Z Fire

[Imp]

I actually am a fan of creeping barrages when I have enough tubes on hand to do them. Problem there, though, is that if you do close-range fights in really thick stuff (jungle, forest) you can usually expect to suppress or kill your own men about as badly as you do the enemy. Which is realistic; something like 10% of artillery shells fired in WWI ended up hitting friendly units, so you can't expect much better in the 1930's.

Which is one of the reasons why you use small calibre arty in woods jungles.

Small arty has a high ROF so still causes reasonable suppression when adjusted.
Causes higher suppression & fewer kills than the big stuff so you just pin your own men.
Doesn't leave craters in what is slow going terrain already.