Woodlot Health Issues
Another Woodlot Threat Coming Our Way
Oak Wilt — fungal pathogen (Ceratocystis fagacearum)
Oak Wilt results from a fungal infection that creates fungus colonies under the bark of oak trees that prevent nutrient flow. Once infected, the tree usually dies within a year. At this point, it appears that all oaks are vulnerable, but so far does not extend to other tree species.
You first notice the problem when the tree begins to "brown" beginning at the top, and individual leaves take on an appearance as shown here. Closer inspection will identify bark sections that have cracked and raised due to a fungus mat just below the surface. Progression varies from tree to tree, but the end result will be the same.
To this point in time, there have been no confirmed cases of Oak Wilt in Canada. However, more than 100 oak trees have been lost on Belle Isle in the Detroit River — a mere 600 metres from Windsor. To date, more than a half million oaks have been lost in Michigan State Parks alone. There are numerous infected pockets on the west side of Lake Huron ... about 150 km from our shore. It is not impossible for the fungus spores (or the transporting insects) to get caught up in a weather incident and travel across the lake to our doorstep.
The fungus spreads in 2 ways. Firstly, sap and bark feeding beetles are attracted to ailing or damaged trees and, as they feed, they pick up the fungus spores and then transport them to their next tree. The most active time for this are the months of April through August. Secondly, the fungus can transport systemically and will spread through the tree's root structure to neighbouring oaks. Oaks are known to have interconnected root systems.
There is no practical cure or treatment for this disease, however some areas are working with fungicides but cost and physical danger discourage this. Prevention is the only course of action. Do not prune, cut or damage the tree during the vulnerable months. If such happens, fully paint open wounds with a wound or latex paint. This will prevent or discourage the sap beetle activity. Remove dead/infected trees. Chipping, splitting, debarking, burning or burying works. DO NOT transport the wood, as fungal spores can survive in the dead wood for more than a year, and you do not want to move it into a clean area.
For more information, go to the Oak Wilt Fact Sheet.
New Woodlot Threat
Dog Strangling Vine — Black Swallowwort and Pale Swallowwort
In the mid-1800's, these two look-alike members of the milkweed family were introduced to the northeastern United States for use in gardens. Recent years have seen the species propagate rapidly and now pose a major threat to areas in southern and central Ontario, as well as the northeastern United States.
The plants form large communities and collectively over-run and choke out native vegetation along fence lines, stream banks, roadsides and wooded areas. Due to their similarity to milkweed, the Monarch Butterfly will lay their eggs on the plant, but these eggs will not survive — thus having a highly negative effect on the Monarch population.
The local hot spot is the Thames River Valley in and around St. Marys which means that it will soon (if not already) be in our woodlot. It is spread easily by the wind, but more significantly by human contact -- such as attaching to boots, clothing, ATV's etc. It also sends up new shoots from roots and damaged areas. Although chemicals such as Roundup are fairly effective, the plants locations do cause control challenges.
For more information, download the Dog Strangling Vine Factsheet.(2 pages — 681 kbytes)
Emerald Ash Borer — Where Are We Now?|
|"The invasion of the Emerald Ash Borer is an environmental disaster with an impact of the magnitude of Hurricane Sandy — and potentially of the sum-total of all hurricanes of the past 5 years."
|| Statement made at a 2013 EAB Community Information Presentation.|
EAB Beetle Facts
In 2002, the invasive Emerald Ash Borer beetle was identified in the Windsor/Southeast Michigan region. It probably had been present for a few years prior to that. Originating in Asia, the destructive pest was most likely transported to North America via infested shipping materials. To date, it has claimed in excess of 100 million ash trees. Although the beetle has a maximum natural spread rate of about 15 kilometres per year, it has now migrated to more than 20 US states (mainly in the northeast) and 2 Canadian provinces — in just 12 years. Distribution to new territories has been mainly via the movement of firewood by unsuspecting individuals.
Authorities have now declared all infested regions quarantined as to Ash wood transport — with fines of up to $250,000 for violators. In 2012, one individual was fined $10,000 for ignoring a 10 m square road sign for the sake of a half cord of firewood in his pickup truck. This is serious business.
The Emerald Ash Borer has a normal life cycle of 1 year. The adult beetle emerges in late May and flies into the crown of the ash tree where it feeds on the leaves for a short number of weeks. The leaf damage of this phase is minimal. During this time the female will lay from 70 to 250 eggs in the rough furls of the bark. The adult beetle soon dies. The eggs hatch in about 2 weeks and the tiny larvae then burrow into the bark and begin feeding. Over the next few months, they feed voraciously in the tender cambium layer, leaving serpentine trails between the bark and sapwood. With several hundred (or thousand) of these larvae feeding, this process in effect girdles the tree and prevents the nutrient flow between roots and leaves. The tree soon dies. The larvae winters under the bark, and in the spring goes through 4 pupae stages as it changes form into the beetle. In late May, the adult beetle exits the tree leaving behind the classic "D" shaped hole. The cycle repeats. As a note here, it appears that trees less than 2.5 cm in diameter seem not to be affected — probably because their bark is smooth and unsuitable for egg deposit. However, as they grow, they too will become infected and then be lost. It is unlikely that any ash will survive for the future.
