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  •  science >> Ciência >  >> Biologia
    LA precisa de 90.000 árvores para combater o calor extremo. Os moradores se mobilizarão para plantá-los?

    Crédito:Domínio Público CC0

    Em 2019, o prefeito Eric Garcetti revelou um plano ambicioso para plantar 90.000 árvores em Los Angeles até 2021 como parte do Green New Deal de Los Angeles.
    Para conseguir isso, ele nomeou a primeira oficial florestal da cidade, Rachel Malarich, para chefiar a Divisão de Florestas Urbanas e autorizou uma rede de organizações sem fins lucrativos e "embaixadores da comunidade" para ajudar e incentivar os moradores a plantar árvores tão necessárias.

    Mas mais de um ano após o prazo de Garcetti, descobriu-se que plantar árvores em Los Angeles é muito mais difícil do que parece – principalmente quando se trata de atingir os bairros que mais precisam de cobertura de árvores.

    Com pouco mais de 65.000 árvores plantadas até hoje, as autoridades estão descobrindo que sua dependência dos moradores da cidade para plantar e cuidar das árvores vem com limitações significativas:moradores de bairros mais pobres que não possuem terras podem ter dificuldade para plantar árvores ou eles encontram problemas para cuidar de novas árvores durante sua fase crítica de estabelecimento de três anos.

    Em algumas áreas – como o dossel estéril no centro da cidade – as novas árvores são frequentemente destruídas por veículos ou vândalos antes que possam amadurecer, enquanto as árvores mais antigas são cortadas por desenvolvedores de novos edifícios ou equipes de transporte que buscam limpar as linhas de visão nos cruzamentos.

    Mas esta não é a primeira vez que L.A. lança um plantio de árvores em grande escala e, no entanto, enfrenta obstáculos. Em 2006, o prefeito de Los Angeles, Antonio Villaraigosa, lançou um programa para plantar 1 milhão de árvores, junto com Nova York e Xangai. Mas em abril de 2013, a cidade havia plantado pouco mais de 400.000.

    Desta vez, Malarich disse que está mais preocupada com o aspecto patrimonial das árvores e onde elas estão sendo plantadas do que com o número. Ela observa também que a promessa de Garcetti incluiu a promessa de aumentar o dossel das árvores da cidade em pelo menos 50% em áreas de baixa renda até 2028.

    “A quantidade de proteções que estamos fornecendo através do aumento da cobertura do dossel é mais importante do que o número de árvores”, disse Malarich.

    As árvores fornecem inúmeros benefícios para os moradores de Angelenos, incluindo a captura de escoamento de águas pluviais e reabastecimento de águas subterrâneas, limpeza do ar e melhoria da saúde mental. Os pesquisadores também descobriram que bairros com poucas árvores e muito pavimento, grandes edifícios e outras superfícies absorventes de calor podem ser 10 graus mais quentes do que as áreas circundantes.

    Mesmo com as restrições históricas da seca, os especialistas enfatizaram a importância de continuar a regar as árvores e mantê-las vivas. Durante a última seca, até 14.000 árvores nos parques de Los Angeles – cerca de 4% do total – podem ter morrido.

    As restrições à seca implementadas em 1º de junho pelo Departamento de Água e Energia de Los Angeles incluem uma exceção para a rega manual de árvores e não devem ter um efeito adverso na saúde das árvores se forem seguidas corretamente, disseram especialistas.

    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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