local function log()
    turtle.dig()
    turtle.forward()

    turtle.digUp()
    turtle.up()
    turtle.digUp()
    turtle.up()
    turtle.digUp()
    turtle.up()
    turtle.digUp()
    turtle.up()
    turtle.digUp()
    turtle.up()
    turtle.digUp()

    turtle.down()
    turtle.down()
    turtle.down()
    turtle.down()
    turtle.down()
    turtle.back()
end

local function plant()
    turtle.select(1)
    turtle.place()
end

while true do
 turtle.select(1)
 while turtle.compare() do
  os.sleep(5)
 end
 if turtle.getFuelLevel() < 500 then       --fuel check
    turtle.select(2)
    turtle.refuel();
 end
 log()
 plant()
end