This paper is devoted to the study of the so-called WARM reinforcement models that are generalisations of Pólya's urn. We show that in the graph setting, once the exponent α of the reinforcement function is greater than 2, the stable and critical equilibria can be supported only on spanning forests, and once α>25, on spanning whisker forests. Thus, we prove the whisker forests conjecture from Hofstad et al. [Ann. Appl. Probab. 26(4), 2494-2539 (2016)].