Test of Four Stand Growth Simulators for the Northeastern United States

Book excerpt: SILVAH, FIBER, NE-TWIGS, and OAKSIM simulators, commonly used in the northeastern United States, were evaluated by comparing predicted stand development with actual stand development records for periods ranging from 15 to 50 years. Results varied with stand parameter, forest type, projection length, and geographic area. Except in the spruce-fir forest type where FIBER stands out as the best simulator, no single simulator is clearly superior to the others for all locations within a forest type. In general, FIBER, NE-TWIGS, and SILVAH performed best in the northern hardwood (beech- birch-maple) forest type; NE-TWIGS and SILVAH performed best in the Allegheny hardwood (cherry-maple) forest type; SILVAH and OAKSIM performed best in the oak- hickory forest type; and SILVAH was most suitable in the transition hardwood (mixture of northern hardwoods and oaks) forest type. The results give growth and yield model users more information for selecting the simulator most suitable for their particular needs. The results also can be used as a diagnostic tool for growth and yield model development.