What Does an El Niño Summer Mean for Trees in Sydney?
An El Niño summer usually brings warmer, drier weather, which puts trees under more stress: more heat, less water in the soil and a higher chance of dead wood letting go. It is a likelihood, not a guarantee, because El Niño is only one of several things that shape Sydney’s weather.
The Bureau of Meteorology describes a strong El Niño that is still intensifying and expected to last into autumn 2027. It is also clear that a strong signal in the Pacific does not necessarily mean strong impacts on Australia. I would not panic, but I would plan, because being ready for a hard summer that turns out mild costs you very little.
For trees, three pressures matter most:
- Heat: long hot spells raise a tree’s water demand and add stress.
- Dry soil: less rain means stressed roots, thinning canopies and dieback.
- Fire season: dead wood, dry leaf litter and branches over the roof all add fuel close to the house.
How Can You Tell If a Tree Is Struggling in the Heat?
A struggling tree usually shows it in the canopy first: dead branches, thinning foliage, early leaf drop or leaf tips browning. Cracks in the trunk, fungal growth near the base and a new or worsening lean are more serious, and worth an arborist’s eyes sooner rather than later.
Signs to look for:
- Dead branches or bare patches in the upper canopy
- Early leaf drop, wilting or leaves browning at the tips
- Cracks, splits or cavities in the trunk or main limbs
- Fungal growth or soft wood near the base
- Soil cracking or lifting around the roots
- A new lean, or a lean that looks worse than last year
Start with large trees within falling distance of your house, driveway, fences or a neighbour’s roof. Mature eucalypts, trees that have dropped limbs in past storms and any tree already in decline move to the top of the list in a hot, dry season. After a hot spell we often get calls about large limbs that came down on a still afternoon from trees that looked perfectly healthy, which is why a quick check now is worth the time.
A photo can help me spot an obvious problem, but it is no substitute for a site visit. If something worries you, a tree risk assessment tells you which trees are sound, which need work and whether anything is a real risk to people or property. Our tree care team can plan the work from there.
How Should You Water and Mulch Trees in a Dry Summer?
In dry weather, the NSW Government’s advice is to water the ground from the base of the trunk out to where the branches stop, and to keep mulch clear of the trunk. Water slowly so it soaks in rather than running off, and mulch the same area so the soil holds on to that moisture for longer.
For mulch, the International Society of Arboriculture recommends a layer about 5 to 10 centimetres deep, spread out to the dripline where practical, and kept near but not touching the trunk. Coarse mulch such as arborist wood chips is a better choice than fine material. Piling mulch up against the trunk, sometimes called a mulch volcano, does more harm than good because it keeps the bark damp and can encourage decay.
Newly planted trees are a different case. NSW Government guidance is to water them regularly for the first six weeks, giving a thorough soaking rather than frequent light watering, and to keep up regular watering for the first two growing seasons.
Timing matters too. Research on mature urban trees through Melbourne’s long drought, published in Arboriculture & Urban Forestry, found that summer drip irrigation delivered only a fraction of what large trees needed, while watering before the growing season recharged the soil far more effectively. I read that as a reason not to wait for a heatwave: if the ground under a large tree is already dry, a good soak now is worth more than trying to catch up in January.
Check the rules before you water. Sydney Water’s Water Wise Guidelines apply all year, and tighter restrictions can come in if the dry weather drags on, so look at Sydney Water’s current rules before you set up a hose or sprinkler.
One limit worth knowing: water will not fix a tree that is structurally unsound. If a tree has cracks, a cavity or a lean, watering it better will not make it safe.
Which Tree Work Should You Do Before Summer, and What Can Wait?
Light, targeted work is worth doing before summer: removing dead wood and limbs that hang over roofs, gutters and paths. Heavy canopy reduction and major reshaping are better left to cooler weather, because stripping foliage from a tree that is already short of water adds stress.
Worth doing now:
- Removing dead wood and crossing branches
- Clearing limbs over roofs, gutters and paths
- Booking an assessment for any tree that worries you
- Checking council rules and lodging any application early
Better left until it cools down:
- Heavy canopy reduction
- Major reshaping of a tree that is already stressed
Urgent safety work is the exception, and it should never wait for a better season.
Deadwooding matters more in a hot, dry year, because dead limbs are the ones most likely to come down in a storm and the first to burn in a fire. Good pruning follows AS 4373, the Australian Standard for pruning of amenity trees, and takes off only what the tree can afford to lose. If a big reduction is needed, I would rather do the safety work now and schedule the rest for cooler weather.
Our tree pruning service covers dead wood removal, clearance over roofs and paths, and planned crown work. Significant pruning can need council approval, so read the council section below before any work starts.
What Does Bushfire Season Mean for Your Trees?
The Bush Fire Danger Period for most of NSW starts on 1 October, so dead wood, branches over the roof and canopies that touch near the house are worth dealing with now. Fire preparation is a separate job from general summer tree care, and I cover it in full in a dedicated guide.
My pre-season checklist, how far trees should sit from a house and how the 10/50 rule works are all in our guide to preparing your trees for bushfire season. The short version is that it is nearly always a prune, not a removal.
