1. Edi Suhaimi BAKAR, 1 Mohd. Hamami SAHRI, 1 Zaidon ASHAARI, 1 and Fauzi FEBRIANTO 2 Oil Palm Trunks a New Alternative Material for Solid Wood Products 1 Department of Forest Production Faculty of Forestry, Universiti Putra Malaysia 43400 UPM Serdang, Selangor, Malaysia 2 Department of Forest Products Technology Faculty of Forestry, Bogor Agric. University, PO. Box 168, Bogor, Indonesia

2. Introduction ●Wood supply issues:  Shortage of wood supply, especially for solid wood  Production from forest no longer sufficient to meet the demands  Finding the alternative material of wood has become a central issue  Any alternative must be sought – include agricultural residues. ●Oil palm trunks (OPT) as strategic wood alternative material:  Huge oil palm planted area By 2006: Malaysia = 4.2 million ha, Indonesia = 5.4 million ha  Replanting at 25 years old: average annual rate 4%  Produce huge amount residues (fronds, EFB, trunk)  Trunk offer the best properties comparable to the wood  About 250m 3 OPT for each replanting hectare (most under utilized)

3. Introduction ●Characteristics of matured oil palm trunks:  Consist of two main structure: -vascular bundles- thick walled cells → high density -parenchyma tissues- thin walled cells → low density, more porous and starch  Vascular bundles are scattered in parenchyma tissues as matrix, with a reduced concentration from the outer to the inner  Great density gradient between trunk’s outer part (0.4 g/cm 3 ) and center part (0.15 g/cm 3 ).  Only the trunk’s outer part can be used as solid wood (Bakar, 2000) ●Characteristics of oil palm wood (OPW):  Very low in strength  Bad in dimensional stability  Very low in durability  Poor in machining characteristic Need properties improvement

4. Objectives & Methods ●To develop suitable sawing pattern for OPT ●To enhance the properties of OPW

5. Oil palm log Objectives & Methods ●To develop suitable sawing pattern for OPT  Being monocot (the best portions of wood at the outer part) the available sawing patterns can not be used for OPT  Three sawing patterns are compared (two are modified patterns): -Live sawing (LS) -Polygon sawing (PS) -Cobweb sawing (CS)  Test materials: -12 logs from 4 oil palm trees of 25-year-old (L: 2.5 m, D: 43–55 cm) -The logs ends were paint-coated in different color  Measurements: -Lumber Recovery: Outer-lumber, Middle-lumber, Center-lumber -Sawing time: Effective time, Ineffective time, Total time -Lumber width count  occurrence of each width criteria of the outer lumber (LS)(PS) (CS)

6. Objectives & Methods ●To enhance the properties of OPW  Material -The outer lumbers OPW (0.33–0.4 g/cm 3 ), dimension (40Tx100Rx100L) mm -Mmw-PF of various concentrations  Methods  Modified Compreg -Drying: 15% -Impregnation -Concentration: 10, 15, 20 % -Period: 1, 2, 3 hrs -Compression: 120 psi -Re-drying (microwave, 1kWh) → partially cured resin -Period : 5, 7, 10, 15 min -Power output : high -Hot pressing -Temperature: 150°C -Pressing time: 30 min -Pressing ratio: 50% (45%) Drying Impregnation Re-drying Hot-pres Densification MODIFIED COMPREG

7. Results & Discussion Sawing Study ●LS provided the highest R T but the lowest R O. Two-thirds of the results were the middle- and center-lumbers that were low in quality. ●CS produced the lowest R T (50%) but the highest R O (35%). Two- thirds of resulted lumbers were the outer-lumbers that were high in quality ●PS was in between, about half of resulted lumbers were the outer lumber ●CS is the most suitable sawing pattern in term of outer lumber recovery.

8. Results & Discussion Sawing Study ●LS consumed the shortest time and CS pattern the longest in term of either the Tt or the Te. ●PS consumed about the same Te (6.7 min.) to the LS and the same Tt (46.0 min.) to the CS ●CS consumed as twice as longer Te (15.4 min.) than the LS and PS ●Both PS and CS patterns spent plenty of Ti (39 min.)  for cant adjustment. ●The LS is the most suitable sawing pattern in term of the sawing time.

