Common Tree Health Issues
When looking at the health of the trees on your property, it is important to realize that even the healthiest trees can fail at some point. Tree death is inevitable, but by being proactive, there are measures you as a homeowner can take to prolong the life of your trees and to treat them should they appear stressed. 

Forest health, and tree health in particular, can be impacted by any number of variables that are biotic (living factors) or abiotic (non-living factors).

Examples of Biotic tree health stressors:
  • Fungi (Did you know there are over 8,000 types of known fungal species that cause plant health disease?) 
  • Bacteria
  • Insects
  • Viruses
  • Weeds
  • Microorganisms
  • Humans
Examples of Abiotic tree health stressors:
  • Water Stress (Floods/Drought)
  • Temperature Stress (Extreme Heat/Extreme Cold)
  • High Winds
  • Heavy Ice
  • An excess amount of Fertilizers and/or Pesticides
  • An imbalance of necessary micronutrients in the soil
  • Salt/Brine
  • Mechanical Damage (Weed trimmers damaging the bark of young trees, Mowers gashing exposed roots, Machinery and Vehicles compacting soil and/or damaging bark accidently)
With The Hideout being located in a glaciated portion of Pennsylvania, many of our tree’s are especially susceptible to heavy winds, ice storms/heavy snow, and flooding, all of which are abiotic factors.

Red and Sugar Maple branches, in particular, are very prone to breakage from heavy ice storms. Areas within the development with soil that retains excess water do not hold root systems as readily as they would in well-drained locations. Unfortunately, not many pro-active or preventative measures can be taken to combat non-living factors and their impact on overall tree health.

Defoliators, an adult or larval insect that strips away leaf matter from a tree or shrub, are prevalent in this part of the state and are not just found in our particular community. Common defoliators found within The Hideout are:
*Forest Tent Caterpillars
*Northern Tent Caterpillars
*Gypsy Moths.
*Fall Webworms

The Hideout actively monitors the populations of three of these defoliators on a yearly basis each fall in collaboration with the National Gypsy Moth Monitoring Group. Their yearly assessments of 98 sites established throughout the community help keep track of defoliator populations year to year and are vital when planning treatment measures to combat the next years hatch of each species.

Graph courtesy of:,_forest_tent_caterpillar_and_gypsy_moth_(e2299).pdf

Other insects to be mindful of are:

*Emerald Ash Borer (EAB)

*Hemlock Woolly Adelgid (HWA)

*Spotted Lanternfly (SLF)

Some preventative measures may be taken by homeowners, such as systemic pesticides or biological controls, to help reduce or eliminate these particular pests from negatively impacting certain species of trees on your property.

EAB, HWA, and SLF are all harmful to trees/plantings, and if seen, should be immediately addressed by contacting a certified arborist or tree care professional of your choosing.

Here is what to look for with each of these three insects:

Emerald Ash Borer, Agrilus planipennis

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Hemlock Woolly Adelgid, Adelges tsugae:
White fluffy masses on the undersides of conifers, specifically Hemlocks and Spruces.

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Click here for more information on Hemlock Woolly Adelgid in The Hideout

Spotted Lanternfly, Lycorma delicatula:

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If you think you may have Spotted Lanternfly on your property, immediately contact The Hideout’s Environmental Manager for a site visit by calling 570-698-4100 x122 or send our staff an email at, Tues-Sat 8am-4pm.

Click here for more information on Spotted Lanternfly

Aside from insects attacking trees, which is almost unavoidable, many trees are susceptible to a number of soil-based pathogens that often result in internal disease or decay. Three key components are necessary for disease to develop within a tree:
  1. A pathogen (the disease-causing agent)
  2. A plants susceptibility to a particular pathogen (Some species of trees may be resistant while others can be highly susceptible)
  3. An environment suitable for disease development (If a particular tree species is planted in a location that is not conducive to its survival needs, it is almost always destined to fail at some point)
It should be noted that different species of trees will be more or less vulnerable to different types of diseases. Some diseases are species specific, so properly identifying your tree is the first step in determining if it is being impacted by a particular problem. Some tree disease causing agents are infectious, such as fungi, protozoa, viruses, and bacteria. However, some disease-causing agents may be non-infectious, such as compacted soil, nutrient deficiencies, temperature extremes, vandalism, pollutants, and fluctuations in a soil’s moisture content.  

