Tree Species Selection


 

When planting a tree or shrubs there are many things that should come into play. Site conditions – climate, soil, physical limitations à functions – engineering, aesthetics, landscape architecture, climate control à attributes – of the species. Which leads us back to soil conditions. This is a cycle.

Native vs Exotic

Native – proven for climate, less maintenance, and fewer pathological

Problems.

- there are many cultivars, varieties, and hybrids these days that allow for a wide range of selection to choose from that look exotic and have great advantages.

Exotic – must have a good reason.

Climate

Most common used tool to match plants with climate is the hardiness zone maps or seed zones. This is very important to make sure your tree matches your location.

Site

Soils:

Forest soils – are favoured for planting

urban soils – artificial by: modifications, compation, and design. This will

really influence your species selection.

Physical Limitation:

Below Ground - need a root system that can handle the underground

condtions

- soil volume and density

- H2O infiltration reduced due to paved surfaces, compacted

soils which will hinder the trees growth and health.

Above Ground – consider crown shape and size at maturity (or by regular

maintenance

- overhead utility wires, buildings, road ways and

pedestrian areas, lights security concerns

Function

Consider primary function and match species to fit. This includes: wind breaks, noise abatement, trespass control, accents and cover, crown shape and available space do not impede shape. Consider size at maturity and you can pick a cultivar or hybrid to fit most spaces.

Attributes

Many considerations including:

- fruits or flowers – odours, colour, size, shape, clean ups required, attract

insects (bees , wasps)

- bark characteristics – interesting/attractive (London plane, white birch)

- root systems – invasive roots may damage septic systems, pools,

sidewalks, walls etc. (poplar, willow, silver maple)

- growth rate

- pathogens and treatments

- light tolerance (shade tolerant, intermediate, shade intolerant species)

Success in urban situations depends on three things

1.    the right choice

2.    good growing conditions (soil preparation at time of planting is very important)

3.    after planting care and protection