TreeFarm

function harvest()
 turtle.dig()
 turtle.forward()
 while turtle.detectUp() do
  turtle.digUp()
  turtle.up()
 end
while not turtle.detectDown() do
 turtle.down()
end
turtle.back()
turtle.place()
turtle.select(2)
turtle.place()
turtle.place()
turtle.place()
turtle.place()
turtle.place()
turtle.place()
turtle.place()
turtle.place()
turtle.place()
turtle.place()
turtle.select(1)
end

local args = {...}
if args[1] ~= 0 then
 for i = 1, args[1] do
  harvest()
 end
else
 while turtle.getItemCount(1) > 0 and turtle.getFuelLevel() >= 2 do
  harvest()
 end
end