Pennsylvania Game News - January 2012 - 64

ERE at roughly 40 degrees north latitude we live on a border that few people note. It’s no clear boundary. It’s an ill-defined overlap, born of 10,000 years of ebb and flow. A scatter of black walnut trees stand in a glade where I often walk and sometimes hunt. In September, red squirrels scurry throughout the naked crowns, cutting the green globes free with a deft bite of stained incisors. The husked nuts hit the earth with a resonant thud. One red can drop two dozen spheres a minute, hurling cheeky insults at other squirrels that encroach too close. After a red squirrel’s cutting session it descends, sloughs off the husk and doggedly carries off nut after nut, by exactly the same route. We live on a border because, continentally speaking, black walnut is a tree of the south. It grows in loose colonies, on moist well-drained bottom lands, from Florida to the Great Lakes’ southern shores. Red squirrels, conversely, are northern rodents. They forage from Alaska, across Canada’s spruce-fir belt to the Great Lakes from the opposing direction. Only along a blurred band from Pennsylvania west to patchwork Minnesota prairie do the two species meet. Ecologists believe black walnut is exploring its way northward in the wake of the great glaciers, advancing in warm cycles, retreating in cold. It remains to this day timid of frost, shedding early and leafing out late. Walnut co-evolved in its southern hardwood stronghold, scientists say, with the gray squirrel, each shaping the other’s habits and form. But when it met the red squirrel, walnut encountered a new obstacle, perhaps as formidable as frost. Gray squirrels, as any observant hunter knows, are “scatter-hoarders.” Stashing food for winter, grays rove through the woods, burying each nut singly in a shallow bed. Walnut seeds “like it” that way. Right now, those gray squirrel treasures lie dormant beneath moldering leaves and transient snow, poised to shoulder through rock-hard shell that a squirrel’s determined gnawing can take six minutes to pierce. A red squirrel’s way of caching for lean times is different. Red squirrels are “larderhoarders.” They stash their bounty by the hundreds in piled stores — in tree hollows and boulder clefts. I have found their walnut and pine cone caches in my springhouse, under the hood of a rusted truck, inside my kayak on its rack in the yard. Larder-hoarding works well for red squirrels, hard-wired as they are for winters where snow mounts deep and long. Stockpiles, though, do not favor seed sprouting or a tree species’ spread. Red squirrel caching presents a reproductive challenge to walnut along the front lines where the two are already engaged. But response to just such tensions is how all wild things become what they are. A more recent wrinkle, though, may incite a wider conflict of higher stakes. Where man’s designs carve and shrink eastern and Midwestern woods, the opportunistic red squirrel moves in and supplants the gray. Pondering how and if walnut will cope has a familiar feel, as we learn yet again how entwined is the web of life in these woodlands of home.
64 GAME NEWS

Border War

Pennsylvania Game News - January 2012

Table of Contents for the Digital Edition of Pennsylvania Game News - January 2012