In a recent JIinl article, Singer et al. (1994) report results of a willow (S&X spp.) study on the northern (ungulate winter) range of YeIlowstone National Park (YNP) and immediate vicinity. The authors measured production, forage quality, moisture stress, and tannin content of growth shoots, all in relation to ungulate browsing, browsing-induced architectural variation, and altitude. In our view, the evidence presented does not support a number of the major inferences drawn, and in fact points to what in our judgment are more probable ones.