Mia Birk is a particularly committed cyclist even for Portland, a city populated by two-wheel enthusiasts. In seven years as a government official she set in motion many of the projects and reforms that established Portland as a cycling paradise (by US standards). Five years ago, Birk co-founded Alta Bicycle Share, North America’s largest cycle-sharing firm, with Michael Green, which makes her effective co-owner of 14,000 bicycles in nine cities.

And yet the 46-year-old does not see her own transport habits as particularly noteworthy. “I am a completely ordinary person,” she says. “I drive – I have three kids. I ride the bus or the streetcar. I walk. I do all these things – and I bike.”

As a vice president at Alta, Birk works in just about every area of the company’s operations, though she’s best known for her policy advocacy. But her personal habits make her a model customer for the firm’s cycle-share systems. In New York, Washington DC, Chicago, Melbourne and elsewhere, customers pay to borrow the firm’s signature sturdy, step-through cycles from checkout stations. A 24-hour pass in New York costs US$10 (€7); in Melbourne, only AU$2.50 (€1.70). So far, that clientele has logged almost 50 million kilometres aboard Alta bikes – a number set to soar as at least six more systems come into service over the next couple of years. (Seattle is next this autumn, with Toronto and Vancouver in the peloton as well.)

Birk considers casual cyclists like herself as key to that growth. “In five or 10 years, every city of any size will have a bike-share system,” she says. “They will be a totally normal aspect of any transport programme. DC makes a perfect case study. People who live in the suburbs commute to the city by car or train but then use our system to move around the city during the day. Bike-share is that last-mile solution – it adds flexibility to how a person engages with their city.”

Two unusually heavy snowfalls in Tokyo earlier this year had Akira Kobayashi worried. “I wasn’t so concerned about the first one, it was dry and light,” he says. “But the second, was wet and heavy – that’s bad.” Kobayashi, who has the tan and vigour of a man who spends much of his life outdoors, pays close attention to the weather. A certified tree doctor, he looks after the trees in 60 parks and gardens around Tokyo.

Among Kobayashi’s more delicate patients are the city’s famed cherry trees, including thousands of Somei Yoshino, the most popular cherry tree in Japan and Tokyo’s official flower. The cherries bloom to spectacular effect in April but they are fragile trees that need plenty of attention. A cultivated hybrid species developed in the late Edo period, the Somei Yoshino is particularly vulnerable to germs, wind, humidity and fungus.

Kobayashi does what he can to ensure the trees will put on a good show. “The best conditions are a good summer the year before,” he says. “Not too hot or wet, no bugs or fungus and a quiet typhoon season.” He also favours judicious pruning, a matter of debate among sakuramori, or cherry-tree guardians. At Jindai Botanical Garden, where there are nearly 800 cherry trees, Kobayashi is inspecting one of the oldest avenues of Somei Yoshino in Tokyo. The trees are measured and checked for ailments four times a year. Kobayashi puts his ear close to the trunk and uses a wooden hammer to identify rotten parts. He also uses a German instrument called a resistograph, which bores a tiny hole through the tree to identify weak areas.

Kobayashi has been gardening for 40 years, doing everything from designing parks to looking after street trees. There are 2,400 tree doctors across Japan and Tokyo has a tenth of them, but it’s not enough to cope with the number of trees in the sprawling metropolitan area. Kobayashi has set up the new role of “tree checker” – there are now 160 in Tokyo – who can do the basic measure-ments and alert the more specialised tree doctors to potential problems.

Kobayashi loves his trees but isn’t precious about them. He doesn’t even mind that they are used as picnic grounds during the raucous hanami cherry blossom season – “It’s only one or two weeks a year,” he says. “And anyway, it’s good that people are enjoying the trees.”

It’s daybreak in a vacant lot at Toronto’s Evergreen Brick Works, a former brick-making facility turned community environmental centre. Deena DelZotto is checking how her basil leaves are doing. Nearby, Rachel Kimel is hunched over a milk crate, loosening the soil to sow arugula seeds. The duo’s pilot urban-farming initiative, the Bowery Project, is all set to germinate.

The pair, who met while volunteering at a food centre in 2011, came up with the idea for the non-profit project last year after noticing plenty of disused spaces around the city. “We wanted to inject some life into these spaces to make them productive and create something beautiful,” says Kimel. “Although there are a lot of green initiatives out there, there’s nothing like this in Toronto.”

Taking a leaf from Riverpark Farm in New York and Detroit’s urban garden Lafayette Greens, DelZotto and Kimel’s concept is simple: milk crates are filled with soil and compost and converted into a functioning mobile farm that can be put together and dismantled within 24 hours. By persuading property owners to let the Bowery Project operate rent-free, they have managed to keep start-up costs at a modest CA$10,000 (€6,750).

A third of the harvest is sold to local chefs; the rest is split between charities and volunteers. To raise funds and awareness, the project is partnering with the City of Toronto Economic Development and Cultural Department for the summer-long No.9 Eco-Art-Fest, supplying more than 170 crates of pizza toppings, herbs and beer ingredients to festival events. Next year they are setting up farms at the city’s waterfront for the PanAm games.

A number of renowned local chefs such as Order of Canada recipient Jamie Kennedy have already pledged to buy the first fruits.

Less than a decade ago, the Lower Augusta part of São Paulo’s downtown was a drab area with a questionable reputation. Today the quarter has cleaned up its act and is enjoying a second coming as the city’s entertainment district. The revitalisation is mainly due to Facundo Guerra, the Argentinean-born entrepreneur whose venues have been redefining the area, breathing new life into abandoned historic buildings since 2004.

It was then that the former food engineer decided to gather his friends and invest €70,000 in the revamp of a derelict warehouse – the venue that became his first nightclub. Good service and quality drinks in a beautiful and, above all, safe environment began to draw visitors back to the once gritty district. Today Guerra’s diversified property portfolio includes nearby bar Riviera (in partnership with local star chef Alex Atala), the Yacht Club and concert venue Cine Joia.

“I never wanted just another bar, just another nightclub. São Paulo does not need this,” Guerra says of the city that he moved to in 1978. “I want to create original projects that I haven’t seen before here in São Paulo or elsewhere,” adds the 40-year-old who is now spreading to other parts of the city.

In the coming months Guerra will open six new venues in the Bom Retiro neighbourhood, including a cinema, a hotel and a club with resources gathered via crowd-funding.