Allelopathy in pussy toes (Antennnaria sp.)

The production by plants of chemicals that inhibit growth of other plants is called allelopathy, and is surprisingly common. Among species that exhibit this phenomenon are those of the genus Antennaria (pussy toes).

We have two species of Antennaria at Pleasant Valley Conservancy, A. neglecta and A. plantaginifolia, both of which exhibit this phenomenon. They form compact mats which are virtually monospecific, which is a good indication of the presence of allelopathy.

We have several sites at Pleasant Valley in open woodlands where relatively large Antennaria mats are present. The photo above is from a mat at Unit 13A, in an open area adjacent to a white oak woodland. This site had been invaded by aspen, and Kathie and I removed that clone by girdling about 8 years ago. The Antennaria mat probably developed after the aspen were removed.

This site is slowly being converted to prairie. Indian grass is moving in (you can see a small clump in the lower right hand corner of the photo at top), and there are lots of forbs. In fact, I was collecting gray goldenrod (Solidago nemoralis) seeds when I noticed this pussy toes mat. As the smaller photo shows, it is a very compact mat and is almost a pure stand.

I did a literature search for details on Antennaria allelopathy, and found surprisingly little information, although many web sites mention that Antennaria exhibits this trait (without citations).

Of interest is that Antennaria is dioecious (has separate male and female plants).

Making fire breaks for a fall burn

We are planning to burn the north woods sometime in the next few weeks (depending on weather), and yesterday our crew (Amanda, Marci, and Susan) spent most of the day setting the fire breaks.

This is a fairly large burn (about 25 acres), predominantly oak woodland. The fuel is primarily oak leaves, so we need to wait until most of the leaves are down before burning.

The last time we burned this area was October 30, 2008. Details of that burn can be found in this link.

Yesterday we put in two major fire breaks, at the east and west end of the woods. The break at the west end had been used this last spring when we burned the woods at the corner of County F and Pleasant Valley Road. This line was fairly easy to define, as there was a distinct contrast between the burned and unburned sections. (While putting in this line, I had a chance to check the effects of the spring burn and the honeysuckle control work we had done. I'll report on that in a separate post.)

The break at the east end had been used in the 2008 burn, but had become fairly brushed in since then. I walked down the break and put flags at intervals so the crew would know where to go.

The three-person crew worked in the following way: Amanda operated the Stihl brush cutter, using a triangular blade to cut the mostly herabaceous and small woody vegetation. Marci followed behind with the Stihl leaf blower and cleared the trail. Susan took up the rear and cleared the break of larger sticks. There will still be a bit of chain saw work needed, but this can be done on the day of the burn. Also, we will have to do a final pass with the leaf blower on the day of the burn.

The photo above shows the crew finishing up the break at the west end.

The south fire break is a permanent one that we use as an ATV trail, and which serves us when we burn the ridge-top savannas (where we call it the north fire break!). The north fire break for the woodland burn is County Highway F.

The ideal weather for this burn would be a nice Indian summer day following one or two hard freezes. However, since the last month has been so dry, we could probably burn anytime now.

Photo points show 10 year progress

When we began restoration, ecologist Paul West advised us to take photo points at periodic intervals. This sounded like a good idea so I started doing this in the year 2000. Yesterday I was looking down from the edge of the Rocky Overlook and realized that this was one of my photo points so I took several other photos. Of course, the camera technology was completely different. In 2000 I was using a film camera, where yesterday's photos were taken with a digital one, but the formats were reasonably the same.

As the sequence above shows, we have made considerable progress in those ten years. In 2000 we had just finished clearing this part of the south-facing slope. Brush piles are visible, and cut stems of buckthorn and honeysuckle are present. There is a small prairie remnant just under the rocks (mainly big bluestem), but the rest of the slope is mostly weeds, except for a small patch of little bluestem in the lower middle. Several sumac clones are visible, reminding me that in those days we had not worried about this clonal invasive species yet.

The vegetation below Pleasant Valley Road was primarily smooth brome, as we did not plant that area until the fall of 2002 (now called the Valley Prairie).

Along Pleasant Valley Road is a long row of slippery elms, which were not removed until 2002.

It is nice to know we are making progress and that we have the photos to prove it!

Land management: using historical data to detect problem areas

Black Earth Rettenmund Prairie is one of the best prairie remnants in southern Wisconsin yet it still has lots of areas with troublesome shrubs. Sumac, aspen seedlings, gray dogwood, grapevine, etc. occur in certain sites across the prairie, although most areas are high-quality prairie and remain virtually shrub-free. This is so even though this preserve has been burned at least biannually since the mid 1980s (about 30 years).

