Comparison of leaf terpenoids and tannins in Juniperus osteosperma from woodrat (Neotoma stephensi) browsed and not-browsed trees

Neotoma lepida (woodrat) browses on the leaves of Juniperus osteosperma near Dugway, UT. A comparison between woodrat (N. lepida ) browsed and not-browsed Juniperus osteosperma trees revealed that the percentage of total volatile leaf oil yields was not significantly different between browsed trees (2.22%, 24 hr dist., DM-basis) and not-browsed trees (2.47%). On a percent total oil basis, α-pinene (4.5, 3.0%) was highly significantly higher in browsed trees, while α-campholenal (1.1, 1.3%) was significantly higher in not-browsed trees. On a mg/g DW basis, α-campholenal (0.23, 0.33%) and four compounds [p-cymene (0.34, 0.57), sabina ketone (0.20, 0.30), terpinen-4-ol (1.74, 2.67) and p-mentha1,4-dien-7-ol (0.17, 0.25)] were significantly higher in not-browsed trees. There was a trend (P=0.075) for protein-precipitable phenolics (PPP) concentrations to be lower (3.64 mg/ g) in browsed than notbrowsed (7.68 mg/ g). There was also a trend (P=0.081) for nitrogen content to be higher in browsed (0.76%) than not-browsed (0.67%). ADF (acid detergent fiber) was non-significant and averaged 27.33%. Published on-line www.phytologia.org Phytologia 98(1): 17-25 (Jan. 5, 2016).