Forest Maintenance - Continuous Quality Improvement

July 19, 2015  •  1 Comment

Initially I thought it would be fine to allow nature to take its course in the forest.  That there would be little intervention required of me, just sit back and watch the lions stalk the antelope and let nature take its course.  I would be free of lawn mowing, weeding garden beds and other things associated with suburban yard maintenance.  Deer and elk would keep plants trimmed and I would not have to ever weed again.  

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In going through the acquisition process for this land I learned it was "Designated Forest Land" and there are significant tax incentives to maintain this status.  This required having a forest management plan in place for the property.  There was a written management plan the previous owners had prepared in the mid 1990's involving thinning the forest through selective logging to maintain the health of the remaining trees.  I hired a consultant to provide an updated plan to transfer and maintain the status of "Designated Forest Land."  In this survey I learned a few things about this parcel of land that at first looked like nothing more than a fine forest to my untrained eye.  The consultant, in looking at the previous plan from last century, noted that the owner was diligent in following the recommendations and as a result the forest was generally in good shape.  Nonetheless, there would be a lot of work required to continue to maintain and improve the land.  There were still quite a few trees that need removal to allow the most vigorous trees to grow and minimize the risk of diseases that can destroy densely packed stands of trees.  This will also lessen the amount of fire fuel available.  I also learned that most of the road sides (7/10 of a mile of road) were heavily infested with noxious weeds:  diffused knapweed and spotted knapweed.  Knapweed is native to Central Europe and has been rapidly infesting North America for over a century.  One article I read stated the increase of knapweed was 10 percent annually.  Why is knapweed so bad?  Well, it will quickly establish itself in areas of soil disturbance and crowd out native plant species destroying plant diversity and contributes to erosion and silt in waterways.  By August knapweed can be up to 4 feet in height, is dried out and a fire hazard.  Knapweed is able to outcompete native plants because it is a prolific seed producer; thousands of seeds per plant, and these seeds remain viable for up to eight years.  And now for the creepy part... knapweed secretes a growth inhibitor that prevents other plants from growing around it.  There are some sources that caution people to wear gloves while pulling it because it the sap could contain carcinogens.  I have yet to find a source that will definitively confirms this, however.  I wear gloves and wash my hands after dealing with it though.  I did a bit of research and found that there are biocontrol agents available.  These are in the form of a weevil - Larinus minutus - that specifically targets knapweed and has no history of harming other plant species.  The weevil eats the knapweed and lays its eggs in the seed heads.  The emerging larvae then eat the seeds before they can be dispersed.  They over winter and are ready to get back to work the next summer.  I contacted the Washington State University Extension's Integrated Weed Control Project and spoke with Dale Whaley, the Agronomist for Chelan County, and arranged for a bio-control release this summer.  Dale met me at the property in mid June and confirmed that the infestation of knapweed was significant.  He doubted that the bio-control agents would be able to conquer the knapweed by themselves.   untitled shoot-2873untitled shoot-2873

Dale suggested that I also spray the knapweed with a specific selective (and expensive) herbicide that will not affect native grass.  After some limited success with the spraying (thinking at the time it was the lesser of two evils) I resolved to finish the rest of the herbicide early in the growing season next year and be done with that strategy.  I have suspended the use of the herbicide this year since most of the plants have gone to seed already.  With the very limited effect that the herbicide had on the knapweed population as a whole I can not justify in my mind continuing to put more poison into the forest year after infinite year.  I will have to resort to mechanical control - pulling the weeds and cutting them before they go to seed; cultural control -continuing to plant competing grass and other native plants; and the above mentioned bio-control.  I also have to be at peace with the realization that I will only be able to control, but not entirely eliminate, knapweed since it is infesting neighboring parcels of land and is dispersed by wind and browsing deer.  A lot of knapweed is found along mule deer migration trails, and mule deer can migrate up to 70 miles.

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We must think about the long term effects of what we do in the environment. 

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Ron Large(non-registered)
This is a very interesting blog Bob. Thanks for sharing. Sounds like you have your work cut out for you for a few years get this under control. I am sure you will learn a lot more about your forest over the years, but that is part of the enchantment of living on the land. I love the pictures of the animals and birds your land supports.
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