Tom's Blog

Tuesday, November 24, 2015

White indigo (Baptisia alba) tumbleweeds

This is the time of year when white indigo (Baptisia alba) seed stalks break off and blow away. They act like "tumbleweeds", getting blown across the prairie. The seeds of this legume are heavy, but many of them remain in their pods for long after maturity. Thus, their behavior seems to play a role in seed dispersal.

Once the stalk breaks, the seed head becomes top-heavy, ensuring that the seeds get placed near the soil where they can do the most good.

White indigo seed stalks spontaneously turn upside down when the stems break
All it takes is a strong wind to carry these seed stalks far from where they have started. It's neat to watch them rolling across the prairie.

Plants of quite a few species are dispersed as tumbleweeds. Most are found in farther west, in the Great Plains and deserts. As far as I know, white indigo is the only species of the midwestern prairies that acts as a tumbleweed.

The other species we have, cream wild indigo (Baptisia bracteata) is built closer to the ground and is not a tumbleweed.

B. alba in full bloom
White indigo is a very showy plant (C value of 8) and is highly desirable in tallgrass prairies. It prefers mesic sites, although we also have lots of it in our more open oak savannas. Fortunately, it is fairly easy to get established.

At Pleasant Valley Conservancy we have a remnant population of white indigo on the North side of Toby's Prairie. This population was in an area that just escaped the plow (in the days when Toby's Prairie was an ag field). We collected and seeds and planted them in most other areas of the Conservancy. Although it takes a few  years for them to get started, once they are going they take care of themselves.

Friday, November 20, 2015

Using fire in a rational prairie/savanna restoration program

This is the time of year to be thinking about spring burns.

We have been burning at Pleasant Valley Conservancy for almost 20 years now, and the program set out below is based on our experience. We've learned a lot from doing burns with TNC, MAS, Dane County Parks, and TPE. But we've especially learned a lot from our own burns. I've always taken careful notes of each burn, and made a detailed map and narrative. I started using GIS eight years ago, and this has been very helpful for creating professional-looking maps of burn plans and burn results.

When we started prairie and oak savanna restoration at PVC, we made the mistake of burning before doing any significant brush removal. (We were poorly advised.) Fortunately, those early burns were almost completely ineffective, since there was nothing to carry a fire. I say "fortunately", because if they had been successful, all those large buckthorn and honeysuckle plants that would have been killed would have resprouted large numbers of new shoots, making them lots more difficult to eliminate.

We did have successful burns of two small prairie remnants that had no brush problems.

Fortunately, our tree and brush control program got ahead of our burns.

Here are the steps I envision in a rational prairie/savanna restoration burn program:

  • Start with your very degraded remnant(s)
  • Don't burn
  • Get rid of all the undesirable woodies by cut-and-treat or basal bark. Brush removal and tree removal move ahead together
    • Brush
    • Invasive trees
      • Walnuts
      • Aspen (by girdling)
      • Cherry
      • Box elder
      • Elm
  • As soon as the site is clear, burn to make way for the seeds
    • If the fire doesn't carry well because of sparse fuel, force it to burn by doing extensive interior lighting
  • Overseed with appropriate understory forbs and grasses
  • Start annual burning to get the natives well established
    • Continue overseeding after each burn for another year or two
  • Continue annual burning for 5-10 years (the longer the better)
    • Use foliar spray after each spring burn to kill woody resprouts 
    • Gradually the site will improve
    • Modify your fire technique as the years go by
  • Once the site is well established (but not too soon) switch to a period of 2 burn years followed by 1 off year.
    • The off year is to give the residual brush (which will certainly still be present) a chance to get big enough so that it can be easily found and killed with herbicide.
    • Basal bark herbicide is probably the best, since it can be done 12 months of the year, although large clonal patches are probably better cut with a brush cutter. Be sure to treat every cut stem.
  • Continue the 2 on 1 off cycle indefinitely, always monitoring the brush and making sure it has been eradicated
The above protocol should be modified depending on conditions, but the basic rationale should remain the same. For a large site, it is best to restore small units (5-10 acres at most).

Monday, November 16, 2015

Strategies for restoration of prairie remnants

This post is based on thoughts arising from an extensive blog post of Steve Packard's, which can be found at this link.

"Our true natural areas are often tiny remnants in seas of corn, brush, or development. What's the best management for such treasures?"

Packard presents three hypotheses that I list below. He discusses each one, indicates that none of them are based on significant research, and notes that little testing is going on. "Some people argue that individual managers should be empowered to follow their own preferences." " staff and stewards come and go, new people change the protocols...."

"Hypothesis A: The best approach is to save the best there is---and then leave it alone as much as possible."

