Earlier this month, I attended the International Urban Forestry Congress in Vancouver, British Columbia. Nearly 800 people from 30 countries participated, and we were blessed with fascinating and useful lectures, engaging panel discussions, exceptional networking opportunities, and an unparalleled “battery charging” opportunity to spend time with colleagues away from our proverbial trenches, sharing our passions for urban forests around our ever-more-connected (for better or worse) tiny blue marble of a planet.

It was good to be reminded that I work within a global research network, and not just an Illinois corporation, nor just a United States nonprofit, nor just a North American charity. This is reflected in our grant-making programs, as a growing number of grants from our other programs have been going abroad in recent years. I know some readers may not consider this a positive trend, since I have had domestic partners challenge me on why they should support us if we are sending money overseas. Regionalism is a strong force among human beings. But trees (and their symbiotic companions and parasitic predators) do not recognize property lines, nor do they hew to municipal borders, nor do they heed state lines, nor do they respect international borders.

Trees are migratory organisms across our ever-changing world, as they slowly and naturally respond to global environmental changes, or rapidly stake out new turf when we select them to line streets and shade homes on continents where nature never would have taken them. And while human preferences and prejudices vary widely from nation to nation, both native and non-native urban trees living in temperate Mediterranean climates like those found in Beirut, Perth, Los Angeles, Rome, Tunis and elsewhere may benefit from exactly the same areas of rigorous scientific inquiry, regardless of where the researchers disclosing it work and live.

I say all this as an older, pragmatic and practical American professional, and not as an inexperienced, pie-in-the-sky Utopian. Trees are a global resource, and tree science is globally relevant, regardless of any of our social, economic, religious or political leanings. My organization is a small player in this planetary network, but we become stronger every time we gather with colleagues from around the world on behalf of the planet’s urban canopies.

Okay, so maybe this Vancouver tree does want some boundaries . . .