How might the old chestnut tree in the grounds of Thornfield be used an example of symbolism in ‘Jane Eyre’?

The chestnut tree is where Rochester and Jane get engaged, and so it seems that initially it is a symbol of their strong bond. Trees are often used as a symbol of life and family (think growing and family trees etc.), so it seems to be a symbol of their new life as a family together. However, this symbolism becomes more complex when later that night the tree is struck by lightening and torn in two pieces, just as Jane's veil is torn in two before the wedding. These symbols function as bad omens, telling the reader that not all will be simple in their relationship and foreshadows the disastrous wedding. Eventually, Jane and Rochester are reunited and Rochester even compares himself to the tree ('I am no better than the old lightning-struck chestnut-tree in Thornfield orchard'), suggesting that he is damaged and ripped in two by all that he has done and all that has happened. Jane continues this image, but alters it to comfort him:

'You are no ruin, sir—no lightning-struck tree: you are green and vigorous. Plants will grow about your roots, whether you ask them or not, because they take delight in your bountiful shadow; and as they grow they will lean towards you, and wind round you, because your strength offers them so safe a prop.'

And so Brontë concludes this symbol of the tree, and perhaps suggests that it is a symbol of new life ('green and vigorous') after pain. Brontë may be suggesting that the couple have strong 'roots' and will 'grow' together because they have survived all that has happened to them.