Some of the most common tree diseases in Pennsylvania are:
  • Dutch Elm Disease (Fungus. Tree should be removed immediately if confirmed)
  • Oak Wilt (Fungus. Targets Red Oaks in particular. Tree should be removed immediately if confirmed)
  • Anthracnose (Fungus. Attacks several species but rarely kills with the exception of Dogwood)
  • Maple Decline (Biological/Environmental. Targets Sugar Maples in particular, which should be removed if confirmed)
  • Verticillium Wilt (Fungus. Targets Maples, Redbud, Catalpa, and Goldenrain Trees in particular.)
  • Fire Blight (Bacteria. Only affects members of the rose family, including Mountain Ash, Hawthorn, Crabapples, Apples, and ornamental pear trees. Can be controlled via pruning.)
  • Root and Butt Rots (Fungi. Armillaria, Ganoderma lucidum, and Inonotus dryadeous. Tree should be removed immediately if confirmed)
Here at The Hideout, Colorado blue spruce and Norway spruce, for example, are highly vulnerable to a variety of issues such as Cytospora canker, which is a soil based defoliating fungus. Needlecasting (needle loss), tip blight, and needle discoloration are often indicators that your conifer is experiencing some sort of stressor.

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Beech bark disease is also common within The Hideout and is caused by the fungus Nectria coccinea var. faginata.  Beech scale insects feed on beech trees, leaving open wounds that allows entrance of the fungus.

Photos of Beech Bark Disease: Images courtesy of

Photos of Birch Canker Rot. Image courtesy of

Sapsucker/Wood Pecker Impact. Sapsuckers are a subspecies of the Wood Pecker family, and unlike their Wood Pecker relatives who create large holes in trees in search of wood boring insects, they are after the tasty sap just below the bark. You’ll know if a sapsucker is attacking your tree if you see a series of holes in horizontal and/or vertical rows.  

Photo of Sapsucker damage. Image courtesy of

As tree’s mature, they become more susceptible to a number of diseases and fungal attack. One particular issue with older trees or trees living in routinely wet areas that are water intolerant, is that of internal/heart rot, where the tree rots from the inside out due to excess water intake and loss of oxygen uptake through the root system.

Open Cavities/Wounds:
It’s not uncommon to see tree’s with small or large voids in them. These openings, known as cavities, develop over time from a wound of some sort.

Did the bark of your tree get accidently struck/removed by a weed wacker, or brushed up against by machinery during a construction project?

For fresh wounds, remove/peel away the damaged bark, leaving/exposing young healthy looking portions of wood. There is no need to apply a wound dressing, as they have been found to not be very beneficial by many certified arborists and can actually cause more issues.

For older wounds that just happen to get discovered, remove any dry/loose bark back to where new wood is visible surrounding the edges of the wounded area.

The trees response to a wound is to wall it off through a process known as compartmentalization. Many people think that trees heal themselves, when in reality, all they are doing is sealing off and isolating areas of decay to protect the rest of the tree.

If less than 25% of the bark around the trunk of the tree has been wounded by some means, it will generally recover.

Young, vigorous trees, almost always recover from wounds via the compartmentalization process where new growth occurs at the site of injury and gets added on to sound wood. Older trees, however, may have a difficult time responding to damage and are very susceptible to an immediate decline in health as decay causing fungi enter the wounded area.

So, does your tree have a cavity? If so, do not attempt to fill them with anything. In most circumstances, you need not remove a tree based on the presence of a cavity as the surrounding wood is most likely still healthy and transporting nutrients and water up and down the tree, satisfying its requirements for life. The tree is, however, considered compromised and is not as strong as it would be if it were 100% healthy. As such, it may fail during harsh weather conditions such as storms with high winds or under the weight of heavy ice.

 Many animals find tree cavities as highly desirable homes such as wood ducks, owls, raccoons, and opossums to name a few, so take their potential nesting site into consideration before committing to the removal of the tree.

When in doubt, have a certified arborist or tree care professional of your choosing assess your tree’s cavity or other concerning characteristics for advice.

Fruiting bodies: Fungi resembling mushrooms that are growing on the exterior bark are almost always a sign that internal rot is occurring. By this point, the tree cannot unfortunately be saved and should most likely be removed. Consult with a certified arborist or tree care professional of your choosing when making these decisions however.

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When in doubt about the health of your tree, contact a Certified Arborist or Tree Care Professional of your choosing. Their site assessment can provide informative details on the options you should take to properly address whatever may be going on with your particular tree. Sometimes, and more often than not, by the time a tree service professional is needed, the tree may be too far gone for treatment to be effective and as such, the tree may be recommended for removal.