Describing Sustainable Timber Harvesting: What Do Words Mean?
Posted: June 15, 2016
If you own more than 20 acres of woodlands, you have likely received a letter or postcard soliciting an opportunity to talk about harvesting trees. The letter might refer to a “select” or “selective” harvest, or cutting only trees larger than a certain diameter. Somehow, they all sound good. These words seem to say the buyer will be careful and select the correct trees to harvest, right?
From a sustainability perspective, there are right ways and wrong ways to cut trees. A well-planned and executed timber sale focuses on two outcomes: What are you leaving to manage in the future (the residual)? Or, what will or have you done to establish or release regeneration (the next forest)?
Unfortunately, terms like “select” and “selective” focus on the trees to cut, rather than the trees to keep. The buyer will select the trees to cut using some criteria such as tree diameter. Where these are the criteria, the select cut becomes a diameter limit harvest and all trees above a set diameter are sold and cut. The logic is that big diameter trees are old and smaller diameter trees are younger. This logic of big and old vs. small and young, however, is most often far from true.
Sometimes the big trees are more likely of one or several species that from the start took advantage of light, moisture, nutrients, and space and jumped ahead. These trees were successful in getting their crowns into the developing canopy to snatch resources away from their neighbors. In essence, they were the winners in the race to gain the dominant position and have continued to exploit it. When you look at a maturing woodland, you will often see that some tree species are consistently larger in diameter. Even if you see a tree species with sizes across the spectrum, just cutting the big ones is almost always the wrong approach. Cutting them first is akin to “selecting” the best and leaving the poorer.
Why does this practice of taking the best and leaving the rest occur? When shopping for fruit, if you take the best looking, someone gets stuck with the rotten, misshapen apples, peaches, bananas. Who? Of course, it is the grower or the store owner. When selling timber, if the timber buyer, or sometimes the seller, picks the best and leaves the rest, who holds the poor quality trees? Obviously, it is the landowner, and those actions and outcomes may extend well into the future as that owner or a future owner tries to recover from a poorly conceived harvesting decision.
Why would woodland owners degrade their forest? There might be reasons. Maybe there is no choice – there is a compelling need for money and taking the best is the only choice. Sometimes, though, the logic of selecting the biggest and best is perceived to make sense. That logic connects to the past and extends into the future. “My grandfather cut these woods. He only took oak trees eighteen-inches and up, and look at it now. There are lots of oaks and red maples.” Those red maples or black birches were much less common when that earlier cut was made. Lack of seed source, herbivory pressure, and other competitive plants have changed the potential for species to succeed in many places. Sometimes woodlots can sustain one diameter or select cut, but the careful observer might note a subtle shift in species composition. The second select cut will shift species, and likely quality, even further from good to worse. That is the connection to the future. How many times can we select the best and leave the rest?
Good harvesting plans have their basis in science, research, and good observation. A good harvest plan concentrates on improving the quality of the woodlands and providing sustainable options for the future growth and management of the woods. Clearly, to practice sustainable forest management takes time – it is a lot more than picking the best or biggest trees to cut and hoping that those left will grow big and strong and represent the diversity of species that can and should grow in our forests. A well-planned harvest focuses on “selecting” the best to leave. Doing this ensures quality in the next harvest, retains species diversity, keeps good genetic and species diversity for regeneration, and results in a healthier and more resilient woodlot.
It is becoming increasingly obvious to foresters, researchers, and woodland owners that regenerating healthy and diverse forests is extremely difficult. Too often, decisions to harvest fail to consider whether tree regeneration is already in place and adequate. Every timber harvest should look beyond just the trees that are cut to assess regeneration and what will benefit from the new light resources reaching the forest floor. It is great when young seedlings are already there; it is bad when the cover near the forest floor is exotic invasive plants (think Japanese stiltgrass, bush honeysuckle, garlic mustard and a host of other species) or native invasive species such as hayscented fern, mountain laurel, beech brush, striped maple and many more. Recent research data from the US Forest Service inventory of Pennsylvania’s forests find that about half of our forests, having undergone sufficient canopy removal to start to regenerate the area, have enough seedlings of desirable species to replace the forest. Our mantra, therefore, should be “every harvest has to consider the future forest.”
It is easy to fall into the trap that all we have to do is harvest the big trees and believe that the next forest will be healthy, robust, and there for the next generation of owners. Practices that on the surface sound good – select, selective, or harvests based on diameter – are not the tools we need to use to care for the land. Good forest stewardship and sustaining forest values means that we have to look forward to leave the best and take the rest.
To learn more about how to avoid mistakes when planning to harvest timber, contact the Natural Resources Extension Office to request copies of Forest Stewardship Number 7: Timber Harvesting an Essential Tool and Regenerating Hardwood Forests: Managing Competing Plants, Deer, and Light.