It's somewhat easier to register a copyright than a trademark. Both require that you fill out a form.
While most copyrights are uncontroversial--it's unlikely that two people will write exactly the same novel--trademarks are examined by an attourney and subjected to a 30 day opposition period, in which anyone can oppose the trademark registration.
They can do so if they believe that:
- the trademark is too similar to one already in use
- too descriptive--using words that others with similar products need to use
Because there's so much room for overlap, the trademark approval process is longer and more rigorous.