Sisquoc River Project

Support staff and volunteer expeditions into the San Rafael Wilderness to eradicate tamarisk.

Project Description

Channel Islands Restoration proposes to eradicate non-native invasive Tamarisk species in the Sisquoc River and Manzana Creek. The objective of the project is to restore and maintain habitat for riparian dependent species such as the federally listed arroyo toad, California red-legged frog and steelhead trout. The project is located within the Los Padres National Forest in Santa Barbara County, California on the Sisquoc River system including Manzana Creek and other tributaries. Specifically, the areas treated will be on the main stem of the Sisquoc River and its tributaries including Foresters Leap Canyon, Manzana Creek and its tributaries from the headwaters on the east to the Forest boundary on the west (approximately two miles west of Manzana Camp).

A Few Pertinent Facts about Tamarisk

Tamarisk (also known as salt cedar) is a deciduous shrub or small tree from Eurasia; thus it loses its leaves each year, making it difficult to observe during the period when it has no leaves. Tamarisk has a deep, extensive root system. Mature tamarisk plants are able to reproduce from roots. Flowering branches are mostly primary or secondary branches. Each plant can produce as many as 500,000 seeds annually, and can produce seeds throughout the growing season. High stress induced by fire, drought, herbicides, or cutting can increase flowering and seed production. The seeds are dispersed by wind and water. Seeds are small with a tuft of hair attached to one end enabling them to float long distances by wind and water. Seeds are shortlived and do not form a persistent seed bank. However, they can germinate within 24 hours of dispersal, sometimes while still floating on water. Seeds produced during the summer remain viable for 24 to 45 days. Winter longevity is approximately 130 days. Seed mortality is generally due to desiccation. If seeds are not germinated during the summer that they are dispersed, almost none germinate the following spring (http://www.fs.fed.us/database/feis/plants/tree/tamspp/). Tamarisk trees on floodplains can be difficult to kill, requiring several treatments. The root systems of trees on floodplains are more extensively developed near the ground surface, due to repeated scouring and removal of limbs by floods, and can send up shoots where none existed at the time of initial treatment.