He was a retired chartered accountant who kept detailed records for the charities unit in the Department of Internal Affairs, banked money, provided refunds and handled investments.
"The rest of us were concerned about arranging and leading trips. It freed us up completely to do that. Our collective wisdom doesn't cover those roles," Scoullar said.
The job would suit a retired accountant, Scoullar said.
Trustees already have an outline for next year's programme, and they have money in the bank.
The trustees are Scoullar and Alan Donald, and they are seeking others.
The trips and events of the programme are organised by groups - Forest & Bird, the Conservation Department, Wanganui Tramping Club, Friends of the Whanganui River, Pātea Historical Society and the Whanganui Regional Museum.
Some trips are especially popular. They include those to Whangamomona and into the Waitōtara Valley, the trip to the Springvale Bridge over the upper Rangitīkei River and the tours of Rangitīkei heritage houses.
The summer programme's 30-year history has embedded it in public life and its "fan base" would be disappointed if it went into recess, Scoullar said.
The programme was started by Conservation Department ranger Ridgway Lythgoe, who brought the idea from his previous work in Tongariro National Park.
When the Conservation Department pulled out, Whanganui woman Wendy Pettigrew started the trust to keep the programme going.
In 2015 there was a crisis when Pettigrew died, Scoullar said, because she was a "lead from the front" person and kept much of the knowledge in her head.
"It took us a while to find our own feet and work out our own identity. We survived the Wendy Pettigrew crisis, so we can survive again."
• Anyone who can help is asked to contact David Scoullar dkmscoullar@gmail.com, or 343 2836.
