When the Audet family turns on the lights at Blue Farm, they are using electricity that comes from cows—cow manure (粪肥), to be specific.

Cows produce a lot of wastes. One cow can create 30 gallons of wastes each day. Now imagine the output of over 1,000 cows at Blue Farm. That’s really a big amount.

When farmers clean their barns, they put the wastes in a big heap, and spread some of them on their fields for fertilizer. But now places like Blue Spruce Farm have a new way of using cow wastes. They use them to produce electricity.

Here’s how it works: A big machine moves back and forth cleaning the barn floor. “The cows aren’t bothered,” says Marie Audet. “They are animals of habit; they get used to it, and just lift one foot and then another to let it go by.”

The machine pushes the manure into a big 600-gallon tank like a small swimming pool. The tank is called a digester (化粪池) because what happens there is just like what happens inside a cow: Bacteria get to work and continue to digest the manure.

Methane gas (甲烷、沼气)in the atmosphere is known as a “greenhouse” gas because it keeps heat just like a greenhouse does, causing our planet to warm up. That’s an environmental concern. But the digester has a good result. Its gas is kept and used to power electric generators (发电机).

At Blue Farm, the generators make enough electricity to power 400 homes. The Audet family sells the extra electricity they can’t use themselves.

There are patches of green taking root in European cities. It is part of a popular movement that started in Asia to clean the air, cool down temperatures, and improve the quality of life of city residents.

This movement began in India with Indian eco- entrepreneur Shubhendu Sharma who was inspired by the tiny forests in Japan created by Akira Miyawak, a botanist who saw this as a solution to regenerate the land. In 2014, Sharma gave a Ted Talk about how valuable the mini ecosystems he was planting across India are. Sharma planted them anywhere he could, near schools, factories, and houses. These mini ecosystems grow ten times faster than conventional forests and are considerably more biodiverse.

Now, Europeans are following his example and tiny forests are springing up across the continent. But first, Europeans had to adapt his methods to the different soil conditions, species and climate, while taking into account the effects of climate change. “Species growing here are more likely to do well and be able to adapt to climate change,” said Belgian biologist Nicolas. “So, I contacted scholars and tree nurseries to identify suitable native tree species and locally sourced materials to improve the soil.”

The first tiny forest was planted in the UK in 2020 in a programme run by ecologist Victor Beumer for Earth-watch. He said that the organization plans to collect data about biodiversity and carbon sequestration (碳封存) so that the environmental influence of the forests can be tracked in the long term. There are 17 of these forests now and 21 will be planted by 2022. These mini forests are seen as an asset that can help residents weather heat waves, improve water retention, remove carbon from the air, and the best benefit.

While these European forests are still relatively young and the full impact of them on the environment is still unknown, one thing is a given. Bringing more nature into cities will have a positive impact on the life of urban residents. Being in nature is good for your health, and wellbeing.