The 3P’s of Healthy Trees

PRESERVE

Trees within our urban forest face stresses and difficulties that those growing in a natural forest setting do not. Trees need adequate soft ground surface in order to survive. Remember that tree roots spread out in all directions and that 80% of the roots are in the top 10 inches of soil.

If water and air are prevented from entering the soil by paving, interlocking brick or other hard surfaces, trees cannot absorb the moisture and oxygen needed for healthy growth. Maintain soft ground surfaces so that there will always be a home for future trees; paving over front yards for parking consumes potential planting space. Once paving is down, it’s unlikely it will ever come up!

PROTECT

Our urban forest provides a multitude of benefits. Large, mature trees have a greater leaf surface area, and therefore offer the greatest benefits in terms of cooling temperatures and improving air quality. Protecting these trees is essential to maintaining the benefits we receive from our urban forest. The bark of a tree acts as a skin, protecting it from invasions of pests and disease. Damage to the bark opens wounds that may make a tree vulnerable. Never attach, tie or nail anything to your tree.

Keep lawn mowers and weed-whackers far from the trunk; lawn-mower blight is the most common urban tree disease! A wide circle of mulch around the base of the tree can help prevent this. It is also important to protect your trees during construction. Fence off an area as large as possible around the tree and mark it with brightly coloured flags.

Remember that it’s not just damage to the trunk and branches that you need to prevent. Root damage or loss is often the greatest danger to a tree’s health. Above ground signs of root damage may not appear for a year or two, but often have serious, if not fatal, results for the tree.

Pruning is not as simple as cutting off the branches you don’t want. Often people think their tree needs to be “thinned out” or “cut back”. This is not usually the case. A tree allowed to reach its natural height and form will be much healthier. When pruning is required, either to maintain structural integrity, or to avoid power lines or other obstructions, it must be done correctly. Proper technique will prevent entry points for pests and disease. Pruning can also be dangerous, to yourself and to homes and individuals around you. Major pruning should be left to qualified arborists.

Monitoring your tree’s health regularly is important. Prevention is the best policy when it comes to pests and disease. A tree that has adequate growing space, moisture, light and nutrients will be much less vulnerable to attack. When you do see a problem, identify exactly what it is before treating it. Leaf damage is not necessarily a cause for alarm. Boring insects are more serious as they open wounds in the bark. When in doubt, consult an arborist to determine the problem before taking action.

PLANT

Planting new trees is essential to maintaining a continuous canopy cover. Remember that it takes years for trees to reach maturity so planning ahead is important. Planting the right tree in the right place is key to your satisfaction as well as to the tree’s long-term tree survival. Once a tree is planted, it does not take kindly to being moved!

Assess the conditions of your yard including light, soil type, moisture, and available soft ground surface (grass or garden, as opposed to paving or interlocking brick). Research the species that will thrive under your site conditions and try to select a native species. Imagine the tree at its full height and spread, and ensure that there will be no conflicts with structures or other trees in the future