Tom's Blog

Friday, October 5, 2012

New Jersey tea: interesting fall regrowth phenomenon

Before this latest episode of cold weather, a number of prairie and savanna species had undergone new growth spurts. This new growth occurred after seed formation was finished and presumably gave these species a head start for next year. See my 2008 post for more detail on fall regrowth in some prairie and woodland species.

We have quite a bit of New Jersey tea (Ceanothus americanus) at Pleasant Valley Conservancy, almost all of which is native to the site. This is a fairly conservative species (C value of 9) and the existing native plants have responded well to our restoration activities. Our native populations are mainly in two separate areas: 1) The County F roadside, where there are at least 42 separate populations; 2) Unit 11A, the ridge-top bur oak savanna, where there are about 20 plants.

Yesterday I was surveying the vegetation along the new trail in Unit 11A and discovered 5 new lush plants of N.J. tea (obviously fall regrowth) nestled among seed-forming populations of little bluestem grass. The photo here shows a typical one. The habitat here is rocky dolomite and the plants must struggle to find firm places to root.
New Jersey tea fall regrowth among little bluestem. About 20 plants this size were found in this area.

These newly grown plants are somewhat of a mystery to me. I don't think we have ever seen fall regrowth of New Jersey tea before. Perhaps this phenomenon is drought-related? We collected NJ tea seed in this area about a month ago and the now empty seed heads can still be seen among the new growth.

The remnant prairie area where NJ tea is present (Unit 11A) has an interesting legacy. The Bordner map from 1938 showed that this area had been pastured, but because it was so far from the barn, it must have been only lightly grazed. The historic air photos confirm that it was open. However, once farming ceased in the mid 1950s the area gradually filled in, and by the time we began restoration work in 2000 there was a heavy layer of invasive shrubs. We removed all these shrubs, plus any undesirable trees such as cherry and elm (mostly small), leaving any large open-grown oaks or hickories (there were very few). This led to a very open savanna, with a canopy cover of less than 20% (thus, almost prairie).

As soon as clearing was finished, we started burning, first in the fall and later in the spring. About 2005-2006 I found the first evidence that this had been a prairie remnant: several lead plants and NJ teas. It seems likely that the lead plant was also remnant because it is also a conservative species (C value of 7), and because it takes quite a few years to get established from seed, .

Since 2006 the prairie has become much more firmly established. In the most open areas we now have all the Silphiums, Echinacea, Baptisia, and lots of other forbs as well as little bluestem and Indian grass.Also, we are bringing under control the sumac and other invasive shrubs that are also a legacy of pre-restoration years.


Post a Comment

Subscribe to Post Comments [Atom]

<< Home