The Garden is down to the Final Tree, and so It must be protected or it would mean the End of your Ashra.

You have volunteered yourself as the Gardener, after the Previous one disappeared, and so you are the one who is now responsible to Feed your people, and so that is what You must do, to make sure that your people continue to Live on to the Next Day. 

You were always told the Outside World was dangerous but even now you can't fully comprehend what that means. 

But you will.

Soon enough.