After rereading the Tenrou Island arc I keep finding more and more impressive feats.
In his fight against Erza, Azuma unleashes the full power of Tenrou, which results in a huge explosion which partially burns the roots of the tenrou tree.
The fight started at chapter 236
Tenrou Diameter = 2858.9 meters(From the NF calculation) = 685 px
Tenrou Tree Trunk = 106 px = 106(2858.9/685) = 442.399 meters
Tenrou Tree Trunk = 196 px = 442.399 meters
Burned Roots Diameter = 130 px = 130(442.399/196) = 293.427 meters
This was a sphere, so:
https://www.calculator.net/volume-calculator.html
V = 13228141.825844 m^3
Only about 15% of the space was filled by roots, so:
V = 13228141.825844 * 0.15 = 1984221.2738766 m^3
I’ll use the mct formula to find the energy.
Tree Density = 600 kg/m^3
Mass = V * d = 1984221.2738766 * 600 = 1190532764.32596 kg
Specific Heat Capacity of Wood = 1760 j/kgC
I’ll take the temperature as an average summer day(since it’s a tropical island), a.k.a 23 degrees
Wood burns at 430 degrees , so:
T = 430-23 = 407 degrees celcius = 680.15 K
E = 1190532764.32596 * 1760 * 680.15 = 1425143912995090.98144 joules = 340.61 kilotons(Large Town level)(High 7-C)
Erza tanked this, so this scales to PreSkip Erza's strongest armors