Amid growing urbanisation, deforestation and agricultural expansion, it's long been thought the number of trees across the planet is being reduced. However, that belief is probably wrong, according to new figures. The biggest ever analysis of global land change has discovered there are more trees across the earth today than there were 36 years ago. The study, published in the journal Nature this month, shows trees now cover 7 per cent more of the earth's surface - roughly 2.24 million square kilometres - than they did in 1982. This overall net gain is the result of a net loss in the tropics being outweighed by a net gain in the extratropics," the report states. The study, led by scientists from the University of Maryland, in the US, analysed 35 years' worth of satellite data to provide the most comprehensive picture ever made of the changing use of land. Tree loss in the tropics is caused by agricultural expansion, while the new growth areas [are] in regions which were previously too cold to support such flourishing life, suggesting global warming is causing previously unidentified changes to the planet's landscapes. The study ... states that 60 per cent of all change appears to be directly driven by human activity. Of the remaining 40 per cent, the study suggests, most of the change can be attributed to indirect results of human actions.