"Hypothesis B: The best approach is to save the Grade A and B sites and restore them---and as much land around them as possible."

"Hypothesis C: One good approach is to find large Grade C's (preferably with some high quality remnants included) and restore full diversity."

Black Earth Rettenmund Prairie is one of our better remnants and certainly a Grade A. It is also one that I am very familiar with because Kathie and I have been managing its restoration since 2001.
In the early days, we sent out postcards to
announce work parties

In the early years, the Nature Conservancy had used a modified version of Hypothesis A. Save the best there is, but carry out frequent burns and extensive woody plant control. Also, some limited herbaceous weed control (wild parsnip only).

When Kathie and I took over, we continued the brush control work, but also initiated extensive herbaceous weed control, not only wild parsnip but (especially) sweet clover. We had wild parsnip gone in a few years and sweet clover greatly reduced (although unfortunately still with us).

But as the work party announcement shows, we immediately started a major effort in seed collecting, with the seeds used on areas where brush had been removed. Note that only seeds that are collected at BE are used here. There is no introduction of new species. The activity is called "interseeding" or "overseeding."

Although we did not verbalize it in the early days, our understanding was that the seed bank in formerly woody areas was impoverished, and allowing species to establish on their own was unlikely to work very well. Surprisingly, little interseeding had been done at BE, even in areas where extensive aspen clones had been removed

According to the few research studies that have been done, the seeds of most prairie species do not last long in the soil. The main species that do are those that form hard seeds such as legumes. Thus, without interseeding, one is hoping that seeds will drift in from other parts of the preserve. But the seeds of many prairie species are not wind- or bird-born. (Think of all those species making really tiny seeds, such as shooting star, culver's root, alum root, prairie cinquefoil, etc.)

There are lots of great ideas in Steve Packard's blog post, and I strongly recommend that it be read!

Friday, November 13, 2015

Common milkweed (Asclepias syriaca) flourishes in oak savannas

The new Monarch butterfly initiative of the NRCS is focusing extensively on milkweeds.

Monarchs lay their eggs on milkweeds, where their caterpillars grow and pupate. Three species of milkweeds seem to be of prime importance in our area: Asclepias syriaca (common), A. incarnata (swamp), and A. tuberosa (butterfly). Because common milkweed is so easy to grow, and has a wide range of habitats, most of the work is on this species.

At Pleasant Valley Conservancy we have lots of milkweeds (seven species, to be exact). Not surprisingly, common is the most common! However. Although it does grow in our prairies, it really flourishes in several of our oak savannas. Who knew that this prairie plant "prefers" savannas?

The photo here was taken looking west on what we call the Mid Savanna Trail. In the distance (red arrow) Kathie can be (barely) seen immersed in about 1 acre of milkweed plants. (Since common milkweed is rhizomatous, it is not surprising that it spreads well. Check this link for an interesting example of how common milkweed rhizomes work. )

Red arrow; Kathie collecting milkweed pods along the Mid Savanna Trail
For the past two years Kathie has gone "all out" to collect common milkweed pods for a Monarch initiative at Madison Audubon Society's Goose Pond Sanctuary. In 2014 she collected over 4000 pods and in 2015 over 1000. Since each pod has more than 100 seeds, this gives some idea of how many seeds she has collected. The seeds from these pods are removed and cleaned by MAS volunteers, and the seeds then get distributed to new prairie sites at GP.

The site shown in the photo is one of our outstanding oak savanna habitats and one of my favorite sites. We usually stop here on our field trips for a lengthy discussion of how oak savanna restoration activities work. This location is easily reached from the trailhead by crossing the Pocket Prairie and walking uphill to the trail junction. Here you are in the midst of venerable open-grown white oaks that have been here at least since the 1850s.

Among other things, colleagues of entomologist Prof. David Hogg have been using this same site as a convenient location for collecting eggs for their Monarch cultivation project.

Wednesday, November 11, 2015

Driftless area geology at Pleasant Valley Conservancy

One of the reasons Pleasant Valley Conservancy (PVC) is so scenic is because it is in the "heart" of southern Wisconsin's famous Driftless Area. The rugged hills exist in our area because they are capped with an erosion-resistant rock type called the Oneota Dolomite.

Underlying the Oneota is a less erosion resistant formation called the Jordan Sandstone. Both the Oneota and the Jordan have outcroppings at Pleasant Valley.

Back in 2002 we were fortunate to have geologist Bob Dott visit PVC and create for us a geological cross section. Bob and I covered the whole Conservancy and he located the various rock layers. 

Among other things, Prof. Dott discovered a contact point between the Oneota and the Jordan along the side of the Ridge Trail that descends from the Far Overlook. The attached map shows the approximate location of this contact. (It is permissible here to take a short exit from the trail in order to see this geological location. Take care, because the slope is very steep here!)

