A user-driven, reduced whole-stand growth model for major hybrid poplar clones in Spain

ABSTRACT Populus spp. clones and hybrids are commonly cultivated for timber production worldwide due to their fast growth and adaptability. In Spain, growth models are currently available for the Populus × euramericana clones ‘I-214' and ‘MC'. However, the input variables required for these models are not typically available to potential users. For the most widely used P. × interamericana clones ('Beaupre', ‘Raspalje' and ‘Unal') there is currently no growth model available in Spain or elsewhere in Europe. The aim of the present study was to develop a whole-stand growth model for these five clones. Data were obtained from a network of 134 plots and 265 trees scanned by Terrestrial Laser Scanning. The structure of the growth model was mediated by plot data typically available from forest owners: plantation age, number of trees of each clone and arithmetic mean tree diameter (dm). The main component of the growth model is a dm projection function, enabling dm to be projected at any time. Sensitivity analysis of the prediction accuracy of this function revealed that the proposed model provides satisfactory predictions for time intervals of between 5 and 10 years. The growth model was implemented in a web-based plot growth simulator, facilitating its use.