Recommended Shade-Loving Native Trees for the Northern California Coast Region

California has tremendous ecological and biological diversity. It contains offshore islands and coastal lowlands, large alluvial valleys, forested mountain ranges, deserts, and various aquatic habitats.

California is divided into 13 main ecological regions and 177 sub-regions. Unique in topography, soil depth, pH, elevation, light, and hydrology, each region provides a rich variety of ecological habitats, supporting many native plant species.

The Northern California Coast region encompasses:

• The Coastal Lowlands ecoregion contains beaches, dunes, and marine terraces below 400 feet in elevation. Wet forests, lakes, estuarine marshes, and tea-colored streams are characteristic features of the landscape.
• The low mountains of the Northern Franciscan Redwood Forest ecoregion lie entirely in the coastal fog zone and are characteristically covered by fog-dependent coast redwoods and Douglas-fir.
• King Range/Mattole Basin ecoregion, which includes a mixed evergreen forest of Douglas-fir, tanoak, and madrone, as well as areas of grassland. Prairies and coastal scrub cover many of the headlands.
• The Coastal Franciscan Redwood Forest ecoregion extends through Mendocino County from just south of King Range to just south of the Russian River in Sonoma County. This central redwood forest is more of a mixture of conifers and hardwoods. Vegetation includes a multi-story canopy of redwood, Douglas-fir, tanoak, bigleaf maple, evergreen shrubs, and various grasses.
• The Fort Bragg/Fort Ross Terraces ecoregion forms an elevated coastal plain.
• The Point Reyes/Farallon Islands ecoregion includes the Point Reyes Peninsula, Bodega Head, the sand spit at the north end of Bodega Bay, and the offshore Farallon Islands.
• The Santa Cruz Mountains ecoregion covers the western and southwestern parts of the range where vegetation includes redwood, Douglas-fir, tanoak, coast live oak, and California bay, along with some chaparral and coastal scrub species.
• The San Mateo Coastal Hills ecoregion with coastal scrub vegetation and a few small areas of cropland. Marine terraces, coastal benches, and small valleys are the primary landforms.

The climate in the North Coast Ecoregion is dominated by the marine influence of the Pacific Ocean. Temperatures average between 50-55ºF. Summer daytime temperatures are often modified by fog and sea breezes. Precipitation ranges from 40 to 100 inches. The growing season lasts 250 to 310 days.

The Northern California Coast region lies in Climate Zones 4, 7, 15, and 17.

Six counties make up the North Coast Ecoregion: Del Norte, Humboldt, Mendocino, Sonoma, San Mateo, and Santa Cruz Counties. The largest towns are Crescent City, Eureka, Arcata, and Fort Bragg.

According to the U.S. Forest Service, Invasive species have contributed to the decline of 42% of U.S. endangered and threatened species, and 18% of U.S. endangered or threatened species. Invasive species compete directly with native species for moisture, sunlight, nutrients, and space. They displace and alter native plant communities, degrade wildlife habitat and water quality, and potentially lead to increased soil erosion.

The federal government has estimated that nearly 25 percent of the 20,000 plant species native to North America are at risk of extinction, many of these through habitat loss. You can help reverse this trend by planting great native plants in your garden.

A plant is considered native if it has occurred naturally in a particular region or ecosystem without human introduction. There are many benefits to growing native plants.

• First, these plants are better adapted to soils, moisture, and weather than exotic plants that evolved in other parts of the world. They need fewer fertilizers, and pesticides or use less water.
• Second, they are unlikely to escape and become invasive, destroying natural habitats.
• Third, they support wildlife, providing shelter and food for native birds and insects, while exotic plants do not.

Here is a list of California native trees that are well-suited for plantings in shady gardens of the Northern California Coast Region.

• Never collect native plants from the wild as it will deplete natural ecosystems. 
• When possible, plant species grown straight from local seed sources. These native originals are the best choice, as they co-evolved with specific wildlife, which supports migration, breeding, and other seasonal interdependencies.