ComputerCraft - Jungletree Cutter

-- place turtle on the left side of front of the 2x2 tree
-- place some coal in slot 1

function testfuel()

    if turtle.getFuelLevel() < 5 then

        turtle.refuel(1)

    end

end
print("How tall is the tree? ")
height = read()

testfuel()

turtle.dig()
turtle.forward()

for i = height, 1, -1 do

    testfuel()

    for j = 4, 1, -1 do

        turtle.dig()
        turtle.forward()
        turtle.turnRight()

    end

    turtle.digUp()
    turtle.up()

end

for i = height, 1, -1 do

    turtle.down()

end