I often notice that certain conifers often have a whitish powder on what seems to be their youngest needles, giving them a blue green tint. Does anyone know what this is? Is it something excreted by the trees themselves, is it a yeast or some other endophytic microorganism? Very curious and unfortunately I don't have a microscope.
I believe this is actually crystallized sap which formed on and around the bud as the bud opened up and new leafs emerged.
Note that some coniferous trees have a powdery coating as part of the leaf itself, continuing on throughout the life of the leaf. Blue spruce is a good example of this, as its dark green needles appear blue/gray due to a waxy coating the needles. This wax can be easily scraped off the leaf.
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$\begingroup$ Thanks for your answer! In the case of blue spruce, does the powder diminish overtime, for example on shaded needles that receive less sunlight? $\endgroup$ – deasmhumnha Jul 19 '18 at 21:52
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$\begingroup$ Great question @DezmondGoff. I can confirm that conifers with powdery or waxy needles will have patches with significantly more or less coating, but I don't know what the causes of that are (whether it's time, sunlight, types of leaf). $\endgroup$ – cr0 Jul 20 '18 at 13:22