The Lichen Study

A few weeks ago our class completed a study on two different types of lichens that grow on maple and ash trees.  These two types of lichens are Physcia millegrana and Candellara concolor.  Physica millegrana is a lichen that is more blue and green in color.  On the other hand, Candellara concolor is more of a yellow colored lichen.  What is a lichen, though?  Well, according to the site http://www.decodedscience.org/little-lichens-more-than-a-plant/20893 , a lichen is basically a hybrid between a fungus and an algae.  Different types of lichen grow in different types of air quality environments, good and bad.  We are studying the relationship between lichen growth and pollutants in the air, specifically SO2 and NO2.  What exactly are sulfur and nitrogen dioxides?  Well, they are each linked to one of the six criteria air pollutants, those being nitrogen oxides and sulfur oxides and neither are good for one's health.  So you may be wondering, where do these nitrogen and sulfur dioxides come from?  Well, according to the site http://www.epa.gov/airquality/sulfurdioxide/ , the major source of sulfur dioxides is a result of big industries burning fossil fuels as well as the burning of fuel that contains sulfur.  This is also where you find most of the sources of nitrogen dioxides.  These sources include motor vehicles and power plants.  This information was also found on the same site that is linked above.  So what kind of effect do these pollutants have on plants, say, lichens There are many different theories being said about this relationship, some saying that more pollution will lead to more lichen, others saying that more pollution will lead to less lichen in the area.  As a class it was being discussed that more pollution will lead to more lichen growth.  According to the site http://staff.concord.org/~btinker/gaiamatters/investigations/lichens/affectslichens.html , lichen will either be destroyed by the pollution or a different type of lichen more tolerant to the pollution will start to grow instead.  There are many different types of lichen, and some are more tolerant to pollution than others, so, a new species of lichen will grow depending on the type and the amount of pollution there is in an area.  So, how did we complete this study?  Well, our Professor gave us three areas to each find our own individual tree to measure lichen on.  It had to be either a maple or an ash tree, and you knew this because if you looked at the branches, they branch off in the same spot from the branch, they do not alternate which side of the branch a new branch comes off from.  They are mirror images on one side of the branch to the other.  Once we looked at the branches and found a tree, we had to measure the lichen around the tree in all four cardinal directions, using a wired instrument that consists of 4 vertically connecting quadrants which are each 100cm2.  We would hold this piece 1 meter above the ground to ensure it was a good area that air pollution might be affecting the tree.  Too low and your results might be inconclusive and too high the same.  That is why we measured around the middle area of the tree.  This is also where most lichen would usually grow.  So once you help the piece 1 meter above the ground, you had to look to see how much lichen there was present in each of the four quadrants, in all four cardinal directions.  This would tell you that if there was pollution present, which direction it was coming from more.  We would rate the amount of lichen present in each quadrant on a scale 0-3, 3 being a lot of lichen, 0 being no lichen.  My tree had no lichen present on it at all, so the standard deviation of my tree lichen was 0.  My tree was on East green, with GPS coordinates 39°19'33.22"N 82° 5'56.82"W .  The point of this study is to pass down the data collected for these trees from class to class so that lichen is being measured every semester.  Studying the lichen is very important to be aware of the air quality around the area, that is the purpose of this study.  Credit needs to be given to Beatrix Potter, a women from northwest England who was the first person in Britain who began to study lichens more closely and how they are like a fungus and an algae.  She painted them and noticed the similarities, so she began to study them once inspired by her paintings to begin her studies on how they are fungus and algae related.  Without her beginning the study of lichens, who knows if anyone would have ever started to study them and find out these things about them, like how they are related to air quality.  The pictures of my tree are posted on this blog.  I will have them labeled in it's respective cardinal direction.  You will notice that there is no lichen on my tree.  It was about ten paces away from the street, however, it was in the middle of a street.  Trees farther down the street in both directions had a lot of lichen on them, or more than my tree had, which was nothing.  Why do you think this is?  Well, as a class we were saying that it is due to more pollution that more lichen is present, say it makes sense that maybe when cars are stopped at the end of the street on both sides sitting idle at a stop sign that there is more pollution due to the idling of the cars?  That is very possible.  I hope this blog was helpful in describing how we completed the study, and also just how important lichen study is to air quality.

 

Here are the branches of my tree.  Notice how the branches branch out from the same points. 

 

North^

 

South^

 

East^

 

West^