SummaryStumps of birches (Betulaspp.) and aspens (Populus tremulaL.) in thinning stands and on clear‐felled areas were injected with herbicides by a modified bolt gun. Herbicides were formed into tablets and placed in a wedge of nylon. The wedge was fixed in the stem with the tablet placed close to the cambium. The tablets dissolved inside the tree. Injection doses were one tablet per 2·5 or 5 cm stump diameter and were done about 5 cm below the cut surface of the stump. The injector worked adequately. Injected stumps of both species produced few and shorter suckers than untreated stum