tree.lua

g = 0
while g < 100 do
    if turtle.getFuelLevel() < 5 then
        turtle.refuel()
    end
    if turtle.detect() then
        turtle.dig()
        turtle.forward()
    elseif turtle.detectUp() then
        turtle.digUp()
        turtle.up()
    else
        turtle.down()
    end
    g = g - 1
end