Evaluation of taper measurement schemes for modeling stem profiles: a case study of two conifer species

Taper models have been widely used and treated as the primary means of calculating tree volume. However, constructing taper models is challenging in practice due to the high cost and time involved in measuring stem diameters. Therefore, we designed 20 new taper measurement schemes that increase the stem diameter measurement interval (diameter above breast height) by two to five times. The taper models were evaluated by predicting stem diameter, volume, and merchantable height of two conifer species ( Pinus sylvestris var. mongolica and Larix gmelinii) in Northeastern China. Results showed that the variable-exponent taper model of Kozak (2004) performed best for both species, while diameters can be measured every 2 m above 4 m. In addition, for both species, reducing the diameter measurement required for modeling by one-third to one-half does not increase the error in predicting the entire stem profile. This study will provide additional insights for collecting taper measurement data through traditional destructive sampling.