December 2019 home page


Reserving Trees
Darren Smith | Senior Environmental Scientist, California State Parks, San Diego Coast District

Photo Betty Wheeler

Darren Smith on the Torrey Pines State Reserve’s philosophy regarding managing the plant and animal life on the site.

Since Torrey Pines is a State Natural Reserve we support natural ecological processes. We only intervene when there are contemporary human-caused disruptions to these processes. Examples: the introduction of non-native invasive plants, year round flows of water from urban runoff, fragmentation of habitat by urban development, roads, and trails, altered fire regimes, and increased populations of nuisance animals.

We generally leave dead trees standing unless they represent a hazard to visitors or facilities. Dead trees can provide structure for wildlife (for example woodpeckers, raptors, and bluebirds), and habitat for native insects such as boring bees and beetles. It usually takes just a couple of years for these trees to fall over on their own. The California engraver beetle is the main species responsible for the mortality in our Torrey Pines. This beetle persists in living trees. Once a tree’s wood is dry they move on.

We have experimented with watering trees near the lodge with limited success. This is not practical over 1600 acres and over 3000 trees. Also, introducing potable water widely through the reserve could cause damage to other plants and animals. Anywhere an introduced water source is present populations of Argentine ants can colonize. These ants eat native harvester ants (the primary food source for horned lizards) and other wildlife and can carry scale to the root systems of some of our rare chaparral species. There are other repercussions for introducing artificial water especially during warm months when harmful soil pathogens are more likely to develop.

We do intervene a little with Torrey Pine ecology. We trap beetles with a non-toxic trapping system to monitor their population and reduce their numbers. We are also implementing a Climate Ready Reforestation Project to sustain Torrey Pines for as long as possible given the current trend of increased heat and decreasing precipitation.


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