User's guide for SYSTUM-1 (Version 2.0): A simulator of growth trends in young stands under management in California and Oregon

SYSTUM-1 is an individual-tree/distance-independent simulator developed for use in young plantations in California and southern Oregon. The program was developed to run under the DOS operating system and requires DOS 3.0 or higher running on an 8086 or higher processor. The simulator is designed to provide a link with existing PC-based simulators (CACTOS and ORGANON) currently in use in northern California and southern Oregon. The input requirements include a sample of trees including heights, species, and expansion factor as well as a sample of competing vegetation including percent cover and height for each species on a given plot. Optional input items for trees are diameter at breast height, live crown ratio, and past periodic annual increment. Preface SYSTUM-1 is the result of the first phase of the Small Tree Growth Modeling Project sponsored by the California Forest Research Association, a cooperative of public and private forest resource management agencies. This effort is funded by contributions from cooperators. The Pacific Southwest Research Station, USDA Forest Service, was responsible for analyzing the data and developing the computer simulator. Early versions of the simulator were programmed by Larry Ticknor. SYSTUM-1 is an individual-tree/distance-independent simu-lator developed for the DOS operating system. The simulator is designed to predict growth of young plantations up to an age where other simulators (e.g., CACTOS, ORGANON, Prognosis) may be used. Tree-level data input include species, diameter , height, crown ratio. Plot-level data input includes competing vegetation cover and height by species for each plot. Stand-level data input includes stand age and site index. The simulator will process the major conifer species of the mixed conifer zone. The data used for model development were primarily plantations dominated by either ponderosa pine or Douglas-fir. Data were obtained from stands throughout the northern Sierra Nevada extending northward into southwestern Oregon. The data were provided by industry cooperators, the USDA Forest Service (both Region 5 and Region 6) and the Medford District of the Bureau of Land Management. The simulator may be used to evaluate both pre-commercial thinning and treatment of non-tree vegetation. Among the thinning options are thinning from below to a target density, thinning proportionately to a target density, and thinning to a specified proportion of density across a range of diameters. The simulator also provides an option for treating competing vegetation. Among the output options is the creation of tree-list files in either ORGANON or CACTOS format. In addition, the …