Why do small branches and twigs start to curl when they are on fire?

Question

Why do small branches and twigs start to curl when they are on fire?

In: 5

Answer 1

It’s a contraction as the fibers or pores collapse especially if they have water.

Think of grabbing a bundle of plastic straws, then when they are on fire they collapse and melt, reducing the overall volume they had.

I think it might be a similar reason of why leaves and plans can curl when they are lacking water or nutrients, oddly enough it can happen when they have too many nutrients too.