A Comparison of the kraft pulp properties of P.elliottiiand theP. elliottiixP. caribaeavar.hondurensishybrid grown in Queensland, Australia

Stanger, T. K.; Shaw, Matthew; Braunstein, Ron; Nikles, D. G.

doi:10.1080/10295925.1999.9631236

Cited by 6 publications

(5 citation statements)

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“…Delam GL = 100 l tot,delamGL l glueline (3) where l max,delam is the maximum delamination length; l glue line is the perimeter of one glue line in a specimen; l tot,delam is the total delamination length; l tot, glue line is the sum of the perimeters of all glue lines in the specimen; and l tot,delam GL is the total delamination in a single glue line.…”

Section: Sample Manufacture and Preparationmentioning

confidence: 99%

“…elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze) (PEE×PCH) hybrid is one such fast-growing plantation pine increasingly being grown around the world [1][2][3][4][5][6][7]. In a recent study by Cherry et al [8], it was confirmed that a majority of the sawn PEE×PCH that fell short of Australian Machine Graded Pine (MGP) standards was low-stiffness timber from the core wood zone of the tree.…”

Section: Introductionmentioning

confidence: 99%

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Maximizing the Use of Out-of-Grade Hybrid Pine in Engineered Wood Products: Bond Performance, the Effect of Resin Streaking, Knots, and Pith

Cherry,

Karunasena,

Manalo

2023

Forests

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The evolution toward small-diameter and fast-growing plantation timbers such as the Pinus elliotti var. elliottii (Engelm) × Pinus caribaea var. hondurensis (Sénéclauze) (PEE×PCH) hybrids around the world is producing large volumes of core wood that are falling short of structural sawn timber grading requirements. Engineered timber products such as cross-laminated timber (CLT) and glue-laminated (glulam) offer potential solutions to value-adding this resource, but the bond performance of this feedstock and the extent to which current standards and guides address its common characteristics for bond performance need to be understood. This study investigated the bond quality and performance of clear defect-free, low stiffness out-of-grade PEE×PCH and evaluated this performance using the pass/fail criteria of the CLT bond performance requirements of three national CLT standards. 5-layer CLT delamination samples and shear block test samples were glued using one-component polyurethane (PUR). This process was repeated for common occurring characteristics in this resource of resin, knots, and pith to understand their impact and inform an evaluation on the need to restrict their inclusion. Clear samples had an average glue line delamination of 2.9% and an average glue line wood failure of 96.7%. Resin achieved 9.3% and 92.6%, respectively. While knots had the lowest performance at 24.4% and 77.4%, respectively. When pith was at or adjacent to the glue line, wood failure occurred through the pith and its immediate surrounding fiber. Shear strength and wood failure tests were carried out on glulam and CLT-oriented samples. CLT knot samples were tested in two load orientations. Glulam-oriented samples in clear, resin, pith, and knots achieved an average shear strength of 8.5 MPa, 8.2 MPa, 7.9 MPa, and 8.2 MPa, respectively, and wood failure of 86%, 85%, 90%, and 69%, respectively. CLT-oriented samples in clear and resin both achieved average shear strengths of 4.0 MPa; 0°-loaded and 90°-loaded pith samples achieved 3.6 MPa and 2.4 MPa, while 0°-loaded and 90°-loaded knot samples achieved 4.2 MPa and 4.7 MPa respectively. Average wood failures were 90%, 89%, 96%, 96%, 83%, and 51%, respectively. PRG320 was found to be the most restrictive standard. Resin, knots, and pith were not addressed in the evaluation of delamination or shear strength in any standard, and PRG320 was the only standard to restrict these characteristics over and above structural grading rules. The amount and type of characteristics present vary considerably in structurally graded wood, and even more so for this out-of-grade resource. It was determined that the negative impact that resin, knots, and pith have on bond quality and bond performance calls for some restriction of their inclusion in order to achieve the author’s interpretation of the intended bond performance requirements of the CLT standards, which currently do not address these characteristics well or at all. A proposed modification to the PRG320 effective bond area was presented as a proactive solution.

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Section: Sample Manufacture and Preparationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Maximizing the Use of Out-of-Grade Hybrid Pine in Engineered Wood Products: Bond Performance, the Effect of Resin Streaking, Knots, and Pith

Cherry,

Karunasena,

Manalo

2023

Forests

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“…In Queensland, Australia, there are more than 90,000 ha already established [1]. As a relatively new taxa, these pines are showing promising results for growth and structural properties in Australia [2,3], Africa [2,4], China [5,6] and Central and South America [7,8]. Their high volume growth rate, good wind resistance, stem straightness and superior wood quality [3] ensure their future as a source of structural sawn timber for use in civil engineering and construction.…”

Section: Introductionmentioning

confidence: 99%

“…Nonetheless, despite the low bending MOE, some studies have found that juvenile and corewood can have some good properties and attributes including increased durability with respect to mechanical degradation, and transverse mechanical properties [18]. With the increasing supply of PEE × PCH hybrids around the world [2][3][4][5][6][7][8], there is a need to value add the low-stiffness out-of-grade component of this new material resource and look for repurposing opportunities such as engineered timber products.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Properties of Low-Stiffness Out-of-Grade Hybrid Pine—Effects of Knots, Resin and Pith

