Treatment

Clam shell area (cm²)^a

1 yr-old

2 yr-old

3 yr-old

4 yr-old

5 yr-old

Z. japonica

0.38

1.13

1.95

3.33

3.81

No Z. japonica

0.47

1.69

2.62

3.57

4.15

T test significance

0.001

0.04

0.006

0.1

0.1