Signs of a Healthy Forest

A tree health checklist can help you determine how healthy your forest is and what action you can take to improve woodland health.

Credit: Flickr's Lon&Queta

When you go in for a checkup, the doctor doesn’t just look at one part of your body—he or she evaluates every system to make sure you’re OK.

Giving your woods a checkup is very similar. You have to check every system within your forest to know if the whole is in balance. That means inspecting individual trees, looking at the diversity of the whole forest and the plants and animals that live in it, and studying the cycles at play in your woods. Together, these elements give you a picture of your forest’s overall health.

Let’s start with individual trees. What signs should you look for?

Your Tree Health Checklist

[make it clear to the landowner that this checklist is printable and can be taken into the field; also make it clear the bullets are checkboxes]


What you see	What it means
Ragged leaves with holes	Insects are feeding on the leaves
Black or brown leaves	Stem or leaf disease; could also be sign of frost or salt damage
Spots or bumps on the leaves	Insects and mites could be damaging the tree
Twisted or malformed leaves	Herbicides, insects or disease are damaging the tree
Leaves are changing color before fall	Trunk or root damage; drought or pollution could also be the cause
Branch decay	The tree may have unhealed wounds
Peeling or broken bark, or holes in the bark	Trunk wound, canker disease, or damage caused by humans or animals
Dying branches on one side of the crown	Root decay, root injury or internal stem disease, insect attack
Canker (a dead section of trunk or branch)	Fungal infection
Splits in the tree	Broken branches, wind damage or exposure to severe or dry conditions
Hollows in the tree	Water entering the tree through old wounds and fueling fungal wood decay
Fungi or mushrooms growing on the tree	Internal decomposition of the wood by fungi
Green or brown spots on needles	Air pollution
Red needles	Possible insect infestation

When going into your woods for their checkup, bring some colored chalk to mark trees as healthy or sick as you go. Note that 10 percent or more of the tree should be affected to count it as damaged or diseased.

As you can see, any one sign could mean a variety of things, and only a professional forester can know for certain what’s to blame. So if you notice several trees in your stand have signs of disease or damage, consult with a professional to determine your next steps.

But the health of individual trees doesn’t tell the whole story of your forest. The diversity of your woods—the mix of plant species and habitats there—is just as important.