In most of the paintings and photos I have seen, WW1 battlefields were dark, muddy wastelands with sparse and destroyed trees, while most of the WW2 pics are not like this with their trees and environment being mostly intact. Why was the first world war more destructive to their surroundings?
Firstly, it was not universally true that the whole of the western front was a morass of mud filled craters, shattered trees, and endless poetry.
In quieter sectors where there was a degree of ‘live and let live’ there would be grass, wildflowers and birdsong. Indeed, when Rawlinson attacked on the Somme in July 2016, his men advanced through waist-high grass and untended crops.
The stereotypical image of a WWI battlefield did hold true in more active sectors, or where there had been a major offensive – Verdun, Arras, for example. The Ypres Salient probably best represents the common stereotype of a WWI battlefield – hotly contested from the autumn of 1914 through to summer of 1918 – Ypres had a high water table meaning mud could become a serious issue, while the lack of movement meant the same ground was subjected to extensive and intensive bombardments for many months, and sometimes years. To add some feeling to how extensive these bombardments could be, the British bombardment prior to opening the battle of the Somme utilised around 1.7 million shells, and this was far from sufficient to demolish the German defences. At the opening of the German Spring offensive in 1918, the Germans fired 3.5 million shells in a matter of hours. Germany alone was producing 12 million shells a month in 1916.
On the other hand, WWII typically saw a greater degree of mobility afforded (chiefly) by increased mechanisation and radio communication. The effect of mobility was to spread the damage over wider areas, rather than concentrating it in a relatively small square mileage. Nevertheless, where mobile warfare was not possible, conditions similar to WWI again became apparent, this being particularly true of large scale urban battles typified by Stalingrad, where the environment of destroyed very thoroughly indeed.
TL;DR – it wasn’t always the case, but in WWI the destruction was concentrated in smaller areas by lack of battlefield mobility.
Sources
Norman Stone – The Eastern Front John Terraine – White Heat Martin Middlebrook – The First Day of the Somme Anthony Beevor - Stalingrad