It seems perfectly logical. Cut the bigger trees and leave the smaller trees to grow. It makes all the sense in the world, especially when the money is made from cutting the larger trees. You make money and you’re doing well by the forest because you’re leaving trees for the future! It’s the perfect situation.
Unfortunately, that’s not the way the forest works in the real world.
The vast majority of Pennsylvania’s forests have a long history of being cut over heavily and burned from wildfires. Essentially, the forests started from scratch beginning as seedlings, and stump and root sprouts, which makes them even-aged. By definition, even-aged is where the trees are within 20 years of age from one another.
The forests began to grow again from cut over, burned and consequently open areas, which favored sun-loving, shade intolerant to only moderately shade tolerant species. In a nutshell, the tree species that comprise the great majority of Pennsylvania’s forests today do not regenerate or grow well in the shade.
The larger, more dominate trees in the woods won the race for sunlight. The majority of the trees died from the competition. A regenerating clearcut truly is the epitome of only the strong survive.
Even so you’ll see some smaller trees have managed to survive. They tend to be of low vigor, low value, perhaps crooked, damaged and maybe diseased. But remember, they are basically the same age as the healthy larger trees. They were just out competed. Perhaps it was luck of the draw, or perhaps a stump sprout had an advantage over a seedling because it already had a large root system, or maybe the loser had inferior genetics. Whatever the reason, when a tree has been suppressed for a period of time it will not respond well to the increased space and light. Its growth response will be very limited and it will not grow into a valuable timber sized tree.
By now a light bulb has probably gone off in your head. Ah ha! Just cutting the big trees leaves behind junk as the future forest stand, which won’t grow well.
What is taking place is called high-grading, which is when the high grade trees are harvested leaving the smaller, low value and low vigor (low grade) trees as the future forest.
It is not sustainable forestry. It gives no consideration for the future forest’s species composition, spacing, wood and wildlife production or new forest establishment through natural regeneration. There are other types of cuts that realize present income while providing for future sustainability, and consequently future income also.
Contributed by Christopher Jones, Service Forester with the PA DCNR Bureau of Forestry
Pennsylvania Bureau of Forestry foresters are available for assistance to private landowners free of charge. Interested landowners can call 814-472-1862814-472-1862.