Category Archives: Plants

Taking Stock

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As year end approaches Bill and I will compile an annual report of our  progress toward restoring Timberhill.  The report will list new species collected in 2011, changes we have observed, and  advancement toward our restoration goals.  In order to make the best use of our time in the coming year we have to prioritize. In 2012 restoring the wetland and fen on the east and west sides of West Creek will continue to be the highest priority.  It is also our greatest challenge.   This site includes spring fed bottom wetlands and a hillside fen. We have enough experience restoring overstocked savanna to know how to proceed and what to expect.  But restoring wetland is beyond our expertise.  We have no idea what to expect. So we’re learning through trial and error and using instinct to guide us.

When we purchased the West Creek unit in 2004 the creek bottom, wetland, and fen were overgrown with honey locust and invaded by multiflora rose. The hillside above the pioneer spring was a dense stand of Eastern red cedar.  Furthermore, erosion from uphill cornfields had cut a deep ravine that bisected the West Creek unit. At the bottom of the erosional run was a small stand of prairie cord grass and sedge.  In 2011  the erosional run continued to decrease as the cover of  prairie cord grass and sedge increased.

Timberhill aerial with blue line indicating creek

In 2004 we introduced annual prescribed burns to control invasive plants and tall shrubs,  stimulate return of native plants, and restore the natural hydrology.    Other than girdling and removal of honey locusts we did no further clearing for three years, giving our  annual dormant season burns time to control some of the invasives.  In winter, 2007, we thinned the remaining trees except the elms which we left for morel habitat.  (They will die of their own accord and produce morel mushrooms as they die.) In August, 2007,  we burned the downed Eastern red cedars on the hillside above the pioneer spring.  Burning them while the surrounding plants were still green made the fire easy to control.  Not only have remnant populations of  native forbs, sedges and  warm season  grasses increased  on that hillside, but the contours have softened.  What had been a sharp drop to the creek has become a gentle slope.  Most interesting have been the changes around the pioneer spring.  The land between the spring and the creek is now dotted with seeps.

 

Seep that has developed below the pioneer spring. Note water dripping on right side.

On the east side of the creek we have made some progress, but it’s very slow.  The biggest problem is running fire through this area.  Only small sections at north and south end have burned.  In the north burned section Long-scaled tussock sedge, Carex haydenii, is out competing the other plants and slowly moving through the brush to the north fence line.  Fire has also stimulated clumps of Wood reed, Cinna arundinacea,  under the shingle oaks at the south end.  But the center portion is still a tangle of dead elms, invasive vines and multiflora rose.

 

We've made little progress in this center portion of the east side.

The most interesting new species we found this year was an Albatrellus, a polypore mushroom.  Polypores are usually found growing on wood, but this species was terrestrial, fruiting from the ground in the West 40 woodland,   It is also mycorrhizal, having a symbiotic association with trees.  A search of   the Iowa State University herbarium fungi database lists only two Albatrellus records:  1927 collection in a Webster County woodland and a 1936 Johnson County collection.   The specimens I collected were too immature to key.  Hopefully, this interesting mushroom will fruit again next year when I will know enough to let it mature before collecting.

Albatrellus mushroom

Buckeye Butterflies Breeding at Timberhill

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Common Buckeye

One of the most common butterflies at Timberhill is the Buckeye (Junonia coenia), a medium sized brown peacock butterfly. Distinguished by the bold pattern of eyespots, white bars and orange cell bars on its wings this species is  found throughout the United States (except the northwest) but is most common in the southern states.   Buckeyes do not overwinter in Iowa and specimens seen here are ones that have migrated north from the south in late spring.  It is presumed that they migrate south in the fall.  The description in Butterflies of Iowa poses the question do they breed in Iowa? They do at Timberhill.

In order for butterflies to breed a site must have the plants the larvae feed on.  Of those preferred by Buckeyes Bastard toadflax, wild petunia, and slender false foxglove are all abundant at Timberhill.   In late August and September  the longitudinally striped caterpillars with their pattern of branching spines were easy to spot feeding on slender false foxgloves, Agalinis tenuifolia.  These annuals are stimulated by fire and are particularly abundant in the old corn field in our West Creek unit.  Large clumps bloom throughout the field  in late summer.

Buckeye larva on slender false foxglove

Below is a photo of the hard outer shell of a Buckeye chrysalid from which an imago, the perfectly formed butterfly, emerged in September, 2011. Buckeyes have 2-3 broods between May and October.    The chrysalid stage lasts only two weeks in the fall. Presumably that gives the adult stage plenty of time to head south.  However, we were still seeing occasional adult specimens as late as November 4.  Shouldn’t they have headed south by then?

Buckeye chrysalis

A Timberhill Tour: Hidden Prairie

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West 40 with Hidden Prairie

One of the pleasures of restoring Decatur County overstocked savannas is finding hidden treasure.  The Hidden Prairie is such a treasure.  Completely surrounded by woodland it had remnant populations of many conservative prairie plants such as purple prairie clover.  Bordered by our south property line, it covers a west facing hillside overlooking West Creek, part of a forty acre track we purchased in 2005. The property to the south is a mature overstocked savanna remnant, but there were no veteran oak trees on our portion of the land surrounding this prairie.  Only 75 year old shingle oaks. (It may have been logged off in the nineteenth century.)

At the time of purchase Rattlesnake master dominated the upper portion with more mesic plants such as bottle gentian at the lower end above the creek bottom. A stand of shingle oaks extended into the prairie dividing it into two parts.   We began managing it before we owned it.  Whenever we burned the West 40 unit we used West Creek as a fire break.  Since the Hidden Prairie is between the West 40 and West Creek it has been burned annually since 2002. After we purchased it we cut down the shingle oaks that divided the prairie and thinned a stand of shingle oaks between the prairie and the south fenceline.

