Californian-Australian Exchange

With a little help from our friends, we have discovered a new resource to help us understand why Blue Gum eucalyptus was brought to California from Australia.  True Gardens of the Gods:  Californian-Australian Environmental Reform 1860-1920 was written by an Australian historian, Ian Tyrrell.  Although we have read other accounts of the introduction of eucalyptus to California (most recently Jared Farmer’s Trees in Paradise), the perspective of an Australian on this history was new to us.

Those who despise eucalyptus often portray its introduction to California as a horrible mistake to be regretted and reversed.  Ian Tyrrell helps us to understand that there are actually good reasons for the introduction of eucalyptus that make sense in the context of the geographic and cultural realities of the historical period in which it was introduced. 

Historical geography of eucalyptus introduction

The gold rush in California and Australia occurred nearly simultaneously in 1849.  As these gold rushes played out, there was considerable travel of hopeful miners and their support structures between the two continents.  Naturally, they brought things with them that they considered useful to their enterprises and seeds of the Blue Gum were amongst their baggage from Australia to California.  Although there is speculation about the precise time and means of initial introduction, they remain theories.

Presently we think of Australia as being far away because our primary means of transportation is air travel and that trip is much longer than the trip to the East Coast of the US.  However, at the time of the gold rush, travel by ship was the primary means of transportation and the trip to Australia by ship was much shorter than the trip to our East Coast.  The trip around the horn of South America was both long and extremely dangerous.  In Richard Henry Dana’s Two Years Before the Mast, we share his terror during that voyage in the 1830s.

This shared experience of a gold rush meant that California and Australia also shared the environmental damage caused by the methods used to extract gold from the land.  Hydraulic mining was the primary method of extraction.  This method uses high-powered water pumps to erode riparian corridors to expose the gold in the soil.  Erosion is the result of this method of mining.

Ian Tyrrell tells us that the initial motivation for planting eucalyptus in California was to heal environmental damage caused by the gold rush.  Eucalyptus was an attractive choice for this task because it grows quickly and is well adapted to California which shares the same Mediterranean climate as much of Australia.  It seems ironic that the initial motivation for planting eucalyptus in California was to repair environmental damage, given that today the same trees are blamed for environmental damage by native plant advocates and mainstream environmental organizations such as the Sierra Club.

Our East Coast remained inaccessible to California until the completion of the transcontinental railroad in 1869.  The Panama Canal (completed in 1914) accommodated movement of large shipments of goods between the West and East coasts.

The cultural context

Tyrrell also introduces us to the intellectuals on both continents who were the environmentalists of the era of the gold rush.  George Perkins Marsh in America and Baron Ferdinand von Mueller in Australia were the environmental leaders of that period.  They were both committed to introducing species to their respective countries to improve the environment by creating “gardens of the gods”:  “These were pragmatic thinkers who leaned toward afforestation rather than preservation when the opportunity presented itself.  Early conservationists were, at bottom, advocates of a constructed landscape that would improve nature, not preserve.  In short, they were advocates for the garden concept.”   (1)

In California, the desire to import tree species from outside California was supported by the fact that much of California is naturally treeless.  Many species of trees that are native to California are not well adapted to many microclimates.  For example, if you want trees on a windward facing hill along the coast of California, you must plant a non-native.  So, cultural preference for introduced trees was supported by horticultural requirements of native tree species.

Timber famine

A second phase of afforestation with eucalyptus occurred towards the end of the 19^th century when there was widespread fear in America that we had severely depleted our timber resources and would soon experience a shortage of timber needed to build our new communities.  Eucalyptus was considered an attractive substitute for native timber sources because it grew quickly.  Plantations of eucalyptus were planted throughout California based on the belief that a valuable market for the timber was just around the corner.

This period of speculative investment in eucalyptus came to an abrupt end around 1914 for several reasons:

• Young eucalyptus does not make suitable lumber for building purposes.  We have since learned that eucalyptus makes valuable lumber at about 80 years of age.  We have also perfected kiln-drying techniques that produce high-quality eucalyptus lumber.
• The economic value of eucalyptus forest for timber was also reduced because of the limited ability of eucalyptus to regenerate naturally:  “The eucalyptus bore ‘seeds abundantly, but apparently the latter does not find, as a rule, the proper conditions for germination…Except with the aid of the hand of man, therefore, the eucalyptus will not sensibly encroach upon the treeless area’” (1)  (This is yet more evidence that eucalyptus is NOT invasive, as native plant advocates claim.)
• The demand for timber declined precipitously when alternative building materials were developed such as iron and cement.

Australia on the receiving end

As eucalyptus was introduced to California, Australians were importing the Monterey pine for timber.  Monterey pine is planted all over the world for timber.  It is the predominant timber species in New Zealand, but it never became as popular in Australia because it is softwood.  Eucalyptus is a hardwood and Australian’s developed a preference for hardwood that could not be satisfied with Monterey pine.  Unfortunately, that preference for hardwood has decimated the old-growth eucalyptus forests of Australia.

There is a lesson in this for us.  One of the advantages of introducing non-native trees is to protect native forests.  If we use our non-native trees to fulfill practical needs such as lumber and firewood, we are taking the pressure off the need to destroy our native forests.  Eucalyptus is still planted in many developing countries where firewood is still needed for fuel.  Wouldn’t we rather that these countries burn fast-growing eucalyptus than their native forests?

What can we learn from the Californian-Australian exchange?

Environmentalism is a cultural construct.  Its meaning has changed and will undoubtedly continue to change because culture is dynamic, just as nature is dynamic.  Mid-Nineteenth Century environmentalism was not wedded to native species, as is contemporary environmentalism.  Fifty years ago, when Rachel Carson’s Silent Spring was published, pesticide use was considered harmful to the environment.  Now we find that mainstream environmental organizations are actively promoting the use of pesticides to support their demands for eradication of non-native plants and trees.

We tend to look back at historical ways of doing things—such as planting eucalyptus—with a condescending attitude: “How could they be so stupid?”  Another way to look at the past is to look at the historical context in which those choices were made.  If we had sufficient knowledge of the historical context, perhaps those choices would make good sense.

Finally, if we look around the world at what is being planted today, we must acknowledge that planting non-native tree species often has practical advantages.  Non-native tree species might grow where native species won’t grow and where we need trees for windbreaks, visual and sound screens, erosion and pollution control, carbon sequestration, etc.  Or non-native tree species might protect native species by fulfilling specific needs that would otherwise require the use of native species.

As we often do on Million Trees, we reach the conclusion that more knowledge often results in more tolerance.  Thanks to Ian Tyrrell for these insights and to our friends for alerting us to this valuable resource.

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(1) Ian Tyrrell, True Gardens of the Gods:  Californian-Australian Environmental Reform, 1860-1930, University of California Press, 1999