Q: I have several acres of fallow farm land that I am trying to keep as an open meadow. It is a constant battle to keep the sweetgum trees out. We have mowed them down twice a year for several years, but they keep coming back from the roots and stumps. Short of bulldozing the whole place is there any way to get rid of them?
A: You are fighting the “War of Natural Succession” in the meadow. As far as Nature is concerned, an open meadow is not natural. Nature loves diversity and a monoculture of grass is an open invitation for diversification. Pine, sweetgum and maple seeds are easily distributed by wind and animals. They sprout readily, populating the meadow with potential food for small mammals. If trees were originally in your meadow, Nature is fighting, via sprouts, to re-establish diversity.
If you are convinced you have to have an open meadow, twice-yearly mowings should be sufficient. Schedule the mowings in May and July to cut off food production to the roots. Follow the mowing immediately with a spray of glyphosate (Roundup, etc) on the cut stumps to permanently keep them from re-sprouting.