Production of hybrid poplar under short-term, intensive culture in Western Colorado

An irrigated study was conducted at the Western Colorado Research Center at Fruita for 6 years to evaluate eight hybrid poplar clones under short-term, intensive culture. The eight clones included in the study were Populus nigra x P. maximowiczii (NM6), P. trichocarpa x P. deltoides (52225, OP367), and P. deltoides x P. nigra (Norway, Noreaster, Raverdaus, 14274, 14272). Data were collected for growth, aerial biomass yield, dry matter partitioning, carbon sequestration, and insect and disease infestation. OP367 and 52225 consistently had larger tree diameters than other hybrids for each of the 6 years. Averaged across clones, yield was 58.4 Mg ha−1. OP367 had the highest yield at 72.2 Mg ha−1 and 14274 had the lowest yield at 41.0 Mg ha−1. The yield of OP367 was 1.8 times greater than that of 14274. Carbon yield over the 6 years of testing was highest for OP367 at 33.4 Mg C ha−1 and lowest for 14274 at 18.8 Mg C ha−1. Of the eight clones tested, OP367 was the most adapted and productive clone in this short-term, intensive culture system in the arid environment of the Grand Valley of western Colorado as evidenced by its productive growth, yield, insect resistance, winterhardiness, and tree architecture. Several insect species infested the poplar clones over the course of the rotation. Best management practices for growers who produce hybrid poplar under short-term, intensive culture should include the following: (1) plant highly productive clones, (2) poplar clones with suitable tree architecture for production and market objectives should be used, (3) if carbon sequestration is an important production objective, plant a suitable clone, (4) some poplar clones develop chlorosis when planted in high pH soils and should be avoided, and (5) use poplar clones that have been shown to exhibit resistance to specific insect species.