Critical height sampling: A model-free method for efficient forest volume estimation
Accurate forest volume estimation is crucial for sustainable forest management, but the most commonly used methods often rely on models that may not always be applicable across different tree species or environmental conditions. A new study in Forest Ecosystems provides a comprehensive field study of the Critical Height Sampling (CHS) method, suggesting that this approach could revolutionize how we estimate forest stand volume.
CHS doesn't rely on complex volume or taper models, instead using a "critical height" measurement that reflects the taper of the entire tree. This model-free approach eliminates potential biases from traditional methods, making it especially useful when reliable models are unavailable. Researchers from the University of British Columbia examined 65 plots in Taiwan's Xitou Forest Management District, comparing CHS with Horizontal Point Sampling (HPS), a more conventional method that uses volume models.
The study found that while CHS was less precise than HPS, it provided much more consistent volume estimates across varying Basal Area Factors (BAFs). CHS also showed efficiency advantages in terms of measurement time, requiring less time per tree than traditional methods. This consistency in results across different sampling intensities makes CHS a promising tool for forest inventory planning.
"Our study highlights the strength of CHS in providing reliable and stable volume estimates, even in forests where traditional models may not work well," said Hsiao-Chi Lo, lead author of the study. "This method could be an invaluable tool for forest managers who need an alternative to model-dependent methods."
The findings suggest that CHS could complement existing volume estimation techniques, especially in forests where reliable volume models are hard to apply. As forest management increasingly looks for ways to balance sustainability with precision, CHS offers a new path forward, combining simplicity with scientific rigor.
More information: Hsiao-Chi Lo et al, Demystifying field application of Critical Height Sampling in estimating stand volume, Forest Ecosystems (2025).
Provided by Tsinghua University Press