In California, bluegum eucalyptus stands are highly susceptible to fire during the dry season. The bark, which hangs in strips from the stems, readily carries fire into the crowns, and the leaves contain volatile oils that produce a hot fire. Trees are rarely killed by fire, however, as they sprout vigorously from the stems and bases (8). In the moister climate of Hawaii, fire has not been a problem in bluegum eucalyptus stands.
Seedlings are intolerant of frost and temperatures of -5° to -10° C (23° to 14° F) usually kill them. Frost resistance increases with maturity, juvenile foliage being less resistant than mature foliage (4). In 1972 a severe frost in the hills of Berkeley, CA, completely defoliated most of the mature bluegum eucalyptus. The trees were considered dead by several authorities and a salvage logging program was started to remove the fire hazard. A few months later, most of the "dead" trees sprouted from the stems and bases and began to grow again. This sprouting was judged undesirable and several experiments were undertaken aimed at preventing it. The most successful treatment found was to flood axe frills made at the tree bases with a 0.36 kg/1 (3 lb/gal) solution of glyphosphate in water (10). This permanently killed the trees.
The tree is susceptible to drought, particularly on shallow soils. On such soils, subsoiling has been used effectively to permit deeper rooting and to overcome drought susceptibility.
Several insects attack bluegum eucalyptus, although none has been a serious problem in California or Hawaii. One that is common in many parts of the world is the wood borer, Phoracantha semipunctata, which has caused severe damage in South Africa and Western Australia. A scale insect, Eriococcus coriaceus, has caused high mortality in New Zealand. Several defoliating insects in the genera Gonipterus, Chrysophtharta, and Mnesampela, attack the species.
Fungi have generally not been a severe problem with bluegum eucalyptus. Damping off in nurseries caused by Botrytis cinerea has been a problem but is easily controlled. Pythium and Rhizoctonia spp. have also caused damping-off in containers and flats, particularly when old seed was used (16). Fusarium spp. have destroyed quantities of stored seed in Spain. Attack by Diplodia and Armillaria has been reported from several countries, but neither disease is considered serious (8,23).
- Burns, Russell M., and Barbara H. Honkala, technical coordinators. 1990. Silvics of North America: 1. Conifers; 2. Hardwoods. Agriculture Handbook 654 (Supersedes Agriculture Handbook 271,Silvics of Forest Trees of the United States, 1965). U.S. Department of Agriculture, Forest Service, Washington, DC. vol.2, 877 pp. http://www.na.fs.fed.us/spfo/pubs/silvics_manual/table_of_contents.htm
No one has provided updates yet.