Tree Protection Guidelines

Trees enhance the appearance of our streets and parks. They help cool and clean the air, as well as provide screening and shade. Trees can increase property values and attract tourism in our communities and business sectors.

To help protect City trees, the City of Ottawa has in place a Trees By-law. This by-law addresses the protection, maintenance, and control of trees on highways and City property and sets out the responsibilities for persons carrying out work in the vicinity of a City-owned tree. The City of Ottawa's Road-Cut By-Law also has clauses that address the protection of City trees.

The tree's support network of roots lies within the first two feet of soil. In addition to stability, they provide food and water to the tree for survival. When roots are cut or damaged by digging or soil compaction caused by heavy equipment, serious injury or death can occur. Injury to the tree may not become apparent for days, weeks, or even years.

The Trees By-law requires that trees be properly protected during construction work. If a City tree is damaged or removed, the person responsible must pay the cash value of the tree as determined by the International Society of Arboriculture Tree Evaluation guide. In addition anyone convicted of contravening any provision of the Trees By-law can receive a fine of up to $5000.

The contractor must protect trees
Trees, especially their roots) are very sensitive to disturbance. Soil compaction and vibrations from construction equipment can cause unnecessary damage to roots. The Trees By-law requires that contractors working near trees must:

• erect a fence at the critical root zone (CRZ) of trees;
• not place any material or equipment within the CRZ of the tree;
• not attach any signs, notices or posters to any tree;
• not raise or lower the existing grade within the CRZ without approval;
• tunnel or bore when digging within the CRZ of a tree;
• not damage the root system, trunk or branches of any tree;
• ensure that exhaust fumes from all equipment are NOT directed toward any tree's canopy.

What is the critical root zone (CRZ) of a tree?
D = diameter of trunk in centimetres
D x 10 cm = Critical Root Zone

The critical root zone is established as being 10 centimetres from the trunk of a tree for every centimetre of trunk diameter. The trunk diameter is measured at a height of 1.2 metres for trees of 15 centimetres diameter and greater and at a height of 0.3 metres for trees less than 15 centimetres in diameter.

What about utilities?
The Trees By-law applies to all contractors working for a public or private utility.

What if a tree is damaged or must be removed?
The contractor must obtain approval from the City before removing any tree on City property. If a tree is damaged or removed, the contractor will be required to:

• pay the cost of repairs and labour or pay for the removal;
• pay the value of the tree removed;
• pay the cost of a replacement tree and its installation.

• The contractor should be familiar with the Trees By-law and the Road Cut By-law prior to commencing any work.
• The contractor must obtain all permits and approvals prior to the start of construction.
• The contractor must call a City Tree Inspector when work is required near a City tree.

For more information on the City of Ottawa's Tree Protection Guidelines, please contact:

City of Ottawa 24-hour Call Centre at 580-2400
e-mail to: forestry@ottawa.ca