If you want dry tinder in a wet environment you need to put some extra effort in. Don't expect to find it lying around becasue everything exposed to the atmosphere is wet. But you can still get tinder (not including the dating app, you have to download that...).
So where's is there a good source of dry material; the inside of logs is dry right?! So if you can split a log. You should be able to do this with a good sized knife and some basic tools (large log as a hammer, etc). The inside of the log is nice and dry (the wood needs to be old wood without too much sap). You can then use your knife to shave the inside of the log. Providing you shavings are nice and thin you should end up with a nice trydry tinder material.
Bark off a birch tree is good too, providing it's not been too exposed to the elements, here's a ray mears video showing how to do this using brich bark. The techniques are similar for making tinder from a log. Basically you just need to increase the surface area of the dry material.
Basically anything wooden that's dry and isn't directly exposed ot the elements can (with effort) be turned into tinder.