Fortunately, the Nature Conservancy (TNC) left a historical legacy for this preserve that helps greatly in explaining this situation. At the time that TNC acquired the preserve in 1987 a map was prepared showing the shrub and tree distribution across the site. Also, a number of photopoints were taken, such as the one above of the North unit. Note the large stand of trees.

All of the trees and large shrubs on the North unit were removed by TNC volunteers in the late 1980s and early 1990s. Also, all the large trees along the fence rows and property boundaries were removed at the same time.

When Kathie and I started managing the prairie, we worked with volunteers to remove remaining shrubs from the Saddle, Narrows, and South unit. At present there are no large trees or substantial shrubs anywhere on the preserve. However, there are still many small shrubs, including quite a few sumac clones and a lot of prairie willow. There are also areas where tiny aspen shoots still come up.

As Kathie and I have worked on shrub control with volunteers over the past ten years I have had the TNC historical documents in mind. Once I felt competent in using ArcGIS, I realized that this program would be a perfect tool for connecting present-day shrub distribution with the historical data.

As described in an earlier post, I recently did a GPS survey of sumac on the whole prairie. I then brought these data into GIS as a layer. I then georeferenced air photos from the 1980s, and the TNC map from 1987, and brought them in as additional GIS layers.

Everything lined up beautifully! The points for the present-day sumac stands fell right on top of the historical shrub and tree data from the 1980s.

I should emphasize again that today there are no trees or large shrubs present anywhere at Black Earth Rettenmund Prairie. What the current shrub data show us is where the trees and large shrubs "used" to be.

These data show that the land retains "memory" of what had once been.

These data have important management applications. Historical data, especially old air photos (available for almost any site in Wisconsin) can help one anticipate where problems might arise, and remind one to pay special attention to these areas.

Collecting acorns of red, black, and Hill's oak

Thursday we had a visit from Andrew Hipp of the Morton Arboretum. This was part of a research project he is doing on oak evolution. As part of this project, oaks of all New World oaks are going to be raised in the greenhouse and in a common garden, so large numbers of acorns are needed.

I knew Andrew when he was a Ph.D. student at U.W. In those days he was working on sedges (see his nice book on Wisconsin sedges published by the U.W. Arboretum). Since assuming his position as curator at the Morton Arboretum Herbarium, he has been working on the genus Quercus, especially Hill's oak (Q. ellipsoidalis).

I originally communicated with Andrew after Amanda had discovered that we had Hill's oak at Pleasant Valley Conservancy. See my earlier blog for details. It turned out that for his new project, he was looking for sites where he could collect lots of acorns. This year we have very good acorn production of oaks of the red oak group (red, black, and Hill's), and acorns are falling everywhere.


Since Andrew is the expert on Hill's oaks, I wanted first to have him confirm our identification of this species.

Although the acorns in the photo show distinct stripes, it turns out that this is not the definitive character. Other species can also have stripes at times. One of the best characteristics is pubescence on the inner surface of the acorn cap, which is very dense in black oak and essentially absent in Hill's oak. (See Andrew's 2010 paper published in the International Oak Journal.)

After lunch we went on an acorn collecting foray at Pleasant Valley Conservancy. Since not all trees were dropping acorns at convenient locations, we drove slowly along the North Fire Break, which passes between the savanna and woodland areas. We soon found a very fine red oak specimen with a large number of acorns on the ground.

Of course, not all the acorns had viable seeds. Some had tiny insect holes, and were empty of contents. Others had probably aborted during the acorn formation process. However, one could soon learn to distinguish good from bad acorns by feel. The bad ones, being very light in weight, were tossed aside.








Since we have a lot of acorn-loving squirrels at Pleasant Valley Conservancy, one might wonder why they had not carried all the acorns away. In a good mast year, as this one is, there are simply not enough squirrels to decimate the acorn crop. In fact, this is probably the major reason why oaks exhibit this masting process in the first place. If they produced large acorn crops every year, the population of squirrels (and other acorn eaters) would rise to consume the food supply. Instead, oaks keep the squirrel population low by producing low acorn populations most years. Then comes a big mast year, overwhelming the squirrels, but providing plenty of acorns for production of new oak seedlings. An interesting evolutionary process!

Sumac control at Black Earth Rettenmund Prairie

Despite biennial burns, sumac has remained a significant problem at Black Earth Rettenmund Prairie. We now know how to get rid of it (basal bark with triclopyr). But we need to know where it is, and find the time to work on it.

Today I made a survey of the whole site, looking for sumac clones. This is an ideal time to do this, as all the clones stand out as bright red patches, especially in this nice sunny weather .

