Characterisation of Physical and Mechanical Properties of Unthinned and Unpruned Plantation-Grown Eucalyptus nitens H.Deane & Maiden Lumber

Abstract

The use of fast-growing plantation eucalypt (i.e., pulpwood eucalypt) in the construction of high-value structural products has received special attention from the timber industry in Australia and worldwide. There is still, however, a significant lack of knowledge regarding the physical and mechanical properties of the lumber from such plantation resources as they are mainly being managed to produce woodchips. In this study, the physical and mechanical properties of lumber from a 16-year-old pulpwood Eucalyptus nitens H.Deane & Maiden resource from the northeast of Tasmania, Australia was evaluated. The tests were conducted on 318 small wood samples obtained from different logs harvested from the study site. The tested mechanical properties included bending modulus of elasticity (10,377.7 MPa) and modulus of rupture (53 MPa), shear strength parallel (5.5 MPa) and perpendicular to the grain (8.5 MPa), compressive strength parallel (42.8 MPa) and perpendicular to the grain (4.1 MPa), tensile strength perpendicular to the grain (3.4 MPa), impact bending (23.6 J/cm2), cleavage (1.6 kN) and Janka hardness (23.2 MPa). Simple linear regression models were developed using density and moisture content to predict the mechanical properties. The variations in the moisture content after conventional kiln drying within randomly selected samples in each test treatment were not high enough to significantly influence the mechanical properties. A relatively high variation in the density values was observed that showed significant correlations with the changes in the mechanical properties. The presence of knots increased the shear strength both parallel and perpendicular to the grain and significantly decreased the tensile strength of the lumber. The results of this study created a profile of material properties for the pulpwood E. nitens lumber that can be used for numerical modelling of any potential structural product from such a plantation resource.

Study of the Cutting Mechanism of Oil Tree Peony Stem

“…As a kind of perennial deciduous shrub, studies on peony stem are still very scarce, although recent research on the mechanical properties of wood materials has been relatively sufficient [7]. The planting and growth characteristics of deciduous shrub determine that the pruning and harvesting equipment are different from the general forestry machines [8].…”

Construction of Wood-Based Lamella for Increased Load on Seating Furniture

“…Laminated furniture panels-lamellae and plywood-are widely used in furniture manufacturing. Properties of lamellae and plywood used in furniture projects depend on many various factors, such as moisture content of veneers, temperature, pressure and pressing time [54][55][56][57][58]. Adhesive properties, its viscosity, thickness of adhesive layer, quality of adhesive application, mechanical properties of veneers, treatment quality or removal of small elements from the surface (saw dust) are other factors affecting the bending strength [59][60][61][62][63].…”

Non-Destructive Assessment of the Dynamic Elasticity Modulus of Eucalyptus nitens Timber Boards

“…With their results, they were able to identify which defects in the timber boards had the most significant influence on their mechanical properties. Later, the same research team extended their results to other mechanical properties, such as shear and compression strength in the parallel and perpendicular directions to the wood fiber, for small-sized specimens [ 12 ].…”