The Polyphagous Shot Hole Borer (PSHB) and plant disease known as Fusarium dieback persist within the Shipley Nature Center, Huntington Central Park and throughout Orange County. This past year approximately 60% of our older trees went down as a reuslt of the effects of the PSHB and the region’s five-year drought.
There are no effective treatments to stop the disease at this time. Bark spraying, injecting chemicals, mechanical removal and solarization slow down the spread. Chemicals cannot be used because our pond is a natural aquifer. There are few species of native trees currently showing resistance. Several different arborists have been into the nature center in the past year to assess the trees and provide advice.
John Kabashima, Ph.D. retired University of California Agriculture and Natural Resources, spoke to a group of us about the PSHB and then looked at our trees. The Friends of Shipley Nature Center continue to manage the PSHB beetle-fungus complex within the nature center through implementation of the Shot Hole Borer Maintenance Plan. In addition, we currently have a relationship with a local arborist who is available to plan and act as needed.
Rounds are made daily by our Groundskeeper and others who have been trained to ID any new problems. Always look up when walking in along wooded areas and report any concerns to the front office. The symptoms of sick trees are easy to ID once demonstrated to observers. Read more: http://sustainability.uci.edu/wp-content/uploads/sites/5/2015/04/PSHB-Symptoms-and-Lookalikes.pdf
Reforestation efforts are underway with the goal of replacing the tree canopy lost with a diverse range of species selected based on potential resistance to PSHB.
Mother Nature is very busy these days.
The trees in this grove are Coast Live Oaks (Quercus agrifolia). These trees were planted when Shipley Nature Center was started about 40 years ago. During our restoration period the grove was enlarged and now you will see many Coast Live Oaks as you walk along the trail toward the Redwood Forest.
Coast Live Oaks are evergreen. New leaves form and the old ones fall off so the tree is never without leaves. In spring, blossoms are formed which look like clusters of small tassels, when they are pollinated they form acorns. In autumn, the acorns drop to the ground to provide food for our resident squirrels, and to provide seedlings to replenish the grove. The Native Americans who lived in the regions where these trees grew used acorns as staples for their diet.
Look up in the canopy. The crowns of the trees form a broad shade cover. Notice the structure of the trees, a gray super structure of gnarled limbs and branches which make the trees quite distinctive
At present, you will see two large Oaks lying on their side with a portion of their roots exposed. These trees fell at different times a few years apart. Wind and our high water table were factors. New growth is present in both trees, a testament to the will to survive, and as an example of how a forest changes over time. Coast Live Oaks commonly live more than 250 years.Next Habitat »: 1 2 3 4 5 6 7 8