Tecate Cypress: Risky Reproduction

Lauren and Sandra Mardonovich sow Tecate cypress seeds in long pots that provide spacious room for roots.

The Tecate cypress Hesperocyparis forbsiiis a tree found only in Southern California and northern Baja California, Mexico. It has a limited range and is fire dependent, which means the cypress needs fire to reproduce. The cones of this species are serotinous, which means the seeds are released by an ecological trigger (in this case, fire) instead of being released once they reach maturity. When the cones are exposed to heat, the resin that keeps them sealed is melted, the cone opens, and the seed is released. Without fire, the Tecate cypress keeps its seed bank within persistent cones in the tree canopy. When a fire burns a mature stand of Tecate cypress, new seedlings pop up in its place. If this second generation is burned before it reaches maturity, it could wipe out the entire population. There are only four stable populations remaining in California, three of which are in San Diego County. It is because of its limited range and risky reproduction technique that this tree is such a sensitive species.

Tecate cypress cones collected from Otay Mountain await processing.

The Applied Plant Ecology Division at the San Diego Zoo Institute for Conservation Research has partnered with the Nature Conservancy, the Bureau of Land Management, and the California Department of Fish and Game to preserve this unique species. The goal of the project is to provide a safe guard against high-frequency fires wiping out the population.

To do this, we collected enough seed from a mature population to have a portion for safe keeping in the Native Plant Seed Bank at the Safari Park and a portion that could be germinated and planted as a nursery stand. Cones were collected from Otay Mountain and processed at the State of California’s Lewis A. Morgan Reforestation Center. The processed cones resulted in thousands of seeds, and of those, a fraction was planted. From the planted seeds, we are hoping to get 400 to 500 seedlings.

Here's a close-up view of the seeds before being covered with soil.

Once the seedlings have grown to a suitable size, they will be planted at the Rancho Jamul Ecological Reserve. The planted cypress trees will be monitored over the next six months. These trees will be used as a sort of “plantation” where more seeds can be collected as needed in case the other stands burn before reaching sexual maturity.

Lauren Anderson is an intern at the San Diego Zoo Institute for Conservation Research through the Bureau of Land Management’s Seeds of Success Program. Read her previous post, The Desert: Blooms and Hail.