June 5, 2009 at 10:54 am (botany, ecology, mammals, paleontology)
Tags: Gymnocladus dioicus, Kentuckee coffee tree, mastodon, Mayslake, seed dispersal
by Carl Strang
In one of this spring’s earlier posts I mentioned the difficulty Kentucky coffee trees have in getting dispersed, now that mastodons and other herbivorous megafauna no longer are around to facilitate their transport. Recently, though, I noticed that the grove of Kentucky coffee trees at Mayslake Forest Preserve has quite a few saplings coming up around its periphery.
Most of this photo is occupied by a single, bipinnately compound leaf extending upper left to bottom right and out of the frame. Though dispersal distance clearly is more limited than it would have been in the gut of a mastodon, these trees are reproducing just fine, thank you very much.
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April 10, 2009 at 11:18 am (botany, ecology, mammals, paleontology)
Tags: black spruce, Field Museum, Gleditsia triacanathos, Gymnocladus dioicus, honey locust, Kentucky coffee tree, Maclura pomifera, mastodon, mastodon dig, Mayslake, osage orange, Picea mariana, Pratts Wayne, Scott Demel
by Carl Strang
In an earlier post I briefly described the paleontological dig that has begun in Pratts Wayne Woods Forest Preserve, centering around the find of mastodon molars and bone fragments. I mentioned that in 2008 the major discovery was of buried trees along with some black spruce cones. The Field Museum’s Scott Demel had the wood analyzed, and it proves indeed to be close to the same age as the mastodon, around 13,500 years. (In the earlier post I said the mastodon fossils were 11,500-12,000 years old; this was actually the raw carbon-14 date range, which has to be adjusted, for instance through use of tree ring records, to give the correct number of years in the past). So the mastodon died at the edge of a spruce-fringed lake.
On a tangentially related topic, recent wind storms have blown down some of the seed pods from a grove of Kentucky coffee trees beside the entrance drive at Mayslake Forest Preserve.
These pods may have coevolved with mastodons and other extinct giant herbivores.
The Kentucky coffee tree’s big seeds are very thick-walled and hard, just what you might expect if they need to pass through the mill of an oversized herbivore’s digestive system and survive prepared to germinate.
Without such a preparation, the seedlings have a hard time breaking out, and perhaps as a consequence the Kentucky coffee tree is relatively uncommon. Certainly in DuPage County you are much more likely to find it in landscape or restoration plantings than as a wild-germinated plant.
Another tree in the legume family that has been tied to mastodons is the honey locust.
This tree, also on the Mayslake grounds, shows the intimidating defensive thorns that have inspired the connection.
Like the Kentucky coffee tree, honey locusts have large pods. Their seeds are much smaller, however, so they have less difficulty in germinating on their own, and across its range this species is more common. It also became a popular tree for domesticated landscapes, once a thornless variety had been bred.
A third species whose seeds may have been dispersed by mastodons is the osage orange. I have not found any of these at Mayslake, but several grow beside Spring Road, less than a mile to the east.
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February 21, 2009 at 12:43 pm (botany, mammals, paleontology)
Tags: black spruce, mastodon, Pratts Wayne Woods
by Carl Strang
Over the past two summers I have had the opportunity to participate in a paleontological dig at Pratts Wayne Woods Forest Preserve in northwest DuPage County. This excavation, conducted by the Forest Preserve District of DuPage County and the Field Museum of Natural History, was prompted by the discovery of three mastodon molars and some bone pieces during wetland restoration work.
Photo courtesy Forest Preserve District of DuPage County
The dig is being structured as an education opportunity for area residents. Teachers and high school students have been the core participants in the first two years. There have been tours, presentations and half-day dig opportunities for members of the general public.
During the first summer, the main products were large numbers of small tusk and bone fragments.
In 2008 the digging revealed some small buried trees.
Wood samples are being analyzed, but two black spruce cones were found among the trees.
As I mentioned in my account of last fall’s glacier retracing trip, that tree species no longer grows this far south, but was here in this mastodon’s time 11,500 or 12,000 years ago. These paleobotanical discoveries fill in some of the picture of the local environment as local climate warmed after the glacier melted away.
With the major bones still waiting to be found, there is plenty of motivation to resume the dig when circumstances permit.
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