Restoring soil and tree nutrition through non‐industrial wood ash additions to sugarbushes

Nutrient losses from forest soils caused by decades of acid deposition have affected tree growth and depleted soils of essential nutrients in eastern North America. Non‐industrial wood ash (NIWA) is rich in macronutrients and may be a potential remediation strategy to restore lost nutrients as a forest soil amendment. We evaluated the effects of a single NIWA application on forest soils and Sugar maple ( Acer saccharum Marsh) foliage at three sugar bush stands in Muskoka, Ontario, Canada. Soil pH and calcium (Ca) increased in the treatment plots (4 and 8 Mg/ha) 1 year after application and remained elevated into year 2. Soil potassium and magnesium concentrations also increased in the treatment plots; however, changes varied in intensity depending on the element, site, and time following application. Changes in soil metal concentrations after application were restricted to the organic soil horizons increasing in the litter in year 1 followed by a decrease in year 2 that was accompanied by increases in the fibrous‐humic layer in year 2. Base cation concentrations increased significantly in sapling and mature sugar maple foliage particularly in the mature foliage in year 2. Despite changes in soil metals, changes in foliar metal concentrations were generally not significant. Foliar Diagnosis and Recommendation Integrated System indices indicated deficiencies in Ca and nitrogen (N) suggesting Ca benefits take longer to appear and that supplementing with N additions on acidic soils exhibiting foliar deficiencies might prevent further imbalances from occurring while facilitating tree recovery.