Piecing the jigsaw together

This week I'm working on my new environmental novel, and it's been challenging my creativity quite a lot.  I always knew when I started the book that I wanted the trees to be high intelligences.  I also wanted the big cats in that world to be telepaths.  So a major challenge was working out how both could talk.

Obviously, it wouldn't be with words out loud.  But having said that, I've written a creepy scene with my chararacter alone in the forest where she can hear booming sounds all around her.  I'd imagined that as low-frequency communication, half of which she can't hear.  That would make sense in a dense forest.  Low frequency sounds carry much further.  It's why the deep roar of a lion at the zoo at night reverberates all round the neighbourhood.

I now have to work out what produces those booming sounds.  I want it to be the trees, and I want to fashion some sort of gramophone horn to use to amplify the sound.  The challenge is finding something in the natural world that is the right shape for an amplifier.  I think that will have to be hollowed out dead tree trunks.  I still have to work out how to get the sounds through them, but that's half the challenge solved.

I think the sound will have to be produced by the trees' lower limbs, which my character has just discovered can move.  Yes, really.  And no, they didn't believe it at first either.  What I've devised is trees with two sorts of branches.  When they get above a certain size they grow rigid, using the usual cellulose and lignin structures. But when they are young and thin they can move about.

So how could I get the limbs to move?  I needed some kind of hydraulic mechanism. Trees naturally suck an enormous amount of water up their trunks.  They could evolve to divert some of that water through a system of organic hydraulic valves to move their limbs about.

I'm quite pleased with that solution.  But I still have to tackle conversation with the cats.  That will involve the mycelium, which transmits hefty amounts of electrical current.   If I give them some sort of nodes which act as transmitters, that could work.

I haven't even started on working out how the mysterious lifeform deep underground is commmunicating.  I've got lots of creating still to do, but it's been great fun.