Ladies and gentlemen. Before I plant the tree I think I shall talk a little. It’s very difficult for me to know exactly where my audience is. Now a gentleman tells me I am to face this way because these gentlemen who are operating have of course gone to the wrong side. They always do…”

my question: As shaw says this, audience bursts into laughter? Is this that funny?

I did not comprehend most funny part of this....

my best wishes for those who spend time for me.
Doesn't make any sense.
Who is speaking? What does the audience look like?
Students: We have free audio pronunciation exercises.
Bernard Show who is irish writer.
He speaks, about a kind of ceremony for planting tree.

What is the name of the play or book that this quote is from?
not from a play, as I stated before it is come from a speech delivered at ceremonial tree planting.
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enkiduIs this that funny?
Apparently you had to be there.