The effect of growth rate on the strength properties of sawn beams of silver birch (Betula pendula Roth)

R A Dunham, A D Cameron, J A Petty

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

A study was carried out into the effects of growth rate of silver birch (Betula pendula Roth) on strength properties of sawn wood beams. Despite the large variation in growth rate, with average ring width ranging from <2 mm to >4 mm, density of beams from the slowest-grown trees was only about 10% greater than that of the fastest. While density was significantly correlated with hardness (r(2) = 0.45), the small and non-significant differences in density found in beams from the slowest-to the fastest-growing trees are unlikely to have any economically deleterious effects on hardness, for example for the purpose of flooring. The high modulus of rupture (MOR) of the birch beams, with average values ranging from 47 to 63, N mm(-2), highlights the suitability of birch for load-bearing structures even though beams from fast-grown trees were significantly weaker than those from trees grown less quickly. The lower 5% quantile values, which represent the reliable timber strength and are more important than average strength, show that beams from the fastest-growing trees have a safe strength only 55% of that of beams from the slowest-growing trees and this was linked to a higher knot area ratio and sloping grain. Clear wood strength of the fast-grown trees, however, was only approximately 10% lower than that for slower-growing trees, possibly reflecting differences in the proportion and cell anotomy of juvenile wood. Beams from fast-growing birch trees are capable of being used for structural purposes. Strength, however, could be improved if silvicultural practices, such as pruning or appropriate early spacing, were adopted to reduced knot size.

Original languageEnglish
Pages (from-to)18-26
Number of pages9
JournalScandinavian Journal of Forest Research
Volume14
Publication statusPublished - 1999

Keywords

  • Betula pendula
  • growth rate
  • modulus of rupture
  • timber strength
  • TO-ROW DISTANCE
  • MECHANICAL-PROPERTIES
  • WOOD QUALITY
  • TIMBER

Cite this

The effect of growth rate on the strength properties of sawn beams of silver birch (Betula pendula Roth). / Dunham, R A ; Cameron, A D ; Petty, J A .

In: Scandinavian Journal of Forest Research, Vol. 14, 1999, p. 18-26.

Research output: Contribution to journalArticle

@article{8dec948a0d16442c8e3c85c36a8c9319,
title = "The effect of growth rate on the strength properties of sawn beams of silver birch (Betula pendula Roth)",
abstract = "A study was carried out into the effects of growth rate of silver birch (Betula pendula Roth) on strength properties of sawn wood beams. Despite the large variation in growth rate, with average ring width ranging from <2 mm to >4 mm, density of beams from the slowest-grown trees was only about 10{\%} greater than that of the fastest. While density was significantly correlated with hardness (r(2) = 0.45), the small and non-significant differences in density found in beams from the slowest-to the fastest-growing trees are unlikely to have any economically deleterious effects on hardness, for example for the purpose of flooring. The high modulus of rupture (MOR) of the birch beams, with average values ranging from 47 to 63, N mm(-2), highlights the suitability of birch for load-bearing structures even though beams from fast-grown trees were significantly weaker than those from trees grown less quickly. The lower 5{\%} quantile values, which represent the reliable timber strength and are more important than average strength, show that beams from the fastest-growing trees have a safe strength only 55{\%} of that of beams from the slowest-growing trees and this was linked to a higher knot area ratio and sloping grain. Clear wood strength of the fast-grown trees, however, was only approximately 10{\%} lower than that for slower-growing trees, possibly reflecting differences in the proportion and cell anotomy of juvenile wood. Beams from fast-growing birch trees are capable of being used for structural purposes. Strength, however, could be improved if silvicultural practices, such as pruning or appropriate early spacing, were adopted to reduced knot size.",
keywords = "Betula pendula, growth rate, modulus of rupture, timber strength, TO-ROW DISTANCE, MECHANICAL-PROPERTIES, WOOD QUALITY, TIMBER",
author = "Dunham, {R A} and Cameron, {A D} and Petty, {J A}",
year = "1999",
language = "English",
volume = "14",
pages = "18--26",
journal = "Scandinavian Journal of Forest Research",
issn = "0282-7581",
publisher = "Taylor and Francis AS",

}

TY - JOUR

T1 - The effect of growth rate on the strength properties of sawn beams of silver birch (Betula pendula Roth)

AU - Dunham, R A

AU - Cameron, A D

AU - Petty, J A

PY - 1999

Y1 - 1999

N2 - A study was carried out into the effects of growth rate of silver birch (Betula pendula Roth) on strength properties of sawn wood beams. Despite the large variation in growth rate, with average ring width ranging from <2 mm to >4 mm, density of beams from the slowest-grown trees was only about 10% greater than that of the fastest. While density was significantly correlated with hardness (r(2) = 0.45), the small and non-significant differences in density found in beams from the slowest-to the fastest-growing trees are unlikely to have any economically deleterious effects on hardness, for example for the purpose of flooring. The high modulus of rupture (MOR) of the birch beams, with average values ranging from 47 to 63, N mm(-2), highlights the suitability of birch for load-bearing structures even though beams from fast-grown trees were significantly weaker than those from trees grown less quickly. The lower 5% quantile values, which represent the reliable timber strength and are more important than average strength, show that beams from the fastest-growing trees have a safe strength only 55% of that of beams from the slowest-growing trees and this was linked to a higher knot area ratio and sloping grain. Clear wood strength of the fast-grown trees, however, was only approximately 10% lower than that for slower-growing trees, possibly reflecting differences in the proportion and cell anotomy of juvenile wood. Beams from fast-growing birch trees are capable of being used for structural purposes. Strength, however, could be improved if silvicultural practices, such as pruning or appropriate early spacing, were adopted to reduced knot size.

AB - A study was carried out into the effects of growth rate of silver birch (Betula pendula Roth) on strength properties of sawn wood beams. Despite the large variation in growth rate, with average ring width ranging from <2 mm to >4 mm, density of beams from the slowest-grown trees was only about 10% greater than that of the fastest. While density was significantly correlated with hardness (r(2) = 0.45), the small and non-significant differences in density found in beams from the slowest-to the fastest-growing trees are unlikely to have any economically deleterious effects on hardness, for example for the purpose of flooring. The high modulus of rupture (MOR) of the birch beams, with average values ranging from 47 to 63, N mm(-2), highlights the suitability of birch for load-bearing structures even though beams from fast-grown trees were significantly weaker than those from trees grown less quickly. The lower 5% quantile values, which represent the reliable timber strength and are more important than average strength, show that beams from the fastest-growing trees have a safe strength only 55% of that of beams from the slowest-growing trees and this was linked to a higher knot area ratio and sloping grain. Clear wood strength of the fast-grown trees, however, was only approximately 10% lower than that for slower-growing trees, possibly reflecting differences in the proportion and cell anotomy of juvenile wood. Beams from fast-growing birch trees are capable of being used for structural purposes. Strength, however, could be improved if silvicultural practices, such as pruning or appropriate early spacing, were adopted to reduced knot size.

KW - Betula pendula

KW - growth rate

KW - modulus of rupture

KW - timber strength

KW - TO-ROW DISTANCE

KW - MECHANICAL-PROPERTIES

KW - WOOD QUALITY

KW - TIMBER

M3 - Article

VL - 14

SP - 18

EP - 26

JO - Scandinavian Journal of Forest Research

JF - Scandinavian Journal of Forest Research

SN - 0282-7581

ER -