Main Branch August Meeting Report.
We welcomed back to the Club, Robert Powell, who is well-known to many of us and who’s back in Perth for a few weeks, having been living in England since 2010. Robert is known for his excellent books Leaf and Branch and Growing Locals. He has a website Tree Pictures of photos he has taken, together with historical photos, and information about them.
Robert’s passion is the trees of Perth and the South West. He has a keen eye for their beauty, what makes them interesting, and evidence for the life-history of individual trees. He is also keen on discovering the ecological role of the various local tree species, as well as the effect that a tree’s immediate environment has on that tree. This passion was ignited when, as a child in Floreat, two mature Tuarts in his back yard produced seedlings, which he helped to transplant to his aunt’s place.
First, Robert talked about the form of trees, such as whether they had a main shaft typical of forest trees such as the Karri, or a splitting structure like a Swamp Yate. Then there is the tree’s expression, such as whether it has been affected by salt winds or soil infertility or whether fire or insects or surrounding vegetation have modified its growth. That is not to say that these adverse circumstances spoil the appearance of the tree. Far from it—they can enhance its appearance and give it character. Repeated patterns in a tree give it aesthetic unity, and the details of its structure, colour and texture give it interest. In trees with lush, dense foliage the structure is hidden, but in those with sparse foliage, the structure is on display.
Each species has its individual character. Jarrah can grow to a magnificent size with a shaft-like trunk, as Robert showed in a 1926 photo, but on the sandy coastal plain it has a more splitting structure. Marri is renowned for its flowers, which grow densely on the outside of the tree in late summer. The fruits, or “honkey nuts”, appear a year later, and are so heavy that they can weigh the growing branch down, resulting in droopy or wiggly branches. Different bird species make different marks on honkey nuts when they dig out the seed.
The Tuart has a graceful form, as shown in a photo of a massive tree taken in 1896 in the Ludlow Forest near Busselton. Tuarts were once called White Gums—hence the suburb of White Gum Valley. The Flooded Gum has rough bark low on the trunk and smooth (deciduous) bark higher up. It was once called the Blue Gum—hence Blue Gum Lake in Mt Pleasant. Sometimes it shows explosive regeneration along the edge of lakes or waterways. The Buttergum, which grows on the scarp, has butter-coloured bark when it is newly exposed, and the Powderbark’s new bark is an apricot colour. Modong, the biggest paperbark, has real character with its twisted branches and clumps of dense foliage. The Swamp Banksia, on a windy day, shows pulses of white, given by the pale underside of the leaf. The world’s only tree-sized mistletoe, the WA Christmas Tree, has a beautiful form, quite apart from its striking floral display.
Some eucalypts grow as many-stemmed mallees, able to re-sprout after a fire from a lignotuber, which can be many metres across and thousands of years old. Most mallees grow in semi-arid areas, but a local example is the Fremantle Mallee, which grows on thin soils over coastal limestone. Some species (e.g. Yate) can grow as trees or mallees, depending on conditions.
Looking closely at a tree, there are signs of insect activity such as galls, blisters and deformed leaves. Usually trees can accommodate this damage, and we can learn to see it as interesting ecologically and aesthetically rather than as a blemished tree. Much of the character of trees results from the work of insects. Old trees often provide more habitat for wildlife, with their hollow limbs, cavities and peeling bark.
Robert suggests putting our appreciation of trees into practice by providing spaces and enclosures that allow for natural regeneration, with uneven spacing. Branches of Freshwater Paperbarks placed in the water at Herdsman Lake in the spring of 1982 resulted in extensive regeneration of seedlings along the shoreline.
After Robert’s talk I think we will all look at trees in a new light, from both an aesthetic and an ecological perspective. His books and website are well worth looking at.
Mike Gregson