Brad Withrow-Robinson, Forestry & Natural Resources Extension Agent, Benton, Linn and Polk Counties.
In previous segments I argued that many people have too many trees in their young stands which may be costly and harmful to the long term growth of the stand. Most importantly, having too many trees at this stage can undermine common landowner objectives of growing attractive, longer rotation diverse forest habitats and can force landowners into shorter rotations than imagined.
While this suggests that people should think about planting fewer trees per acre in the future (a step deserving some careful consideration), it highlights the need for thinning in many existing young stands to correct overstocking at an early age. This may include your stand.
By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington & Yamhill Counties
Last week I traveled to sunny Eastern Oregon for the OSU Extension Forestry team’s annual planning meeting. To kick things off, our group spent an afternoon with Tom and Cindy Beechinor, who are active forest landowners, Master Woodland Managers, and dedicated Extension supporters in the Blue Mountains above the town of Milton-Freewater. We toured the family’s 640-acre property and learned much about how they care for their land and some of the challenges they face. Some observations: Continue reading →
By Amy Grotta, OSU Forestry & Natural Resources Extension – Columbia, Washington & Yamhill Counties
Early seral…it’s one of the biggest buzzwords in Pacific Northwest forestry these days. But what is it? Put simply, early seral refers to the first stage in forest development following any disturbance, including wind, ice, fire or logging. An early seral, or early successional community is made up of the first colonizers of a forest opening: grasses, other herbaceous plants and broadleaf shrubs. Continue reading →
“We’ve never left much on the ground in the way of dead wood…not during logging, but wind damaged, etc. Our thought has always been that these rotting logs increase the insects in the forest, both good and bad. Is this a valid concern and if so, where is the balance between bugs and wildlife?”
He raises a point worth exploring. While calling an insect “good” or “bad” is a matter of perspective, for the purposes of this discussion let’s assume that “bad” insects are those that cause economic or environmental damage, and “good” insects are those that don’t. The vast majority of insects that inhabit western Oregon forests fall into the “good” category…with a few notable exceptions.
One of these “bad” bugs that the e-mailer might have in mind is the Douglas-fir beetle. This time of year, the adult beetles are flying around in search of Douglas-fir trees where they lay their eggs underneath the bark. Their favorite targets are large diameter, freshly downed logs—or standing trees that are weakened from another cause (root disease, soil compaction, etc.). Through the summer and winter, the eggs hatch and the larvae grow as they tunnel around under the bark (this activity is what kills the tree). The following spring, they have become adult beetles, and they fly away in search of new homes. If they can’t find another weak tree or fresh log, they will go after a healthy tree.
Healthy trees can withstand a low-level Douglas-fir beetle attack, and in normal circumstances there are rarely enough beetles around to cause concern. The problem arises when the beetle population builds up and lots of them infest a healthy tree at once. When does that happen? In situations where there is a lot of freshly downed or damaged wood on the ground for them to target initially – like after a winter windstorm.
Here’s a true story for illustration.
In fall 2009, a landowner in the Coast Range was hit hard by beetle kill to his otherwise healthy, 100+ year old forest. Why? Here’s how we think this may have played out.
The stand is adjacent to a sawmill.
The big windstorm of December 2007 created lots of blowdown along the coast, though this particular stand was too far inland to be damaged.
Some of the coastal blowdown was not salvaged until summer 2008…too late, because Douglas-fir beetles had already found them during the spring.
The salvaged logs were brought to the mill, along with the beetle larvae living under the bark.
Then, in late 2008 the recession hit and the mill curtailed operations. The logs sat in the deck…and the beetles matured.
In spring 2009, they emerged and flew off to the neighboring stand, where they attacked the healthy, mature trees.
It was a sad situation, especially since the landowner had to cut more trees to avert further beetle damage, and in a poor market.
So, back to the e-mailer’s question: does retaining snags and downed wood for wildlife create a forest health risk? The take-home messages are these:
Most insects are not forest health risks.
In western Oregon, the Douglas-fir beetle (the “baddest” dead wood-inhabiting insect) only thrives in FRESHLY dead or downed trees. Once the snag or downed wood has been dead for more than a year, it is no longer a target. Instead, it will become inhabited by the dozens of “good” bugs that feed wildlife.
There needs a LOT of this fresh down wood to pose a forest health risk – like after a storm. According to Oregon Department of Forestry, a good rule of thumb is that fewer than 3 FRESH down logs/acre does not present a hazard.
After a windstorm or other stand-damaging event, yes, prompt salvage is important in order to prevent a beetle infestation. But, when scattered trees gradually die in a stand from other causes, it is hard to imagine when this would create a risky situation with respect to bark beetles. And during harvest activities, you can be strategic about how much dead wood is left behind, and in what conditions.
We appreciate it when readers respond to our blog posts. We like your e-mails, but you can also respond by commenting directly on the blog, where other readers can contribute to the conversation.
