It is once again that time of year, the time when trees that rely on wind pollination dump a really absurd amount of pollen into the air. The surfaces of outdoor objects become covered in a layer of yellow dust that is shockingly visible to the naked eye. When it rains, run-off nearly glows yellow as all this pollen is carried off.
I am always struck by just how costly this form of reproduction must be. To produce this volume of pollen, trees must expend a remarkable amount of energy and nutrients. And all because of the inefficient nature of this means of reproducing: when you must rely on the wind to bring sperm and egg together, you have to make a lot of sperm just to assure a little bit of successful seed production.
Ah, and such a waste wind pollination is when you consider its alternative:
Sure, on top of producing pollen you need to produce some sort of reward for pollinators, but think about how much less pollen must be produced by plants that engage in mutualistic relationships with animal pollinators! I am not aware of any study quantitatively comparing the costs involved, but I have to imagine that — in terms of raw resources expended — animal pollination has to be a lot less costly than wind pollination.
And of course there are costs to us. I am not a person who is allergic to very much, but my body definitely reacts to the level of pollen in the air of late April and early May. Given how much pollen is released during this time of year, I would be more concerned if my nasal passages and lungs did not produce abundant phlegm in an attempt to sweep away all this fine particulate matter!
Should we avoid planting trees that release so much pollen? Without better understanding which trees are involved, I cannot answer this question… but this time of year sure does make me appreciate the female variety of dieocious Ginkgo biloba trees. I will take their stinky fruits over pollen in my lungs any time of the year!