Systematic Review of Applications of Near-Infrared Spectroscopy in Forest Engineering and Wood Industry: Progress and Perspectives

Near-infrared spectroscopy (NIRS) has been widely applied in forest engineering and the wood industry to meet demands for sustainability, green production, and precision forestry. As global focus intensifies on climate change and resource efficiency, NIRS's advantages in nondestructive testing and rapid analysis have become increasingly prominent. Based on bibliometric analysis, this review systematically examines 886 publications from the past 35 years, analyzing publication trends, critical experimental steps, research hotspots, and 11 application themes to assess NIR's development, current challenges, and future potential in this field. Our study indicates that NIRS applications for assessing wood's basic properties-such as physical, chemical, anatomical, and mechanical properties-and monitoring pulp production are relatively mature. However, its use in emerging areas like functional materials, biofuels and waste, and archaeological wood remains in an exploratory phase. Additionally, research into spectral model transferability is still in its infancy, limiting broader applications. Few studies explore NIRS's interpretive value for non-chemical and non-anatomical properties, restricting its effectiveness in complex scenarios. This review highlights advanced methods, key challenges, and future research directions, emphasizing the need to address model interpretability, universality, and integration with other analytical techniques and policy contexts, thus providing crucial insights for future decision-makers.