Oil Palm Trunks
a New Alternative Material for Solid Wood Products
Edi Suhaimi BAKAR,1 Mohd. Hamami SAHRI,1 Zaidon ASHAARI,1
and Fauzi FEBRIANTO2
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
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 250m3 OPT for each replanting hectare (most under utilized)
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/cm3) and center
part (0.15 g/cm3).
 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
Objectives & Methods
● To develop suitable sawing pattern for OPT
● To enhance the properties of OPW
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:
(CS)
(LS)
(PS)
- 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
Oil palm log
Objectives & Methods
● To enhance the properties of OPW
 Material
- The outer lumbers OPW (0.33–0.4 g/cm3), dimension (40Tx100Rx100L) mm
- Mmw-PF of various concentrations
 Methods  Modified Compreg
Drying
Impregnation
Re-drying
Hot-pres
Densification
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%)
Results & Discussion
Sawing Study
● LS provided the highest RT but
the lowest RO. Two-thirds of the
R-outer (RO)
R-midle (RM)
R-center (RC)
R-total (RT)
80
results were the middle- and
center-lumbers that were low in
60
quality.
40
● CS produced the lowest RT (50%)
but the highest RO (35%). Two20
thirds of resulted lumbers were
0
the outer-lumbers that were high
LS
PS
CS
in quality
Sawing patterns
● 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.
Lumber Recovery (%)
100
Results & Discussion
Sawing Study
● LS consumed the shortest time
and CS pattern the longest in
T-efective (Te)
T-inefective (Ti)
term of either the Tt or the Te.
T-total (Tt)
45
● PS consumed about the same Te
(6.7 min.) to the LS and the same
30
Tt (46.0 min.) to the CS
15
● CS consumed as twice as longer
Te (15.4 min.) than the LS and PS
0
● Both PS and CS patterns spent
LS
PS
CS
plenty of Ti (39 min.)
Sawing patterns
 for cant adjustment.
● The LS is the most suitable sawing pattern in term of the sawing time.
Sawing Time (min.)
60
Results & Discussion
Sawing Study
41
25
Width Count
20
> 20 cm
11-15 cm
< 5 cm
16-20 cm
5-10 cm
15
10
5
0
LS
PS
Sawing patterns
● 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)
CS
● The PS was the most suitable
sawing pattern in term of the outer
lumber width
Results & Discussion
Sawing Study
POLYGON SAWING
● 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 outerlumbers 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 m3/year
Results & Discussion
Properties Enhancement Study
50
1 hr
2 hrs
3 hrs
WPG (%)
40
30
20
10
0
10%
15%
PF Concentration
20%
● Being impregnated and densified, the
density of OPW increased almost 3x
from 0.37 g/cm3 to almost 1.00 g/cm3.
● 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].
Results & Discussion
Properties Enhancement Study
50
1 hr
2 hrs
3 hrs
ASE (%)
40
30
20
10
0
10%
15%
PF Concentration
20%
● 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
Results & Discussion
Properties Enhancement Study
The mechanical properties of treated OPW were substantially improved
3000
16
2 hrs
3 hrs
1 hr
2 hrs
3 hrs
2500
Shear strength (MPa)
Compression // grain (MPa)
1 hr
2000
1500
1000
12
8
4
500
Ctr=
Ctr=
0
170
10%
15%
PF Concentration
20%
1.85
0
10%
15%
20%
PF Concentration
● 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)
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
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 m3 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.
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.