At the beginning of the episode, the narrator says that this fishing ritual is "tri-annual". He goes on to say its every three years. Every three years would be triennial, not tri-annual (three times a year).
Narrator: Ever since there have been fathers and sons... there have been father-and-son traditions. Rituals that bond man to boy. And knit boy to man. In my family, there was one tradition that outranked all others in sheer gross ritual tonnage. The tri-annual Arnold three-day fishing trip. Every few years, Dad would round up the poles and boots and his old Army tent from the attic... and pack us off for a weekend at Berlinger Falls. Not that we had a choice in the matter. So, that fall of nineteen-seventy-two... we headed off for our first expedition since I was twelve. The funny thing is... of all the trips we ever made... it's the one I remember most. Not because it was the best - or the worst... but because... it was the last.
Narrator: Berlinger Falls. Fresh air, trees... a suburban outdoorsman's Valhalla. Where men could kick back in the company of men - such as they were. It was a place where dads could be dads. And kids could be kids. Where fathers and sons could share things. Together. Three men in a tent.
Narrator: We'd come this far. No sense turning back, now. We fished the rest of that day. We didn't catch much. Dad said he'd like to move up here, and open a bait shop. I told him it was a great idea. I think he believed it. And in the end... I guess we finally figured out why we'd come here in the first place. We'd come... to say goodbye.
Narrator: The hardest part of growing up is having the ones you've always turned to, turn to you.
"Going Up the Country" by Canned Heat
"Fishing Blues" by Taj Mahal