Shoot, Needle, and Cambial Growth Phenology and Branch Tracheid Dimensions in Provenances of Lodgepole Pine

1989

S. 599-605

5 Abb., 2 Tab., 37 Lit. Ang.

Unselbständiges Werk

200039010

Shoot and needle growth phenology was studied in first-order fourth-whorl branches from seven provenances of Pinus contorta Dougl. ssp. latifolia Engelm. from British Columbia and the Yukon, growing in a provenance trial at Prince George, British Columbia. The phenology of tracheid production was followed in cross sections from the midportion of the 1st-year increment of similar branches. Tracheid diameter and wall thickness were measured at increments across the ring in sections from dormant branches. Differences among provenances in the dates of growth initiation were small or negigible, although early relative growth rates were higher in the northern provenances. The times of cesation differed greatly among provenances for needle and cambial growth, but less for shoot elongation. Duration of growth had the largest effect on final needle length and tracheid numbers. Shoot length was affected largely by rates of elongation. The northern provenances had few, narrow-diameter, relatively thin-waled tracheids. Provenances showed contrasting patterns in diameter measurements across the ring, but wall thickness displayed a more consistent trend.