To me, the conflict in this poem is an external conflict. It is a conflict between man and nature. At times, I think that the orchard also represents man rather than nature. This is because the orchard is a thing that is made by people.
So, in this poem, the speaker and the orchard are struggling against the forces of nature. They have to contend with animals and they have to contend with the temperature and things like that.
So the major conflict is whether the speaker and his orchard can defeat the forces of nature.