Forest Health

From time to time, landowners of wooded lots might be thinking, for various reasons, about logging their stand of trees.

Danger signals might have just gone off in most readers’ minds when they read this opener.  Logging has such negative associations:  clearcutting that’s ravaged a landscape and left wood debris everywhere; harvesting equipment that’s compacted soils or caused erosion; habitat damage that will take decades, or longer, to recover.

But logging needn’t entail this dire scenario.  In fact, sensible logging may be necessary for many Island forests to promote ecological health. That’s because most Island forests are, to use a technical term, overstocked—too many trees per acre for the forests to do well.  Many forest stands on Vashon are also of uniform age and size—not a healthy situation either.

Much of the overstocking on Vashon takes the form of trees that have done well since the last logging event mixed in with trees that haven’t.  (Nearly all Vashon forests have been logged at least once, and most more than once.)  You may look at a wooded area and think you’re seeing older, bigger trees next to younger, smaller ones, but what you’re probably seeing are trees of the same age that have succeeded more (the bigger ones) or succeeded less (the smaller ones.).

In this case, a kind of logging often called ecological thinning, may be necessary so that the dominant and co-dominant trees (the bigger ones) can do better once the intermediate and suppressed trees (the smaller ones) are removed.  Many of the latter aren’t doing well and may never do well because of poor genetics, bad soil and light conditions, and so on.  This kind of thinning also may remove some of the big trees if they’re so thick together they stunt one another and block light from getting through their dense canopy, creating a forest desert beneath them where plants can’t grow and animals can’t thrive.  This canopy thinning may permit trees that are smaller because, in fact, they’re younger to be retained, and their “release” builds height and age variety in a stand—very desirable for forest health.

The one kind of logging you definitely never want to do is sometimes called “diameter-limit cutting” or, more crudely, a “real-estate cut.”  In this form of forest butchery, all the larger trees (i.e., the most successful ones) are logged off, leaving behind the smaller trees (i.e., the evolutionary losers), on the assumption that the smaller trees will grow up to be bigger ones if given light and space.  In almost all cases, this never happens.  The result is a forest so compromised that, unless large-scale restoration is undertaken, as much as a century will pass before forest health returns to it.

To avoid near-irreparable harm along these lines, let’s draw needed forest products from managed working forests, both on-island and off-, that utilize best practices in timber harvests. Then we can cultivate non-commercial Island forests not for wood but for the ecological services they provide, as well as the good feelings we get from a healthy forest ecosystem Island-wide.