A realistic 3D model of a large red oak tree in winter. The tree should have a thick, sturdy trunk with deeply textured bark and strong, spreading branches that form a broad, rounded canopy. The branches are mostly bare but should include a scattering of dry, a few brown oak leaves still clinging to the tips, typical of red oaks in winter. The silhouette should feel wide and expansive, with natural asymmetry in branch placement. The bark should use PBR textures with rough, cracked details for realism. The model should be optimized for Unreal Engine 5 with clean geometry and realistic materials. Include only the tree itself—no background, buildings, or ground.