Monday, October 6, 2008

Forest field trip - visit to a commercial thinning, one year later

We spent the day on a field trip organized by the Washington State University Extension. We visited a 120-acre thinning that was done last year. The object was to observe the condition of the stand today, and learn about their low-impact logging and options for post-treatment.

The owner of 240 acres wanted to clear out old skid trails and thin about half of their property. Their neighbors each own 20 acres, and each wanted to thin about 10 acres. John Malone, a local consulting forester, worked with the three owners. They hired a local logging company with equipment for skyline logging, although most of the job was done with ground skidding.


Top - Wildlife biologist Jim Bodoff with WSU's Andy Perleberg and forester John Malone.

Below - Forest fire ecology expert Dick Schellhaas.

The property looked pretty good for a logging operation. We walked past some slash piles (re-piled because they didn’t burn well the first time) and stood in a stand of mixed P-Pine and D-Fir. There was very little slash on the ground, and no evidence there of excessive damage along skid routes. Fir limbs were scattered everywhere, sometimes collected on the uphill sides of trees. Some tops and snags remained. The stand was about 250 trees per acre, and what we saw was about 100 TPA (although the forester said it was 80).

The density wasn’t as notable as the stem size: John believes in leaving the best trees and harvesting the rest. The trees remaining in this stand were spaced at 20-25 feet and almost everything was 14-20 inches dbh.

Logging operation

John explained how the loggers contracted what he calls a “hot saw” to cut the trees. We considered using a feller-buncher on our property, but it didn’t work out. This is a large machine – either a rubber-tired or excavator-like tracked machine -- that has a grapple head and saw combined. The machine grabs a tree (sometimes 2 smaller ones) and cuts them off low. Then it can lay the trees down in any direction. Essentially it creates small decks as it moves through the woods.

A grapple skidder picked up each deck and skidded it out to the landing, “guts, feathers and all.” The limbs and tops were piled at the landing, which made for some huge burn piles. The logs were sorted into Pine, Fir and pulp.

That method reduced the forest slash enough that the owners avoided a clean-up operation afterward. There was very little damage to standing trees from skidding, and practically no damage from falling trees. The stumps were very low, too.

Saw logs around here go to Sierra Pacific in Mount Vernon, Hampton in Darrington, or Boise-Cascade in Idaho. All are long hauls that quickly eat up the revenue. Closer-in mills pay so low that foresters won’t consider using them. This project started when Fir was at $580/mbf (Darrington). Then it dropped to $480, but they switched to Idaho mill and got the higher price for the remainder of their product. John says the owners made money on the harvest, but won’t say how much.

A light thinning “from below” (taking the smallest trees) typically renders about 2 MBF/acre, John said. The 10-acre cuts produced 8-10 MBF each.

Disposing of slash

We had a debate about whether mulching or chipping was a good idea. Several people have recommended it to us – we get a lot of free advice around here, and it usually begins with “why don’t you just…” – but we’re burning our piles this winter.

Wildlife proponents want the piles left for habitat. Clean air advocates want them chipped. Wildfire experts want them burned in the middle of the next winter. There was no conclusion.

Someone said wood chips make good road surfacing: I hadn’t heard this idea before, and I had my doubts. Others concurred that it didn’t sound like a great idea, especially if the road is a fire line. Chips would carry the fire across the line. Wood debris takes decades to turn into dust. They would tend to float to the surface in wet conditions. Deep chips are hard to drive in.

There are markets for chips. Avista, an energy utility with plants on the Washington-Idaho border, buys chips and there people who will come onto your property and do the chipping and hauling. (The person didn’t say what Avista pays, but said they’re importing chips from Canada and paying the cost of $2-$4/ton to haul).


We talked about seed mixes. Native seeds are expensive. We’ve been ordering comparables from Western Seed, and found it affordable enough to compensate for the shipping (we order about 150 lbs at a time and have it shipped UPS). Everyone agreed that you have to seed disturbed areas after logging. These owners had not done it, and John relegated that responsibility to them. We saw plenty of noxious weeds on our walk through this stand, especially in the roads. Seeding an aggressive native or foraging mix helps get ahead of weeds and prevent erosion.

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