ArcGIS map of the west end of PVC, showing the various trails.

The easiest place to see the Jordan Sandstone is the large outcrop in the Quarry. (See photo) The reason the Quarry exists is that about 50 years ago the Jordan Sandstone removed here was use to create Cedar Hill Lane, just across County F. The trail from the Quarry to County F follows the old road used to bring the rock down.

The rock face consists of the Jordan Sandstone. See map above for location where this photo was taken.

Geology is important in controlling the ecology of PVC. Because the bedrock is so close to the surface, it plays a major role in soil formation. Because the Oneota dolomite is rich in calcium and magnesium carbonates, its overlying soil is calcium/magnesium-rich and alkaline, making it favorable for calcophilic plant species such as buckthorn. Soils formed on the Jordan, well seen at the east end of PVC (the East Basin, especially) however, are quite acid, with pH values around 5.0 to 5.5.

Wednesday, October 28, 2015

Seeing green this time of year is bad!

By late October most of the native species have either turned color or lost their leaves. Anything green now is almost certainly nonnative (bad). This is a great time to survey for invasive brush which, because they are still green, really stand out.

Buckthorn bush in the midst
of the S slope prairie 
Buckthorn and other nonnative shrubs: Buckthorn, in particular, really stand outs, as the photo shows. Note that this buckthorn plant is a new vagrant in a tall grass prairie that has been burned annually for the past 15 years. This shows two things: 1) Fire will not eradicate buckthorn; 2) The buckthorn rootstock has a long persistence, since this plant is new in 2015 in an area that had been cleared of buckthorn in 1998!

However, this is probably not a good time to use a foliar spray on this bush. At this late in the season, one can't be certain that the herbicide will still be translocated to the roots (which is essential if this bush is to be eradicated). However, basal bark with 20% Garlon 4 in bark oil will work 12 months of the year, and this is how Amanda dealt with this plant.

Nonnative herbaceous perennials still green: Lots of nonnative herbaceous perennials retain their green color long after native species have senesced. This includes such culprits as garlic mustard, hedge parsley, sweet clover (1st year plants), mullein, burdock, catnip, and motherwort. This is an excellent time to foliar spray these plants with 2-4% glyphosate. The rule is that only green leaves will take up glyphosate and translocate it to the roots. Since most native species have senesced, there is no danger of peripheral damage.

This time of year, all of our Solo backpack sprayers have been put away for the winter, but the Solo 2 gallon hand-held sprayer was still available and worked well on this small area. It took about 15 minutes to deal with this patch. A nearby patch of catnip was also treated.

Large motherwort patch near the parking area. This area was highly disturbed due to road building
and has been a difficult area for us to restore. Motherwort and catnip are continual problems.
Note the handy Solo sprayer. 
An exception to the "rule of green": A number of native species do exhibit the phenomenon of "fall regrowth" so a few native green plants may still be present. These are usually found as rosettes near to last summer's senesced stems. Generally, these are easy to spot and should obviously not be sprayed.

Saturday, October 24, 2015

Upland boneset, a Special Concern species

Upland boneset (Eupatorium sessilifolium) is a Special Concern species in Wisconsin and Threatened in Michigan. As the Wisconsin State Herbarium map shows, it has a narrow distribution in the southern part of the state. It has a Coefficient of Conservatism of 9.

(Although it is a "classic" savanna species, for some reason it was excluded from the Cochrane/Iltis Atlas of the Wisconsin Prairie and Savanna Flora.)

Note that E. sessilifolium can be easily distinguished from the much more common tall boneset (E. altissimum) because of its sessile leaves (see photo below).

In the early days of restoration at Pleasant Valley Conservancy we had only a single stand of 5 stems at the SE corner of Unit 8. We raised seedlings in the greenhouse and planted transplants in likely areas in the Conservancy. Most of these transplants grew and we now have this species in a number of good savanna sites. In addition, it has spread on its own from the original stand and there are now many plants in other parts of Unit 8.

We have been working with upland boneset for over ten years now, and have found that despite the lush flowers and seed heads, germination of seeds is below 5%. However, the species transplants well, so that those seedlings we have been able to raise generally become well established. The population shown in the photos here was part of a transplant series that has flourished in Unit 19C.

This species may be more common in southern Wisconsin than the map below shows. (Because it is a State-listed species, detailed locations are not given in the Herbarium website.)

Update 26 October: Yesterday I discovered a new large patch of upland boneset just south of the South Firebreak in Unit 5. Kathie and I counted over 20 flowering stems. Nice to know this species is spreading on its own.

The sessile leaves are an unmistakable characteristic of Eup-sess.