Pre-planting physiological stress assessment to forecast field growth performance of jack pine and black spruce

Abstract

This study examined the possibility that pre-planting physiological assessment, after heat stressing, could be used to forecast stem volume increment after 4 years. Several stocktypes of black spruce ( Picea mariana)(Mill.) B.S.P.) and jack pine ( Pinus banksiana Lamb.) were exposed to 45–50°C of heat stress for 15–20 min in the dark, and planted on sites with or without competing vegetation controlled. Pre-plant testing involved post-stress assessment of chlorophyll fluorescence. net photosynthetic rate, and root growth potential. Pre-plant physiology appeared to be useful in forecasting and distinguishing the competitive potential of the different stocktypes. Chlorophyll fluorescence parameters such as the ratio of variable to maximal fluorescence ( Fv Fmax ) in black spruce and the difference between the maximum M and the intermediate steady-state S ( F M-S) in jack pine, measured 1 day after the stress exposure, were more closely correlated (Pearson product-moment and Spearman-rank correlation ≥0.95) than photosynthetic rate or root growth potential to stem volume increment.