def get_base(point_cloud, base_height):
    """
    Get the base of a point cloud based on a certain height from the bottom.

    Parameters
    ----------
    point_cloud : array
        Three-dimensional point cloud of a single tree to perform the
        wood-leaf separation. This should be a n-dimensional array (m x n)
        containing a set of coordinates (n) over a set of points (m).
    base_height : float
        Height of the base slice to mask.

    Returns
    -------
    mask : array
        Base slice masked as True.

    """
    return point_cloud[:, (2)] <= base_height
