City Trees

Tree of Merit: Flame Tree (Brachychiton acerifolius) Flame tree (Brachychiton acerifolius) is considered one of Australia's favorite native f lowering trees; it is also one of the countr y 's few decid- uous native trees. It's in the same plant family (Malvaceae) as the bot- tle tree (B. rupestris) f rom Western Queensland (the similarit y bet ween these t wo trees lies most obviously in the grey/green bark.) Internationally, this medium to large tree is used in places like California, South Af rica, and the Mediterranean. Where f lame tree is native to dr y and subtropical forests of coastal Australia, it can grow up to 30m ( 98 f t) tall; however, in urban areas it rarely grows taller than 18m ( 59 f t). The canopy is open and sometimes sparse, giving it the appearance of lacking uniformit y. Flame tree is grown in parks, but if the tree is given enough above- and below- ground space and the right growing conditions, it will per form well as a street tree also. It prefers sunny positions, shelter f rom strong winds, and deep, rich, well-drained, moist soil. We haven't obser ved branch drop with this spe- cies of Brachychiton. It is low maintenance in that it rarely requires pruning. Flame tree is mostly popular because of its striking f ier y red bell-shaped f low- ers and large maple-shaped leaves. It is most of ten propagated f rom seed, and f lowering doesn't begin until the tree is at least seven years old, and even then the tree may only f lower ever y three or four years. Flowering occurs in summer af ter the leaves drop and is most prolif ic af ter a period of drought. Aboriginals use f lame tree inner-bark's lace-like f ibers for cords and net- ting, and farmers once used the timber for fencing and shingles. Today, it is most commonly cultivated for decorative and shade-giving qualities. If stressed, f lame tree can be at tacked by borers that cause a clear lumpy substance to fall f rom the seed pods, damaging paint on vehicles parked underneath the tree. This borer can be treated through an insecticide (shor t-term solution) or addressed through bet ter plant health care (long- term solution). The most common cause of fair to poor health of f lame trees in urban areas is heavily compacted and low-nutrient soils. by Sitara Gare, Arboriculture Coordinator, Brisbane City Council, Australia Sitara Gare is an Arboriculture Coordinator for Brisbane City Council, Australia's largest municipal council. Her arboriculture passions lie in educating the public about all the benefits of trees. Flame tree fruit pods dehisce to reveal seeds. Flame tree trunk. Photos on this page courtesy of selectree.calpoly.edu Closeup of the flowers of Brachychiton acerifolius. The maple-like foliage of flame tree. www.urban-forestry.com 39

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