The Use of Cyclic Balanced Incomplete Block Designs for Directional Seed Orchards

Abstract

In a recent paper (Freeman [1967]) experimental designs were described for forest tree seed orchards on sites with a constant prevailing wind. Where there is no such constant wind direction, orchards have usually been laid out in the form of polycross designs, but these are difficult both to construct and lay out. Thus new designs for non-directional seed orchards are given here. These are based on cyclic balanced incomplete block designs with four plots to a block. Designs are given for all those treatment numbers from 17 to 34 where the replication is about the same or a little larger, and the total number of trees does not greatly exceed 1000. The balanced incomplete block designs used here for 18 to 21, 24, and 31 to 34 treatments are new, though other designs for some of these treatment numbers are already known.