There is a 50% chance of getting Huntingdon's disease.
Explanation:
Assume the affected parent is Hh, where H is the Huntingdon's disease allele and h is the unaffected allele. One parent is unaffected, or hh. You have a 50% chance of getting the H allele from the affected parent.
If I had the choice to get tested, for Huntingdon's disease, I would do it. I would want to know so that I wouldn't live my life worrying about it everyday.
The fallen tree would have let in more sunlight as it was blocking sunlight from getting in most of the time. Since the tree fell more sunlight will be able to get in. The only problem would the fact that there will be less space depending on the size of the tree and how it fell over.