trees

The Slow Storm: Tree Mortality in CT from Invasive Insect Pests

By Thomas E. Worthley, UConn Associate Extension Professor, Forestry

During the early summer of 2018 it became apparent that numerous trees throughout eastern and southern Connecticut did not produce leaves this spring, having died sometime during the winter. While it is not unusual to lose a tree or two to natural causes here and there at any time of year, the massive scale and extent of oak tree (Quercus spp.)mortality during the winter of 2017 to 2018 due to the combination of recent gypsy moth (Lymantria dispar) infestations and associated drought conditions is notable and concerning. Combined with the anticipated loss of ash trees (Fraxinus spp.)in many areas due to the invasive emerald ash borer (Agrillus planipennis), which has been moving across Connecticut from where it was initially found in northern New Haven County, the sheer numbers of LARGE standing dead trees throughout the state presents what might best be described as a slow-moving environmental disaster.

Emerald ash borer first appeared in the Connecticut landscape in 2012 after a slow but relentless spread across the country and has been gradually decimating the ash population in Connecticut since that time. A long period of detection sampling and information dissemination has raised the awareness about this pest with professionals, elected officials and members of the public. We’ve known it was coming and in many ways arborists, foresters, town staffs, CT-DOT and utilities have been preparing for it.

The sheer degree and extent of oak tree mortality in southeastern Connecticut, on the other hand, was unexpected and has overwhelmed many homeowners, Tree Wardens, foresters and others.

Many adult citizens recall severe gypsy moth defoliations during the early 1980s. At that time the forest took on a winter-like appearance across a large portion of the state for a couple summers in a row as the population of gypsy moth caterpillars exploded into our vast oak forest canopy. The caterpillar population then crashed as quickly as it grew (due to caterpillar disease factors) and since that time fungal and viral diseases, among an assortment of other caterpillar predators, has kept the population in check. Those of us that take note would see only spot infestations in various locations since that time. During the 1980s, as expected, trees produced a second set of leaves each of those summers, and while there was some mortality, the severity was not as intense or as wide-spread.

Also, in some places an additional secondary mortality event is evident. Early and mid-season browning of leaves on individual trees that leafed-out and seemed fine this spring indicates that other pests or diseases are continuing to affect previously stressed trees. Among the factors that might be responsible are two-lined chestnut borer, a native pest, and armillaria fungus, also known as “shoestring” fungus.

The current problem is two-fold:

First, very large dead trees with wide spreading crowns are very numerous along some roadways in eastern Connecticut. These conditions seem quite variable. One can drive several miles along a local road and not see any dead trees and then pass a stretch that has as many as 30 or 40 dead trees per mile. Implications for public safety are apparent.

Second, there are forest stands throughout the affected area experiencing severe mortality rates. This author has been in stands ranging from a few more dead oaks than usual to as much as 80-90% canopy loss. And these are not necessarily the poor-growing, stressed and uncompetitive trees, but are often tall magnificent trees with large crowns that seemed most robust and healthy. Assessment efforts are underway to ascertain the degree and special extent of mortality in forest stands.

From a timber value standpoint the potential for severe economic loss for woodland owners is potentially staggering. The total volume of commercially valuable timber, standing dead, that might be salvaged is beyond the capacity of the timber industry to address it. From a public safety point of view, the numbers of dead trees that have the potential to ultimately impact roadways and power lines is well beyond the capacity of property owners, town budgets, CT-DOT and/or utilities to address.

Initial data from a random sampling of ninety miles of local roads in several towns from Sprague to Haddam has indicated an average of 18 dead roadside trees per mile, half of which can be categorized as high potential risk. This roadside tree mortality survey is continuing on more local roads in more towns. Additional survey data is being collected by a team from UConn.

