Jim Brandenburg / Birch (Betula sp) bark peeling off, Minnesota

Jim Brandenburg / Paper Birch (Betula papyrifera) bark peeling, Listening Point, Ely, Minnesota

Tim Fitzharris / Sycamore (Platanus sp) bark, Great Smoky Mountains National Park, Tennessee

Kevin Schafer / Ponderosa Pine (Pinus ponderosa), Sand Harbor State Park, Lake Tahoe, Nevada

Tim Fitzharris / Western Red Cedar (Thuja plicata) grove of the patriarchs, Mt Rainier National Park, Washington

Tim Fitzharris / Poison Oak (Toxicodendron diversilobum) on Monterey Pine (Pinus radiata) bark, Pt Lobos, California

Mark Moffett / Bark Beetle (Dendroctonus pseudotsugae) larvae with radiating galleries in Douglas Fir (Pseudotsuga menziesii) tree, University of Idaho Forest, Idaho

Jim Brandenburg / Mushroom cluster on tree surface in July, Northwoods, Minnesota

Jim Brandenburg / Paper Birch (Betula papyrifera) peeling bark in forest, White Mountains National Park, New Hampshire

Jim Brandenburg / Red Pine (Pinus resinosa) bark detail, Northwoods, Minnesota

Jim Brandenburg / Birch (Betula sp) tree with peeling bark, Northwoods, Minnesota

Mark Moffett / Bark Beetle (Dendroctonus pseudotsugae) larvae with radiating galleries in Douglas Fir (Pseudotsuga menziesii) tree, Flat Creek, University of Idaho Forest, Idaho