Exploring potential trade-offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in Southern California
In Southern California cities, urban trees play a vital role in alleviating heat waves through shade provision and evaporative cooling. Trees in arid to semi-arid regions may rely on irrigation, which is often the first municipal water use to be restricted during drought, causing further drought str...
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| Format: | Article |
| Language: | English |
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Frontiers Media S.A.
2024-03-01
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| Series: | Frontiers in Climate |
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| Online Access: | https://www.frontiersin.org/articles/10.3389/fclim.2024.1280615/full |
| _version_ | 1797242879791333376 |
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| author | Rachel Torres Christina L. Tague Joseph P. McFadden |
| author_facet | Rachel Torres Christina L. Tague Joseph P. McFadden |
| author_sort | Rachel Torres |
| collection | DOAJ |
| description | In Southern California cities, urban trees play a vital role in alleviating heat waves through shade provision and evaporative cooling. Trees in arid to semi-arid regions may rely on irrigation, which is often the first municipal water use to be restricted during drought, causing further drought stress. Finding a balance between efficient water use and maintaining tree health will be crucial for long-term urban forestry and water resources management, as climate change will increase drought and extreme heat events. This study aimed to quantify how urban tree water and carbon fluxes are affected by irrigation reductions, and how that relationship changes with tree species and temperature. We used an ecohydrologic model that mechanistically simulates water, carbon, and energy cycling, parameterized for 5 common tree species in a semi-arid urban area. We simulated a range of irrigation reductions based on average outdoor water use data from the city for a recent extreme drought as well as with warmer temperatures. We then analyzed the response of model outcomes of plant carbon fluxes, leaf area index (LAI), and water use. Results show that reducing irrigation up to 25%, a comparable amount as the California state mandate in 2014, has minimal effects on tree primary productivity and water use efficiency. We found that transpiration was linearly related to irrigation input, which could lead to a short-term loss of evaporative cooling with irrigation reductions during drought. However, primary productivity and LAI had a nonlinear response to irrigation, indicating shade provision could be maintained throughout drought with partial irrigation reductions. Results varied across tree species, with some species showing greater sensitivity of productivity to both irrigation reductions and potentially warmer droughts. These results have implications for water resources management before and during drought, and for urban tree climate adaptation to future drought. |
| first_indexed | 2024-04-24T18:46:14Z |
| format | Article |
| id | doaj.art-5b41cf14b3dd43b487270ccc96e33c81 |
| institution | Directory Open Access Journal |
| issn | 2624-9553 |
| language | English |
| last_indexed | 2024-04-24T18:46:14Z |
| publishDate | 2024-03-01 |
| publisher | Frontiers Media S.A. |
| record_format | Article |
| series | Frontiers in Climate |
| spelling | doaj.art-5b41cf14b3dd43b487270ccc96e33c812024-03-27T05:12:13ZengFrontiers Media S.A.Frontiers in Climate2624-95532024-03-01610.3389/fclim.2024.12806151280615Exploring potential trade-offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in Southern CaliforniaRachel Torres0Christina L. Tague1Joseph P. McFadden2Bren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA, United StatesBren School of Environmental Science and Management, University of California, Santa Barbara, Santa Barbara, CA, United StatesDepartment of Geography, University of California, Santa Barbara, Santa Barbara, CA, United StatesIn Southern California cities, urban trees play a vital role in alleviating heat waves through shade provision and evaporative cooling. Trees in arid to semi-arid regions may rely on irrigation, which is often the first municipal water use to be restricted during drought, causing further drought stress. Finding a balance between efficient water use and maintaining tree health will be crucial for long-term urban forestry and water resources management, as climate change will increase drought and extreme heat events. This study aimed to quantify how urban tree water and carbon fluxes are affected by irrigation reductions, and how that relationship changes with tree species and temperature. We used an ecohydrologic model that mechanistically simulates water, carbon, and energy cycling, parameterized for 5 common tree species in a semi-arid urban area. We simulated a range of irrigation reductions based on average outdoor water use data from the city for a recent extreme drought as well as with warmer temperatures. We then analyzed the response of model outcomes of plant carbon fluxes, leaf area index (LAI), and water use. Results show that reducing irrigation up to 25%, a comparable amount as the California state mandate in 2014, has minimal effects on tree primary productivity and water use efficiency. We found that transpiration was linearly related to irrigation input, which could lead to a short-term loss of evaporative cooling with irrigation reductions during drought. However, primary productivity and LAI had a nonlinear response to irrigation, indicating shade provision could be maintained throughout drought with partial irrigation reductions. Results varied across tree species, with some species showing greater sensitivity of productivity to both irrigation reductions and potentially warmer droughts. These results have implications for water resources management before and during drought, and for urban tree climate adaptation to future drought.https://www.frontiersin.org/articles/10.3389/fclim.2024.1280615/fullecohydrologyurban water useecosystem servicesurban forestrywater conservationdrought resilience |
| spellingShingle | Rachel Torres Christina L. Tague Joseph P. McFadden Exploring potential trade-offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in Southern California Frontiers in Climate ecohydrology urban water use ecosystem services urban forestry water conservation drought resilience |
| title | Exploring potential trade-offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in Southern California |
| title_full | Exploring potential trade-offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in Southern California |
| title_fullStr | Exploring potential trade-offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in Southern California |
| title_full_unstemmed | Exploring potential trade-offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in Southern California |
| title_short | Exploring potential trade-offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in Southern California |
| title_sort | exploring potential trade offs in outdoor water use reductions and urban tree ecosystem services during an extreme drought in southern california |
| topic | ecohydrology urban water use ecosystem services urban forestry water conservation drought resilience |
| url | https://www.frontiersin.org/articles/10.3389/fclim.2024.1280615/full |
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