Debbie McDonald
Summarized from Douglas W. Tallamy’s book, The Nature of Oaks.
By the time March arrives most oak leaves have fallen to create a lovely organic layer under the canopy and are awaiting their turn to be composted by an abundance of little creatures, perhaps millions, that eat dead leaves instead of green leaves and, along with other unseen creatures and their predators, create a complex community of decomposers. For example, in a single square meter of leaf litter you might find more than 100,000 springtails or 250,000 mites or 1 million nematodes. While most are not visible to the naked eye in all that leaf litter, you can do a little experiment. Scrape away a top layer of leaves and place a sheet of white paper in the spot. After a few minutes your paper will be dotted with whatever species happen to find the paper in their path.
Oak leaves are full of nutrients derived from the sun and are only made available for new plant growth by recycling all those nutrients, which is the job of decomposers. Oak leaves tend to decay very slowly once on the ground and, because the litter is replenished yearly, there are always leaves in various stages of decay (provided you don’t do something to break the cycle such as raking or burning.) Most other deciduous trees have thin leaves that decay quickly once shed by their tree. Decomposers cannot survive for long on or in soil that is not covered by leaf litter. By leaving the oak leaves in various stages of decay, decomposers are provided with housing, food, and humid conditions for up to three years. Any leaf pack with a substantial proportion of oak leaves protects the ground and the diverse inhabitants year round.
Oak forests with deep litter also protect against certain invasive species, both plants and pests. Litter also improves water filtration, acting like a sponge and holding water long enough to seep into the ground replenishing the water table and purifying by filtering out excess nitrogen and phosphorus from fertilizers as well as heavy metals, pesticides, oil, and other pollutants.
Tallamy is convinced that oaks are the most essential native tree in the world, and with each monthly chapter in his easy-to-read book he shares what is happening outside our doors in and under the oaks of High Prairie.