2020 journal article

Matching site-suitable poplars to rotation length for optimized productivity

Forest Ecology and Management, 457, 117670.

By: S. Ghezehei  n, J. Wright, R. Zalesny *, E. Nichols n  & D. Hazel n

co-author countries: United States of America πŸ‡ΊπŸ‡Έ
author keywords: Efficient SRWC design; Populus; Rotation length; Rotation-suitable clones; Site-suitability
Source: Crossref
Added: January 8, 2020

Diversity of applications, productivity potential, broad suitability and genetic variations make Populus a valuable fast-growing genus. Our goal was to assess if clonal site-suitability varies with rotation-length. We examined survival, growth (height, diameter at breast height) and estimated stem and total-wood (stem and branches) biomass of 89 clones near Fountain, North Carolina (35Β°42β€²7.52β€³ N, 77Β°34β€²35.04β€³ W) in the coastal southeastern USA at four- and eight-year rotations. The unsuitability of some clones was evident at early age while other clones became less suitable with stand age. Specifically, most mortality occurred by year-four, yet 25% clones experienced 17 to 50% mortality at older ages. Clone β€˜379’ was the most site-suitable with 100% survival and 141.3 kg total-wood per tree (approximately 47.5 Mg haβˆ’1 yrβˆ’1). Moreover, several clones with low survival produced high per-hectare biomass. Biomass (stem and total-wood) rankings changed between four- and eight-year rotations with only three top-ten clones in year-four (β€˜379’, β€˜402’, β€˜449’) in the top-ten of year-eight and two top-ten clones in year-eight (β€˜379’, β€˜402’) also in the top-ten of year-four. Clonal productivity differences increased by 25 to 836% with age. Clones of TD (Populus trichocarpa Torr and Gray Γ— P. deltoids Barts Ex Marsh) and DD (P. deltoides Γ— P. deltoides) genotypes were affected by wood infection (Septoria musiva) indicating that selection based on disease resistance should be performed at clonal level. Hence, for productivity-focused stands, site-suitable clones should be selected by productivity first, then narrowed by survival and rotation length. Changes in the most β€˜site-suitable’ clones can be expected between longer and shorter rotations.