Light has a huge effect!
Since July 2013, I've been conducting experimental demography at the Las Cruces Biological Station, in Costa Rica. With the help of my field assistant, we pulled more than 1000 seedlings from the forest and put them into pots. Half of these pots were put into a "high light" treatment, and other half went into the "low light" treatment. I returned in October to check on things, and boy, the plants looked great. I returned about a week ago, and was shocked to see that some of the plants had grown more than a foot in just a few months. I am amazed at what these little guys can do.
