Here's a longer version with a slightly different story. I can appreciate why it was somewhat truncated by Baez.

THE RIVER IN THE PINES

Oh Mary was a maiden when the birds began to sing
She was fairer than the blooming rose so early in the spring
Her thoughts were gay and happy, in the morning gay and fine
For her lover was a river-boy from the River in the Pines

Now Charlie got married to this Mary in the spring
When the trees were budding early and the birds began to sing
'Now darling I must leave you in the happiness of love
And make some Vs and Xs for you, my darling dove
And early in the autumn when the fruit is in the wine
I'll return to you, my darling, from the River in the Pines

'T was early in the morning in Wisconsin's dreary clime
When he rode the fatal rapids for that last and fatal time
They found his body lying on the rocky shores below
Where the silent water ripples and the whispering cedars blow

The woodsmen gathered round him on the bright and cloudless morn
And, with sad and tearful eyes, they viewed his cold and lifeless form
'I would send a message to her, but I fear she would repine',
Spoke a friend of Charlie Williams from the River in the Pines

When Mary heard these tidings from that river far away
In was in the early springtime, in the early month of May
At first, she seemed uncertain and no more her eyes did shine
But her saddened thoughts still wandered to that River in the Pines

Not long ago, I visited there, not many years ago
It was a southern city where strange faces come and go
I spied a grey-haired maiden, both very old and grey
And my thoughts turned back again once more to that river far away

She smiled, though, when she saw me, though she looked old and grey
'I am waiting for my Charlie boy', these words to me did say
And early in the autumn when the fruit is in the wine
I'll return to meet my Charlie from the River in the Pines

Now every raft of lumber that comes down the Chippewa
There's a lonely grave that's visited by drivers on their way
They plant wild flowers upon it in the morning fair and fine
'Tis the grave of Charlie Williams from the River in the Pines

Source: From Franz Rickaby (Coll and ed) 'Ballads and Songs of the Shanty-Boy' Cambridge Harvard University Press 1926. This is song #30 in Rickaby's collection, sent to him by Mr William Bartlett, Eau Claire, Wisconsin.

--Stewie.