Brooklyn road with dead trees Higganum road with dead trees

High-potential-risk trees photographed in Higganum and Brooklyn, CT in mid-June, 2018. Photos: Tom Worthley

During roadside tree mortality surveys, a tree will have been characterized as high potential risk if it is a large tree, with slight to severe lean toward the road and/or with most of its limbs and branches over the road, such that if not removed, half or more of the mass of the tree will, over time, eventually drop in the road. A sampling of roads in East Haddam, for example, where mortality from both gypsy moth and emerald ash borer is occurring, indicated 134 such high-potential-risk trees on 21 miles of road (smaller, less-potentially risky trees are not included, but are much more numerous) for an average of about 6 problem trees per mile. At a cost of somewhere between $500.00 and $1000.00 per tree, just those 134 trees will cost upwards of $67,000, perhaps over $100,000 for removal. State data for local road mileage estimates 118 miles of local roadway in East Haddam, the problem dwarfs the $25,000 annual budget the town allocates for tree issues. One or two or a half-dozen dead trees along roads in town might be “acceptable” risk, but if the sampling data is accurate and we estimate over 700 potentially problematic trees in town, it will (if not addressed) become downright risky to drive or walk in the community over the next few years.

Key are the phrases “potentially problematic” and “over the next few years”. Unlike ash trees, dead oak trees do not decay and disintegrate in a short period of time. The first heavy, wet snow will bring down small twigs and branches this winter, next summer, larger limbs and branches will decay and drop, a few at a time. Larger limbs and trunks of oak trees might retain some structural integrity for another 3 to 5 years, but eventually the root system will rot and, gravity being the law, the entire remainder of tree will topple in whichever direction it leans. The more severe the lean, the sooner it will happen. Liability for possible damage or injury, even a few years from now when gypsy moth is old news, is likely to rest with whoever owns or is responsible for the tree in question.

In July of 2018 two ad-hoc meetings were held by concerned stakeholders to exchange information and discuss roadside tree mortality. Attendees at these meetings included representatives from CT-DEEP, CT-DOT, Eversource, UConn, some town elected officials, CIRMA, Tree Wardens and members of the forestry and arboricultural communities. The discussion was wide-ranging and thorough. Major points of agreement amongst attendees included the following:

  • Roadside tree mortality presents a serious potential public safety hazard.
  • The scale and scope of the problem is beyond the capacity of CT-DOT, Eversource and many towns to address the issue.
  • Time is of the essence. Dead trees are unpredictable and dangerous for tree workers and timber operators, and become more dangerous the longer they stand.
  • Additional assessment data is essential, plans to continue that effort should be encouraged.
  • Emergency funding and logistical support should be sought. Is FEMA an alternative?

Recommendations for homeowners and landowners with dead trees near boundary lines or roadways are to obtain the help of an arborist or qualified tree service as soon as possible. Dead trees are hazardous trees and the owners of hazardous trees can be liable for damage or injury they might cause. The sheer number of trees that need attention has made it difficult to contract with arborists, so be persistent, but also be careful about engaging inexperienced or unlicensed contractors. Check references. A listing of licensed arborists can be found at the web site of the Connecticut Tree Protective Association, www.CTPA.org.

Woodland owners are advised to consult with a Connecticut Certified Forester about the condition of trees on their properties. Recommendations for management actions will vary depending on morality severity and size of that affected area. A listing of Foresters can be found at the CT-DEEP Forestry Division web page. Look for the “Certified Forest Practitioners” listing. Text within the document explains the roles and authorizations for different levels of certification, and is important to note. Landowners should be aware, however, that trees can lose some commercial value once they have died, and that stands with numerous dead trees to harvest are likely to be extremely dangerous to work, again potentially affecting value. Please do not attempt to remove or harvest dead trees on your own without proper personal protective equipment (hardhat, eye and ear protection, chaps) and some chain saw safety training.

Woodland owners with specific questions can contact me at thomas.worthley@uconn.edu.

Beaver Brook State Park in Chaplin with dead trees 

Severe canopy loss/oak mortality at Beaver Brook State Park in Chaplin – mid June 2018

Understanding Gypsy Moth Outbreaks

gypsy moths on tree
Photo: Tom Worthley

Gypsy moths (also known as the North American Gypsy Moth or the European Gypsy Moth) were imported to North America from Eurasia in 1869 for a silk production experiment. They have caused periodic defoliations in New England since then and particularly severe defoliations in the early 1980s and again in Connecticut and Massachusetts in 2016 and 2017. (Gypsy moths do not build webs – the webs you see in cherry trees are tent caterpillars.)

