Millwood honeylocust trees: seedpod nutritive value and yield characteristics

Abstract

The Millwood (MW) cultivar of the honeylocust (Gleditsia triacanthos L.) tree has gained particular interest for silvopasture systems due to the production of edible, high-sugar seedpods that livestock may consume after pod drop. Two studies were conducted within an active sheep and honeylocust silvopasture to (1) estimate nutritional variability of seedpods among MW trees, and to (2) determine seedpod yields and seasonal production variation of MW trees. Seedpods were harvested from each pod-bearing MW in October 2008 and 2009, just prior to pod drop. Nutritional characteristics such as detergent fibers, crude protein, in vitro digestibility, and sugar concentrations were determined for fractionated husk and seed components. Further, MW fodder yields were estimated in 2008, 2009, and 2010 through field measurements and tree yield classification. Both ground husks and seeds were low in fiber (273 and 132 g kg⁻¹ neutral detergent fiber, respectively) and highly digestible (787 and 963 g kg⁻¹, respectively). Seed husk sugar concentrations averaged 223 g kg⁻¹. Based on the nutritive fractions assayed, whole ground MW seedpods grown in Virginia have a nutritional profile comparable to that of ground whole-ear dent corn (Zea mays L.) or oat (Avena sativa L.) grain. Nearly all MW trees displayed some form of alternate-bearing pattern. Average dry matter yields of pod-bearing trees were 15.8, 4.8, and 14.7 kg tree⁻¹ in 2008, 2009, and 2010, respectively. Pod yield and quality indicate MW honeylocust trees have good potential as fodder-bearing trees in temperate silvopasture systems.