The site work division of ICFHome.ca · Building since 1979 · Insured to $2,000,000 · 705-533-1633
Trees and Building2026Tiny, Tay, Midland, Wasaga, Collingwood
Which Trees to Keep When You Build
Keep healthy trees that sit well outside the house, driveway and septic footprint, with their root zone fenced off and the grade under them left alone. Trees right at the edge of the dig, trees on a new grade, and tall pines suddenly left standing alone on sand are usually better taken now, while the machines are on site. Here is how we decide, tree by tree, on a typical Georgian Bay lot.
Updated October 2026 · Georgian Bay Siteworks, the site work division of ICFHome.ca
Insured to $2,000,000Site work division of ICFHome.caBuilding since 1979250+ projects in Simcoe County
The Hard Part: Trees Die Slowly
A tree damaged during construction does not fall over the week you move in. Purdue Extension’s construction guidelines say it can take years for damaged trees to show symptoms. By then the excavator is long gone and the tree is 6 m from your new roof.
So the question is not “can this tree survive the build?” It is “will this tree still be healthy in five years, and if it is not, what will it cost to take down then?”
Builder truth: during clearing, one more tree is a few minutes of machine time. After the house is up, the same tree is a separate removal in the $800-$3,000 range, done carefully around your new siding.
Trees Worth Saving
Healthy hardwoods with room
Sound oak and maple with a full crown, sitting well clear of the dig. These give shade, wind cover and resale value, and they are worth protecting properly.
Groups, not singles
A clump of trees left together holds each other up and shelters each other’s roots. A single survivor in an open lot takes the full wind on its own.
Screening along the lot lines
A strip of existing trees along the side lot lines gives privacy you cannot buy at a nursery for years. Mark it before clearing starts.
Young, vigorous trees
Purdue notes younger trees handle root disturbance better than mature or declining ones. A healthy 20 cm maple may outlast a stressed 60 cm one.
Trees We Usually Recommend Taking
- Anything inside the dig line. Foundations, septic beds and service trenches cut roots on one whole side of the tree. A tree within a few metres of the excavation rarely does well.
- Tall pines left alone on sand. Near the Bay, most lots are sand with a high water table, and pines root shallow in it. When you clear around them, the trees at the new edge take wind they never had to handle. Even general forestry references note that removing trees at an edge increases wind exposure on the ones left. A 25 m pine falling toward a new house is a bad day.
- Trees where the grade changes. If the lot grading plan raises or lowers the ground under a tree, it is probably a goner. More on that below.
- Dead or dying ash. They go brittle and get harder and more expensive to drop every year.
- Trees over the septic bed or tank area. Roots chase water and wreck distribution pipes, and the bed needs sun and open grass. See our landscaping over a septic bed guide.
- Trees in the driveway turning radius. Delivery trucks and concrete trucks will clip them, and the compaction from loaded trucks kills roots anyway.
How Much Root Zone a Tree Needs
Roots spread wide and shallow, often past the outer edge of the branches. Purdue’s guidelines set a protected root zone of 1.5 feet from the trunk for every inch of trunk diameter, measured at chest height. That is a big circle.
| Trunk diameter | Protected radius (Purdue rule) | What it means on a lot |
|---|---|---|
| 8 in (20 cm) | 12 ft (about 3.7 m) | Easy to fence off on most lots |
| 16 in (40 cm) | 24 ft (about 7.3 m) | Needs real room from the house and trenches |
| 24 in (60 cm) | 36 ft (about 11 m) | Hard to protect on a small waterfront lot |
Purdue says not to let more than 25 percent of the roots inside that zone be damaged. If the house, the bed or the well line cuts through more than a quarter of the circle, plan on that tree coming out.
What Kills Kept Trees
- Fill over the roots. Purdue says as little as 2 inches of fill over the root zone can potentially kill a tree. A lot grading plan that raises the yard 300 mm around a maple is a death sentence for the maple, just a slow one.
- Cutting the grade down. Lowering the ground under a tree scrapes off the feeder roots. Same result.
- Compaction. Parking the excavator, the lumber pile or the concrete truck under a tree crushes the soil the roots breathe through.
- Trenching. A hydro or water trench across the root zone cuts the tree off on one side.
- Washing out the concrete truck. It happens. Fence the trees so it happens somewhere else.
What We Do on Site
Before clearing, we walk the lot with you and the site plan and flag every tree that stays. Keepers get a fence at the drip line or wider, and that fence stays up until final grading. Nothing gets parked, piled or dumped inside it.
We route the driveway, the hydro trench and the well line around the keepers where the site plan allows. Where a keeper sits in a spot the grading plan has to raise, we tell you before the fill goes in, not after. Trees that come out can go on our portable sawmill if the logs are good, so the oak you lost for the garage may come back as the mantel.
And if you are still choosing where the house goes, tell us early. Shifting a house 3 m on paper can save the best tree on the lot. Shifting it after the footings are poured cannot.
Walk the Lot With Us Before Anything Gets Cut
Send your site plan or survey. We will flag the keepers, the risky ones and the ones that have to go, and price the clearing in writing.
Related guides
Frequently Asked Questions
How far from the house should a tree be to keep it?
Far enough that the excavation, trenches and new grade stay out of its root zone. Purdue’s rule of thumb is a protected radius of 1.5 feet for every inch of trunk diameter, so a 16 inch tree needs about 24 feet.
Can I keep a tree if the grade is being raised around it?
Usually not. Purdue says as little as 2 inches of fill over the root zone can potentially kill a tree, and grading plans often raise yards far more than that.
Why are tall pines on sandy lots risky to keep?
Pines on sand near the Bay often root shallow, and once you clear around them they take wind they were never exposed to. A lone tall pine near a new house is one we usually recommend taking.
How long until a construction-damaged tree dies?
It can take years. Purdue says damaged trees may take years to show symptoms, which is why decline often shows up after you have moved in.
Should trees be kept near the septic bed?
No. Roots go after the water in the bed and can plug distribution pipes, and the bed needs sun and grass. Trees near the tank and bed are ones we take during clearing.
Is it cheaper to remove a tree during clearing or later?
During clearing, by a wide margin. With machines already on site it is minutes of work, while a later removal next to a finished house is a separate job, often $800-$3,000 or more.
