Mulberries

If a disease killed a mulberry tree, it would lead to the loss of its ecological contributions, such as providing habitat and food for various species, including birds and insects. Additionally, the tree's death could disrupt soil health and local ecosystems. For farmers or industries reliant on mulberry for silk production or fruit, it would result in economic losses and potentially affect local agriculture. The surrounding environment might eventually recover, but the specific impacts would depend on the extent of the disease and the resilience of the ecosystem.

It was to do with the Allied landings in France , 1944. For more info check this page out: http://search.eb.com/normandy/articles/Mulberry.html

The construction of the mulberry harbours directly after the invasion.

Briefly, artificial harbours were built and floated across the English Channel to the French coast in order to speed up the unloading of fleets of large cargo ships from America with shiploads of men and war materiel to support the Allied advances across the Western Front. These floating harbours would be used until suitable natural harbours and infrastructures could be captured and used.

The German occupiers had booby-trapped the docks, wharves etc. in the few French harbours to prevent their use during any successful invasion of the French coast.

Without the success of Operation Mulberry, the war in Nazi-occupied Europe would have dragged on for a very long time indeed.