As I use the term clearcut, it is a Regeneration Method designed to restore the area to forest as quickly as possible.
Deforestation is a change from forest to non-forest caused by cutting all the trees. It's difficult for a layman to understand the difference between the clearcut method and deforestation, but they are in no way equivalent. The only similarity lies in that trees are cut.
It's unfortunate that the popular terminology is so amenable to controversy. I used and prefer the professional phrase: "I prescribe regeneration harvest with the clearcut method." Then if the prescription were for deforestation (for a housing development for example) I would say "I prescribe deforestation harvest with the clearcut method."
Forestry was originated in Germany and has been practiced in this country only for a little over a hundred years. Most of the terminology was created before public involvement became common, so the result is public confusion.
As a matter of fact, in a strictly objective evaluation of the amount of growth that goes on in a forest, a new managed forest can achieve a growth rate that is four to five times as great as that produced in the forest it replaced. With superior seedlings and density management, the growth increase can be even greater.
What follows may be overly technical. Foresters usually don't encounter it until say their junior year.
Foresters measure forest growth in two ways: 1) Mean Annual Growth, or MAI, and 2) Periodic Annual Growth or PAI. Mean annual growth is the amount of wood on an acre divided by the age of the trees. Periodic Annual Growth is the amount of wood grown by the trees in the last period (usually ten years) divided by the length of the period (10, in the usual case). Mean Annual Growth follows a smooth curve that increases for quite some time, then levels off or culminates, and then starts declining. An MAI growth curve would look like the profile of a pimple, for lack of a better comparison. The PAI growth curve starts off by comparison like a jackrabbit, and climbs steeply for decades. The second ten years produces more than the first, the third more than the second, and so forth. A PAI curve is very steep and soars way above the MAI curve. Then all of a sudden the PAI curve plummets precipitously, and crosses the MAI curve precisely at its culmination, called "The Culmination of Mean Annual Increment."
In terms of growth per acre per year, MAI is all down hill from then on. PAI drops below MAI, and can go negative because trees die, lose volume to disease, and so forth.
A forester with a maximum growth objective chooses to harvest at Culmination of MAI in order to get the most yield in perpetuity.
Old growth forests have long since passed culmination of MAI, so even if they are not in senescence (the forest version of Alzheimers), they produce less and less per acre per year. Total volume still goes up until disease and mortality take over, but average annual growth, MAI, goes way down. Old growth forests are, well, OLD. They typically have a lot of volume. Even the finest old growth forest will eventually be replaced by a new forest -- by fire, by harvest, or some other combination of factors.
The problem with all this is that a forester typically lives about 80 to 100 years, of which he spends at the most only 20 or 30 in active practice. Forests take a very long time to grow, so even with the most aggressive industrial management, a forester would live to see only one stand that he started be harvested again. On public forests, it would take at least five generations of foresters to get a new stand ready for harvest -- about 100 years. Considering that forestry is only a little over 100 years old in this country, that is a very long time indeed.
I've prescribed treatment details for 250 years of some new stands I started after clearcut harvest. If all of my successors practice in the field as long as I did, about 25 years (the rest of my career I spent driving a desk), this means that ten forestry careers later, the stand will be ready for harvest again. I spent more time in the field prescribing than most foresters, so we would need twenty or thirty generations of foresters with a typical career to complete the plans that I made for those little trees.
Everything I've said up to now refers to one single stand of trees. A national forest or other large management unit is composed of many such stands, all with different ages, species composition, soil, water, and so forth. A forester designs a regime that allows a predictable flow of wood from all of those stands, usually in perpetuity. Non-declining Even Flow harvest is the usual public objective. It means about the same amount of harvest every year or period forever. The calculations for such a plan are exceedingly complex. They usually take hundreds of runs of some of the most complex linear programming algorithms in existence. Factor in other objectives like wildlife management, and you get even more complicated.
The usual planning period is about ten years, because economic factors beyond that are more unpredictable than the growth of the forest trees. It is a fact that some ten year plans have taken fifteen years to complete. I won't go into that one, but to me it is a direct outgrowth of the unintended consequences of well-meaning people who don't understand what they are talking about.
Forestry takes a good deal of faith and courage. It is quite challenging enough to make the right plans cloistered up like the pioneering German foresters were. The way we do it here these days, it's a frustrating and thankless job that can be performed only from inner wells of personal conviction and courage.
Fortunately, there is a fine whiskey called "Old Forester." Old foresters like me are quite fond of it.
Not really. I rarely drink, but Old Forester is the best. |
