Plantation Density and Thinning
Effect on the Length of Tracheid
and Maturing Age of Japanese-
cedar Grown in Taiwan
Speaker : Pei-Yu Kuo
Introduction
Large percentage
of plantation
Even-aged
Low economic value
Plantation density
Thinning intensity
Anatomy of the wood
Japanese-cedar is one of the important resources in Taiwan.
Material and Method – site location
Material and Method – data of the site
Original numbers
Site
（1968）
Light thinning
treatment
（1990）
A1
A2
2200 trees / ha
（Type A）
Intensity of thinning
treatments
（2001）
Average
Basel Area
(cm2)
Heavy thinning (40%)
621.93
550 trees / ha Medium thinning (25%)
600.45
A3
Light thinning (10%)
571.28
B1
Medium thinning (25%)
587.50
Light thinning (10%)
504.32
No thinning
477.23
B2
B3
3000 trees / ha
（Type B）
750 trees / ha
Result and Discussion 1
The anatomy from pith to bark and their relationship
tracheid length (mm)
of tracheid (mm)
length
Result and Discussion
4.00
3.00
2.00
y = 0.6767Ln(x) + 0.9719
R2 = 0.9714
1.00
0.00
0
5
10
15
20
25
30
Ring number
from
pith(years)
Ring number
from
pith
The growing curve of trachied is a log curve
35
Result and Discussion
MFA (degree)
50
y = -7.2902Ln(x) + 39.27
R2 = 0.9406
40
30
20
10
0
0
5
10
15
20
25
30
35
Ringnumber
number from
from pith
Ring
pith(years)
(years)
The MFA decreased rapidly at first and then remained constant.
MFA(degree)
Result and Discussion
50
45
40
35
30
25
20
15
10
5
0
y = -10.649x + 50.009
R2 = 0.7126
0
1
2
3
4
tracheid length (mm)
The degree of MFA and the length of tracheid have contrary trend.
Result and Discussion
33rd to 36th
23rd to 32nd
1st to 22nd
Second
thinning
First
thinning
Plantation
density
We not only discuss the average data, but also separate
those data into three sections and discuss the effect of
each treatment.
Result and Discussion
Tracheid length
Average
1st – 22nd
23rd – 32nd
33rd – 36th
A1
2.65 ± 0.46
2.26 ± 0.43
3.02 ± 0.10
2.99 ± 0.11
A2
2.65 ± 0.65
2.27 ± 0.65
3.10 ± 0.16
3.19 ± 0.16
A3
2.63 ± 0.50
2.20 ± 0.42
3.03 ± 0.11
3.12 ± 0.12
B1
2.63 ± 0.58
2.28 ± 0.60
3.04 ± 0.06
3.06 ± 0.07
B2
2.73 ± 0.57
2.42 ± 0.62
3.06 ± 0.10
3.20 ± 0.13
B3
2.68 ± 0.64
2.26 ± 0.64
3.05 ± 0.13
3.23 ± 0.04
Result and Discussion 2
Three methods to distinguish the maturing age
Result and Discussion
tracheid
(mm)(mm)
tracheid
of length
length
4.00
3.00
2.00
y = 0.6767Ln(x) + 0.9719
R2 = 0.9714
1.00
0.00
0
5
10
15
20
25
Ring number
fromfrom
pithpith
(years)
Ring number
30
35
Method 1 : the elongation ratio of log curve is less than 1%
Result and Discussion
(mm)
of tracheid
length
tracheid
length (mm)
3.5
3
2.5
y = 0.1431x + 1.1541
2
2
R = 0.9344
1.5
The tracheid length between
1995 and 2000
1
from pith to 10th ring
0.5
0
0
7
14
21
28
Ring number
from
pith
pith(years)
from
Ring number
Method 2 : Reducing the numbers of sample
35
Aaccumulated width of annual ring (mm)
Result and Discussion
14
y = 3.8373Ln(x) - 1.5889
R2 = 0.9786
12
10
8
6
4
2
0
1
4
7
10 13 16 19 22 25
Ring number from pith (years)
28
31
Method 3 : the elongation ratio of log curve is less than 3%
Result and Discussion
A
B
Method 1 a（year）
20
20
22
16
17
22
Method 2 a（year）
19
18
22
18
16
18
Method 3 a（year）
19
19
17
18
16
22
Maturea
Wood
3.00
±0.09
3.11
±0.15
3.03
±0.14
3.02
±0.07
3.08
±0.11
3.09
±0.14
Juvenileb
Wood
2.24
±0.37
2.13
±0.62
2.25
±0.42
2.04
±0.53
2.12
±0.54
2.01
±0.59
Maturea
Wood
14.09
±3.17
15.74
±2.03
17.14
±1.41
17.26
±1.5
17.35
±1.96
16.63
±1.20
Juvenileb
Wood
24.87
±9.14
25.35
±6.00
24.39
±5.08
26.00
±5.99
28.07
±8.77
27.06
±6.85
Tracheid
length
(mm)
Microfibril
Conclusions
The anatomy from pith to bark and their relationship
The length of tracheid decreases with the increasing MFA. It
shows negative linear regression (R2=0.71) when the length of
tracheid is versus the angle of MFA.
The effect of planation density and thinning
The average lengths of high plantation density or one to twenty years
grown tracheid have significant longer lengths than low plantation
density tracheid. But, there is no significant difference in thinning
treatment.
Conclusions
Three methods to distinguish the maturing age
Using the three mentioned methods to determine the age of
maturity, we can conclude that it is 19 years old. Morerover, there
is no significant difference between the results of these methods
above to judge the age. No matter in the length of tracheid or the
angle of MFA, mature wood has significant longer tracheid length
and smaller MFA than juvenile wood.
Thank you for your attention
Comments and Questions are Welcome