The dynamics of arboreal history sits between human life span and geologic time such that changes will be imperceptible from a daily vantage point. Individual trees can live hundreds to thousands of years; ecosystems such as forests, grassland, wetland and deserts can persist for millions.
The urban systems are geologically novel and the Los Angeles landscape holds many early artifacts of human activity. What I see in its flora are the records of this history. Trees are silent sentinels individually bearing signs of human intention, and as an aggregation become markers on the landscape. The low-lying basin habitats that existed before California became a state over 150 years ago have been replaced with newly naturalized vegetation springing up between the networks of roads and buildings as both wild and designed greenscapes.
What is familiar in the Los Angeles flora becomes a starting point when looking at ornamental trees that line the streets and shade the parks. Palm trees for example are not indigenous to the region but it is an icon and symbol of the exotic and leisure of this temperate Mediterranean city. Eucalyptus trees are also not indigenous but brought in as resource husbandry for lumber, pulp, and shade. How do these two trees and affect the original ecosystem? How do they affect our aesthetics? How do we effect their condition? What is interesting is that the current distribution of the eucalyptus is mostly in the southern hemisphere in Australia and New Zealand but the oldest fossil record dates to over 50 million years ago in Argentina. Geological forces caused slow extinction and man-made forces can reincarnate. We are all migrating and transplanted organisms and infrastructure living in changing habitats.