treeFarm 1.2.1

local t = turtle

local function forward(x)
    for i = 1, x do
        t.forward()
    end
end

local function rTurn(x)
    for i = 1, x do
        t.turnRight()
    end
end

local function lTurn(x)
    for i = 1, x do
        t.turnLeft()
    end
end

local function up(x)
    for i = 1, x do
        t.up()
    end
end

local function down(x)
    for i = 1, x do
        t.down()
    end
end

local function back(x)
    for i = 1, x do
        t.back()
    end
end

local fuelAmount = t.getFuelLevel()

local function fuelCheck()
    if fuelAmount < 5000 then
        back(3)
        os.sleep(5)
        rs.setOutput("left", true)
        os.sleep(5)
        rs.setOutput("left", false)
        t.select(3)
        t.refuel(all)
        forward(3)
        print("Gassed up and good to go!")
    else
        print("Still Rollin!")
    end
end

local itemCheck1 = t.getItemCount(1)
local itemCheck2 = t.getItemCount(2)

local function bonemealCheck()
    t.select(2)
    if itemCheck2 < 20 then
        back(3)
        rs.setOutput("back", true)
        os.sleep(15)
        rs.setOutput("back", false)
        forward(3)
    else
        print("Ready to Bone")
    end
end

local function saplingCheck()
    t.select(1)
    if itemCheck1 < 5 then
        back(3)
        rs.setOutput("right", true)
        os.sleep(5)
        rs.setOutput("right", false)
        forward(3)
    else
        print("It's time to Lay")
    end
end

local function grow()
    t.select(2)
    while t.place() do
        t.place()
    end
end


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

local function harvest()
    t.dig()
    for i = 1, 15, 1 do
        t.digUp()
        up(1)
    end
    down(15)
    back(1)
end

while true do
    saplingCheck()
    bonemealCheck()
    fuelCheck()
    plant()
    grow()
    harvest()
end