I’ve been wanting to do something with iNat data for a while now and finally had time to do a side project over winter break.
One of the unexpected consequences of attending college in Connecticut has been experiencing autumn twice a year. I watch the trees of New Haven change color during late October and early November, then return home in Georgia for fall break and watch the leaves change color again.
I understood the basic principle behind my double-dipping of fall. But what would it look like actually to observe leaf color change across the whole continent? I decided to tackle this question.
I had three qualifications choosing a tree species. It had to have a drastic fall color change, a large range, and many observations. After considering Sugar Maple, (Acer saccharum), Sassafras (Sassafras albidum), Trembling Aspen (Populus tremuloides), among other trees, I finally decided on Red Maple (Acer rubrum), which had the highest observation count.
Figure 1: 2019 research grade observations of A. rubrum with leaves. The color of each marker corresponds to the dominant color of the leaves in the respective observation. Each marker disappears 10 days (frames) after it first appears. At the end of April, observations get green as trees “green up,” and fall colors start appearing at the start of October and spread south.