I was out for a walk today and came across a willow that seems to be giving up its medicine to the local possum population.

You can see the teeth marks, and that they’ve stripped the bark to quite a height.

They’ve almost ringbarked the tree.

Those were fresh eatings.


This is an older one. There were a few of these on different trees. You can see the problem – the willow is getting ill inside and a deeper and deeper fissure is opening up. An interesting result from the meeting of two species considered pests in NZ.

You can also see the dark bark layer between the outer grey and the inner white. That dark layer is what you would be after if you were harvesting the inner bark.

Note also the short horizontal lines in the white inner part and how they are similar to the small marks on the outer bark. These are lenticels, structures in trees and other plants that allow gases to move in and out of the tree. Lenticels are more obvious on trees like birch or stone fruit eg cherry trees.

Willow is a strong enough medicine. It contains salicylates, chemicals that relieve pain when taken internally or externally. Aspirin is based on this. I’d love to know if this is specific medicine for the possums or if it’s food.