Steps. 1  1. Perform major pruning during the dormant season. The ideal time to prune a crabapple tree is late winter or in the cold days of early spring, before leaves appear. 2  2. Remove suckers. Suckers are additional branches that begin growing underground and sprout near the base of the tree. 3  3. Remove water sprouts.
The upper crust is 12.5 km thick in crust with an average total thickness of 40 km (ref. 3). If the upper crust is the product of 14% melting, the corresponding residue would be 77 km thick, resulting in a total crustal thickness of 100 km, including the middle crust.
The continental crust consists of various layers, with a bulk composition that is intermediate to felsic. The average density of continental crust is about 2.7 g/cm 3, less dense than the ultramafic material that makes up the mantle, which has a density of around 3.3 g/cm 3. Continental crust is also less dense than oceanic crust, whose density is about 2.9 g/cm 3. At 25 to 70 km, continental crust is considerably thicker than oceanic crust, which has an average thickness of around 7â10 km. About 40% of Earth's surface is currently occupied by continental crust. It makes up about 70% of the volume of Earth's crust.