I used my GPS to mark the clones, and then transferred the resultant Excel file to ArcGIS. We'll use the resultant map to plot out a strategy for the spraying work.

We divide Black Earth Rettenmund Prairie into four separate units: North, Saddle, Narrows, and South. The North unit is the largest, and is the area that was in the best shape when the Nature Conservancy acquired the property in 1987. In keeping with a widely accepted control strategy, we thus worked on that unit first, and this year sumac is now fairly well controlled. A few volunteer work parties helped, but the main control work was by one of our interns (Lauren), plus some other paid help.

The Saddle has some major clones, especially on the east side near the service lane, and on the west side along the stone wall that separates the Prairie from the adjacent private land. We have already started work here and will try to finish here before the snows come.

The biggest clones are in the Narrows, especially along the fence line. This isn't surprising, since the fence line had been quite wooded when TNC acquired the Prairie, and real restoration work did not get started here until Kathie and I took over management about 8 years ago. (Since our efforts have mainly been invested in sweet clover control, it is not surprising that the sumac has remained a problem.)

There is also a large clone along the fence line in the South Unit, as well as several smaller clones. Again, these clones are in areas that had been wooded.

If we have a light snow year, we might be able to finish the whole site. The nice thing about basal bark treatment is that it can be done any time of the year.

However, our research has shown that you can't eradicate sumac by a single pass. There are always root suckers, so this work will have to continue into 2011 (and beyond...?).

Grasslands Research Network meeting at McHenry County, Illinois

Over the past several days I attended the annual meeting of the Grasslands Research Network (GRN), a Midwestern group of land managers and restoration ecologists involved in prairie and oak savanna research. The meeting this year was held at the McHenry County Conservation District headquarters near Richmond, Illinois. The establishment of the GRN was spearheaded by the Nature Conservancy, but large numbers of others involved in grasslands restoration also attend. Because of the location, this year Illinois was heavily represented.

The meeting was focused (not surprisingly) on establishment of prairies, primarily in former ag fields. I greatly enjoyed Ed Collins talk on how prairie restoration work has changed over the past 25 years at McHenry County Conservation District. Bill Glass' talk on prairie restoration work at Midewin National Grassland, a former U.S. Army site near Joliet, Illinois, was especially interesting when contemplating the immense problems that Wisconsin will soon have converting the Badger Ammunition Depot into a natural area.

The meeting took place at the Lost Valley Visitor Center, a LEED-certified building (Gold level) that is situated in the midst of Glacial Park Conservation Area, a 3,200 acre site featuring a diverse array of prairie, wetlands, savannas, and delta kames. Nippersink Creek, a nice canoe stream, meanders through the wetland. Our registration fee included meals and we could sit in the dining area and enjoy the view while discussing restoration ecology.

A highlight of the meeting was of course the field trips. McHenry County Conservation District has been converting ag fields to mesic and dry-mesic prairie for at least 25 years, and has a wide variety of successes (and a few failures). The District has a large amount of land under management (22,600 acres!), of which over 6,500 acres is of high-quality wetlands, savannas, and prairies. They think nothing of planting hundreds of acres of prairie a year. We were shown prairies planted in the 1970s as well as those planted as recently as 2009. Various planting regimes are used, some more successful than others. Planting is done almost exclusively by tractor-driven mechanical equipment. For some years, the Truax drill had been used but the District is now shifting to the Vicon seed spreader, a Minnesota invention that is adaptable to a wide variety of seed sizes and permits high-rate applications. Since most of the District's restorations are on relatively flat former ag fields, mechanical equipment is very suitable.


McHenry County also has some very nice oak savanna areas, with large open-grown white and bur oaks. In fact, the District has a large program of oak restoration, in attempts to counteract the huge losses of oaks that have occurred since settlement. The Big Woods of McHenry County contained over 30,000 acres of oaks, now mostly gone. A GIS-based study of the history of oaks in the County identified almost 3,000 remaining oak stands, but only 157 of these were 25 acres in size or larger.


The Quercus Project is a county-wide initiative to restore oaks. It involves a bunch of Rs: Recognition (of the problem); Regulation (preserving existing oaks); Regeneration (enlisting the public in a planting program); Restoration (protect remaining oak savannas and woodlots); Resource development (create an endowment fund); and Research (continue to assess the historic and present significance of oaks). The "Oak Keeper" project involves trained volunteers working to gather data at the larger, privately-owned oak woodlands in the county.

Another volunteer activity is working with area youth to promote the next generation of oaks. The District conducts an annual "Acorn Roundup", where kids help collect local acorns for propagation and future oak plantings. Kids also have the opportunity of helping in the work at the Oak Nursery that the District maintains. Also, the kids plant small oak trees at sites around the county. Each child adopts and names his or her oak, and ensures that it is watered each week during the growing season for the first two years.

