Vice-Chairman, Friends of the Muskoka Watershed
Vice-Chairman, Friends of the Muskoka Watershed
Recent research co-authored by our Trent University collaborator, Dr. Shaun Watmaugh and led by his M.Sc. student, Holly Deighton**, has definitively shown that dosage levels of 6 tonnes per hectare of wood ash addition to forest soil resulted in significant increases in soil pH and calcium and magnesium concentrations. The level of response, however, varied by treatment. Foliar concentrations of base cations in sugar maple seedlings significantly increased in ash treatments and there was no significant treatment effect on foliar metal concentrations or seedling growth. In roots and shoots, concentrations of several metals (manganese, aluminum, iron, boron, arsenic, cadmium, zinc, copper, lead, chromium, and nickel) increased after ash application, however response was most pronounced in yellow birch ash.
These results suggest that application of non-industrial wood ash can counteract the lasting effects of acid rain by increasing soil pH and base cation concentrations, as well as increasing sugar maple seedling foliar nutrient concentrations, but ashes from species with high metal contents may also increase metal availability to vegetation, at least in the short‐term.
The research cited suggests we should see real benefits from our ash additions, both the one completed in the fall of 2019 and the upcoming larger-scale addition in 2021. With such positive results after only 3 months, it means we are on the right track in the revitalization of our local forests which have been impacted by acid rain. It also means that proceeding with our larger-scale deployment will not be problematic with respect to levels of metals concentrations in the ash as they do not exceed provincial regulations. Given the conclusions of this early research, we anticipate extremely positive results with our larger-scale deployment of between 6 and 8 tonnes per hectare, results which may not only “wake up” the currently napping forests but also increase transpiration rates and have a positive impact on the ability of the forest to mitigate the effects of increasing levels of precipitation in the region.
**Holly D. Deighton and Shaun A. Watmough, Effects of Non‐Industrial Wood Ash (NIWA) Applications on Soil Chemistry and Sugar Maple (Acer saccharum, Marsh.) Seedling Growth in an Acidic Sugar Bush in Central Ontario in Forests 2020, 11, 693; doi:10.3390/f11060693
FMW’s approach to protecting Muskoka watersheds is to work with the local and scientific communities to identify, develop and foster solutions to the stressors in our watershed. The proposed solutions may be novel, such as the use of non-industrial wood ash to solve the widespread calcium decline problem. New approaches are risky. They may not work. This issue’s Graph of the Month provides the first proof that the risk was worth taking, i.e. local firewood ashes do provide a rapid and substantial benefit to local sugar maple.
The accompanying chart highlights one key result of Holly Deighton’s Masters thesis research directed by Dr Shaun Watmough at Trent University, and FMW partner. With FMW support, Holly added ashes from maple, yellow birch and pine firewood to small 2*2 m plots supporting maple seedlings in a local sugar bush. All three ash types reduced the acidity and increased calcium and magnesium levels in the soil. The chart shows this led to dramatic increases in calcium levels in all parts of the maple seedlings. Holly’s work was a small pilot study in the ASHMuskoka project, but it provides our first proof of principle that local residential wood ashes can provide the solution to ecological osteoporosis in Muskoka forests.
It takes knowledge and will to solve ecological problems. For the ecological osteoporosis problem, we are beginning to develop the knowledge. The next step is to refine the needed doses and prove additions work at a larger scale in multiple locations. That’s why we are following the results of last November’s larger ash additions in three sugar bushes. This should teach us what we need to know for our watershed-scale ash addition over the next 12 months.
Please keep “saving your ash” for us. We will be continuing to collect it from you over the coming months.
It’s been a long time since our last ash drive for our ASHMuskoka Program – 6 months, in fact. We are sincerely grateful for your patience during this time and for continuing to save your ash in order to help restore vital calcium levels in our Muskoka forests and lakes.
We are announcing today that ash drives will be resuming beginning August 15th with a total of 7 currently scheduled for the remainder of 2020. They will take place at the Rosewarne Transfer Station in Bracebridge from 9am to 3pm on the following Saturdays:
We are holding 2 ash drives in each of August and September as many of you have informed us that you have large quantities of ash saved. We want to make it as convenient as we can at this point for you to drop off the ash to us.
As we do for each ash drive, we again ask that you indicate whether you will be able to drop off your saved ash by clicking on the link button above and filling in the form on the page. Note that this does not restrict you to only one ash drive. It simply helps us to effectively plan each date for the benefit of our ash contributors.
