Limber, lumber. Limber, limb. Trees, humans.

Angela Pelster's "Limber" is a short collection of prose verging on poetry. It is a mesmerizing workout for the mind, invoking wordplay and mental leaps. Paragraphs can leave you breathless, brain working like a muscle — or the lignin of a tree.

Trees are the stars of the book, from the aspen poplars of Pelster's native Alberta to the cinnabar that gives the moon its reddish glow. Yes, trees inhabit the lunar landscape in the "Limber" universe. It's a universe in which trees are fully animated, able to bite, communicate, injure and invent.

The title is drawn from the third essay, set in a mining town of the Canadian Rockies, where a limber pine takes root and precariously but stubbornly holds on for centuries. Here the language becomes biblical, recounting migrations, plagues, divisions, songs and the life of miners underground, where "the dark focused their vision on the one thing, the smooth black coal stamped with curling fronds of fern or ancient maple leaves." Pelster's storytelling is like a collision of "The Wizard of Oz" and the Book of Revelation.

The collection is labeled "essays," but don't look to "Limber" for a reference on anything except perhaps the human history of trying to make meaning, often to disastrous effect. Meditation, memoir, parody, stories morphing into parables and myth all appear, haunting, urgent and beautiful. Points of view range from an abused teen picking Saskatoon berries to an astronaut taking tree seeds into orbit. Most pieces defy categorization. All revel in the flexibility of human language and thought.

In the background, we see glimpses of Pelster herself, growing up in a family of six on a camper trip to Disneyland through the California redwoods, learning in Bible college the forbidden nature of figs, listening to an Iowa maple full of frogs, contemplating the night sky in Greece, compulsively searching the Internet for the identification of a tree next to a hockey rink in the news, sleeping in the winter basement of her mother's house with her daughter after a divorce. Always she is tuned to the trees around her, whether branches or roots.

"Limber," by Angela Pelster

"A tree is not a metaphor," she writes of a maple in her yard. "A tree is a tree, and we are both only one strong wind away from falling."

Pelster writes essays in an older sense of the word, to try or test. In "Limber," she succeeds at using language to perceive the world and to adapt, to entertain and engage. She shakes herself and us out of rigid habits of thought and stretches our minds.

Gayla Marty is the author of "Memory of Trees: A Daughter's Story of a Family Farm." She lives in Minneapolis.