Basal Cavities  - Cavities at the base of a tree are potentially dangerous if present between more than one pair of buttress roots

Canker  - Cankers can lead to a structural weakness of stems and branches

Cavities  - Decay may develop in wounds caused by branches breaking or poor pruning

Damaged roots  - Site disturbance may sever or kill roots. Site and soil conditions may lead to inhibited rooting. This could lead to the tree becoming unstable

Fungal fruit bodies  - Various fungi are positive indicators of internal decay. Fruit bodies on or near roots may indicate they are decayed, but the species of fungus requires identification, as many are harmless and beneficial.

Leaves (or needles)  Dead twigs and branches -  Generally small, sparse or pale. Tree flushes late or drops its leaves early. These symptoms are often an indication of root decay or death.

Loose bark - Loose bark may signify the presence of rotten wood beneath

Pollards  - Decay may exist but be hidden by regrowth

Pruning wounds - The wound surface may appear normal, but the wood behind may be decayed

Soil cracks  - Ground movement may occur when a tree with an unstable root system moves in strong winds

Weak fork  - Tight V-shaped crotches may be structurally weak giving rise to cracks. Decay and cavities can develop in these crotches