In North America, burning is often used in prairie management and restoration projects. A study was undertaken in three upland prairiesin Willamette Valley, western Oregon (USA; 123°17′W, 44°41′N) to determine usefulness of burning to restore native plant communities and its affects on seedling establishment of native and non-native species.
The study sites represented three common prairie types in the region: dominated by annual non-native grasses (e.g. medusahead Taeniatherum caput-medusae; rough dog’s-tail Cynosurus echinatus and soft brome Bromus mollis); dominated by perennial non-native grasses (primarily tall oatgrass Arrhenatherum elatius); and a native bunchgrass site.
In late September 1995, four treatments (burned, clipped to stubble and hand-raked to remove litter, burned with litter re-spread, and an untreated control) were applied to 2 x 2.5 m plots (randomized complete block design; 8 blocks). A grid of 10 subplots (5 x 5 cm) was established per plot. Seed of common non-native and native prairie species was hand-sown, one species (10 seeds) per subplot. Two were unsown to assess seed bank emergence.
Seedlings establishment was recorded in mid-December 1995, mid-March 1996 and mid-May 1996.
Sown seeds established at 2-65%, depending on species, treatment and site. Seedlings of test species in unsown subplots were generally zero or negligible (<2/plot).
In both the annual and perennial non-native sites, burning significantly improved native (7 of 8 species), but not exotic (2 of 7 species increased), seedling establishment over unburned plots. Litter was reduced thus promoting seedling establishment. Burned plots had two to five times as many native seedlings as unburned plots. Burn treatments on the bunchgrass site significantly increased short-lived non-natives seedling establishment only.
Results suggest that at prairies similar to the annual and perennial non-native grass sites, prescribed burning followed by sowing native seeds may be an effective restoration technique for improving seedling establishment. Burning without sowing native seed could result in domination by exotic species derived from the seed bank.
If using or referring to this published study, please read and quote the original paper, this can be viewed at: http://onlinelibrary.wiley.com/doi/10.1111/j.1526-100X.2005.00071.x/full