Eucalyptus is one of the most recognizable--and perhaps the most hated--genuses of tree in California. No other tree has elicited such strong emotions and widespread campaigns to remove them from the landscape. There are approximately 1,000 species of Eucalyptus worldwide, with the majority native to Australia where they are perhaps the most important and abundant trees. They belong to the family Myrtaceae along with many other Australian plants.
Some Eucalyptus trees have undeniably caused problems in California, and were overplanted during past decades. For a time after their introduction from Australia, they were seen as a miracle tree that would solve looming wood shortages, dry up disease-ridden swamps, and grow rapidly without much care. As a result, thousands of acres of Eucalyptus were planted across the state, forming dense, shaded forests that exclude most other plant species. The resulting forests were extremely flammable, and after several destructive fires, land managers began removing them from some landscapes. In urban areas, some species have a reputation for dropping large branches or toppling in winter storms.
All that said, Eucalyptus are an important part of the California landscape and have many positive attributes as well. There probably isn't another tree that grows as large and as rapidly in such dry conditions. In Sacramento, I'm almost certain that the largest broad-leaved trees are Eucalyptus, and it's not particularly close. It's hard not to admire a 100' tree with an 8' diameter trunk that can survive on rainfall alone. In the highly developed regions of coastal California where virtually all mature native trees were removed, Eucalyptus are often the only sizable trees left, and many wildlife species have come to depend on them for habitat. In light of this fact, some land managers no longer seek to eradicate Eucalyptus, and instead thin them, leaving the largest and most valuable trees as habitat, while creating space for native trees and reducing fire risk. Finally, it's worth stating that not all species in such a diverse genus are the same. Dozens of species have been introduced to California, and most have not caused problems here.
As far as our local Eucalyptus species, there are too many to name them all, though I hope to document them eventually on their own pages. By far the most common species in our local area is E. camaldulensis, the red river gum. It tolerates both drought and flooding and has naturalized to a notable extent in our local waterways. Other local species include E. sideroxylon, E. globulus, E. cinera, E. polyanthemos, E. leucoxylon and E. viminalis, among others.
Eucalyptus is a beautiful and diverse genus, but one that should be planted thoughtfully. We do not want to repeat the mistakes of the past by planting the wrong species in the wrong places. But I suspect Eucalyptus will continue to play a role in our urban forest, if we learn which species are best for which situation. Its hard to imagine a genus that is better situated to fulfill our need for tough, adaptable trees that are ready to face climate change head on.
Some Eucalyptus trees have undeniably caused problems in California, and were overplanted during past decades. For a time after their introduction from Australia, they were seen as a miracle tree that would solve looming wood shortages, dry up disease-ridden swamps, and grow rapidly without much care. As a result, thousands of acres of Eucalyptus were planted across the state, forming dense, shaded forests that exclude most other plant species. The resulting forests were extremely flammable, and after several destructive fires, land managers began removing them from some landscapes. In urban areas, some species have a reputation for dropping large branches or toppling in winter storms.
All that said, Eucalyptus are an important part of the California landscape and have many positive attributes as well. There probably isn't another tree that grows as large and as rapidly in such dry conditions. In Sacramento, I'm almost certain that the largest broad-leaved trees are Eucalyptus, and it's not particularly close. It's hard not to admire a 100' tree with an 8' diameter trunk that can survive on rainfall alone. In the highly developed regions of coastal California where virtually all mature native trees were removed, Eucalyptus are often the only sizable trees left, and many wildlife species have come to depend on them for habitat. In light of this fact, some land managers no longer seek to eradicate Eucalyptus, and instead thin them, leaving the largest and most valuable trees as habitat, while creating space for native trees and reducing fire risk. Finally, it's worth stating that not all species in such a diverse genus are the same. Dozens of species have been introduced to California, and most have not caused problems here.
As far as our local Eucalyptus species, there are too many to name them all, though I hope to document them eventually on their own pages. By far the most common species in our local area is E. camaldulensis, the red river gum. It tolerates both drought and flooding and has naturalized to a notable extent in our local waterways. Other local species include E. sideroxylon, E. globulus, E. cinera, E. polyanthemos, E. leucoxylon and E. viminalis, among others.
Eucalyptus is a beautiful and diverse genus, but one that should be planted thoughtfully. We do not want to repeat the mistakes of the past by planting the wrong species in the wrong places. But I suspect Eucalyptus will continue to play a role in our urban forest, if we learn which species are best for which situation. Its hard to imagine a genus that is better situated to fulfill our need for tough, adaptable trees that are ready to face climate change head on.