Effect of organic and mineral mulches on soil properties and growth of Fairview Flame® red maple trees

Abstract

Five mineral mulches (crushed red brick, pea gravel, lava rock, carmel rock, and river rock) and 3 organic mulches (finely screened pine bark, pine wood chips, and shredded hardwood bark) were evaluated over 2 years to determine their influence on soil temperature, moisture, and pH, and to quantify their effect on growth of Fairview Flame® red maple (Acer rubrum L.). Soil temperature were highest and moisture percentages lowest under the mineral mulches and nonmulched control. Soil pH readings were highest under shredded bark and wood chips, and lowest in the nonmulched control. Trees growing in river rock, crushed brick, pea gravel, and carmel rock had larger stem calipers than those growing in shredded bark plots. Crushed brick, pea gravel, and carmel rock treatments also resulted in greater leaf dry mass than did shredded bark. These results, however, should not be interpreted as an indictment of organic mulches. Because stem caliper and leaf dry mass measurements of trees growing in wood chips and any of the mineral mulches were not statistically different, blanket statements and generalizations regarding the performance of woody plants mulched with organic or mineral (rock) materials are unwise.