Monitoring Trees for Invasive Insects & Disease

Why is it important to monitor tree health?

Trees are an important aspect of all of our lives. They provide many essential environmental, economical and societal services. Trees provide shelter and shade, reduce noise, wind, and erosion, cool air temperatures, support storm water management, provide wildlife habitat, absorb pollutants and carbon dioxide, support our economy and carry cultural significance among other significant benefits.

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Source: Nature Conservancy

Monitoring trees for signs of invasive species is an efficient way to discover new populations before they become established and threaten native populations. While tree health can be affected by other factors besides invasive species, a combination of signs should prompt a closer inspection of the tree to be sure.

Where can I help monitor tree health?

Trees are part of our everyday lives and casual monitoring can be done by everyone, regardless if you own property.

Hikers

Our island’s trails are travelled by many and are susceptible to an increased rate of introduction. You can help support monitoring efforts by monitoring your favorite trail. Monitoring ensures that these trails can be enjoyed for years to come and help reduce hazards and maintenance on trails.

Campers

Firewood is one of the main pathways insects and disease are introduced from outside areas. Finding signs of invasives in campgrounds could mean you are catching an outbreak early. So, when you’re out for a walk around the park’s grounds, consider inspecting tree health along the way.

Homeowners

The majority of PEI is privately owned and, therefore, it is likely introductions in these areas could go unnoticed unless landowners do some monitoring. Monitoring can prevent intensive maintenance operations down the road. Consult an arborist to protect the economic and environmental value of your land.

City Residents

Cities can be hot spots for new introductions. Charlottetown has a tree database named treekeeper for all of its street and park trees, and it is available to the public. If you’re interested in monitoring for specific tree pests you could use it to map a route and monitor specific tree species (Like Emerald Ash Borer and True Ash Trees).

Signs of Tree Decline and, possibily, Invasive Species

Leaf Mining
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Photo Credit: Green Thumb Photography
Leaf Mining
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Photo Credit: Green Thumb Photography
Leaf Mining
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Photo Credit: Green Thumb Photography
Galleries
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Photo Credit: Green Thumb Photography
Defoliation
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Photo Credit: Green Thumb Photography
Defoliation
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Photo Credit: Green Thumb Photography
Defoliation
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Photo Credit: Green Thumb Photography
Defoliation
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Photo Credit: Green Thumb Photography
Epicormic Shoots aka suckering
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Photo Credit: Green Thumb Photography
Epicormic Shoots aka suckering
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Photo Credit: Green Thumb Photography
Canker Cracks
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Photo Credit: Andrej Kunca, National Forest Centre – Slovakia
Cankers
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Photo Credit: Green Thumb Photography
Cankers
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Photo Credit: Green Thumb Photography
Flagging
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Photo Credit: John Hartman, University of Kentucky
Crown Dieback
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Photo Credit: Green Thumb Photography
Pupae & Cocoons
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Photo Credit: Green Thumb Photography
Pupae & Cocoons
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Photo Credit: Green Thumb Photography
Egg Mass
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Photo Credit: Green Thumb Photography
Egg Mass
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Photo Credit: Green Thumb Photography
Egg Mass
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Photo Credit: Green Thumb Photography
Exit Holes
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Photo Credit: Green Thumb Photography
Exit Holes
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Photo Credit: Green Thumb Photography
Fungal Fruiting Bodies
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Photo Credit: Green Thumb Photography
Fungal Fruiting Bodies
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Photo Credit: Green Thumb Photography
Discolored Leaves
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Photo Credit: Green Thumb Photography
Discolored Leaves
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Photo Credit: Green Thumb Photography
Discolored Leaves
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Photo Credit: Green Thumb Photography
Discolored Leaves
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Photo Credit: Green Thumb Photography
Discolored Leaves
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Photo Credit: Green Thumb Photography

Identifying the culprit behind a tree's decline

First identify the tree species on which you discovered the sign. Many insects or disease are host specific and this could help narrow down which species you may be dealing with.

Next, examine the tree in detail. Start from far away and begin by looking at the crown and working your way down, does it seem to be in good health? Then get up close and examine the tree's trunk. Are there exit holes, oozing sap or any other abnormalities? Don't forget to look up when under the tree and look into the canopy. Take notes and pictures of any sign.

Next do a little research online, starting with what tree species you found it on and then narrowing it down with what signs you observed. If you are confident in your ID, you can make reports in EDDMapS or you are welcome to send us an email if questions remain.

Steps to Determine Why a Tree is in Decline: Example

  1. Notice a visibly declining tree from afar.
  2. Identify the tree, Black Ash (Fraxinus nigra)
  3. Make notice of all signs of decline:
    • Exit Holes, "D" shaped
    • Galleries
    • Crown dieback
    • Bark deformities
    • Yellowing of foliage
    • Vertical cracks in the trunk
    • Woodpecker damage (a sign the tree may be infected with larvae)
    • Epicormic branches (shoots growing in abnormal places like base of tree or from mature branches)
  4. Use a Search Engine and input the tree’s species: Black Ash and two at least two signs: woodpecker damage, crown dieback.
  5. Sift through the results until you find a credible source, in this case the top result returned is “signs and symptoms of infestation by the emerald ash borer”.
  6. Contact your local Invasive Species Council as Emerald Ash Borer is a Species of Concern. *If your search engine results turn up no results, take photos and consult your local Invasive Species Council for direction.
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Source: Treesaregood.org
Next: Learn about the reporting process →