MATURATION IN DOUGLAS-FIR .2. MATURATION CHARACTERISTICS OF GENETICALLY MATCHED DOUGLAS-FIR SEEDLINGS, ROOTED CUTTINGS AND TISSUE-CULTURE PLANTLETS DURING AND AFTER 5 YEARS OF FIELD GROWTH

Seedlings, rooted cuttings from juvenile stock plants, and cotyledon-d erived tissue culture plantlets were propagated from several coastal D ouglas-fir (Pseudotsuga menziesii (Mirb.) Franco) full-sib families so that the rooted cuttings and plantlets were clonally identical. The s tock types (seedlings, rooted cuttings and plantlets) were planted in the field in spring 1987. In fall 1991, after five complete growing se asons, the plants were measured and these values compared to maturatio n ''markers'' identified for Douglas-fir in the companion paper (Ritch ie and Keeley 1994). Nodal branch lengths and nodal branch diameters d ecreased in the order seedlings > rooted cuttings > plantlets. The dec reases were about 21% for nodal branch lengths and 24% for nodal branc h diameters. Seedlings carried significantly more total branches (noda l + internodal) than the other two stock types. Height growth was simi lar for the three stock types, but plantlet height increment was begin ning to decrease during the fourth year. We conclude that vegetative p ropagules of Douglas-fir exhibited traits of mature trees. These were particularly marked in the cotyledon-derived plantlets.