Based on the experiences of other communities, it appears to be about 5 years from the first detection of the beetle to the die-off of the majority of ash trees in the area. We have been watching the progression of the infestation as it marches toward us. Although we have observed distress in some of our trees and the deaths of a few, the peak of the infestation has yet to be realized. Yes, the borer is in the woodlot, and it is expected to be much more noticeable by the end of this summer. Next summer, we expect to see the collapse of our ash population where large numbers fail in a short period.
Previous Similar Issues
In the early 1960's, the Dutch Elm Disease killed the majority of the majestic Elm trees in Southern Ontario. Since such die-off was a new experience, there was no response plan for this problem. Most areas just stood and watched as the stately trees died — and then began dropping large branches on the unsuspecting below. Authorities reacted by then attempting to cut down the couple-of-years-dead trees, only to find that many of the woodcutters suffered serious or fatal injuries in the process. As a result, the dead elms became known as "Widow Makers", for obvious reasons. Major lessons were learned for future responses to large scale tree die-off situations.
In the early 2000's the Sawyer Woodlot faced the sudden die-off of most of our Bitternut Hickory trees due to an infestation of the Hickory Bark Beetle. A significant part of Southwestern Ontario was impacted. Having learned from the Dutch Elm situation that doing nothing was not a viable solution, we chose to remove a few trees as logs and the remainder as firewood. The suddenness of the die-off and the rapid deterioration of the wood resulted in our response being a bit tardy as the few logs removed were of marginal quality. Volunteer woodcutters were able to bring down all major dead trees safely — but it was a very risky operation. The lesson learned was that the reaction to such a situation in the future must be quicker and more decisive.
Our Emerald Ash Borer Response
As of 2010, it has been estimated that the Sawyer Woodlot contained 10,000 ash trees. Of that number, at least half of them were of a diameter smaller than your wrist. The majority of those would be lost due to natural attrition. Of the remainder, about 1000 were larger significant specimens at or approaching maturity. The balance were of various lesser sizes — perhaps described as the "tweens, teens & youths" of the woodlot.
When developing our strategy regarding the approaching EAB crisis, the following considerations were front and centre:
- What was learned from previous die-offs i.e. Dutch Elm Disease, Hickory Bark Beetle
- Time-line for impending die-off
- Effects of various possible responses
- Safety of woodlot visitors and association members
- Impact on wildlife
- Impact on remaining trees and vegetation
- Overall woodlot health
- Resources available
- How are other jurisdictions responding
- What would Otis do?
The first strategic decision was easy — doing nothing was not an option. To do so would mean closing the woodlot to all visitors for probably 5 years, or perhaps longer.
The second strategic decision was almost as easy — the significant ash trees in the human traffic areas must be cut down before they are dead (or as soon as they die) for safety reasons. Those in remote areas could be allowed to die and fall naturally for the benefit of wildlife.
Subsequent decisions were not as easy. Do you log; simply cut and drop; remove wood of value; chip & mulch; or somewhere in the middle? Resources are limited — both human and financial. Which route is of the greatest benefit to the woodlot itself? What are we reasonably able to achieve?
In 2012, about 200 trees were removed as logs and firewood in anticipation of the Emerald Ash Borer infestation, as well as for general woodlot thinning. In 2014, a further 161 ash trees were removed for logs while they had some market value. All of those removed were expected to die within 2-3 years due to EAB, and to soon become liability issues. Even with this culling, there remain several hundred ash trees that will have to be handled in the near future. They will die and they will fall down. With the significant human traffic in the woodlot, that is a concern.
The Board of Directors is closely monitoring the situation and will take down those dead and dying trees that pose a threat to woodlot traffic. Cleanup will be ongoing but will probably fall short of leaving a pretty scene. However, wildlife does not appreciate the human definition of "pretty". Wild turkeys and other critters have already set up housekeeping in our less than pretty brush piles. To them it is paradise.
Safety is our top priority and our continuing response will support that. We will attempt to stay ahead of the situation and not make the mistakes of the Dutch Elm era. Hopefully, the woodlot can remain open to visitors. EAB has been an unwelcomed diversion from the hopes and wishes of our association. However, EAB is reality. It is a daunting challenge, but we are dealing with it. We are moving forward. We are doing the best we can. AND the sun will rise tomorrow.
