I made some smaller test map pieces so I could try out various different ideas on them without being too worried about the wasted time and expense with the ones which didn’t work.
Rust print and burning only:
This works well, but I don’t feel it is enough on its own. The burn marks are also too precise and controlled. I may have to try this using gunpowder on a full size version.
Adding ink to represent the non-ash trees in the landscape:
The green ink I have is a bit too sickly. I might be better doing this in watercolour if I want to add colour in this way.
Adding black ink detail:
I like this combination of randomness and precision. My concern is whether this will translate well to the larger images. Maybe some small sections like this would work?
Here I tried using masking fluid to mask out a leaf pattern over the whole map, wetted the paper and drew around the masked area in black ink:
I don’t think this was very successful, the masked areas are too roughly done when on top of the (relatively) crisp rust marks. Also it ended up with two different images your eyes try to picture alternately, more likely to make you cross eyed than interested.
Adding an ink drawing of the cup-fungus (in white ink) on a midrib (in black ink):
This is similar to the previous test in fitting two different images on top of each other and again I don’t think this one works either.
Adding gold leaf in some of the burn holes:
Representing rays of hope in some ash trees hopefully surviving the disease. On its own it is not hugely successful, but it may work with the detailed ink drawings? It is too hard to tell on a small scale though and may have to be tried on a full size version.