I did a simple experiment with trees: 5 species (`sp`) and two management (`trt`). I assessed the diameter (`diam`) through the time (`month=1:24`) and I'm interesting in the factors interaction effect, I mean if the management is suitable for some species.

The [dataset][1] has some limitations since it is not balanced, so in 2 out of 10  factors combinations (`sp*trt`) I have 4 trees (subjects) and for the rest there are 5 trees: 

           sp    trt trees
    1       A      L     5
    2       A      W     5
    3       B      L     5
    4       B      W     5
    5       C      L     5
    6       C      W     5
    7       P      L     4
    8       P      W     5
    9       T      L     5
    10      T      W     4

I fitted the following model:

    m1 <- lmer(diam ~ trt * sp * month + (1|tree), data = dat1)

I'm  not sure if I'm doing right, mainly if the model is right... 

[![enter image description here][2]][2]


  [1]: https://drive.google.com/open?id=0BzrHpe_fGynadHlpYS1qcGw4WkU
  [2]: https://i.sstatic.net/neZSW.png