Tom's Blog

Friday, April 13, 2012

The march of the clones

For the past four years I have been participating in the rise and fall of clones at the edge of one of our bur oak savannas. We have spent a lot of time (and herbicide) eradicating a clone, only to watch it be replaced by another clone. This post will end with the 4th clone that has occupied this site. This has been an interesting experience and makes one realize how difficult restoration ecology really is.

For anyone who is following our work in detail, the site is part of Unit 23, just at the top of what we call the Hickory Ravine, and close to the East Overlook.

The site was cleared of "bad" vegetation in 1999-2000, and has been burned annually ever since. There are lots of nice bur oaks here, plus substantial prairie remnants. Just a few yards away is a spontaneous population of purple milkweed, a State-Endangered species. The area always burns well, which is significant since two of the clones we have dealt with are woody.

About five years ago, after the area had been opened up, part of it became infested with Rubus idaeus (red raspberry), which is one of the more difficult bramble species to get rid of. Red raspberry forms very dense clones, with the canes so close together that almost nothing else can grow. Although other Rubus spp., such as blackberry and black raspberry, are relatively easy to eradicate (cut and treat or basal bark does the trick), red raspberry is difficult to get rid of in that way.

I had a detailed post on this menace in 2010, which should be accessed for details. In brief, the procedure we used was to spray all resprouts that came up after a burn with Garlon 3A, canvasing the area carefully in May and early June, returning twice or (preferably) three times to get the late-growing resprouts.

We were successful with this procedure, but the next year the area was replaced with a vigorously growing clone of smooth sumac (Rhus glabra). This is a serious problem also and is only slightly easier to get rid of than red raspberry, using the basal bark technique with Garlon 4 in oil. I've got a detailed post on this also. We eradicated this in the summer of 2010.

However, it seems like restoration work is never done. Late last year the same site was infested with pale Indian plantain (Arnoglossum atriplicifolium) , another fierce clone former that can also take over a whole site, at least in Pleasant Valley Conservancy. I have got several posts on this species also.

So this spring Kathie and I have been spraying all the pale Indian plantain root suckers, both large and small (some as small as 10 mm in diameter). We are confident that we can eradicate this species here, since the same technique (repeated spraying the same summer) has worked well at other sites.

Interestingly, this site is now being taken over by another strong clone former, but one that we are happy to have. This is wood anemone (Anemone quinquefolia), an early spring bloomer that seems to be well behaved. The photo below shows a small part of the tight mat that is moving in to this site.
I hope I am not wrong about wood anemone, since I have seen reports that in some places it has formed mats of up to an acre in extant. However, we have had this species at Pleasant Valley Conservancy ever since we started restoration, and it has not gotten out of hand. We'll see.

Although those dealing with garlic mustard may not agree, clone-forming species are the greatest challenge to the restoration ecologist!


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