function make_bamboo(pos, size)
    for y=0, size-1 do
        local p = {x=pos.x, y=pos.y+y, z=pos.z}
        local node = minetest.get_node(p).name
        if node == "air" then
            minetest.set_node(p, {name="bamboo:bamboo"})
        elseif node == "default:dirt" or name == "default:dirt_with_grass" then
            return
        else
            break
        end
    end
end

minetest.register_on_generated(function(minp, maxp, seed)
    if maxp.y < 2 and minp.y > 0 then
        return
    end

    local c_grass = minetest.get_content_id("default:dirt_with_grass")
    local n_bamboo = minetest.get_perlin(8234, 3, 0.6, 100)

    local vm = minetest.get_voxel_manip()
    local emin, emax = vm:read_from_map(minp, maxp)
    local area = VoxelArea:new{MinEdge=emin, MaxEdge=emax}
    local data = vm:get_data()

    local rand = PseudoRandom(seed % 8000)
    for z = minp.z + 2, maxp.z - 2, 4 do
    for x = minp.x + 2, maxp.x - 2, 4 do
        local bamboo_amount = math.floor(n_bamboo:get2d({x=x, y=z}) * 7 - 3)
        for i = 1, bamboo_amount do
            local p_pos = {
                x = rand:next(x - 2, x + 2),
                y = 0,
                z = rand:next(z - 2, z + 2)
            }

            local found = false
            local node = -1
            for y = 4, 0, -1 do
                p_pos.y = y
                node = data[area:index(p_pos.x, p_pos.y, p_pos.z)]
                if node == c_grass then
                    found = true
                    break
                end
            end

            if found and
                    minetest.find_node_near(p_pos, 5, {"group:water", "default:water_source"}) then
                p_pos.y = p_pos.y + 1
                make_bamboo(p_pos, rand:next(3, 6))
            end
        end
    end
    end
end)