How to jump back to NERDTree from file in tab?

I usually:

1. Choose the needed file.
2. Open it in a tab(t character, by default).

But how I can jump back to NERDTree to open one more file in a tab?

Temporary solution I use now in my .vimrc file:

map <F10> :NERDTree /path/to/root/of/my/project

But it’s not very useful to start navigation again and again from the root directory.