“The clear cut patches are plainly obvious from aircraft so is this just some kind of logging humor?” a user with the tag “daffish” asked on nwhikers.net.
“I couldn’t figure out why anyone would log that way,” user “vibramhead” responded on that site.
“I’m thinking it was an experiment in forest crop circles,” user “treeswarper” said on nwhikers.net.
The strange patterns certainly raise the question: Do bears play craps in the woods?
The answer to that question, for better or worse, is far less silly.
“That was a study that started in 1992, with the trees cut in 1996 and 1997,” said Jon Nakae, a forester at Gifford Pinchot. “The intent was to evaluate ecological aspects of green tree retention — doing clear cuts but leaving different densities of trees to see the effects on trees, birds, insects, mosses, lichens and other parts of the ecology.”
The study looks at forest recovery in clear cuts where different-sized groups of trees were left alone.
And the fact that the patterns look like dice? That’s an unfortunate side effect, Nakae said.
“The square design wasn’t really the intent,” Nakae said. “That pattern had more to do with the rigidity that the scientists wanted for their data. It was more to make things uniform and standard.”
Each square is 32 acres, so researchers can compare different types of cuts in a uniform space.
In the dice pattern that looks like a 2, 15 percent of the trees were left alone. In the pattern that looks like a 5, 40 percent of the trees were left. In another pattern that looks like you flipped the colors and rolled a 3, 75 percent of the trees were left. And each part of the study also has a full square where 100 percent of the trees remain.
Researchers from the Pacific Northwest Research Station, the Forest Service, the University of Washington, Oregon State and the University of Oregon all worked or are still working on the project.
The four patterns, along with some others that don’t look like dice, were replicated in six spots across the two states.
What researchers have learned so far is that leaving tree patches like the 5 dice — in five dense 2.5-acre circles with 40 percent retention — seems to be much more effective at restoring the ecology over time than leaving fewer circles, spaced like that of the 2 dice.
“It’s a long-term study,” Nakae said. “It’s designed to go for 100 years or however long it takes (for the forest to fill back in).”
Every year, the forest comes back a bit more in all of the cuts, he added.
Nakae has been involved in the project from the beginning. He helped pick the six spots for the study, which goes under the acronym DEMO, for “Demonstration of Ecosystem Management Options.”