Pinus and quercus are both fourth declination, not second, but there seem to be some elements of the second declination that have been included at some point (pini/pinorum/pinis and querci/quercorum) which muddy the waters a bit.
"abl. sing. only pinu; gen. and abl. plur. pinorum and pinis)", but then it goes on to cite the accusative plural pinos in Virgil. And that note implies a strict distinction between dative plural pinibus and ablative pinis, which seems weird. Not that the rest of it isn't weird, I guess.
(As an aside, the note for quercus that "dat. and abl. plural do not occur"... I can believe that a lack of genitive and dative forms for vis is a fact about the language. Dative and ablative plural forms existing for pine trees, but not oak trees, feels more like a coincidence of the historical record than a fact about the language.)