Category Archives: Plants

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

Timberhill Plants: Milkweeds in Their Natural Habitat

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Of the plant families at Timberhill the milkweeds are one of the most numerous.  Eight species,  Fourleaf milkweed (Asclepias quadrifolia), Purple milkweed (Asclepias purpurascens), Common milkweed (Asclepias syriaca), Butterfly milkweed (Asclepias tuberosa) Tall green milkweed  (Asclepias hirtella), Sullivan’s milkweed (Asclepias sullivantii),  Whorled milkweed (Asclepias verticillata), and Swamp milkweed (Asclepias incarnata) are found here. Blooming in succession from May through August their copious nectar  attracts butterflies, hummingbirds, honeybees and other insects.  All  are also  larval food plants for Monarch butterflies.  (Monarchs will only breed where milkweeds are found.)

Since we have seeded no wildflowers at Timberhill these plants grow only where Mother Nature planted them.  The first to bloom each year is the rare Fourleaf milkweed.   A savanna specialist it first bloomed at Timberhill on a wooded ridge near the base of a white oak  in May, 2010, seventeen years after we began restoration.  Nearby plants included Dwarf larkspur and Purple twayblade.  Although ranked G5, globally secure it is listed as infrequent to rare in south central Iowa. In 2010 there was only one slender stem of bloom and it did not set seed, This year there were 2 blooming stalks with six umbels of bloom.  We have our fingers crossed that it will set fruit.

Fourleaf milkweed, Asclepias quadrifolia

One has only to follow the great spangled fritillaries to find Purple milkweed. Stimulated by fire it is  a common occurrence at Timberhill.   In the open woodland A. purpurascens plants are usually single, whereas they are usually clustered in sunny oak openings and woodland edges.  In some parts of the U.S., especially the Northeast Purple milkweed is in serious decline.   It is estimated that only 30 plants remain in the entire New England region.

Common milkweed blooms at the same time as A. purpurascens.  At Timberhill it grows only on disturbed ground and is particularly abundant where we have done construction. This makes no difference to the butterflies.  On a recent sunny afternoon we counted five great spangled fritillaries, three tiger swallowtails, three monarchs, two skippers and various bees in the A. syriaca patch south of the house.

Butterfly milkweed prefers full sun.  It usually begins blooming in our prairie remnants after three prescribed burns and is most abundant in  our West Creek unit.   12 plants now bloom in one site that supported only dense cover of Eastern red cedar when we purchased this unit in 2005.  According to Julian Steyermark, Flora of Missouri it also occurs in dry open woods, but I’ve never seen it in the Timberhill woodlands.

Although there are ten or more plants of Tall green milkweed in our south meadow this variety is most abundant in the mesic prairie remnants.   Along with Sullivan’s milkweed it prefers the West  Creek prairies that are watered by hillside seeps.

The least conservative species Swamp milkweed and Whorled milkweed are the last to bloom.  Swamp milkweed  prefers wet feet and is abundant in the old fields along the Brush Creek bottom and at the edge of the West Creek wetland.  The West Creek plants are quite different from the old field plants in that they have woody stems and are the size of small shrubs.   Whorled milkweeds, on the other hand prefer the dry prairie and woodlands in the east savanna.

The use of fire to restore woodlands and prairies is a legitimate concern regarding insect survival.   However, we have learned that annual low impact dormant season fires not only stimulate the plants butterflies need for nectar and larval food but leave plentiful plant debris to harbor the next season’s brood. It scuds over the surface leaving dried stalks and other dormant insect habitat intact.

 

Timberhill Plants: Moehringia (Arenaria) lateriflora, (Grove Sandwort)

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Grove Sandwort, Moehringia lateriflora

I was walking through one of our prairie remnants when I first spotted the small white flowers of Grove sandwort.  Atop a slender peduncle that extends laterally from the main stem these easily overlooked flowers were barely 1/4 inch wide.  But it was spring before most of the other  forbs were in bloom. The tail end of the morel mushroom season, I was heading for a dying elm that had produced abundant fruiting that season.    I paused to take a closer look at this plant.  A small perennial forb,  Moehringia lateriflora (Grove sandwort)  is a member of the pink family.  The specific epithet lateriflora means “flowering on the side” referring to the habit of the flowers which bloom beside the main stem.  A many branched plant with  elliptically shaped one inch long leaves Grove sandwort seldom grows over 8 inches tall.  The Iowa Floristic Quality Database of coefficients of  conservatism assigns it a 10, indicating that it has very strong fidelity to a specific habitat.

