Throughout Los Angeles trees are in decline. It is a quiet crisis, and it’s accelerating. Losing trees begins a vicious cycle of creating an ever hotter and drier urban climate that threatens public health and the very livability of our city.
Last spring I attended a presentation by the Urban Forester of Santa Monica. He said that after four years of drought, our trees’ ability to take up water has atrophied, especially in trees not native to our region. Whereas in past years many trees have been struggling but surviving, it’s now reached the point where they’re dying. This is a critical time for saving LA’s trees.
Many of LA’s declining trees need emergency watering. Over the decades taxpayer dollars have paid for millions of trees to be planted in our region, trees that have been repaying us many times over by providing a precious tree canopy. Many of these trees may be lost. This not only means a loss of this investment. It also means a loss of beauty, wildlife habitat, oxygen, air-cleaning, water-cleaning, carbon-absorbing, health-providing services to Angelenos. But even more is at stake: this loss of trees could threaten our very lives.
I learned this vividly on a recent tour of Australia, a country that has seen record-breaking heat in recent years due to climate change. From 1997 to 2010 Australia endured a devastating drought. Their powerful successes, as well as some of their painful mistakes, provide a valuable guide to us in Los Angeles and California as we face similar conditions today.
Like California, Australia responded with progressively deeper conservation measures as their drought worsened. In addition to imposing water use restrictions, government agencies educated the public and engaged communities in taking action. To rapidly increase local water supply, they assisted people in capturing and making use of every drop of rainwater that fell. Agencies provided incentives to install rainwater tanks (also known as cisterns) at homes and businesses. These tanks led people to conserve even more because they became active managers of their visible water “bank account.” The result was a steep drop in per-person water use.
One of the painful lessons from the Australian experience was the loss of millions of trees and public green space, together making their cities hotter and triggering significant public health impacts. There, in neighborhoods that were lacking in trees, people were exceptionally vulnerable to the heat. According to the Centers for Disease Control, excessive heat is a leading cause of preventable, weather-related deaths, particularly among the elderly.
The Australians found that a dense tree canopy can save lives and even in the midst of their own drought, prioritized the planting and care of trees. So, in LA’s drought emergency, what does this mean for us? It means that while we reduce water for non-essential uses, we must use it to keep our city’s trees alive.
A healthy tree canopy and available soil moisture is essential for keeping neighborhoods cool. You can make a difference by learning to water trees properly during the drought. Here are some basic steps to help trees survive:
1. Deeply and slowly water mature trees 1 to 2 times a month with a simple soaker hose or drip system toward the edge of the tree canopy to within 1 foot of the trunk—not at the base of the tree. Use a Hose Faucet Timer (found at hardware stores) to prevent overwatering.
2. Young trees need 15 gallons of water 2 to 4 times a week. Create a small watering basin with a berm of dirt.
3. Shower with a bucket and use that water for your trees as long as it is free of non-biodegradable soaps or shampoos.
4. Do not trim trees during drought, if possible. Pruning and drought both stress your trees.
5. Mulch, Mulch, MULCH! 3 to 4 inches of mulch helps to retain moisture, reducing water needs and protecting your trees. Do not pile the mulch against the trunk.
Call your city government office and register your concern about dying public trees and ask for funds to be prioritized to protect and save our city’s tree canopy.
As voices grow louder in favor of expensive, energy-intensive solutions such as desalination, at TreePeople we firmly believe that simple, quickly deployable solutions are the way to go.
In early 2014, TreePeople implemented a pilot project based on an innovative technique first developed by the City of Melbourne, Australia. The project used standard plastic road barricades (commonly called k-rails or Jersey barriers) that were converted into tree-irrigation pods, or “irricades.” The motivation to use irricades came from the need to quickly use materials many municipalities already have on hand. The irricades hold large amounts of water, and because they
are designed to be portable, they can be delivered directly to drought-stressed trees that are not served by existing irrigation systems.
TreePeople initially deployed five irricades in Coldwater Canyon Park and subsequently partnered with the Los Angeles Department of Recreation and Parks to install 16 irricades in Griffith Park. The pilot projects primarily used common 6-foot barriers, each holding approximately 150 gallons of water. Drip or soaker lines were attached to the outlet at the base of the barriers, which were filled with captured rainwater or recycled water whenever possible, repurposing them into lightweight, portable irrigation pods.
“Preparing, installing and the initial filling of our five barriers at Coldwater Canyon Park took place over two work days. With weekly refills, we began to see results on the targeted, clearly stressed trees in about a month when new buds appeared and leaves filled out even without any rainfall over that same time. The basic concept works well.” – Jim Hardie, Director of Park Operations, TreePeople
TreePeople’s goal was to test the effectiveness of irricades in rehabilitating drought-stressed trees and demonstrate that irricades can be used by municipalities to support urban forests throughout Southern California and beyond.