Today we had our first look at the Luquillo Forest Dynamics Plot – a 320 meter x 500 meter section of forest in which an incredible thing has been accomplished: the identity, size, and position of every tree (with at least a 1 cm diameter) has been recorded. This is no small feat in an area with steep hills, muddy slopes, and frequent disturbance from hurricanes. Long-term researchers have made this plant census for multiple years, so the dynamics of the forest – growth, births, deaths – can be understood. You can see in the above picture that the entire forest is gridded – here, shown at 20 meter intervals, but marker posts are actually found every five meters. The forest becomes addressable, much like a home in a large city. Below, you can see one of these markers.
Each tree is also uniquely tagged, so its growth can be tracked over multiple years. Hundreds of thousands of stems have been tagged in this study – below, you can see a tag on one of the younger palms. This is actually the 131,301st stem recorded in the plot!
We will be making our own surveys of a subsection of this plot, and measuring leaf traits (like thickness and area) for the species we find. The goal is to be able to compare the forest at this site in Puerto Rico to other forests in different parts of the world, for which the exact same measurements will be made. It is a challenge to find appropriate sites that don’t interfere with the research of other groups, and that don’t unduly disturb the fragile soils. Fortunately we had a friend watching over us this afternoon – an endemic Puerto Rican lizard cuckoo!