How to Treat Damaged Prunus Tree?
During the storms earlier this year, my large Prunus tree split down the middle and one half pealed away onto my lawn, narrowly missing our conservatory. It had been weakened by Ganoderma fungus. The half that remains standing has been confirmed safe and significantly reduced in height but now has a large open cavity in the side of the main trunk at its base: see photo below.
The bottom of this cavity is bowl-shaded and extends below ground level - ideal for collecting rain water! It is also still full of spongy soft word from fungal attack. To prevent further damage from pooling water, should I (a) pick-out as much spongy wood at the bottom of the cavity as possible (which can be torn-off by hand!) to improve drainage and (b) then fill the bottom of the cavity with soil, up to the surrounding ground level?
Thanks in advance for any advice.