Studies of forest declines are important, because forest declines both reduce timber production and affect successional trajectories of landscapes and ecosystems. Of particular interest is decline of red pines which is characterized by expanding pockets of dead and chlorotic trees in
plantations throughout the Great Lakes Region. Here we examine the impact of two bark beetle groups, red turpentine beetles and pine engraver bark beetles, on tree mortality and the subsequent gap formation over time in a plantation. We construct spatial-temporal statistical models that quantify the relations among red turpentine beetle colonization, pine engraver bark
beetle colonization, and mortality of trees, while accounting for correlation across space and over time. For statistical inference, we adopt a Bayesian hierarchical model and devise Markov chain Monte Carlo algorithms for obtaining posterior distributions of the model parameters as well as
posterior predictive distributions.