The World Collection has a diverse range of genera. Many beautiful exotic favourites are represented alongside rare and unusual trees. In particular, there are up to forty different clades of oak growing in the Park (Genus Quercus).

When the Tree Park was established in 1980, there were already many well grown, attractive specimen trees that formed the foundation to the Tree Park project, dating back to 1901 when two Wych Elms (Ulmus glabra) were planted at the garden gate of the then Yungerup homestead.

Soon after 1901 the first English Oak (Quercus robur) was established at Yungerup. These plantings were followed by the Persimmons in 1904. Other significant historical plantings include a spreading Irish Strawberry Tree (Arbutus unedo) and a massive English Mulberry (Morus nigra).

The old pear trees at Pear Tree Look-out are Josephine variety and are the last remnants of the original commercial plantings at Yungerup that covered the hillside in circa 1909.

In 1930 the first Liquidambar (Liquidambar styraciflua), the Norway Maple (Acer platanoides) and the first Golden Poplars (Populus serotina ‘aurea’) were established on Yungerup.

The avenue of Golden Poplars and Deodar Cedars (Cedrus deodara) were planted in 1937 and is now called “Olwen’s Avenue”. The Josephine Pears were planted at the look-out in 1940 and the “Cleveland Oaks” were planted in 1946 by Olwen at the site where her parents camped when they first arrived at the property.

The remnant apple orchard, near Yungerup Spring, was planted in 1960.

In 1908, the first ornamental farm plantings at Golden Valley occuried with the planting of the avenue of London Planes (Plantanus acerifolia) on the hill behind the Homestead. Other planting followed including two English Oaks.

The botanical collection in total is of significance at local, regional, State and national levels and since the decision by the Board of Kings Tree Park in Perth to focus on increasing its natural bush, Golden Valley has become the most diverse botanic collection of trees in Western Australia.

Within the World Collection, there is a section containing pine trees (Pinus radiata) which have been partially harvested twice, most recently in 2019. Unlike in most plantations, the Tree Park retained many of these semi-mature pines to grow to full maturity while establishing two hectares of different provenances of  Pinus canariensis as a trial planting. This pine species has potential to become, alongside the well-known Pinus radiata, a preferred softwood plantation choice. P. canariensis is among the most drought hardy of the pines, and light fuel reduction burns can be carried out underneath them because they have thick barks. They are slower growing but produces stronger, denser timber.