Soil Compaction Effects on the Establishment of Three
Tropical Tree Species
Rebecca Tirado-Corbalá and Brian K. Slater
Abstract: Tree seedlings planted in containers along sidewalks in urban environments show restricted growth and development over time. This is the result of limited soil volume and soil compaction that hampers nutrient availability and water movement. Using tree species commonly used in urban forestry in Puerto Rico, this study was conducted to determine their growth response when planted in compacted soils. Seedlings of three ornamental tropical tree species, trumpet bush [Tecoma stans (L.) Juss. ex Kunth], bottle brush [Callistemon citrinus (Curtis) Skeels], and pink trumpet (Tabebuia rosea dc.) were transplanted into pots of sandy clay loam or clay soils at three levels of compaction: control (no compaction), 1.2 g/cm3 and 1.4 g/cm3 bulk density, respectively. Plant height, shoot diameter, leaf number and color, foliar area, and root, shoot, and leaf dry weights were measured on two plants every two months for six months. All species exhibited better growth in sandy clay loam at 1.2 g/cm3; after six months, all species showed a reduced root-shoot ratio. When planted in clay at 1.4 g/cm3, all trumpet bush seedlings died within two months. No leaf color differences were observed between species at different compaction levels. Bottle brush showed less growth suppression by increasing compaction level in both soils.
Keywords: Callistemon citrinus; Root Growth; Root-Shoot Ratio; Tabebuia rosea; Tecoma stans; Tree Establishment; Urban Forestry; Urban Soils