In this case I'm talking about the bias>magnitude. Alpha and gamma are like a twist in the direction of the spline through the CP. Magnitude is like a stiffness of the spline as it goes through the CP
Here are three copies of a spline that is bent like your tree. The magnitude of the CPs on the top have the default 100%. The second one has a higher magnitude, it looks lumpy, like your tree. The third one has a low magnitude, it has sharper corners.
Magnitude has separate In and Out values. You don't know which side is In or Out until you try.
You can change a bias directly with the bias handle or by numbers in the Properites.
You can change several selected CPs at once with either method.