Harvesting woods with magnus, colonization and ancestral hall?

[WilsonEvans]

I'm trying to understand the situation: I have magnus, colonization and ancestral hall in the same city. The worker is on a woods tile that gives +70 prod when harvested. I start building a settler, 0/200 prod, I harvest the woods and now the screen says 140/200 prod

That's only 100% increased production, I assume the three are additive and should stack to give me +150% harvest value from woods. What's going on?

 

[KingPiggyXXI]

The extra production from Magnus is included in the chop value. Without Magnus, the chop would've given you less production (about 46, I believe).

 

[Duke William of Normandy]

As @KingPiggyXXI said, the +50% Production Bonus to Chops from Magnus is applied to the Chops' value themselves.