Leaders in the field of vegetation modeling cover physiological phenomena typically measured at small time and space scales; the stand dynamics of forests; large-scale models of forest dynamics; the reconstruction of forest vegetation of past climates as a way to understand current global changes; and the role of forests in the global carbon cycle. Several themes run through the book, including the need to understand how processes important at one time and space scale can be conceptualized at larger scales; the need to optimize the conceptual benefits of representing processes in detail and the attendant difficulties of estimating parameters and designing tests for elaborate models; and the need to identify the most appropriate system variables.