Cherry

Karunasena

Manalo

2022

Forests

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Out-of-grade pine timber is an abundant material resource that is underutilised because its mechanical properties are not well understood. Increasing trends toward shorter rotation times and fast-grown plantation pines around the world such as Pinus elliottii x P. caribaea var. hondurensis hybrid (PEExPCH) mean low-stiffness corewood is becoming a larger portion of this out-of-grade population. This study characterised the modulus and strength properties in bending, compression parallel to grain (CParG) and compression perpendicular to grain (CPerpG), shear and tension strength of low-stiffness out-of-grade PEExPCH. The effect of resin, knots and pith on these properties were also investigated. The results show that in clear wood, the MOE in bending, CParG, CPerpG and shear modulus are 6.9 GPa, 5.78 GPa, 0.27 GPa and 0.59 GPa, respectively, while strengths are 45.8 MPa, 29.4 MPa, 6.7 MPa, 5.7 MPa, respectively. The tensile strength is 32.4 MPa. Resin significantly increased density 45% higher than clear, but performed similar with the exception of CPerpG MOE and strength which were significantly different. Resin area ratio (RAR) has a moderate correlation with density with an R2 of 0.659 but low to no correlation for mechanical properties. Knots were significantly different to clear for all test types and within a range of 48% to 196%. Knots were high in CPerpG MOE and strength but lower for all other properties and had the largest negative impact on tensile strength. Knot area ratio (KAR) had low to moderate correlation with tension strength and CPerpG MOE with R2 of 0.48 and 0.35, respectively. Pith was within the range of 76% to 121% of non-pith samples for structural performance, some of which were significantly different, and pith samples were higher in density than non-pith. This new information is crucial for the effective establishment of grading rules, design optimisation and utilisation of low-stiffness out-of-grade PEExPCH as a new material resource in civil engineering applications.

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“…Although tube seedlings have been successfully cultivated from 28 Pinus species [1] including P. pinea [2] , P. roxburighii [3] , P. cembra [4], P. wallichiana [5,6] , P. heldreichii [7] , P. ayaccahuite [8] , P. thunbergii × P. massoniana [9] , P. maximartinezzii and P. pinceana [10] , only P. radiata is commercially produced [11] . Studies on P. elliottii × P. caribaea are rare and only focused on the survival and height growth [12] , wood properties [13][14][15] and the effects of temperature, moisture, illumination and other factors on cultivation of cutting seedlings [16,17] . Only one paper studied tissue culture of P. elliottii × P. caribaea [18] using its mature embryos to obtain adventitious buds in vitro.…”

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confidence: 99%

Stem Tissue Culture of Pinus elliottii × Pinus caribaea

Huang

2012

2012 International Conference on Biomedical Engineering and Biotechnology

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Using tender stems of the current-year in 5-year-old P. elliottii × P. caribaea as explants and exploiting orthogonal experiments, we optimized the growth conditions of Pinus elliottii × Pinus caribaea in vitro and successfully obtained the plantlets. We found that: (1) as explants, fragments at 1.5~3.0 cm from top to bottom of stems that cultured in DCR media supplemented with 2.0 mg/L N6-benzyladenine (6-BA), 0.10 mg/L alphanaphthyl acetic acid (NAA) and 30 g/L sucrose have the best early differentiation rate of 43.7%;(2) among the tested conditions, DCR media supplemented with 2.5 mg/L 6-BA and 0.2 mg/L NAA is most suitable for propagation of adventitious buds giving a propagation rate and fold of 96.7% and 6.2, respectively; (3) DCR media supplemented with 0.3 mg/L NAA, 1.5 g/L activated carbon and 20 g/L sucrose is best for elongation of adventitious buds giving propagation rate of 444.6%; (4) transplantation of seedlings to ½ DCR media supplemented with 2.0 mg/L NAA and cultured in dark for 10 days followed by illumination 12 h/d with 40 mol·m-2·s-1 intensity resulted as high as 55.3% rooting rate.

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A Comparison of the kraft pulp properties of P.elliottiiand theP. elliottiixP. caribaeavar.hondurensishybrid grown in Queensland, Australia

Cited by 6 publications

References 1 publication

Maximizing the Use of Out-of-Grade Hybrid Pine in Engineered Wood Products: Bond Performance, the Effect of Resin Streaking, Knots, and Pith

Maximizing the Use of Out-of-Grade Hybrid Pine in Engineered Wood Products: Bond Performance, the Effect of Resin Streaking, Knots, and Pith

Mechanical Properties of Low-Stiffness Out-of-Grade Hybrid Pine—Effects of Knots, Resin and Pith

Stem Tissue Culture of Pinus elliottii × Pinus caribaea

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A Comparison of the kraft pulp properties of P.elliottiiand theP. elliottiixP. caribaeavar.hondurensishybrid grown in Queensland, Australia

Cited by 6 publications

References 1 publication

Maximizing the Use of Out-of-Grade Hybrid Pine in Engineered Wood Products: Bond Performance, the Effect of Resin Streaking, Knots, and Pith

Maximizing the Use of Out-of-Grade Hybrid Pine in Engineered Wood Products: Bond Performance, the Effect of Resin Streaking, Knots, and Pith

Mechanical Properties of Low-Stiffness Out-of-Grade Hybrid Pine—Effects of Knots, Resin and Pith

Stem Tissue Culture of Pinus elliottii &#x0D7; Pinus caribaea

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Stem Tissue Culture of Pinus elliottii × Pinus caribaea