I recently was at a conference on “Wildlife in Managed Forests” sponsored by the Oregon Society of American Foresters and the Oregon chapter of The Wildlife Society. Speakers discussed current research on wildlife damage and wildlife habitat enhancement projects across western Oregon and Washington. There was far too much interesting stuff for this short article, so in this post I will focus on one recurring theme of the meeting. It’s one of the easiest and most effective ways to maintain a wildlife-friendly forest: retaining dead wood as snags (standing dead trees) or downed wood (on the ground). I’ll return to some other topics later.
Nearly 100 species of animals in Oregon (mostly birds) use snags. First, birds such as woodpeckers forage on insects living in these trees and then excavate cavities in them for nesting. Later, these cavities are used by other bird and mammals for nesting and shelter. Raptors such as hawks may also use snags as perches, from which they can prey on voles or other mammals that might damage seedlings.
With snags, the rule of thumb is “bigger is better” – smaller diameter snags will only be used by smaller animals and do not last as long. So if scattered trees die on your property, consider leaving them for wildlife, keeping safety in mind. Snags can also be created artificially during harvest. Mechanical harvesters can top trees up to 20 feet or so, and so can create a snag out of a tree with a defect down low but a merchantable top. The second best option, if you cannot safely cut the tree up high, is to fell the tree and leave the defective portion in the woods where wildlife will use it. Now it has become “downed wood.”
Just a few days after the workshop, I was out visiting with a landowner near Rainier. A small harvest had just been completed, and the logger had left a big, defective log alongside the unit (shown in photo below). The owner wondered, could it have been sold as a pulp log? Should she see if someone wanted it for firewood? I suggested that the log was already providing value, and probably more than what might have ended up in her wallet from these potential uses. Downed wood is used for cover, travel corridors, breeding spaces, and are especially important for amphibians such as newts.
The naturally regenerated alder in the background had come in after a harvest that had left little to no wood on the ground. The foreground will soon be planted back to conifers, which will take decades to reach a size that will provide a new source of snags or downed wood. By carrying over some downed wood like the log in the photo from one forest generation to the next, you can ensure some continuity of these wildlife-friendly habitat elements. Consider not disturbing down logs that are already in your forest – they are playing an important role, and besides, your equipment may take a beating if you try to move them or run them over!
Have you created or left snags or downed wood on your property? Do you have evidence of wildlife using these structures? I would like to create a photo gallery. Send me a photo of dead wood in your forest with a description of how it came to be or who you think is using it. If I get enough responses, I’ll share them all in a future article.
As a follow up to an article I included in last winter’s newsletter, here’s a story from OSU’s Terra magazine about some research on the effectiveness of beaver relocation projects. In theory, relocating beavers from areas where they are a nuisance to areas where they could contribute to habitat restoration could benefit all involved (including, presumably, the beavers themselves). Do relocated beavers stay put? Do they actually help create fish habitat in their new homes? Read the blog post, or listen to a short podcast.
Native turtle conservation is the subject of a presentation on Feb. 8 in Portland
Oregon Wildlife (Oregon Wildlife Heritage Foundation) invites you to learn about Oregon’s native turtles― the western pond and western painted― at a free presentation by Dan Rosenberg of the Oregon Wildlife Institute. The presentation will be held at the Ecotrust Building in Portland’s Pearl District. A reception begins at 6 p.m. The lecture at 6:30 p.m. Admission is free; registration is required. Register online at the Foundation’s website, www.owhf.org/discoveringwildlife.
Attendees will learn about the state’s two native turtle species and efforts to protect and enhance populations in the Portland area. The presentation includes information for landowners about voluntary conservation actions that can help native turtles. Like many of the world’s freshwater turtles, Oregon’s turtle populations are declining due to habitat loss, degradation of nesting areas by invasive plants, competition from invasive turtles, nest predation, and predation on young turtles by invasive aquatic species.
Both the western painted and western pond turtle are listed in the Oregon Conservation Strategy as species in need of help.
For more information or questions, contact the Foundation at (503) 255-6059. The talk will be held at the Billy Frank Jr. Conference Center of the Ecotrust Building in Portland’s Pearl District, 721 NW Ninth Avenue, Portland.
Last month I was fortunate to have the chance to tour the Chehalem Ridge Natural Area, a 1,100 acre property acquired last year by Metro near Gaston. It was a fascinating field trip led by Kate Holleran, who is responsible for directing forest management for Metro at Chehalem Ridge.
Kate described Metro’s management objectives, which include restoring oak woodlands through thinning and release from conifer competition; thinning the extensive, dense stands of young Douglas-fir to improve forest health, productivity, and forest structure; maintain the property’s extensive road network; and protect and improve fish and wildlife habitat. Kate hopes that Chehalem Ridge will be managed as a working forest, with revenues from product sales going back into forest management activities.
Chehalem Ridge is currently not open to the public except through guided tours. Luckily, Washington County Small Woodlands Association has arranged for a tour on August 27th. I look forward to seeing what develops at Chehalem Ridge in the coming years. I think it could be a great local resource to demonstrate forest management for multiple objectives.