Low-poly cartoon tree trunk with thick gnarled roots spreading at the base, no branches, no leaves, just the main trunk and root system. Style: soft watercolor illustration, warm brown bark texture, slightly stylized for a children's educational app. Height approximately 3–4 meters relative to roots. Export as GLB/GLTF, polygon count under 5000, suitable for WebGL. No foliage, no crown — trunk and roots only.