Aside from the fact that a forced landing is much more likely to be unsuccessfull at night, other factors which also appear to also have contributed to the very poor night flying accident record are:
1)Spacial disorientation (due to a lack of a visible horizon)
2)CFIT (due to be inablility to see obstacles untill it is too late) and
3)Loss of control due to inadvertantly entering IMC (you cannot see clouds at night)