Several methods such as pyrolysis, torrefaction, hydrothermal carbonization (HTC) can be applied for thermochemical conversion of biomass, in order to obtain bioproducts with high added value. The hydrothermal carbonization process has the advantages of being non-toxic, environmentally friendly and mere scale-up since it is carried out in a simple closed system under mild temperature (150-280 °C) with self-generated pressure. Noteworthy that drying of feedstocks is not compulsory, thus avoids additional costs. [1] This paper focused on optimize the HTC process considering two factors with three level central composite design highlighting the effects of temperature, time and water to biomass ratio on the maximum conversion yield of Piceaabies bark wastes. To the best of our knowledge, no systematic studies have ever been done focusing on spruce bark like feedstock for hydrothermal carbonization process. Before applying the thermochemical treatment, the feedstock was subjected to proximate analysis (table 1).Table 1. Proximate analysis for spruce barkThe conversion was conducted in a stainless-steel autoclave. The reactor was charged with 5 g of spruce bark and distilled water to achieve the water to biomass ratioof 1:5 or 1:10. The autoclave was heated up at different temperatures: 200, 240 and 250 °C, and at different reaction time: 1, 2.5 and 5 h. The central composite design was successfully employed to optimize and study the individual and interactive effect process parameters on the spruce bark wastes HTC carbonization. The results showed the process parameters have significant effects on conversion yield. The HTC final products, solid charcoal and liquid phase, were collected for characterization and further innovative applications will be proposed for each.