Polymorphic site index curves for noble fir from stem analysis data

Polymorphic site index curves for noble fir from stem analysisdata were compiled from 54 plot locations. On each plot location,.,e tallest dominant noble fir was felled and sectioned. Site indexwas based on total height and age at breast height, with index age
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at 100 years. A graphical test to determine if the curves are poly-
morphic indicated that polymorphism exists.