Thursday, October 29, 2009

Oak Island

Blue Jay Barrens doesn’t have enough water to make an island in the traditional sense. The islands I have here are ecosystems or patches of vegetation effectively isolated within the landscape. My oak island is a patch barely 40 feet across that contains an incredible diversity of oak species. The island is surrounded by prairie on one side and Eastern Red Cedars on the other. There’s even an eroded bank that acts as the shore of the island.

One thing that makes this island particularly significant is the presence of the only specimen of Post Oak, Quercus stellata, that I have found at Blue Jay Barrens. Post Oak is one of Ohio’s uncommon species and it would really be nice to have more than the one tree.

The Post Oak I do have isn’t even a prime specimen. The bulk of the tree is a horizontal branch that grows out over the eroded bank. The tree appears to be healthy, but horizontal growth like this is usually destined to failure. I’ve searched this tree every year for acorns and have yet to find the first one.

Growing beside the Post Oak is a Blackjack Oak, Quercus marilandica, another uncommon species. There is a general similarity in leaf shape here. If you look closely, you’ll see that the main veins of the leaf end at a bristle tip extending from the leaf margin. This puts the Blackjack Oak in the red oak group instead of the white oak group with the Post Oak. Oak leaves can be highly variable in shape, even when they occur on the same tree. This leaf is not the typical shape for a Blackjack Oak and more resembles the leaf of Bush’s Oak, which is a hybrid between the Blackjack Oak and a Black Oak. Checking twig, bud and bark characteristics suggest to me that this is in fact a Blackjack Oak. Of course, I’m often high susceptible to the powers of suggestion. Especially when I’m the one making the suggestion. These oaks deserve a more detailed study.

Several other oaks have inserted themselves into the mix. Here is White Oak, Quercus alba.

Shingle Oak, Quercus imbricaria, is common at Blue Jay Barrens.

Another common species is Chinquapin Oak, Quercus muehlenbergia.

These oaks are growing in a tangled mess with some large cedars. I’d love to remove the cedars and allow the oaks to grow without competition, but cedar removal would create several problems. The oaks are growing through the cedar branches, so there is no way to remove the cedars without damaging the oaks. If the cedars could be safely removed, the oaks would probably not stand on their own. Oaks often become dependent on surrounding trees for support. When that support is removed, the oaks bow over and side branches begin to compete to be the new leader. The result is a misshapen tree with little chance of long term survival. The management decision here is to leave the island alone.


  1. HI there! Thanks for joining my blog! I think its great that you have such an interest in trees - we live on about 3 acres of woods - lots of oak, pine, maple, birch, cedar, juniper, butternut (not so many), poplar, sumac - But I'm going to take a much closer look now and see what exactly we do have! I never knew there were so many oak species -

  2. We've got quite a few oaks on our property, too, but I haven't taken the time to try ID-ing them. I think next year I might like to work on cataloging our trees. ID-ing the maples and oaks will be tricky, though.