Wow, I would definitely expect higher numbers in England and the UK. Maybe some of the plants that cover significant parts of your country are just not classified as trees/forest. I am really glad that more than a third of my country is covered by trees though - once you leave the city and keep walking/biking/driving in any direction for some time, your chances are you will hit a forest soon or later :) It must be amazing to live in Finland (72%) or Sweden (69%) though.