Abstract

Pinus pinaster Ait. forests have potential for resin tapping, a forestry activity that complements timber production and may increase the profitability of maritime pine stands. However, the viability of this co-production remains uncertain due to the potential effects of resin tapping on wood characteristics. The present study aimed to investigate the effects of resin tapping on the wood characteristics of maritime pine, in order to infer possible changes in wood quality, its utilisation, and, consequently, its value. The study was based on samples collected in Tresminas from resin-tapped trees (37.2 ± 6.0 years old and mean height of 15.8 ± 1.4 m) subjected to the traditional Portuguese resin tapping method for four consecutive years, and from non-resin-tapped trees (37.5 ± 8.9 years old and mean height of 14.1 ± 2.2 m). Samples were collected from different positions along the stem of resin-tapped trees (incision side, opposite side, and 50 cm above the last tapping incision) and compared with samples obtained from non-resin-tapped trees. Wood density, modulus of elasticity (MOE), modulus of rupture (MOR), extractives content, growth ring width and the number and area of resin ducts were evaluated. The effects of resin tapping on wood properties were assessed by comparing resin-tapped and non-resin-tapped trees, as well as different sampling positions within resin-tapped trees, using linear mixed-effects models. Mean comparisons were performed using Tukey’s test at a 95% significance level. No significant effects of resin tapping were observed on MOE or MOR between resin-tapped and non-resin-tapped trees. Wood from the incision side showed higher density (0.596 g·cm−3) and higher extractives content (7.49%). Resin-tapped trees produced a greater number of resin ducts after tapping; however, their area did not change. No significant differences were found in growth ring width between resin-tapped (1.75 mm) and non-resin-tapped trees (1.80 mm), although resin-tapped trees presented slightly narrower rings on average. Resin tapping in P. pinaster did not promote relevant changes in wood properties that would compromise its mechanical and physical performance. Although some alterations were detected, these were predominantly localised and restricted to the region adjacent to the tapping incision.

IPC Classification

Keywords