Estimating the yield potential of short-rotation willow in Canada using the 3PG model

Abstract

The ability to predict short-rotation coppice (SRC) willow productivity for a given region would be very helpful for large-scale deployment of this crop. The objectives of this study were to calibrate and validate the 3PG model for two commonly used clones (SX64 and SX67) and to provide yield potential estimates for 16 sites across Canada. One dataset for each clone, including leaf area index (LAI) and stem biomass, was used for calibrating parameters controlling leaf and stem growth. All other datasets, coming from eight different willow plantations, were used for model validation. Model performance was good in predicting stem biomass for the SX64 (normalized mean error (NME) = –8%, normalized root mean square error (NRMSE) = 22%) and SX67 (NME = –3%, NRMSE = 16%) clones. Predictions were more scattered for LAI, with NRMSE close to 35% and 33% and NME of 1% and 8% for SX64 and SX67, respectively. The simulation results show that the greatest yields were obtained with the three-year rotation for the SX67 clone, whereas a two-year rotation seemed to be more appropriate for the SX64 clone. The simulation results also show that growing degree-days had a significant impact on yield potential, which varied from 10.5 to 16.5 t DM·ha−1 for SX64 and from 7.5 to 11.5 t DM·ha−1 for SX67.

Multi-purpose forest management in the tropics: Incorporating values of carbon, biodiversity and timber in managing Tectona grandis (teak) plantations in Costa Rica

“…3PG growth predictions were in line with empirical simulation results (Bermejo et al, 2004;Pérez, 2008;Pérez and Kanninen, 2005), partly because Pérez and Kanninen (2005) was used for reference in the calibration. NRMSE varied considerably, but was on average about 11%, which is similar to deviations observed in 3PG calibration for other species (Amichev et al, 2016;Augustynczik et al, 2017;Jégo et al, 2017). Since teak is well studied, many parameter values could be obtained from physiological experiments previously published (see Appendix A).…”

Production and Regression Models for Biomass and Carbon Captured in Gmelina arborea Roxb. Trees in Short Rotation Coppice Plantations in Costa Rica

“…), and eucalyptus (Eucalyptus sp. ), which are species also used in SRC systems in other regions of the world [39,[41][42][43]. However, the mortality values in Location-2 were greater than the above species, reflecting again the low quality of Location-2 for the development of SRC systems with G. arborea.…”

A semi‐commercial case study of willow biomass production in the northeastern United States

“…Recently, these estimates have been reviewed and adjusted upward by Langholtz et al (2019) to yields between 9.5 and 22.5 Mg ha −1 yr −1 . The willow yield estimates presented above were based on small intensively managed experimental sites (Daly et al, 2018;Wang et al, 2015;Langholtz et al 2019) or individual plant biomass gain estimates (Jégo et al, 2017), but only the Billion-Ton Report corrected for plot size effects. The difference between yield estimates obtained from experimental plots and commercial farms has been documented in two studies.…”

“…The bioenergy modeling platform BioCro predicts yields from 8 to 20 Mg ha −1 yr −1 for the northeastern United States and of 10–20 Mg ha −1 yr −1 for Pennsylvania (Wang et al., 2015). Predictions with the 3PG model in Canada for London and Trenton, ON, and St‐Hubert, QC, estimate yields at 10–17 Mg ha −1 yr −1 (Jégo et al., 2017). The U.S. Department of Energy Billion–Ton Report (2016) Langholtz et al (2019) projects a willow yield of 8–16 Mg ha −1 yr −1 for the northeastern United States.…”