Modelling the influence of stand structural, edaphic and climatic influences on juvenile Pinus radiata dynamic modulus of elasticity

Watt, Michael S.; Moore, John R.; Façon, Jean-Philippe; Downes, Geoffrey M.; Clinton, Peter W.; Coker, Graham; Davis, M. R.; Simcock, Robyn; Parfitt, R. L.; Dando, John; Mason, Euan G.; Bown, Horacio E.

doi:10.1016/j.foreco.2006.03.016

Cited by 67 publications

(54 citation statements)

References 14 publications

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“…The annual rings of the discs taken from the compartment characterised by a high NK ratio (compartment F) clearly exhibited larger latewood percentages than those from the low NK compartment (compartment L). Given that latewood has higher stiffness than earlywood (Watt et al 2006), the effect would be a higher overall stiffness of the wood, which would support our hypothesis. A more detailed study would be required to thoroughly test this hypothesis.…”

Section: Discussionsupporting

confidence: 68%

The prediction of the flexural lumber properties from standing South African-grown Pinus patula trees

et al. 2014

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Pinus patula is the most intensively planted conifer in the tropics and sub-tropics. The increased proportion of corewood that results when rotation ages of pine plantations are shortened has become a wood quality factor of growing concern worldwide. The purpose of this study was to develop empirically based models for predicting the flexural properties of the wood produced from relatively young Pinus patula trees. Models were based on the properties of standing trees and their effectiveness was evaluated at board, tree and compartment levels. Sample material was obtained 1 from 170 Pinus patula trees, 16-20 years old, established in 17 compartments on the Mpumalanga escarpment of South Africa. Multiple regression models were developed which managed to explain 68%, 60% and 95% of the variation in the dynamic modulus of elasticity (MOE) on individual boards, trees and compartments levels respectively. At compartment level, 80% of the variation in the 5 th percentile MOR value could be explained by the model. Sensitivity analyses showed that site index at base age of 10 years, acoustic time-of-flight, wood density and ring width were influential variables in the MOE models. The models indicated that tree slenderness during early growth seems to play a major role in determining the dynamic MOE and MOR of lumber. This is in agreement with Euler's buckling theory and the bending stress theory. The results from this study indicated that the MOE dyn and MOR of lumber can be accurately predicted on especially a compartment level. The predictive models developed can be used as management tools to improve operational decisions around tree breeding, silvicultural practices and rotation ages.

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Section: Discussionsupporting

confidence: 68%

The prediction of the flexural lumber properties from standing South African-grown Pinus patula trees

et al. 2014

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“…Faster radial growth rate often leads to a lower wood density in conifers, which is strongly linked to wood mechanical resistance [19][20][21]. This is especially true in plantations with shorter rotations than their natural stand counterparts due to a higher proportion of low quality juvenile wood [22].…”

Section: Introductionmentioning

confidence: 99%

Effect of Tree Spacing on Tree Level Volume Growth, Morphology, and Wood Properties in a 25-Year-Old Pinus banksiana Plantation in the Boreal Forest of Quebec

Hébert

Krause

Plourde

et al. 2016

Forests

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Abstract:The number of planted trees per hectare influences individual volume growth, which in turn can affect wood properties. The objective of this study was to assess the effect of six different plantation spacings of jack pine (Pinus banksiana Lamb.) 25 years following planting on tree growth, morphology, and wood properties. Stem analyses were performed to calculate annual and cumulative diameter, height, and volume growth. For morphological and wood property measurements several parameters were analyzed: diameter of the largest branch, live crown ratio, wood density, and the moduli of elasticity and rupture on small clear samples. The highest volume growth for individual trees was obtained in the 1111 trees/ha plantation, while the lowest was in the 4444 trees/ha plantation. Wood density and the moduli of elasticity and rupture did not change significantly between the six plantation spacings, but the largest branch diameter was significantly higher in the 1111 trees/ha (3.26 cm mean diameter) compared with the 4444 trees/ha spacing (2.03 cm mean diameter). Based on this study, a wide range of spacing induced little negative effect on the measured wood properties, except for the size of knots. Increasing the initial spacing of jack pine plantations appears to be a good choice if producing large, fast-growing stems is the primary goal, but lumber mechanical and visual properties could be decreased due to the larger branch diameter.