Female moths lay between 500 and 1,000 eggs that overwinter until spring when they hatch. Eggs are usually found underneath the bark scales of trees, on trunks, branches or other protected sites. Eggs last for 8-9 months before they hatch. Adults only live for about one week while they mate and lay eggs. Gypsy moth populations can persist with very low numbers for years but under the right conditions can have outbreak years where populations explode.

The caterpillars feed on leaves of most deciduous trees and many conifers as well. After feeding for some time they descend to the ground by means of silk threads to change size (molt). Silk threads and numerous hairs on the bodies of small, early-instar (stage) caterpillars allow them to be spread by the wind. These caterpillars change size three times before entering the pupal stage and maturity.

Gypsy moths only damage trees during the larval (caterpillar) stage when they are feeding on the leaves, and leaf-feeding and defoliation is the only type of damage they do. In high numbers they can completely defoliate the trees. One gypsy moth caterpillar can eat as much as eleven square feet of leaf area.

Most deciduous trees have the ability to re-set buds and produce a second set of leaves following defoliation.

dead caterpillars on tree
Photo: Tom Worthley

Coniferous trees do not have this ability. Multiple defoliations can be problematic for the trees. Gypsy moth caterpillars will feed on most tree and shrub species (500 total species!) but prefer oak and beech. Tulip trees (yellow poplar) are not affected. Pines and hemlocks are likely to die after one defoliation.

Multiple defoliations combined with drought are causing individual tree and stand-level mortality in some areas. Trees that have not “leafed-out” in 2018 can be seen in numerous locations around the state. In some places, large individual roadside trees and trees near structures that have died present potential future safety hazards. In forest stands on state and private forest lands, sufficient oak mortality can be observed to warrant consideration of forest harvesting activities to salvage timber value. Private woodland owners are well advised to consult with a CT-Certified Forester to evaluate their woodland conditions. (Links provided below.)

Since the 1980s, a fungus from Japan, Entomophaga maimaiga, has been keeping gypsy moth populations under control but during dry conditions the fungus is less active. Gypsy moth populations seem to explode when there are dry conditions during the spring and summer months.

Natural controls include:

  • Birds (limited effectiveness, small instars only)
  • Vertebrates (deer mice and shrews)
  • Invertebrates (ants and ground beetles, parasitic flies and wasps)
  • Viral Disease Wilt
  • Pathogens like Entomophaga maimaiga fungus

There are a few management tools available:

  • Bacteria-based treatments exists.
  • Soapy water sprays (horticulture soap/oils mixed with water).
  • Traps to catch adults.
  • Finding and destroying egg masses (too late for 2018).

Pesticides are not commonly used because of chemical toxicity and are impractical for entire forests. If used for an individual tree be sure to read the label.

On the UConn campus in Storrs the arborist crew will spray some campus trees using bio-based spray. Trees that don’t leaf out will be removed. Some salvage of dead trees in the UConn Forest will take place as appropriate for fuel wood and saw logs. Inspections will be done in early summer.

A Certified Forester should be consulted for stand-level management and a licensed arborist for individual trees near homes and buildings. More information is available from the Department of Energy and Environmental Protection: http://www.ct.gov/deep/cwp/view.asp?a=2697&q=589362&deepNav_GID=163 and the Connecticut Agricultural Experiment Station; http://www.ct.gov/caes/site/default.asp .

To find an arborist link to the CT Tree Protective Association, www.ctpa.org.

Article by Tom Worthley

Dealing with Storm Damaged Trees

By Tom Worthley, UConn Extension

 

tree down across road in Brookfield, Connecticut on May 15, 2018
Tree down in Brookfield, Connecticut on May 15, 2018. Photo: Jeremy Petro

On May 15, 2018, late in the afternoon, a striking example of one of those “severe weather events” we see quite often these days passed through my neighborhood in Higganum. Severe winds, downpours, lightning and thunder all were part of a wicked and deadly storm that ripped limbs from and uprooted trees, downed powerlines and damaged buildings and vehicles in other parts of the state. Images on TV news and social media of damage and cleanup efforts have been striking.

