Assessment of xylem anatomical and chemical characteristics in Borehole tapped Pinus roxburghii wood: effect of diameter class and sampling height

Despite the widespread distribution and utilization of Pinus roxburghii in India, information on the intraspecific variation in anatomical and chemical characteristics of the species is limited. This study attempted to fill the gap by providing a comprehensive assessment of the anatomical and chemical characteristics of Pinus roxburghii wood. Three diameter classes (30–40 cm, 40–50 cm and 50–60 cm) and three tapping heights (50 cm, 100 cm and 150 cm) were selected to study their influence on wood properties after borehole tapping. Anatomical and chemical characteristics of wood were analyzed, and principal component analysis was applied to assess variation and relationships among variables. Significant variation (p < 0.05) among diameter classes and tapping height was observed. The number of resin ducts decreased while their diameter increased with tree diameter. The highest number of resin ducts (0.908 mm−2; 30–40 cm) and tracheid length (5.94 mm; 50–60 cm) were observed. Extractives' soluble contents increased with tree diameter, while holocellulose and lignin content varied with tree diameter and tapping height. The highest holocellulose content (68.93 %; 150 cm) and lignin content (29.33 %; 50 cm) were recorded. PCA revealed that lignin content, tracheid length, resin duct density and soluble extractives accounted for 91.00 % of total variation.