Tuesday, August 5, 2014

Waiting for Fruit

On my neighborhood walks I find myself looking down at strategic moments for fallen fruit.  Tracking the seasonal changes in different trees (aka phenology), involves noting the dates of first leafing out, flowering, fruiting, and maturing and falling of fruits and seeds, then coloring of leaves, and finally leaf fall.  When I can, I check on fruit by looking at the trees themselves, but sometimes this doesn't work.  Some of the trees are simply too tall, with too few lower branches to see clearly.  In some cases, trees bear no fruit, which can lead to some frustration while staring aloft with binoculars.  The lack of flowers or fruit in the youngish pignut hickory in the woods would have kept me guessing for a long time, if not for the flowering and fruiting of a larger neighbor with low branches. 

I was embarrassed to miss a lot of these changes in the big white ash in my yard: it leafed out late in the spring, and I waited a long time for it to show flowers, but saw none.  Only later looking on line did I discover that white ash leafs out and flowers simultaneously--the flowers are small, and the tree very tall with no low branches.  Since all I can see from the ground is leaves, I can only assume it flowered and the fruit is maturing; I will watch for the slender, one-winged fruit on the ground in fall.  

 Crown of sixty-odd-foot white ash catches the sun's last rays.  Other photos are close-ups of the crown, most taken on a tripod, at zoom of 3.6X, and uploaded at full resolution.  Can you find any of the fruits?

I've even attempted to get a look at the ash by telescope: here I'm shooting through
the eyepiece of a four-inch reflecting telescope.  Still nothing.

Several kinds of oaks do this to me routinely.  Female oak flowers are in small and and inconspicuous clusters, but fortunately the male are in drooping catkins that are more visible.  On the other hand, an acorn an inch or less across is hard to spot in a fifty-foot tree.  There are enough scarlet oaks that some have low enough branches for me to watch, but red oaks are much scarcer, and I know of only one indisputable black oak on my neighborhood ramblings.  Both white oaks in my back yard are tall: more staring at the ground.

Red oaks I watch.  The last, on the mound, is actually a cluster of several separate trees;
two of these have small branches at eye level, but these branches did not bear flowers.

The only black oak I've seen in the neighborhood has some low branches, but I would have to 
trespass to get a really good look.  One day soon I'll talk to the landowner.

I was delighted to discover, early in the summer after high winds, a fallen twig that proved that a sugar maple I watch was female; I had concluded that all the sugar maples in my neighborhood were male, since I'd seen no keys (double-winged fruits).  Their invisibly sparse fruiting contrasts with the prolific Norway maples, which often bear so heavily that the tree changes color as the keys mature.  So far, the only way I know there are probably still keys up there somewhere is finding one fallen on the ground, the embryos killed by insects.  Confusing things further, it seems that sugar maples are sometimes bisexual.  So there may be more "females" yet, though with few enough keys that they have not yet declared themselves to me.

Fallen sugar maple twig.  The keys have an almost square shape,
unlike the nearly straight keys of Norway maples, or the V-shaped keys of red maples.

Aha! must still be some up there somewhere.

Most of the fallen keys I've encountered lately have had both embryos eaten by insects, 
but this one seems to have one seed intact.  I wonder if it would grow?

For all these reasons, I spend as much or more time looking at the ground under such trees as looking at the trees themselves.

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