Hedges close to the house count too. Dead growth and dry leaves build up inside dense hedges, and clearing that out is a sensible fire-season job. Our hedge trimming service can take care of it.
Do You Need Council Approval to Prune or Remove a Tree in Sydney?
Whether you need approval depends mostly on your local council’s development control plan, which sets which trees are protected by species, size or location. The rules differ from one council to the next, so check yours before any significant pruning or removal.
The NSW Government’s framework, Chapter 2 of the Biodiversity and Conservation SEPP 2021, lets councils decide what needs a permit. The Department of Planning explains this on its vegetation in non-rural areas page, and our council regulations page is a good starting point for your area.
Removal should be the last option, not the first. Most stressed trees recover with the right care, and a healthy canopy keeps your house and garden cooler. Removal becomes the right call when a tree is dead, structurally failing or too close to a building to be made safe, and dead trees near a house are a particular concern in fire season. If a tree has to come down, our tree removal service can help, and a tree removal justification report can support your application where council asks for one. If you are left with an old stump after a removal, our stump grinding service can take it below ground level.
What Should You Do Before Summer Storms Arrive?
Heat-stressed and dry-weather-weakened trees can drop limbs when summer storms hit, so have large trees near the house checked before storm season and clear dead limbs over roofs, driveways and play areas. If a tree does fail, stay well clear and call for help rather than tackling it yourself.
Before storm season:
- Have large trees near the house checked for structural defects
- Remove dead limbs over roofs, driveways and play areas
- Keep gutters clear of leaves and twigs
Leave branches near powerlines alone. In Ausgrid’s network area, homeowners cannot trim within three metres of powerlines, and the work must be done by workers accredited to work near overhead electric lines. See Ausgrid’s tree trimming responsibilities page, or contact your own network operator if you are outside Ausgrid’s area.
If a tree or limb comes down, stay away from it and from any powerlines it may have brought down. Call 000 if anyone is in danger, or the NSW SES on 132 500 for storm help, such as a tree blocking your driveway or threatening your house. Once the area is safe, our emergency tree removal team can assess and clear it.
FAQs About Summer Tree Care in Sydney
Will El Niño affect my trees in Sydney?
It can, but it is a likelihood rather than a certainty. El Niño usually means a warmer, drier summer, which stresses trees through heat and dry soil, but the Bureau of Meteorology notes that a strong El Niño does not necessarily mean strong impacts on Australia. The sensible move is to check your large trees now and plan for a hard summer.
When should I start preparing my trees for summer?
Now. October and November leave time to book an assessment, lodge any council application and finish the work before the heat and the holiday shutdown. Waiting for a heatwave or a storm narrows your options.
Do I need council approval to prune a tree before summer?
Often, for significant pruning or for removing a protected tree. Some councils allow limited pruning without approval, but the thresholds differ across Sydney, so check your council’s tree rules or ask an arborist before work starts.
Can a drought-stressed tree recover?
Many can if the stress is caught early. Slow, thorough watering under the canopy, mulch kept clear of the trunk and removing dead wood all help. An arborist can tell you whether a tree is recovering or declining.
Is it safe to prune a tree during a heatwave?
I would avoid anything beyond urgent safety work. Cutting off a lot of foliage in extreme heat exposes bark and leaves to scorching and adds stress to a tree that is already short of water. Light pruning in spring or on cooler days is safer, and a good soak afterwards helps.
Tree Removal Rules in NSW May Be Changing
The NSW Government is considering changes to its tree clearing rules under a proposal called Protecting our trees. As at 6 October 2026 it is still a draft, with final amendments proposed for the second half of 2026. The proposals include higher penalties, replanting as a condition of permits and tighter exemptions for dead, dying or imminent-risk trees, which matters if you are thinking of removing a dead tree before summer. You can read the details on the NSW Planning Portal. Please check with your council before any work, because the rules may have changed by the time you read this.
If you would like a second pair of eyes on your trees before summer, contact our team to book an on-site assessment.
Disclaimer: This article is general information based on Arbor Pride’s professional experience and is not a substitute for a site-specific assessment. Tree health, safety risk, and legal requirements, including council permits and Tree Preservation Orders, vary by property, tree, and council area, and can change over time. Always arrange an on-site consultation with a qualified arborist and confirm current requirements with your local council before removing, pruning, or otherwise working on a tree.
About the Author
Julian Parry is the founder and managing director of Arbor Pride, with more than 20 years’ experience in arboriculture, and he still gets a kick out of watching a well-cared-for tree thrive. He’s a qualified arborist and horticulturalist holding Australia’s highest arborist rating, AQF Level 5 Consulting Arborist, and is a member of Arboriculture Australia, the Tree Contractors Association of Australia and the International Society of Arboriculture. Julian’s philosophy has always been preservation before removal, and he leads a fully insured team, backed by $20 million public liability cover, delivering everything from tree care and removal to arborist reports like tree risk assessments and tree protection plans for councils, schools and developers across Sydney’s North Shore. That approach has earned Arbor Pride 300+ five-star reviews and long-standing partnerships with councils and businesses across Sydney, and you can read more about our work on the Arbor Pride homepage.
