Eagle Project: Removing Tamarisk from the San Gabriel River

The project of habitat restoration will consist of the removal of the invasive plant tamarisk from the East Fork of the San Gabriel River.  It will also include the planting of trees within the campsite. The Forest service defines invasive plants as “non-native plants whose introduction does, or is likely to, cause economic or environmental harm or harm to human health.”  

Tamarisk can usually out-compete native plants for water. A single, large tamarisk can transpire up to 300 gallons of water per day. In many areas where watercourses are small or intermittent and tamarisk has taken hold, it can severely limit the available water, or even dry up a water source.

Tamarisk can grow in salty soil because it can eliminate excess salt from the tips of its leaves. When the leaves are shed, this salt increases the salinity of the soil, further reducing the ability of native plants to compete.

Because of its ability to spread, its hardiness, its high water consumption, and its tendency to increase the salinity of the soil around it, the tamarisk has often completely displaced native plants in wetland areas. From a wildlife point of view, the tamarisk has little value and is usually considered detrimental to native animals. The leaves, twigs and seeds are extremely low in nutrients, and, as a result, very few insects or wildlife will use them. In one study along the lower Colorado River, tamarisk stands supported less than 1% of the winter bird life that would be found in a native plant stand. Because of the tamarisk's ability to eliminate competition and form single-species thickets, wildlife populations have dropped dramatically. Tamarisk is difficult to eradicate. It grows back readily after cutting or burning. Research and many programs are now in place to reduce or eradicate tamarisk, and laws are being enacted to eliminate its sale and importation. At Death Valley National Park, it was found that, when tamarisk was eradicated and native species allowed to grow, water returned to wetland areas and wildlife again thrived.

• Train Scouts to remove plants.
• Set up easy ups, water station and first aid station. Go over all safety rules with Scouts and adults.
• The next step is to go over safe handling of tools and assign adults to observe and mentor Scouts. I will then break Scouts into groups of 3 and make sure that all Scout are properly hydrated and have applied sunscreen.  
• Assign each group to three types of assignments, digging out seedlings and disposing, trimming large plants of seeds and disposing, digging out of large plants. Older Scouts will remove larger plants. Younger Scouts will trim seeds and dig up seedlings.
• Mr. Walsh, with the help of other adults, will treat plants with U.S. Forestry-approved herbicide too large to dig out. We will take a ten minute break every hour and make sure that Scouts hydrate.
• Take younger Scouts to where trees will be planted and plant trees.
• At campfire I will discuss the day with Scouts and talk about how much their service means to the their community and how thankful I am that they helped me with their project. Let Scouts talk about what they felt the experience meant to them.

For many years, we have helped tear down dams on the San Gabriel River that were built my miners panning for gold. These dams have stopped native fish from traveling to their spawning grounds. We have also helped pick up trash along the river left by picnicers.

But the worst danger to the river are these non-native plants. They could literally stop the flow of water down stream by clogging the river bed. This would leave no water for fish, animals, birds and insects. This would also stop the flow of water to aquifers downstream. Many people and animals rely on this water source for drinking water. We feel that those who benefit from the San Gabriel River should help protect the river. And that is what we want to do.