{"id":37968,"date":"2024-05-31T18:45:05","date_gmt":"2024-05-31T17:45:05","guid":{"rendered":"https:\/\/greencitysolutions.de\/?p=37968"},"modified":"2026-10-19T00:47:02","modified_gmt":"2026-10-18T23:47:02","slug":"healthy-greenery-in-the-city","status":"publish","type":"post","link":"https:\/\/greencitysolutions.de\/en\/healthy-greenery-in-the-city\/","title":{"rendered":"(Healthy) Greenery in the City?"},"content":{"rendered":"

“Nature Must Be at the Heart of Our Cities”<\/em><\/strong><\/a><\/p><\/h3><\/div>

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Cities are undoubtedly the habitat of the future: by 2030, two-thirds of the world’s population is expected to live in urban areas<\/a>. However, they are also the main driver of global warming and the places “where the fight for a green recovery will be won or lost”<\/a>, as they consume 78% of the world’s energy and produce more than 60% of greenhouse gas emissions, according to UN Habitat<\/strong><\/em><\/a>.<\/p>\n

We agree with the WWF<\/em><\/strong><\/a> that “nature must be at the heart of our cities”<\/a>. Urban areas are particularly vulnerable to the effects of climate change: “Globally, 80% of cities face extreme climate-related events”<\/a>.<\/p>\n<\/div>

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Photo: Benjamin from Unsplash<\/p>\n<\/div>

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More Green in the City?!<\/strong><\/h5>\n

Unfortunately, increasing soil sealing and densification make it challenging to plant more desirable greenery to bind emissions at the source and mitigate heating. Planting trees in urban areas is becoming increasingly difficult. The soil is often sealed, crisscrossed with cables, or tunneled, making it unsuitable for tree planting.<\/p>\n

To ensure newly planted trees thrive, adequate root space, water, air, and light must be available. Many tree species grow in nurseries for about 8-10 years before being transplanted into cities, where they take several more years to develop large, shade-providing canopies. Some of the “well-known ecosystem services of trees [come] into play only in older stages”<\/a>.<\/p>\n

A stately street tree, about 20 years old, is estimated to be worth around \u20ac66,000. A newly planted street tree costs approximately \u20ac5,000. Many trees in our cities are so stressed by extreme weather, pests, and vandalism that they have to be felled prematurely. In numerous cities, replanting targets are not met due to a lack of suitable spaces. There are mainly two major problems with compensation or replanting: finding the right location and the necessary funds for expensive young trees<\/a>, as “a young tree indeed costs a lot of money: four-figure amounts are incurred in the first years”<\/a>.<\/p>\n

As reported by Deutschlandfunk<\/a> <\/strong><\/em>, several factors contribute to the threat to the tree population:<\/p>\n

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  1. Climate Change: The warmer it gets, the harder it is for trees. More trees in the city would also protect the tree population itself. For new plantings, robust climate trees that can better withstand heat and low water levels are now being chosen.<\/a><\/li>\n
  2. Globalization: New pests arrive that plants and trees often cannot adapt to quickly enough.<\/li>\n
  3. Human Activity: Trees are still being felled to make space for new housing or commercial properties.<\/li>\n<\/ol>\n<\/div>
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    Photo: Sylas Boesten from Unsplash<\/p>\n<\/div>

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    “Native” Green in the City?<\/strong><\/h5>\n

    Furthermore, existing urban greenery suffers greatly, especially “native trees are increasingly struggling”<\/a> in terms of both care and selection of new plantings<\/a>. Vibration and fine dust pollution from traffic, space constraints due to compacted soil and various pipelines, road salt, and damage from vehicles or construction work all take their toll<\/a>. They suffer from climate change with “water shortages and long dry periods”<\/a>, losing substance and resilience. “Valuable old trees are particularly affected by damage following extreme weather phenomena in 2017, 2018, 2019, and 2020”.<\/a> Since the extreme drought and heat periods, there have been “unprecedented levels”<\/a> of dying trees, according to the “Park Damage Report<\/strong><\/em><\/a>” by the Technical University (TU) of Berlin<\/strong><\/em><\/a>, funded by the German Federal Environmental Foundation (Deutsche Bundesstiftung Umwelt, DBU)<\/em><\/strong><\/a>. It documented “branch breaks, collapses, and uprootings of individual trees”<\/a>, as well as “die-offs of entire groups and stands of trees”.<\/a> In Berlin’s Sch\u00f6nhausen Palace Park, “there are no healthy trees left”<\/a>.<\/p>\n

