The board treasurer is the officer responsible for the financial wellbeing of the organization. In smaller organizations, it’s not uncommon for the treasurer to manage the nonprofit’s day to day banking, records of receipts, and disbursements. Since all board roles change as the organization gets larger, the treasurer of an older and larger nonprofit may take a high level role such as approving large expenses or leading the committee that creates the nonprofit’s budget. While the treasurer is not required to be an accountant, this person should have experience in keeping track of financials and be the organization’s point of accountability—even if the bookkeeping is outsourced. This person is usually one of the signatories for the nonprofit’s bank accounts when the organization is small or just starting out.

Other duties may include:

• Enforcing financial policies and procedures
• Overseeing the organization’s cash flow 
• Advise the board on fiscally responsible strategies/investments 

Articles:
https://www.boardeffect.com/blog/duties-nonprofit-treasurer/