If it is taxable income it must be reported on the tax year that the distribution was made, not when you cash the check. As soon at the check was written you had constructive receipt of the money - it does not matter when, if ever, you actually cash the check. The trustee will probably issue a K-1 form that you report and the IRS received a copy of.
**Disclaimer: This post is for discussion purposes only and is NOT tax advice. The author takes no responsibility for the accuracy of any information in this post.**