CFrame math does not equate to tree rotation?

So im trying to create an animated tree script for my trees yet my script is unable to account for the current rotation of the tree.

I would like to animate here: http://prntscr.com/nqp0zn

Yet it changes it to here: http://prntscr.com/nqp17f

Here is my code that I am using.

local treepos = script.Parent.Position
treepos = Vector3.new(treepos.x, treepos.y-0.2, treepos.z)
local x = 0
local z = 0
local T = -99999
local tall = script.Parent.Size.Y / 2
local rand = (math.random(0,20))/10
while true do
    x = treepos.x + (math.sin(T + (treepos.x/5)) * math.sin(T/9))/3
    z = treepos.z + (math.sin(T + (treepos.z/6)) * math.sin(T/12))/4
    script.Parent.CFrame = CFrame.new(x, treepos.y, z) * CFrame.Angles((z-treepos.z)/tall, 0,(x-treepos.x)/-tall)
    wait()
    T = T + 0.12
end

Any help is greatly appreciated!