This worked for me:

cd to /usr/local/bin and run

sudo ln -s /Applications/Sourcetree.app/Contents/Resources/stree

stree runs completely normally for me after doing that.

I am on 3.0.1 and am getting this issue when installing command line tools 

Installation Failed

Failed to install command line tools, please see the system log for details.

The command line tools will install over the old ones. That said, there's a bug in 3.0 that prevents them from working properly. We've fixed it for 3.0.1 (currently in beta) and will begin rolling that out to all users this week.

This doesn't work as expected? "stree" command now opens SourceTree, but "stree ." fails to open the current folder in SourceTree which is surely the main use case.

Will have to go back to the alias workaround. How to uninstall the command line tools?

Brian, thank you.

I appreciate this specific information, over the previous "I'll see whether we can get it into the release". You say, "previously noted", but that was 3 months ago, so please forgive us for thinking it was vaporware.

As previously noted, this is fixed for the next major release.

It's hard to assume that the SourceTree team cares, because if they did, they'd fix it.

Also confirmed on 10.14, so reached a point where this bug was not fixed while Apple did 4 major OS releases. Maybe tweeting would help getting priorities right.

Confirmed on 10.13.4

I'll see whether we can get it into the release in progress or if we'll wait a little bit and bundle with other fixes.

Looks like this affects all Homebrew users and connected with /usr/local/bin permissions set by brew. However, you can use `brew cask` which will handle symlinks for command-line tools automatically: `brew cask install sourcetree` (you can use `stree` from command line immediately). So I am not sure this should be considered a Sourcetree bug, just use brew-way installation if you use Homebrew on the machine to avoid this.