Street lamp light does not delay autumnal leaf colouration of Betula pendula

Developing leaves of several mature Betula pendula trees planted for landscaping turned red when a sudden cold period occurred during the high light conditions of Spring. At the same time the leaves of other trees remained green. The effect of street lamp light on leaf colouration of the B. pendula trees with Springtime red- and green-emerging leaves was studied in the cool Autumn weather. The result suggests that the chlorophyll a and b, and carotenoid degradation of B. pendula leaves was not delayed by the street lamp light. The intensity of light and the amount of red and far-red light of the white lamp light was obviously very low to delay autumnal leaf colouration of B. pendula.