Wood ash is not particularly soluble in water, but it’s not quite that simple.
Solubility in water is simply a measure of how much of a solid can be dissolved in water under specified conditions. It’s complicated for wood ashes because ash isn’t a simple solid. It has a quite course charcoal-like component – the product of incomplete combustion of the wood, and this component isn’t very soluble at all. It just floats on water. The grey powdery component of the ashes is also a mixture of minerals. It’s about 9% potassium (K) minerals, for example, and these are very soluble in water. There is also a small component of phosphorus (P), and it is quite insoluble, likely a good thing as excess supply of P to watersheds could have unintended consequences. But what we care most about is the roughly 30% of the ash formed of minerals of calcium (Ca), mainly calcium carbonate. Calcium carbonate is somewhat soluble in water, much less than the potassium component and much more than the phosphorus competent, again likely a good thing. With every rain, a little more of the Ca in the ash will dissolve and percolate into the soil. Because of this modest water solubility, wood ashes should provide a long-term source of the missing Ca in soils, the long-term goal of ASHMuskoka.
Wood ashes are very alkaline, with pH levels of around 9 to 11. But what is pH and what pH is too acid or too alkaline to safely handle or for ecosystem health? The “p” in pH stand for “power”, as in “raised to the power of” in mathematical notation, and the “H” stands for hydrogen. Technically pH is a measure of the strength of an acid solution, i.e. a solution of H ions. It is calculated as -log10H. Complicated, but here’s what it means. It has a negative sign, implying the lower the number the stronger the acidity, so water with a pH of 4 is much more acidic that water with a pH of 5. It’s also a log-scale, meaning a unit change represents a ten-fold change. So pH 4 is actually 10 times more acid than pH 5, and 100 times more acidic than pH 6. A pH of 7 is deemed “neutral”, neither acidic nor alkaline.
pH is a log scale. So pH 4 is actually 10 times more acid than pH 5, and 100 times more acidic than pH 6.
We are exposed to solutions of many different pH levels in our every day lives. Battery acid has a pH of 1 – take care! In the kitchen, vinegar, soda drinks, and lemon juice are quite acidic with pH levels of 2 to 3. Milk is almost neutral with a pH just under 7. Meat has a pH of 5 to 7. Baking soda in solution is alkaline with a pH of about 8.5. Among the most alkaline products in our home are cleaning agents such as Javex (pH 11), and TSP (pH of 12-14), and we know to take care when using them. Wood ashes are almost as alkaline when dissolved in water, with a pH varying from about 9 to 11. Thus adding wood ash to our soils has two distinct benefits. It is alkaline so it can neutralize soil acidity, and the source of the alkalinity is calcium minerals, so it can replenish the Ca lost to decades of acid rain.
If you are interested, here is an interesting interactive demonstration on pH values from the University of Colorado Boulder. Click or tap on the Macro view and select various liquids from the drop-down menu at the top. More can be added by pushing the red button on the dropper. Dragging the green ‘sensor’ to the liquid will give you the pH reading on the scale. Try adding water via the tap to see how it affects the pH value.
Our lakes get calcium (Ca) naturally from the air and from surrounding lands, and on occasion, from us. Ca enters lakes directly from the atmosphere, in the form of windblown dust and precipitation, but as measured by MECP  scientists, these inputs have actually fallen by about 50% in Muskoka over the last few decades as we have reduced air pollution levels.
Secondly, Ca enters our lakes in overland flow in streams in the watershed. The rate of this calcium supply is controlled by both rates of stream flow and the Ca concentrations in stream waters, the product of which is the total Ca supply. This overland supply has fallen because both stream flow and Ca concentrations have fallen, the former likely linked to climate change, and the latter, a legacy of acid rain. This leaves us. We add Ca to our watersheds and the lakes they support in many ways, mainly inadvertently. We bring soil and fertilizer to our gardens and lawns. We clear the land, potentially mobilizing stored Ca. We add calcium chloride as a dust suppressant to our gravel roads. One such dust-controlling trip a year for several years reversed the Ca decline trend in Dickie Lake, east of Baysville.
Finally, we can add ashes from our fireplaces to our forests. If the wood came from our property we are recycling Ca from our land. If we brought the fire wood in from elsewhere, then spreading the ashes on our property can start the process of reversing decades of Ca loss. This is one of the goals of our ASHMuskoka project.
 Ontario Ministry of the Environment, Conservation and Parks