Cutting down a tree on a slope is one of the more hazardous DIY tasks a homeowner can attempt. The combination of uneven footing, unpredictable fall direction, and the risk of a rolling log makes slope felling significantly more dangerous than working on flat ground. For small trees in straightforward situations, a careful and well-prepared homeowner may manage safely — but for anything large, leaning, or near structures, calling a qualified arborist is strongly recommended.
Assess the Situation Before You Start
Before picking up a chainsaw, take time to properly assess the tree and site:
- Tree size and lean: Does the tree lean uphill, downhill, or sideways? A tree that leans downhill on a slope will want to fall faster and further than expected.
- Root condition: Sloped ground can mean shallow or eroded root systems, making the tree less stable during cutting.
- Surroundings: Identify hazards — fences, powerlines, structures, neighbouring properties, and public areas below the slope.
- Escape routes: On a slope, your footing is compromised. Plan two clear escape routes at roughly 45 degrees behind and to the side of the intended fall direction — never directly uphill or in the fall path.
- Ground conditions: Wet or loose soil on a slope dramatically increases the risk of slipping.
If there are powerlines anywhere near the tree, stop immediately and contact your lines company. Working near powerlines is extremely dangerous and may require them to de-energise the line first.
Tools and Personal Protective Equipment (PPE)
Never attempt tree felling without appropriate PPE:
- Chainsaw chaps or cut-resistant trousers
- Helmet with integrated face shield and hearing protection
- Cut-resistant gloves
- Steel-capped, ankle-supporting boots (especially important on uneven ground)
- High-visibility vest if working near a road or public area
WorkSafe NZ provides guidance on safe chainsaw use and PPE requirements that apply to homeowners and professionals alike.
Planning the Fall Direction
On a slope, the preferred fall direction is generally across the slope (perpendicular to the slope's fall line), rather than straight downhill. Here's why:
- Felling straight downhill means the log can roll or slide a long distance, creating a serious hazard for anyone or anything below.
- Felling straight uphill is difficult and puts you in the fall path.
- Felling across the slope allows the tree to come to rest against the slope itself, reducing rolling distance.
Use felling wedges (plastic or aluminium) to help guide the fall direction and prevent the saw from being pinched. Never use steel wedges with a chainsaw.
The Felling Cuts
For a tree you've determined is safe to fell yourself, the standard three-cut method applies:
1. The Notch (Face Cut)
Cut a notch on the side facing your intended fall direction. The notch should be roughly one-quarter to one-third of the tree's diameter deep, with the two cuts meeting cleanly. On a slope, position yourself on the uphill side where possible for better stability and visibility.
2. The Back Cut (Felling Cut)
Made from the opposite side, slightly above the base of the notch. Leave a hinge of uncut wood — typically about one-tenth of the tree's diameter — to guide the fall. Never cut through the hinge completely before the tree begins to fall.
3. Retreat
As soon as the tree begins to move, turn off or release the chainsaw throttle, and move along your pre-planned escape route. Keep your eyes on the falling tree. On a slope, move uphill and to the side — never run downhill.
Managing the Log After Felling
Once the tree is down, the work isn't over. On a slope:
- Secure the log immediately with a rope, stake, or by bucking (cutting) it into shorter sections that won't roll.
- Work from the uphill side when bucking a log on a slope to avoid being struck if it moves.
- Be aware of tension and compression in the wood — a log resting on a slope can pinch your saw or kick unexpectedly when cut.
- Remove cut sections progressively, starting from the top (uphill end) of the log.
Do You Need a Building Consent or Council Permission?
In New Zealand, some trees are protected by district plan rules, heritage overlays, or resource consent conditions. Before felling any tree, check with your local council whether a resource consent or tree removal permit is required. This is especially relevant for large trees, trees in notable locations, or properties in certain zones. Felling a protected tree without consent can result in significant fines. Your council's planning team is the right first point of contact.
When to Call a Professional
Hire a qualified arborist for any of the following situations:
- The tree is large (generally over 20–25 cm trunk diameter at chest height, as a rough guide)
- The tree is dead, diseased, or structurally compromised
- There are powerlines, structures, or public areas in or near the fall zone
- The slope is steep (greater than roughly 20–25 degrees) or the ground is unstable
- The tree has a significant lean in an undesirable direction
- You are not experienced with chainsaw operation
- You feel uncertain at any point — trust that instinct
A qualified arborist has the training, equipment, and insurance to handle complex removals safely. You can find experienced local arborists on tradedirectory.co.nz.
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