Imagining a Restored Savanna

 Picking up on the theme of oak savannas, here are a couple scenes from the top of Mt. Tammany in the Delaware Water Gap dividing New Jersey and Pennsylvania. Lowbush blueberries (red) grow beneath scattered chestnut oaks.

At Bennett Place, remnant thickets of lowbush blueberries survive half-buried in accumulated leaves and pine needles, beneath the post oaks and shortleaf pine. These photos show how the Bennett Place woodland might look if the savanna there were restored through thinning out of weedy tree species, allowing enough sunlight to reach the blueberries.

Native Plants the Bennetts Might Have Used

One interesting theme to explore at Bennett Place is what native plants might have been used by the Bennetts and others in the 19th century. Growing naturally at the site in sunny areas is Yucca filamentosa. The photo shows native Yucca being cultivated at Thomas Jefferson's Monticello, possibly for the fiber that can be extracted from the leaves.

In the woods at Bennett Place grow low-bush blueberries and wild grape. Currently they are too shaded to bear fruit, but they may well have played a dietary role back when the woodland was more open.

The second photo shows a vineyard at Monticello. The native muscadine grape (Vitis rotundifolia) was widely grown in the States. Wikipedia refers to the scuppernong as being the same species as muscadine, but larger and green.

I once encountered a patch of delicious muscadines next to Ellerbe Creek a mile downstream of Bennett Place, growing like a curtain high and wide on trees next to a service drive near Hillsborough Road and 15-501. The patch was lost during the expansion of I-85, but testifies to the abundant fruit the wild grape can bear.

This third photo, taken at a scout camp in the pinelands of New Jersey, shows an open woodland with an understory of lowbush and highbush blueberries growing in sandy soil. Among the plants this woods and Bennett Place have in common are post oak, white oak, blackjack oak, shortleaf pine, bracken fern and the blueberries. The soil at Bennett Place was described by the soil service as having some sandy elements more typical of areas further east, in the coastal plain. The Bennett Place woodland would look very much like this if the historically open canopy was restored, allowing enough sunlight in for the blueberries to bear fruit.

Witness Trees at Bennett Place

This past winter, there was some bad news and some good news about the old post oaks (Quercus stellata) scattered through the thirty acres of woodland at Bennett Place. The bad news was that one of the trees was accidentally cut down during some harvesting of firewood. The good news is that we were able to get a local tree expert to count the rings.

Multiple counts showed the lost post oak to have been at least 146 years old. (The marker at the middle of the cross-section says "1864".) Such trees, termed "witness trees" because they were alive at the time of the historic Civil War surrender, are of great historic and ecological value, and quite a few still remain in the woods.

The tree rings from recent decades were very close together, reflecting the slowing of growth as faster growing weedy tree species have increasingly competed with the post oaks for sunlight and water. The ascension of other tree species could be interpreted as natural succession in the forest, but what is more likely is that the historic natural plant community was a "fire climax" forest, in which tree species whose thick bark allowed them to survive periodic natural or Indian-set fires would have remained dominant. The leaves of oaks and pines are very resistant to decomposition, and essentially act as a persistent fuel source ready to fuel a fire as it moves across the woodland floor. The spacing and age of the post oaks and shortleaf pines suggests that they were part of a savanna landscape of scattered trees and rich herbaceous understory sustained by periodic fire.

Since fire has been excluded from the landscape, the only way to restore and sustain the historically authentic landscape of post oaks, shortleaf pine and understory of low-bush blueberries, wildflowers and grasses would be by management to discourage the weedy tree species that would not have survived the fires. It's not clear how much longer the witness trees will survive without management, since some have already died.

To help with this effort, contact me at the email address shown in "show my complete profile" on the right of this page.

A Piedmont Prairie Planting

Increasingly, historic sites seek to recreate historically authentic landscapes. With the permission of the current site manager, a friend and I transplanted some native wildflowers to create a miniature piedmont prairie along the edge of this fenceline.

In the background is the visitors' center for Bennett Place. Included in the planting were little bluestem, split beard bluestem, sugarcane plume grass, Yucca, hyssop-leaved thoroughwort, and several species of goldenrod.

Bennett Place staff have kept the area unmowed, allowing the native plants to grow and bloom over the summer.

Iris, Bluets and Gama Grass

Here are a few more of the many species of native wildflowers to be enjoyed at Bennett Place. This miniature iris, Iris verna, was found growing near Bennett Place, along Hillsborough Road under a power line. Like many prairie wildflowers that need sun, it survived under the powerline because of the infrequent mowing.

When the owner decided to develop his Hillsborough Rd. property, the Ellerbe Creek Watershed Association organized an effort to rescue as many of the wildflowers as possible. Bennett Place, just a quarter mile away and with similar soil, seemed the perfect place to give this and other native wildflowers a safe haven.

Bluets grace the field at Bennett Place in the spring.

One of my favorite prairie grasses is eastern gama grass. It typically grows in wet areas, such as ditches, but is found here next to the gazebo at Bennett Place. Some have speculated that it was one of the ancestors of corn, of which gama grass's large seeds and silky flowers are reminiscent.

Heritage Trees of Bennett Place

It blends in with the general green, but this tree standing at the edge of the field at Bennett Place may well have been growing here when the largest troop surrender of the Civil War took place here in 1865. It is one of a number of post oaks in the Bennett woods, easily identified by its cross-shaped leaves.

Like many species of oak, post oaks grow best in areas that receive periodic "cool" fires, which pass through the understory, converting thick mulch to fertile ash and killing competing species that don't have the oak's thick, protective bark. Natural fires were augmented by those set by Native Americans, and later on by sparks from passing trains.

Though Bennett Place is preserved, these heritage trees are threatened by competition from weedy tree species that have sprung up in the absence of fire. Dense shade and thick accumulations of mulch have diminished the wildflowers and dwarf blueberries that once thrived here.

Another species of heritage tree at Bennett Place is the shortleaf pine. Note the plate-like bark, which can be distinguished from the more furrowed bark of loblolly pines.

Some years back, the Ellerbe Creek Watershed Association installed interpretive signage at Bennett Place with information about the heritage trees, and the savanna plant community that still lingers here.

Special Native Plants at Bennett Place

Lewis's Heartleaf, a rare species of ginger, was found growing in an area that the Bennetts are believed to have used as a dump. This makes sense, in that it would likely have been spared the plow and thereby have left the native flora undisturbed.

In the second photo, if you look closely you can see a dwarf sundew (reddish) in the midst of the moss. The presence on this upland piedmont site of sundew and sphagnum moss, both of which would more normally be found in bogs down in the coastal plain, is yet another of Bennett Place's mysteries. One explanation can be found in the kind of soil found here, which has very unusual properties.

This Large Whorled Pogonia (Isotria verticillata) was found growing near Bennett Place on land targeted for development. Ellerbe Creek volunteers rescued it from the bulldozers and brought it to Bennett Place. The two sites share the same soil type, which makes Bennett Place the best refuge for this and other unusual wildflowers in the Ellerbe Creek headwaters.

Update, 4/9/10: The Pogonia, planted along a nature trail by Josh Rose years back, survived its first year or two, but has not been seen during visits in the past two years. It may well have succumbed to drought or trail maintenance activities. Josh's discovery of the plant on similar soil less than a mile from Bennett Place does at least documents that it was part of the historic plant community. Josh also found a ladyslipper orchid growing along a power line even closer to Bennett Place.