The hands of men and women wielding chain saws and steering skidders are forces of nature. Just as much as ice storms or insect outbreaks, tree harvesting practices have sculpted the biomass that is our present-day forests.
Most of us know the story: seventy-five percent forested now, Vermont was once seventy-five percent open. First it was subsistence farmers, then the wool industry that took down the trees. By the end of the nineteenth century, the expansion of logging railroads and the development of the pulp paper industry spelled the end of much of what was left. Then the trees came back. But the forests that returned probably didn't look much like those they replaced.
Our forests have been cut once or twice since, and by now look even less like their ancestors. This time it's not necessarily because men and women wielding saws and skidders cut them. It's more how they cut them.
In the early twentieth century, when large-scale clearcutting began to lose favor with forest producers in this part of the world, two harvesting methods were widely recommended instead. Diameter limit cutting and high-grading techniques are still common in timber operations throughout the Northeast.
Decades of research have confirmed these methods result in degraded forest stands. Ralph Nyland, SUNY College of Environmental Science and Forestry Distinguished Professor of Silviculture, has led this research effort, and will share his findings at an upcoming workshop sponsored by the Bennington County Sustainable Forest Consortium.
Bottom line, these exploitive harvest practices can't see the forest for the trees - the trees that are worth the most money at the time of harvest. Diameter limit cutting removes all merchantable timber above a certain diameter at breast height. High-grading (or "cutting the best and leaving the rest") is a kind of diameter limit cutting, since trees must be a certain minimum diameter to be merchantable. In both cases, the harvest focuses on what is removed from the forest. What's left behind might as well not matter. But if you're a forest landowner, it matters a lot.
And what's usually left behind are poor-quality trees or a high proportion of species for which there is no market. So while the first harvest might be remunerative, the next will be much less so - and so on, on down the years.
In fact, in terms of the return on the landowner's investment, Dr. Nyland's research shows that forests subjected to diameter limit cutting support less frequent harvests, and produce less volume, less value, and less consistency of yield as compared to more appropriately managed forest stands.
This is an important statement in the forestry world - that appropriate management over the long term results in the greatest financial return for the long-term forest landowner. In sponsoring Dr. Nyland's visit, the Sustainable Forest Consortium hopes to both help forest owners maximize their long term return and sustain the health and potential of our region's forests.
Just what is appropriate management will depend on factors like forest type, age, and landowner desires. Each forest will need its own prescription, but it will probably combine some basic ingredients, among them: When harvesting larger, canopy-reaching specimens, leave a few to serve as sources of seed. Thin the forest stand occasionally to improve tree spacing and access to sunlight. From time to time, create small patch cuts where regeneration of sun-loving species can take place.
And that's just a short list. If you're a forest owner, ask your forester to tell you more - about sustainable, not exploitive, forestry.
Shelly Stiles is the district manager of the Bennington County Conservation District, whose mission is promoting rural livelihoods and protecting natural resources in southwestern Vermont. The Bennington County Sustainable Forest Consortium is a collaborative between forest landowners, consulting foresters, loggers, the Bennington County Conservation District, and the Bennington County Forester's office. Its mission is to promote dialogue and learning between forest landowners, resource professionals, and the general public.
This column appeared in the Bennington Banner in August 2008, as one of the BCCD's Conservation Currents pieces, a bi-weekly feature written by BCCD board and staff members since August 2006.