A comprehensive process model of the whole integrated forest biorefineries (IFBR) that will help analyze the overall performance including the economic and environmental factors was presented. The IFBR based on current infrastructure of pulp and paper mills involved preextraction of hemicelluloses prior to pulping (so called Value Prior to Pulping), isolation of short and long fiber after pulping, conversion of hemicelluloses and the short fiber (cellulose) to ethanol in one or more bioreactors, and the long cellulose fiber used for the production of paper and other fiber based materials such as bio-composites. The black liquor after pulping and washing containing dissolved lignin can be gasified to produce biosynthesis gas substituting for the Tomlinson recovery boiler system. The resulting biosyngas can be further synthesized to produce chemicals such as methanol, liquid transportation fuels such as DME and green diesel, etc. Electricity and process steam can also be produced from biosynthesis gas with high efficiency gas turbine. This is an abstract of a paper presented at the AIChE Annual Meeting (Salt Lake, UT 11/4-9/2007).