There is considerable interest in high-strength cellulose nanocrystals (CNCs) that can be used as a reinforcing phase in cellulose–plastic composites. Normally, these are produced by treatment of wood pulp, but when the treatment is carried out on wood, a very low yield of CNCs is obtained. Forest Service scientists used Raman spectroscopy to better understand the molecular details of this process. They found there is considerable disorder within the cellulose microfibrils in green wood. These disordered cellulose regions are permeable to acid and undergo acid hydrolysis, the chemical method that successfully isolates crystals from crystalline cellulose materials. The chemical and thermal treatment in kraft pulping makes cellulose microfibrils partly crystalline, reducing the disorder and forming chemically robust crystalline structures. Hydrothermal treatment of green wood accomplishes the same formation of crystalline structure and allows CNCs to be obtained without the need for pulping and bleaching.