New Zealand Journal of Forestry (1972) 17(1): 74–80
©New Zealand Institute of Forestry
Regional variation in Douglas fir seed yeilds
G.B. Sweet and M.P. Bollman
Douglas fir cones were collected from a number of different areas in New Zealand over a four-year period, and their seed yield was assessed.
The number of full seeds per cone was generally fewer for cones from North Island than from South Island plantations, with Kaingaroa and Hawke's Bay districts having the lowest values. For Kaingaroa the data suggest that only a small percentage of the ovules in the strobilus were initially fertile, and that pollination and/or subsequent development of these ovules was restricted. In Hawke's Bay, while the percentage of fertile ovules was apparently higher, their subsequent development was still limited.
The only North Island area with particularly high seed yields per cone was Ngaumu. This area, along with most parts of the South Island, would be acceptable, on the basis of seed yield per cone, for the establishment of seed orchards of Douglas fir.