Fig. 4
(Images re-drawn from data by Saure 1963)
Nitrogen fertilisation and canker growth. Effects of zero, light or heavy weekly leaf fertilisation with nitrogen throughout the 1962 growing season on leaf and bark N content as well as growth of cankers initiated by artificial trunk infection with N. ditissima on 1 August 1962 were measured in September (leaf N), October (bark N) and late November 1962 (canker).