Healthy Forests Healthy Rivers 

Riparian Diversity in a Post-Emerald Ash Borer Landscape

You can imagine the calls and questions we receive at Kretz Lumber pertaining to the Emerald Ash Borer (EAB). With almost certain mortality for our state’s ash trees, how will our forests change? Will all ash become Ash-au-gratin? What species will take its place? What areas will be affected most? Is there anything we can do as landowners to curb the impact? The word is out that this emerald green insect’s favorite (and only) snack is our beloved ash tree. The borer can even munch on ash trees less than 1” in diameter. The WI DNR’s models based on field observations predict that a healthy forest will lose 98% of its ash trees in six years. If we have been doing our jobs as foresters and landowners, our forests will be diverse enough to handle the impact of losing another species, but certainly will never be the same.

Capturing the value of these ash trees is important; we are doing our best to stay ahead of the insect and harvest ash while we can still utilize the lumber, before it becomes “bark biscotti”. EAB galleries tend to stay near the surface of the wood in the nutrient-rich phloem, which means we could still salvage some lumber from that log, right? The problem is, other insects move into these infected ash trees as well. These insects include ash cambium miner, banded ash borer, redheaded ash borer, privet borer, banded ash clearwing moth, carpenter worm, and many others. These insects can make their way to the heartwood and ruin the entirety of the log. Time is of the essence to salvage our ash trees.  

Particular forest types that I am worried about are swamp hardwood stands near trout streams, ephemeral ponds, or otherwise “springy” areas. Conserving such a resource is one of the many goals we help landowners achieve. Whereas white ash and green ash tend to be on higher, drier ground, black ash is a riparian species best suited for lower, wetter ground. These areas can be very difficult to freeze down and near impossible to access with logging equipment.  It may be difficult to pre-salvage black ash before the Emerald Ash Borer calls it baby “bark” ribs! So, if you own land on a trout stream and have a fair amount of black ash, should you be worried? 

After speaking with multiple DNR Fishery Management Specialists, it seems that some landowners should be concerned. The general consensus amongst the specialists who I spoke with is that trout streams in our northern counties including Lincoln, Langlade, Forest, Oneida, and northern Marathon counties are at lower risk to rising water temps due to EAB. The trout streams in these counties are primarily fed by groundwater. These streams may not be affected as much as our southern counties, which tend to rely more upon runoff than groundwater recharge. DNR Fishery Management Specialists have seen the effects first hand in our southern counties that have been hit by EAB.

With the massive die-off of ash, some stream banks have lost definition and will ultimately become wider, shallower, slower, and therefore warmer. Stream banks that are now heavily stocked with ash trees may be overtaken by reed canary grass and tag alders. While the root masses of reed canary grass and tag alders can often hold the bank’s definition, they do not provide the shade or root mass that a diverse forest could. Keeping a stream shaded and cool is important, as brook trout can only thrive in water temperatures between 45 and 65 degrees. A healthy, diverse forest along a stream can slow the descent of precipitation and prevent erosion. Although our focus is on trout streams, every landowner affects the watershed. Many woods we work in have water holes at bottoms of slopes, which we call ephemeral ponds. These areas store water for the time being, while it is being filtered and moved underground. The ground acts like a refrigerator, cooling off the water and discharging it to wetlands and spring holes. 

If a landowner has the time and money to do so, planting trees along streams, ephemeral ponds, or “springy” areas is a great idea to curb the impact that EAB may have on their respective watershed. There are many private nurseries that sell tree seedlings every spring, but the Griffith State Nursery does a great job providing healthy seedlings. I just picked up my order last week and was impressed with the size of the black spruce I ordered. Black Spruce, Red Maple, Tamarack, Hemlock (my favorite tree), White Cedar, White Pine, and Swamp White Oak would all be great options to plant in a riparian setting. Do not forget about shrubs though, Buttonbush, Dogwood, and Ninebark Hickory could also do well and provide great cover for wildlife. Make sure you get your order in early, Griffith starts accepting orders in October for the following spring. Planting trees is a great way to get your family involved with your property, help your watershed, and to carry on the legacy you are creating as a landowner. Find more information about ordering trees from Griffith State Nursery here.

Call your Kretz Forester or contact us online if you need help deciding which species are best suited for your property.