Opinion: Some lives depend on presence of leaf litter

By Mary Lou Flint

The loud, irritating sound of leaf blowers is ubiquitous in Curtis Park. Neighbors frequently complain about the noise, dust and carbon dioxide emissions from the gas engines that propel them.

But does anyone consider what all this leaf blowing is doing to the living parts of our ecosystem? What drives this urgent need to remove every leaf in a planting bed or from under every shrub and tree every week year-round?

Leaves, twigs and other plant material that fall naturally to the ground make up an important soil surface layer that scientists call leaf litter. Hundreds of organisms make their homes in leaf litter, all part of a complicated food web that breaks down organic matter, nourishes the soil and feeds a huge variety of animals from spiders, worms and beetles to song birds and frogs.

When you remove leaf litter on a regular basis, you destroy this ecosystem. Organic matter gives better structure to the soil and replenishes it with nitrogen, phosphorous and other minerals that plants need to grow. Leaf litter holds moisture, reduces soil compaction and erosion and moderates temperatures in winter and summer. It is natural mulch and free fertilizer.

Many organisms are essential to the proper functioning of the leaf litter ecosystem. A vast variety of bacteria, fungi, nematodes, worms, insects and other invertebrates work together to build a healthy, living soil. Springtails, mites, millipedes, earthworms, etc. break down leaves in concert with specialized fungi and bacteria. A host of predators such as beetles, spiders, ants, pseudoscorpions and centipedes are at the next level of the food chain, providing sustenance to birds and other animals and also natural biological control of insect pests on our landscape or food plants.

In my little corner of Curtis Park between 10th Avenue, Cutter Way and East Curtis Drive, we have a population of Pacific chorus frogs that sing loudly at night from January through summer. These tiny amphibians require water for their short tadpole stage, but spend most of their lives sheltering in leaf litter or thick plant growth. I would be sorry if the increasing use of leaf blowers silenced them.

If you remove the leaf litter every week, you lose all this, and the quality of your garden ecosystem suffers. What is wrong with a few leaves under your plants anyway? An inch or so of leaf litter is healthy and not unattractive. In fall or spring or anytime when leaf litter gets too thick, thin it, preferably by hand or with a small rake.

If you go in with a leaf blower, use a gentler electric one no more than every few months. The birds and frogs will thank you.

Mary Louise Flint is an extension entomologist emerita with the Department of Entomology and Nematology at UC Davis.

Written by Guest Author to Viewpoint and posted on Sunday, June 13th, 2021

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