Trees can talk

Kruger National Park | February 2019

We often only credit mammals with complex communication, yet reptiles, fish and even trees are capable of communicating over a fair distance.

The process of “Jasmonation” or “Methyl Jasmonate” is a tactic used by certain tree species to warn one another against a detected threat. This form of biocommunication is used by a variety of Verchellia and Senegalia species (previously known as acacias). They naturally emit a fragrance, and when they detect that they are being heavily browsed upon, they release a distress hormone of ethylene into their fragrance to warn other trees downwind of the potential threat. The trees downwind will then up their tannin levels making the vegetation much less palatable and difficult to digest.

Certain animals through evolutionary history have learned to interpret the trees’ ethylene signals to one another. In particular, the giraffe knows that all the trees downwind are going to have received the distress signal and will have tannin-laden leaves. To counteract this, the giraffe will walk and feed upwind, spending a few minutes at each tree before moving on to another that is unaware of the giraffe’s presence.

This relationship shows us the complexity of trees, their ability to communicate, as well as the ability of mammals to adapt and overcome challenges in their environment. This is fantastic to look out for whilst on safari, and lends a new appreciation for giraffes and the fantastic trees that surround them. Who would have thought that trees could talk!

Image by Sean Bissett, ‘A lesser spotted eagle at moonlight.’