[R] random forest mtry and mse

[David Rogowski]

I have been using random forest on a data set with 226 sites and 36 
explanatory variables (continuous and categorical). When I use 
"tune.randomforest" to determine the best value to use in "mtry" there 
is a fairly consistent and steady decrease in MSE, with the optimum of 
"mtry" usually equal to 1. Why would that occur, and what does it 
signify? What I would assume is that most of my explanatory variables 
have little to no explanatory power. Does that sound about right?

Thanks for any insight that anyone may have.

dave