Wood Properties of Three Lesser-Used Species of Tropical Hardwood from Ghana

Transcription

1 Wood Properties of Three Lesser-Used Species of Tropical Hardwood from Ghana Kofi Poku Graduate Research Assistant Qinglin Wu Assistant Professor Louisiana Forest Products Laboratory Louisiana State University and Agricultural Center

2 Outline Background Study objective Methodology Results Summary Next steps

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4 Research Objective Examine the variation of physical and mechanical properties in the tree stem of three lesser-used species (LUS) from Ghana

5 Methodology T 1200 cm 76 cm Bolt from top section M B 76 cm 76 cm 10 cm 130 cm Bolt from middle section Bolt from breast height Disk for juvenile/mature wood boundary

6 2.0 cm Cross-Section of Bolt Showing Method of Marking and Cutting Sample Sticks for Physical and Strength Tests Sample stick North 2.0 cm Sample stick Pith West East Sample stick South 10 cm Sample stick

7 Wood Properties Juvenile/mature wood boundary -Fiber length Specific gravity Oven dry weight/vol. X density of H 2 o Shrinkage % shrinkage = decrease in dimension x 100 original dimension

8 Wood Properties Maximum crushing strength Maximum load/cross-sectional area Modulus of elasticity Stress/strain

9 Linear Regression for Fiber Length and Growth Ring for Three LUS from Ghana (J- juvenile wood; M- mature wood) Alstonia boonei J: Y = X M: Y = X Petersianthus macrocarpus J: Y = X M: Y= X Ricinodendron heudelotti J: Y = X M: Y = X

10 Juvenile -Mature Wood Boundary for Three LUS Species Fiber Length at Boundary (mm) Ring Number at Boundary Boundary Distance from pith (cm) A. boonei P. macrocarpus R. heudelotti

11 Radial Variation of Fiber Length with Ring Number for Three LUS from Ghana Fiber length (mm) Ricinodendron heudelotti Petersianthus macrocarpus Alstonia boonei Ring number

12 Variation of Specific Gravity within Trees of R. heudelotti Specific gravity tree#1 tree#2 tree#3 tree#4 tree#5 B M T B M T B M T B M T B M T

13 Variation of Maximum Crushing Strength within Trees of R. heudelotti 5000 tree#1 tree#2 tree#3 tree#4 tree#5 Maximum crushing strength (psi) B M T B M T B M T B M T B M T

14 Variation of Modulus of Elasticity within Trees of R. heudelotti tree#1 tree#2 tree#3 tree#4 tree#5 Modulus of elasticity (x1000 psi) B M T B M T B M T B M T B M T

15 Variation of Radial Shrinkage within Trees of R. heudelotti Radial shrinkage (%) tree#1 tree#2 tree#3 tree#4 tree#5 B M T B M T B M T B M T B M T

16 Variation of Tangential Shrinkage within Trees of R. heudelotti 5 tree#1 tree#2 tree#3 tree#4 tree#5 4 Tangential shrinkage (%) B M T B M T B M T B M T B M T

17 Specific Gravity between Tree Locations for R. heudelotti (mean of 5 trees) B M T 0.28 Specific gravity

18 Maximum Crushing Strength between Tree Locations for R. heudelotti (mean of 5 trees) B M T Maximum crushing strength (psi)

19 Modulus of Elasticity between Tree Locations for R. heudelotti (mean of 5 trees) B M T 600 Modulus of elasticity (x1000 psi)

20 Radial Shrinkage between Tree Locations for R. heudelotti (mean of 5 trees) 2.30 B M T Radial shrinkage (%)

21 Tangential Shrinkage between Trees of R. heudelotti (mean of 5 trees) B M T Tangential shrinkage (%)

22 Significance Levels for Differences in Wood Properties ns = not significant * = significant at 95% probability ** = significant at 99% probability

23 Differences in Wood Properties between Locations in A. boonei (All trees within species combined; n-5 trees) Wood Properties Location Mean Difference/ Significance Specific Gravity (F = 6.93**) Maximum Crushing Strength (F = 11.00**) B/M B/T M/T B/M B/T M/T 0.02* 0.03** 0.01 ns ** ns **

24 Differences in Wood Properties between Locations in A. boonei Wood Properties Location Mean Difference/ Significance Modulus of Elasticity (F = 3.36*) B/M B/T ns 59.13* Radial Shrinkage (F = 4.39*) Tangential Shrinkage (F = 0.21 ns ) M/T B/M B/T M/T B/M B/T M/T ns 0.04 ns 0.22* 0.22* 0.04 ns 0.07 ns 0.07 ns

25 Differences in Wood Properties between Locations in P. macrocarpus (All trees within species combined; n-3 trees) Wood Properties Location Mean Difference/ Significance Specific Gravity (F = 21.43**) B/M B/T 0.07** 0.03** Maximum Crushing strength (F = 24.07**) M/T B/M B/T M/T 0.41** 2127** 1049** 1078**

26 Differences in Wood Properties between Locations in P. macrocarpus Wood Properties Location Mean Difference/ Significance Modulus of Elasticity (F = 16.23**) B/M B/T 0.07** 0.03** Radial Shrinkage (F = 81.83**) Tangential Shrinkage (F = 11.09**) M/T B/M B/T M/T B/M B/T M/T 0.04** 1.04** 1.34** 0.29* 1.50* 0.81* 0.69 ns

27 Differences in Wood Properties between Locations in R. heudelotti (All trees within species combined; n-5 trees) Wood Properties Location Mean Difference/ Significance Specific Gravity (F = 6.96**) B/M B/T 0.01 ns 0.08 ns Maximum Crushing strength (F = 38.19**) M/T B/M B/T M/T 0.02** ** ** ns

28 Differences in Wood Properties between Locations in R. heudelotti Wood Properties Location Mean Difference/ Significance Modulus of Elasticity (F = 11.86**) B/M B/T 60.48** 75.36** Radial Shrinkage (F = 2.07 ns ) Tangential Shrinkage (F = 6.36**) M/T B/M B/T M/T B/M B/T M/T ns 0.02 ns 0.13 ns 0.15 ns 0.33** 0.06 ns 0.27*

29 Correlation of Wood Properties for R. heudelotti (n=5 trees) Wood Properties Wood Properties SP. Grav MCS MOE R. shrink T. shrink MCS r 0.546** MOE r 0.515** 0.495** R. shrink r 0.213** 0.180** ns T. shrink r 0.344** 0.384** 0.156ns ns T/R ratio R ns ns ns ** **

30 Comparison of Wood Properties of Three LUS Species Loca -tion A. boonei B M T P. macrocarpus B M T R. heudelotti B M T Sp. Grav MCS (psi) MOE X 1000 (psi) R. shrink (%) T. shrink

31 Summary There was no dominant pattern of variation of wood properties within trees of the three LUS. Wood properties at breast height, middle and top were generally significantly different from one another. Specific gravity correlated positively with strength and shrinkage properties.

32 Summary Petersianthus macrocarpus had the highest specific gravity, and shrinkage. It is suitable for rough, heavy construction and for railway sleepers. Ricinodendron heudelotti had the least specific gravity and shrinkage values. It is suitable for applications which require dimensional stability.

33 Summary Specific gravity for Alstonia boonei was in between the other two LUS. It has potential to serve as a substitute for Triplochiton scleroxylon (specific gravity 0.33), a mainstay of Ghana s exports.

34 Next Steps Further studies on more tree samples at shorter intervals along the stem Other strength properties including bending, tension, nail-holding capacity, etc Wood in service Evaluation of utilization potential, marketability and performance