To start us off, I drew a picture of the scenario (see image attachment). A drawing is very helpful to visualize how things are set up and often help point in the direction of properly solving. That is true for me anyway. Notice how I only focus on the simple geometry and I do NOT include any other extra visual information (about trees or anything like that). The only thing we care about is the angle x which is unknown for now
x = angle of elevation
Essentially we have a triangle sitting up top a rectangle. The triangle is the more important figure to focus on. The horizontal leg of the triangle is 30 ft. This is the adjacent side because it's the leg closest to angle x. The opposite side is 12 ft because 22-10 = 12. Hopefully the drawing conveys this if it's a bit confusing how I got 12.
Now onto the trig portion. We use tangent because we have two known sides of opposite and adjacent
tan(angle) = opposite/adjacent
tan(x) = 12/30
tan(x) = 0.4
Now use arctangent to isolate x. Be sure to be in degree mode (not radian mode)
tan(x) = 0.4
arctan(tan(x)) = arctan(0.4)
x = 21.8014094863519
x = 22
So the angle of elevation is roughly 22 degrees