I was reading a blog post from military historian Bret C. Devereaux, where he is talking about trench warfare, and i was curious about this part:
"The point here is that casualty ratios didn’t reliably favor the defender in World War I. They did reliably favor the Germans who were often, but not always, the defenders in the west (in part because the Germans held the best ground over the entire western front almost without exception), though not by enough to off-set the German inferiority in manpower and materiel compared to the entire coalition arrayed against them."
And I was wondering if anyone could describe some of these reasons for lower German casualties?
The quote you used does accurately describe some instances in the first World War where even though the Germans were defending, they still had similar casualties to the Entente powers. There is also examples where casualties were less than the entente powers. My answer will stick mostly to the western front as German organization and planning over the slow and disjointed Russians in the East is what created their casualty difference there. The eastern front was far more mobile due to the size of the region so trench systems were far less common especially compared to the gridlocked western front that is synonymous with our view of trench warfare.
One thing that helped the Germans avoid more casualties in the war was the way they built trenches. The Entente power's trenches were most built straight out of digging into the earth and using wood, wire mesh, or sandbags to reinforce the walls. Most of these trenches were only about 6 to 8 feet deep with dugout in support trenchs dug to only around 16ft, with some trench lines even shallower then that.
The Germans had observed the process of the Russo-Japanese war from 1904-05 and had seen the use of trench warfare there. During WWI, they based a lot of their knowledge off of these studies and used reinforced concrete in the construction of their trenches, something the Entente rarely did. They also made extensive use of dugout bunkers, usually a minimum of 16ft and would even reach multiple stories in some places. They would also provide ventilation for them to avoid the hazard of gas attacks. They could sit and ride out many of the initial bombardments that precluded many offensives and go to the surface whenever the advance started. Some of the bunkers could be collapsed by the artillery bombardments, but most were very suitable to surviving them.
The Germans also generally had greater amounts of heavy artillery, especially in the first couple years of the war. Entente planning would fail to properly neutralize the German artillery before many offensives and it would mean the German artillery could pound the Entente soldiers as they cross no man land. German doctrine also made better use of machine guns, even dictating interlocking fields of fire that would create large kill zones for infantry trying advance.
As the Entente was more focused on the offensive and the Germans viewed that they really only needed to hold onto the land they already have as they were well inside France, this explains why the Entente didn't do the same and use concrete in trench construction. Their view was why waste the resources on better trenches as it would discourage the attitude of the advance. Certain technologies like the tank could assist in advancing, but like most wars that came before, it was expected for the attacker to face more casualties to overcome the defender. Not always the cass but still happened throughout the war.