Managing invasive tree stumps in the restoration of legacy chestnut orchards

The removal of tree stumps is an important component in field recultivation, park management, and land development (or restoration). Mulching the stumps to ground level is a fast and effective solution that minimizes soil disturbance and avoids the burden of rootstock disposal typically incurred when uprooting the stumps. This study reports on the productivity and cost of mulching tree stumps using a light, remote-controlled tool carrier (36 kW) equipped with a dedicated forestry mulcher. The new machine was used for grinding the stumps of invasive alder trees in a legacy chestnut orchard restored to production. Mulching proved fast and effective. The light machine ground over 60 stumps (diameter approximately 30 cm) per scheduled machine hour (SMH), treating a hectare in less than 3.5 SMH. This translated into a treatment cost of 202 € ha-1. Regression analysis yielded an equation for estimating grinding time as a function of stump volume. Using this equation and estimating the existing number of stumps per hectare, operators can easily calculate the productivity and cost of each given job.