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Wednesday, December 24, 2014

Pinus attenuata - Knobcone Pine

The Knobcone Pine is a California native conifer closely related to the Monterey Pine and will hybridize in overlapping native stands. Often seen as a single stemmed tree, one of the most obvious features to me is its commonly seen multi-stemmed habit. The trees prefer poor sandy soils and will likely reach 30-50' tall. The most recognizable features are the clusters of long lasting cones and groves of all the same age due to their dependance on fire to open the cones.

Leaves are evergreen, needle shaped, 3 needles per cluster, medium green or yellowish green, straight or twisted, slender but stiff, lasting 4-5 years, 3-1/2 to 6" long.

Stems reddish brown, not thick, not thin.

Long terminal bud, most likely going to develop female cones.

Cones 4-6" long, in whorls of 4-5, conical but asymmetrical, yellowish brown, hard, and heavy. The scales are tipped with prickles that are long on the tops of the cone but do not elongate on the cone side closest to the stem. Cones very persistent and do not open without the heat of fire. (Other closed cone pines do open with high heat after some years). 

You can see the color, the pitch, and the asymmetrical shape. You can also see the shape of the scales at the top of the cone, larger, verses the ones on the lower edge, more compressed. While the picture below is too close to the branch, you can also get a sense of how many cones are produced in one area.

Here is somewhat of a close up of the scales with hooks.

Bark is thin, brown to gray, with thin fissures showing some reddish color.

Pinus radiata for sure. They are both 3 needle pines, with variable color leaves and asymmetrical cones, though these have cones that remain on the tree forever, and have pointed hooks on the ends of the scales. The growth habit is also very different.

Other 3 needle pines in our area:
P. attenuata, Knobcone Pine is native to the northern county and can be seen in UCSC wild areas. Cones are very different, in large clusters on the main stems and held for years.
P. canariensis, much longer softer needles, longer cones, much fuller habit but more or less the same overall shape but way full.
P. coulteri, longer bluer leaves, more stiff and dont seem to droop on the stems, not as restricted to the ends of the branches as they last 3-4 years. Much broader habit. There are some around.
P. jefferyi, the cones are different in that the prickle on the scale is curved inward and will not stick you and you will not likely see one in SC.
P. radiata,  dark green leaves, shorter and softer cones without curved hooks.

There was one at Cabrillo, but it came down. 

Santa Cruz
Empire Grade at the enter section with Felton Empire Rd and Ice Cream Grade. Actually they are all along Empire Grade well past UCSC.

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