might be something created as a easter egg

Wise mystical tree

This is most likely caused by something else you're subscribed to. Open the in-game console (Shift+Esc) and enter these commands, one line at a time:
This will display some green text that tells you where this material and texture are being loaded from. By default, it should be a path containing GarrysMod\sourceengine\hl2_misc.vpk or GarrysMod\sourceengine\hl2_textures.vpk. In your case, it will probably show the name of an addon. Disabling or unsubscribing from that addon and then restarting the game should restore the tree to its intended look.

引用自 Blueberry_pie：

This is most likely caused by something else you're subscribed to. Open the in-game console (Shift+Esc) and enter these commands, one line at a time:

whereis materials/models/props_foliage/oak_tree01.vmt

whereis materials/models/props_foliage/tree_deciduous_01a_trunk.vtf

This will display some green text that tells you where this material and texture are being loaded from. By default, it should be a path containing GarrysMod\sourceengine\hl2_misc.vpk or GarrysMod\sourceengine\hl2_textures.vpk. In your case, it will probably show the name of an addon. Disabling or unsubscribing from that addon and then restarting the game should restore the tree to its intended look.

Removed the mods that were affecting the textures and it's still there. Reinstalled the map and verified the integrity of my game files, neither of which worked.

引用自 ImThing2：

Removed the mods that were affecting the textures and it's still there. Reinstalled the map and verified the integrity of my game files, neither of which worked.

Did you make sure to restart the game? What does it say when you run these commands again?

引用自 Blueberry_pie：

引用自 ImThing2：

Removed the mods that were affecting the textures and it's still there. Reinstalled the map and verified the integrity of my game files, neither of which worked.

Did you make sure to restart the game? What does it say when you run these commands again?

Yes, i restarted the game every time i removed a mod.

Here's what comes up in the command box.

whereis materials/models/props_foliage/oak_tree01.vmt

/Steam/steamapps/common/GarrysMod/sourceengine/hl2_misc.vpk/materials/models/props_foliage/oak_tree01.vmt

whereis materials/models/props_foliage/tree_deciduous_01a_trunk.vtf

/Steam/steamapps/common/GarrysMod/sourceengine/hl2_textures.vpk/materials/models/props_foliage/tree_deciduous_01a_trunk.vtf

I've also removed multiple mods that were updated recently, with no luck.

Welp. Found out what was causing it the problem.

https://psteamcommunity.yuanyoumao.com/sharedfiles/filedetails/?id=2875297603

Didn't know i had this installed. Thanks for your help though.

Ah, the author must have modified the model itself and made it reference a different material. That would explain why the commands didn't find anything. Glad to hear you solved it.

this is the best discussion i have ever seen