“My dearest Ulmus,” the message began.

“As I was leaving St. Mary’s College today I was struck, not by a branch, but by your radiant beauty. You must get these messages all the time. You’re such an attractive tree.”

This is an excerpt of a letter someone wrote to a green-leaf elm, one of thousands of messages in an ongoing correspondence between the people of Melbourne, Australia, and the city’s trees.

Officials assigned the trees ID numbers and email addresses in 2013 as part of a program designed to make it easier for citizens to report problems like dangerous branches. The “unintended but positive consequence,” as the chair of Melbourne’s Environment Portfolio, Councillor Arron Wood, put it to me in an email, was that people did more than just report issues. They also wrote directly to the trees—everything from banal greetings and questions about current events to love letters and existential dilemmas. “The email interactions reveal the love Melburnians have for our trees,” Wood said.

City officials shared several of the tree emails with me, but redacted the names of senders to respect their privacy.

To: Golden Elm, Tree ID 1037148 21 May 2015 I’m so sorry you're going to die soon. It makes me sad when trucks damage your low hanging branches. Are you as tired of all this construction work as we are?

To: Algerian Oak, Tree ID 1032705 2 February 2015 Dear Algerian oak, Thank you for giving us oxygen. Thank you for being so pretty. I don’t know where I’d be without you to extract my carbon dioxide. (I would probably be in heaven) Stay strong, stand tall amongst the crowd. You are the gift that keeps on giving. We were going to speak about wildlife but don't have enough time and have other priorities unfortunately. Hopefully one day our environment will be our priority.

Some of the messages have come from outside of Melbourne—including this message, written from the perspective of a tree in the United States:

To: Oak, Tree ID 1070546 11 February 2015 How y’all? Just sayin how do. My name is Quercus Alba. Y’all can call me Al. I’m about 350 years old and live on a small farm in N.E. Mississippi, USA. I’m about 80 feet tall, with a trunk girth of about 16 feet. I don't travel much (actually haven’t moved since I was an acorn). I just stand around and provide a perch for local birds and squirrels. Have good day, Al

Melbourne’s email-a-tree service is one in a litany of municipal projects aimed at leveraging personal and institutional technologies to keep cities running smoothly. In Chicago, there’s a text-based pothole tracker. In Honolulu, you can adopt a tsunami siren.