The chemical defense response of pines includes both terpenes and phenolic compounds. Phenolic compounds are secondary metabolites that are ubiquitous, but highly variable, among plant species. The focus of this thesis is the phenolic component of the defense mechanisms of two north American pine species, loblolly pine (Pinus taeda) and whitebark pine (P. albicaulis). Chapter 2 aims to characterize the phenolic profile of loblolly pine, which had yet to be identified, and investigate how the compounds may change after inoculation with root feeding beetle-associated blue stain fungi. I identified and quantified 25 compounds and measured their significant variation, both as increases or decreases, after induction. Chapter 3 investigates whether the phenolic composition of whitebark pine can be used to predict potentially resistant individuals to mountain pine beetle. While I found significant differences in single compound concentrations between resistant phenotypes, the overall profile was not a good predictor for resistance.