Sustainable development goals require a reduction in the existing heavy reliance on fossil resources. Forestry can be considered a key resource for the bioeconomy, providing timber, energy, chemicals (including fine chemicals), and various other products. Besides the main product, timber, forestry generates significant amounts of different biomass side streams. Considering the unique and highly complex chemical composition of coniferous needle/greenery biomass, biorefinery strategies can be considered as prospective possibilities to address top segments of the bio-based value pyramid, addressing coniferous biomass side streams as a source of diverse chemical substances with applications as the replacement of fossil material-based chemicals, building blocks, food, and feed and applications as fine chemicals. This study reviews biorefinery methods for coniferous tree forestry biomass side streams, exploring the production of value-added products. Additionally, it discusses the potential for developing further biorefinery strategies to obtain products with enhanced value.

In recent years, agricultural by-products have become more valued due to the growing emphasis on sustainable agriculture and circular economies. This study concentrated on sea buckthorn (Hippophae rhamnoides) by utilizing its residual leaves and twigs—traditionally discarded or composted—as a source of high-value bioactive compounds. Aqueous and alcohol extraction was applied to sea buckthorn biomass using varying cycle numbers and extraction durations. The resulting extracts were analyzed for total phenolic content (TPC), proanthocyanidins (PACs), and antioxidant activity. The findings revealed that leaf extracts tended to have higher TPC, with the peak value in Leaves extract_4 (61.22 ± 0.26 mg_GAE/g), whose extraction was performed using 60 cycles of 10 min duration. Sea buckthorn twig water extracts demonstrated higher concentrations of PACs compared to leaf extracts, with the highest value observed in Twigs extract_5 (52.79 ± 0.21 mg_CE/g) whose extraction was performed using 60 cycles of 5 min duration. The antioxidant activity assessed via DPPH revealed significant functional potential, with sea buckthorn leaf extracts (aqueous and ethanolic) showing 82–90% activity, and twig extracts 77–90%. Environmental impacts of the tested extraction scenarios, assessed using a life-cycle assessment methodology, confirmed that extraction scenarios yielding higher concentrations of bioactive compounds from the same biomass were associated with lower environmental burdens.