# white alder (*Alnus rhombifolia*) The white alder is a tall tree with smooth, light-colored bark and green leaves. It grows near rivers and streams, providing shade and homes for many animals. - **Category:** [Plants](https://www.snappit.app/explore/categories/plant) - **Rarity:** Common - **Danger:** 1/5 · Very low - **Snaps:** 2 - **Habitat:** Wetlands ![white alder](https://commons.wikimedia.org/w/index.php?title=Special:Redirect/file/Alnus_rhombifolia_NPS.jpg&width=800) Photo: US NPS Santa Monica Mountains National Recreation Area \[2\], Public domain · [Wikimedia Commons](https://commons.wikimedia.org/wiki/File:Alnus_rhombifolia_NPS.jpg) ## Appearance The white alder is a medium-sized tree with smooth, whitish-gray bark and an often straight trunk. Its bright green, oval leaves have toothed edges, turning yellow in autumn. Dangling yellow-brown male catkins and small, reddish-brown female cone-like structures appear in early spring. ## Taxonomy - **Kingdom:** Plantae - **Phylum:** Tracheophyta - **Class:** Magnoliopsida - **Order:** Fagales - **Family:** Betulaceae - **Genus:** Alnus ## Interesting facts - Alder cones release tiny winged seeds that can float on water, spreading new trees downstream! - Its wood is often used to smoke fish, giving them a delicious, savory flavor! - Look closely at its roots; they have tiny bumps that are homes for helpful nitrogen-fixing bacteria! - The bark was historically used by Native Americans to make a reddish-brown dye for baskets and clothing. ## Special abilities - **Soil Builder:** White alder can partner with special root bacteria to pull nitrogen from the air, enriching poor soils for itself and other plants. - **River Protector:** White alder has strong root systems that help stabilize riverbanks and stream beds, preventing soil erosion during floods. - **Rapid Grower:** White alder can grow very quickly, allowing it to quickly establish itself and compete for sunlight in its preferred watery habitats. ## Measurements & details - **Height:** 1500-2500 cm - **Spread:** 800-1500 cm - **Flower Size:** 1-2 cm - **Bloom Season:** Late Winter to Early Spring - **Edible:** No - **Toxicity:** None - **Lifecycle:** Perennial - **Pollination Method:** Wind ## Ecological connections - **Symbiotic with:** Nitrogen-fixing bacteria (*Frankia alni*) — Bacteria in root nodules fix nitrogen for the tree. - **Eats:** [American Beaver](https://www.snappit.app/explore/american-beaver) (*Castor canadensis*) — Beavers may cut down and eat parts of alder trees. - **Eats:** [Elk](https://www.snappit.app/explore/elk) (*Cervus elaphus*) — Elk browse on the twigs and foliage, especially in winter. - **Shelter:** [Western Gray Squirrel](https://www.snappit.app/explore/western-gray-squirrel) (*Sciurus griseus*) — Squirrels build nests and find cover in alder branches. ## Traits - [Deciduous](https://www.snappit.app/explore/traits/deciduous): Deciduous plants periodically shed all their leaves, typically during autumn or dry seasons. - [Nitrogen Fixing](https://www.snappit.app/explore/traits/nitrogen-fixing): Describes organisms capable of converting atmospheric nitrogen into compounds usable by plants. - [Broadleaf Tree](https://www.snappit.app/explore/traits/broadleaf-tree): Broadleaf trees are angiosperms characterized by flat, wide leaves that are typically shed annually in temperate climates. - [Fall Color](https://www.snappit.app/explore/traits/fall-color): Fall color refers to the seasonal change in foliage pigmentation, primarily in deciduous plants, displaying vibrant hues. - [Rapid Growing](https://www.snappit.app/explore/traits/rapid-growing): Rapid growing plants exhibit accelerated growth rates, quickly increasing in size and biomass within a short period. - [Timber](https://www.snappit.app/explore/traits/timber): Timber refers to wood that has been prepared for use in building and carpentry. - [Wetland](https://www.snappit.app/explore/traits/wetland): This habitat trait identifies species found in wetlands, which are areas of land saturated with water, either permanently or seasonally, including marshes, swamps, and bogs. - [Keystone Species](https://www.snappit.app/explore/traits/keystone-species): Describes a species whose presence and role have a disproportionately large effect on its environment. ## Collections - [Plants](https://www.snappit.app/explore/collections/plants) ## Safety **Danger:** 1/5 · Very low Stay on paths and don't climb trees without an adult's help. ## Frequently Asked Questions ### How to identify white alder? Start with the whole plant, then compare leaf arrangement, leaf edges, stems and any flowers or fruit. Opposite leaves grow in pairs; alternate leaves come one at a time along the stem. These details tell you far more together than a single green leaf does. Plant Identifier: upload a photo and compare the visible details. ### How tall is white alder? 1500-2500 cm ### How wide does white alder spread? 800-1500 cm ### How big are the flowers on white alder? 1-2 cm ### When does white alder bloom? Late Winter to Early Spring ### Is white alder edible? No ### Is white alder toxic? None ### What is white alder's lifecycle? Perennial ## Where to spot - [Jasper Ridge Biological Preserve](https://www.snappit.app/guides/places/jasper-ridge-biological-preserve) — California, US · Nature Reserve - [Crystal Lake Recreation Area](https://www.snappit.app/guides/places/crystal-lake-recreation-area) — California, US · Nature Reserve - [Charbonneau Park](https://www.snappit.app/guides/places/charbonneau-park) — Washington, US · Park [View all places to see white alder](https://www.snappit.app/guides/where-to-see/white-alder) ## More Plants - [white snakeroot](https://www.snappit.app/explore/white-snakeroot) (*Ageratina altissima*) - [tree-of-heaven](https://www.snappit.app/explore/tree-of-heaven) (*Ailanthus altissima*) - [western sword fern](https://www.snappit.app/explore/western-sword-fern) (*Polystichum munitum*) - [common milkweed](https://www.snappit.app/explore/common-milkweed) (*Asclepias syriaca*) --- Source: [White Alder: Facts & Places to See — Snappit](https://www.snappit.app/explore/white-alder)