redwood farm with gps for crashing servers

local xcord=
local ycord=
local zcord=

local function checkFuel()
        if turtle.getFuelLevel() < 100 then
                turtle.select(1)
                turtle.refuel(1)
        end
end

function locate()
    g = vector.new(gps.locate(5))
    turtle.digUp()
    turtle.up()
    turtle.dig()
    turtle.forward()
    g2 = vector.new(gps.locate(5))
    turtle.back()
    turtle.down()
    if g.x == g2.x then
        if g.y > g2.y then
            turtle.turnLeft()
            turtle.turnLeft()
        else
        end
    else
        if g.x > g2.x then
            turtle.turnLeft()
        else
            turtle.turnRight()
        end
    end
end

function calc()
    xmove = xcord - g.x
    if xmove < 0 then xmove=xmove*(-1) end
    ymove = ycord - g.y
    if ymove < 0 then ymove=ymove*(-1) end
    zmove = zcord - g.z
    if zmove < 0 then zmove=zmove*(-1) end
end

function digForward()
    turtle.dig()
    turtle.forward()
    checkFuel()
end

function move()
    if xcord ~= g.x then
        if xcord < g.x then
            turtle.turnRight()
            for i=1,xmove do
                digForward()
            end
            turtle.turnLeft()
        else
            turtle.turnLeft()
            for i=1,xmove do
                digForward()
            end
            turtle.turnRight()
        end
    end
    if ycord ~= g.y then
        if ycord > g.y then
            for i=1,ymove do
                digForward()
            end
        else
            turtle.turnLeft()
            turtle.turnLeft()
            for i=1,ymove do
                digForward()
            end
            turtle.turnLeft()
            turtle.turnLeft()
        end
    end
    if zcord ~= g.z then
        if zcord < g.z then
            for i=1,zmove do
                checkFuel()
                turtle.digDown()
                turtle.down()
            end
        else
            for i=1,zmove do
                checkFuel()
                turtle.digUp()
                turtle.up()
            end
        end
    end
end

local function startup()
        print("coal in slot 1")
        print("saplings in slot 2")
        print()
        print("starting in 5")
        sleep(5)
end

local function column()
        local height = 0
        while turtle.digUp() do
                turtle.dig()
                checkFuel()
                turtle.up()
                height = height + 1
        end
        turtle.dig()
        checkFuel()
        return height
end

local function columnDown(height)
        for i=1,height do
                checkFuel()
                turtle.dig()
                turtle.digDown()
                turtle.down()
        end
        turtle.dig()
end

local function digmove()
        checkFuel()
        turtle.dig()
        turtle.forward()
end

local function fell()
        digmove()
        local height = column()
        turtle.turnRight()
        digmove()
        turtle.turnLeft()
        columnDown(height)
end

local function fellcrash()
        digmove()
        local height = column()
        turtle.turnLeft()
        digmove()
        turtle.turnRight()
        columnDown(height)
end

local function replant()
        turtle.select(2)
        turtle.place()
        turtle.turnLeft()
        turtle.forward()
        turtle.turnRight()
        turtle.place()
        turtle.turnRight()
        turtle.place()
        turtle.turnRight()
        turtle.forward()
        turtle.forward()
        for slot=3,9 do
                turtle.select(slot)
                turtle.drop()
        end
        turtle.turnLeft()
        turtle.turnLeft()
        turtle.forward()
        turtle.select(2)
        turtle.place()
        while turtle.compare()==true do
                sleep(30)
                turtle.select(2)
        end
end

function needCoal()
        return turtle.getItemCount(1) < 10
end

function needSap()
        return turtle.getItemCount(2) < 10
end

function getSap()
        turtle.select(2)
        turtle.suckDown()
        turtle.select(3)
        turtle.dropDown()
        while turtle.getItemCount(2) < 60 do
                turtle.suckDown()
                                turtle.select(3)
                                turtle.dropDown()
                                turtle.select(2)
        end
end

function getCoal()
        turtle.select(1)
        turtle.turnLeft()
        turtle.suck()
        turtle.select(3)
        turtle.drop()
        while turtle.getItemCount(1) < 60 do
                turtle.suck()
                                turtle.select(3)
                                turtle.drop()
                                turtle.select(1)
        end
        turtle.turnRight()
end

startup()
locate()
calc()
move()
turtle.turnRight()
turtle.forward()
turtle.turnLeft()
fellcrash()
turtle.back()
while true do
    if needSap() then
        getSap()
    end
    if needCoal() then
        getCoal()
    end
    fell()
    replant()
end