turtle.select(1)
turtle.refuel();
turtle.select(2);

function mineTree()
    turtle.dig();
    turtle.forward();
    x = true;
    while x do
        turtle.digUp()
        turtle.up();
        if (turtle.compare() == false) then
            x = false;
        end
    end

    b = true;
    while b do
        b = turtle.down();
    end
end

b = true;
while b do
    b = turtle.forward();

    if (turtle.compare()) then
        mineTree();
    else if turtle.detect() then
        turtle.dig();
    end

end
end