interperting a regression tree

hello
i am trying to decipher a dendrogram i have from performing a 'tree'. (attached file) 
my response variable is factored - low, medium and high threat and the 8 explanatory variables are numeric values. 
 
i could do with some help to understand what the values <0.25, <0.5 and <0.75 are on the tree branches? how does one interpret this??? 
 
cheers,
mann
 
 
 
Manju Sharma
Ashoka Trust for Research in Ecology and the Environment,
Banaglore, India