Speaker : Pei-Yu Kuo Plantation Density and Thinning Effect on
the Length of Tracheid and Maturing Age of Japanese- cedar Grown in
Taiwan
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I ntroduction Japanese-cedar is one of the important resources
in Taiwan. Large percentage of plantation Even-aged Low economic
value Plantation density Thinning intensity Anatomy of the
wood
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Material and Method site location
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Material and Method data of the site Site Original numbers 1968
Light thinning treatment 1990 Intensity of thinning treatments 2001
Average Basel Area (cm 2 ) A1 2200 trees / ha Type A 550 trees / ha
Heavy thinning (40%)621.93 A2Medium thinning (25%)600.45 A3Light
thinning (10%)571.28 B1 3000 trees / ha Type B 750 trees / ha
Medium thinning (25%)587.50 B2 Light thinning (10%)504.32 B3No
thinning477.23
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Result and Discussion 1 The anatomy from pith to bark and their
relationship
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Result and Discussion Ring number from pith (years) length of
tracheid (mm) The growing curve of trachied is a log curve
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Result and Discussion The MFA decreased rapidly at first and
then remained constant. Ring number from pith (years)
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Result and Discussion The degree of MFA and the length of
tracheid have contrary trend.
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Result and Discussion Second thinning First thinning Plantation
density 33 rd to 36 th 23 rd to 32 nd 1 st to 22 nd 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 2 Three methods to distinguish the
maturing age
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Result and Discussion Ring number from pith (years) length of
tracheid (mm) Method 1 : the elongation ratio of log curve is less
than 1%
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Result and Discussion Ring number from pith (years) length of
tracheid (mm) Method 2 : Reducing the numbers of sample
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Result and Discussion Ring number from pith (years)
Aaccumulated width of annual ring (mm) Method 3 : the elongation
ratio of log curve is less than 3%
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Result and Discussion AB Method 1 a year 20 22161722 Method 2 a
year 191822181618 Method 3 a year 19 17181622 Tracheid length (mm)
Mature a 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 Juvenile b 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 Microfibril Mature a 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 Juvenile b 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
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The length of tracheid decreases with the increasing MFA. It
shows negative linear regression (R 2 =0.71) when the length of
tracheid is versus the angle of MFA. 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 The anatomy from pith to bark and their relationship
The effect of planation density and thinning
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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. Conclusions Three methods to
distinguish the maturing age
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Thank you for your attention Comments and Questions are
Welcome