Trees in trouble nowadays

Trees in trouble A Big trees are incredibly imporant colically For a start they sustain countless other species. They provide spelter for many animats and their vakt and branches can become gardens hung with green terms, orcinds and bromelias, tosted with masses and draped with vinas With their tali canepius basking in the sun they capture vast amounts of energy This allows them to produce massive crops of fruit flowers and foliage that sustitin much of the animal de in the forest B Only a small number of tren species have the genetic capacity to grow really big The mightiest are native to North America, but big trees grow all over the globe from the tropics to the boreal forests of the high latitudes To achieve giant stature a tree needs three things the right place to establish its seedling good growing conditions and lots of time with low adult mortality Disrupt any of these and you can lose your biggest trees C In some parts of the world, populations of big trees are dwindling because their seedings cannot survive or grow. In southern India, for instance, an aggressive non native shrub, Lantana camara, is invading the floor of many forests Lantana grows so thickly that young trees often fail to fake root With no young trees to replace them, it is only a matter of time before most of the big trees disappear Across much of northern Australia gamba grass from Africa is overrunning native savannah woodlands The grass grows up to four metres tall and burns fiercely, creating super-hot fires that cause catastrophic tree mortality. D Without the right growing conditions trees cannot get big, and there is some evidence to suggest tree growth could slow in a warmer world, particularly in environments that are already warm Having worked for decades at La Selva Biological Station in Puerto Viejo de Sarapiqui, Costa Rica, David and Deborah Clark and colleagues have shown that tree growth there declines markedly in warmer years "During the day, their photosynthesis", shuts down when it gets too warm, and at night they consume more energy because their metabolic rate increases, much as a reptile's