El bosque del parque central de la urbanización El Paraíso: estructura, composición de especies y crecimiento de árboles
We studied an urban forest established in 1988 by residents of the El Paraíso urbanization. In 2007 the forest had 37 forest species (9 native and 28 introduced) with diameter at breast height (dbh) = 4 cm in a 1.0785 ha area. The most common species was the hybrid mahogany (Swietenia macrophylla x mahagony) with an Importance Value of 24.3 percent. The forest had two species endemic to Puerto Rico (maga or Thespesia grandiflora and the royal palm or Roystonea borinquena) as well as native primary forest species such as bulletwood or ausubo (Manilkara bidentata) and lignum vitae or guayacán (Guaiacum officinale) and native pioneer species such as pumpwood or female yagrumo (Cecropia schreberiana), among others. Pumpwood was the only species that propagated naturally after an adult tree planted by residents flowered. The forest’s basal area was 17.3 m2/ha and the tree density was 127/ha. Because many of the trees were multi-stemed density was 215/ha. The forest was distinguished by an absence of natural understory, little accumulation of litterfall, trees with mean dbh and height of 26.8 m and 9.8 m respectively, and rapid growth in the majority of the trees. Approximately half of the trees did not grow or grew very slowly with the remainder growing at rates greater than 20 cm2/year, including 15 percent that grew at rates greater than 100 cm2/year. Annual tree mortality was 1.4 to 1.5 percent. This forest’s trees have grown at elevated rates and have developed a high and closed canopy in spite of the intensive use that the area receives. However, human activity impedes forest regeneration, which suggests that its regeneration and species composition are dependent upon the planting and care of the trees by the residents.