Andrew Peterson - Planting Trees Chords & Tabs

He might have this in an alternate tuning, but I can't figure out which one...
[ Tab from: https://www.guitartabs.cc/tabs/a/andrew_peterson/planting_trees_tab.html ]
e|-------------------------------------------------------------------------|
B|-------------------------------------------------------------------------|
G|-------------------------------0---0-------0---0-------0-------0---------|
D|-------0---0-------0---0-----4---4-------4---4-------4---4--2h4-4-0----0-|
A|---0h4---4-----0h4---4-----5-----------5-----------5----------------0h2--|
E|-3-----------3-----------5-----------5-----------0-----------------------|

That's basically the whole song. Play the intro about 3 times for the verse.