Tom's Blog

Wednesday, May 13, 2015

Turkey vultures at Pleasant Valley Conservancy

We've been visiting the Driftless area of western Dane county for many years but it has only been in the last dozen years that we have been seeing turkey vultures. Having lived in southern Indiana where vultures are very common, my first siting in Wisconsin was something of an event. Now I see them all the time, especially soaring over our steep south-facing slopes.

My experience is not unique. According to Mossman and Hartman, there has been a dramatic increase in vultures in Wisconsin since the 1970's, especially in the western part of the state. Mossman, M.J. and Hartman, L.M. 1992. Turkey vulture nest records from Wisconsin. The Passenger Pigeon, Volume 54: 31-42. 

Vultures are scavengers and cruise over an area looking for road-kill or other carrion. We often see four or more, flying low and nearby and gradually working their way up on the thermals until they are so high that you can hardly see them. Their eyesight is superb, so they can spot carrion from high in the air. Their sense of smell is also outstanding.

With their huge wings, they can fly in almost any wind. Yesterday's strong westerly was no problem and I saw them most of the day, often quite low. Late in the afternoon I saw four birds over the south slope. They gradually rose as they circled on the wind and once they were high each bird went its separate way.

According to Mossman and Hartman, turkey vultures nest throughout Wisconsin. Many of the nest sites are on the ground among rock outcrops. Although we have no confirmed nesting at Pleasant Valley Conservancy, we have plenty of rock outcrops that would be suitable.

Monday, May 11, 2015

Aspen control: long-term survival of buried roots

Aspen is one of those plant species that you can either love or hate! It has extensive commercial value, and its fall color is greatly prized in the Rockies. But it forms large (often huge) clones which make it a menace in prairie and savanna restoration. The individual trees of the clone are connected by rhizomes, which also are responsible for the spread of the clone into new territory.

Unfortunately, aspen cannot be removed by simple cutting, since there are massive numbers of underground buds which are then released from dormancy and send up shoots. Cutting an aspen clone turns a site with a few dozen trees into a forest with hundreds (or thousands) of  shoots, each arising from one of those dormant buds.

The only way to remove an aspen clone is to girdle every tree. Girdling starves the roots of energy and nutrients and the roots eventually die. It may take two years for the girdled trees to die, after which they can be cut and removed. For details of how girdling works, see this link.

Unfortunately, not all the buried roots die. Some of these roots containing underground buds apparently survive and escape dormancy, sending up shoots. How long will these underground roots survive? I used to think "just a few years" but our experience at Black Earth Rettenmund Prairie indicates otherwise. What is the situation?

At the time the Nature Conservancy acquired Black Earth Rettenmund Prairie in 1986 (29 years ago) there was a fairly large aspen clone along the north edge of the Saddle area. This clone was removed by the conventional girdling procedure and by 1990 was completely gone.

In 2002  Kathie and I took over management of BE Prairie. In 2005 we found that a large number of aspen shoots had arisen in this area. Using hand clippers and glyphosate, volunteers cut and treated all these shoots. After that we began burning the Saddle almost every year, either with the North or South unit.

This year (2015) was the first time in some years that we left the Saddle unburned. By early May a large number of new aspen shoots had developed which had obviously arisen from viable dormant buds associated with buried rhizomes. In earlier years, when the Saddle was burned, any new shoots that had developed during the growing season would have been top-killed by the next spring's burn. But this year by allowing a second year of growth, these aspen shoots were now fairly large and easily visible.

My conclusion is that the new shoots have arisen from dormant buds that have remained alive since the aspen clone was eliminated in 1986-1987. Even remaining in the dark all these years, those buds have remained alive.

How long will they yet remain alive? Only time will tell, although I would bet they still have a long underground life yet!

Two aspen shoots treated 5 days before.
The wood lily is  undamaged.
What is the best way of eliminating these new aspen shoots? Since 2005 we have developed a much better and more efficient technique. These young aspen shoots are very sensitive to basal bark treatment with 20% Garlon 4 in oil. Our preferred application method is a sponge on the end of a wooden stick or PVC pipe. The sponge is kept soaked with herbicide from a spray bottle, and treatment consists of swiping up from the bottom along one side of the shoot for a distance of about 6". With this procedure there is no peripheral damage to other "good" species, and within 5 days the treated aspen shoot looks very moribund. Follow-up observations showed that no later new regrowth occurs at the bases of treated shoots. Each treated shoot is gone for good.

Aspen shoots basal barked 5 days before with 20% Garlon 4 in oil. Other species are unharmed.

