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  •  science >> Ciencia >  >> Biología
    LA necesita 90.000 árboles para combatir el calor extremo. ¿Los residentes se animarán a plantarlos?

    Crédito:CC0 Dominio público

    En 2019, el alcalde Eric Garcetti presentó un ambicioso plan para plantar 90 000 árboles en Los Ángeles para 2021 como parte del Green New Deal de Los Ángeles.

    Para lograr esto, nombró a la primera oficial forestal de la ciudad, Rachel Malarich, para encabezar la División de Silvicultura Urbana y autorizó una red de organizaciones sin fines de lucro y "embajadores de la comunidad" para ayudar y alentar a los residentes a plantar los árboles que tanto necesitan.

    Pero más de un año después de la fecha límite de Garcetti, resulta que plantar árboles en Los Ángeles es mucho más difícil de lo que parece, especialmente cuando se trata de enfocarse en los vecindarios que más necesitan cobertura arbórea.

    Con un poco más de 65,000 árboles plantados hasta la fecha, los funcionarios están descubriendo que su dependencia de los residentes de la ciudad para plantar y cuidar los árboles tiene limitaciones significativas:los residentes de los vecindarios más pobres que no poseen terrenos pueden tener dificultades para plantar árboles, o encuentran problemas para cuidar árboles nuevos durante su fase crítica de establecimiento de tres años.

    En algunas áreas, como el centro de la ciudad donde el dosel es estéril, los vehículos o los vándalos suelen destruir los árboles nuevos antes de que puedan madurar, mientras que los desarrolladores de nuevos edificios o los equipos de transporte que buscan despejar las líneas visuales en las intersecciones talan los árboles más viejos.

    Pero esta no es la primera vez que Los Ángeles lanza una plantación de árboles a gran escala y, sin embargo, se encuentra con obstáculos. En 2006, el alcalde de Los Ángeles, Antonio Villaraigosa, lanzó un programa para plantar 1 millón de árboles, junto con la ciudad de Nueva York y Shanghái. Pero en abril de 2013, la ciudad había plantado un poco más de 400 000.

    Esta vez, Malarich dijo que está más preocupada por el aspecto de equidad de los árboles y dónde se plantan que por la cantidad. También señala que el compromiso de Garcetti incluía la promesa de aumentar la copa de los árboles de la ciudad en al menos un 50 % en áreas de bajos ingresos para 2028.

    "La cantidad de protecciones que brindamos a través de una mayor cubierta de dosel es más importante que la cantidad de árboles", dijo Malarich.

    Los árboles brindan innumerables beneficios a los angelinos, incluida la captura de la escorrentía de aguas pluviales y la reposición de las aguas subterráneas, la limpieza del aire y la mejora de la salud mental. Los investigadores también descubrieron que los vecindarios con pocos árboles y mucho pavimento, edificios grandes y otras superficies que absorben el calor pueden ser 10 grados más cálidos que las áreas circundantes.

    Incluso con restricciones históricas de sequía, los expertos han enfatizado la importancia de continuar regando los árboles y mantenerlos vivos. Durante la última sequía, es posible que hayan muerto hasta 14 000 árboles en los parques de Los Ángeles, aproximadamente el 4 % del total.

    The drought restrictions implemented June 1 by the L.A. Department of Water and Power includes an exception for the hand-watering of trees, however, and should not have an adverse effect on tree health if they are followed correctly, experts said.

    As priorities have changed, so have names—Million Trees LA is now called City Plants, a reflection of the emphasis on low canopy areas and maximizing the benefits of trees rather than reaching a specific number. City Plants runs a public-private partnership between the city and six nonprofits to coordinate tree planting and care throughout L.A.

    But to get more trees in the ground, it's imperative to have community buy-in—the city itself doesn't do much planting directly. An estimated 90% of L.A.'s urban forest is on private property, and even street trees are often under the care of the residents who live nearby.

    City Plants will give seven free trees to any L.A. resident to plant in their yard, thanks to funding from the Department of Water and Power. The trees are delivered to homes, along with stakes, ties and fertilizer pellets. City Plants tracks planting locations and monitors the trees' survival for three years—the most vulnerable period of a young tree's life.

    Residents can also request a street tree—one planted in the public right of way—but must sign a Commitment to Water form promising to care for the tree for the first three to five years of its life, which means a deep watering of 10-15 gallons of water once a week by hose or bucket. After the three-year mark, the trees become the responsibility of the Urban Forestry Division.

    In some cases, money from City Plants and state grants from the California Department of Forestry and Fire Protection are able to fund the establishment care for the tree—which includes watering, adjusting stakes and ties and anything else needed to ensure survival in the first three years.

    The next step, however, is to make sure the communities that need trees have access to them.

    The Tree Ambassador program was created last year to develop leaders in historically disadvantaged neighborhoods and assist them in planting and caring for trees in their communities. The inaugural cohort began in September 2021 and ended this April with about 400 trees planted.