For my part, because of the sudden and severe nature of the winds, and the near-continuous display of lightning, I was as nervous I ever remember being about a storm event and the potential for damage to my humble little house from trees and limbs. Sure enough, one large limb, from the top of a large red oak, did get ripped off and came down about 20 feet from where I park my car. There is, of course, a mess of smaller twigs and branches as well. No real property damage, thank goodness, but it was close. The storm was over a quick as it began, and now, just like many folks around the state, I’m faced with a clean-up task. It’s not a real problem for me; that broken limb is at the edge of the woods and will make a nice neat little pile of firewood.

For many people, however, the task of cleaning up storm-damaged trees is not so straightforward and simple. Many damaged trees are huge and are left in precarious, unstable positions. Storm-damaged trees are fraught with abundant problems, dangers, and risks. Cutting, cleaning up and salvaging downed, partially down or damaged trees is one of the most dangerous and risky activities an individual can undertake.

In viewing the news reports, photos and social media posts I have been shocked and horrified by the personal risks that people are taking to cut up downed trees in cleanup efforts. Pictures of men operating chain saws in shorts and t-shirts, climbing downed tree limbs (and standing on them!) to cut them, working with no personal protective equipment, etc. – it can all be quite distressing for a person familiar with the potential danger. No professional arborist or logger I know does chain saw work without personal protective equipment – and these are the experts!

It cannot be emphasized enough that without personal skill and a thorough knowledge of equipment capabilities, safety procedures and methods for dealing with physically stressed trees, an individual should never undertake this type of work on their own. The very characteristics that make the wood from trees a great structural material can turn leaning, hanging or down trees into dangerous “booby-traps” that spring, snap, and move in mysterious ways when people try to cut them. They can cause serious and life threatening injuries. Just because your neighbor or relative owns a chain saw, it doesn’t make them qualified to tackle a large tree that is uprooted or broken. Contacting a Licensed Arborist, or Certified Forest Practitioner with the right equipment, training, and insurance, is the best alternative for addressing the cleanup and salvage of storm damaged trees, and avoiding potential injury, death, liability and financial loss.

That said, there are a few things a homeowner can do about trees that are damaged and/or causing other damage around a home site:

  • First, from a safe distance note the location of any and all downed utility lines. Always assume that downed wires are charged and do not approach them. Notify the utility company of the situation and do nothing further until they have cleared the area.
  • Don’t forget to LOOK UP! While you may be fascinated with examining a downed limb, there may be another one hanging up above by a splinter, ready to drop at any time.
  • Once you are confident that no electrocution or other physical danger exists, you can visually survey the scene and perhaps document it with written descriptions and photographs. This will be particularly helpful if a property insurance claim is to be filed. Proving auto or structure damage after a downed tree has been removed is easier if a photo record has been made.
  • Take steps to flag off the area or otherwise warn people that potential danger exists.
  • Remember that even if a downed tree or limb appears stable, it is subject to many unnatural stresses and tensions. If you are not familiar with these conditions, do not attempt to cut the tree or limb yourself. Cutting even small branches can cause pieces to release tension by springing back, or cause weight and balance to shift unexpectedly with the potential for serious injury. Call a professional for assistance.
  • Under no circumstances, even in the least potentially dangerous situation, ever operate, or allow anyone on your property to operate a chainsaw without thorough knowledge of safe procedures and proper safety equipment, including, at the minimum, hardhat, leg chaps, eye and hearing protection, steel-toe boots and gloves.

An assessment of the damage to individual trees, or more widespread damage in a forest setting is best undertaken by an individual with professional expertise. Homeowners should contact an Arborist to examine trees in yards or near to structures, roads or power lines. A Certified Forester is qualified to evaluate damage in the forest to trees and stands and advise landowners about the suitability of salvage or cleanup operations. The CT-DEEP Forestry Division can provide information about contacting a Certified Forester or Licensed Arborist. Check the DEEP Website, http://www.ct.gov/deep/cwp/view.asp?a=2697&q=322792&deepNav_GID=1631%20

or call 860-424-3630. Listings of Licensed Arborists can also be found at the CT Tree Protective Association web site, www.CTPA.org.

While a nice tidy pile of firewood from a tree that was damaged in a storm might be the silver lining, it is not worth the risk of injury to yourself or someone else when tackling a very dangerous task without the proper knowledge, equipment or preparation.

