A Local Scots Pine Volume Equation from Felled Stems in Drymos Forest, Greece

Local stem-volume estimates require both suitable measurements and evidence of predictive accuracy. We developed a local equation and field table for Scots pine (Pinus sylvestris L.) in naturally established, monospecific groups in Drymos Forest, Greece. The sample comprised 60 measured stems from 59 trees, including two stems of one forked tree. Diameter at breast height (DBH) ranged from 11 to 48 cm, and standing height ranged from 6 to 25.5 m. Over-bark sectional reference volumes included an approximated stump and tip. Five equations were compared by cross-validation. The selected diameter–height equation had root mean squared error (RMSE) of 0.0905 m3, 39.29% lower than the diameter-only model. Keeping stems with shared coordinates together during validation gave similar errors. The 2014 regional equation had RMSE of 0.1000 m3, but the resampling comparison did not establish superior accuracy for the new equation. Pressler estimates with a basal cylinder had RMSE of 0.1083 m3 in this sample. The field table provides local mean-volume estimates, accompanied by an assessment of prediction uncertainty and defined limits on DBH–height combinations. Its use is conditional on comparable Drymos conditions and matching measurement conventions; performance in other forests remains untested.