Compressive strength parallel to grain of earlywood and latewood of yellow pine

Piotr Mańkowski,Agnieszka Laskowska

doi:10.4067/s0718-221x2021000100457

Piotr Mańkowski, Agnieszka Laskowska

Open Access

https://doi.org/10.4067/s0718-221x2021000100457

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Abstract

The compressive strength parallel to grain of earlywood and latewood from the yellow pine sapwood and heartwood areas was examined in the study. The structure of the basic structural elements of wood - tracheids, which conduct water and/or perform the mechanical function - was also characterized. The compressive strength parallel to grain of latewood in the sapwood area was found to be twice as high as the compressive strength parallel to grain of earlywood. The compressive strength parallel to grain of latewood in the heartwood area, on the other hand, was found to be 2,5 times higher than the compressive strength parallel to grain of earlywood. This was due to the density of particular areas of wood and the dimensions of structural elements - tracheids. In the sapwood area, the density of latewood was ca. twice as high as the density of earlywood. Similar relationships were found for heartwood. The thickness of latewood tracheids was found to be 1,5 times greater than the thickness of earlywood tracheids. These relationships were observed in sapwood and heartwood. The diameter of earlywood tracheids in radial direction was twice as large as the diameter of latewood tracheids. These relationships were observed in yellow pine sapwood and heartwood

Highlights

Yellow pine (Pinus ponderosa) is the most commonly found pine species in North America (FNA 1993)
From data available in literature it can be seen that the average density of yellow pine wood with a moisture content of 12 % - 15 % ranges from 340 kg/m3 to 500 kg/m3 (Wagenführ 2007)
The compressive strength parallel to grain (CS) of yellow pine heartwood, determined in standard size samples, was 21 % higher than in the case of sapwood. This was correlated with wood density, since the average density of yellow pine heartwood was 23 % greater than sapwood density

Summary

Introduction

Yellow pine (Pinus ponderosa) is the most commonly found pine species in North America (FNA 1993). Trees grow up to 72 m in height, while the trunk can reach up to 2,5 m in diameter. It is a species with a significant economic importance. Compressive strength parallel to grain is one of the most frequently used strength tests (Wagenführ 2007, ISO 13061-17/2017). This is largely due to the fact that most construction materials made of wood are subjected to bending and/or compression. Compressive strength parallel to grain varies significantly depending on the wood species, density, moisture content, anatomical structure, annual ring width, share of latewood, wood defects (Wagenführ 2007, Kretschmann 2010). The age of the trees from which sample material for testing is obtained is important (Listyanto 2018)

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