Gypsy Moth Update

gypsy moths on tree
Photo: Tom Worthley

Gypsy Moth Update from Extension Educator Tom Worthley: “On Friday, I observed these live adult female gypsy moths laying eggs along Chaffeeville Road in Mansfield. Obviously some caterpillars managed to survive the fungus and other predators and develop to maturity in some spots. If people are so inclined they could kill moths they can reach, (squirting the moths and egg masses with a bit of canola oil or very soapy water would work) but I’m inclined to think that a few adult gypsy moths are the exception rather than the rule.”

Tree Wardens Celebrate 25th Anniversary

tree wardensOn April 28, 2017, the Tree Wardens’ Association of Connecticut, Inc., celebrated the 25th anniversary of its founding with a gala event at the Omni Hotel in New Haven.

The organization was founded by Bob Ricard, Senior Extension Educator, as a result of his findings in a statewide needs assessment he conducted in 1991, the year he started working for UConn Extension. The results suggested that tree wardens (each municipality must have a tree warden based on state law passed in 1901) were not organized, received very little educational support, and didn’t know other towns had the position. Bob conducted a field workshop then the first organizational meeting at the Haddam Extension Center March 3, 1992. He was assisted by the late Dr. Dave Schroeder and Fred Borman, CT-DEEP, with the workshop.

Today the organization has around 200 members and an active board (including having recently completing a facilitate strategic plan to map out its next 25 years. Bob conducts the annual Tree Warden School (since 1998) with over 300 tree wardens, deputy tree wardens, and others passing the final exam. The organization hosts two workshops and an annual dinner meeting, advocates concerning laws pertaining to tree wardens, and sponsors tree planting events.

At the gala, Dr. Mike O’Neill, congratulated the organization for its success. Senator Blumenthal did the same and presented Bob with a Certificate of Recognition for founding and facilitation of the organization through its 25 years. At the end of the gala, attendees were talking of the next 25 years and getting together for the 50th anniversary.

Stormwise: There’s An App For That

StormwiseUndergraduate students in the Department of Computer Science are developing a Stormwise app. The app will have two functions; tree failure reporting where individuals can provide a description and photo, and the app will walk people through a hazard tree assessment process. Collecting tree failure data will be of great value for research down the road, and will help prioritize work. All data from the app will come back to UConn. The app will be marketed to the public and other stakeholder groups when it is debuted later this year. Outreach audiences include elected officials and emergency management directors that make decisions about power and transportation networks in their community. Tree crews, tree wardens, and community stakeholders are also included. The Stormwise website also offers information for various stakeholder groups, and the program has an active Twitter account.

Got Holes in Your Trees?

By Joan Allen, Assistant Extension Educator

 

woodpecker damage in tree
Woodpecker damage. Photo: Joan Allen.

It’s not generally good news if you discover holes in the bark of your trees.  Common causes of holes in trees include wood boring insects and birds.  In the case of insects, it is usually the larval stage that feeds within the tree while the adults feed on leaves or other external tissues.  In spite of this, it is most often the adult stage that created holes in the bark.  These may be either entry holes caused by adult beetles entering the tree to lay eggs or exit holes created when mature beetles or moths emerge following pupation.

Bark beetles are very small, often just a few millimeters long in the adult stage.  A typical life cycle would go as follows:  Adult beetles mate and females bore through the bark of host trees, leaving a tiny round entry hole.  Once below the bark, she excavates a parent gallery and lays eggs in niches along its length.  When the larvae hatch they tunnel outward in a pattern (gallery) characteristic of that species which can aid in identification.  They feed on the living cambium layer between the bark and the wood and when the cambium layer is killed all the way around the tree no new conductive tissue is produced for movement of water and nutrients in the tree and the tree dies.  Once the larvae mature, they pupate in their galleries and emerge as adults through new exit holes in the bark.

Bark beetles are often attracted to trees stressed or weakened by other agents such as drought stress or other pests and diseases.  In addition, some species emit an aggregation pheromone from an attractive host tree that attracts many more bark beetles of that species.  When many entry and exit holes occur together it looks like shotholes and there are certain bark beetles that are known as shothole borers.   Some bark beetles carry fungal spores on their bodies and when they create their parental/egg laying gallery, the fungal spores are introduced into the host tree where the fungus can develop in the wood.  These fungi may or may not have a direct impact on tree health and the fungus is sometimes a source of food for the larval insects.

