Friday, January 23, 2015

Osage-orange

This is the fallen fruit of the Osage-orange, a tree commonly found in old fence rows.  When I see this fruit, I always think of Mammoths and Ground Sloths, two members of the megafauna that used to roam this area until their extinction nearly 10,000 years ago.  These large herbivores were the last species to utilize the fruit as a food source and were the primary dispersal mechanism for the seeds.

Osage-orange produces an abundance of seed inside the fleshy fruits.  The large herbivores would eat these fruits whole and pass most of the seeds undamaged through their digestive systems.  The animals would then wander around dropping the seeds with their dung.  In this way, the trees were spread across the landscape.

A few modern mammals are attracted by Osage-orange fruits, but it’s not really the fruit they are after.  Most of these animals, such as squirrels, are seed predators that actually open and eat the seeds.  Empty seed coats are all that remain of seeds that will have no chance of being dispersed.

The actual flesh of the fruit is left behind to decompose.

At the time of European colonization, Osage-orange was only found in the Red River Watershed region of eastern Texas.  The trees found here today were introduced and are not considered native to this area.  Since the tree was spread so easily by large prehistoric herbivores, I wonder if Osage-orange might have had a much broader range during the Pleistocene when the megafauna were so common and widespread.  I haven’t read anything that suggests such an idea, but I think it’s a possibility.  Osage-orange may have actually grown on this spot in the far distant past.

Osage-orange was commonly planted as a living fence.  Its tight growth, along with the presence of some strong thorns, helped to keep livestock contained within the field.

Their habit of spreading limbs far out into the field, caused Osage-orange to be removed by many farmers who didn’t want to be raked from their tractor seat by the thorny branches.  There are only a few of these trees growing at Blue Jay Barrens.  Most show signs of having been cut at some time in the past, most likely for use as fence posts.  Despite the fact that the seeds are viable and easily germinated, the trees are not spreading into the fields, so they don’t currently fall into the invasive category.  For now, I’ll leave the trees alone and keep imagining that a herd of Mammoths has gathered around the tree to eat fruit.

6 comments:

  1. Mastodons ate osage orange. Mammoths probably did not eat osage orange. Mastodons were browsers that fed upon leaves, twigs, aquatic plants, and fruit. Mammoths were primarily grazers that mostly ate grass.

    Osage orange has been found in mastodon coprolites excavated from the Aucilla River in north Florida. This is evidence that osage orange did have a more extensive range during the Pleistocene.

    You can read about the contents of this mastodon dung in a book entitled The First Floridians and the Last Mastodons. It's an expensive book but google books and amazon will let you read the chapter about mastodon coprolites for free.

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  2. Thanks, Mark. I'll check out that reference. I guess now I'll just imagine the mammoths standing back and watching the mastodons eating Osage-orange fruit.

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  3. Quite unusual in Ontario, but I do remember one row of them outside Woodstock where I grew up.

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  4. Hi, Furry Gnome. Osage-orange is less hardy in colder climates, but there always seem to be a few that survive in the most unexpected places.

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  5. I've always heard these called bois d'arc (naturalized pronunciation "boe-dark") or horseapple trees; that is, I'm familiar with the name "Osage-orange," but only from written descriptions or in the classroom. The French name means "wood of the bow," and supposedly refers to the Native American preference for this tree in making bows. My understanding of the practice in the South (Texas and Mississippi are my frames of reference) is that instead of trees being planted for use as living fences, the posts are usually set while still green owing to the extreme hardness of the wood once seasoned. All my life, parents, grandparents, and assorted oldtimers have pointed out trees along fences that sprouted from bois d'arc posts.

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  6. Hi, Victorian Barbarian. This tree seems to be called by many names across the country. It was also readily used in this area as fence posts. The practice of using them as living fence was common in the time before fence wire became commonly available. Most of the living fences were eventually removed and replaced with wire fence, which was more dependable and easier to manage.

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