Shoots of hope in Appalachian swamp as US larch tree is rescued from beavers

Though protected in a cool, damp frost pocket', beaver dams are restricting water flow, threatening Maryland's deciduous conifers

Gripping the long branch of a speckled alder tree, ecologist Deborah Landau slowly steps into the waist-deep murky water. You can't see anything, so watch your step," she warns as she makes her way through the chilly labyrinth of the Finzel swamp preserve in Maryland. The swamp is a meditation for the senses: the sweet aroma of red spruce, the call of the locally rare alder flycatcher and an array of colour in what appears as endless blueberry and rhododendron shrubs.

The preserve, owned by The Nature Conservancy (TNC) in the central Appalachians of far western Maryland in the US, protects a rare boreal fen. Its most notable resident is the American larch (Larix laricina), or tamarack tree, a deciduous conifer that is the reason for Landau's sojourn in the swamp. Lying within a frost pocket" - a microclimate where cold air is trapped by the adjoining slopes and subject to frequent frosts - Finzel swamp provides a favourable year-round climate for the locally endangered larch and other more northern flora and fauna. It is as if a piece of the Pleistocene survived the warming epoch to remind us what life was once like in these ancient mountains.