As a Metro scientist, Kate Holleran sees nature's biggest challenges and most glorious surprises – and she has the muddy boots to prove it. Read her latest reflections on restoring the land protected by Metro's voter-approved Natural Areas Program.
By Kate Holleran, Metro Scientist
Conserving nature, one acre at a time
Lifting an old board off the ground at Chehalem Ridge Natural Area, my colleague Ryan Jones and I stared in delight: Three species of snakes had taken refuge under the wood. We found a beautiful tri-colored Western gopher snake (Pituophis melanoleucus), a rubber boa (Charina bottae) and a Western garter snake (Thamnophis sirtalis fitch) coiled up, each in its own corner. We were as surprised by our discovery as the snakes were to be discovered. After taking a few photos, we replaced the wood and had a great day in the forest of Chehalem Ridge, just 20 minutes from Hillsboro. The unsung hero of this story wasn't us scientists, or the gopher snake, or even the rubber boa – it was the wood.
One of the definitions for dead wood in the Merriam-Webster dictionary is "useless material." But that’s just a bad rap for the real stuff. From an ecological perspective, there’s no substitute for down dead wood.
Fallen trees and branches, small twigs, root wads and old logs play many roles in a healthy natural area. Fungi inoculate and begin to degrade the down wood, attracting insects that bore into the wood to lay eggs, which in turn attract foraging mice and shrews and bears and flickers, to name just a few.
This cascade of benefits to wildlife increases with the size and amount of down dead wood we leave in the forest. Small mammals and amphibians use down logs as pathways – allowing for faster or safer navigation through a chaotic forest. Yes, snakes find shelter under down wood, and so does the elusive Pacific giant salamander (up to a foot long). Down dead wood holds soil in place, soaks up and stores moisture, provides a nursery bed for seedlings and, as it degrades and disappears into the ground, feeds nutrients into the soil. That’s a lot of hard work for dead wood, and hardly the example of useless material.
The history of our natural areas includes agriculture, logging and development, all activities that remove wood from the land. Down wood is often too small and too scattered to provide all those benefits to wildlife, water quality and soil protection. As part of my restoration work, I look for ways to add wood back in: leaving fallen trees from thinning projects scattered across the site, or not burning slash piles created from clearing non-native species.
Only time will create the large live trees that become large down dead wood. In the meantime, any wood – even small wood – is good.