Life Webs


Regenerating trees

trees in snowOn these cold, snowy, icy days, there isn’t much to do in the way of gardening, so I have been thinking about the woods. We have about five wooded acres here, but they aren’t as healthy as they might be.

A couple of years ago, a forester from the Department of Environmental Conservation came out and cast a professional eye on the woods. “You’re not getting enough regen,” he said, which is forester-speak for regeneration. “Too much deer pressure.” In other words, whenever a tree seedling pokes its head above ground, a deer munches it.

Let’s get rid of all the deer! we thought. We hate them anyway – they spread Lyme and other nasty diseases. But the only way to do that is to fence in our whole property, about twelve acres in all, which would be wildly expensive. And, as it turns out, having too few deer is as bad as having too many. Deer are a major transportation mechanism for seeds, good seeds as well as bad ones. Without deer, you lose a lot of biodiversity.

Is there any way to have just the right number of deer? Not without more predators, and that’s a problem too. People around here tend to shoot coyote, bears and whatever else might eat fawns, because they don’t want competition for hunting. But DEC doesn’t give out enough hunting licenses for humans alone to keep the deer population in check. Even their deer management assistance program, which is not available for small properties like ours anyway, wouldn’t begin to make a dent in the population.

So what’s to be done? The only option seems to be strategic deer management – that is, protecting the seedlings we want to keep until they are large enough to withstand the onslaught of the deer. There are several methods, including tree tubes, DIY cardboard caps, and small fences, which vary in difficulty, cost and effectiveness. We’re already using small fences for the fruit trees we’re planting at the edges of the woods. (You can see an apple tree enclosed in a small fence at the bottom of the photo.) There are also techniques, such as hinge cutting, for distracting the deer with saplings you don’t want to keep.

Which trees to protect?

Now the question is: which seedlings should we protect? The canopy trees we have, in order of prevalence (more or less) are Eastern hemlock, oak (several species), beech, birch, maple, hickory, ash, and a few specimens of white pine, sycamore, basswood, and possibly black walnut down by the creek. The trees regenerating most successfully seem to be beech and birch.

Here are the tentative guidelines I’ve come up with – and I would appreciate any comments on these:

1) Don’t protect species that are subject to heavy insect and disease pressure. That includes hemlock (woolly adelgid), beech (beech bark disease, which has been endemic here for half a century), and ash (emerald ash borer arrived about a decade ago). Saplings of these species are unlikely to become mature, healthy adults.

2) Don’t protect species that can’t regenerate in shade, unless the seedling is at the edge of the woods. That includes white pine, oak and hickory, which are early to mid-succession trees. An oak forest is sustainable only by means of continual logging or fire, neither of which are we going to do on any significant scale.

3) Don’t protect species that are doing all right without protection. That includes birch and sycamore, neither of which the deer seem to prefer. (And beech, of course, but we already ruled that out for reasons of disease.)

That essentially leaves sugar maple, not coincidentally the official state tree of New York. We have a few mature trees, so we should be able to find some seedlings to protect. There are problems with gypsy moths, but they don’t seem to endanger the whole population. Sugar maple regenerates exceptionally well in its own shade, as long as the deer aren’t eating it. On top of that, it is a beautiful tree that produces a valuable product.

If spring ever comes, I’m ready to start my maple rescue mission. Watch out, deer!