Fortuna

Fortuna Site Description

The 19,500 ha Fortuna forest reserve, located along the Continental Divide in Chiriqui, Western Panama, is managed by Fortuna SA for hydro-electric power generation. Details of the site are available on the Fortuna website (http://www.fortuna.com.pa/). The Fortuna reserve borders the Palo Seco Forest Reserve on the Caribbean slope of the Continental Divide in Bocas del Toro.

Although some groups of plants (e.g. Ericaceae, Arecaceae) have been extensively collected by specialists, and a provisional species list has been made for Fortuna, plot based assessments of vegetation composition and structure have not been made for this site.

Here we provide brief descriptions of five sites within the Fortuna and Palo Seco Forest Reserves spanning the wet and dry sides of the Continental Divide and varying in soil fertility. Information on species composition come from identifications made in 1 ha plots that we are currently establishing at these sites.

Hornio Valley Forest

Our sample plot is on the western slope of Cerro Hornito (right side of photo)

 

Hornito Valley Forest

Hornio Valley Forest

Canopy vegetation in the Hornito Valley

The forests of the western slope of the Rio Hornito valley (8o40'26'' N, 82o12'51"W; 1250 m elevation) are among the drier sites within the Fortuna Reserve. Two tree species in the walnut family (Juglandaceae) are abundant at this site; on the ridges Alfaroa costaricensis, and on the slopes Oreomunnea mexicana. The canopy is 30-40 m high and includes large individuals of Cedrela tonduzii, Micropholis melinoniana, Pouteria jurana, Ficus sp. and several species in the family Lauraceae.

Quebrada Samudio Forest Canopy

Canopy vegetation along Quebrada Samudio

 

Quebrada Samudio Forest

This site, along the Quebrada Samudio (8o43'52'' N, 82o14'53"W; 1100 m elevation) is close to the STRI Fortuna Station and Fortuna SA's Sitio de Presa. This is wet forest, with 30 m canopy height and a diverse tree community. Common tree species found at this site include Guarea glabra, Vochysia guatemalensis, Hedyosmum bonplandianum and Cassipourea elliptica. The understory is dominated by short-stature palms (Chamaedorea and Geonoma spp).

 

Quebrada Honda

A view across the canopy of forest at Quebrada Honda

Quebrada Honda Forest

Quebrada Honda

Interior of the Quebrada Honda forest. The large tree in the photo is Oreomunnea mexicana and can be identified by the large strips of bark that fall from the trunk and collect at the base of the tree.

This is a large patch of gently sloping forest northeast of the Fortuna dam (8o45'3'' N, 82o14'22"W; 1100 m elevation). Large patches of this forest are dominated by the canopy tree Oreomunnea mexicana, which can account for more than half the trees >10 cm stem diameter. The unusual passion-fruit tree, Passiflora tica, and a tiny understory palm, Chamaedorea verucunda, endemic to Fortuna, also occur at this site.

 

Quebrada Chorro Forest

Colpothrinax aphanopetala palms tower above the forest canopy at Q. Chorro.

Quebrada Chorro Forest

Quebrada Chorro Forest

Interior of the Quebrada Chorro forest.

Quebrada Chorro crosses the highway a few hundred meters east of Q. Honda. This site, with a canopy of 20 m height, is dominated by the canopy palms Colpothrinax aphanopetala, a species endemic to Panama, and Euterpe precatoria. Large individuals of the gymnosperm tree, Podocarpus oleifolius, are also abundant this site.

White mineral soil

White mineral soil of Quebrada Chorro.

The abrupt shift in vegetation composition between Chorro and Honda is related to a change in soil conditions in this part of the reserve. The sub-soil here is composed of rhyolite, is very nutrient-poor, and is characteristically white.

 

 

Palo Seco Forest

Our sample plot is on the western slope of Cerro Hornito (right side of photo)

Palo Seco Forest

The Palo Seco site is just across the Continental Divide from the Fortuna Reserve (8o46'43'' N, 82o11'53"W; 900 m elevation). This site has a canopy of 30 m height and supports a very diverse community of canopy trees. Several palm species occur at this site but not in other plots, including canopy and sub-canopy species Socratea exorrhiza, Cryosophila warscewiczii, and Iriartea deltoidea. The understory is dominated by dwarf palms including Asterogyne martiana, Reinhardtia gracilis, and Chamaedorea tepejilote.

 

Dept. of Plant Biology School of Integrative Biology
Program in Ecology & Evolutionary Biology University of Illinois