Você deseja que a -R
mude para less
.
Na página less
man:
-R or --RAW-CONTROL-CHARS Like -r, but only ANSI "color" escape sequences are output in raw" form. Unlike -r, the screen appearance is maintained correctly in most cases. ANSI "color" escape sequences are sequences of the form:
ESC [ ... m
Então você precisa
tree -C public/ | less -R