Genetic Variation in Some Phenological Characteristics of Forest Trees

摘要: During the night between June 9 and 10, 1972, temperature at Rhinelander dropped to — 3.5°C. Severe frost damage of new shoot growth both conifers hardwoods resulted (Plate 1). Since that dismal we have been evaluating different spruce species, populations within progencies individual parent trees populations. At all levels there are significant differences in amounts damage. Some caused by actual resistance frost; actively growing tissues can withstand freezing temperatures without showing (Kiellander, 1953, 1962), but much variation is due avoidance. Seasonal development differs among types, since phenophases differ susceptibility frost, be seen. Thus closely related time initiation growth.