Tom's Blog

Tuesday, November 29, 2011

Getting seed mixes ready

We have almost 200 species of seeds collected, and now is the time to construct seed mixes. Most of these won't be used until spring (after the burns), but some will be used now, so all the mixes need to be made. This is mainly Kathie's responsibility, and my job is to figure out how many acres of each seed mix we will be planting. I use GIS for this, which is convenient but not essential.

Our possible seed mixes are: dry prairie (DP), dry-mesic (DM), open savanna (OS), woodland, wet-mesic (WM), and wetland, but this year we need only DM, OS, WM, and woodland. The assignment of each species to one of these categories is based mainly on the data of Curtis, as collated and summarized by Rich Henderson in a very useful Technical Bulletin of the DNR. (Now out of print, but available on-line at UW-Madison Digital Collections.)

Some species fit in more than one category. For instance, stiff and showy goldenrod are in DP, DM, and OS, New Jersey tea is in DM and OS, and New England aster is in DM, OS, and WM. So when the mixes are made, we have to take that into consideration.

The first thing to do is determine how many acres of each habitat type will be planted. Then a ratio between the various categories is calculated. This year, the numbers are: DM, 2; OS, 1; WM, 0.5, woods, 1.

A large bag is labeled for each category. Starting with A (Amorpha canescens) and going through Z (Zizia aureus), the available seed for each species is split and distributed into each bag. For instance, since lead plant is being used only in DM and OS, twice as much lead plant seed is put in the DM bag than in the OS bag. The actual distribution does not need to be very precise, and is done by handfuls.

It takes three people to do the mixes, one with the master list, two doing the distributions.

The DM and OS seed mixes will be used mainly for areas where we have removed invasives such as sumac, sunflower, and pale Indian plantain, although we are also replanting (supplementing) several prairie and savanna areas. The WM mix will be used for the Barn Prairie and Crane Prairie, with a small amount in the wetter part of the Pocket Prairie.

The woodland mix will be used in the road cut along County F, where some areas have been newly cleared. This mix will also be used in an area of the north woods where a lot of honeysuckles were removed.

Reseeding areas where invasives have been removed makes a lot of sense. If the invasives have been in the site for any period of time, they have shaded out many of the desirable species. Removing the invasives from an area creates a hole where other undesirable species can get established. Such undesirables include annuals such as foxtail grass, giant ragweed, and fleabane, which may flourish. The newly planted seeds may take several years to develop into substantial plants, but eventually they should take over, and the annuals will subside.

Because the number of species available differs from year to year, we prepare a new master list each year. The seed list for 2011, an Excel file, has 196 species. I would be happy to send a copy of this list to anyone who wants one. Send me an email.


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