Monthly archive for May 2013

Earthwatch Teams over the years

Earthwatch Teams over the years

Wastewater Garden at Las Casas de la Selva since 2004

Wastewater Garden at Las Casas de la Selva since 2004

Volunteers at Work Feb/March 2013

Volunteers at Work Feb/March 2013

We always appreciate the help that our volunteer groups provide, and help us get this project off the ground, sometimes literally!

Thank you to students of: Appalachian State University, Pepperdine University, Vanderbilt University, Northeastern University, and Northwestern University.




Frogging at Las Casas de la Selva!

3T’s Eye On The Rainforest Series: Paintings and Drawtings

Humanure Compost Toilets

Humanure Compost Toilets


Since February 2013, our new composting toilets have proved a huge success with everyone who has used them.

First Tree planted

First Tree planted


John Druitt and Sally Silverstone plant the first pine tree in 1984.


BOIScoverNELSON MARK, SILVERSTONE SALLY, REISS KELLY, ROBERTSON MOLLY, VAKIL THRITY, 2011. Enriched secondary subtropical forest through line-planting for sustainable timber production in Puerto Rico. Bois et Forets des Tropiques, #309 (3): 51-61]

1984: In general the plantation design was to plant at approximately 3m (10 ft) spacing within the lines and 10m (32.5 ft) from line to line through the forest. In the process of line planting, larger trees and valuable native timber species were left in place and the lines continued with a gap left around them. This technique closely mimics a medium-sized tree fall gap, in which the forest floor litter and soils are undisturbed, but the above ground nearby competition is removed, such as vines and overhanging branches.
19 study plots, 1 acre (0.4 hectare) in size 16 plots of mahogany 3 plots of mahoe. 997 trees studied. Complete sets of reading taken twice. Range 24 to 42 mths between readings.

SURVIVAL RATE Mahogany plantings – 28% approx (dependent on plot aspect- see results, sw best) Initial planting approx. 370 trees per hectare (148 trees per acre) Mahoe plantings – 66%. Initial planting approx. 415 trees per hectare (166 trees per acre) DBH Mahogany trees are increasing in dbh by an average of 0.6 cm per year Mahoe are increasing by an average of 0.91 cm per year. HEIGHT since planting: Mahogany has grown in height at a rate of approximately half a meter per year. Mahoe at a rate of approximately one meter per year.

INDICATIONS The growth data indicate the Mahoe plantation has been far more successful than the mahogany in terms of wood production.  At current rates of increase it would take the mahogany at Las Casas another 27 years to get 30 cm dbh trunks for logging, giving a total time from planting to harvest of 43 years. It is currently possible to harvest marketable wood from the mahoe at 15 years. Current conservative estimates for standing marketable wood for mahoe are approximately 58 cubic meters per hectare (25,000 board feet per hectare or 10,000 bd ft per acre). This makes the Mahoe a good candidate for sustainable forestry management where the aim is to get the trees on a cycle of harvesting and replanting to provide a continuous income. A final evaluation of this line planting method as a model for sustainable forestry will  be possible when trees are being annually harvested selectively, replanting begins, and the wood and products successfully sold for profit. Future challenges with the Mahoe plantations will involve working out the best thinning and replanting strategies, (and dealing with issues of extraction on slopes, drying techniques, and forest road and bridge repairs after nearly thirty years and two hurricanes). The challenge is on.

Ongoing research on the Mahoe plantation: 2010 – 2012
Jimena Forero is pursuing a PhD Degree at the University of Puerto Rico, Rio Piedras campus. As part of her dissertation she is describing the stand density and the canopy structure of our mahoe enrichment plantation in order to make recommendations for its management. Using our three 1-acre permanent mahoe plots, she has, with the help of undergraduates and Earth Watch volunteers conducted a forest inventory over two years (2010-2012) of these plots at Las Casas de la Selva. Her academic supervisor is Dr. Jess K. Zimmerman, Environmental Sciences professor at University of Puerto Rico, Rio Piedras. Another part of her dissertation involves interviewing artisans all over the island, who use forest products.


