Variation in red pine (Pinusresinosa) foliar nutrient concentrations as influenced by sampling procedure

Abstract

Paired foliar samples were collected by shooting with a shotgun versus climbing and clipping near terminal foliage from twentythree 40-year-old Pinusresinosa Ait. trees located on a glacial outwash loamy sand. Samples were analyzed for N, P, K, Ca, and Mg concentrations. Regression analyses indicated that the foliar nutrient concentrations of the "shot" samples, which came from the lower crown, would be poor predictors for the foliar nutrient concentrations of the "cut' samples. Paired t-tests indicated that the shot samples consistently and significantly resulted in lower estimates of foliar concentrations of N, P, and K than did the cut samples. Shot samples were significantly higher in Ca concentrations than cut samples. The results indicate that caution is advised in the use of sampling techniques that do not result in foliar samples being collected from proven diagnostic, standardized near-terminal crown positions.