Probably the biggest reason black bears make their beds near big white pines is the white pine's bark. Old white pines have deeply-furrowed, strong bark that make them easier for cubs to climb for safe refuge. Cubs often fall from trees with flaky bark, like spruces, jack pines, and red pines, and the often fall from trees with smooth bark like birches and the upper branches of aspens.
White pines have another advantage for bears in spring before deciduous trees leaf out. White pines offer shade to escaping cubs that may spend hours in trees until danger passes. Bear fur can reach 185 degrees Fahrenheit in the sun. The need for shade becomes a matter of life and death when panting can no longer keep body temperature below 104 degrees.