This big bur oak (Quercus macrocarpa) grows on Mountwood Avenue, halfway up the slope of the Niagara Escarpment behind St. Joseph's Healthcare Hamilton's Charlton Campus, one of the city's hospitals.

It's an original tree, meaning it was once part of the original escarpment slope forests at the Head of the Lake, a term that refers to the westernmost point of Lake Ontario and was used by early explorers and pioneers.

You can tell this tree is old because of its deeply furrowed bark and the thick, twisting branches in its crown. I would put it at about 250 years old, so it predates the city.

It's a tree that remembers when much of the tablelands of west Hamilton were prairie and oak savannah. It's a tree that remembers the ancient First Nations trail that ascended the Niagara Escarpment near John Street. It's a tree that would have been a sturdy sapling when First Nations and then, later, early European settlers were using that trail.

Back then, the tree stood in a north-facing, rocky forest surrounded by a rich suite of plants: trees like sugar maple, black maple, butternut, basswood, black walnut, hemlock and red elm; shrubs like elderberry, mountain maple and bladdernut; and flowers like Canada violet, blue cohosh, and small-flowered leaf cup.

Today, it stands in a patch of turf grass surrounded by houses, a parking garage, and a variety of planted, non-native trees and shrubs.

Someone made a choice to save this tree.

It could have been cleared when they built the houses and parking garage. Maybe whoever saved it didn't think much about it. But maybe someone thought to spare the tree, knowing they would never live to see it grow into the craggy old veteran that we get to enjoy today.

We all have a chance to make a similar choice by planting trees that, though we will never live to see them, will one day grow into mature beauties. A bur oak is one such tree.

Oaks are the best pollinator plants in our native flora, and bur oak is a tough, strong tree tolerant of urban growing conditions.

If you are considering planting a tree this spring, plant a bur oak and do your part to build the healthy urban forests of tomorrow.

Paul O'Hara's first book - "A Trail Called Home: Tree Stories from the Golden Horseshoe" - is available for purchase.