Grading and mechanical characterization of small-diameter round chestnut (Castanea sativaMill.) timber from thinning operations

Use of non-destructive test methods on Irish hardwood standing trees and small-diameter round timber for prediction of mechanical properties

“…The main reason could be the small number of data points for each species, as only five trees were tested on each kind, when it was possible. In any case, the R 2 values obtained are not too far away from those reported by other authors using larger samples (Table 7), e.g., Vega et al (2019) obtained R 2 values from 0.64 to 0.67 when testing 216 small-diameter round sweet chestnut using a Microsecond Timer (equivalent to TreeSonic). Table 7 presents the results from other studies.…”

“…Simic et al (2019) presented far higher R 2 values and Vega et al (2019) slightly higher R 2 values when estimation was carried out from Edyn 0 than from velocity, while in the present work, slightly higher R 2 values were found using velocity than using Edyn 0 . However, Simic et al (2019) estimated mechanical properties of sawn timber while in Vega et al (2019) and the present work, small-diameter roundwood mechanical properties were estimated. It appears that for small-diameter roundwood, estimation from velocity and Edyn 0 is similar.…”

“…Most of these studies tested small-diameter round timber from thinnings, which according to Wolfe (2000) had a diameter smaller than 230 mm. On smalldiameter timber, determination coefficients (R 2 ) ranging from 0.60 to 0.75 between global MOE in bending (MOE m ) and longitudinal dynamic modulus of elasticity (Edyn 0 ) were reported by Vries and Gard (1998), Wang et al (2002), and Hermoso et al (2007), while between local MOE and Edyn 0 , they ranged from 0.49 to 0.67 (Aira et al 2019;Vega et al 2019). According to Krajnc et al (2019c), who tested three softwood species with diameters from 250 to 410 mm, the estimation of mechanical properties of sawn timber from acoustic velocities on standing trees is better in smalldiameter trees, as no correlation was found in the largerdiameter trees.…”

“…The R 2 values were dependent of the relative proportion of sapwood and heartwood, increasing with decreasing proportions of heartwood. Vega et al (2019) tested 216 small-diameter (60, 80, and 100 mm) cylindrical timber specimens of dry sweet chestnut (Castanea sativa Mill.) using a stress wave device and four-point bending tests.…”

Whole timber construction: A state of the art review

“…Starting in the 1960's and continuing to the present, governments in forested regions around the world have been increasingly faced with a major forestry challenge: an overabundance of small-diameter trees (100-250 millimetres in diameter), putting forests at increased risk of destructive high-intensity wildfires, disease, and insect attack, while suppressing the growth of trees intended for commercial harvests (Wolfe and Mosely, 2000, Scott et al, 2011, Lim et al, 2013, Bayatkashkoli and Hemmati, 2015, Fuchigami et al, 2016, Erber et al, 2016, Underhill, 2017, Vega et al, 2017, Hiroshima et al, 2018. This overstocking is caused largely by insufficient prescribed low-intensity burning in fire-prone forests, and insufficient early harvests ("thinnings") in planted forests.…”