At LundinTree, we know this simple truth: Healthy trees start with healthy soil. You can water, prune, and fertilize all you want, but if the soil beneath your trees isn’t alive and thriving, your trees won’t be either!
Whether you’re maintaining a mature oak, planting a new sugar maple, or landscape, the health of the soil beneath your feet determines how strong and sustainable your trees will be in the long term.
Soil Is Alive and That’s a Good Thing
Healthy soil is more than dirt. It’s a living, breathing ecosystem packed with organisms working together to support your trees:
- Bacteria help break down organic matter and convert nitrogen into forms trees can absorb.
- Fungi (especially mycorrhizae) form symbiotic relationships with tree roots, expanding their reach and boosting water and nutrient uptake.
- Nematodes and protozoa feed on other microbes, keeping populations in balance and cycling nutrients back into the soil.
- Earthworms aerate the soil and enrich it with castings.
This underground community—often called the soil food web—plays a critical role in tree health. If your soil is compacted, sterile, or overloaded with synthetic inputs, those microbes can’t survive—and your trees will struggle.
The Right Moisture Matters
Moisture is key, but it has to be balanced. Over watering can suffocate roots due to anaerobic conditions, while under watering can lead to drought stress and root death.
- Too little moisture: Soil dries out, microbial life declines, roots become brittle, and trees may loose ability to uptake water and nutrients
- Too much moisture: Waterlogged soil drives out oxygen, encourages root rot, and can lead to changes in pH of the soil
Tips for maintaining proper soil moisture:
- Water deeply once or twice a week, rather than daily sprinkles.
- Use a slow-drip system or tree watering bag to avoid runoff
- Test moisture with a narrow stick or moisture meter: if it penetrates easily, no need to water.
- Avoid compacting the soil around trees by walking or parking on roots
Mulch… A Microbial Magic & Moisture Control
Mulch isn’t just about making your beds look tidy, it’s a vital part of soil health. A good mulch layer provides:
- Moisture retention (critical for root and microbial life)
- Temperature regulation (protecting roots from extreme temperature swings during hot summers and frigid winters)
- Organic matter as it breaks down, feeding microbes and enriching the soil
- Protection from mower and trimmer damage to the trunk flare
How to Mulch the Right Way:
- Use 2–3 inches of shredded bark or wood chips
- Spread mulch in a wide, even donut shape around the tree
- Keep mulch 4–6 inches away from the trunk to prevent rot
Common Mulch Mistakes to Avoid:
- “Mulch volcanoes” around tree trunks (which promote rot and pests)
- Using plastic or synthetic fabric under mulch (prevents air and water exchange)
- Applying more than 3–4 inches deep (can smother roots)
Soil and Tree Health Go Hand-in-Hand
At LundinTree, we don’t just look at leaves and limbs—we look at what’s happening below the surface. Whether we’re planting a new tree, responding to storm damage, or performing a risk assessment, we check:
- Soil structure: Is it compacted or loose? Has the root plate shifted or heaved?
- Moisture levels: Is there enough water available to the plant?
- Organic content: Is there mulch? Is the soil “alive” is it loose and vibrant or compacted and dead?
- Root zone health: Is the root flare visible, healthy, and growing outward?
We often recommend mulching, compost top-dressing, or root-zone aeration to improve soil biology and give trees the best chance to thrive.
Let Your Soil Work for You
Whether you’re caring for backyard ornamentals, large shade trees, or newly planted saplings, one of the best investments you can make is in your soil.
When your soil is alive and well, your trees grow stronger, resist pests, bounce back from storms, and look better year-round. When it’s neglected, everything above ground eventually suffers.
