%0 Research note
%T A non-destructive field method for measuring wood density of decaying logs
%A Mäkipää, Raisa
%A Linkosalo, Tapio
%D 2011
%J Silva Fennica
%V 45
%N 5
%R doi:10.14214/sf.91
%U https://silvafennica.fi/article/91
%X Decaying dead wood density measurements are a useful indicator for  multiple purposes, such as for estimating the amount of carbon in dead  wood and making predictions of potential diversity of dead wood  inhabiting fungi and insects. Currently, qualitative decay phases are  used as wood density estimates in many applications, since measuring the  density is laborious. A quantitative measure of density would, however,  be preferred over the qualitative one. Penetrometers, which are  commonly used for measuring the density of standing trees, might also be  applicable to dead wood density measurements. We tested the device for  making quick, quantitative measurements of decaying logs. The  penetrometer measures the depth into which a pre-loaded spring forces a  pin in the wood. We tested pins of 5 and 10 mm diameter together with an  original 2.5 mm pin and compared the results with gravimetric density  measurements of the sample logs. Our results suggest that the standard  pin works for less decayed wood, but for more decomposed wood, the  thicker 5 mm pin gave more reliable estimates when the penetration  measures were converted to densities with a linear regression function  (R<sup>2</sup> = 0.62, F = 82.9, p = 0.000). The range of wood densities successfully measured with the 5 mm pin was from 180 to 510 kg m<sup>–3</sup>.  With the 10 mm pin, the measuring resolution of denser wood was  compromised, while the improvement at the other end of density scale was  not large. As a conclusion, the penetrometer seems to be a promising  tool for quick density testing of decaying logs in field, but it needs  to be modified to use a thicker measuring pin than the standard 2.5 mm  pin.