Titles can be set on treemaps easily if we keep in mind margins.
Normally we simply set titles by using:
title: {
text:"Title text here"
}
For treemaps, this is only half the solution. We also have to set margins so that the treemap title is revealed.
Setting margins for title would look something like this:
plotarea: {
margin:"40 0 0 0"
}
Using both these code blocks we can see the title for treemaps. Here is an example of how treemap is set:
DEMO