(a.) Falling down.

arborary arboreal arboreous arborescent arboresque arborical arboriform brittle bushlike bushy capricious changeable citrous collapsing coniferous corruptible declining declivitous decurrent dendriform dendritic dendroid descendant descending down down-reaching downcoming downfalling downgoing downhill downsinking downward drooping dropping dying ephemeral evanescent evergreen fading falling fickle fleeting flitting fly-by-night flying fragile frail fugacious fugitive half-hardy hardwood hardy impermanent impetuous impulsive inconstant insubstantial momentary mortal mutable nondeciduous nondurable nonpermanent on the descendant on the downgrade passing perennial perishable piny plummeting plunging sagging scrubbly scrubby scrublike setting short-lived shrubby shrublike sinking softwood submerging subsiding temporal temporary tottering transient transitive transitory treelike tumbledown undurable unenduring unstable volatile