“Louisiana State University
...
The balsa wood has a fairly low modulus and strength in the direction perpendicular to the fibers, whereas the modulus and strength parallel to the fiber direction are relatively high.”
( http://etd.lsu.edu/docs/available/etd-04292004-103556/unrest... )


Japan Society of Civil Engineers
A Bridge Made of Wood
...
Among various strengths in the direction of the fiber, tension is the largest, next is bending, and compression is about 1/3 ~ 2/3 of the tension.
...
On the other hand, values of Young’s modulus and the tension strength, perpendicular to the fiber direction are about 1/10 ~ 1/20 of those in the fiber direction.
( http://www.jsce-int.org/civil_engineering/2005/1-2.pdf )