Preharvest manual herbicide treatments for controlling American Beech in Central West Virginia

Abstract

Application costs and efficacy were determined for manual preharvest herbicide treatments applied to control American beech (Fagus grandifolia Ehrh.) that was interfering with the establishment and development of black cherry (Prunus serotina Ehrh.) in central West Virginia. The treatments consisted of four levels of basal area reduction using combinations of two application methods: hack-and-squirt injection with Accord (41.5%) and basal spraying with Garlon 4 (61.6% butoxyethyl ester). The treatments were applied in late Aug. 2000 and evaluated 12 months after treatment. A numerical rating system ranging from 1 to 7 (0-100% crown affected), based on a visual estimation of top kill, was used to evaluate the efficacy of each treatment. Trees receiving a rating of 5 (75% crown control) or greater were considered controlled. After 12 months, almost complete control (99%) was achieved with both application methods. Injection of ≥6.0-in. dbh beech stems also controlled 52% and 21.6% of small untreated beech understory stems in the 2-ft tall to 0.9-in. dbh and 1.0- to 5.9-in. dbh classes, respectively. Average application costs (chemical and labor) ranged from $39.28/ac for injection of 159 stems/ac ≥6 in. dbh to $80.32/acfor basal spraying 396 stems/ac in the 1.0- to 5.9-in. dbh class and $230.09/ac for basal spraying 3,743 stems/ac in the 2-ft tall to 0.9-in. dbh class. Basal spraying the numerous small 2-ft tall to 0.9-in. dbh stems dramatically increased treatment costs. Black cherry occupied 30% of total stand basal area and accounted for 91% of total stand value ($6,288.10/ac). Application costs expressed as a percentage of total stand value ranged from <1% for the injection-only treatment up to 6.5% for combination basal spray and injection treatments. The individual stem herbicide application methods described here are applicable to the steep topography and small nonindustrial ownerships found in Appalachia.