As we gird ourselves for the loss of our ash trees over the next 15 or 20 years, we look to another tree gaining momentum in its march northward. Quercus rubrum, Northern Red Oak, is on the move. I happen to be very aware of this phenomenon because both our home in Peacham and our woodlot in Guildhall are in the transition zone.
Trees don’t actually march, of course. They shed seeds and rely on various vectors to move and plant those seeds. Maple seeds are whirligigs that get caught on a breeze, landing a short distance from the tree, or get caught in a gale, swept higher into the air, and landing who knows where. Oak seeds are acorns and acorns don’t dance on a breeze; they thud to the ground. So how do they march northward? Around here the two major vectors of acorns are squirrels and blue jays. Both creatures have a habit of gathering and caching food for later use, and both commonly cache more than they eat, leaving the leftovers to germinate and grow new oak trees.
When I first walked our land about 40 years ago, I found exactly one red oak tree. It was 11 inches in diameter (yes, I measured it). I measured it again the other day and was shocked to see that it is now 30 inches in diameter. It grows at an angle, tilted away from the stone wall that lies about 20 feet away, and the big maples that line the wall. Those maples would have shaded the young oak as it grew on the edge of a neglected pasture. Oaks are rapid growers, and 70 years ago this seedling undoubtedly shot up and angled out, away from the maple branches above, to grab some sunlight. It is by far the biggest tree in its vicinity so it was surely a pioneer when the pasture was abandoned by the farmer. The acorn that gave rise to this tree could have been planted by a squirrel or a blue jay, or some other caching creature. Any of them would have found the stone wall and its maples hospitable.
The next question is where the acorn that birthed our lone oak tree came from. I know those woods intimately, and there was no other oak tree anywhere near it. The tree sits on a slightly northern aspect, but about a quarter-mile away the land spills to the south down a steep hill. Midway down the hill lies Somers Road. This is a road that had to originate as a cow path winding its way along the hillside connecting one pasture with another. And lo and behold, Somers Road is lined with enormous red oak trees. Those mother trees are a bit over a half-mile from my young tree. That’s a formidable stretch for a squirrel but a quick flap for a blue jay.
Left to themselves, red oaks typically live 200 years and can live up to 400, so it is very plausible that the mother trees along Somers Road have been shedding acorns for 100 years or more. There is an open field downhill and the woods below are lined with younger oaks and some big ones. It’s a short flight down to the Stevens River where oak is common and just a few more miles downstream to the Connecticut valley where red oak is the dominant hardwood.
Uphill from Somers Road, the woods have only a smattering of older oak trees. Looking back 70 years, this upper hillside was sugar woods and then open pasture above. In either land use, oak seedlings would not have been welcome. Farmers in those days would have been meticulous in fixing fences and no doubt fended off any threatening oak seedlings. But as he got older and sold some land, the pasture was abandoned and tree pioneers quickly moved in. The woods that I manage there now are about 60 years old. As I have watched that steep south hillside over the last 30 years, oak has become a dominant species of the younger cohort of trees. I’d say about half of the hardwood regeneration now on that steep south slope is red oak. A few bigger oak trees are presumably supplying the acorns. Over the hill on the north slope where my original oak grows, the species is still sparse, but young oak trees are common. Go another half mile north and you’d be hard-pressed to find one today, but I see no reason why the march won’t continue. My grandchildren will know red oak as a common tree in these woods, and all over southern Caledonia County and beyond.
What I am witnessing is both forest succession and the transition of natural communities. Because virtually all the land around us was actively farmed until 60 to 100 years ago, the forest that has reclaimed the land is progressing toward maturity. The white pines that first colonized the pastures are now great big multi-stemmed behemoths. Many are losing those big branching stems to wind and snow, and some now stand dead, young maples threading their way up through the branches. The early pin cherries are gone, and the black cherry, white birch, and balsam fir are in senescence and will be all but gone in 20 more years.
Without the onset of red oak, this forest would mature into a natural community known as Northern Hardwoods, dominated by sugar maple, beech, white ash, and yellow birch. Natural communities in Vermont have been beautifully described by Liz Thompson and Eric Sorenson in their book “Wetland, Woodland, Wildland”. They have given names to about 90 different communities and their descriptions give us great clues to predicting what community we should be seeing in a given situation.
On our south hillside, we are watching the transition from Northern Hardwood to a Mesic Red Oak-Northern Hardwood Forest type. The death of the ash component of today’s forest will hasten the transition. All those dying ash trees will first be heaven for woodpeckers filling up on Emerald Ash Borer larvae, then for squirrels moving into the woodpecker holes, caching acorns. All the while blue jays will find the stark branches good places to stop on their travels, hopping down to the ground to cache an acorn or two. Sunlight will be abundant for the oak seedlings and they will grow accordingly.
Nothing in nature is static so learn how to identify a young oak and then open your eyes as you walk in the woods and see how many little red oaks you can find.
Tim McKay is a retired natural resource conservationist and current woodworker and tree farmer who lives in Peacham.