2000-2004 Amphibians: Amphibians are especially useful as biological monitors of environmental health (Wake, 1991). Because in Puerto Rico frogs are the most important vertebrate nocturnal carnivores, a change in their population dynamics could have an important effect on the forest food web (Joglar, 1998). Thus, monitoring amphibians at Las Casas de la Selva was a suitable way to assess the impact of a line-planting forestry approach to tropical forest ecosystems. Main difference between the studied forested areas was that one had been disturbed to plant trees of potential economic value (line-planting), while the other area had been left undisturbed. There was no difference in species composition between the two areas studied.  Eleutherodactylus coqui and E. wightmanae are the two most common species in both forests, with occasional sightings of E. portoricensis.

We were happy to note:
Analysis of variance (ANOVA) of mean relative abundance of the two most common species revealed no significant difference between forests.

This is encouraging data.

These results suggest that the degree of disturbance caused by planting economically valuable trees had no effect on amphibian diversity or density in Patillas, Puerto Rico.  At a time when the impact of anthropogenic activities on amphibian populations are being evaluated (Stuart et al., 2005), it is important to show that the type of forestry enrichment practiced at “Las Casas de La Selva”, did not have a negative impact on frog abundance. Our work in Las Casas de la Selva is the first record of population densities of E. coqui in the central cordillera of Puerto Rico, and the first record of population densities for E. wightmanae.

At a time when amphibian populations are declining all over the globe, and populations of these two species are declining at El Yunque, these data from Patillas represent a very valuable baseline that will allow us to monitor population fluctuations and potential declines associated to climate change or disease. Chytrid fungus Since June 2004, various species of frogs at Las Casas de la Selva have been sampled for the incidence of a pathogenic chytrid fungus, Batrachochytrium dendrobatidis (Bd). This fungus is specific to amphibians and has been associated to their decline in various parts of the world (Longcore, 1999), including Puerto Rico (Burrowes et al. 2004). Tissue is taken from toe clippings and/or ventral skin scrapes, and analyzed for the chytrid DNA via specific PCR diagnostic methods. Results show the presence of chytrids in Patillas as early as 2005. At present, the level of incidence of Bd infection in Eleutherodactylus coqui is of 50 % and in E. wightmanae is 44 %. Biodiversity of Trees: Overall the line-planting program has resulted in a small increase in overall diversity of tree species in those areas. See results in the full paper, link above.

COMING SOON: Jump into our current world of frogs, snakes, lizards and more with Norman Greenhawk, who has been carrying out herpetological surveys in the forests of Las Casas de la Selva for the last five years.


Ongoing Coqui frog research at Las Casas de la Selva: 2010 – 2012  Patricia Caligari (center) is pursuing a Masters Degree at University of Puerto Rico, and  as part of her thesis is sampling for chytrid in three species of endemic frogs in different parts of Puerto Rico, including Las Casas de la Selva. Her crew of undergraduate students help in the field and lab with DNA extraction. Her advisor is Dr. Patricia Burrowes, co-author of our paper above. More info



All studies are a building block in the more complex strategy of developing techniques to both satisfying human needs and conserving the resource base.” Ariel Lugo



Since 2000, the team at Las Casas de la Selva has been honored to work with volunteers from all over the world thanks to the sponsorship of The Earthwatch Institute. We greatly appreciate the decision that volunteers make to come here and help us accomplish our goals towards sustainable management of this forest. With the data we have been gathering we are able to evaluate the needs and direction of further studies, and implement relevant strategies and land and timber management plans.

Puerto Rico is currently approximately 57% forested, mostly by young secondary forest. The period of economic and cultural change from the 1950s to 1990 in Puerto Rico is seen as proportionally resulting in the largest event of forest recovery anywhere in the world.  It is crucial that we understand the ecology of this type of forest, if we are to utilize its timber and other forest products in economically and ecologically viable ways. This project increasingly becomes a living demonstration in new models for approaches to forest management in Puerto Rico and the Caribbean.

With the challenge of our terrain, climate, and steep (often muddy) slopes, it has been a joy to see so many volunteers overcome personal difficulties, and really open themselves to the joy of the outdoor life. Many volunteers have changed the course of their studies or careers after experiencing life and work with us in this stunning, edifying landscape.We have enjoyed the company of all who have trekked through the forest with us, identifying, collecting, and measuring, and equally enjoyed homestead social interactions at the end of a long day. Thank you for involving yourselves in learning about our biosphere with us.

