Assessing threat against trees, preventing future fire danger

by Peter Jakey–Managing Editor

It’s been almost two months since a generational ice storm that has left northern Michigan residents still cleaning up the debris left by tree limbs snapped from trunks and/or entire trees toppled over from the sheer weight.

In the storm’s wake, there are a number of concerns that remain, including insect damage and disease or the threat of fires from branches not cleaned off the forest floor or will continue to dangle precariously.

According to Jacob Grochowski, district forester for Presque Isle and Cheboygan counties, there is no hard data available to confirm which trees took the most damage.

“But, it appeared to me that plantation red pine, white pines, and soft-wooded species like aspen, poplar, and willow were most consistently and severely damaged,” said Grochowski, who is employed by the Presque Isle Conservation District (PICD).  

With that, the ice storm has left unnumbered wounds on trees throughout the tip of the mitt and that has left an opportunity for additional pests and disease.

“While wounds are fresh, they release compounds that some insects can detect, which can attract those insects to the damaged tree,” said Grochowski. “The beetles that spread the oak wilt fungus, called Nitidulid or picnic beetles, are drawn to fresh wounds on oak trees. Those beetles may be flying to that fresh wound after being in contact with the spores of the oak wilt fungus Bretziella fagacearum and inadvertently spreading oak wilt to the newly wounded tree.”

Currently, northern Michigan is in the highest-risk period for oak wilt infection that extends into mid-July, and while branches broken off during the storm will be too old for infection, new pruning cuts or those widowmakers hanging from higher in the trees’ crowns could provide a steady stream of fresh wounds for oak wilt to infect this summer. 

“Typically, tree wound paint is not recommended on pruning cuts, but due to the high risk posed by oak wilt, all new pruning cuts and removals of widowmakers should be followed by sealing the wound with a latex-based tree wound paint,” said Grochowski.

Regarding the fire danger, downed trees and branches provide additional fuel that creates the risk of harder-to-control wildfires.

“The risk posed by the fuels will increase as they dry out and cure, which happens more rapidly when fuels are suspended above the surface of the ground,” Grochowski continued.

Fortunately, the area affected by the ice storm is not currently in drought conditions, according to the National Drought Monitor. 

For those living in forested areas, consider visiting the Firewise USA website (www.firewise.org) to learn about minimizing the risk posed by fires by managing the vegetation and materials in your home ignition zone. 

PICD also has Firewise materials available at their office in the Presque Isle County Courthouse building. 

“By following these guidelines you can lower the risk to your home and improve the ability of firefighters to defend your property in the case of a fire,” said Grochowski. 

The process of recovery will vary across the landscape according to the level of damage and the species of trees involved,” said Grochowski. 

“In some areas, such as red pine plantations with lots of fresh pine debris on the ground, bark beetle outbreaks may cause additional standing pine trees to die,” he said. “Trees established in the shade of the red pines, often hardwoods like red maple and oak, will start growing more quickly in response to the additional light now reaching them. 

“Most deciduous trees will sprout new twigs from buds underneath their bark, likely leading to a bushy appearance in the first year of growth, which will keep the trees alive but also reduce their long-term branch strength and their value as timber (for some species).”

New growth will be abundant in many areas, that will provide a great deal of food and habitat to many wildlife species. 

“Trees with a severe lean are harder to predict,” said Grochowski. “For some, the damage to their roots and attacks by pests will lead them to die rapidly. 

“For others, they may re-establish strong roots and continue growing while leaning– this is probably most commonly seen in white-cedars in a forested setting. Others may continue living until another storm fully uproots them or causes their trunk to break.”