TreeMapLA is an ambitious collaboration of nonprofits, local governments, businesses – and you – to map the urban forests and watersheds of Greater Los Angeles. By adding information about LA’s trees and watershed solutions, and updating their needs, we create a powerful tool to learn about and care for our urban ecosystem and its value, including specific environmental and economic benefits. For more information on TreeMapLA, visit our About page.
This video, which walks you through how to map a tree, is a good place to start.
Beyond that, there are several ways that you can explore and use TreeMapLA.
From school children to professionals, everyone can play a part in making TreeMapLA a vital resource. This is a big project: there are hundreds of thousands of trees in Greater Los Angeles. But the more complete we can make TreeMapLA, the more useful it will be. You can contribute to a powerful tool for helping us understand – and manage – the forest that shades, shelters, feeds, and provides clean air and water for the people, birds and wildlife of our city. TreeMapLA can help open our eyes to the value of trees and watershed solutions to the environment and the economy, which can lead to protecting the ones we have, and planting and caring for new trees and installing more watershed solutions.
To get you started, please use this detailed list of Common Trees of Los Angeles.
If you don’t know the tree species, you can use the Urban Tree Key, a comprehensive and easy-to-use tree identification tool featuring 250 species common to urban areas all across California. Still not sure? Leave that field blank—but add a photo, so that one of our expert Tree Nerds can help identify the species!
Entering the circumference of a tree is crucial for helping track that tree’s growth and environmental benefits. Measure the circumference of the trunk at a height of 4.5 feet (52 inches) from the ground, and enter the measurement in the Circumference field. The website will automatically calculate the Diameter. For complicated situations like trees with bumps or forked trunks, watch this in-depth video.
We love you and all of your foibles—plus, only people under age 18 can reliably cite the difference. Circumference is the measurement all the way around a circular object, in this case the trunk of the tree. Diameter is the measurement through the center of the circle. We don’t want you to cut the trees down to measure them and we would never ask you to perform calculations that require using π—because, remember: we love you.
This video will take you through the ins and outs (and ups and downs) of measuring the height of your tree.
Marking Empty Planting Sites (dirt areas along the sidewalk where a tree once was) on the map allows us to see where new trees are needed most! To add an Empty Planting Site to the map, simply go through the normal “Add a Tree” process without entering any species information and in Step 3, the entry should be listed as “Empty Planting Site.” But make sure you add the Plot information and whether there are powerlines overhead, to help us Urban Forestry folks to choose the best species for that location. Once you have mapped these sites, you can use Advanced Search to see where other Empty Planting Sites are.
Adding a Tree Alert or recording your Tree Stewardship to a tree record allows you to share your tree experience with the rest of the TreeMapLA users. Tree Alerts let other users know to take notice of a tree, whether it needs help (“Needs Water”) or it’s just busy being extra beautiful (“In Bloom Now”). Tree Stewardship actions are TreeMapLA’s version of a humble-brag. This is where you can let the world know what a wonderful human being you are (“I watered this tree”). NBD. Add an Alert or an Action on the Tree Info Page for any tree. You can also search by any Alert or Action, using Advanced Search. For a visual guide to Tree Alerts, use this handy Tree Alert Guide.
Planting location refers to the location where the tree is planted. This information helps to give us a better idea of possible environmental factors affecting the tree. Please select the location that most accurately reflects your tree's situation:
We haven’t forgotten about previous mapping technologies like paper and pencil! You can print out our Manual Mapping Sheet to jot down tree details while you’re out in the field (probably best when coupled with a printed map of the area).
Absolutely! TreeMapLA supports the addition of information for trees in all of Los Angeles County. Outside of LA County, you’re on your own, pilgrim.
YES! If your city, community or agency has a tree inventory you would like to add to TreeMapLA, please contact TreeMapLA@treepeople.org.
We know—to err is human! But currently, we’re just going to have to live with our mistakes, because the ability to edit and delete Watershed Solutions is still being worked out. So, for right now, don’t hit “Done” unless you really mean it!
TreeMapLA can tell you where the trees in your neighborhood are, but when you want to put in new trees, you can visit our Resources page to learn how to properly plant and care for your trees to help fill in the city's forest!
We’re excited you’re excited to get your neighborhood’s trees on the map! Check out this Group Mapping Toolkit to learn how to rally the troops and get your map on! (Note: Cold beers optional but recommended.)
Drop us a line at TreeMapLA@treepeople.org and we'll connect you to the right people.
We would love to have your contribution. Please drop us a line at TreeMapLA@treepeople.org and let us know your thoughts. If you just want to make use of the data, download it from the map results. You can also access the code, which is open source, via Github.
