Oak Ridges Moraine tree removal: what King Township, Aurora, and Richmond Hill homeowners need to know

Background

What the Oak Ridges Moraine is — in plain language

The Oak Ridges Moraine is a 160 km glacial-era ridge that runs east-west across south-central Ontario, from Trenton in the east to the Niagara Escarpment in the west. It was deposited during the last glaciation about 13,000 years ago and forms one of the highest pieces of land in southern Ontario.

Why it matters: the Moraine is the source of more than 65 rivers and streams flowing into Lake Ontario and Lake Simcoe, the primary recharge area for the aquifers that supply much of the GTA's groundwater, and home to remnant Carolinian-zone and mixed-hardwood forest fragments. It's the ecological reason much of King Township and northern Aurora look the way they do — long stretches of treed countryside with horse properties, conservation easements, and large estate lots rather than the dense suburban grid you see south of Highway 7.

Since 2001 the Moraine has been protected under the Oak Ridges Moraine Conservation Plan, a provincial land-use plan administered by the Ontario Ministry of Municipal Affairs and Housing. Tree removal on Moraine land is subject to the Plan's restrictions, in addition to whichever municipal tree by-law applies.

The four Moraine designations

Every property within the Moraine boundary falls under one of four land-use designations, in decreasing order of protection:

Natural Core

The most protected designation. Natural Core areas are primary natural-heritage features — old-growth forest fragments, headwater wetlands, significant woodlots. Removal of healthy trees in these areas usually requires an Environmental Impact Study (EIS) by a qualified ecologist. Standard timeline 4-8 weeks. Replacement plantings with native species are almost always required, and the replacement ratio may exceed one-for-one.

Natural Linkage

Corridors connecting Natural Core areas, providing habitat continuity for wildlife. Restrictions are slightly less strict than Natural Core but still significant. TRCA consultation usually required for any substantial tree removal. Native species preferred for replacement.

Countryside

Working agricultural land and rural-residential parcels that fall within the Moraine boundary but are not part of the ecological core network. The municipal tree by-law applies; the Moraine overlay is lighter. Most rural Kettleby, Pottageville, Lloydtown, Snowball, Schomberg, and Nobleton properties fall in Countryside.

Settlement

Existing town and village cores within the Moraine boundary. King City village core, Schomberg core, and Nobleton core are Settlement areas. Standard municipal by-law review only — no Moraine overlay. If your property is in the village proper rather than rural-zoned acreage, you're likely in Settlement and the process is the same as anywhere else in the municipality.

When TRCA consultation is required

The Toronto and Region Conservation Authority (TRCA) administers conservation regulations across the watersheds in Aurora, King Township, Richmond Hill, Whitchurch-Stouffville, and surrounding areas. TRCA consultation is required for tree work on properties within regulated areas:

• Natural Core and Natural Linkage Moraine designations. Almost always.
• Valleylands. Properties within or adjacent to ravine systems.
• Wetlands. Including provincially significant wetlands and the buffer zones around them.
• Watercourses. Properties bisected by or adjacent to streams, rivers, ponds.
• Floodplains. Regulatory flood-line areas.

Standard TRCA consultation timeline: 2-4 weeks. We file the TRCA submission as part of the quote scope on affected properties — you do not handle it directly. We tell you up front when scoping the job whether your property requires TRCA review and how that affects the overall timeline.

How the Greenbelt Plan layers on top

The Greenbelt Plan is a broader provincial land-use framework covering about 2 million acres across the Golden Horseshoe, from the Niagara region to Northumberland County. The Oak Ridges Moraine is a designated component of the Greenbelt — Moraine rules layer on top of Greenbelt rules.

For most residential tree-removal cases, the Moraine designation is the controlling restriction; the Greenbelt overlay rarely adds incremental requirements at the residential property level. Larger commercial scope or development applications on Greenbelt land have additional provincial review steps that do not apply to typical residential tree work.

Municipal by-laws that apply on the Moraine

The Moraine crosses multiple municipalities. Each has its own private-tree by-law:

• King Township By-Law 2017-49. Permit threshold 30 cm DBH in rural-zoned areas; 20 cm in residential zones. More on King Township tree work.
• Town of Aurora By-Law 6362-21. Permit threshold 20 cm DBH. Applies to the small portion of Aurora north of the Moraine boundary. Full Aurora permit guide.
• Richmond Hill By-Law 41-07. Permit threshold 20 cm DBH. More on Richmond Hill tree work.
• Whitchurch-Stouffville By-Law 2009-87-LR. Permit threshold 25 cm DBH.
• Caledon By-Law 2009-061. Permit threshold 20 cm DBH.
• Uxbridge By-Law 2014-018. Permit threshold 30 cm DBH.

Approved native replacement species for Moraine properties

Townships typically reject non-native or invasive species for Moraine replacement plantings. Approved species adapted to USDA zone 5b conditions in the Moraine region include:

• Sugar maple (Acer saccharum) — the iconic Carolinian-zone hardwood
• Red oak (Quercus rubra) and white oak (Quercus alba) — long-lived, drought-tolerant once established
• Eastern white pine (Pinus strobus) — Ontario's provincial tree, fast-growing native conifer
• Eastern hemlock (Tsuga canadensis) — shade-tolerant evergreen, good for understory and shaded north slopes
• Ironwood (Ostrya virginiana) and American beech (Fagus grandifolia) — native understory hardwoods
• Basswood (Tilia americana) — large native shade tree, important for pollinators
• Serviceberry (Amelanchier spp.) — small native ornamental, spring flowers and fall colour
• White spruce (Picea glauca) and red maple (Acer rubrum) — common native replacements

Avoid Norway maple (Acer platanoides, invasive), tree-of-heaven (Ailanthus altissima, invasive), Manitoba maple (Acer negundo, often classified invasive in southern Ontario), Siberian elm, and any non-native ornamentals not on the local approved list.

Hazardous-tree exemptions still apply

The municipal by-law's hazardous-tree exemption applies on Moraine land the same as elsewhere — a tree that poses imminent risk to people or structures can be removed without prior permit. However, documentation requirements are stricter:

• Photographs from multiple angles before removal
• ISA-certified arborist condition assessment, written
• (In Natural Core areas) brief explanation of what makes the tree hazardous
• Town/Township notification within 7 days of removal
• Photographs of the stump and root structure after removal can support the documentation

Emergency post-storm exemptions also apply, with the same 7-day notification requirement. We document carefully on every Moraine job — emergency or otherwise. See our step-by-step process guide for how documentation flows through the permit and exemption paths.

Tree on a Moraine property? Get a quote.

We pull your property's Moraine designation and (if applicable) TRCA regulated-area status during scoping. The written quote includes by-law permit handling, TRCA submission if required, replacement-species recommendations, and an honest estimate of the timeline impact of conservation review. No high-pressure in-person visits.

Get a free written quote within 24 hours

Sources

• Oak Ridges Moraine Conservation Plan (provincial regulation O. Reg. 140/02 under the Oak Ridges Moraine Conservation Act)
• Greenbelt Plan (2017, updated 2024)
• Toronto and Region Conservation Authority (TRCA) (consultation requirements for regulated areas)
• King Township By-Law 2017-49
• Town of Aurora Private Tree By-Law 6362-21
• International Society of Arboriculture (ISA) (arborist certification standard)
• Ontario.ca — native tree species

This guide is reviewed quarterly against Moraine Conservation Plan amendments, TRCA regulation updates, and municipal by-law changes. Last full source check: 2026-05-26.