An Etymological Dictionary of the German Language/Föhre
Föhre, f., ‘fir,’ from MidHG. vorhe, OHG. forha, f., ‘pine-tree’; corresponding to AS. furh, f., E. fir (MidE. firre, formed from Dan. fyr), OIc. fura, f., ‘fir’; Goth. *faúrhus, f., is wanting. If the initial f is to be regarded as in vier related to Lat. quattuor, Föhre may be connected with Lat. quercus, ‘oak’; for the change of meaning Eiche and Tanne might be compared. In earlier ModHG. Ferch, ‘oak,’ is also recorded once, and is akin to OHG. vereh-eih, Lomb. fereha, ‘æsculus.’ Thus the connection between Föhre and quercus (pre-Teut. qṛku-) is certain. In any case, Feuer is not a cognate. Fichte, Birke, Buche, Föhre are the few names of trees whose existence can be traced beyond Teut. Comp. also Kiefer.