Black Poplar

Black poplar trees: facts and stories

Poplar trees produce little balls of resin that look like amber. These droplets of golden resin sparkle on the buds at the end of the trees branches.

In Greek mythology, these droplets were thought to be the tears of the seven nymph daughters of the sun god Helios (the Heliades). The story goes that their brother, Phaethon, once borrowed Helios’s chariot (the sun) and lost control of it, risking burning everything in his path. Zeus intervened and struck him down with a thunderbolt, throwing him into the river Eridanos. Grieving continuously for their lost brother, the sisters were transformed into poplar trees. This is why poplar trees are said to ‘cry’ tears of amber.

These tears have special properties in nature: bees harvest this resin to make propolis (colloquially referred to as ‘bee glue’). In Greek, ‘propolis’ means ‘city wall’. Bees use this to strengthen their hives and their honeycomb structures. Humans harvest this propolis and use it as a supplement to strengthen their immune system.

Did you know?

Poplars are extraordinary at drawing up water. This tree must suck up hundreds of litres of water each day from the pond to supply all of its leaves. The tree manages to haul water 25m off the ground, which requires a colossal amount of strength!

Its roots are like small motors that absorb water, initiating the pumping action that draws water up the trunk towards all the branches. At the branches, an army of smaller solar-powered motors (the leaves) take over. Pulling on the water like a rope, the leaves lose water to evaporation in the sun, so they suck more water up the branch like a straw.

We would need a very big, fuel-hungry motor to achieve the same pulling force, but this tree manages to do it with little effort, in silence, and without polluting its environment.

The benefits of black poplar trees

The main benefit that poplars provide is their ability to draw up very large amounts of water from the ground and release it into the atmosphere. This adds humidity to the air, has a cooling effect, and makes the air more breathable during heatwaves. This humidity is good for human lungs in summer, as is the pure oxygen produced by the tree’s foliage.

The particularly ample foliage makes black poplar trees great for providing shade and creating little islands of cooler air on scorching summer days. Poplars are useful for reducing flooding, as they are able to dry out soil quite well. Lastly, these poplars also release a pleasant scent in spring.

How to recognise a black poplar

Leaves

triangle-shaped with a slightly rounded base and pointed tip; slightly serrated leaf edge and long leaf stem (petiole); fall from the tree in autumn (deciduous)

Foliage

dark green in spring with glossy top sides and light undersides; bright yellow in autumn; and no foliage in winter

Bark

grey to blackish, with deep furrows (grooves)

Specifics about this tree

This tree belongs to a species that is increasingly rare here. It is the largest black poplar in the region, and one of the champion specimens of its species in the whole of Belgium!

It has witnessed the evolution of the Flagey neighbourhood. Back in the 1930s, when this tree was still quite young, this tree oversaw the construction of the Flagey Building, which was designed in the ‘style paquebot’ (the ‘ocean liner style’ of art deco).

Slowly but surely, the tree’s growth caught up with the five-storey Maison de la Radio building. The tree developed a very ample crown, which is typical of black poplars. It stretches its branches high into the sky and spreads them out like huge satellite dishes. The conditions here are ideal for achieving this: the pond provides plenty of water for its roots to draw up, and there is plenty of light for its foliage to soak up.

The design and blueprint for this tree’s shape was already established and determined at the seed level. In its own way, the tree has become a living monument in this neighbourhood alongside the various surrounding buildings.

(Story and photos created by Priscille Cazin- Sylvolutions)

This portrait is:

- Enriched with an illustration from the Belgian Federal State Collection on permanent loan to the Meise Botanical Garden.

- An initiative of Christos Doulkeridis, Mayor of Ixelles , Audrey Lhoest, portfolio holder for Environment, Green Spaces and Planting, and Tourism and the Ixelles Communal executive