SALEM, OR -- Oregon’s Department of Agriculture has made permanent rules to severely restrict the use of an herbicide believed to be responsible for killing trees near Sisters. The ODA concluded that applications of aminocyclopyrachlor (ACP) from 2013 to 2015 left more than 2,000 ponderosa and lodgepole pines dead or dying along Highway 20. ACP is sold under the name "Perspective," made by Bayer. The company asked for a delay in permanent restrictions, after temporary rules were imposed in September. 

The ODA’s now-permanent rule bans the chemical’s use on rights of ways, natural areas, ditches and canals, and a host of other locations, and prohibits trees affected by Perspective to be used for compost or mulch. It also can't be applied by air.