Estimating bark volumes for 16 native tree species on the Sierra Madre Occidental, Mexico

Updating Bark Proportions for the Estimation of Tropical Timber Volumes by Indigenous Community-Based Forest Enterprises in Quintana Roo, Mexico

“…The updated PBV of S. macrophylla (0.1370) was also slightly below the current value of 0.14. A more dramatic change was expected for mahogany, given that sizes of individuals have been significantly reduced over time [26], and larger PBVs would be expected for logs derived from smaller individuals [30]. However, the calculated PBV was very close to the value that has been used for more than 30 years.…”

“…For L. latisiliquum, M. brownei, and S. cubensis, we observed a decrease in PBV with increasing log size (D b ) (Figure 3), i.e., larger logs had a lower proportion of bark. As was suggested by Wehenkel et al [30] in a similar situation, when calculating the wood volume in these species, we would recommend setting the lower bound of the 95% confidence interval of the PBV for the largest individuals, the mean PBV for medium-sized individuals, and the upper bound for the smallest trees (Table 4). Another recommendation is to examine the degree of bark damage at the point on the log at which diameter is measured when calculating wood volume.…”

“…We used the data for D b , TV, WV, BV, and PBV per bole to fit various models following Wehenkel et al [30]. First, we examined variations in PBV with log size as reflected by D b using the allometric Equation (3), where β 1 is the allometric coefficient and β 2 is the allometric exponent between PBV and D b .…”

“…First, we examined variations in PBV with log size as reflected by D b using the allometric Equation (3), where β 1 is the allometric coefficient and β 2 is the allometric exponent between PBV and D b . We fit a simple linear regression per species log 10 transforming data and checking normality and homoscedasticity assumptions [30]. Goodness of fit was assessed using the coefficient of determination (R 2 ) and the root mean square error (RMSE).…”

“…In this study, we calculated the PBV of these six species following Wehenkel et al [30] and determined bark volume through the non-destructive Meyer method [31]. We also examined the correlation between PBV and log diameter, between bark volume and total volume, and between wood volume and total volume to examine how bark amount varied with tree size and whether this change had to be taken into account in the calculations of commercialized timber volumes.…”