Why am I bothering you with this particular table? Because it straddles WW I and shows the effect of the war on the hop trade. Or lack of effect, in some cases.
The four countries with the biggest share of hop production - Germany, USA, UK and Czechoslovakia - remained at the top of the pile for most of the 20th century. With the exception of Britain, whose hop industry collapsed in the 1980's.
It's a great irony that the country to profit most from the effects of the war, the USA, wasn't brewing any beer at all by the time of the last figures. Presumably it was exports that kept hop growing alive in the US. I can't think of many uses for hops other than in making beer.
|Share of world hop production by country|
|Czechoslovakia formerly Bohemia||10.01%||11.85%||14.43%||14.41%||11.67%||11.63%|
|Barth Hop Report 1914-1915 to 1920-1921|
In Britain and Belgium (more surprisingly) Belgium the war appears from this table to have had little effect. But if you look at the acreage under hops and the quantity of hops produced, you can see that this wasn't the case.
|Hop production and acreage|
|Barth Hop Report 1913-1914|
|Barth Hop Report 1922-1923|
(I've used different years for the production because 1913 and 1921 were both years with a particularly bad harvest.)
In absolute terms, production fell everywhere except France. And the only reason it increased there was because of the transfer of Alsace-Lorraine back to France. Globally hop production was approximately cut in half as a result of WW I.