Dr Amy Jane Beer explores the marvels of all things arboreal – from the world's loneliest tree that also helped define our current geological era to the 400 year-old apple tree that inspired Newton's theory of gravity. Plus she takes a look at trees' wellbeing benefits too.

Curator Matt Pottage investigates the concept of Champion Trees, highlighting some of the magnificent specimens to be found at RHS Garden Wisley. And did you know that some conifers are deciduous and offer fabulous autumn colour? Matt is a conifer fanatic and shares some suggestions to light up your autumn garden.

And finally… there's a call for citizen scientists as we're on the hunt for a new tree pest with RHS scientist Jassy Draculik. Her 'Check a sweet chestnut' campaign seeks to track the spread of a recent arrival to Britain, the Oriental chestnut gall wasp. Tune in to find out how you can help protect our precious chestnut trees.

Selected plants mentioned:

• Cercidiphyllum japonicum (katsura or candyfloss tree)
• Liquidambar styraciflua 'Wisley King'
• Pinus coulteri (Coulter pine)
• Pseudolarix amabilis

Useful links

• More information on choosing and planting trees
• Check a sweet chestnut
• Visit RHS Garden Wisley
• Join the RHS for free visits to Wisley and to get your monthly copy of The Garden magazine