approximately 37 million km² - or around ¼ of the world's land mass - is covered by natural forest, a habitat which is home to the majority of the planet's wildlife, so it's no surprise that scientists are eager to study as much of the planet's forest canopy as possible before the population does away with trees altogether. however the problem they face in their quest to sit at the top of these masses of greenery is that access to the uppermost layer isn't always easy to come by, whether it be due to safety concerns on the part of researchers, their inability to physically reach the heights necessary, or the dangers presented to the canopy itself when interrupted by humans.