Near‑Infrared Diffuse Reflectance Spectra of 200 Powdered Wood Samples – Bark, Heartwood and Sapwood from Multiple Tree Species

Spectra were acquired using a Thermo Fisher Scientific NEXUS 670 FT‑NIR spectrometer over the wavenumber range 12400–4000 cm⁻¹ (1000–2500 nm) at a resolution of 8 cm⁻¹, with 32 co‑added scans per measurement to record an average spectrum.

Each powder sample was loaded loosely into the sample cup and measured five times, and the final data for each sample is the average of these five replicate measurements. Before measurement, the spectrometer was warmed up for 30 minutes, and a polytetrafluoroethylene (PTFE) standard was used for background spectrum collection. The dataset is provided as a CSV file where each row corresponds to one sample (including sample ID, species, wood part, and absorbance values at each wavenumber), suitable for chemometric modeling such as species identification, wood property prediction, and multivariate calibration.