Changes in the physical, chemical, and hydrologic properties of pine bark over twelve months of aging

Pine bark is one of the most commonly used organic horticultural substrate components in the southeastern USA, but it can also be one of the most variable. It may be used fresh, aged, or composted, and aging and composting times may vary between suppliers or even for the same supplier at different times of the year (Jackson, 2014). Aging refers to the stockpiling and weathering of bark in windrows prior to its use, with no fertilizer additions or pH adjustments, and no attempt to control the moisture content (Pokorny, 1979). While aging is most commonly used in the southeastern USA, interest in fresh pine bark has increased because of its lighter weight, which reduces transportation costs (Fields et al., 2012).