Pine tree pollination

Aleppo Pine (Pinus halepensis)

The Aleppo pine tree, the tree that has been planted along so many of our roads, in public gardens such as Buskett and afforestation areas such as L-Aħrax tal-Mellieħa and Miżieb, at this time of the year goes through an impressive change. 

The Aleppo pine is normally light green but just now the predominant colour is light brown although its hue varies under different conditions. If seen early on a sunny morning the tree is nearly yellow and shines as if it has a light of its own. When it rains it becomes much darker.

The changes are caused by the appearance on its branches of male and female cones. The cones are the reproductive organs of pine trees. 

The male cones produce pollen which is transferred to the female cones so that when it meets the female gametes fertilisation takes place. 

On pine trees, the transfer of pollen takes place without the intervention of any animal. Pines rely on wind to carry the pollen from male to female cones. 

This is a wasteful method as much of the pollen never reaches its target so the tree has to produce large quantities of very small, light pollen to ensure that at least some of it meets its female counterpart.

When the weather is right, that is, if it has not rained and the air is dry, the slightest breeze is enough to blow the pollen off the male cones. I

f there is no breeze swaying the branch slightly, as what happens when a bird lands on it, is enough to set the release of the pollen in motion. So much pollen can be released every time that this happens that the pollen looks like a small cloud of fine dust.

These changes take place very quickly and do not last long but few people notice them because many of us go through life without being fully aware of our surroundings. Our lives would be much richer if we had to take the time to look around more carefully and become aware of the obvious and the subtle.

This article was published in The Times on 23.03.2011