Hi, this is my first post here but since i'm mainly in the WP business i might answer to this one.
Normally if you have rewrite on in your WordPress (like general > settings > permalink) and any other options set than default, your big tree installation should work since the htaccess check for folder or file presence (via a RewriteCond).
So maybe you just have to activate it (if not) or maybe you have a cache issue with chrome (that stores redirection and stuff like that ...)

For information, the default WordPress .htaccess

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>

# END WordPress

These lines should allow you to access directly to a folder within the wordpress directory/file structure.

RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d

By the way, if anyone has a topic for start with bigtree i appreciate