Tom's Blog

Friday, September 19, 2008

Making progress on a bur oak savanna

We have been restoring Unit 10, one of the bur oak savannas, for about 9 years. It started as a fine stand of open-grown bur oaks that was completely overgrown with buckthorn and invasive trees. It had very few forbs and no grasses. The first year we tried to burn it, it did not burn at all. The second year it was slightly better. We started clearing in 2000, and began almost immediately to overseed with native species collected elsewhere on the Conservancy. Our yearly routine has been to burn, plant seed, monitor in the spring and summer, weed, remove buckthorn resprouts, and continue monitoring. We have also worked to control the extensive bramble populations that developed.

We have burned in either spring or fall, and since 2004 have had some good burns and some spotty burns. We started seeing prairie grasses about three years ago, and they have been spreading ever since. The most obvious is Indian grass, but little bluestem is also present. In the shadier areas we also have savanna grasses (silky and woodland rye, bottle brush grass, woodland brome). We also have lots of forbs, and the species count for this unit is over 100.

With the good prairie grasses now present, we are getting better burns, which help keep the brush down. This last spring we had one of the best burns we have ever had. (Cutting and herbicide treatment also play a major role in brush control.)

Among the forbs we now have good populations of cream gentian, showy goldenrod, and large-flowered false foxglove (which grows semiparasitically on oaks), among the more common species.

It obviously takes time to restore a savanna, but persistence pays off. Unit 10 has the potential of being one of our finest savanna restorations, but we must keep on top of it.


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