Dwarf Forest Recovery after Disturbances in the Luquillo Mountains of Puerto Rico

Peter L. Weaver
2008 Caribbean Journal of Science  
Dwarf forest in Puerto Rico's Luquillo Mountains varies according to substrate and topography with very short, dense forest growing on exposed, rocky sites. High elevation level sites suffered considerable damage during past hurricanes whereas the trees on certain lower slopes were protected by ridges or spurs. Post-disturbance recovery of dwarf forest on two types of sample plots near East Peak was slow. Nearly 37 years after a 1968 airplane crash, Cyathea bryophila (R. Tryon) Proctor and
more » ... ia borinquensis Britton accounted for 71% of the 25.3 t ha −1 total aboveground dry weight biomass (hereafter biomass) on 780 m 2 of the crash site. This is only 30% of the 80 t ha −1 average biomass of the surrounding dwarf forest prior to Hurricane Hugo of 1989. Also, six 250 m 2 permanent plots (stratified by topography with sites on ridges, slopes, and ravines) showed delayed post-hurricane mortality, declining in mean stem numbers from 2,956 stems ha −1 in 1990 to 2,268 stems ha −1 in 2005. Average plot biomass decreased from 72.8 t ha −1 in 1990 to 61.6 t ha −1 in 2000, increasing slightly to 62.9 t ha −1 in 2005. Recovery on all sites was characterized by an immediate invasion of grass cover along with an influx of ferns, followed by dicotyledonous seedlings and saplings, and finally small trees. More than one-half of the arborescent species growing in dwarf forest are endemic to Puerto Rico where they play a prominent role in post disturbance recovery; moreover, 85% of the trees do not exceed 15 m in height anywhere in the Luquillo Mountains.
doi:10.18475/cjos.v44i2.a4 fatcat:ifuuqcn5onc45hcg6hp7dph6sa