1. Anon. (1987). SAS Institute Inc. SAS/STATe Guide, vers. 6.
2. Grace, J. (1988). Temperature as a determinant of plant productivity. In:Plants and temperature. (Long, S. P. and Woodward, F. I., Eds). University of Cambridge Press, Cambridge, UK, 91–107.
3. Logan, K. T. (1965). Growth of tree seedlings as affected by light intensity. 1. White birch, yellow birch, sugar maple, and silver maple.Canadian Forest Branch, Department Publication, No. 1121.
4. Pryor, S. N. (1988). The silviculture and yield of wild cherry.Forestry Commission Bulletin 75, Forest Research Station, Farnham, Surrey, UK.