Chaotic Good and very very heavy. This is not a creature you want to anger. Use the "Treant battle" SoundSet to mix the sounds of this spectacular of combatants in with other battles when the PCs manage to get them to fight along side them, or just by itself if the PCs manage to get them to attack them. Swinging round an axe threateningly in an old growth forest will tend to have that affect.
From the Monster Manual:
Treants are awakened trees that dwell in ancient forests. Although treants prefer to while away the days, months, and years in quiet contemplation, they fiercely protect their woodland demesnes from outside threats.
This SoundSet will appear by default in the Syrinscape Fantasy Player app, but you can make it appear in any of the apps by using the Campaign Manager.
Wind through the pines
Treant ground crash
Treant slam attacks
Treant body noises
Bass - pulsating drone
This SoundSet was imagined, compiled, designed, created, mixed, and finished by Benjamin Loomes of syrinscape.com, using samples created by him and also the following list of samples from the collaborative Internet database of creative-commons licensed sounds freesound.org:
"cicada" by "exomene"
Key: "sample name" by "username". Find user freesound accounts under http://www.freesound.org/people/[username]
"Big bass drone – pulsating" sounds created by Benjamin Loomes of Syrinscape
“Drum" sounds created by Benjamin Loomes of Syrinscape
“Voice of Seeded” people by Tristan Meadows, Morgan Rands, Randi Coleman, Anna Rands
“Wind In The Leaves In The Trees” sounds created by Benjamin Loomes of Syrinscape
Music composed, performed, and recorded by Benjamin Loomes for Syrinscape
Oneshot art created by Karen Loomes for Syrinscape using art supplied by Wizards of the Coast LLC. ©2018
DUNGEONS & DRAGONS, D&D, their respective logos, and the dragon ampersand, are registered trademarks of Wizards of the Coast LLC. ©2018 Wizards of the Coast. All rights reserved.