D- shaped or oval exit holes are typical of Buprestid beetles including the emerald ash borer (D-shaped).  Common names of beetles in this group include metallic wood boring beetles or flat-headed borers.  There are over 15,000 species and some have brilliantly colored metallic looking elytra (wing covers).  Holes are relative to the size of the beetles, which are small to medium in size.  The D-shaped exit hole of the emerald ash borer is about 4-5mm across and the beetle is just under ½” long.

Round exit holes that are larger than those of the bark beetles are created by round-headed or longhorned beetles as they exit trees (family Cerambycidae).  In this family, eggs are often laid singly in the bark and newly hatched larvae tunnel into the wood to feed until they pupate and emerge as adults.  The Asian longhorned beetle falls into this group and the emergence holes are deeper than those of many other similar beetles.  Pupation of the Asian longhorned beetle occurs not far below the bark but these larvae tunnel throughout both the heartwood and sapwood of the tree.  Because of this, they tunnel out toward the bark to pupate, creating a tunnel from deeper in the tree.  There are a number of native longhorned and other beetles that created similar exit holes.  If you are concerned that you may have a tree infested by Asian longhorned beetles be sure to contact the plant diagnostic lab in your state (at your state’s land grant university of state agricultural experiment station) for a definite identification.

Some borers create somewhat longitudinal or horizontal scars on the surface of woody stems and branches.  Examples are the rhododendron borer and the sugar maple borer.  Two types of borer may attack rhododendrons.  The rhododendron borer is the larva of a clear-winged moth while the rhododendron stem borer is a longhorned beetle.  Evidence of damage begins as wilted then dying shoots and stems.

At least two types of bird create holes in the bark of trees to access food.  Woodpeckers create large, irregular and rough-edged holes as they peck away at the bark to get to insects, including borers underneath.   Sapsuckers also peck holes in trees but they are smaller, uniform in size, round and often occur in rows or grids of multiple feeding sites.  As their name implies, sapsuckers feed on tree sap, not insects.

There is a final interesting cause of holes in sugar maple. Taps used for extracting sap for maple syrup production can also create round holes in that type of tree and they look very much like the exit holes of some of the larger wood boring beetles!

EAB Quarantine Extended to All of Connecticut

EABsmallThe quarantine for the invasive, non-native emerald ash borer (EAB) was extended to include all eight Connecticut counties effective December 5, 2014. This was in response to the detection of EAB in Middlesex and New London Counties. EAB is already established in numerous towns in New Haven, Fairfield, Hartford, and Litchfield Counties. The movement of ash (ash logs, ash materials, ash nursery stock, and other regulated articles) within and between the eight counties of Connecticut are no longer subject to state or federal quarantine. However, out-of-state transport of ash and the transport of firewood of all tree species, including ash, within Connecticut continue to be regulated. Connecticut was added to the federal EAB quarantine around the same date. More information about the emerald ash borer and related quarantines can be found on these websites: DEEPConnecticut Agricultural Experiment Station.

Trees in Bushnell Park

sweet gum tree
Sweet gum looking up the trunk toward the canopy. Photo copyright 2013 Pamm Cooper

I recently went to Bushnell Park for the first time in my life and was glad I tagged along. My favorite plants since childhood are trees, especially the kinds you can climb up into and take a seat on a limb broad enough to provide a comfortable seat so you can view the world around you from a different prospective. It was while quietly sitting im trees that I first encountered many birds at close range, such as cedar waxwings, that don’t seem to mind being close to you if you are still and seem to be a part of the tree.

Bushnell Park, the oldest publicly funded park in the United States, was named for the Reverend Horace Bushnell, who conceived the idea of an open space in Hartford that would be available for people to enjoy free of charge. His good friend was the landscape architect Frederick Law Olmsted, who was involved in the designs for both Central Park in New York City and Forest Park in Massachusetts at the time but recommended Horace consult his Swiss- born counterpart, Jacob Weidenmann, who was also a botanist. Weidenmann became the first superintendent of parks in Hartford, and not only designed Bushnell Park, but also Cedar Hill Cemetery on Fairfield Avenue. Both of these parks are dotted with many notable trees, including those considered state champions.

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