Can't Stand The Heat? Hug A Tree



Trees are a common hangout for many animals and insects. Under them, on top of them, next to them, around them, trees may be habitats or just places to go for temporary respite.  For some creatures trees are a source of food or a sharpening tool for their beaks, claws, or teeth. Some trees provide shade and shelter. Others provide a hiding place for certain animals.  Researchers at James Cook University in Australia recently learned of another function of trees, which they reported in the June issue of Biology Letters.


Koala bear, born to hug a tree!: image via google plusKoala bear, born to hug a tree!: image via google plus

The bark of certain trees is cooler than barks of other trees and that difference, say of even 5 to 10 degrees, can mean life or death to some animals.  If cooler trees are not near the habitats of arboreal creatures, they can die in a heat wave.

That's exactly what happened in 2009 in New South Wales, Australia, when one-quarter of the population died during a heat wave that year.

The James Cook researchers followed 30 koala bears on French Island, Victoria, and posted portable weather stations on poles in the area to record 'images' of the air, tree, and animal heat.  Interestingly, the koalas moved their residences from their normal habitats to cooler trees in hot weather, even though though the trees were not a food source for them, lowering their body temperatures and reducing their need for water by about 50 percent.

The koala watchers noted that in microclimates where cooler trees are not available, koalas will lick their fur and pant, but this can lead to dehydration and death if sufficient water is not available to rehabilitate them. This is clearly what happened when a large population of koalas perished in New South Wales.

So, trees also can perform the role of thermoregulation, a factor that the researchers say should be considered in assessing the habitat suitability for animals in the present and future climate conditions.  Dr. Michael Kearney, one of the study's researchers, proposed that it's not just koalas than benefit from the cooler tree trunks but other "tree dwelling species including primates, leopards, birds, and invertebrates" would benefit from them as well.

sources: Biology Letters via Eurekalert

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