The above photograph of the Hidden Prairie was taken before restoration. Since then it has doubled in size. The Rattlesnake master has declined. Prescribed burns have stimulated the warm season grasses and sedges.  Virtually all rainfall is now absorbed into the soil and the natural hydrology has been restored.  Even in dry weather plants have a consistent supply of water from the groundwater seeps.  The shingle oaks cannot tolerate these mesic conditions and are dying.  The Hidden Prairie is gradually extending its border uphill to the east.

Hidden Prairie in June

We have no idea how far it will go. There are two more prairie remnants along the south fence line, above (east)of  the Hidden Prairie.  All that separates them are shingle oaks.  As the shingle oaks die I assume the Hidden Prairie will become linked with the other remnants. A few young bur oaks are becoming established there as well.  Perhaps this prairie has a savanna in its future.  In any case it is fascinating to watch the transformation.

A Timberhill Tour: The Southeast Woodland

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The Southeast Woodland comprises approximately 20  acres in the southeast corner of Timberhill.  It borders a ridgetop meadow in the center of the property. From there the sharply dissected ridges drop steeply to Brush Creek, our east boundary.  Timber stand improvement, i.e., removing the midstory weed trees and thinning the pole timber was completed there in 1998.  Since this unit contained lot of red oak which species is highly susceptible to oak wilt we anticipated higher than normal mortality and left sixty trees per acre, more than in other units.

SE Woodland before prescribed burns

We didn’t burn this unit until 2000 because there was no firebreak.  Then we found an old trail just inside the south property line. It was a mess.  Several large trees blocked the trail.  Between that and the heavy brush it took a friend with a Bobcat, Bill with a clearing saw and chain saw to cut our way to down to Brush Creek. Then we recruited volunteers for the first prescribed burn in 2001.  This unit has been burned every year since.

SE Woodland after 10 prescribed burns

Recovery of the understory plants has been inconsistent.  After three prescribed burns yellow ladyslipper orchids appeared clinging to the side of seepy bluff overlooking the ravine at the north end. Pockets of other conservative plants such as false hellebore are scattered through the rest of the woodland, but much of the understory is still in early stages of recovery.    The canopy is denser here than in the East Savanna and ambient light is less than 10% of full sunlight.  That may be why it is taking so long.

False hellebore, Veratrum woodii

But  ectomycorrhizal fungi that have fruited here since we began managing this woodland have compensated for the lack of floristic quality.  (Ectomycorrhizal fungi have a symbiotic association with the roots of a vascular plant.  Mushrooms collected in the SE Woodland have all been associated with white oaks. ) After the first prescribed burn the woodland north of the trail/firebreak was filled with deadly destroying angel mushrooms.  After three burns these fungi were replaced by various species of brittlecap, milky cap and Amanita fungi.    In 2007 we were thrilled with a heavy fruiting of king bolete, a choice edible.  We also had several nice fruitings of golden chanterelles, another choice edible. The SE Woodland mycoflora has become more interesting since then.  Each year a new bolete species has fruited here.  (The underside of Bolete mushroom caps have pores instead of gills. Bolete spores are released from inside these pores.)  Several have been species new to Iowa records. The latest was Leccinum subglabripes, with bright yellow pores and stalk that stains red.

Leccinum subglabripes

A diverse population of fungi is essential to oak savanna quality.   In a woodland it is the fungi that bind all the other organisms together.  Mycelium, the threadlike vegetative structure of fungi, links plants together and regulates the flow of nutrients and water. Each species delivers specific benefits to its host plant.  The more diverse the ectomycorrhizal fungi in a woodland, the healthier the woodland.

Eastern Red Cedar: Before and After

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That Eastern red cedar is a noxious invasive of Midwest prairies and woodland is universally accepted.  It outcompetes other plants for water, consuming up to 30 gallons per day.  The thick, side branches block light from reaching the understory. It reduces soil microbial activity by robbing  the soil of nutrients.   Native plants cannot grow under these conditions. Here in Decatur County Eastern red cedar was first planted in cemeteries.  Seeds  dispersed by cedar waxwings, robins and woodpeckers soon spread aggressive invasive throughout the county and it soon covered unmanaged prairies and woodlands.   The sprouts are easily controlled by frequent fire, but mature trees must be cut and burned.

What is not universally accepted is that a cedar choked prairie can recover following tree removal and prescribed fire.   It is assumed that no native plants will  be left under stands of mature Eastern red cedar. That, once the trees have been removed, the only way to restore the habitat is to seed native plants.

Felled Eastern Red Cedar

At the time of purchase our West Creek unit had several dense stands of Eastern red cedar interspersed with prairie openings.  We initiated control with two annual prescribed fires.  Fire reduced the lower branches of the trees and  weakened the roots making them easier to remove.  We cut down the trees in winter, 2006.  The following midsummer the felled trees were surrounded by warm season grasses.  With so many highly combustible dead trees we chose to burn them in early August when the surrounding green plants would make the fire easy to control.

Burning Eastern Red Cedar

Although we did no seeding in just four years a diverse prairie has replaced the dense stands of eastern red cedar.  One site, a north facing hillside now has sixteen butterfly milkweeds growing under the eastern red cedar skeletons.  Mountain mint, blazing star and many other native prairie plants have also become well established.   Not only has the prairie been restored but the newly released plants provide plentiful nectar for the fritillaries, hairstreaks and  butterflies that are constant visitors to the restored prairie.

Butterfly Milkweed under Eastern red cedar skeleton