The focus of this chapter is spectroscopic and DNA analysis of cellulose materials, specifically wood products in forensic evidence. Due to the rare and sought-after nature of some materials, wood products are prone to illegal logging, mislabeling, and counterfeiting, which can be detected by forensic analysis. As a natural resource, wood products are subject to resource use laws governing over-farming and export. Many species with less desirable properties are mislabeled, used, and marketed as more expensive wood products at lower prices. Counterfeit materials jeopardize the legitimate industry, product performance, and consumer safety. Wood is a widely used building material for home and commercial units as well as furniture and is prone to counterfeiting. In other applications of botanical evidence, forensic botanists have solved crimes by analyzing tree DNA for geolocation. Counterfeits can be quickly detected and authenticated by visual analysis, microscopy, and alternate light source analysis. Instrumental analysis of trace chemicals or metals used in processing the wood product followed by statistical analysis such as PCA can confirm counterfeiting. Additionally, DNA analysis of the plant fiber can be employed for species determination to aid in solving crimes.