LELE leaf mulching, when done with appropriate equipment and easy-to-learn techniques, results in very finely shredded leaf mulch. This is not what is termed in the scientific literature as “leaf litter.” Leaf litter consists of piles of whole leaves, typically found under trees and/or at yard margins such as along a fence, wall, or foundation. Leaf litter may be an attractive home to ticks.
While there are no specific studies yet published on the impact of LELE practices on tick populations in suburban lawn areas, the available research allows one to reasonably conclude that there should be no increase in tick populations due to the fine mulching/shredding of leaves. In fact, population reduction would be expected. One important factor leading to this conclusion is that shredded leaves differ significantly from whole leaves since they provide a micro-environment that is lower temperature and humidity, thus an environment less hospitable to ticks.
The recommended LELE practice of leaving leaves alone in wooded areas should not cause any increase in ticks: the net impact will not be significantly different from naturally occurring levels. Other environmental factors including rodent population levels and acorn crop density will have a more direct effect on increased tick populations. Because of this, composting mulched leaves and/or grass clippings along with food waste, if undertaken by the homeowner, should be carefully monitored for rodent attraction.
Note also that there has been reports of a greater density of ticks in leaf litter under Barberry shrubs.
Read more background - what we know about ticks - an interview with Dr. Rick Ostfeld of The Cary Institute.
Final thoughts from a sustainability perspective:
What LELE practices provide at their heart is the low-cost restoration of a natural waste management cycle back into the landscape, by allowing the nutrients locked up into leaves to be re-cycled into the soil (on lawns or in garden beds). By the simple technique of finely shredding such leaves, the breakdown and decomposition of said materials occurs at an accelerated rate. Soil quality, water retention, and plant health are all improved.
Complete removal of leaves from properties, suggested by some as a solution to ticks, actually robs both your soil and plants of much needed nutrients and micro-nutrients, and incurs associated costs in higher erosion, loss of biodiversity, damage to roots and re-generating seedlings, and disruption of natural aesthetics.
Read a more detailed analysis surveying some available tick research in this context.