Friday, May 8, 2015

Trillium grandiflorum carpet in our oak woods.

This is the time of year for Trilliums. We have scattered flowering plants in the oak savannas, but the major display is in the north woods, easily visible by driving slowly along County F.

This year the display is larger than we have ever seen it. It extends along almost a half mile of the lower area of woods. I attribute this large display to the successful woods burns we have had the past 10 years, including last October. As a result of the last burn, the carpet of oak leaves was removed, making it easier for the plants to send up shoots.

We burn these woods in the fall partly to keep from damaging the spring ephemerals. A spring burn in these woods would have a detrimental effect, since it would kill the new shoots. In the fall the Trillium perennating structures lie deep under the soil where the fire cannot reach them. Through the years that we have been doing restoration work at Pleasant Valley Conservancy, we have seen the Trillium carpet continue to spread.
Typical carpet of Trillium grandiflorum in the north woods

Trillium grandiflorum forms short tuber-like rhizomes, which participate in its gradual spread. Seeds are also formed, and are spread by ants. According to some sources, seeds are also dispersed by yellow jackets, other flying insects, and white-tailed deer, which may explain why we find isolated plants scattered through our ridge-top savannas, a long way from the woodland carpet. 

Sunday, May 3, 2015

Red-headed woodpeckers at Pleasant Valley Conservancy

Dale Bonk photo 2015
We get quite a few birders at Pleasant Valley Conservancy, and most of them comment on our red-headed woodpeckers (Melanerpes erythrocephalus). This is a bird species that is in decline in much of its historic geographic range, including Wisconsin. 

Research has shown that this species benefits greatly by oak savanna restoration See: Brawn, Jeffrey D. 2006. Effects of restoring oak savannas on bird communities and populations. Conservation Biology Volume 20 (Issue 2; April), pp. 460-469. In fact, we saw our first red-heads here shortly after we had done the initial restoration on the ridge-top bur oak savannas (Units 10 and 11). 

They definitely breed here, and most years they remain here throughout the year. They almost always turn up in our Christmas bird count.

The map below shows the best area to see red-headed woodpeckers at Pleasant Valley. The two lawn chairs (labeled on the map) make a convenient viewing site.

Why are red-headed woodpeckers declining? Research by William Mueller (Master's thesis, U.W. Milwaukee, May 2002: The biogeography and recent decline of the red-headed woodpecker in Wisconsin.) has shown that the principal factor is habitat loss, including loss of nesting sites and foraging areas.

Mueller also notes that there is evidence that oak savanna restoration and prescribed burning have a beneficial effect on red-headed woodpecker populations by providing optimum nesting and foraging habitat. Preservation of snags is especially beneficial.

Friday, May 1, 2015

Prairie violet and birdfoot violet

Violets are blooming now in the prairies and are close to their peak.

There are two species of violets found in prairies. The one that tends to form patches is birdfoot violet, Viola pedata. The other species, prairie violet, Viola pedatifida, is generally more scattered. Both can be seen now at Black Earth Rettenmund Prairie and Pleasant Valley Conservancy.

Viola pedata, birdfoot violet (Kathie Brock photo)

At a distance, these two violets look very similar. There are some subtle differences in leaf structure, hairiness, and aspect of the flowers, but the best way to distinguish these is from the stamens, which in birdfoot violet are a conspicuous golden color. (See photos above.)

Right now there is a large display of birdfoot violet on the south slope of Pleasant Valley Conservancy, best reached by the trail up from the corner of Pleasant Valley Road and County F.

Don't be confused by the more common violets, such as those found in lawns and weed patches or in woods, whose leaves are whole (undissected).

A great prairie to see large displays of violets is the Nature Conservancy's Spring Green Preserve, along Jones Road off Wisconsin 23, just north of Spring Green, Wisconsin.

Thursday, April 23, 2015

Honeysuckle time

Honeysuckle is one of our more annoying invasive shrubs. However, it is one of the first shrubs to green up in the spring, thus making it easy to spot. Thus, now is a good time (if you have all your burns done!) to seek it out and eradicate it.

Honeysuckle is a multi-stemmed shrub with a fairly shallow root system. In contrast to many other shrubs, it does not form rhizomes. Thus, there is no connection between one shrub and the next. However, every stem that is viable must be dealt with, and larger shrubs often have 15-20 stems.

April 23: honeysuckle green on a hillside

There are two ways of eradicating honeysuckle now:

  • Basal bark treatment with Garlon 4 in oil
  • Cut and treat with either glyphosate or Garlon in water
With either procedure, it is essential to add a dye to the herbicide mixture.

