. By employing this method, the error in the subsequently created maps was reduced to a minimal 1.26 feet.
Once the placards were positioned and recorded, Ruth launched the Mavic 2 Pro above the canopy, revealing a rolling landscape of healthy green treetops. The Redwoods’ triangular apices pierced the atmosphere below the drone, distinguishing themselves to us amongst a sea of green. Over the course of an afternoon, Ruth flew an ox-plow mission and a cross-hatch mission, capturing a total of 340 images.
Back in air conditioning, PN contractor and Evergreen graduate student Caroline Slagle stitched together these images in mapping software to form 2D and 3D renderings of the stand. She created a True Orthomosaic and Digital Surface Model (DSM), which allowed her to identify about 429 Redwoods. To develop a detailed 3D map, she created a DSM textured mesh and 3D textured mesh, allowing her to measure the height of a periphery tree at 83 feet tall. Utilizing Sillett et al.’s updated 2019 second-growth forest equation, Slagle estimated 820.29 kg of carbon (nearly a metric ton!) had been sequestered so far by the stand. The almost 3.75 acres of Redwoods have the capacity to sequester up to 3,337.5 metric tons if allowed to become old growth. A visual analysis of Slagle’s mapping is provided by her StoryMap.
The Port Blakely Redwood stand is a ruby-red example of the potential Redwoods have to thrive once again in the Pacific Northwest as carbon-sequestration powerhouses. With a warming climate returning the region to pre-Ice Age temperatures, Redwoods will continue to find more of their ancient habitat in Washington as they lose their current habitat in California. A map of the Redwood fossil record indicating potential future habitat is provided for exploration in the StoryMap.
PropagationNation is on a mission to document all the Redwoods planted in Washington State in order to monitor their health, inform research, and record their impact to support their assisted migration northward. With community support, PN can paint the Northwest with Redwoods.
For now, the team is moving on to document another Redwood planting on the coasts of Hood Canal utilizing MultiSpectral Imagery. Stay tuned for our next StoryMap!
If you are interested in this project and helping us to continue making cool features like this, please consider donating to PropagationNation. Every dollar you give goes towards bringing redwoods to the people!