Paul Laverty got the idea for the movie after reading a newspaper article about the selling of Spanish ancient trees to Europe or Asia for decorative reasons. He mulled over it for a decade before actually writing it.
The trivia items below may give away important plot points.
Alma mentions that the distance between Dusseldorf and the town where they live are about 1,650 kilometers (1,030 miles). It locates the Spanish town around the center of Valencian Community (east to Spain).
The company that acquired the olive three is identified as RRR Energy International. This company is fictional. Although the RRR's web page shown in the movie was real, it was closed after the filming concluded.
Each day Alma's grandfather leaves a little stone in the place where olive tree was planted. Since then the olive was uprooted about 12 years ago, it would imply that the amount of little stones seen in the movie would ranges between 4,400 and 4,800 stones.