Timberhill East Savanna: Columbine Ridge

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People often ask me what plants comprise Timberhill oak savanna.  My answer is always the same:  it depends on where you look.  Every ridge, prairie opening and ravine has a different complex of plants.   Plant composition is dependent on too many factors to be consistent throughout a site.  Soil texture, moisture, geography, percent of canopy cover and disturbance history are only a few of the many factors that determine plant composition. This fact was demonstrated to me by Gerould Wilhelm on one of his visits to Timberhill;  in a comparison of plants in several adjacent transects no transect had more than 50 percent of the same species.

Columbine blooming under scattered white oaks

Walking through our open oak woodlands I am constantly surprised by the way plants arrange themselves.   Last week I followed a deer trail east from our driveway.  Beyond the weedy driveway border the trail skirted a blackberry patch then led me across a ravine to the next ridge. There I stood transfixed by the sight of hundreds of columbines in full bloom.   Columbine is found throughout our woodlands, but they are usually scattered, never in a dense stand such as this.

Bastard toadflax

Looking around I wondered how columbine had picked this spot.  Other than columbine three species, lousewort, Bastard toadflax, and purple twayblade orchids, were the most abundant plants on this ridge. These are my “big three” plants because they always indicate that floristic quality is increasing. Short heads of lousewort crowded with yellow blossoms formed a dense cluster at the perimeter of the columbines, whereas they were only widely scattered within the stand. Uphill, slender leafy stems of Bastard toadflax dominated the understory. Underfoot purple twayblades were so abundant that I couldn’t help but step on them.  They formed clumps of up to thirty specimens.

Purple twayblade showing corm from which the plant sprouts

This little orchid is not very conservative.  Its coefficient of conservatism is 4 indicates that it is not limited to high quality habitats.  However, no matter how conservative, all orchids require appropriate soil fungi.    Orchid seeds have no stored carbohydrates and cannot germinate without a fungus to nourish them through the early stages of development.  Without a host soil fungus there would be no purple twayblades at this site.  What the twayblades were telling me was that the soil fungi, a vital component of the rhizome layer were well established on this site. Occasional specimens of yellow false foxglove, a very conservative plant, were proof that the floristic quality was increasing.

I expect that the columbines on this ridge will decline as more conservative plants become well established.  But for now Bill and I relish their abundance.

TIMBERHILL BACKSTORY

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In 1994, when I was told that Timberhill was “a rare oak savanna” I had no idea what that meant.  In the years since as I watched the land recover from years of neglect I have learned what that means.  For those embarking on their own restoration, I thought more detail about what oak savanna means here in south central Iowa might be of interest.  That is not to say that this restoration should be used as a model.  Each site is unique;  if restoration is limited to thinning and burning it will respond with its own assemblage  of plants and animals.

The diversity of the 200 acre Timberhill landscape with dry, open ridgetops, steeply wooded slopes,  riparian creek borders, mesic prairie openings, hillside seeps and wetlands is founded in Decatur County geologic history.  In the Southern Iowa Drift Plain, Decatur County is on high land almost midway between the Mississippi and Missouri Rivers. Erosional processes have cut the glacial plain into high narrow ridgetops, dissected by narrow ravines.   The major streams flow north-south; their tributaries don’t deviate much  east or west.  Travelling east to west one must cross a series of alternating ridges and valleys which early settlers described  as the ‘devils washboard’.  North-south one can usually find a ridge road (Howell and Smith 1915).   For example, in this photo showing Timberhill topography a trail used by migrating Indians and early settlers followed the central ridge north then turned northeast along  a secondary ridge down to Brush Creek.  Presettlement the creek was on the same level as the adjacent ground and easily navigable on a horse or horse and buggy. (I didn’t believe that this was actually the route followed by Indians until I found a perfectly shaped arrowhead on the trail.)

In this photo showing Timberhill topography the Indian- pioneer horse trail followed a ridge line .

The soil surface is old, dating back to the last glaciation, 500,000 years ago. It comprises a thin mantle of loess-like top soil over fine to coarse sand with some gravel below. Under this layer is gumbotil, a dark sticky clay which locals call ‘hard pan’. Unable to penetrate the hard pan,  ground water flows laterally through the upper soil layers until it exits in seeps where the soil surface and water vein intersect.  The seeping hill slopes are the perfect  habitat for conservative plants such as lady’s slipper orchids.

Because of its sharply dissected landscape, much of Decatur County has survived the plow . Although they may have been heavily grazed or are badly overstocked, the unplowed woodlands are highly restorable.  The biggest problem is controlling erosion.   However, native plants and seeds retained in the understory will respond to restoration.  As the graminoids and perennial forms are restored they absorb nearly all precipitation  into the soil.  All that is needed is thinning of the overstocked woodland and prescribed fire. In this photo one can see how restoring the native plant cover is controlling erosion.

Restored native plant cover is controlling erosion. The head cut in the lower right is no longer moving uphill.

(I’m going on spring break. The next post will be on May 7.)

H.F. Bain, “Geology of Decatur County” in Howell and Smith. 1915. History of Decatur County.
Jean C. Prior, 1991. Landforms of Iowa. Iowa City: University of Iowa Press. 

THE SEASON BEGINS

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First bloodroot

After the unusually mild winter of 2012, it’s hard to predict what the growing season will bring.  Will this weather pattern continue or will a cold, wet spring follow the warm winter?  What new species will we find at Timberhill this year? Each year is different, yet each the same. The fluctuations of our weather may go from one extreme to the other but the natural rhythm does not change.  In the east savanna bloodroot and trout lily are always the earliest spring ephemerals to bloom.  Although  they are blooming two weeks earlier than we have ever recorded,  they are always the first to bloom. Rue anemone is usually a close second.  Spring beauty. bluebells, and wild hyacinth will soon follow. Everything follows a natural order no matter what the weather.

