Yea, as I edited when I remembered, the strong trade-off on land area is biomass fuels like corn alcohol. If you can grow that you can certainly grow animal fee

Yea, as I edited when I remembered, the strong trade-off on land area is biomass fuels like corn alcohol. If you can grow that you can certainly grow animal feed. Some tree-farming is indeed on steep ground, but I couldn't guess what proportion actually. (Big old trees are more likely to be on steep ground, as the ones in the valleys were cut long long ago, but those are much more valuable.)