The tunnel house will be used to propagate seeds of native shrubs, trees, wildflowers and grasses.

"We finally got our tunnel house built and this will be opened by Adam at 10am," committee member Kerry Steller said.

"The open is also a good way to celebrate the group's ARC Australia Day award."

The day will feature a continuous barbecue, talks and children's activities.

Peter Metcalfe will give a free talk on plant identification; other guest speakers include Dr Andrew Thornhill (eucalypts), Dr Jane Pickard (walnuts and wattles) and Penelope Sinclair (mixing natives with exotics in your garden).

Ms Steller will conduct a treasure hunt in the woodland for children.

Trees, shrubs and groundcovers will all be for sale at the open day, to be held at the group's Mann Street premises.

The open day starts at 9.30am and is free to all.

The event follows two community plantings undertaken by the tree group for koala habitat at the Kindly Animal Sanctuary on March 13 and March 23.

In a partnership between the tree group and the sanctuary, more than 7000 saplings were planted, aimed at creating a protected habitat for future koala generations.

The planting covers 16.5 hectares of open land at the sanctuary, in Claremont Road, Armidale.

Zoologists, accountants, nurses, teachers, police, council workers, tradies, IT people and children all volunteered their services at the sanctuary over the two days.

Armidale Dominoes Pizza will be also supporting Kindly Sanctuary on April 10 when, between 3pm and 9pm it will hold a "Doughraiser", donating $1 from every pizza sold to Kindly.