10-15-2012 Planning Commission Packet

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� 2 CONTROL OF EXISTING BUCKTHORN Common buckthorn (Rhamnus cathartica) is established along north boundary of the property. � Seed carried by birds, has helped introduce this species throughout the region.� Buckthorn generally does well in moderately shady forested areas. Buckthom can usually be found � throughout�the Twin Cities in fragmented woods or city lots and invades first from forest edges • and slowly moves inwards. Buckthorn has been successful at establishing itself in these woods due to its long growing season, rapid growth rate, and copious fruit production. This establishment of buckthorn has multiple ecological detriments such as out competing native plants, disrupting the forest structure, and reducing plant species diversity. These detriments have lead to major efforts to prevent the spread of buckthorn and restore the forests to an ecologically productive and functional state. Proper management and yearly follow-ups will be necessary for this site due to the seed bank left behind by buckthorn which can regenerate for up to 6 years after removal has taken place. To eradicate the existing buckthorn, cut the plants and treat the stumps with herbicide such as Roundup (or its counterpart in wet areas, Rodeo). Application should be full-strength. When cutting the larger buckthorn, place flags near the stump so that stumps are not missed when the chemical treatment is applied. Herbicide treatment needs to occur within two hours of cutting to be effective. � If cutting is to take place in the winter, flag buckthorn so that similarly appearing native plants such as black cherry are not mistaken as buckthorn. One application of glyphosate (Roundup or Rodeo) on the outer growth rings of a freshly cut stump in August or September has proven to be effective, though other treatments are lrnown to work as well (Converse 2003). Applications during the autumn or winter are also proven to be successful. Do not apply glyphosate or other chemicals during the spring because this is considered the spring-flush growth period in which sap is ruruiing and the plant is using stored energy. Therefore, the chemicals that are applied in the spring will not make their way down to the buckthorn's roots. Glyphosate is a nonselective herbicide that will kill non-target plants if it comes into contact with them. Managers should exercise caution during application, and not spray so heavily that herbicide drips off the target species. For areas that are adjacent to wetlands on site, chemical treatments must be labeled for aquatic use such as Rodeo. Basal bark application of Garlon 4� (LJniversity of Minnesota Extension Service 1999) is another option for a chemical application. To prevent dense re-infestations we advise careful monitori.ng of the site every 1-2 years. Upon the discovery of newly established plants it is recommended that the newly emerged plants be pulled out of the ground, including the roots, immediately. There are specialized weed pullers to facilitate pulling larger plants. Pulling is the preferred option when there are localized infestations of small plants; thorough monitoring should ensure early de.tection of newly emerged seedlings. During the buckthorn removal process it is important that soil disturbance is kept to a minimum and that akeady established native ground cover species are kept intact. By reducing this disturbance, rejuvenation of native plant species will increase and soil erosion will be kept to a minimum. On some sites, planting may not be required. Instead of planting, wait 2-3 years �-: 1� � + �