In "The Split Cherry Tree" by Jesse Stuart, is Pa a good father or a bad father? How?

Pa is a very good father. However, that is not clear at first, so let's trace out how we learn of Pa's goodness. 
The story opens with Dave and some other teenage boys, on a high school field trip, having broken a cherry tree. Dave is very fearful of his father being angry and whipping him for having to stay after school. Dave hurries home. His father is angry and goes to school with him the next day, carrying a gun. Dave is afraid his father will shoot the teacher for keeping him after school to work off his share of the cost of the cherry tree. Dave's father goes on and on about taking Dave out of the school.
At this point, the reader thinks Dave's father is an abusive, coarse, violent man. The father is angry that Dave is being treated differently at the school because he is poor.
However, our idea of Dave's father gradually changes when he gets to the school. He doesn't shoot the professor, and he is open to learning, even spending a day at the school to try to understand it better. By the end of the day, we learn that though poor, older (he is 65) and not well educated, Dave's father is a fine, upstanding man and a good father, a person of compassion and generosity.
We learn three things about Dave's father that show he is a good father. First, he is compassionate toward animals. He says to the professor, who plans to dissect a snake:

I jist don't want to see you kill the black snake. I never kill one. They are good mousers and a lot o' help to us on the farm. I like black snakes. I jist hate to see people kill 'em. I don't allow 'em killed on my place.

Then Dave remembers: 

Pa won't whip a mule at home. He won't whip his cattle.
"Man can defend hisself," says Pa, "but cattle and mules can't. We have the drop on 'em. Ain't nothin' to a man that'll beat a good pullin' mule. He ain't got th' right kind o' a heart!" 

We know that if Dave's father won't be cruel to a snake or farm animal, he's not likely to be cruel to his own child.
 
Dave's father then models generosity and an ability to learn and change. He was angry at Dave's professor and at the high school for taking the students out of the classroom on a field trip, but he takes the time to get to know the professor and the school and decides:

He's a good man. School has changed from my day and time. I'm a dead leaf, Dave. I'm behind.

Dave's father shows compassion and helpfulness toward his son:

If he'll let me I'll get a broom and we'll both sweep one hour. That pays your debt. I'll hep you pay it.

Finally, Dave's father shows what a good father he is by supporting his son and giving him good advice about being an honest and kind person. He wants his son to do better than he has. He doesn't resent his son surpassing him. In every way, he puts his son's needs ahead of his own, which is perhaps the definition of being a good parent:

You must go on to school. I am as strong a man as ever come out'n th' hills fer my years and th' hard work I've done. But I'm behind, Dave. I'm a little man. Your hands will be softer than mine. Your clothes will be better. You'll allus look cleaner than your old Pap. Jist remember, Dave, to pay your debts and be honest. Jist be kind to animals and don't bother th' snakes.