Two short images sit side by side here: a tree and a river, each described as a person. The alder is an old man with a grey beard, dozing in the sun. He is still, settled, and seems to have nothing left to prove. The river, by contrast, is a child, always moving and always asking questions. The last line, "way to Why," plays on the idea that a child keeps asking "why?" while the river keeps looking for a route onward.
The speaker doesn't comment directly, but the poem seems to watch both with quiet affection. The title, "Timeless," suggests that old age and childhood, stillness and motion, belong together in one scene, and that nature holds both at once. The mood is calm and gently playful. The first stanza feels warm and drowsy, while the second adds a little curiosity and energy. The poem leaves you with a sense of peace, but also of wonder at questions that never quite get answered.