Tuesday, December 16, 2014

The Bradford Pear in Autumn

Last spring I wrote a lengthy post in defense of the Bradford Pear tree. These ornamentals are criticized by some naturalists as nonnative and invasive. I won't revisited the arguments I made in that post except to say that I continue to find the trees interesting and worthy of further study.

Bradford Pears were once encouraged because of their lovely autumn foliage. A lengthy and hard freeze this November somewhat damaged the colors, but the fallen leaves still made a very pretty carpet.

As an aspiring naturalist, I treasure my two Bradford Pears because of their contribution to the local habitat. Of all the trees on our heavily-wooded four acres, these two are the only ones regularly drilled by Yellow-Bellied Sapsuckers. In past years we have had a wintering pair, but this year we seem reduced to a solitary male.


In addition to being a winter feeding station for Yellow-Bellied Sapsuckers, Bradford Pears are also a source of berries for Cedar Waxwings. Last weekend so many of them flocked to the trees that our Pontiac Vibe was fully coated in bird poop! Despite that, they are lovely birds--but I wish one of those with the red-banded wingtips had posed long enough for a snapshot!
Those who dislike Bradford Pear trees may be distressed to see the pictures of the Cedar Waxwings feeding on the berries. Those birds will very likely spread the seeds far and wide--perhaps to germinate and produce Callery Pear saplings . . . . I'm certain that I cannot fully allay their concern, but here is what I know: Not far from our cabin there is a large, grassy field of perhaps five open acres. It is bush-hogged occasionally, but it has not been mown in recent years. A variety of saplings are now springing up amid the grass--Redcedar, Honeylocust, Winged Elm, Gum Bumelia, and more. If Callery Pears were an invasive threat in this area, they should be springing up in that field. I have not found any. Bradford Pears are supposedly sterile, but I've never tested that. To do so this spring, I've planted ten seeds from my trees; I'll be interested to see if they germinate. Perhaps the invasive thickets that some have reported are more the result of spreading from rhizomes than from seeds.

Bradford Pear trees don't reveal all their delights until the spring when they are among the first trees to blossom. Birds, bees, moths, butterflies, spiders, caterpillars, wasps, and treefrogs benefit from them. I look forward to documenting that annual event. But just before the leaves began to change colors this fall I made one more close inspection of the underside of the leaves. Unless I am mistaken, this last photo shows the remnants of two butterfly eggs. This year I hope to identify which species of butterflies and moths use the tree as a host plant.

Update: 4/29/2016 This spring, as always, the Bradford Pears in my yard were filled with lovely blossoms. And as is usually also the case, these blossoms satiate the hunger of the early spring pollinators for nectar. On one sunny, still afternoon the sound of those happy insects was the loudest noise in nature as I stepped out my back door.

In the picture above I show a couple of caterpillar egg cases. The caterpillars that feed on these trees are the native Choristoneura rosaceana (oblique banded leaf roller), which eventually turn into an attractive (though fairly ordinary) little moths. Of course, both the caterpillars and the moths are nourishing food for many species of birds.