All discussion on how to beat the Lizardmen is to be posted in this thread. The best tactics will be amalgamated into this post.
Lizardmen are a toughy. My best friend plays the cold-bloods and he loves his big characters, so its all about the toad (Slaan mage priest) and two decked out saurus old-bloods (I think thats the name of their fighter heroes). Against his army I always take my Treeman, ALWAYS. Whether its taking on units of Coldone cavalry or blocks if saurus, the big tree gets the job done.
For the most part, I try to to pick off the blocks of saurus and annoying skinks first, then going for the temple guard with everything thats left. This way I can spend most of the game in combat ( his Slaan mage usually uses lots of missle magic, which cant be used on engaged units) and right at the end of the game I usaully break his temple guard with a combo of dryads, Treeman, wildriders, and every character I have left.
Oh, and don't expect your archers to do as well as they usually do. Saurus are tough as nails and skinks skirmish.
Are Lizardmen really enemies of the Asrai? I mean, both don't want their forests destroyed, they both hate Beastmen and Dark Elves, and they both are friendly with the High Elves... but since this is about beating lizardmen, I will betray my first army.
The best way to beat Lizardmen that have:
magic: If you are facing a Slann, then you want to REALLY boost up on magic as they have plus one to cast and dispell. Also, if you are facing 4th generation, then they can't miscast so that makes it harder to kill. Basically, go for the Temple Gaurd he should be with, or if he is alone, get some waywatchers to go over there and shoot the heck out of him.
Power (oldblood): If you are facing an Oldblood, then watch out for the potential Carnosaur. D3 wounds against large targets will kill your Treemen. Blood Frenzy will kill most anything too. Basically, try to shoot off the Oldblood and whtever unit he is in, but if it's Cold-One Riders, then you want to double-triple charge that unit with whatever you have. Hopefully it will cause Fear/Terror, otherwise you are in for a tough ride. To beat a power army, you will also need magic, because with only 3-4 dispell dice max, the Lizardmen will find it tough to dispell. Also make all your terrain that you place (if possible) forest because then they will have a hard time moving around since they will most likely be big saurus blocks. M4 and lots of trees around won't help the lizards.
skinks: The bigger the unit of elves, the better. With 6's auto wounding, skirmishing, and aquatic for only 6 points each, watch out. Take big blocks of warriors or cavalry or anything with a reasonable save that can have better than unit strength 15. You need to charge then with Fear/Terror causers too because LD5 will make them run 3/4 of the time. If they stay in combat though, then bigger numbers will help outnumber them and make them run, because LD5 getting lowered is even worse for them.
These are the three types of armies I can think of that Lizardmen will do. Since I am a Lizardmen player this should be pretty accurate.
If there are any questions about defeating Lizardmen (who I completely agree would be friendly with the Wood Elves....) please contact me.
Wanderer's correct, though I'll simply warn you all of a few things...
1. 2nd generation Slann are monsters, if used right they gain an extra power di per spell they cast. Plus they're at 8 wounds and will have 6 spells usually, one of which being Drain Magic which makes your wizards lose certain types of dice when they roll. (the highest level canceling out 4's, 5's, and 6's) Plus his constant 4+ Ward save is a pain. If you're fighting a player who knows his stuff with a Slann, he'll tend to hide it behind terrain to protect it from enemy sight and make a Skink Priest (lvl 2 wizard) have a flying magic item, and anything the Skink can see, the Slann can see. Usualy Lizards will probably take Fire against Wood Elves, and Orion help you if he rolls Conflageration of Doom, cause he'll get that free power di for the spell, probably 2-3 of his own dice (plus he might have an item so he generates more dice) and Conflag needs only SIGHT to hit you.
2. The JSoD. Which stands of the Jaguar Saurus of Death. What you're looking at is a single character usually with a 1+ armor save an a 4+ Ward against anything above str 4. He'll have movement of 9 (so a charge of 18") and 4 str 7 attacks, along with being immune to phycology if built correctly.
My suggestion, take out the skinks with dyrads if you can, ASAP. Beware of Terradons, Kroxigors, and other fast moving units that hit hard. Treemen can deal damage, but if you foe has a decent trick up his sleeve or a High-Level Slann, burning a Treeman to a crisp is a walk in the park.
As for killing a Slann, the best way is to outnumber him in combat with fear-causers and pray for the best. In 7 years of gameplay, I've never seen a Slann killed by anything other than outnumbered by a Fear causer. In fact, when fighting him, try to snipe the Skink Priest and trap the Slann, not allowing him to cast at all.
If you can kill the Slann....you win. As for other units such as Saurus, Eternal Guard can probably teach them a lesson, though never forget Treekin.
In conclusion, you usually want magic resistance (scroll caddies) and alot of dyrads, glade guard, and sneaky attacks. Big monsters can survive as long as the Slann cannot see them. NEVER underestimate a Slann. That's all for now.