Geographic variation in ponderosa pine leader growth

Abstract

Growth of the shoot apices of 91 trees in a 45-year-old Pinus ponderosa Laws. provenance test was measured periodically with a transit. Analysis of the measurements led to the following conclusions: (1) 19 races of ponderosa pine planted near Priest River, Idaho, showed phenological, morphological, or physiological variation in six characters: date of beginning growth in the spring, date of ending growth, total seasonal elongation, duration of growth, length of dormant terminal bud, and rapidity of growth; (2) the variation described is continuous, although it was not possible to associate an environmental gradient to the variation pattern; (3) all trees except the local Kaniksu source achieved their maximum surge of growth during the same 7-day period, May 20-27, and this response closely paralleled temperature fluctuation; (4) simple correlations among the 19 progenies between total seasonal elongation and either beginning date, relative rapidity, or duration of growth were not significant. Correlation between dormant terminal bud length and total seasonal elongation was strong. Also, bud length was positively correlated with relative rapidity which was negatively correlated with duration of growth.

Citation

Hanover, James W. 1963. Geographic variation in ponderosa pine leader growth. Forest Science. 9(1): 86-95.