[M.A. Lugo]

M.A. Lugo  asked the Naked Scientists:
   
Hello Naked Scientists,

I was listening to several podcasts the other day and I came across an explanation you guys gave to a Cambridge student about how do trees cope with winter.

Now I think that the answer you gave the student is not entirely correct because I am originally from the Dominican Republic and we get a fairly stable amount of daylight throughout the entire year and our trees go crazy in autumn almost like those in the UK.  Now, the trees don't get completely "naked", but they lose a big percentage of their leaves.

What do you think?

[Don_1]

Deciduous tropical trees loose leaf for different reasons from those in the more temperate regions.

As you have observed, not all leaves will be shed, this is because the tree does not go into a dormant stage as would happen in the British winter. The deciduous tropical trees loose leaf to conserve water.

Heat from sunlight causes trees to loose water through their leaves, shedding leaves is the trees' means of reducing water loss during times of drought and has the added advantage of opening up the forest canopy to allow rain to reach the ground easily, when it finally comes.

Since rainfall in the Dominican Republic is at its lowest from December to March, but temperatures will remain at around 82^o F, it would be expected that this would be the most likely time of year for trees to need to shed leaf.