Screening hydrolyzed casein as a deer repellent for reforestation applications

Abstract

Three independent experiments were conducted to evaluate hydrolyzed casein deer repellent to minimize browse damage in reforestation efforts. In the first experiment, western redcedar seedlings were treated with 12% hydrolyzed casein and a latex sticker or one of two commercial deer repellents in the nursery prior to a 45-day cold storage period. Treated and control (sticker only) seedlings were then offered to captive deer, and browse activity was monitored for 20 days. Whereas all control trees were severely browsed by day 4, the three repellents offered browse protection (17 to 33% survivability at day 20). The second experiment was a field evaluation of 12% hydrolyzed casein, a commercial repellent, and a control. Western redcedar seedlings in nine reforested units were treated and monitored periodically for browse damage by free-ranging deer. After 17 weeks, browse damage to the repellent-treated seedlings (93 and 89% survivability) was significantly lower than the control trees (85%). In the final experiment, three different products were used to affix hydrolyzed casein powder to western redcedar seedlings prior to a 45-day cold storage period. Treated seedlings were offered to captive deer, and browse activity was monitored for 28 days. Hydrolyzed casein-treated seedlings sustained significantly less browse damage (more than 70% survivability at 28 days) versus the controls (all trees browsed by day 28). Nursery treatment with hydrolyzed casein may provide significant protection for conifer seedlings in reforestation operations. Copyright © 2008 by the Society of American Foresters.