A Technical Guide to Urban and Community Forestry, Basic Horticultural Principles Basic Needs Plant growth is a very complicated process, but it is not necessary to understand all the intricate details in order to successfully manage the urban forest. However, understanding the basic requirements of tree growth will help. Soil is a reservoir for nutrients and moisture, and provides mechanical support.
Sunshine furnishes heat and light.
Plants in the wild obtain these basic needs from a complex, but finely balanced biological system. Cultivation often disturbs the natural balance. Any factor in the plant's environment that becomes less than optimum will limit its growth. Naturally, quantity is important, but quality also affects the vigor of trees. Air pollution, construction activity, and soil compaction place stresses on trees.