To study the effects of shoot removal on the branch increasing program of Kuromatsu, a series of experiments were made in the experimental nursery of Shimane University, at Matsue City in 1969.
Young shoots(Y.S.) sprang up from buds of 6-year old Kuromatsu tree were removed at interval of 5 days from May to June. The diameters, lengths and volumes of previous shoots(P.S.) on which new ones were growing were first measured, then those young ones were removed. In their place renewed shoots(R.S.) sprang up, elongated and stopped their growth in October, when their diameter, lengths, volumes and leaf lengths were measured. The results were as follows :
1. The number of Y.S. was greater on larger P.S. than on smaller P.S.
2. The number of R.S. was, on the average, the greatest when the removal had been made late in May.
3. The growth of R.S. decreased in the case of later removal of Y.S. The growth had no relation to the size of P.S. nor to the number of R.S.