Grove Sandwort blossom

In Iowa, according to Eilers and Roosa, Vascular Plants of Iowa, it occurs frequently in the Paleozoic Plateau and the Iowan surface of northeast Iowa. and is infrequent in southeast Iowa.  In Missouri it is known only from six northeastern counties.  According to Julian Steyermark’s  Flora of Missouri, it “occurs mostly in acid soil of upland woodland of dissected oak-hickory-clad hills, crest of ravines, rarely in low woods.” Although it has never been documented to occur in south central Iowa it is also abundant in the Timberhill  West 40 and West Creek units.  Other plants growing in the same remnant prairie  include Wild onion, Sweet scented bedstraw, Partridge pea, Tick trefoil, Big blue stem grass, Sedge, Showy goldenrod, Purple prairie clover, Canadian milk vetch, Mountain mint, Bastard toad flax, New Jersey tea, Wild strawberry, Spiderwort, Pale beard tongue, Pale spiked lobelia, and  Spring larkspur.

Prairie before restoration

When we purchased the  prairie remnant where Grove sandwort is now abundant the land  was completely overgrown with Eastern red cedar and elm trees.  Before that it had been heavily grazed by sheep and cattle.  Yet this very conservative plant survived the neglect and was restored after management by thinning and prescribed fire.  Whenever we find a conservative plant such as this, outside of its recorded range, we are thankful we didn’t introduce any seeds or plants.  One can be very pleasantly surprised by what shows up on its own.

Surprising morels

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Cluster of yellow morels in Hickory Grove

Our neighbor, Doyle, introduced Bill and me to the annual spring rite of hunting for morels.  He has been harvesting these delectable fungi since childhood and is a true expert.  Our first year at the farm we followed Doyle through the riparian woodland along Brush Creek. Instead of looking down at the ground, he looked up at the leaves of silver maple trees. They were just large enough that one could make out their distinct shape. Satisfied that the maple leaves indicated it was time, he walked slowly around the base of a silver maple looking for the first morels of the season.  Pushing aside the leaves with a stick he showed us the clusters of small gray morels. Thanks to Doyle,  Bill and I eventually learned to find these early morels and the later fruiting yellow ones ourselves.

In southern Iowa morels begin fruiting in mid to late April.  Depending on the weather the season lasts from two to four weeks.  Since they tend to fruit in the same locations each year we counted on harvesting them under the silver maple, elm and hackberry trees along Brush Creek every year.  However, one cold wet spring we couldn’t find a single specimen and had to search for them elsewhere.

That was the  year we learned that morels can be a delicious side benefit of timber stand improvement and annual prescribed fire. Our West 40 unit was heavily overstocked with elm and Eastern red cedar when we purchased it in 2001. After thinning and annual prescribed burns I was not surprised to find abundant fruiting of morels around some of the elm stumps.  Morels are often associated with elms for three years after the trees die. Some stumps produced over fifty morels the first year.   What has surprised me is that morels have continued to fruit in the West 40 every year since.  Our most reliable site is a prairie remnant where the earliest morels of the season fruit among the hoary puccoon and wood betony.  They aren’t as plentiful as they were seven years ago, but we usually harvest what Doyle calls, “a good mess”.

2011 was a particularly sparse morel season in south central Iowa.  Morel hunters complained that there was no fruiting in any of their usual spots.  They complained that morels could only be found in sites where they had never fruited before.  That was certainly true at Timberhill.  This year the most abundant fruiting was in the Hickory Grove where we’ve never found any morels. The only trees in this woodland are shagbark hickory and young oak sprouts yet we harvested five pounds of morels there this season. Even before thinning there were no elms in this woodland.   Heavy fruiting of black morels is common one  year after forest fires in the western states and one wonders if prescribed fire at Timberhill also stimulates fruiting of grey and yellow morels  in Iowa.