Drought Stress

Urban tree

Basement foundations, driveways, utilities, and streets restrict the root system and available resources. In the urban environment grass competes with trees for water and minerals. This significantly reduces the capacity of a yard to support a tree.

Why Urban Trees are Drought Stressed

Less Water is Available – Unless regularly irrigated, urban trees generally have less water available than their counterparts in natural settings.  Why?  Paved surfaces encourage runoff instead of absorption, and these surfaces cause higher soil temperatures and faster evaporation of rainfall.

Restricted Root Space – Building foundations, streets, driveways, and other obstacles limit the expansion of tree roots and significantly reduce the amount of water and minerals available to the tree.

Compacted Soils – Urban soils are usually compacted from human activity, and this creates stress for a tree.  Soils can become difficult for roots to penetrate, and compacted soils hold much less water and oxygen which are critical for tree health.

Competition – Most yards have a dense layer of turf that surrounds a tree.  Turf aggressively competes for minerals and water, which reduces their availability to other plants.  Adding several inches of mulch within the dripline of the tree reduces competition with turf, keeps the soil cooler, and holds more moisture.

urban vs natural soil

Urban soil on the left, natural soil on the right

Slower Growing Trees

A common myth about trees is that a faster growing tree is healthier than a slower growing tree.  The truth is that slower growing trees will outlive trees that grow faster, especially in situations such as yards where space and resources are limited.  The chart below shows some important differences between a tree growing relatively faster or slower.


Slower growth is beneficial

An Integrated Approach

When caring for urban trees it is important to make a thorough evaluation of the site to accurately diagnose all stressing agents and tailor your recommendation to the specific circumstances.  These must be dealt with so that your tree can live to its fullest potential. Contact us for a comprehensive maintenance program.

Benefits of Cambistat for Urban Trees

Cambistat is a soil applied product that is absorbed through the roots. Cambistat gently slows the growth of trees, allowing the tree to redirect some of its energy from canopy growth to defense chemicals, fibrous root production, and other uses. The resulting reallocation of energy makes your tree healthier and more durable.

Drought is a major cause of tree death and decline in the urban landscape. Research shows Cambistat increases drought resistance by helping the tree reduce water losses during dry, hot periods.

Cambistat changes some important physical traits of leaves. Leaves of treated trees tend to be greener (higher concentrations of chlorophyll) than untreated and have an enhanced protective barrier (thicker leaf surface and denser surface hairs).

Untreated oak tree leaves

Untreated oak tree leaves

Oak tree leaves after treatment

Oak tree leaves three years after treatment


Contact us to schedule a consultation with a certified arborist.

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