7000

 S6000 A
 Z*
 r 5000

 S4000

 3000
 4--
 u2000

 1000
 0
 0


 -20000
 E" B

 -16000

 (D
 C
 r 12000
 0)

 p 8000 -


 LL 00


 0
 TABR ANAE CASE BEIP GUSS TETP EUGN ASPC
 Species

Figure 1-1. Means (+ 1 SD) material biomechanical traits of stems for seedlings of eight
 tree species ordered from left to right by increasing shade tolerance at 1 mo
 (T1, filled bars), and 6 mos (T2, open bars) after leaf expansion. A) Young's
 modulus of elasticity (E). B) Fracture toughness. Asterisks indicate significant
 difference between T1 and T2 (P value < 0.006 with Bonferroni correction).
 Refer to Table 1-1 for species codes. No data available for stem toughness of
 GUSS at T2 because the size of the stems exceed size capacity of the tester
 (3 mm diameter).