1. Prime in Wraithbone

Tree & ground

1. Tree bark in Wyldwood and moss in AP Speedpaint2 Burnt Moss
2. Mushrooms in Nazdreg Yellow
3. Ground in Cygor Brown
4. Skeletons in Skeleton Horde
5. Rocks in Black Templar then stipple Mechanicus Standard Grey and drybrush Light Grey (or just yolo it with Basilicanum Grey and fix the coffee staining with the drybrush)
6. Drybrush Karak Stone over everything exept leaves

Leaves options

1. Iyanden Yellow
2. Flesh Tearers Red and light drybrush with Fulgrim Pink
3. Ork Flesh and light drybrush with Light Green