On an Earthwatch Expedition in the Puerto Rico Rainforest: Earthwatch volunteers will be trained in a variety of tasks, which may include measuring trees, counting and identifying lizards or frogs, helping to tag and identify vine species, and helping to set up new experimental plots for planting different tree and shrub species. You will be in beautiful, tropical rainforest areas, sometimes climbing up steep hillsides, and sometimes following fast flowing rivers. You may also have the chance to join a night expedition into the forest to help count coqui frogs. During your recreational time you will be able to enjoy hikes, take dips in nearby rivers, take part in some forest related craft activities, use the project library to learn more about the ecology of the area, or just relax and enjoy an area of rainforest land that very few other people have had a chance to visit. There will also be an opportunity to take a salsa dancing class and to experience the local culture and cuisine.

EW 2012



Principal Investigators for Earthwatch Expeditions at Las Casas de la Selva since 2000: Dr. Mark Nelson, Sally Silverstone, Dr. Patricia A. Burrowes, Dr. Rafael L. Joglar,  Thrity J. Vakil, Molly Robertson, Norman Greenhawk, Patricia Boyko, Jimena Forero, & Marta Edgar.

Previous and current advisors and mentors: John P. Allen (Global Ecotechnics), William F. Dempster (Global Ecotechnics), Frank H. Wadsworth, Peter L. Weaver (IITF), Jess Zimmerman (Luquillo LTER, UPR), Pedro Acevedo-Rodriguez, (Smithsonian), D. Jean Lodge, (US Forest Service), Joe M. Wunderle (IITF), Jill Thompson, (El Verde Field Station).

Earthwatch Field Reports

2004 (PDF 25.5KB)
2006 (PDF 93.6KB)
2007 (PDF 41.7KB)
2008 (PDF 265.0KB)
2009 (PDF 998.4KB)
2010 (PDF 1.26MB)
2011 (624.0KB)

Research 2000 -2010

On-going Scientific Objectives: 2010 and beyond

See more on Earthwatch Institute website about how to participate in a scientific expedition in the rainforest.

Earthwatch Teams Gallery

An archive of images on the fungi of Las Casas de la Selva: an  educational reference and handy guide.

See presentations by  Earthwatchers

TVREF Collaborations

2013 – 2015 Cooperative project between Tropic Ventures Research Education Foundation, US Partners for Fish Wildlife and The Earthwatch Institute.


This program has been formulated to protect endangered flora and fauna by planting endangered endemic tree species, and working on habitat enhancement in subtropical wet forest. The location and the quality of the habitat of the 930-acre forest property of Las Casas de la Selva is ideal for the establishment of projects toward the recovery of various endangered endemic tree species.  The property’s north-eastern border adjoins the Carite State Forest which contains another 6,660 acres of subtropical wet mountain forest land.

Tropic Ventures Research & Education Foundation are collaborating with US Fish and Wildlife Service (FWS) to develop habitat enhancement and restoration projects that benefit endangered endemic species of Puerto Rico.  The animals include the Puerto Rican boa (Epicrates inornatus), broad-winged hawk (Buteo platypterus brunnescens), Puerto Rican  sharp-shinned hawk (Accipiter striatus venator), the Guajon  coqui frog (Eleutherodactylus cooki),  and Puerto Rican plain pigeon (Columba inornata wetmorei).

Most of these species have been identified on this land, which makes it eminently suitable for their long-term habitat protection & enhancement.  The area also provides habitat for several listed trees that have been identified within this geographical area (Eugenia haematocarpa and Callicarpa ampla).  The area also harbors habitat for two Candidate Species; the elfin-woods warbler (Dendroica angelae) and the vine/shrub Gonocalyx concolor.  The proposed project will also focus on the establishment of two experimental populations of the federally listed tree Styrax portoricensis.  Furthermore, the area to be enhanced is part of the Rio Grande de Patillas upper watershed, which serves a large regional population with potable water, and will benefit the water quality of this river by reducing soil erosion.

