Associate professor Cristopher Brack "served" a smorgasbord of ideas for a meal to a sold-out audience and others watching on Zoom. Brack says he has "performed" every year, speaking on tree-related topics and this year's theme came from a dare following one of his first seminars entitled Trees do impossible things (the physical feats of trees) where he floated the idea that all problems could be solved by trees.

The meal started with the pyramid of needs, of which physiological - our need for air, water, food, warmth and rest - are the most basic. Trees provided food pre-humans, they were responsible for survival in this land and have served as a back-up larder.

Sam van Aken, a professor at Syracuse University and artist, grafted 40 different varieties of stone fruits onto one tree. Brack said the Food and Agriculture Organisation of the United Nations estimates there are 2.2 million fruit tree orchards across the world and 37 million fruit trees.

In a Canberra winter, Brack suggest his sweet and nutritious starter of oranges, lots of vitamin C to fight winter colds and something bright and fresh. A base of navel and blood oranges, maybe olives and feta/goat/ cheese with almond, pine and cashew nuts - noting that nuts are fruits too.

Young tender leaf salad = beech, birch, Chinese elm, fennel, mulberry, hawthorn, sassafras and linden leaves. He says we may need to adapt our taste to more bitter leaves.

In China, leaves from the fragrant spring tree, Toona sinensis (Cedrela sinensis) the Chinese cedar or mahogany, are a common stir fry ingredient with eggs. In the United States the tree is known as "the beef and onion plant".

A forest of Toona sinensis has been planted at the National Arboretum, Canberra. Visitors may not taste the leaves but their copper brown new leaves in springtime can be admired.

A specimen was growing in the suburb of this writer but the owner of the tree, a neat freak, cut it down as the species suckers.

As Brack says, we are all familiar with bark in the form of cinnamon quills, a warming spice from the inner layer of bark which is carefully peeled from the species Cinnamomum.

More unusual, in Nordic countries, birch bark flatbread is baked using a flour made from silver birch trees. In earlier times the bread was an indication of wealth as it meant you had access to a birch forest. It has no gluten.

For our photo, Brack's wife, Jacqueline Brack, captured an image of him in the silver birch forest at the National Arboretum last week.

A video, How to make birch bark flour cookies, on YouTube comes from Tree Time Canada, an Edmonton tree nursery. In the kitchen with Leeanne is brief but funny. Words are printed on the screen. Watch out for the glass of wine and the cook's red fingernails.

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For seeds, Brack says nothing is better than our wattle trees, seeds from which were used by Indigenous people, among the oldest baking civilisations in the world. Wattle seeds are now popular with Australian chefs and home cooks.

Brack says wood is no good as a food because as we can't digest cellulose. However, from the jungles of Argentina comes Jacaratia spinosa, which stores water in the trunk like our bottle trees.

Jacaratia wood is low in cellulose and can be eaten raw, soaked in honey or maple syrup or ground and added to jams. You could serve cheese on a wooden board and then eat the board.

In current times, Argentinian celebrity chefs have made wood-based desserts as award-winning dishes.

Noodles made from paper pulp which are rich in fibre and low in calories and carbohydrates, free of gluten and fat. The noodles originated via a clothing factory in Japan, Omikenshi Co. which makes rayon from wood pulp.

Bitter beer was made from bark in the Middle Ages. Now new beverages are made from wood. Four kilos of cedar produces three to eight litres for drinking, alcohol content is 15 per cent, similar to Japanese sake. Brack says foresters of Japan are given two hours a week to experiment and dream-inspired research is valued.

Pulp from wood and shellfish, a replacement for plastic, is water-resistant. It can be used to wrap food then you can eat the bag, sold in vending machines in Japan. It keeps food fresher and is compostable.