Joining, by = "experiment"
   site experiment length width height manipulation
1     1          1    2.2   1.3    9.6      control
2     1          2    2.1   2.2    7.6         burn
3     1          3    2.7   1.5    2.2      rainout
4     2          1    3.0   4.5    1.5      control
5     2          2    3.1   3.1    4.0         burn
6     2          3    2.5   2.8    3.0      rainout
7     3          1    1.9   1.8    4.5      control
8     3          2    1.1   0.5    2.3         burn
9     3          3    3.5   2.0    7.5      rainout
10    4          1    2.9   2.7    3.2      control
11    4          2    4.5   4.8    6.5         burn
12    4          3    1.2   1.8    2.7      rainout