Meet Our Community Collaborators: Monica C.

MONICA C.

Community Programs Specialist, Chino Basin Water Conservation District

Monica works for our Operation Smart Water project which aims to find ways to efficiently use water for plant life during time of water droughts, while also studying how watering plants can work with and against environmental factors to provide air cooling effects.

Monica photographed leading a community event with gardeners

What is your role in Operation Smart Water (OSW)? /

I am supporting the team with community engagement on the Huerta del Valle Community Gardens Project. My role allows me to assist with the design and implementation of garden meetings, research, and the water conservation practices.

Why did you want to participate in OSW? 

It is important to our team that we are supporting the project’s reach to the community. Assuring that the project is practical, applicable and replicable for both participating gardeners, and fellow garden members who will learn from them. I am involved to make sure the research serves their needs and that the whole community can benefit from the resources we are able to provide while at the same time coming to sound conclusions.

What has been your favorite experience with the project so far? 

My favorite part of the project is the opportunity to bring new ways to assess water usage in community gardens and provide resources to help gardeners become more water wise. Often, as they mentioned, gardeners are told about the strategies for water conservation but then don’t have access to the materials to implement those strategies.

What do you see as the most valuable aspect of the work you’re doing with OSW? 

I believe community gardens are such an integral part of urban resiliency. They provide autonomy in food production, cooling places, green space, access to the outdoors and habitat. I am excited to be part of a project that takes one aspect—water—and works with the community members to learn more and create change.

Any anecdotes from time spent on the project? 

Huerta del Valle is such a bustling place. It is a joy to visit. There are always families there, the co-op is selling produce and every time we hold a meeting there, someone makes lemongrass and honey tea that is delicious and restorative. It was quite impressive to hear the participating gardeners narrow down all the aspects of gardening they wanted to research. While they finally settled on creating a research project around water usage methods, they also discussed the importance of knowing your soil and how water can help control pests and plagues. There is so much the gardeners could research and I am glad they are as interested as we are in the results.

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Water Usage vs. Tree Growth: The Ecological Trade-Off of Urban Trees in Southern California

By Peter Ibsen, Ph.D. Candidate; Department of Botany and Plant Science, University of California Riverside

For the past several years, I have taught ecology classes to hundreds of undergraduate students at University of California Riverside and have found that the urban tree is an ideal common ground to discuss the ecological concept of “trade-offs.” You see, every single student has experiences with urban trees, from backyard lemons, to tire swings, to taking a nap in the shade of a sycamore on a hot day. Urban trees provide all these services and so many more, yet, the future of urban trees in dry regions is in doubt, and we, as urban residents, have to make serious considerations about ecological trade-offs between water usage and tree growth.

With the assistance of hundreds of citizen scientists, I am conducting a study of urban tree function across the climate gradient of Southern California. My early results find that the urban forest comprises a broad spectrum of ecological strategies regarding tree growth and water usage. It is possible to find species exhibiting all combinations of “fast/slow” growth and “liberal/conservative” water usage.

Figure 1. Ten species of urban trees oriented in an ecological trait space. Each quadrant represents a growth-to-water use strategy. Trees are represented using the US Forest Service IDs by species.

However, my research has discovered two very important trade-offs of water use and tree growth. When separating out the urban trees found in coastal southern California from those found in desert regions, what appears is an interesting difference between the two communities. The desert urban forest exhibits functions of a faster growth and liberal water usage. This goes against some conventional thinking that people plant more water-conserving trees in the desert. They key finding here is that trees and parks are heavily irrigated, and as long as a species can withstand the heat, they can take advantage of both the water and abundant sunlight for growth.

Figure 2: The effects of irrigation in Palm Springs. The difference between the irrigated Desert Highland Park and the natural Palm Springs environment on the right highlights this effect.

I also studied how individual species may change functional strategies when planted from the coast to the desert. By measuring the difference of plant water pressure before dawn (when plants have low water pressure) and in the middle of the day (when plant have higher water pressure), I am able to calculate the water status of a species at a certain location. A higher water status implies that the tree is losing more water to the environment. I discovered that all species studied, save one, increase their water usage when moving from a coastal environment to a desert one.

Figure 3: The differences in water status of California urban tree species. Most species exhibit an increase in water status when they are planted in the urban desert.

When taking all these results together, there is a clear management trade-off. In hotter and more arid environments, urban trees have the potential to experience faster growth at the expense of increased water usage. For urban stakeholders, this is serious consideration. Faster growth means quicker establishment of shade and greater cooling of air temperature. However, increased water usage has serious consequences for an area prone to extended droughts. As the future Southern California climate is predicted to become hotter and drier, our results highlight the uncertainty of our urban forest. My research will continue to add more species to the study, with a goal of both higher resolution of results, and ultimately an idea of which species might be “the right trees, for the right place, in the right time.”

And, thank you to all the community scientists who helped find the trees included in my study, including partners across the Greater Los Angeles region! Please let me know if you have any questions.