Lines 1-8a Summary

Get out the microscope, because we’re going through this poem line-by-line.

Now, in private, I will reveal
the kind of wood I grew up as from a young offspring.

With these lines, our speaker offers to "reveal" himself, while at the same time surrounding himself in mystery.
By offering to reveal himself "in private," he makes us wonder what he's hiding. Why all the secrecy?
The second line of the poem raises more questions than it answers. Our speaker grew up from a piece of wood? Who, or what, is he?
The Anglo-Saxon word for "offspring," tudor, is mainly used to refer to the offspring of animals or the fruits of plants – in other words, it's not used to describe human children. This word confirms our suspicions that whatever's speaking here isn't human.
This opening connects the poem to the 60 "riddles" that have come before it in the manuscript where it was written, all of which are spoken by inanimate objects. In fact, the riddle right before this poem may, like this opening, be spoken by a piece of wood.

In me men . . . have other land
to establish . . .
salty seas . . .
Very often in a boat I . . . sought
where my lord . . .
over the high seas.

As if the poem weren't tricky enough on it's own, there's another problem: there's only one known manuscript containing this poem, The Exeter Book…and that book has been damaged by a fire. The words here are the only ones editors have been able to make out clearly. The ellipses […] are put in place of words that have been burned or are illegible.
Although the remaining fragments of the poem don't answer our questions about the speaker's identity, they do tell us a little bit about his goals.
Our speaker seems to have traveled a lot in a boat, over the open ocean.
With the verb "sought," we learn that he's traveling in search of someone or something.
With "my lord," the speaker tells us that he's not his own master. In fact, his search, and his travels over the open ocean, may be at the command of this lord.
"Salty seas," and travel in a boat over the high seas, are ideas and images familiar to us from other Old English elegiac (mournful) poems such as "The Wanderer" and "The Seafarer." In those poems, the speakers are in exile, forced to travel against their will. The shared imagery here makes us wonder if our speaker might be in the same boat as them (hehe…pun intended). Maybe he's forced to travel against his will too.