It always depends. If you NEVER want to show all choices, then
independent trees is probably OK. But I would probably have a single
tree - and then a helper method that lets me get all the first level
children easily. And you may want another helper that would give the
''root'' of the subtree, something like
''bike_class'' that would return
Road, Mountain, etc. 
Quoting Mohammad Abed <mabed at starpower.net>:> Hi,
> 
> What would be a better design for this tree. I have Categories of bicycles,
> there are a lot more categories than sown. Should I create a root category
> as in the Readme file like this. I''ll be using these trees for
dependent
> drop-downs, menus, etc...
> 
> Bicycle_Categories
>     |
>     |_ Road
>       |_ Steel
>       |_ Titanium
>       |_ Carbon Fiber
>     |_ Mountain
>       |_ Steel
>       |_ Aluminum
>       |_ Scandium
> 
> 
> Or just create independent trees without a main root.
> 
>     |_ Road
>       |_ Steel
>       |_ Titanium
>       |_ Carbon Fiber
>     |_ Mountain
>       |_ Steel
>       |_ Aluminum
>       |_ Scandium