    The ambassadors serve as community liaisons to help find residents who are interested in planting trees and communicate the importance of caring for neighborhood trees.

    "The way we structured that program is really to amplify local leader voices," said City Plants executive director Rachel O'Leary. "And many of those local leaders living in neighborhoods that were historically disinvested—wanting to really, honestly, directly compensate them for their community organizing."

    It's a model that not everyone agrees with.

    "They're leaning on nonprofits to get there, they're leaning on homeowners to get to that goal (of 90,000 trees)," said Katherine McNenny, co-founder of Industrial District Green, a nonprofit focused on tree planting downtown. "That's cheating."

    Giving out trees benefits homeowners who live in areas that might not need more trees, rather than a renter in a low-canopy area, especially with the three-year watering commitment, McNenny said.

    "Someone in a low-income community who got a free tree from the city of L.A. a block away … how are they gonna water those trees?" McNenny said.

    Though McNenny appreciates the work done by nonprofits, she believes the city itself needs to doing more direct planting and watering by city employees.

    On a recent sunny Saturday morning that quickly rose to sweltering temperatures, tree ambassador Cristina Velazquez sat at a green table in Koreatown next to buckets of tree saplings.

    Curious locals stopped by to ask—are you really giving away trees for free? How can I get one?

    Though most of the trees were reserved for pickup, some were available for same-day adoption—coast live oaks, Canary Island pines, a crape myrtle with showy summer flowers. Velazquez warned some people to carefully consider how much room they had in their yards, because the oaks would get large.

    "It is a new member of your family," Cristina Basurto, senior community engagement coordinator for the Koreatown Youth and Community Center, told people who came to take their trees home. "When you talk to them, they thrive even more."

    Many people were first-time tree planters and keen on making sure their trees survived. Mulch is good, Basurto advised, but she warned folks against making "mulch volcanoes" around the base of the tree because they can foster too much moisture and cause bark rot. Pomegranates are multi-trunk trees and do particularly well with other pomegranates nearby. And guavas, well you'll have to fight with the squirrels and birds for them.

    Some of the people who came to pick up trees were homeowners, though a few were renters who obtained permission from their landlords or lived in a building with a dedicated gardener.

    City Plants has been holding various tree adoption events around the city, partnering with organizations like the KYCC, Los Angeles Conservation Corps and Tree People.

    "A lot of the open space we have available isn't in the sidewalks; it is in their homes," Basurto said.

    But working with disadvantaged communities also means meeting their immediate needs first. When KYCC goes out and offers trees in the communities it's serving, the biggest problem is often litter, which is how Velazquez got involved with the Tree Ambassador program.

    When the 24-year-old from Westlake moved home after finishing college in 2020, she noticed that her neighborhood was in bad condition "in terms of public hygiene."

    She started a weekly street cleanup group and learned of KYCC, which was planting trees in Westlake and also doing street cleanings. Velazquez said her cleanup group would gather one to two trucks full of litter every week.

    "The next step is the tree," Basurto said.

    While there's always talk of funding for the trees themselves, what's often neglected is money for establishment care, which is why community buy-in is so important, Malarich said.

    One of the partners for the Tree Ambassador program is long-established environmental advocacy group Tree People, which has its own 30-year-old Community Forester Program. Its model also focuses on empowering volunteers to lead tree-planting events in their own communities.

    Tree People currently has a grant to plant 1,000 trees exclusively in the Watts neighborhood and distribute thousands more trees for schools and yards, said Ariel Lew Ai Le Whitson, director of education and community. It's applying for another grant to plant 4,000 trees in South L.A.

    Not everyone is always excited about getting a tree planted in their neighborhood, however. When walking on the sidewalks of L.A., it's easy to see some of the infrastructure damage caused by trees.

    "A resident might have some feelings because a tree was planted there many years ago and maybe messed up their sidewalk," said Eileen Garcia, senior manager of community forestry.

    As tree planting efforts continue, City Plants emphasizes its philosophy of "right tree, right place, right reason" to ensure trees aren't causing further damage in the communities they're placed in, executive director O'Leary said.

    This issue is exacerbated in historically disadvantaged low canopy areas, where you often see parkways that are too narrow for trees, or trees growing in the public right of way.

    Garcia said she hopes to see more funding for more drastic actions such as tearing up large stretches of concrete to create new locations for trees.

    The city is currently undergoing a massive tree inventory of street trees and vacant spots, covering 500 square miles, Malarich said. An arborist will visit every tree in the public right of way and record the species, age and size of the tree. Officials hope to complete the study by next summer, and estimate they will count more than 700,000 trees.

    Malarich is also overseeing an update of the recommended street tree species list, which has to take into account infrastructure and spacing, climate, and the wide range of soil types that can be found around the city.

    But it all comes back to what's important to the community.

    "That's part of what's so complex—we have our expert opinion based on science and data related to tree species but we also have a living piece of infrastructure that people have a strong opinion about," Malarich said.

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