The resiliency of forest sites after a pulse disturbance is one of the key questions mandated by the National Forest Management Act (NFMA) of 1976. This Act mandated that we maintain the productive capacity of federally managed stands. The original USDA Forest Service soil quality standards were based largely on professional judgment. The North American Long-Term Soil Productivity (LTSP) study was founded to provide a scientific basis for validating or proposing changes to the current standards. Research on the100 field installations centers around how two key properties, site organic matter and soil porosity, affect a forest’s long-term productivity capacity. Results from these installations are listed in a bibliography.