The funds for land acquisition come from bond issues approved by referendum at general elections. Staff is supported by a dedicated item on the property tax bill (for the Conservation District). Because of the affluence of McHenry County, the return from the property tax is sufficient to support a large staff, in addition to a major intern program (8 full-time interns for 12 weeks) and a number of seasonals.

I was interested in how conservation groups are organized in Illinois at the county level. There are two kinds of county conservation organizations, Conservation Districts and Forest Preserves. Conservation Districts were enabled by legislation in 1963, and a number of counties have been moved to establish them. (McHenry County is the largest.)

The first Forest Preserve system was created in the Chicago (Cook County) area early in the 20th century. A number of other Illinois counties followed along later, although most counties do not have Forest Preserves. According to the enabling act of the Illinois legislature, the goal of the Forest Preserve is "..to acquire... and hold lands containing one or more natural forests or parts thereof or lands connecting such forests or parts thereof, or lands capable of being forested, for the purpose of protecting and preserving the flora, fauna, and scenic beauties within such district, and to restore, restock, protect and preserve the natural forests and such lands together with their flora and fauna, as nearly as may be, in their natural state and condition, for the purpose of the education, pleasure, and recreation of the public..."

I asked several people how Conservation Districts differed from Forest Preserves, and I was told that the main difference was that CDs permit hunting whereas FPs do not.

In September 2008 at Pleasant Valley Conservancy we had a visit from McHenry County Conservation District staff. See my 2008 Blog for a brief description of that visit

Land Trusts

Ron Seely's nice article in today's Wisconsin State Journal (Page 1; Sunday, October 2, 2010) provides a great overview of Wisconsin land trusts and their importance for conservation in the state. Since Kathie and I have used a land trust to protect Pleasant Valley Conservancy, I thought it might be a good time to say a few words about land trusts.

Land trusts have existed for many years (the Nature Conservancy was a pioneer), but in recent years their number has markedly increased. According to the Land Trust Alliance (the national organization that supports the land trust movement), there are 1700 land trusts in the United States, which have permanently conserved over 37,000,000 acres of land. According to Gathering Waters, the organization that supports Wisconsin land trusts, there are more than 50 land trusts in the state protecting over 200,000 acres.

Some land trusts operate statewide, such as the Nature Conservancy and Ice Age Trail Alliance, others are regional, such as the Natural Heritage Land Trust, the Prairie Enthusiasts, and the Mississippi Valley Land Conservancy, and others are very localized, such as Pheasant Branch Conservancy (Middleton) and the Waukesha Land Conservancy. Madison Audubon Society, another land trust that Kathie and I volunteer for extensively, is somewhat of a hybrid, since it is local, but has over 3,000 acres under protection in Columbia and Jefferson Counties.

Last Thursday evening, at Monona Terrace Convention Center, Gathering Waters held its annual banquet and awards ceremony. The Natural Heritage Land Trust was given the well-deserved Land Trust of the Year Award. This organization, spearheaded by a dedicated board (Carla Wright, President) and a skilled executive director (Jim Welsh), has been playing a major role in land protection in south-central Wisconsin. Among its triumphs has been the recent purchase of the Koltes property in the Town of Westport. Negotiations to purchase this critical site have been in the works for a number of years, and have finally been completed. The Koltes land has several fine small prairie remnants, but most importantly provides protection and access for Westport Drumlin, part of the Empire Prairie State Natural Area. Westport Drumlin is an outstanding prairie remnant which, among other things, harbors a fine population of the Federally-endangered prairie bush clover (Lespedeza leptostachya).

Another major land trust in our area (but with statewide and regional significance) is the Prairie Enthusiasts (TPE), and this is the land trust that holds the conservation easement for Pleasant Valley Conservancy (PVC). Kathie and I have worked with TPE for years (since we started restoration work, in fact), and TPE (under Rich Henderson) did the first few extensive prescribed burns on our property.

In 2006 we made two donations to TPE. The first was an outright donation of 37 acres of PVC land that had been owned by our Savanna Oak Foundation. The second was a permanent conservation easement for the rest of PVC, about 103 acres. We also donated $$ to a fund that TPE has set up to use for long-term monitoring of the easement.

Because a conservation easement is permanent, and one never knows what might happen in the future, it is essential that the land trust monitor the property at reasonable intervals to ensure that the terms of the easement have been maintained. This involves insuring that property boundaries have not been violated, and that no improper uses are being carried out. Lives are short, but land goes on forever!

I would encourage those interested in conservation to learn more about the land trust movement in Wisconsin and the United States.