  Thermal transport properties of the FPU $\beta$ model with a quadratic
pinning term are investigated for various couplings and temperatures. In
particular, the size dependence of the thermal conductivity, $\kappa\propto
L^\alpha$, is studied. $\alpha$ agrees with that of the FPU $\beta$ model (with
no pinning) at high temperatures but decreases at low temperatures. This
crossover behavior occurs at a temperature depending on the strength of the
quadratic pinning.
