Is the question asked in the second line answered? Not directly, though the answer is implied.
State the substantial meaning of the stanza. The "towering pine" of the Sierras tells of the disappearance of the mining camp; the "stately spire" of Kent tells of the death of Dickens; both bear witness to the potent influence of Dickens.
Stanza IX
What is the "fragrant story" of the Western mining camp? The tribute that the incident related in the poem pays to the magical power of Dickens as a story writer.
Why is it called a "fragrant story"? The author poetically conceives of it as being laden with the fragrance of the fir, the pine, and the cedar—a sort of "incense" to the memory of the "Master".
What is incense? The odours of spices and gums burned in religious rites.
What poetic idea does the author express in the last two lines? The hopvines of Kent are represented as uniting with the pine, fir, and cedar in sending forth their fragrance as incense.
What is the meaning, then, of the whole stanza? Let the fragrance of the pine, the cedar, and the fir, mingled with the odours of the Kentish hopvines, be as incense to the memory of the "Master".
Stanza X