Flying 1,500 feet above the forested lands of Oregon, forest officials worked quickly to identify and document tree mortality.
A joint state and federal effort, both U.S. Forest Service and Department of Forestry officials fly over most forested land in the state without regard to ownership. They have about 20 to 30 seconds per square mile to detect the current impacts of defoliation, mortality, insect damage and disease-causing organisms.
With red, scraggly tree tops, drought-affected Douglas firs are more susceptible to being impacted by bark beetles, wood boring beetles and diseases like root rot.
“Of course when a tree is stressed, it doesn’t grow as well and it’s also not able to resist other environmental factors like insects and diseases,” said Mike Harris, vegetation program manager for the Umpqua National Forest U.S. Forest Service. “It places them kind of in a precarious situation and now a lot of people are seeing branches dying off on especially their Douglas fir trees.”
The aerial observers attach a drought note to any observation they think are drought-related.
The preliminary results for the 2016 aerial survey were released in late September, while the finalized data is expected to be released in November.
This year, they found increased levels of flat-headed fir borer killing Douglas fir in Southern Oregon, including Douglas County, bear damage to plantation Douglas firs and die-off of Port Orford cedar from root disease. They also noted the branch flagging of red fir due to cytospora canker that’s been seen in previous years.
The ability to record this information has improved since the surveys began in 1947. Now, the plane flies on a grid pattern at 100 miles per hour while each observer looks out for two miles, recording what they see with maps on tablet computers.
“It’s partly an artistic effort and partly a scientific effort,” said Bill Schaupp, an entomologist with the U.S. Forest Service who was an aerial surveyor for 20 years. With the tablets, they’re able to draw on graphic maps and take aerial photography.
The observers also incorporate different information, including the previous year’s results and the location of specific species of trees.
Anything appearing mysterious or unknown gets coded so they can come back and take a closer look from the ground.
In addition to the general survey, the observers conduct several special surveys to show a variety of other issues, from bark damage by bears to diseases like swiss needle cast and sudden oak death.
Though each specific survey is limited, the record accumulates over time to show trends.
“It allows us to provide information to people on the ground for a wide variety of uses with a view that isn’t attainable any other way, and it’s very inexpensive compared to other remote sensing techniques,” Schaupp said.
After a dry summer preceded by record droughts in 2013 through 2015, many of Oregon’s conifer trees have been feeling stressed, facing foliage loss, dead branches, dead trees and tops.
Keith Waldron, a stewardship forester for the Oregon Department of Forestry in Roseburg, said there’s a lot of tree die off from last year.
“A lot of times we won’t see the effects of the drought until late winter or early spring, but last year was dramatic enough that we saw early die off,” Waldron said.
He said though 2016 has been a pretty dry year, it wasn’t as bad as 2015.
Marty Amos, woodlands assistant forester for Douglas County, said the die off seems to be very wide spread across all age classes of trees and the lower valley areas have been impacted more so than the foothills of the Cascades.
“Our soil type seems to be a little poorer, less suited to conifer growth, and shallow roots run out of nutrients quicker,” Amos said.
Some stands in the Umpqua National Forest are experiencing these symptoms, especially around the Tiller area in the southern part of the county.
“It seems perhaps to have impacted the trees at lower elevations a little bit more than higher elevations,” Harris said.
Harris said he thinks this rainy fall season will help to alleviate the effects of the summer’s dry conditions.
“The best thing that we perhaps can do is work to give individual trees enough growing space so they can have adequate moisture and nutrients, it helps to reduce stress on the trees,” Harris said.
To view the results, visit the aerial survey website at www.fs.usda.gov/goto/r6/fhp/ads.