- Author: Janet S Hartin
To date, over 2,000 climate-ready shade trees and tips on their planting and long-term care have been provided by UC Master Gardeners and over 20 partners to residents of low shade neighborhoods in San Bernardino and Riverside Counties through the “Trees for Tomorrow Start Today” project. Tree species given away are identified from research projects including the joint University of California/United States Forest Service (USFS) study at UC Riverside as well as from other research, local observations, and input from the green industry and academic colleagues.
Why is this project so important? 95% of Californians now reside in cities and suburban environments. Resulting urban heat islands created by built environments coupled with impacts of climate change can be mitigated through nature-based solutions. Planting climate-ready shade trees now will help ensure cooler urban areas in the next several decades as trees mature and maximize their urban ecosystem benefits. Fortunately, the shade from a single well-placed tree can decrease surface temperatures of black asphalt and artificial turf by more than 70 degrees F in hot inland and desert cities. Studies show that surrounding air temperatures can also be reduced through the transpiration process.
A major goal of the"Trees for Tomorrow Start Today" project is to enhance tree canopy cover in low shade neighborhoods also plagued with much higher than average levels of air pollution and pulmonary and cardiovascular disease incidence. Events over the past month have occurred in Fontana, San Bernardino, and the Salton Sea.
Thank you to all our partners and, especially, our tree recipients, for greening and cooling your yard and neighborhood! 
- Author: Janet Hartin
Applications Now Being Accepted for the University of California Cooperative Extension Master Gardener Program “Trees for Tomorrow Start Today” Project.
University of California Cooperative Extension (UCCE) San Bernardino County is currently recruiting adults (18 and over) who are interested in becoming volunteers for our "Trees for Tomorrow" project. Complete training is provided online through a 50-hour Master Gardener training class taught by subject matter experts. Master Gardener volunteers will provide research-based information on the selection and care of heat, drought, and pest resistant trees and help our non-profit partners and community leaders enhance tree canopy cover in our most vulnerable neighborhoods. (To date, we are proud to have partnered with the Inland Empire Resource Conservation District, CA Climate Action Fellows and many non-profit organizations, communities, ESRI, and others to give away over 600 trees in the last year!)
Applications to become a UCCE Master Gardener volunteer for this project are open through August 31, 2022. UCCE Master Gardener “Trees for Tomorrow” Volunteer Application link: http://ucanr.edu/u.cfm?id=287
Questions about the application process or the volunteer opportunity? Contact UCCE Area Environmental Horticulturist Janet Hartin at jshartin@ucanr.edu
Why volunteer for this project? We are facing unprecedented times due to climate change and urban heat islands increasing temperatures in our communities. One of the solutions to a "cooler, greener, tomorrow" is through tree planting and proper selection and long-term care of heat, drought, and pest resistant trees.
Why trees? Shade produced by a single tree can reduce surface temperatures of asphalt and other impervious surfaces by up to 65 degrees F. Trees also lower air temperatures; enhance pollinator and wildlife habitat; absorb pollutants; reduce energy use and related costs (homes, offices, vehicles); beautify neighborhoods; absorb and store carbon dioxide; and provide many other ecosystem and societal benefits.
You can make a difference like never before enhancing tree canopy cover in our neighborhoods. Do you want to learn more about what UCCE Master Gardeners do for San Bernardino County residents and communities, find out what upcoming events they are hosting, or have them answer your horticulture questions Here's your pot of gold: https://mgsb.ucanr.edu/
We are looking forward to hearing from you!
- Author: Janet Hartin
Our population of urban trees is shrinking! You can help turn this around by protecting your own trees and by planting new ones recommended for your climate and the conditions around your home. For more on this topic, please revisit my February blog for specific selection and care recommendations: https://ucanr.edu/b/~ZuB.
In addition, please encourage your city to plant a wide range of recommended species today for a healthier tomorrow. Why is this so important? Many of our current street trees are in the 11th hour of their lifespans. While some that were planted decades ago are simply aging naturally, in other cases, they are perishing prematurely due to poor selection and care. This leads to a downward spiral; trees not adapted to the climate they're planted in and not receiving proper care are much more susceptible to invasive pests (shot-hole borers, etc.) and diseases than are healthy, well- chosen and maintained trees. Even the loss of one front yard shade tree can significantly reduce shade, increase the surrounding temperature, and diminish energy savings.
Another reason we're losing our trees is due to the negative impacts of urban heat islands (UHIs) which shorten the lifespan of many species of trees dramatically. Some trees (even many natives!) just aren't able to withstand the higher temperatures (sometimes exceeding 20 degrees) they are subjected to due to UHIs.
What are urban heat islands and why should we care? Urban heat islands are caused by reradiated heat from paved concrete and (especially) asphalt surfaces. 
And, our cities are growing and expanding. Very few Southern California residents reside in rural areas. Instead of living near pastures, field-filled crops, and forests that cool the surrounding area through evapotranspiration, the vast majority of us reside in warmer urban city centers. Conditions we expect our city trees to endure in 2021 are very different from even 20 to 30 years alone, let alone decades ago.
The good news is that, through proper tree selection and care, we can be a part of the solution. In fact, trees offer many benefits that offset the impacts of UHIs. Cities with larger tree canopies are a testament to this fact and have fewer adverse impacts from UHIs than do cities with low tree canopies. Trees reduce the impact of UHIs by shading parking lots, buildings, and vehicles), deflecting the sun's radiation, and cooling the atmosphere through evapotranspiration. Trees also absorb and store carbon which lessens the impacts of pollution from fossil fuels. A well-tended mature landscape tree can absorb 40 tons of carbon over its lifespan.
The solution? Augment our current urban tree palettes with heat, drought, and pest-resistant native and adapted non-native species. A case in point of a native tree in trouble is our beautiful Joshua trees (Yucca brevifolia) which are dying off in their namesake National Park and seeding 500 or more feet higher elevation than parent plants. Planting trees that withstand UHIs today is crucial for tomorrow.
We are well on the way to identifying landscape tree species that can remain healthy under adverse urban conditions. In our UC ANR/United States Forest Service study examining the performance of 12 species of underplanted but promising landscape trees at UC Riverside, several candidates are standing out for their heat, drought, and pest resistance. Examples include "Bubba" Desert Willow (Chilopsis linearis "Bubba:), "Maverick" Thornless Honey Mesquite Prosopis glandulosa), and "Red Push" pistache (Pistacia x "Red Push").
- Author: Janet Hartin
