No one grieves onscreen quite like Charlotte Gainsbourg, here playing Dawn, made a widow within the first 10 minutes of The Tree. When not sobbing or sleeping, she expends her depleted energy wrangling her four kids, ranging from toddler to teenager, who scamper around their stilt-built house in Boonah, a tiny, dusty town in Queensland, Australia. Dawn’s only daughter, eight-year-old Simone (Morgana Davies), manages her sorrow by insisting that her father is communicating with her from high up in the Moreton Bay fig tree in the yard; soon, Mom is talking to branches, too. In her second film (after 2003’s Since Otar Left), writer-director Julie Bertuccelli, adapting Judy Pascoe’s 2002 novel, Our Father Who Art in the Tree, is sometimes partial to clumsy dialogue (“Would you say we’re a happy family?” Dawn asks her oldest) and scattershot pacing. But Gainsbourg and Davies, almost feral with her mass of untamed blond curls, make a memorable parent-child pair, first as supernatural-secret-sharing friends, then as foes, especially after Dawn takes up with the plumbing-supply guy. The massive timber becomes the family’s most formidable enemy, its roots clogging up drainage systems and its branches crashing through bedrooms. If the message of “Let go and move on” is suggested a little too obviously by Bertuccelli’s destructive title character, it at least serves as the arboreal opposite to Terrence Malick’s cosmic mumbo-jumbo—The Tree of Death.