Applying taper function models for black locust plantations in Greek post-mining areas

Area of Science:

• Forestry Science
• Quantitative Silviculture
• Forest Mensuration

Background:

• Accurate tree volume estimation is vital for forest management and resource planning.
• Black locust (Robinia pseudoacacia, L.) plantations established on post-mining sites in Greece require volume assessment for management.
• Existing data lacks precise stem volume estimations for these significant black locust plantations.

Purpose of the Study:

• To estimate over- and under-bark stem volume for black locust plantations using taper function models.
• To identify the best-performing taper function models for predicting stem volume in this specific species and region.
• To evaluate the impact of local versus foreign model coefficients and the addition of random effects on model accuracy.

Main Methods:

• Destructive sampling of 30 black locust trees.
• Calibration and comparison of nineteen fixed-effects taper function models.
• Evaluation of model performance using root mean square error (RMSE).
• Assessment of integrated taper functions against traditional volume equations.
• Incorporation of random effects to improve model fit.

Main Results:

• Kozak's (2004) equation demonstrated the best performance for both over- and under-bark volume estimation.
• Local model fits significantly outperformed foreign model coefficients, reducing RMSE for diameter predictions.
• The addition of random effects to Kozak's equation substantially improved model fit.
• Integrated taper functions showed slightly better performance than standard volume equations for single stem volume predictions.

Conclusions:

• Taper function models, particularly Kozak's (2004) equation with random effects, provide precise stem diameter and volume predictions for black locust plantations.
• Local model calibration is essential for accurate volume estimation in specific forest stands.
• These models are valuable tools for forest inventories and sustainable management of black locust resources.