Gorse

- mid 1800s: introduced as a hedge plant and as forage [source]

Gorse was introduced into Marin County 100 years ago from Ireland. The Irish traditionally planted gorse on the graves of their dead and brought this tradition with them to "The New World". [source]

- before 1894: Gorse was introduced to the West Coast [source]

- By the 1950s gorse had spread throughout western Washington and Oregon and northern California. It has been reported in every coastal county in California from Santa Cruz to Del Norte.

-Seeds are impermeable to water, preventing immediate germination. They may remain dormant yet viable in the soil up to thirty years, with reports of up to seventy years (Zabkiewicz 1976).

-Heat stimulates germination, particularly at temperatures reached just below the soil surface during fire.

1983: the San Mateo County Department of Parks and Recreation manually removed dense gorse from San Bruno Mountain, a task requiring approximately 350 person-hours per acre. [source]

-Gorse seeds are too heavy to be dispersed by wind, and usually fall within six feet of the parent plant. Seeds may be spread by ants, quail, water, and human activity. [source]

July 2010: Invasive Species and Fire in California Ecosystems

-------

Gorse has long been cultivated for its use as a hedge, Native to central and western Europe

Seeds are too heavy to be transported by wind-- are carried by animals such as ants and quail, and by water. They are very small, impermeable to water so do not germinate right away, but can remain viable for 30 years, and in some reports up to 70. Germination, under suitable conditions, can happen at any point within the year. "Heat stimulates germination, particularly at temperatures reached just below the soil surface during fire."

"Like many species of gorse, it is often a fire-climax plant, which readily catches fire but re-grows from the roots after the fire; the seeds are also adapted to germinate after slight scorching by fire."-wikipedia

FIRE ECOLOGY OR ADAPTATIONS: (http://www.fs.fed.us/database/feis/plants/shrub/uleeur/all.html)

Fire adaptations: Gorse is referred to as a "pyrophytic" (fire-loving) species in its native range [25,65].Gorse responds to fire by sprouting from the basal stem region (coppicing) and by establishing from soil-stored seed [5,42,74,92,98,99]. Postfire regeneration of gorse can be prolific and rapid [42,80,82].

Gorse is ranked by the California Invasive Pest Plant Council as one of the most widespread and invasive wildland pest plants that displaces natives and disrupts natural habitats

Gorse is difficult to control because adult plants sprout from the stem and root crown following damage to aboveground parts, and because it establishes a large seed bank from which numerous seedlings establish, especially after disturbance.

A legume, gorse is a nitrogen-fixing plant. As such, it outcompetes native plants.

On San Bruno mountain, the insurgence of gorse has meant a loss in grassland habitat.

Gorse is exceedingly flammable because volatile oils are concentrated in the spiny foliage and branches. (http://firesafemendocino.org/wp-content/uploads/2014/05/Controlling-the-Spread-of-Gorse.pdf)

gorse video:

http://www.opb.org/television/programs/ofg/segment/the-gorse-attack/

cal-ipc factsheet:

http://www.cal-ipc.org/paf/site/paf/442

San Bruno Mt gorse report:

https://parks.smcgov.org/sites/parks.smcgov.org/files/documents/files/San%20Bruno%20Mountain%20Gorse%20Control%20Project.pdf