Wild hyacinth plants emerging

What does change are the plant communities.  Before we began restoration  the late Dorothy Beringer visited Timberhill.  As we walked down a nose slope overlooking Brush Creek in the east savanna I asked her why she thought this hillside  was a monoculture of little bluestem grass.  There were no forbs whatsoever.  She told me it was because the bunch grass was so thick there was no room for anything else. After we implemented prescribed fire, however, that all changed.  Yellow pimpernel, lousewort, and other conservative forbs became established there.  Small red waxy cap mushrooms, Hygrocybe cantharellus, now fruit under the little bluestem each summer.  (Studies in Ireland have shown that waxy caps fruiting in grasslands are indicators of high quality habitat.)  The indigo milky cap mushroom, Lactarius indigo,  which is said to grow only in mixed deciduous and coniferous woodlands also fruits there occasionally as do golden chanterelle mushrooms.

The vector for these changes is a mystery to me. All I know is that sunlight and fire stimulate them.  As Bill and I  look forward to another year we wonder what surprises nature has in store.

READY TO BURN

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We had an escape last year; the prescribed burn in our West Creek unit escaped into adjoining property.  West Creek burns are always tough because there is so much fuel. Management has  stimulated bunch grasses and sedges throughout this unit, particularly since we took out the red cedar, shingle oaks and honey locust trees.  Sand Creek serves as a fire break to the east but prairie and open woodland border the other directions. Last year the fire escaped into a prairie to the west. Our experienced crew quickly got it under control, but Bill decided we needed to upgrade our equipment.  We have a 15 gallon water tank with sprayer for the ATV and a 25 gallon spray tank for the Ranger utility vehicle, but Bill decided we needed an all-in-one slide in sprayer unit.

Wildland Slide-in Unit

He researched units until he found the perfect one to meet our needs.  Features of the Wildland slide-in unit he purchased include:

Size that fits our Ranger utility vehicle

At 250 pounds, it’s light enough for two men to slide it into the Ranger bed.

Baffles in the 50 gallon L-shaped polypropylene to prevents water from shifting on steep slopes.  Furthermore, the tank is low enough that it doesn’t interfere with vision and the low center of gravity minimizes tip-over risk.

A detachable pump and engine to obtain water from a remote source

A 100 foot-long kink and abrasion resistant hose that mounts on top of the tank out of the operator’s line of vision. At 18 pounds it’s much lighter than a rubber hose.  The hose connects to foam applicator;  the foam surfacant lowers the water’s surface tension, allowing it to spread and penetrate more easily.

Removable cargo tray for extra gas and tools.

All we need now is cooperation from the weather.

MEDICINAL MUSHROOMS

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When I tell people that I’m collecting mushrooms in summer or fall, they usually reply, “I didn’t know that you could find morels at this time of year.”  The only wild mushrooms most people harvest is the morel which fruits in late April and early May in Decatur County. They are missing many other edible mushrooms that fruit throughout the growing season from late May until hard fall frost. Not only are many of them delicious, but some have been used for thousands of years in herbal medicine.  They are reputed to help treat numerous ailments. Studies have proven some of these benefits, but there is still much speculation about how effective they are.

Oyster mushrooms fruiting from downed hickory

Oyster mushrooms, Pleurotus ostreatus, fruit in overlapping shelves on dead elm and hickory throughout the growing season.  A choice edible this white or grayish brown medium-sized mushroom, has soft gills that run down the short stem. Besides being a choice edible it contains the statin lovastin. A number of animal studies have shown that eating oyster mushrooms can lower cholesterol. Research has also shown that this species helps fight various cancers. To cook, sauté the mushrooms with garlic in butter and olive oil, and toss with pasta and parsley.  They can also be substituted for cultivated mushrooms in many recipes.

Hen of the Woods, Grifola frondosa

Hen of the Woods, Grifola frondosa, grows in clusters from the base of oak trees in the fall. A perennial, it often grows in the same place year after year.  This soft, fleshy polypore is composed of individual overlapping fruiting branches that constitute a large fruiting body, as much as 60 cm across. Also known as maitake, it is prized in traditional Chinese and Japanese herbology. Not only does it enhance the immune system, but it has also been shown to inhibit growth of cancer cells, regulate insulin and blood pressure, and lower cholesterol.

Reishi mushroom, Ganoderma lucidum

Reishi mushroom, Ganoderma lucidum, reputed to be the mushroom of immortality, has been used in traditional Chinese medicine for over 2000 years. The varnished red, kidney-shaped cap of this corky polypore has white pores underneath. I find it fruiting from the same downed silver maple year after year. The most highly prized of the medicinal fungi, reishi, is used as a tonic to support general wellness and vitality. It is also reputed to inhibit the growth of malignant tumors, treat liver diseases, treat viral diseases, lower blood pressure, and help regulate cholesterol.  It’s bitter taste and corky texture do not make it suitable for eating.  Instead, it is prepared as hot water extract: soak overnight in water to soften the flesh, then cut into thin slices and simmer in boiling water, covered for two hours. Sweeten and drink as a tea.

When collecting fungi for consumption it is important to make sure of the identity of each species.  Some mushrooms are highly poisonous. To learn more about collecting fungi attend a foray of your local mushroom club. (listing is available at the NAMA website)

Many other fungi commonly found in the Iowa woodlands have a wide spectrum of beneficial properties. You may find a complete listing in Medicinal Mushrooms by Christopher Hobbs. (Botanica Press, Summertown, Tennessee. 1986)