The Benton County Chapter has revived our popular “discussion group tours” or “twilight tours” where we visit each other’s properties and discuss forest management ideas. It’s an opportunity to see what/how others are doing things, show off our accomplishments, make suggestions, ask questions, discuss issues and problems and just have a general learning experience. No formal agenda, just sort of an in-the-woods discussion session.
On the morning of March 30th, the discussion group visited my place. We have about 285 acres on the Marys River in Wren, where we have lived for about 35 years. Our land is a mixture of conifer forest, oak woodland and prairie. We have planted thousands of western red cedar and Douglas fir over the years – that now need some serious thinning. We took a look at a few of these stands and discussed whether it was time to thin the 20-30 year old western red cedar stands, why some of our Douglas firs are dying, whether to thin an older stand of grand fir and how to approach thinning our mixed hardwood/fir stands. We came away from the discussion with some great input and ideas.
Our western red cedars display a fair bit of variability in diameter within the stand that was planted on a 10-12’ spacing, but with a number of older fir and oak trees scattered throughout, retained from a harvest about 50 years ago. We cored a couple of the trees to get a sense of whether some had slowed in their growth, but found that the annual growth was relatively consistent and did not show any recent slow-down. We discussed how cedar, with its greater shade tolerance, was able to sustain growth without thinning for longer than fir. However, it was suggested that the rate of growth might increase if we thinned. It was also suggested that unless we have a specific market or need for the cedar, we might want to leave it for now or do a test area and see if we observe any increase in growth rate.
We looked at an area where 40-50 year old Doug firs are dying, particularly along the outer edges of stands. It was theorized that because the soils are relatively wet and of higher clay content, the firs don’t extend their roots very deeply. Then, when there is even a short droughty period, the trees are more likely to experience stress.
As we were walking through the forest, one of the participants with a forest pathology background noticed a needle fungus on our Douglas firs. He identified the fungus as Rhizoctonia butinii, and the disease as web blight. The hyphal threads grow from needle to needle, on the outside of the needles, webbing them together. It is apparently native to our area, widespread but not really common. Some years it is more visible than others, but even in a bad year it doesn’t do much beyond a little growth loss. Sometimes it ruins the appearance of Christmas trees.
We rounded out the tour with a visit to an older established stand dominated by Grand fir and located on a bench high above the Marys River. The tree spacing is irregular but dense and the trees appear healthy. We discussed whether it would make sense to thin the stand. We learned something from one of the tour participants – that Grand fir have notably thin bark and that retained trees are easily damaged during a thinning operation. It was suggested that it might be best just to leave this stand alone.
Our next “twilight tour” will be hosted by Sarah and Ken Edwardsson in the evening on Friday, August 23rd (see Schedule of Upcoming Events). Sarah & Ken have been actively logging to improve their oak woodlands, so it should be another interesting event. Bring your own drinks and snacks, if you wish, and dress for the weather.
Announcements of the “twilight tours” are sent to BCSWA members via email and are posted on our Chapter page of the OSWA.org website. If you know of other landowners, family members or anyone else who would be interested, or would benefit from this event, by all means, invite them along.