Height growth and total volume production models for short rotation Paulownia plantations

Paulownia is a genus of fast-growing tree species originating from China, with a long history of cultivation and use. There is interest worldwide in the establishment of Paulownia plantations to address the increasing global demand for timber and to provide carbon sequestration, contributing to climate change mitigation goals. Despite this interest, published data on the growth and yield of Paulownia is scarce, and no known growth models or tools for assessing the productivity of Paulownia exist. This study aims to develop a suite of models which can be used to assess the productivity of young Paulownia plantations. A comprehensive literature review was performed to gather all previously published data, and new data was collected to complement the existing information. Based on these records, a height growth model was developed, using an Algebraic Difference Approach (ADA), along with a model predicting total volume production from stand height, using a linear mixed-effects modelling approach. The model complex was used to predict the annual biomass production of a Paulownia plantation over a 10-year rotation, which ranged from 0.5 to 25.4 oven-dry tonnes per hectare per year (odt ha⁻¹ yr⁻¹) with an interquartile range (IQR) of 0.8–9.9 odt ha⁻¹ yr⁻¹. The data available in this study and the absence of controlled experiments did not allow for causal inference of growth factors. Future experimental work investigating the effects of site, management, and genetic factors on the growth of Paulownia would be valuable for growth optimisation and for further developing the silviculture of Paulownia.