. Sky Trailhead is located within an unburned Coastal Scrub community. Douglas fir, pine, various scrub plant species, and shrubs inhabit the unburned section of the forest. Due to fire suppression policies in this area, pines grow older than usual and dwarf mistletoe (Genus Arceuthobium) is able to attack larger sized trees. Older, larger trees also show more heart rot. This coastal forest has an infrequent and high severity fire regime due to wet conditions, so the fire regime is climate limited rather than fuel limited. The infrequent fire regime allows for surface and ladder fuel accumulation. Tomales Bay State Park encompasses an unburned bishop pine forest. This area consists of old unburned bishop pine trees. The bark beetle genus Ips …show more content…
The area has numerous dense clusters of small bishop pine trees. Bishop pines (Pinus muricata) are fire adapted and have serotinous cones. Before the 1995 Vision Fire, Bishop pine was low in abundance. Following the fire, the species experienced an 85% increase on the landscape, replacing other tree species, and expanding at the expense of Douglas fir, which experienced a 50% decrease following the fire. Blue blossom ceanothus (Ceanothus thyrsiflorus) is prevalent in the area due to its lasting seed bank, and experienced a 4000% increase following the fire. Trees not directly killed by the fire were more susceptible to bark beetles invasions due to fire stress. Red turpentine beetle (Dendroctonus valens), a parasitic beetle that adds additional stress to trees, experienced an outbreak following the fire. Ips plastographus followed red turpentine beetles and caused widespread mortality of bishop pine trees. This is why there are no older bishop pine trees on the landscape. There are still large standing Douglas fir trees on the landscape because no beetles in the region attack Douglas …show more content…
Blue blossom ceanothus (Ceanothus thyrsiflorus) reestablishes due to its lasting seed bank. Cues following fire trigger germination of these seeds. Blue blossom ceanothus can bank seeds for up to 100 years. The seed bank that established after the 1995 Vision Fire had likely been deposited by a former post-fire population (Forrestel, Moritz, & Stephens, 2011). An infrequent, high severity fire regime would favor blue blossom ceanothus, because it allows the species to bank seeds during periods with low fire activity, and then to germinate from the seed bank following a high severity fire. Bishop pines (Pinus muricata) are fire adapted and have serotinous cones; the closed cones open following fire and the seeds are able to take advantage of the abundant resources, such as additional light due to open canopy. A high severity fire regime would favor Bishop pines because the species needs high severity fires to release seeds, and can successfully outcompete other species post-fire due to this reestablishing strategy. Coyote brush (Baccharis pilularis) is a shrub that has moderate fire tolerance. Fires often do not cause mortality and the plant can resprout from the roots. In coastal scrub communities, fire also allows coyote brush to reestablish from seeds and outcompete other vegetation due to open canopies and exposed mineral soil. Fire suppression in coastal scrub communities allows shade tolerant species to outcompete coyote brush so a more frequent fire regime would