9. Results & Discussion Sawing Study ●LS and CS tend to produce narrow strips which is consider low in quality, while PS pattern tend to produce wider lumber which is high in quality: Board <10cm: LS (77%), CS (88%), PS (47%) Board >20cm: CS (0pc), LS (1pc), PS (3pcs) ●The PS was the most suitable sawing pattern in term of the outer lumber width

10. Results & Discussion Sawing Study ●After considering all the parameters above, it can be concluded that the Polygon Sawing is the most suitable pattern for the sawing of OPT. (PATENT P.20001099) ●The Polygon Sawing can produce wide outer- lumbers which are high in quality, with recovery of 27%. ●Skilled operators and good carriage are needed to run the Polygon Sawing efficiently. ●Potential OPW production in Malaysia: = 4,2 millions x 4% x 250m3 x 27% = 11.34 million m 3 /year POLYGON SAWING

11. Results & Discussion Properties Enhancement Study ●Being impregnated and densified, the density of OPW increased almost 3x from 0.37 g/cm 3 to almost 1.00 g/cm 3. ●The amount of PF resin penetrated, WPG, depend on PF concentration and impregnation period. ●These result suggested that 1-2 hrs impregnation was sufficient to impregnate the mmw-PF into OPW structure. ●This is a very short period compare to impregnation of softwood that need 24 hrs even with a lmw-PF resin as reported by Furuno [3].

12. Results & Discussion Properties Enhancement Study ●Anti swelling efficiency (ASE) that indicate dimensional stability achievement of treated OPW was 30% ●There was no significant influence in increasing the solution concentration and impregnation period to the ASE value ●These suggested that short impregnation (1 hr) with low concentration mmw-PF resin (10-15%) is good enough to enhance the dimensional stability of OPW

13. Results & Discussion Properties Enhancement Study The mechanical properties of treated OPW were substantially improved ●Young’s Modulus at the compression parallel to the grain increased from 170 to 2600 MPa ………..(15x) ●Shear strength increased from 1.9 to 13 MPa ………… (7x)

14. Results & Discussion Properties Enhancement Study ●Even the mmw-PF might not penetrate into vascular bundles, it could immediately penetrate into the parenchyma tissues. ●PF penetration to parenchyma tissues improve density/strength, durability and dimensional stability of whole OPW, and reduces density gradient between the vascular bundle and parenchyma tissues. ●Reduction in the density gradient resulted in better machining characteristic. ●The method can practically solve the four OPW flaws concurrently. UNTREATED OPW TREATED OPW

15. Conclusions ●The outer-part of OPT provide the best quality wood (OPW) that can be used as solid wood after properly treated. ●Polygon sawing is the best suited pattern to saw OPT. Sawing recovery of 27% can be achieved. ●Potentially about 11 million m 3 OPW timber can be resulted in Malaysia annually. This timbers have four flaws that need to cope with before utilization. ●Modified compreg method with mmw-PF can solve all OPW flaws concurrently. ●Treated OPW timbers can be used as a new alternative material for diminishing solid wood. ●Utilization of OPW (upon treatment) may reduce our dependency on wood from the forest, and at the same time could solve the facing problem in the plantation industry.

16. References [1]Bakar, E.S., Y.S. Hadi. 2001. Indonesian J. For. Prod. & Techno. Vol. XIV (2): 24-31. [2]Ibach, R.E. 2005. Lumen Modifications, In Rowel, R.M. (Ed.), Handbook of Wood Chemistry and Wood Composites. Taylor & Francis. N.Y. [3]Furuno, T., Y. Imamura, H. Kajita. 2004. Wood Sci. Technol. 37: 349-361. [4]Bakar, E.S., P. Md. Tahir, and Mohd. H. Sahri. 2005. Internat. Sympo. on Wood Sci. and Techno. Yokohama, Nov. 27-30. [5]Rahaya, I.S. 2001. Basic Properties of Vascular Bundles and Parenchyma of Oil Palm Wood. Thesis at School of Graduate Study, Bogor Agric. Univ. (IPB), Indonesia.