This template's initial visibility currently defaults to autocollapse, meaning that if there is another item on the page (a navbox, sidebar, or table with the attribute), it is hidden apart from its title bar; if not, it is fully visible.
To change this template's initial visibility, the |state= parameter may be used:
{{Tree class trawler|state=collapsed}} will show the template collapsed, i.e. hidden apart from its title bar.{{Tree class trawler|state=expanded}} will show the template expanded, i.e. fully visible.