Most tree problems cost significantly less to address early than to deal with after a failure. These are the signs to act on.
Structural warning signs in trees are not always immediately obvious, but there are visible indicators worth knowing. Cracks in the main stem or major branches — particularly longitudinal cracks running along the grain of the wood — indicate stress fractures that can lead to sudden failure under wind load or the weight of wet foliage. Co-dominant stems, where two trunks of roughly equal diameter join at a narrow included-bark union, are a known failure point and are common in many exotic species found on Bay of Plenty lifestyle blocks. Canopy dieback on one side of a tree, or significant asymmetry in leaf density, can indicate root damage, vascular disease, or a structural problem restricting water and nutrient flow to part of the crown.
Disease and Decay — What to Look For
Fungal fruiting bodies growing from the base of a tree, from the root zone, or from wounds on the main stem are a strong indicator of internal decay. The visible mushroom or bracket is only the reproductive stage of a much larger fungal structure that has been colonising the wood for months or years before it surfaces. Not all fungi indicate the same level of risk — some are associated with surface-level sapwood decay that weakens the tree gradually, while others cause rapid breakdown of structural heartwood. An arborist can usually identify the genus from the visible fruiting body and give you a reasonable assessment of how advanced the internal decay is likely to be.
After Storm Damage — When to Call Immediately
After significant storm events — common in the Bay of Plenty during the summer severe weather season — trees that have not visibly fallen can still be structurally compromised. Root plate disturbance from high winds may not be apparent above ground immediately after the event. A slight lean that was not there before, soil heaving around the base, or new cracks in previously intact bark can all indicate that root anchorage has been partially disrupted. A tree in this condition may remain standing for months or years, but is at significantly higher risk of failure in the next major wind event than it was prior to the storm.
Root Zone Problems That Point to Hidden Risk
Root zone problems are often overlooked because the roots are underground. Changes at ground level, however, can reveal what is happening below the surface. Lifting or cracking of paving, paths, or lawn near the base of a tree can indicate aggressive surface rooting in some species, but it can also mean the tree has lost deeper anchorage and is relying increasingly on lateral surface roots for stability. Construction work, soil compaction, trenching for services, or changes in drainage patterns within the root zone can damage fine feeder roots and weaken a tree years before any above-ground symptoms become visible.
Not every concern about a tree requires immediate action — but some do. A tree with an active basal fungal infection adjacent to a structure, a co-dominant stem positioned over a driveway or outdoor living area, or significant post-storm lean near a building warrants prompt professional attention. Delaying in these cases does not reduce risk — it increases it, because the underlying conditions generally worsen progressively rather than stabilising or resolving on their own.
Wahitapu Contracting provides tree risk assessments across the Western Bay of Plenty. If you have a tree you are concerned about, call Kauri on 027 600 0446. A site assessment will give you a clear, honest picture of the actual risk level and the options available, without pressure to spend more than the situation genuinely warrants.