Techniques of constructing the second generation clone-orchards of Pinus tabulaeformis

The criteria of selecting materials for the second generation orchards were determined on the basis of the study of the primary orchard of Pinus tabulaeformis .36 excellent stocks were selected by means of half-sib progeny test on 142 stocks belonging to 3 groups of materials .Furthermore , 263 plus tree were selected from 36 stocks , and their average height , breast diameter and timber volume increased by 27.2 %, 41.1 % and 125.9 % respectively , their expecting genetic gains in the average height , breast diameter and timber volume were 13.3 %, 11.7 % and 37.2 % respectively .The techniques of constructing the second generation clone-orchards were put forward .[ Ch , 12 ref .]