The Nature Conservancy in Minnesota

Species
Individual species have adapted differently to fire and the effects of total combustion and residual heat. Fire managers tailor their prescriptions for different objectives including achieving high mortality on colonizing brush species, such as hazel, and understory trees like ironwood and maples, while minimizing the effect on fire-adapted species such as oak and pine. Altering different factors and the timing of fire allows the prescribed burn to achieve the most influence on these species in their early bud/flower stages in late spring.

Additionally, fire managers wait until fuel and weather conditions are appropriate to further increase the success of the fire. Altering ignition patterns to increase or decrease residual time can change the vegetative effect of the fire.

To learn more about fire and its effects on different species, the U.S. Forest Service has a website with a plant and animal species database and current research about the effects of fires of differing intensities on those species.
http://www.fs.fed.us/database/feis/plants/index.html

Potential Natural Vegetation

1. Dry-Mesic Pine/Oak Forest (118,000 acres within landscape)
Stand Replacing Fire: 250-500 year rotation
Stand Replacing Wind: 1,000-year rotation
Surface Fire: 40-year rotation

Disturbance models have predicted that 50 percent of the landscape was in mature to late successional growth stages (76 years). Aspen and birch dominated early successional growth stages while oak and pine species were most abundant in mature-late successional stages. Currently 82 percent of this system is in the 76-year growth stages. Pine species have declined precipitously while aspen, birch, oak and maple species are the most abundant in the system.

Native Plant Communities: Fdc34-central dry-mesic pine-hardwood forest

2. Dry Pine Forest (44,000 acres within landscape)
Stand Replacing Fire: 60-120 year rotation
Stand Replacing Wind: 1,000-year rotation
Surface Fire: 40-year rotation

Disturbance models indicate a relatively even distribution of growth stages. Aspen and jack pine dominated the early and mid-successional growth stages (76 years), while red and white pine were most abundant in the mature-late successional stages. Jack pine has declined significantly while aspen and oak species have increased substantially.

Native Plant Community: Fdc23-central dry pine woodland

3. Dry-Mesic aspen-oak (58,000 acres within the landscape)
Stand Replacing Fire: 300-400 year rotation
Stand Replacing Wind: 1,000 year rotation
Surface Fire: 50-100 year rotation

Disturbance models show that ~55% of the landscape was in mature-late successional forest conditions. Aspen, birch and oak species were most abundant in the early to mid-successional stages (<76 years). White pine, red oak and maple species along with birch and aspen comprised the older growth stages (>76 years). At present, approximately 80% of the landscape occurs in the <76 year growth stages. Aspen has increased while white pine has declined in importance. Oak and maple show similar abundance values, however, oak regeneration is minimal.

Native Plant Communities: Mhc26-central dry-mesic oak-aspen forest with subtypes: oak-aspen-red maple and red oak-sugar maple basswood

Photo Credits:
(left): The height and percentage of canopy foliage scorched is one measure of burn severity when evaluated post fire effects of fire. Fire behavior patterns and their effects can be determined after the fire and used in writing future plans. © Kent Montgomery/TNC
(right): TNC Forest Ecologist Mark White instructs Americorps team members in proper monitoring techniques for determining litter and duff measurements and other fuel measurements. © Colin McGuigan/TNC

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