Tolerance of ash, oak and beech seedlings grown within woodlands to herbicides for the control of bramble (Alice Holt)

The effect of dormant season applications of triclopyr on the growth and survival of young trees was investigated in two experiments using transplants grown for one season beneath a canopy of Corsican pine prior to treatment with varying concentrations of herbicide. In one experiment, transplants of ash, beech and oak were initially grown with or without competition from bramble. In the second experiment, birch, hazel, oak, Scots pine, Douglas fir and Japanese larch were grown without competition from bramble or other ground flora. Bramble reduced survival and growth of oak and appeared to reduce the tolerance of ash, oak and beech to herbicide applications. Although the precise effect of the herbicide differed between experiments, where adverse effects on survival and growth were found these only occurred at dose rates of 1.92 and 2.88 kg a.i. ha−1 and even at these rates some of the species used were unaffected. With the exception of oak and beech in one experiment, survival exceeded 90 per cent at the end of the first growing season after application of herbicide, regardless of dose rate. The same pattern of results was found for height and diameter increments. The work reported here indicates that where bramble is threatening to outcompete and kill young tree seedlings application of 0.96 kg a.i. ha−1 triclopyr (equivalent to 2 l ha−1 Timbrel, 480 g l−1 triclopyr; Dow AgroSciences) in water in the winter season can effectively control bramble, while leaving deeply dormant seedlings of oak, beech, ash, birch, hazel, Scots pine, Douglas fir and Japanese larch unharmed. The herbicide treatments referenced in the data are: H0: no herbicide control, water only sprayed; H1: 0.48 kg a.i. ha−1 (equivalent to a product rate of 1 l ha−1 Timbrel); H2: 0.96 kg a.i. ha−1 (equivalent to 2 l ha−1 Timbrel); H3: 1.92 kg a.i. ha−1 (equivalent to 4 l ha−1 Timbrel); H4: 2.88 kg a.i. ha−1 (equivalent to 6 l ha−1 Timbrel). See also: Willoughby, I.H., Ralph Harmer, R., Morgan, G.W., Peace, A. (2013). Triclopyr applied in the winter dormant season can give effective control of bramble (Rubus fruiticosus L. agg.) without damaging young tree seedlings or other non-target vegetation. Forestry (86): 59-69.