Vegetation Management Effects Growth of Leyland Cypress Grown for Christmas Trees
Abstract Leyland Cypress trees x Cupressocyparis LeyLandii (A.B. Jacks. and Dallim.) Dallim. and A.B. Jacks. ‘Haggerston Grey’ were planted in the late winter of 1993 in a tall fescue (Festuca arundinacea Schreb.) sod. Vegetation-free circles of 0 (control), 0.6, 0.9, and 1.5 m (0, 2, 3 and 5 ft) diameters were maintained from 1993 to 1994 by a combination of commercially recommended herbicides and hand-weeding. The treatments resulted in vegetation-free areas of 0, 0.3, 0.6, and 1.8 m2 (0, 3, 7, and 19 ft2). Trees were mea sured over a 2 year period to determine the influence of vegetation-free area on growth. There were no differences in trunk cross sectional area or tree volume (calculated from height and width measurements) during 1993. By the spring of 1994, both trunk cross sectional area and tree volume increased with size of vegetation-free area. The influence of vegetation-free area on tree growth was even more pronounced by the fall of 1994. These results indicate vegetation control is important in establishing Leyland Cypress for Christmas trees. The optimum vegetation-free area appears to be between 0.6 m2 and 1.8 m2 (7 and 19 ft2) during the second year of growth.