Weather and Health: Allergies

Spring weather arrived early this year in many parts of the United States. Our warm winter followed by record high March temperatures triggered an early bloom for the many plants and trees that release pollen.  As a result, allergy season was off and running ahead of schedule.

Pollen is a fine powdery substance that is part of a flowering plant’s reproductive process. It is also a type of histamine that causes seasonal allergic rhinitis, also known as hay-fever. The American College of Allergy, Asthma and Immunology reports that roughly thirty-five million people suffer from seasonal allergies across this country.

Allergy victims even have a difficult time in the urban environment of New York City, as street trees line almost every block.  The city’s ubiquitous Norway Maples and London Planes are both major pollen producers. According the National Allergy Bureau, yesterday’s concentration of tree pollen in NYC was ranked as “high”.

The early start to allergy season this year does not necessarily mean an early end. Doctors say that even after tree pollen production slows down, grass and ragweed pollens can cause reactions for allergy sufferers until the first frost of next winter.

Flag Trees

Objects that indicate the direction of the wind are known as weather vanes.  Not all, however, are man made.

Flag trees, for example, are living weather vanes.  They show the direction of the prevailing wind in a particular location.  On mountain ridges, where trees are constantly exposed to strong winds, the windward facing branches of a tree are often stunted or killed. On the leeward side, the trunk shelters the branches.  This allows them to grow to normal size.  As a result, the tree is sculpted to the shape of the wind and resembles a flag waving in a breeze.

These deformed trees are common features in the windswept sub-alpine landscape, but are not limited to that terrain.  Flag trees can also be seen in the tropics, where the strong, sustained trade winds contort trees in a similar fashion near the equator.

Flag Trees

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