Documentation and user guides for SPBLOB: a computer simulation model of the joint population dynamics for loblolly pine and the southern pine beetle

SPBLOB is a computer simulation model for the interaction between loblolly pine (Pinus taeda L.), the economically most important forest crop in the United States, and the southern pine beetle (SPB: Dendroctonus frontalis Zimm.), the major insect pest for this species. The model simulates loblolly pine stands from time of planting until harvest. It mimics day-to-day changes in SPB populations, and the associated tree mortality caused by these bark beetles. In addition, it provides yearly updates of tree mortality due to competition and of growth for the surviving trees. Chiely, the model and its simulation codes are designed to function as research tools for investigating the inluence of stand properties on SPB activities, and of the reciprocal impact of beetles on tree mortality. Model output relates to both trees and beetles. Simulations provide daily and yearly luctuations in the size, composition, and spread of beetle populations within a stand. Stand types (e.g., plantations derived from seedlings or from clonally generated materials) can be compared in terms of average total merchantable volume of timber per acre at time of harvest and/or by average proportions of surviving trees. Average stand yields in the presence of beetles can also be compared with those when beetles are absent, thus providing a basis for estimating the real cost of beetle damage in loblolly stands. In this Documentation we briely describe the model, then outline the concepts and structure upon which the SPBLOB simulation source code is based. The included User Guides specify the input information regarding a loblolly stand and its environment required to run two executable Simulation Codes - a single-stand Interactive Simulation code, in which a user can specify features they wish the simulated stand to possess, and a Multiple-Simulation code that can be used to run large numbers of independent replicates of various stand designs. These Guides also describe the extensive variety of information about simulated tree and beetle populations that can be retrieved during simulations.