Ranger Steve’s Nature Niche: Rain Catching Leaves

Recently it was brought to my attention how events in nature frequently slip past me without notice. In the book A Year in the Maine Woods” Bernd Heinrich noted water droplets bead on the undersurface of fallen leaves during a rain if they land bottom side up. I have noticed water beads on leaves but had not noticed them being restricted to the lower surface.

After the next rain, I investigated while walking the back 40. The upper surfaces were evenly wet while clusters of silvery bead beauties radiated light from the bottom surfaces. I should have noticed this sometime during the past six decades. If I had, it did not register in the recesses of my memory.

A friend that teaches botany at a local university told me he had not noticed it either. It is amazing how everyday events escape our attention.

I had not mentioned it to Karen but a couple weeks later she made the discovery herself. She decided to capture the richness of water drops on fallen leaves. Thousands of leaves covered the ground and a recent rain insured there would be drops on leaves. She headed out with high hopes and camera in hand.

She found leaves with water beads on the duller bottom surfaces and continued the search for beads on bright red upper surfaces. She found leaf upper surfaces she wanted to photograph but they lacked water beads. The water evenly covered those surfaces enhancing a red gleam. Her search failed to find leaves having bright upper surfaces with tiny silver domes. Only duller lower surfaces held droplets.

She shared her discovery with me and I told her that I had recently made the discovery after being alerted to it by reading about it first. It was wonderful she made the discovery independently through careful observation while exploring outdoors. I wish I were as observant as her.

After sharing with many people, I have been asked why one surface holds beads and the other does not. I am not completely sure but I have a good hypothesis that needs testing. The upper surface of leaves has a thick waxy cuticle that helps prevent water loss when exposed to sun and wind. The lower surface is more protected from direct drying by sun. Wind moving air across the pitted lower surface of leaves has better protection.

We are familiar with how moving air causes “wind chill” by sweeping heat away from our skin to make the temperature feel cooler. It hastens water evaporation from our skin causing rapid heat loss.

The bottom surface of leaves is covered with tiny pores called stomatas where oxygen and carbon dioxide are exchanged. The pores create a rough surface compared with the smooth waxy upper surface. I suspect the rough surface holds water droplets while the smooth upper leaf allows the water to flow easily.

For those of us observing nature niches in our backyards, it is amazing how much we walk past without notice. Exercise your observations skills and have fun challenging friends and family to make new discoveries. There is always something we have passed unnoticed.

Natural history questions or topic suggestions can be directed to Ranger Steve (Mueller) at odybrook@chartermi.net – Ody Brook Nature Sanctuary, 13010 Northland Dr. Cedar Springs, MI 49319 or call 616-696-1753.