Plants are susceptible to environmental stress just like humans are. Drought, drowning, heat, and cold can all damage trees and may even be mistaken for insect or disease damage.

Animal Activity

Trees are essential to the existence of many species for food and shelter or just as a good scratching post. The activities of birds and mammals may therefore result in the damage or destruction of trees.

Climate

Here in Grande Prairie, we live in one of the northernmost agricultural areas in the world.  This presents some special challenges to us in choosing the proper ornamental trees, shrubs and plants for our yards and gardens.  It may be tempting for you to try and push the climate envelope and plant trees not fully hardy to Zone 2b.  However, sooner or later low winter temperatures or an early frost will cause severe winterkill or may even kill your tree outright.  In order to have a landscape full of healthy plants, use only what can live in this area.

Human Activity

Soil

Native soil variability means that a given tree species - although hardy to this climatic zone - may not excel equally at all locations in the city. Native plants growing on site are often an indicator of soil suitability for landscape plants. Plants should be chosen that tolerate local soil conditions.  If you are unsure of soil conditions on your growing site, or if you are having difficulty establishing plants, a soil test from an accredited lab may help.