Torreya californica at King Mountain Open Space
Larkspur CA (Marin County)

September 2012 (400 feet elevation)

by Jim Clark

JIM CLARK wrote (on 11 September 2012) about his personal experience of a well-known Torreya californica wild grove near his home:

For years I have been running a trail at King Mountain Open Space, above the city of Larkspur in Marin County CA. Finally, I noticed a grove of Torreya californica. It is on the north-facing slope at about 400 feet elevation, adjacent to oaks and redwoods.

There are two areas where we found most of the trees. Trees of small to moderate size number in the hundreds, with a few larger trees in both areas. Many seedlings grow along the loop trail and seem to be doing well.

The two largest trees that we found are pictured below. One is a single tree and the other is a cluster of four trees growing from one base trunk (with my wife Natalie for scale). Photos of ripe seeds also shown below.




Jim Clark provided MORE DETAIL (on October 4, 2012):
  • TOPOGRAPHY AND CLIMATE: The grove is growing on a north-facing slope that receives some fog, but not as much as the southern parts of Marin or the west-facing slope of Mt Tamalpais. It is a very moderate climate on that side of the mountain. Other than the trail, there is not much in the way of human impact.

  • LIMITATIONS ON MOVING UPHILL IF CLIMATE WARMS: The grove seems to be located mostly about 200 feet below the top of the mountain, with youngest trees mostly downhill from the older trees, through there are some young trees above the elders, too.

  • ASSOCIATED PLANTS: Most of the trees are growing in three distinct areas that are densely wooded with redwoods and bays. They do better on the ridgeline than in the shaded drainage. Many trees grow in shaded redwood habitat and could be considered spindly. Many are trying to reach canopy height; the larger trees have obtained canopy height. I am not sure what forces help them. Competition between trees for light is a factor because there are so many trees. There are also springs on the mountain. It was logged 120 years ago; second- growth redwoods are abundant and no fires have been in this area the past 100 years.

  • SIZE OF GROVE: The total area is about 4 acres and the total number of trees are more than 100, with many moderate and small trees growing in limited light.

  • SEEDS: I have observed more than 100 seeds lying on the ground undisturbed. Gray and brown squirrels live in this habitat, though I am not sure if any squirrels are actually harvesting the seeds. There are abundant seeds from oaks and laurels, too. Several seeds on the ground still retain their fleshy outer layer; many are falling in September and October. (I am not sure which trees are male or female.)

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