“WHAT’S that tree?”

I must have asked the question at least 50 times as I enjoyed an afternoon visit with my husband to The Yorkshire Arboretum.

Known as ‘the arb’, it is a vast, undulating garden filled with trees and shrubs from across the globe.

The impressive collection has been sourced from temperate regions around the world, including Chile and Australasia as well as North America, Europe and Asia. The result is a spectacular display of rare trees alongside native plants and wildlife for visitors to enjoy as a place of inspiration, education and conservation.

Native oak, ash and beech share the 120-acre space with the likes of Japanese maple, Turkish alder, Australian eucalyptus and American fir.

What makes it interesting is that each is tagged with the name and country of origin. I think the date of planting is included, but some tags bear two dates, which we found a bit confusing.

There’s also a series of information posts linked to tree trails with detailed notes about particular trees. The lovely spreading eucalyptus - unlike any of the long, straggly specimens I had seen previously - was an endangered variety restricted to a few sites in the mountains of the Australian state of Victoria.

It was, no doubt to the delight of those managing the site, thriving on it south-facing, exposed sand bank, and producing fertile seeds.

Also doing well, the hardy Turkish alder, used to growing in mountainous terrain, had taken to the Yorkshire soil.

Lying within the Castle Howard Estate, the arboretum as we know it today was created through the enthusiasm and partnership of George Howard - Lord Howard of Henderskelfe - and garden designer James Russell.

George Howard had begun an arboretum here in 1959, but rabbits killed most of the trees, and it was not until after James Russell had moved to Castle Howard in 1968 and created the woodland garden in Ray Wood that they turned their attention to re-founding the arboretum.

John Simmons, then curator of the Royal Botanic Gardens at Kew, instigated the formation of the Castle Howard Arboretum Trust as a partnership between Kew and the Castle Howard Estate. Established in 1996, the trust preserves and develops the collections in both the arboretum and Ray Wood in Castle Howard grounds.

Tree trail maps are free at the arb’s visitor centre, where we enjoyed tea and fluffy home-made scones on the sunny terrace. The cafe sells light snacks and also offers afternoon tea. We were also given leaflets about future events by a helpful member of staff.

The last time I visited the attraction, a few years ago, there were fewer paths across the site, now the garden is criss-crossed by tracks through woodland and wildflower meadows. It has also matured, with more clearly defined areas.

I liked the pine forest, with towering trees, giant cones and the rich smell of pine. My husband was drawn to the Atlas cedar, recognizing its shape from the Atlas mountains in Algeria where his family lived for a while.

It was perfect weather when we visited - sunny and blustery. It was lovely to hear the sound of wind rustling through the trees.

As we roamed we met a group of Chinese tourists, some getting around on motorised all-terrain mobility buggies which, subject to suitable weather and ground conditions, are on free loan to visitors with disabilities.

Along Furniture Makers’ Walk, trees traditionally used by craftsmen include oak, beech, silver birch and ash.

There’s a view of the lake from this side of the arboretum. A lakeside walk was unfortunately out of bounds when we visited, while restoration work is carried out. A sign indicated that it would be reopening this summer, and it is hoped work will be finished this week.

For families with children there is plenty of space to run around and build dens. Young visitors can collect a sticky strip of card from the visitor centre, on which to place finds such as leave, grasses and feathers. Parents are encouraged to upload them onto Instagram or Facebook, or email them to show staff. They can also pick up a tick list of insects to spot.

Throughout the summer ‘discovery days’ for families include hour-long sessions such as pond dipping and a look at minibeasts.

There’s a Lottery-funded photography project to take part in, by capturing scenes at eight viewpoints around the site.

A small play area for very young children has obstacles carved from wood. Nearby, a birdwatching hide would have benefitted from a few feeders outside to entice feathered visitors.

The Yorkshire Arboretum has received initial support from the Heritage Lottery Fund for a project ‘If Trees Could Talk’ which aims to tell the story of the arboretum’s trees, its history and rich natural biodiversity to a wide audience.

As part of this project a series of events are taking place, including sessions on landscape photography, pruning and listening to trees.

*Yorkshire Arboretum is open from February 1 to November 30. At weekends until October 31 there is late entry and café opening until 4.30pm.

*The Yorkshire Arboretum, Castle Howard, York YO60 7BY T: 01653 648598. For prices visit yorkshirearboretum.org.