use warnings;
use strict;

my @terms = qw( Maple Oak walnut pine juniper );

my $text;
{
    #slurp the whole file
    local $/;
    $text = <DATA>;
}
if ( $text =~ /upperboundary(.+)lowerboundary/s ) {
    $text = $1;
    print $text, "\n\n";
}
else {
    die "no match";
}
foreach my $term (@terms) {
    if ( $text =~ /($term)/is ) {
        print "$1\n";
    }
}

__DATA__
upperboundary
The book Hiking the Red, A Complete Trail Guide To Kentucky's Red River Gorge 
made it a point to describe the habitat and the diverse species of trees that 
one is likely to encounter at the Red. According to the authors, the species 
of trees found in the Daniel Boone National Forest includes beech, sugar 
maples, white pines, hemlock, several types of oak, and hickory. These trees 
provide habitat for an estimated 67 different species of reptiles and 
amphibians, 46 species of mammals, and 100 species of birds. 
lowerboundary