Fall Foliage Post #2

In the few weeks that have gone by since my last post, some leaves have shown dramatic changes in color while others are hesitant to change. 

The sycamore, which used to have a somewhat dense coverage of bright green leaves, has lost some of that density and more sky can be seen through the branches. In addition, the leaves have taken on a brown hue, making their leaves a bit less vibrant. The leaves also seem to be drying out and shriveling up as if they are giving up slowly before completely dropping off of the tree. This makes me believe that the tree might be reabsorbing some of the water and nutrients in the leaves before letting them fall.  
The locust trees on the left side of the image seem to have undergone a process similar to that of the sycamore. All of the trees in this area of woods look more brown and less dense, but have not yet changed to vibrant colors as seen in other types of trees. Because the trees that are growing close to other trees are not changing as drastically as those growing further apart (like the sugar maple), I have proposed that species of trees that grow in higher population densities do not rely on vibrant color change to prepare for winter. 
In stark contrast to the other types of trees, the sugar maple to the left of the train station has transitioned to a bright orange color. Although it looks a bit brown in this photograph, it has been very vibrant in the past few weeks, catching the eyes of everyone who has passed by. The sugar maple has more of a round shape than the locust trees, showing that it prefers to grow further from other trees, which might have something to do with the differences in their autumn actions. 
In nature, the leaves that are dropped from the tree would normally stay near the base of the tree to decompose. I believe that the changes in color could result from this phenomena. For instance, the sugar maple's orange leaves might attract organisms that would speed up the process of decomposition and return the nutrients to the soil near the base of the tree. The trees that do not have bright leaves might not need to attract as many decomposers because the trees are living in the woods, where small organisms are plentiful all of the time. 
Similarly, the trees might rely on this ground covering of leaves to keep the soil a bit warmer and the different colors absorb different wavelengths of light, which would affect how much heat is absorbed into the ground. 
However, because humans often rake up leaves that fall into our yards and campuses, we may be altering how the trees can use either of these proposed methods to thrive in the winter.To study this further, I would have to find these species of trees in the wild and study these processes.