New Zealand Journal of Forestry (1973) 18(1): 133–140
©New Zealand Institute of Forestry
The significance of forks and multileaders in nursery stock of Pinus radiata.
R. D. Burdon and M. H. Bannister
Forking and multileadering of nursery stock of Pinus radiata often appear to occur spontaneously, generally through apical abortion, but sometimes through bifurcation. The frequency and subsequent effects of these growth anomalies, mainly as they occurred in the first two years after planting, were studied. They are essentially features of the unstable juvenile growth phase in this species, rather than being subject to close genetic control. Persistent malformation resulted infrequently (1 to 2%) from apical abortion, but more frequently among bifurcations (10 to 15%), particularly when they occurred near ground level. Among populations, the frequency of apical abortion could not be related to the subsequent standard of stem form. In general, it appears that forking and multileadering in the nursery cause little malformation and do not reflect genetic quality, in the individual or in the seedlot. Therefore, it is not recommended that affected seedlings should be culled, except in extreme cases.