Restoration of Natural Ecosystems  |||  Revegetation Efforts

RESTORATION OF NATURAL ECOSYSTEMS
Parts of the Puente-Chino Hills Wildlife Corridor still have the kind of natural plants, trees, and shrubs that have been growing here for thousands of years. 

Other parts of the hills have been overwhelmed by non-native plant species that were introduced and spread primarily by sheep and cattle ranching over the past couple of hundred years. These non-native plants include the grasses and mustard that are so common today.

Restoration of native plants in local areas is a long-term goal in the Puente-Chino Hills Wildlife Corridor. Native plants resist fire better than non-native ones and provide better habitat for the array of wildlife that are supposed to be here. The non-native plants are like weeds in your vegetable garden. 

REVEGETATION EFFORTS IN THE PUENTE HILLS
By Dr. Cheryl Swift 
Department of Biology 
Whittier College

Baby oaks have been planted. In May of 1999, the Biology Department of Whittier College, together with some residents of La Habra Heights, began work on a project to restore native vegetation on the 25 acre Diaz Property. The Diaz property had been purchased in early 2001 by the Native Habitat Preservation Authority in order to preserve the integrity of the existing wildlife corridor across Harbor Boulevard. The property encompasses north and south facing slopes; once a working avocado ranch, much of the property has been left to weeds.

The first problems that the restoration effort must address are weed control and the establishment of vegetation in the large expanse of cultivated ground on the north facing slope. In an effort to determine the most cost effective way to control the non-native weedy species that had dominated the slope, six plots were established and divided into subplots, which would each receive a different treatment. The various treatments include combinations of mulching, weeding, and seeding. The County Sanitation District donated about 15 tons of green waste for the mulch treatments, and the mulch was spread by a number of individuals including the La Serna High School football team, and a landscape crew donated by Khalid Javaid, the owner of a neighboring property. Several Whittier College students together with citizens of La Habra Heights and Larry Johnson, a native plants landscaper, sampled the vegetated areas immediately to the north of the property boundary in order to establish a list of native species to be used in the revegetation effort. As a result, approximately five acres of the north facing slope were planted with 400 coast live oaks, 400 toyon, and 100 walnuts in early June.

While it is too early in the project to gauge success, to date about 80% of the 900 individual plants have survived and are producing new growth. Whittier College students have marked individual plants and will be monitoring the progress of their growth throughout this first year. Deer, coyote, and several species of hawks are already using the site.

The next phase of restoration has begun on about 3 acres on the south facing slope of the property. Plots have been set out to test other methods of weed control including mulching, application of a commercial herbicide, and the use of plastic to literally "bake" the seeds of weeds to "death."  These plots have been monitored for weed growth and were planted early in the Spring of 2000. They were planted again in the spring of 2001, and further plantings will occur on site. Whittier College students have been collecting seed of walnuts, coast live oaks, purple sage, white sage, toyon, lemonadeberry, and fushia flowered gooseberry as well as a number of other species in Powder Canyon, in order to establish an on-site nursery for plant material from the immediate vicinity. We hope to use this nursery to supply plant material for future restoration efforts.

The students who have worked on the project, Mike Rahe, Talula Wiater, Catie Profeta, and Gilbert Sanchez, are looking forward to seeing a mixed oak-walnut forest where there was once mustard and wild radish, when they return for their 10 year class reunions at Whittier College. As for me, I look forward to sitting in the cool shade provided by the trees we planted, as gray squirrels, scrub jays, and acorn woodpeckers argue over walnuts and acorns. 

Click the link to see photos of the restoration work.