Oregon Alder in Winter

Without their leaves, deciduous trees could be considered uninteresting in the winter. Yet without the distraction of leaves, one can focus on the beauty, often stark, of the bark, buds, remaining fruits and shape.

The Oregon alder (Alnus rubra) is fascinating in the winter. Alders have male and female parts separate on the same tree. Long, hanging male catkins are produced in the early winter then swell up and release pollen the following spring. Tiny erect female catkins appear at the shoot tips in the early spring. These female catkins ripen to form green, woody conelets that after fertilization ripen into open cone-like structures, called strobiles, with woody scales from which seed-like nuts with thin wing-like are released.

Native to western North America, the Oregon alder is associated with water, growing along streams or swampy areas. The male winter buds are dark red with a pale pubescence and are clustered on red stems. Dark brown strobiles are also present on the tree. The young twigs are mahogany red and shiny while the older twigs are a light ash gray. The light gray or ashy bark is thin and roughened by wart-like excrescences. Lumbermen call this tree a red alder because the underbark is red. Any scratches along the bark reveal this colorful underbark. The catkins, strobiles and color make the Oregon alder an engaging tree, even in the drab winter months.

The pictures were taken at Baum Lake (Lassen County CA). The light gray bark can be discerned behind the strobiles, red male catkins and red stems. The red underbark is conspicuous in the branch, which was felled by a beaver (the gnaw marks are visible – but that is another post).

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