OK...I will take a shot at this one.
If the first line is "From the frozen brook I withdrew my hand," then I have no idea what the "answer" is for that one. Part of the reason for that is that if the brook is frozen and you hand is in it then your hand is frozen as well and you won't be able to withdraw your hand...just saying...
For the second line "And I understand" I believe the answer is:
Know -- As in "understand"
For the third line "As yesterday I understood." I believe the answer is:
Knew -- As in "understood"
For the fourth line "My sweat runs free while cutting wood." I believe the answer is:
Hew -- As in cutting wood
For the fifth line "Like yesterday's limbs and I feel I should" I believe the answer is:
Hewn (I hope that is an actual word!!) -- As in having cut wood
For the sixth line "Have the need for planting grass" I believe the answer is:
Sow (That is the planting of seeds version of the word!) -- As in planting seeds
For the seventh line "As I have done many times in the past." I believe the answer is:
Sown (And again I do hope that is a real word!! :) ) -- As in having planted seeds