As part of this project, Tropic Ventures Research and Education Foundation agree to maintain and protect the specific areas to be enhanced or under restoration practices for a period of at least 10 years.  The areas for habitat enhancement will not interfere with other areas of the property which have been planted with forest enrichment trees, and is already in a program of sustainable management including selective harvesting of timber trees. Las Casas de la Selva is certified as Stewardship Forest and under the auspices of the Puerto Rican Department of Natural Resources (DNR) and the International Institute of Tropical Forestry (IITF) has an approved Stewardship Management Plan. Tropic Ventures Research & Education Foundation has a contract  with Tropic Ventures (the managing entity) to conduct scientific studies and educational research work on the entirety of the land for the next 50 years.

Earthwatch volunteer collaboration

Initially Earthwatch volunteers will be engaged in the process of site selection, site mapping, tagging and planting, measuring the saplings, and data collection. A biologist from FWS may accompany us on some these expeditions to assist in the process. See below for long-term monitoring process.  All tree work is dependent on weather and care will be taken on steep slopes as always. There will always be nursery work, which may include pruning, care and maintenance of young seedlings, and of endangered tree species.

1. ENDANGERED SPECIES: Establishment of new populations of Styrax portoricensis. Establish at least two populations composed of about 50 individuals each in approximately 2 acres. Expected survival is 75% after the 2nd year of planting. Styrax portoricensis, locally known as palo de jazmin, is a species of flowering plant in the family Styracaceae. It is one of the rarest endemic trees of Puerto Rico and is found only in the northeastern Luquillo Mountains (Sierra de Luquillo) and the north-central Cayey mountains (Sierra de Cayey).

2. HABITAT ENHANCEMENT: Establishment of a shade nursery for caring and sheltering of saplings of threatened endemic species until planting.

3. LONG TERM MONITORING:  The aim of this effort is to monitor the initial survival, growth rate, and success of the reintroduced material to ensure the best contribution to the recovery of the species.

4. REPORTS: Annually

5. OUTREACH: We will develop an outreach project to promote the recovery efforts and to educate the local community and visitors. This program will include fliers, brochures, and boards and signs along trails etc.


 The Forest Products Assessment Project


This project has enabled Andrés Rúa to visit with sawmill owners over the island, interview dozens of artisans who work with forest products, as well as large & small scale wood & product dealers. The project aims to investigate use of forest products in Puerto Rico; where wood is coming from, what types of wood, who are the buyers, and what other forest products are in demand and use?

A symposium in April 2012 brought together over eighty people, ranging from foresters, arborists, woodworkers, DRNA staff, artisans, architects, professors, and UPR students, the symposium was hugely informative. The event was dedicated toCarlos Domínguez Cristóbal, author of “Panorama historico forestal de Puerto Rico”, and to recently retired forester Dr. Peter L. Weaver from IITF.

The Forest Products Assessment project continued with an in-the-field event in August 2012 led by Andrés Rúa. A pine tree was felled by arborist Andre Sanfiorenzo, hauled out by tractor, and milled. The event was to bring together and give those who shown an interest at the last Symposium the opportunity to actually partake in a timber project. Andrés showed the mill at work and several people had the chance to operate it. After a gourmet lunch, the afternoon continued in el teatro where lively and heated discussions dealt with the next steps to creating an intelligent future for timber production and forest products in Puerto Rico.

March 2013 saw the beginning of the second phase of the Forest Products Assessment, with a meeting at the International Institute of Tropical Forestry, (Images here) and then in in May 2013 at the University of Cayey,  (Images here). More details on

CADA, Council for the Development of Agro-forestry, founded by Andrés Rúa and 3t Vakil, May 2013, was born from forestry discussions, which began with Frank H. Wadsworth in private meetings in 2008. The open membership includes individuals from universities and the private sector, members of Government agencies, and many other institutions, all brought together with an over-arching interest in the development of policies pertaining to the sustainable and intelligent use of all Puerto Rico’s valuable & unique natural resources.


Dec 2014 Symposium and Wood Expo at The International Institute of Tropical Forestry.
SYMPOSIUM-&-WOOD-EXPO-2014poster  Smyposium1Dec2014a
L-R: Luis Soto, (Land Authority Director) