Friday, October 30, 2015

2015 Spring Burn

Bill Collins, Executive Director, Thumb Land Conservancy

On 2015 May 01, the TLC conducted its second controlled burn on the Michigan Road Preserve in Port Huron Township, Saint Clair County. This year, the Port Huron Township Fire Chief, Craig Miller, gave us permission to conduct the burn on our own, without their supervision. Our performance last April with the fire department probably helped in this decision. The purpose of the burning is to kill invasive Glossy Buckthorn, and encourage fire-tolerant vegetation that likely dominated this landscape prior to European settlement, before fires were suppressed. Accomplishing these two goals will increase native woodland species abundance and help prevent long-term degradation of the plant community.

Since taking over stewardship in 2011 of the Saint Clair County Road Commission and Pro-Tel Development preserves, collectively referred to as the “Michigan Road Preserve” along the east side of Michigan Road, between Dove Road and the Canadian National Railway, in Port Huron Township, it was clear that control of invasive Glossy Buckthorn is the big management issue out there. Glossy Buckthorn – Rhamnus frangula, recently renamed as Frangula alnus, is a small tree or shrub native to Eurasia and North Africa. It was introduced to North America about 200 years ago, first as an ornamental hedge plant, and later as a planting for wildlife and other conservation uses. Like so many other shrubs brought to North America for these purposes, including Common Privet - Ligustrum vulgare, Tartarian Honeysuckle - Lonicera tatarica, and Autumn-olive - Elaeagnus umbellata, Glossy Buckthorn became highly invasive, especially in open forests and shrub swamps. It forms very dense shrub thickets that shade-out and displace nearly every other plant species that once grew in the same area.

Glossy Buckthorn - Frangula alnus dominance in the west end of  the preserve.

The best control for Glossy Buckthorn is pulling the smaller saplings and cutting the larger, usually combined with herbicide applications. This is very labor-intensive, requiring a lot of people and time to make significant progress against large areas of Glossy Buckthorn such as on the west sides and interior shrub swamps of the Michigan Road Preserve. Herbicide has the disadvantage of not always being so selective in which plants it kills. We are aware that some land managers have had tremendous success in controlling Glossy Buckthorn in shrub swamps by burning. This is usually more effective in open wetlands where there is more herbaceous growth and therefore, more fuel for burning. Except during autumn leaf fall, there is not typically a large amount of dry fuel on the ground of mature forests, and therefore, burning is more difficult.

Another aspect of the burning is that, to some extent, the northern plant community on the Michigan Road Preserve and across similar sandy soils in the Port Huron area, is fire-dependent to some degree. Oaks - Quercus, Paper Birch - Betula papyrifera, Low Sweet Blueberry - Vaccinium angustifolium, Wintergreen - Gaultheria procumbens, Bunchberry - Cornus canadensis, and other species on the upland sand ridges on the preserve all thrive in response to burning. Fire should help to restore some of the natural structure of the vegetation among other benefits.

Bunchberry - Cornus canadensis (white flower) and Fringed Polygala - Polygala paucifolia (violet flowers) along the south edge of the burn area on 2015 May 15, two weeks after the burn.

We decided to try burning on the west side of the Michigan Road Preserve to see how the Glossy Buckthorn would be affected in the swamp forest. We considered burning in the shrub swamp portions of the preserve, but we didn’t want to decrease the Speckled Alder – Alnus incana cover which appears to be competing with the Glossy Buckthorn, and we don’t want to open these areas to further invasion by Reed – Phragmites australis which dominates the lower wetter areas.

Speckled Alder - Alnus incana and Royal Fern - Osmunda regalis in the western edge of the shrub swamp. Here it appears to be competing fairly well with Glossy Buckthorn - Frangula alnus and Reed - Phragmites australis.

So far, the 2014 and 2015 burns appear to have decreased Glossy Buckthorn density. Because of delayed resprouting, it’s difficult to determine the final outcome until the burn areas have been observed multiple years. There has also been an increase in Black Cherry - Prunus serotina seedlings, but these are unlikely to persist as they mature due to the shade of the forest canopy. It appears that we are seeing an increase in generally northern herbaceous vegetation that likely benefits from fire, including Bracken Fern – Pteridum aquilinum, Fringed Polygala – Polygala paucifolia and Canada Mayflower – Maianthemum canadense, but it is too early to determine. A major consideration is that the forest probably lacks the original diversity and abundance of species that would have spread after fire, and so we may not see an optimal response until new species are introduced by seeding or transplanting. Other limiting factors include continued grazing by deer and edge forest effects due to the close proximity of non-forested land to the north and west.

2015 Burn Photographs

A nice burn up on the sand ridge with lots of dry oak leaves.
Glad we prepared good control lines because this fire burned along at a fast clip even upwind.
Left to right: TLC President Cheryl Collins; our first TLC Intern on her first day, Alex Roland; and Alex's friend Brook. All did a fine job and we kept the fire well-contained.
TLC Board Member, Dan "The Man" Rhein.
Dan Rhein holding the north boundary.
Smoky tip-up mounds. These mounds of sand were formed over centuries by large trees falling over and uprooting the soil. Most of the mounds date back prior to European settlement in North America and some could be as old as 8,000 years.
At this point in the burn, it was mostly large branches and logs smoldering.
This is the burn area on 2015 May 15, two weeks after we burned.
The contrast of burned (background) and non-burned (foreground) ground along the south limit of the burn area.
An Eastern Garter Snake - Thamnophis sirtalis out in the warm spring air near the south edge of the burn area.
Witch-hazel - Hamamelis virginiana inside the eastern burn area. It was leafed-out and appeared to survive the burn with no problem.
Eastern edge of the burn area, up on a sand ridge, showing what appear to be hybrids of Northern Pin Oak - Quercus ellipsoidalis and Black Oak - Quercus velutina (larger dark trees), scorched along the bottom trunks but otherwise unscathed.
Eastern edge of the burn area, up on a sand ridge, showing what appear to be hybrids of Northern Pin Oak - Quercus ellipsoidalis and Black Oak - Quercus velutina (larger dark trees).
Bracken Fern - Pteridium aquilinum appears to be particularly happy after burning. This is the new "fiddle head" recently emerged from the ground and growing taller.