This result states energy quantization for bubble trees of harmonic maps: given u k: N be a sequence of smooth harmonic maps from a closed Riemannian surface to a compact real-analytic target, with k E(u k; )< . Assume the following no-neck energy.... It is useful in harmonic map theory and elliptic regularity, where variational identities, curvature estimates, and compactness arguments control geometric objects.