With the cut and treat method, you end up with a lot of biomass that must be stacked and eventually burned. With basal bark, you just leave the plant intact and watch it die. Eventually, the dead stems will dissipate, or burn up during next year's burn. 

For cutting a small infestation, hand loppers can be used, but for large infestations, a motorized brush cutter is preferable, provided there are enough crew members to follow the brush cutter and treat all the cut stems. (A skilled brush cutter can keep three or four people busy treating.

With either technique, it is essential that every stem be treated with herbicide, otherwise the plant will regenerate from the untreated stem(s).

When using loppers with the cut and treat method, make certain that every stem is treated by counting the stems as you cut them and then count again as you treat with herbicide. (The dye will tell you that you have not missed a stem.)

One advantage of the basal bark technique is that if you come across another invasive shrub, such as blackberry or sumac, you can treat that as you go. 

Thursday, April 16, 2015

Final burn of the season

Today our intrepid crew burned the wetland strip, thus finishing our burn program for the spring season. The map shows the area (3.6 acres) burned.

For more details on the burn program at Pleasant Valley Conservancy, and an 18-year summary of burns, see this link.

This has been a challenging year for us to do burns because of the permitting system under which we have to work. There have been a number of low-humidity days during which we are not able to burn, although folks outside of the state-controlled areas could (and did) burn with impunity.

See the text below this map for a discussion and some comments on burning under low-humidity conditions.

This map shows the extensive burn program that was accomplished in spring 2015.
For more details on prescribed burns at Pleasant Valley Conservancy, access this link.

From the Wisconsin Prescribed Fire Council listserv
Burning with low humidity
    Posted by: jsetd
    Date: Wed Apr 15, 2015 6:47 pm ((PDT))

I've been trading e-mails with some fellow prescribed burners about burning in the recent low-humidity conditions.  I'd like to open up the topic to the group, and maybe add some nuance to the discussion.

I'm taking a little flak about my decisions to burn the past two days, so I want to give a little background.  Why would a prescribed fire practitioner even consider burning when the humidity is below 20%?  Doesn't that violate your prescription?  Isn't it irresponsible?

Our prescriptions are based on fire behavior, as predicted by Behave [U.S. Forest Service computer program] fire behavior models for the fuel type and weather conditions, rather than limits on individual parameters.  (We do use parameter limits when dictated by the client, such as DNR or NRCS.)

On Tuesday afternoon we burned two small units.  One was about 2 acres, half good tallgrass (fuel model gr6) and half bluegrass/fescue (fuel model gr3), with a high point in the center.  I measured 75 deg, 25% rh, and light wind 1-2 mph, with a Kestrel 3000.  The unit burned nicely, pulling in to the high point, and smoke went straight up as desired.  The fire was mostly flanking, the head fire behavior was 15' flames and 120 ft/min rate of spread, well within prescription.  The other unit was less than a half acre, no more than 50' across at any point, and was burned with backing and flanking fire with flame lengths under 8'. These units were well suited to burning with light winds and the fire behavior was by no means extreme.

I found out later that the Madison airport was measuring 14% rh when I measured 25%. Measurement accuracy is another lengthy topic but I think that fire behavior is the bottom line.

On Wednesday we had multiple units to burn at a site on the north side of Lake Mendota.  We finished a couple units in the morning with a minimum humidity reading of 33%.  At 13:00 I measured 25% rh, the Madison airport was reporting 20%.  We burned a 3.5 acre unit with tallgrass (gr6) and cattail/sedge (gr8).  The backfire in the gr8 fuel was 8' flames and 50 ft/min spread rate, headfire was 15' flames and 100 ft/min, again well within prescription.

The next unit was a 9-acre gr6 unit.  Measured rh was 27%, Madison airport reporting 17%.  Wind was 4-7 mph. The crew was thoroughly briefed on the red flag conditions, the low rh readings, and the observed and expected fire behavior.  We decided to go ahead, and burned the unit with primarily flanking fire, with 3-8' flames.  We did send some head fire when we had over 100' of black downwind, and had 15-20' flames with 150-180 ft/min spread.  That's pretty big fire but still within prescription and less than we often see in tallgrass with higher humidity and more wind.

All of the units we burned Tuesday and Wednesday afternoon had very good firebreaks, with little or no receptive fuel downwind.  I never felt that we were taking any excessive risks in burning these units, and never felt that the fire behavior was threatening.  I'm not saying that everyone should blithely go out and burn no matter how low the humidity, but it is possible with the right burn units to burn responsibly at these conditions.

Jim Elleson
Quercus Land Stewardship Services