Sorry Lis I completely got side tracked and forgot about this thread!
Some important things to focus on:
- Try not to rush
- Discomfort(what's making him nervous)
- Defense(make it clear you are on his team)
- Territory
- Recognizing the signs(body language)
- Training with Praise
- Encouraging play
- Cats have very good memories
My suggestion would be to spend some more play time outside not just in your garden but also in other areas where you go walkies. Get down to his level and praise and maybe take some treats he likes with you in your pocket. But don't let him beg for the treats only give them to him when he's listening to you. Using a clicker training method might be an idea and may give you a bit more structure. It's very common as with dogs too for animals to feel threatened on the lead, cats are so very territorial as well. You need to take all of these into account for your situation and be sure you recognise the behaviour as it can happen anywhere, not just in the woods if this is something he's uncomfortable with. There are a number of things you can do to help him feel like it's more 'his' territory.
for starters, sprinkling a bit of his used litter in the area of the woods you like to go, be sure it's along the path as well. Basically when he comes into the woods he is entering someone's territory so he senses this and is ready to attack, you either pulling on the lead or coming up behind him too quickly causing him to react in a way of defense. My Ocicat has similar behaviour but is a quieter nature and more trustful with me so she just growls when we enter the woods. I then distract her with my voice saying: "Come on Trouble good girl" and I make a chirping noise and get her moving, and sometimes with have a good run with her through the area of discomfort, now with time she just rubs or flicks her tail up and shimmies it when she gets to an area she's unsure of, this is my cue to tell her 'good girl' and chirp her on. She will still growl on occasion but I interrupt her and move her on.
Distraction may be a good element for you here, maybe with the treat or chirping, clicking or a da bird toy?
Once you enter the woods a little way, not too far, have a seat and him come to you and settle with you. Don't move just sit let him mark you and smell you and have an explore, praise, play and then click/chirp and move on to the next spot. As soon as you see him showing his signs have a seat again, quietly let him come to you on his own terms and again praise, play and click/chirp good boy... turn and go home the first time. Then repeat again some other time, don't do this every day. Do it occasionally at first, leave the woods as a treat.
See how you get on with this and try these exercises out of the woods as well with lots of praise! I would also encourage you to get some Feliway diffusers for your house and some FeliFriend Spray for your trouser legs when you go out walkies. Give them a spray before you leave.
Let me know how you get on.