Calculating the average tree cover in an area allows us to estimate the extent of the world’s forests. Forest landscapes can be mapped in various ways and is often done in conventional maps. However, much of the land area is not covered by forest and the few remaining untouched forest landscapes keep shrinking while deforestation continues.
This visualisation of the global tree cover shows the quantitative distribution of the world’s forests. In a ‘gridded cartogram’, each of the grid cells shown covers an equal physical space and is then resized according to the total amount of space covered by trees in this area. Additional topographic features showing the elevation similar to normal topographic maps (from green for the lowest lying areas to brown and white for the highest regions), and the surrounding bathymetry of the world’s oceans remain as guiding elements in this cartogram.
While conventional maps are ‘equal area’, ‘equal distance’ or other projections, this map gives us a new visual understanding of the distribution of the world’s forests while preserving the geographical accuracy by retaining the topology between each of the grid cells.
The visualisation is an image of the fragile forest-landscapes which make up approximately 31 per cent of our land area. They are the world’s lungs, providing home for a multitude of the most complex and diverse ecosystems on the planet. However, they are also the basis for the livelihoods of many people, and an important economic factor, and are therefore under threat of deforestation – especially in the tropics – which make up a lot of the spaces in this map.
Benjamin Hennig is a senior research fellow in the School of Geography and the Environment at the University of Oxford. He is involved in the Worldmapper project and maintains the visualisation blog www.viewsoftheworld.net.
This story was published in the January 2015 edition of Geographical Magazine