Non-destructive wood density assessment of Scots pine (Pinus sylvestris L.) using Resistograph and Pilodyn

Abstract

We tested two methods for non-destructive assessment of wood density of Scots pine standing trees: One based on penetration depth of a steel pin (Pilodyn) and the other on micro-drilling resistance (Resistograph). As a benchmark we used wood density data from x-ray analysis (SilviScan). We assessed in total 622 trees of 175 full-sib families growing in a single progeny test. Pilodyn was applied with bark (PIL) and without bark (PIL B ). Raw Resistograph drilling profiles (RES) were adjusted (RES TB ) in order to eliminate increasing trend caused by needle friction. Individual narrow-sense heritability of benchmark SilviScan density (DEN; 0.46) was most closely approached by that of adjusted RES TB (0.43). Heritabilities were lower for unadjusted RES (0.35) as well as for PIL and PIL B (both 0.32). Additive genetic correlations of the benchmark DEN with RES, RES TB , PIL and PIL B were 0.89, 0.96, 0.59 and 0.71, respectively. Our results suggest that Resistograph is a more reliable tool than Pilodyn for wood density assessment of Scots pine; however, we highly recommend adjusting Resistograph drilling profiles prior to further analyses.