Mr Christensen specialises in growing heritage varieties, among them Monty's Surprise, Captain Kidd, Liberty, Molly's Delicious, Gravenstein and Sturmer, which he described as an "old fashioned cooking variety".
"The good thing is with some many varieties is you can enjoy them through different times of the year. For examples the Monty's Surprise is usually ready about mid-April but others we have are ready before Christmas."
He said the trees they gave away should thrive in Wanganui.
"Wanganui's climate is fabulous, We've got one of the most temperate climates in the world. We miss most of the bad weather and our soils are generally excellent as well," he said.
As far as growing the fruit trees is concerned, he said it's just a matter of "putting them in the ground and waiting".
"They all produce abundantly and Monty's Surprise will keep on producing for 100 years. This means you'll have a tree that provides for successive generations."
He said even a tree planted at a rental property will provide for tenants for years.
He said a study of the anti-cancer properties of 250 heritage apple varieties by the research trust found a couple of standouts with exceptionally high levels of antioxidants and Monty's Surprise was one of them.
He discovered an old and large specimen growing on the side of the road in Wanganui and from this tree thousands of Monty's Surprise trees have been propagated and distributed free by the trust to the Wanganui community.
Using overseas research on apples, 250 New Zealand heritage varieties were chemically analysed. That study found the Monty's Surprise apple contained high levels of beneficial compounds, mainly in the skin, which could inhibit cancer cell proliferation.
For more information, visit www.treecropsresearch.org/montys-surprise