Environmental and Nutritional Factors Influencing Maple Tree Sap Flow

In 2014, Canada produced 80% of the world’s maple syrup supply, with Quebec contributing to 90.5% of Canadian production. The remaining 9.5% of the supply came primarily from Ontario, New Brunswick and Nova Scotia, of which NS contributed approximately 1%. While the number of taps have increased over years, the average yield per tap has declined. With a farm gate value of over $1.6 million in NS alone the industry is an importation part of Nova Scotia’s economy. This study examined the tree nutritional health and impact of certain environmental factors. Experimental sites were established in ten production areas of NS. Measurements of canopy density, leaf nutrition, core nutrition, trunk circumference, soil moisture, and soil nutrition were taken each month beginning June 2015. Maple sap was collected in spring of 2016, and evaluated for yield, nutrition, and sugar content. All sites under this study had acidic soils, with the P, K and Fe being the only soil nutrients to significantly change over the months tested. Ca, Zn and Mn were found to be significantly different between sites in core tissues, with N and Fe showing significant changes over time. Leaf canopies showed differences amongst the sites as well as over time, with densities and concentration of foliar nutrients. N, K and P decreased from June to October at all sites in the leaf tissue, with an in increase in Ca, Mg, B and Mn. Correlations were found between the soil and leaf Ca, K, Mn, P, Fe, Mg and Zn concentration. All explanatory variables were considered in developing a model to optimize sap yield and sugar content.

Keywords: Maple, sap, yield, foliar nutrients, soil nutrients, canopy, core tissue