How many Red Maples are in the data frame created in question $1?$

#$3.$ With the data frame created in question $1,$ use the mutate function to add a

# third column$/$variable named "TREE$\_$DBH$\_$CM$"$ to this data frame, which contains

# the TREE$\_$DBH column converted from inches to centimeters.

# Conversion Formula: CM $=$ IN $*2\mathrm{.}54$

# How many trees have diameters greater than $67$ centimeters?