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“…5,22 However, since the mechanical properties are determined by the micro fibril angle (MFA) of the S2 cell wall layer as well as density, 23 the data from the few studies measuring the mechanical effects of hydraulic adaptation have not found consistent effects. 24,25 In these studies, complex natural systems were investigated making it difficult to distinguish between various climatic effects. We therefore grew seedlings from the three tree species Ochroma lagopus, Acacia karroo and Betula pendula under well-watered and droughted conditions, respectively, and measured the effect on the modulus of elasticity, the yield stress and the density (unpublished results).…”

mentioning

confidence: 99%

“…For instance, mechanical strengthening due to hydraulic adaptations could reduce hydraulic effects of mechanical stresses; trees growing in climates with winter frost may be stronger due to larger amounts of sap-or heart wood and drought adaptation may result in a stiffer and stronger plant. 21,24,27 This could explain why the relatively clear trade-off All tissue sections are imaged at the same magnification; the width of each image is 4, 6 mm. In O. asbeckii, where the main rigid element resisting overturning is provided by the taproot and the lower bole, the trunk has smaller and fewer vessels than either of the root sections, as often described in litterature.…”

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confidence: 99%

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Interrelations between hydraulic and mechanical stress adaptations in woody plants

Christensen-Dalsgaard

Ennos

Fournier

2008

Plant Signaling & Behavior

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in the form of positive interactions and trade-offs. In the former case, adaptations with respect to one of the two stresses positively affect the plants ability to withstand the other. Drought adaptation, for instance, is associated with an increase in the density of the tissue, which may result in stiffer and stronger wood. 5,6 Further, increasing the transectional area of the sapwood increases the conductivity as well as the rigidity of the plant and may occur as an adaptation to either drought-or mechanical stress. 7,8 In such cases, because of the importance of hydraulic sufficiency as well as adequate mechanical support, biomass must be partitioned to allow for both functions simultaneously even if this results in a surplus allocation with respect to one. In the case of trade-offs, the hydraulic or mechanical adaptations are detrimental to the plants' capabilities with respect to the other. Within the woody tissue, for instance, larger and more numerous vessels increase the conductivity but may weaken the wood. 1-3,9-11 Analogously, hydraulic optimisation dictates an increase in the transectional sapwood area up though the plant, so that the summed area of all branches at a given height would be greater than that of the trunk 12 but mechanical optimisation a decrease. 13 In the case of physiological parameters within which there are trade-offs, achieving adequate design whilst minimising biomass allocation becomes complex, 4 and a number of possible but less optimal solutions exist.In our study, 14 we looked at how mechanical as well as hydraulic parameters changed along the lateral roots of two tropical tree species, Tachigali melinonii and Xylopia nitida, both of which produce buttress roots. Along the roots of these species there is a strong distal decrease in the magnitude of the locally supported mechanical loads, 15 making them ideal model organisms for investigating mechanical adaptation of the tissue and the impact this has on hydraulic parameters. We measured the density, conductivity, strength, stiffness, sapwood area and second moment of area at various points distally along the roots as well as in the lower trunk, and compared the values to those for strain. In both species, the strength and stiffness of the tissue decreased distally along the roots as the strain dropped, and the conductivity concurrently increased exponentially (Fig. 1). This appeared related to changes in the density of the wood; in both species, the density increased towards the bole and was positively correlated with mechanical properties but negatively with conductivity. As in previous studies, the distal most The fields of plant water relations and plant biomechanics have traditionally been studied separately even though often the same tissues are responsible for water transport and mechanical support. There is now increasing evidence that hydraulic and mechanical adaptations may influence one another. We studied the changes in the hydraulic and mechanical properties of the wood along lateral roots of two species of buttr...

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Modelling the influence of stand structural, edaphic and climatic influences on juvenile Pinus radiata dynamic modulus of elasticity

Cited by 67 publications

References 14 publications

The prediction of the flexural lumber properties from standing South African-grown Pinus patula trees

The prediction of the flexural lumber properties from standing South African-grown Pinus patula trees

Effect of Tree Spacing on Tree Level Volume Growth, Morphology, and Wood Properties in a 25-Year-Old Pinus banksiana Plantation in the Boreal Forest of Quebec

Interrelations between hydraulic and mechanical stress adaptations in woody plants

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