More Information from: Ontario MNR Michigan State University Canadian Food Inspection Agency
Giant Hogweed ... ALERT
As you explore our woodlot, please be on the lookout for this nasty non-native invasive plant. The most likely location would be along the stream and in wet areas. Although its presence has not been detected within our boundaries, there have been scattered reports of it across Southern Ontario. If you should detect one on or near our property, please let us know its location A.S.A.P.
Giant Hogweed is an invasive, non-native plant that poses a serious threat to human health and natural ecosystems.
The clear sap found in the hairs, leaves and stem of the Giant Hogweed plant contains compounds that cause photodermatitis (symptoms can range from redness and itching to painful blistering). Contact with the eyes can cause temporary or even permanent blindness in some cases.
If you are exposed to Giant Hogweed:
* Wash the affected area thoroughly
* Avoid exposure to sunlight
* Seek medical attention
Key Identifying Features:
Height: 1 to 5.5 meters
Leaves: large, deeply cut with sharp coarse teeth, reaching widths in excess of 1 meter.
Stems: hollow, ridged with red-purple splotching and coarse white hairs, with a diameter of 4-10 cm at its base.
Flowers: white, compound umbel (80 or more cm across) made up of 4 to 12 smaller (14 - 40 cm) flat, round units.
Credits: Town of Markham
This is a nasty plant with much more serious medical consequences than poison ivy. Do NOT touch it! If you think that you have found a specimen, note carefully its location and then report immediately.
Click for more information:
Ministry of Agriculture, Food & Rural Affairs
USDA Brochure on Giant Hogweed.
The Bitternut Hickory population in the woodlot is currently experiencing a major attack from the Hickory Bark Beetle. The result to date has been the deaths of a significant quantity of specimens with many more now in distress. During the spring of 2006, approximately 50 trees were removed. 2007 & 2008 saw even greater numbers cut down. This culling is expected to continue for the next few years. Before it is all over, we expect to lose about 90% of the Bitternut Hickory in the woodlot. Although somewhat disappointing to the association, this is all part of the nature's way. The Bark Beetle is a native species and these infestation cycles appear from time to time. At the moment, a large portion of Bitternut Hickory trees in Southern Ontario are threatened. But all is not bleak. In times of severe stress, the tree is known to react by sending up new growth from the stump — with each generation being more hardy than the previous. We can now watch to see if that will be the case this time. In the meantime, we have a supply of very high quality firewood.
|Egg and larval|
galleries under bark
From Ontario MNR (2 pages — 2296 kbytes)
From Bugwood Network
Garlic mustard poses a severe threat to native plants and animals in forest communities in much of the eastern & midwestern U.S. as well as Southern Ontario. Many native widlflowers that complete their life cycles in the springtime occur in the same habitat as garlic mustard. Once introduced to an area, garlic mustard outcompetes native plants by aggressively monopolizing light, moisture, nutrients, soil and space. Wildlife species that depend on these early plants for their foliage, pollen, nectar, fruits, seeds and roots, are deprived of these essential food sources when garlic mustard replaces them.
The association has been active in an attempt to control this invading species in recent years. It is an ongoing effort requiring considerable manpower and persistence. The control program is having success but must continue for some years to come.
More Information: From Lake Huron Centre For Coastal Preservation
From Province of Ontario
Asian Long-Horned Beetle
The Asian Longhorned Beetle (Anoplophora glabripennis) is a potentially serious threat to some of North America's most beautiful and popular trees. It is native to China and believed to have arrived in packing crates. Infestations have been identified in New York, Chicago and Toronto. In all cases of infestation, the affected trees are cut down and the wood destroyed. The primary victim to date has been the maple — but also willow, horsechestnut, poplar and elm. At the moment it is not an imminent threat to the woodlot — but the situation is being monitored.
More information: From Ontario MNR
From Canadian Food Inspection Agency
The Common Buckthorn (Rhammus cathartica), an exotic invasive species, was brought to America in the mid-1800's as hedging material. With no natural controls, it tended to develop dense thickets thus crowding out native species and preventing seed germination and growth of native trees and shrubs. Buckthorn also leafs out early and retain its leaves late in the growing season — seriously impacting other vegitation. It is also known to harbour Crown Rust — a problem for oat growers. The seeds are attractive to birds and thus accounts for the extensive spreading of the shrub.
A related shrub, the Glossy Buckthorn, is also an exotic invasive species causing similar concerns. There are, however, several native buckthorns that exist and are used in the landscaping industry but do not have the invasive characteristics. We are experiencing perimeter concerns with Buckthorn and are assessing if or how we will respond. Effective control is through herbicide use and/or physical removal, but residual seeds and roots will quickly regenerate the area if control efforts do not continue.
Buckthorn Fact Sheet — Minnesota Department of Agriculture (4 pages — 159 kbytes)
Weed Of The Week — USDA Forest Service (1 page — 157 kbytes)