Sustainable Trees for Sustainable Cities

The idea of sustainable cities is linked to an older concept of sustainable plant communities. The theoretical basis for both is a closed system where everything is continuously recycled. Natural resources are renewed rather than depleted. In undisturbed natural areas a kind of sustainability is achieved through the natural cycles of the biosphere. However, this kind of sustainability for trees in the city cannot be achieved because the natural cycles have been interrupted there. Continuity of urban trees depends on human intervention.