Wed, May 07, 2025 page12

• Environmental Impact Assessment: Why our parks should be messy

  Reducing lawn mowing in parks and leaving leaves where they lay, are part of an approach to noninterference in nature that can have huge environmental benefits

  • By Steven Crook / Contributing reporter
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  Like many hashtags, #NoMowMay is both an inspiration and an oversimplification.

  In the UK — where the movement started — and in those parts of North America where it’s caught on, #NoMowMay urges nature-conscious people to let patches of grass under their control grow wild, so that bees, butterflies and other pollinators can enjoy a temporary habitat and access to food until flowers become abundant at the beginning of summer.

  According to the Web site of Plantlife, a conservation charity that manages 24 nature reserves in the UK, #NoMowMay is “one of the easiest ways to help and connect with wildlife, and the perfect way to start supporting nature in your garden.”

  

  Electric mowers like the one being demonstrated here produce less noise and air pollution than petroleum-burning machines, but fail to answer the question: Should we mow as often as we do?

  Photo: Chen Wen-chan, TaipeiTimes

  Encouraging urban landowners to join the effort, the NGO stresses that even a plot the size of a ping-pong table can help give nature “the best start to summer.”

  LET NATURE TAKE ITS COURSE

  Few Taiwanese have lawns, of course. What’s more, Taiwan’s climate is rather different from Britain’s. Here, several plant species produce flowers (and thus nectar) in fall or winter. But the principle of noninterference, of letting nature take its course, certainly holds lessons for the ways in which the authorities manage parks, curb strips and other public spaces.

  

  Long grass can hinder the growth of saplings, but even where trees are tall there’s a tendency in Taiwan to keep grass short.

  Photo: Steven Crook

  Speaking on condition of anonymity, a contractor for a local government in southern Taiwan says that the grassy areas they look after are usually mown twice a month, because when grass reaches a height of 8cm, “it looks untidy.”

  The contractor says that mowing can help grass grow better. One reason is that it stimulates grass plants to produce more side shoots, creating a thicker lawn. Another is that taller grass is more likely to develop seed heads, which diverts resources from leaf and root growth.

  Seed heads can make a patch of grass look unkempt, but they’re the part of the plant that provides food and shelter to pollinators. They also attract birds who feed on the seeds or the insects that gather around them.

  

  Bags of leaves collected at Tainan’s Pingshi Park await collection and disposal.

  Photo: Steven Crook

  A lawn of uniform height is pleasing to the eye, but research indicates that the opposite is better for biodiversity. Longer grass provides certain species with protection against predators and extreme temperatures, while shorter grass is better for creatures that need to forage or which prefer open areas.

  CRITICS

  #NoMowMay has its critics, and they’re not just individuals who want parks to look like bowling greens. An article republished by Popular Science on May 17 last year asserts that “restoring biodiversity requires more than doing less.” It mentions studies which found that: unmowed plots don’t support significantly more flowers compared to plots where the grass is kept short; that “restored” grasslands have far less plant diversity than landscapes which have never been seriously disturbed; and that, if the goal is getting native wildflowers to establish themselves, rather than simply seed a lawn, it’s best to first kill the grass with herbicide.

  Grass isn’t the only target of overzealous maintenance crews. Particularly in places where people worry about dengue fever, fallen leaves are assiduously removed from parks and sidewalks.

  From an epidemiological perspective, this makes complete sense. Accumulations of leaves can prevent water from draining, and mosquitoes don’t need a lot of water in which to breed — an upturned bottle cap is enough. But if healthy ecosystems are a priority, it’s the wrong approach, according to environmentalist groups such as the Society of Wilderness (SOW, 荒野保護協會).

  In a Nov. 11 Facebook post, SOW argued that, while many people regard leaf litter as trash that should be cleared away, leaves play an important role in park ecology, making a positive contribution to soil health.

  The NGO’s post explained that, as they decompose, leaves increase soil fertility which in turn benefits trees and plants. They protect soil from erosion during heavy rainfall, and slow the rate at which it dries out when the sun is shining.

  They also act as a buffer, ameliorating the problem of soil hardening caused by human trampling. Compacted soil is impermeable to air and water; this undermines the microbial ecosystem and increases runoff.

  The contractor says that, while some people think fallen leaves enhance the landscape, there are others who call the citizens’ service hotline and complain whenever they come across leaf litter.

  “If there are a lot of fallen leaves, it means you’ve not fulfilled your duty of cleaning and maintenance, so you must sweep them up,” they add.

  The use of leaf blowers instead of rakes is especially lamentable, because they injure grasshoppers and crickets while eroding topsoil.

  SOW says if there are so many leaves on a pathway that people may slip, the obvious thing to do is to push them into the flowerbeds. Adding them to a compost pile is another solution. There’s no need to bag them up and send them for disposal elsewhere.

  SOW hopes its supporters can help the public understand that “leaf litter may not look like much, but it’s key to making parks more ecologically diverse and soils healthier.” Transporting and incinerating leaves with household garbage is an unnecessary burden on municipal budgets, the NGO says.

  How much of a burden is hard to say, however. According to the contractor, there are no statistics on the quantity of fallen leaves carted away from public spaces each year. It’s a different matter when it comes to branches collected from parks and roadsides. These have an economic value, as they can be ground into sawdust for mushroom-growing substrate.

  BIOGAS

  Since 2022, the city of Amiens in northern France has shown that incineration and in situ decomposition aren’t the only options when dealing with fallen leaves. The municipality trucks them to a nearby facility where — once plastic, metal and other trash has been removed — they’re degraded in digester vats to create methane-rich biogas. This is then burned in a cogeneration plant that produces both heat and electricity.

  Taiwan is developing biogas infrastructure, but most of what’s been built so far is optimized for manure from pig farms.

  One person who’s expressed the hope that Taiwan’s parks can be a little wilder is Cheng Wan-chi (鄭婉琪). In an opinion piece republished by the Environmental Information Center (環境資訊中心) on July 20, 2021, she argued that, “if we want to bring the concept of ‘natural play’ back to urban green spaces and parks, what needs to be redesigned isn’t the hardware… but the software” — in other words, the management of such places.

  She urged parents to teach their children that earthworms live in soil and that fallen leaves can nourish the land. By designing the right tasks and activities, she added, “parents and children can take care of the land together.”

  Steven Crook, the author or co-author of four books about Taiwan, has been following environmental issues since he arrived in the country in 1991. He drives a hybrid and carries his own chopsticks. The views expressed here are his own.
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