Alrighty friend, let me explain you a math.
We're gonna want to start by setting up a fraction. We'll set up the fraction as height/shadow. The stick's height is 6 feet and the shadow is 2 feet, making the fraction 6/2. The second fraction only gives us the shadow, so the fraction is x/14.
Now, we're gonna do some cross multiplication m8. 6/2 x x/14. Multiply 6x14= 84 and 2x(x)= 2x ---> 2x = 84
Do you some basic algebra here, and divide both sides by 2.
Your final answer is 42, so the tree is 42 feet tall.