Biomass and Gasification Properties of Young Catalpa Trees

Wayne A. Geyer, Walter P. Walawender


Studies were conducted to establish baseline information for use in characterizing catalpa (Catalpa speciosa) as an energy or fiber feedstock. Characteristics of whole-tree chips and wood from 7-year-old trees were similar to those of soft hardwoods: the calorific value was 18.4 kJ/g (4,401 cal/g); the fiber length was relatively short (0.63 mm); the ash content was 0.38%; and the individual whole-tree chip specific gravity was 0.39. Specific gravity values for the wood only were 0.42 at the tree base, 0.40 at DBH, and 0.38 for middle level-branch wood (all based on green volume). Air-blown gasification of whole-tree catalpa chips in a downdraft gasifier produced a low energy gas (4.8-5.2 MJ/m3). Trials at dry-chip feed rates of 95 and 123 kg/h resulted in an average gas-to-feed mass ratio of 2.6 and average char yield of 2.5% of the dry wood fed. Annual oven-dry biomass yield at an upland site in eastern Kansas was 1.9 t/ha for an operational-sized plantation (1/2 ha) with a stocking density of 2,980 trees/ha.


Catalpa;Catalpa speciosa;wood energy;specific gravity;calorific value;fiber length;gasification;biomass yield

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