Ontario Trees & Shrubs website

Tree Identification - A Brief Guide and Overview


Here are a few simple steps to help you get started in identifying Ontario Trees & Shrubs



1. Is it a woody or non-woody plant?

  • A TREE or SHRUB is a plant that contains woody materials in its stems. The stem can live through the winter, and continue growing in the following year. They can be full-size trees, small trees, shrubs, vines, or small plants only a few inches tall, referred to as Sub-Shrubs.


2. Is it a TREE or a SHRUB?

  • A SHRUB is usually defined loosely as a small tree, usually with more than one main stem or trunk. It includes woody plants down to the smallest possible, even only a few inches tall - these are known as " sub-shrubs". Woody vines are also usually considered to be SHRUBS. The size criteria refers to the normal mature size of the plant. Thus, a young sugar maple is not a "shrub"!

  • A TREE is what we commonly think of as a tree - tall, and usually with a single trunk.


3. Is it a CONIFER or a DECIDUOUS tree?

  • CONIFERS are trees & shrubs with needles: pine, spruce, fir, cedar, juniper, and tamarack. They retain their needles year-round (except for Tamarack).

  • DECIDUOUS trees & shrubs are all others. The leaves of DECIDUOUS trees & shrubs die every autumn and are usually shed (some species retain some or all of their dead leaves until the following spring).

4. Deciduous: Is it ALTERNATE or OPPOSITE or WHORLED?

The terms ALTERNATE, OPPOSITE and WHORLED refer to the arrangement of leaves and twigs.

  • In an OPPOSITE-leaved tree/shrub, the leaves and stems are arranged along the stem in pairs.

  • In an ALTERNATE-leaved tree/shrub, the leaves and stems are arranged along the stems in an alternating fashion.

  • In a plant with WHORLED leaves, the leaves are arranged the same as for opposite-leaved plants, except there are usually more than two leaves in a group. In other words, where there would be a pair of leaves, there are instead three or even more. Note that plants that have whorled leaves often have quite a few opposite pairs as well. For this reason species with whorled leaves are included with opposite-leaved species.

Note: Opposite-leaved trees/shrubs can appear to be alternate at times, but you will always find an opposite pair of leaves or twigs somewhere on the plant. However, alternate-leaved trees/shrubs will never have any true opposite pairs of leaves or twigs.

TREES: The only OPPOSITE-leaved trees in Ontario are Maples, Ashes, and Horsechestnut.
Most trees are ALTERNATE-leaved trees.

SHRUBS: There are many opposite and alternate-leaved shrubs in Ontario.


5. DECIDUOUS: Does it have COMPOUND or SIMPLE leaves?

  • COMPOUND leaves are those that are made up of smaller leaflets, usually 5 or more, sometimes as many as 13-15 or more.

  • SIMPLE leaves are the usual single leaf.



In Ontario:

  • CONIFERS: Pine, Spruce, Fir, Hemlock, Larch/Tamarack, Cedar, Juniper


    • OPPOSITE, COMPOUND-leaved: Ash, Horsechestnut, and one species of Maple

    • OPPOSITE, SIMPLE-leaved: Maple (except one species)

    • ALTERNATE, COMPOUND-leaved: Walnut, Hickory, Kentucky Coffeetree

    • ALTERNATE, SIMPLE-leaved: all the rest