Green Horizons

The herbicides, Pathway and Tordon RTU, are not effective when applied using the hack-n-squirt method. While vertical movement is good (left), there is no lateral movement (right image showing healthy, living tissue on either side of the hack). This leaves enough living tissue to allow the tree to live.

Folk say that catching my mistakes is akin to shooting fish in a barrel, and last month some of my astute professional foresters had a field day. The barrel was “The Toolbox” and the fish were my recommended methods of applying our commonly used herbicides. So, to set the record straight, the correct recommendations are below. Under the column “Common Use,” I have listed the methods in order of use.

My most glaring error was recommending to apply picloram with the hack-n-squirt method. The images here, that I took in a study conducted by the Kansas Forest Service, clearly show that applying Pathway or Tordon RTU in this manner does not work. There is no lateral movement of the herbicide and that leaves intact, actively-conducting tissue between the hacks. Here are a couple of other quick reminders when using herbicides:

• The girdle method is best suited for trees larger than 6 inches DBH. Remember to make sure your chainsaw cut completely encircles the trunk and joins where you started. Apply one squirt (1 ml) of the herbicide, using a garden spray bottle, for every 2 inches DBH into the cut.
• In the cut-stump treatment, remember one only needs to apply the chemical to the outer ring of wood including the cambium and inner bark.
• Foliar applications are best reserved for when one desires mass kills on large swaths of small-stature invasive plants, such as sericea lespedeza, bush honeysuckle or autumn-olive.
• For more information on removing unwanted trees from your woodland, please refer to past issues of Green Horizons (Vol. 10, Nos. 1 and 2), or contact me here at MU.