Ganoderma applanatum -- Fungus invades tree through wounds, several fungal diseases, sometimes called heart or sap rots, cause the wood in the center of trunks and limbs to decay. Under conditions favoring growth of certain rot fungi, extensive portions of the wood of living trees can decay in a relatively short time (months to years). This significantly reduces wood strength and kills sapwood storage and conductive tissues. Almost all species of woody plants are subject to trunk and limb decay. 
 

Fungal & Decay on Trees  

Fungal conks - brackets  --  the outer sign of substantial sap wood and heart rot