Well, the term open-source means a lot of things to a lot of people, but here we mean it as widely as possible: the data, the software source code, and the website html/css code are licensed under the GNU General Public License (GPL) copyright terms. They are all freely available to anyone. All that is required is that you agree to follow the terms of the GPL license. For more information, visit the GNU website. You can download the source code from Github.
Most of our early data will come from people like you, adding one tree at a time. In the near future, we hope to upload data sets from local authorities and community groups.
You can help us ensure that the data is as current and accurate as possible by updating and correcting information on the trees in your neighborhood. We have implemented a number of checks that will hopefully prevent the entering of incorrect data. If you find incorrect information, please correct it!
To be honest, we're not sure yet, but as time goes by and we gather more data, we'll come back to assess the quality. In the mean time, we feel like we're on pretty solid ground, considering recent studies about the reliability of Wikipedia and the rise of Citizen Science.
A common misconception! Los Angeles County is mostly a Mediterranean climate, except for parts of the Antelope Valley, which are the western tip of the Mojave desert. Deserts are defined as having 4” of rain annually or less. Here in Los Angeles we average 12 to 15”. Mediterranean Climates have long, hot, dry summers and short, cool, wet winters. During those long, hot, dry summers, trees cool our cities (reducing our energy use), shade the ground (decreasing water evaporation from the soil and prolonging the life of asphalt, reducing a city’s cost for repaving) and shade cars, thus reducing VOCs (volatile organic compounds). In winter, trees conserve rainwater, by slowing it down and allowing it to soak into the ground. A tree saves more water than it takes to get it established. And if that doesn’t do it for you, check out the other great benefits of trees.
Trees are especially important during the drought, for all of the reasons outlined above! And in times of drought, our city's trees need our help. When we cut down on watering our landscapes, our trees suffer. A tree may look healthy, but without regular watering, it can become stressed and die. Look around your neighborhood: stressed trees are everywhere: dry and sparse leaf coverage, dead and dying branches. When it comes to sharing our water, trees should be our priority! For information on how to keep your trees alive and healthy during the drought, take a look at this helpful infographic.
The eternal debate: is it a big shrub or a small tree? Sometimes it is both! Many larger shrubs that can be pruned to a single trunk have been included. We had to draw the line somewhere, but wanted to include trees and shrubs large enough to make a significant contribution and watch those eco benefits add up.
It's true that palms are not trees, because they lack secondary growth (branches) and cambium cells that grow a new layer of wood every year (the tree rings seen in a cross section of a tree's trunk). They belong to the group of flowering plants called monocots (grasses, palms, onions). They, along with other large monocots (giant yucca and dragon tree) are a part of our urban landscape and contribute their benefits, although often much less so than a tree with the same trunk diameter.
Reporting an issue on a potentially hazardous or dead tree on TreeMapLA is NOT a way of communicating that issue to any municipal agencies. TreeMapLA is a collaborative mapping tool and inventory of trees in the greater Los Angeles region. The “Alerts” function is solely for the purpose of motivating users to take personal responsibility for LA’s Urban Forest and provide basic tree care for those trees in need. If you are concerned about a public tree, please contact your local government.
Our environment, when it's functioning well, provides many services that are critical to human health and survival. This is especially true of trees in cities. Some of the services that the trees around us provide include filtering pollutants out of the air and water, reducing energy use, sequestering carbon, and creating oxygen. When we understand and value these services, we can better manage – and increase – the trees that surround us. To learn other benefits of trees click here.
To calculate the eco impact of a tree, the i-Tree software we use must know the species and diameter of the tree. For many of the trees, we might know the location of the tree but not the exact species and diameter. For this reason, many neighborhoods in Los Angeles may show lots of trees but not list any eco impact data. You can help us more accurately calculate eco data by entering the species and diameter for trees in your neighborhood.
We calculated the economic benefits and environmental impacts of the trees using the i-Tree software provided by the USDA Forest Service’s Urban Ecosystems and Processes team. This software provides options for calculating benefits by assigning a dollar value to the impact of trees in a number of ecological areas. These areas include electricity, natural gas, carbon dioxide, particulate matter, nitrogen dioxide, sulfur dioxide, volatile organic compounds, and stormwater interception. The USDA Forest Service provides default dollar values for each of the categories in i-Tree. We used these default values for the Southern California Coast region for all of the aforementioned fields except electricity and natural gas. For the electricity fields, we used a price of $0.1323 per Kwh based on local Los Angeles electricity rates for residential customers. For natural gas rates, we used a price of $1.50 per therm.