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- Working Forests
Pundits and politicians could learn a thing or two from a New Hampshire woodlot. For all the science involved in managing the inevitable change in the composition of a forest, sometimes the change a forester wants just doesn’t happen. Sometimes an effort to get the white pines to grow where mixed hardwoods have taken over just doesn’t take.
A forest is a highly competitive environment where the various species inclined to reside there sometimes join forces in their efforts to thrive, but more usually battle each other for the resources they need. The different tree species have adapted over time to thrive under different qualities and quantities of soil, sunlight and water. And every individual tree races to outcompete its own brethren for a healthy share. To political junkies, this may sound familiar.
In New Hampshire its often said that White Pine is king of the forest products industry, where it has long been among the most valuable—and abundant—species on the market. Where it grows well—on well-drained soils with plenty of sunlight—it does so relatively quickly, rising high and reaching above other species. It’s a good-looking tree that provides jobs for foresters, loggers, millworkers and people who build things.
The White Pine is also shallow-rooted, however, and is thus susceptible to wind events. A big hurricane can make match sticks out of a stand of white pine in an instant. The politically-minded among us may be familiar with this concept.
In a mature forest, life-giving sunlight is at a premium below the canopy. Thus in our forests we will find shade-tolerant species such as sugar maple or hemlock that can slowly grow despite a dominant overstory. They live in the shadows, if you will. If you want to predict the future composition of a given forest, it helps to turn your eyes from the overstory and look closer to the ground, in the shadows, to and look for the next generation sprouting up. Politicos sometimes forget this and end up predicting the past instead of the future.
There are also those species who love to jump in when there is no canopy. When, as a result of a fire or a storm or a harvest, or maybe an agricultural field is allowed to become reforested, you’ll find fast-growing early-successional species like birch racing each other to the sun. They are known as pioneers and produce great quantities of wind-blown seeds, enabling them to take large gaps in the forest quickly. You might hear this growth referred to as "popple".
Foresters use their knowledge of how these different species grow under different conditions to manage a given woodlot. If an ideal site for White Pine has been taken over by hardwoods, for example, a forester might plan a harvest that is timed and selectively cut to increase the chances that White Pine will regenerate and outcompete the hardwood.
But it doesn’t always work out that way. You might do everything the latest science suggests you should do in order to change the composition of the forest—scarify the soil, get sunlight to the forest floor, leave seed trees—and it just doesn’t take. Sometimes the trees themselves end up determining what the forest will be. Sometimes those running for public office or predicting the outcome of an election learn that the hard way, and get taken to the woodshed.
Jack Savage is the editor of Forest Notes, the quarterly magazine of the Society for the Protection of New Hampshire Forests. Forest Notes is celebrating its 75th anniversary of continuous publication this fall. Savage can be reached at jsavage@forestsociety.org.