8 Figure 3-A2. The flitches were cut in segments of 1 cm thick from pith to bark
and numbered consecutively. Segments for determination of fibre length and microfibril angle were kept in green condition Figure 3-A3. From the B1 discs,
boards of 2.5 cm width were band sawn bark to bark through the pith for specimens of bending strength MOE and MOR tests Figure 3-B2. The boards
were also re-sawed in segments of 2 cm thick from pith to bark and numbered consecutively. Individual test specimens Figure 3-B3 were carefully air dried to
prevent warping.
Figure 3 Schematic drawing of the preparation of juvenility and bending test specimen for sengon and jabon
2.3.2 Sample Preparation for douglas-fir
The disks of 2 cm thick Figure 4-A1 were cross cut from the middle part 2 m above the ground of the sample log. From the A1 disks, flitches of 2.0 cm
width were prepared from pith to bark for specimens of fiber length, and MFA measurements Figure 4-A2. Douglas fir wood samples were cut according to its
annual ring segments from pith to bark they were numbered conscutively Figure 4-A3. The dimension of each douglas fir sample was 2 cm length x 2
cm width x 1 cm thickness.
Figure 4 Schematic drawing of the preparation of the tracheid length and MFA
measurement test for douglas-fir
Segmented rings from pith Wood disk
A1
B1
1 2 3 4
B2
Bending test specimen
B3 A3
Juvenility test specimen
1 2 3 4 A2
2 cm
A1 A2
Wood disk A3
Annual ring segments from pith to bark
1 2 3 4
2 cm 2 cm
A1
9
2.3.3 Sample preparation for poplar
Logs were peel by using “SEM Automation S500” at LaBoMaP Laboratoire Bourguignon des Matériaux et des Procédés, Ecole National
Superieure d’Arts et Matiers ENSAM Cluny, Bourgogne, France. It could peel
logs from 450 to 850 mm in length and 180 to 500 mm in diameter. Logs were peeled by using a 1° clearance angle, 1 ms
-1
speed and with a moderate pressure rate of 10 to limit lathe check growth and thickness variation Lutz 1974; Feihl
1986; Marchal et al. 2009. Before peeling, each log was holed by 1 cm diameter drill bit from bark to
pith, to mark the radial segment of veneers sample. Each cultivar of poplar logs were peeled with 3 mm thickness. The logs were peeled until the core diameter of
14 cm. Veneers were dried with a vacuum dryer to ensure a flat veneer surface dried until they reached 8 - 10 moisture content. In each radial segment veneer
samples in the size of 10x60 cm and kept in plastic for analyzing fiber length and MFA of poplar.
2.3.4 Density measurements for sengon and jabon
The density profiles from pith to bark were measured using X-ray densitometer at the Institute National de la Recherche Agronomique INRA in
Champenoux, Nancy, France. The A2 fliches were air dried before being sawn into 2-mm thick longitudinal strips with a specially designed pneumatic-carriage
twin-bladed circular saw. The strips were measured for air-dried moisture content. The strips were scanned to estimate the air-dried wood density for each segmented
ring from pith to bark. Density of each 1-cm ring width each segmented ring was determined based on the intra-ring microdensitometric profiles. Density value
kgm
-3
from each segmented ring was obtained and the density profiles were recorded.
2.3.5 Density of solid douglas-fir and poplar
The samples in Figure 2-A3 were weighted air dried weight, then measured theirs length, width and thickness by using caliper. Wood densities
from pith to bark were calculated by using formula Equation 1: ρ =
a r r a r r
o
……………….1
2.3.6 Static bending test measurement
Sengon and jabon air dried bending test specimens which are straight- grained and free from any visible defects, 2×2 cm in cross section, with true radial
and tangential surfaces were prepared for the measurement of bending strength. The bending test specimens were numbered conscutively from the pith to bark.
Static bending tests were conducted on the Instron universal testing machine based on the ASTM D-143 testing procedure.
2.3.7 Fibre length and microfibril angle
Specimens for juvenility test Figure 3-A3 were used to determine fibre length and microfibril angle from the pith to bark. The specimens were macerated
using a cutter based on Schulze’s method of TAPPI T 401 om-88 TAPPI 1991. The small pieces were treated with nitric acid and 0.03 g of potassium chlorate to
dissolve the middle lamella and allow the fibres to become separated from one
