With  all the wildlife, it's easy to overlook the millions of trees in the Kruger National Park. Now two scientists have shown that what happens inside the park's deciduous trees is often astonishing - if less visible.Edmund February, from the University of Cape Town, and Steven Higgins, a professor of botany at the University of Otago in New Zealand, set out to see how trees, such as marula, red bushwillow and silver cluster leaf grow a full canopy of leaves within two weeks of spring.They were intrigued by the trees' ability to do this, even though the Kruger soil is low in nitrogen, vital for plant growth.The scientists monitored the same trees for a year, taking samples of leaves and twigs and analysing their make-up.Their results, published in the academic journal PLOS ONE, show that when leaves are ready to fall, the nitrogen in them is transferred back into twigs, ready to be used in growing new leaves."Such a strategy divorces a plant from a reliance on a continuous nutrient supply," say the scientists...