As I walk the walnuts, either measuring pole or diameter calipers in hand, as it is measuring season, there are things that I notice. It is spring here, though the trees are one of the last to emerge from their winter solitude. When I am measuring height, I often look beyond the tip of the tree to a solitary bird well up in the sky making use of the currents that there must be at that altitude. Not geese, for they announce their passing well in advance, and clear the sky by force. No, these are occasional hawks or gulls that catch my eye and make me pause and wish that I had their talents for silent passage. Where are they going, and who awaits them?
When I am measuring diameter (I measure height and diameter separately, because I struggle to carry all those bits and pieces at one time) my gaze is closer to the ground. Why, I wonder, is there an apparent association between ants and black walnut trees? In my field where I collect most of this data, there is commonly one ant hill between 50cm to 1m from the base of the tree, in the grass-free band along the rows of trees. I frequently find the ants cruising the tree, though sometimes stationary on the terminal buds, and I can only surmise that they are feeding on the sap I sometimes see escaping from larger wounds. But I am amazed that the rule is one hill per tree, where I find them (not all trees have anthills). If this were not a deliberate association, I would expect to find anthills at random distances between pairs of trees, and perhaps in multiples, but this is not the case. Who passes the message on? This is my tree, mate, go and find your own (actually ‘ours’ given that ants are social insects, but ‘ours’ doesn’t mean ‘yours too’). Perhaps there is a scent trail at the base of the tree which says just that: Trespass at your peril!
