search for: phloem

Hello, This is my first time addressing such a big audience so apologies in advance in case I fail to formulate this question. I am working with 13 species of trees, and the data I have are: 1 continuous (phenolic concentration in xylem and in phloem) and 2 categorical variables: lineage (3 subclades) and habitat (fire and non fire). I am trying to see how species can be splitted 'objectively' based on these variables. I tried to do a regression tree using the rpart library, but repeatedly got the following answer, even when I trie...