Eucalyptus tree leaves turning brown and dropping?

Hi, I'm new to the world of gardening moving into my first home with a garden in march. I have a tall established eucalyptus tree in the back garden. I've noticed the leaves are turning an orangey-brown colour and starting to drop. Does this mean the tree has a disease or is it because of the heat? Or something else? Thanks Mel ☺️

 

I think it just might be natural leaf loss.
All evergreens drop leaves, but tend to do it at different times to deciduous trees, they stay evergreen but still have a leaf change.

The bark dropping of Gum trees is also something that happens.

 

Thanks for the replies. Leaf dropping seems to have calmed down since I posted. So fingers crossed it will be okay!