Madrone Ecology
The lone madrone is a beautiful sight, but more often than not one finds them in a community mixed with other trees, shrubs and herbaceous plants. These plant "alliances", "associations" and "groups" replicate themselves across the landscape depending on aspect towards the predominant sun direction, topography, elevation, underlying soils, proximity to saltwater, and human tending of the ecosystem to name a few. Unfortunately, some of these associations are increasingly uncommon, ranked by NatureServe as vulnerable or imperiled - noted below. These forest communities are named by dominant, co-dominant or characteristically present plant species often labeled in tiers. The dashes (-) in the names separate species in the same canopy layer; slashes (/) separate species in different canopy layers.
Madrone communities in the species range
Salish Sea/Georgia Straight in British Columbia & Puget Trough in Washington
Arbutus / hairy manzanita - vulnerable
Pacific Madrone - Lodgepole Pine / Salal Forest
Southern Vancouverian Dry Douglas-fir - Madrone Woodland
Douglas-fir-Pacific madrone Woodland
Douglas-fir - Pacific Madrone / Oceanspray Forest - critically imperiled
Pacific Madrone - (Douglas-fir) / Salal Forest
North Pacific Maritime Dry-Mesic Douglas-fir-Western Hemlock Forest
Douglas-fir - Grand Fir - Pacific Madrone Forest & Woodland
Willamatte Valley-Klamath-Siskiyou
Cascadian Oregon White Oak - Conifer Forest & Woodland
Oregon White Oak - Ponderosa Pine - Douglas-fir Forest & Woodland Group
Tanoak - Pacific Madrone Forest Alliance
Pacific Madrone - Douglas-fir - Oak species / Pacific Poison-oak Woodland - vulnerable
Southern Cascades-OR/CA Coast Range
Californian Moist Coastal Mixed Evergreen Forest
Douglas-fir - Tanoak - Pacific Madrone Forest Group
Bishop Pine - Pacific Madrone / California Huckleberry Forest - imperiled
Pacific Madrone Alliance Mixed evergreen forest, Tanoak; Northern mixed evergreen forest; Montane hardwood forest
Sierra Nevada
Pacific Madrone Woodland/Forest Alliance with tanoak, canyon live oak, interior live oak, California black oak, and bay laurel
Douglas fir-Pacific madrone @Salish Sea
Oregon white oak-Pacific madrone @Willamette Valley/Klamath-Siskiyou
redwood- Pacific madrone @Coast Range of California
The larger environment and landscape history influences the type of plant community one finds.
Environment: Common in close proximity to salt water on Western edge of North America. Isolated patches inland in mountains. In Southern range found in ravines. Generally doesn't tolerate extremes of heat or cold.
Topography and Aspect: Can be found on gentle to steep slopes, "sunny slopes" and ridge crests of bedrock hills. Hillsides and rocky knolls with dry, generally southern exposures. In Southern range found on north facing slopes.
Soils: Sites can be shedding and dry, colluvial veneers/residuum over bedrock. Soils are described as shallow, rubbly, very fine (sometimes glacial) sands to medium textured-gravelly (glacial outwash and till) soils and well drained. Due to these conditions, soil moisture regime is very xeric to subxeric. Often described as "nutrient-poor ."
Shade tolerance: Moderate
Vegetation: Rarely dominant, generally co-dominant, "subordinate" or diagnostic of unique plant communities that are relatively drought tolerant. Herb layer may poorly develop.
Disturbance/Succession: In the pre-colonial landscape, a moderate-severity fire regime likely prevailed across the species range with variable severity and intermediate frequency. Coastal development has resulted in widespread loss, fragementation and alteration of madrone ecosystems. Wildfire may benefit madrones by clearing pathogens and removing encroaching vegetation, such as Douglas-fir. See more on Better Management Practices.
Biodiversity notes: Berries provide forage for birds in the fall and into winter. Tendency for heart rot is favorable for cavity nesting birds and other animals. Can be browsed heavily by deer.
The wide-spreading root system is associated with ericoid mycorrhiza. The fungus is characterized by “coils” that form in the epidermal cells of the fine hair roots of ericaceous species. The fungi colonize the root cells and establish hyphal networks around the roots, providing increased water and nutrient absorption while the plant in turn provides the fungus with carbohydrates through photosynthesis.
Ericoid mycorrhizal fungi also have hydrolytic and oxidative enzymes that are important in mobilizing nutrients from organic matter and leaf litter. This is a big reason for madrone’s ability to persist through drought and thrive in relatively harsh conditions such as rocky bluffs or soils we may characterize as "nutrient deficient."
There has also been investigation into the symbiotic associations between the madrone soil community and links to nearby Douglas-fir that may assist with disease resistance in madrone.
Madrone superpower: lignotuber. Where the base of the stem meets the ground is a woody swelling of the root crown. A more vague term is "burl." It can be more pronounced in some trees more than others. This portion of the tree contains dromant buds and stores carbohydrates and nutrients necessary for bud development that supports growth and where new stems can sprout vegetatively. This reproductive strategy has commonly evolved in perennial shrubs of Mediterranean-type ecosystems. Thousands of meristematic foci may be present. Similar to stem cells, undifferentiated cells and tissue are capable of growing and changing into new shoots in response to fire or other damage. This is what allows the trees to "resprout" or replace stems that have been lost.
Madrone flowers are fragrant and show up as large drooping clusters referred to as panicles of small, white, urn-shaped flowers. "Urn"= resembles an upside down rounded vase. The species has both male and female organs; the plant is self-fertile.
Flowering period: starts in April and ends by June across the species range
calyx is 5-parted surrounding the urn-shaped, united petals | petals are 6-7 mm long | ovary superior | 10 stamens with pilose filaments near the base | anthers are awned from the back to near the tip, and open by terminal slitlike pores
Bees are the principle pollinator though flies and ants are attracted to the nectar. If you are lucky you might see a hummingbird visiting the flowers.
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