Mae – Your grandma and grandpa lying on a bed suggests they sat up out of sleep and signalled by their smile their support for you.
The fallen tree is indicating either a sense of threat to your identity; this can often suggest a big change in the way you express yourself. It is a breaking down of the influences you lived from in the past, perhaps because your childhood set in place painful or negative influences, or it could suggest the loss or death of a relative or someone close to you. It can also sometimes show the death of someone.
But your dream has specific indicators – the cement pushing the roots up. Cement is often used to hold back the natural forces of growth and to keep a smooth undisturbed surface. This could apply to your past being influenced by forces to keep the status quo. The tree, which indicates your own personal efforts or growth, broke through the forces holding your own growth back. But in doing so it produced a big change in the way you see life and react to it.
I suggest you imagine breaking up the cement to expose the earth – all the influences that contribute to your being. A tree that size must have produced seeds, and so exposing the earth will let new growth occur – a beautiful new tree, no longer held back. See
http://dreamhawk.com/dream-encyclopedia/secrets-power-dreaming/ and
http://dreamhawk.com/dream-dictionary/potential/ Tony