    The continuous temperature records, the “hottest months on record”<\/a>, and overall climate change are “taking an increasing toll on trees”<\/a>, both young and old. The Park Damage Report clearly notes “a deterioration of the situation for trees in recent years”<\/a>: “59% of all trees are in poor condition”<\/a>, and “damaged trees have been found in all parks<\/a>“. The MDR<\/em><\/strong><\/a> recently headlined the “Forest Condition Report for 2023” (\u201eWaldzustandsberichts f\u00fcr 2023\u201c<\/em><\/strong><\/a>),” presented by Agriculture Minister Cem \u00d6zdemir, with “Only one in five trees in Germany is healthy”<\/a>.<\/p>\n

    In Berlin, the BUND Berlin<\/em><\/strong><\/a> stated in 2021 that “the condition of Berlin’s street trees has continued to deteriorate”<\/a>, calling it a “creeping environmental disaster”<\/a>, which an analysis by the Senate Department confirmed: “more than every second tree is damaged”<\/a>. Even a tree considered “a tree of the future”<\/a> and “a robust city tree”<\/a> 15 years ago, such as the ash tree<\/a>, is now facing issues due to a fungus introduced from China<\/a>.<\/p>\n<\/div>

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    Photos: Susanne Schilp<\/a>, J\u00fcrgen Runo \/ City of Braunschweig<\/a>
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    However, it is not only extreme heat, insufficient water, and improper care<\/a> that are stressing city trees. In winter, W\u00fcrzburg’s garden department warned of falling branches and toppling trees due to existing snow loads<\/a>. The age of the trees or park usage<\/a> also contribute to their poor condition. City trees are increasingly stressed by heat and drought, with urban temperatures 5-8 degrees higher than in forests<\/a>, causing them to evaporate more water. This additional water demand cannot be met due to soil sealing. The “extremely dense soil”<\/a> also means “no room for extensive root systems”<\/a>. New pests exacerbated by climate change also contribute to faster tree aging: “Street trees often only live for 60 years”<\/a>.<\/p>\n

    Young trees planted to positively impact the urban climate also face challenges<\/a>. It has been observed that young trees tend to die more often near busy streets<\/a>, not only due to climate change but especially due to “vibrations caused by traffic” that further compact the soil and damage fine roots<\/a>. Vienna also reports issues with harmful salt use at public transport stops in winter<\/a>.<\/p>\n

    Alarmingly, “the overall health of plants is declining<\/a>“. Some municipalities face “an almost unsolvable task”<\/a>.<\/p>\n<\/div>

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    Photos: Henry Perks from Unsplash, Statista<\/a>
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    The Solution?<\/strong><\/h5>\n

    Alternatives are needed. In the future, criteria for future trees will be sought based on “growth strength, life expectancy, maintenance requirements, resilience, and fracture resistance<\/a>“. “Non-native future tree species, i.e., species favored for climate change in Germany<\/a>“, generally performed better than native species<\/a>, particularly concerning “heat stress and drought”<\/a>. “In general, the greater the biological diversity, the more resilient the forest is, the more resistant it is to pests and diseases<\/a>“.<\/p>\n

    However, “exotic” tree species also carry risks, such as (previously) unknown “diseases or pests” or new pollen and allergies<\/em><\/strong><\/a>.<\/p>\n

    The World Economic Forum<\/em> <\/strong><\/a>pointed out that “nature is the most resource-efficient solution for creating resilient, vibrant, and future-proof cities<\/a>“. Examples from around the world show that nature-based solutions can improve the sustainability, resilience, and quality of life in cities cost-effectively and elegantly<\/a> (International Union for Conservation of Nature (IUCN<\/em><\/strong><\/a>). Nature-based solutions in urban areas can “address a wide range of challenges, including climate change, biodiversity loss, disaster risks, water and food security, human health, and socio-economic development<\/a>.”<\/p>\n

    Additionally, a “groundbreaking study”<\/a> by the International Institute for Sustainable Development (IISD<\/em><\/strong><\/a>) in 2021 found that “using nature in infrastructure projects could save $248 billion per year”<\/a>.<\/p>\n

    Research<\/em> <\/strong><\/a>has shown that:<\/p>\n