Both are brilliantly made by Widerstreit, first one he meant as a rework for normal trenches, second one you could make trench lines ala WW1 which we thought would be best used for the Eastern Front Armies since they had a fair amount of trenches there, especially around the Kurks area. They could double up as anti-tank ditches since they allow the movement of vehicles over them but slow them down significantly.
Also another note, these trenches provide the same Green cover as other objects but the trenches themselves provide a damage reduction debuff of sorts, I forgot what exactly he told me he put them, so think of it as Green cover on steroids where it's around 30 or so % better than regular Green cover.