Trees symbolize strength, life, and continuity. They are perfect memorials for those we hold dear or events we wish to remember. As a result, an entire industry is dedicated to planting trees for remembrance.

As clever marketing goes, the concept has been borrowed from the past. Even before avenues of honour started to roll out after World War 1 there were living memorials created with trees. The Duke of Wellington planted oaks to commemorate the Battle of Waterloo and the end of the Napoleonic Wars. Some Aboriginal peoples of Australia planted trees in trees to mark the passing of a loved one. They would plant a tree into the hollow of an existing tree, using the standing tree to provide shelter and protection for the new tree within. It’s hard to say when this practice began, but it is assumed it started over a thousand years ago. But memorial trees aren’t there just to remember loss or sacrifice. The British Royal family commissioned tree plantings to mark births, marriages, and various Jubilees. Happy occasions. Then as dutiful members of the Commonwealth, we also joined in and there is hardly a town in New Zealand that hasn’t got at least one Royal Oak to commemorate one auspicious royal occasion or another. There are memorial trees everywhere and the message is simple, if you want something to stand the test of time, plant a tree.

Putting the reason aside, if you want longevity plant don’t build. Even before the ribbon is cut and the built structure is revealed it has already started to deteriorate. Every day, bit by bit, it dissolves and wears away. Trees on the other hand are alive, they self-repair. Structures crumble, and trees endure. In theory, trees can live forever. The science behind this has to do with DNA replication and telomeres caps, but we’ll save that for another day. Obviously, trees don’t live forever, but they can stick around for quite some time. The oldest living tree is possibly 40,000 years old. And no, it’s not a bristlecone pine, it’s a type of poplar tree (quaking aspen – Populus tremuloides). To put that age into perspective the pyramids of ancient Egypt are a measly 4,500 years old. And while the pyramids look their age, the oldest tree is still in its first flush of youth.

A quick arborist confession: quaking aspens can regenerate from suckers meaning the same tree can be in a constant state of living and dying. A sucker grows from the roots and that sucker becomes a tree. From that tree another sucker grows, and so on. The oldest tree is not a single stem but a sea of stems* There are so many stems that the tree is in fact a forest covering 106 acres. Each stem is genetically the same tree, the sea of stems, it is a clonal forest. So, while it is true to say that the quaking aspen in its first flush of youth, is also a teenager, middle-aged, falling apart, and a rotting stump all at the same time.

As living legacies go, quaking aspen have the endurance side sorted, but I’d not recommend them as a memorial tree. But even most of the usual contenders (oaks, redwoods, rata, pohutukawa, and of course the mighty totara) can outlive the structures built around them. At over 200 years old, some of the original oaks planted by the Duke of Wellington are still alive. But to ensure the continuance and keep the living memory alive, material has been propagated from those first plantings. Saplings have been produced and planted back onto the site. Newer versions of the same tree. The process can be repeated over and over again. The same tree (genetically speaking at least) can live on, for as long as we can take cuttings and plant them.

There are many living legacy trees and gardens around the world. In such places, there is a direct link to the past, present and future. A tangible link. You can actually place your hand on something that someone 200 years ago touched, and someone in 200 years will touch. That’s pretty special. So, if you find yourself working on a commemorative project, select your trees first. Plan wisely and future generations should get to enjoy your work, and of course, you will be ensuring that what is to be remembered will be remembered for the longest time.

• Written for New Zealand Landscaper Magazine

* Pando is the world’s oldest and largest tree, a quaking aspen (Populus tremuloides) located in Sevier County, Utah, United States.