Knobcone Pine Along with the Coast Redwoods and Douglas Firs that grow in the hills around Scotts Valley grows another native conifer, the Knobcone pine, Pinus attenuata. Knobcone pines tend to grow in drier chaparral-type sites such as that above the Randall Morgan Preserve off of Geyer Road. According to Frank Perry, Research Associate, Santa Cruz Museum of Natural History, the Knobcone pines, Bishop pines and Monterey pines “belong to an informal taxonomic category known as the California closed-cone pines. In most species of pine, a set of cones matures annually, opening and dropping their seeds in the fall. With the closed-cone pines, however, many of the cones remain sealed with resin and attached to the branches. In the case of the Knobcone Pine, the cones can remain closed for decades. Monterey Pine cones may open after a few years, but remain on the tree. This “closed-cone” characteristic is known as serotiny which most botanists believe evolved as an adaptation to dry climates interspersed with periodic forest fires. Again according to Perry, “The heat from fires sweeping through the crowns of the trees causes the resin seal to melt. In as little as a day after the fire, the cones open, at once releasing a seed supply saved up from multiple years. Although the burned mature trees usually die, many new trees soon sprout from the seeds, recolonizing the area more quickly than other tree species.” Serotiny of itself makes sense in terms of the trees’ survival – when the seeds are released after a fire, they fall to bare mineral soil fertilized by the fire and cleared of a thick layer of duff that would otherwise keep the seedlings roots from penetrating the soil. Knobcone cones will stay closed even after the tree dies, the seeds remaining viable for up to 60 years just waiting patiently for that next blaze! It is thought that in Central California fires, when not suppressed, formerly occurred once every 65 years in coastal drainages, and once every 30 to 35 years inland. The last fire to pass from Zayante to Scotts Valley occurred in 1929 thus making the current stands of Knobcone pine long overdue for a reproductive occurrence. Unfortunately local Knobcone pine woodlands are so overgrown that what should be a ground fire passing through the area could now rapidly turn into a conflagration threatening the nearby communities; so manual clearance followed by a controlled burn would be necessary to maintain the woodlands.
Posted on: Fri, 18 Jul 2014 17:20:28 +0000
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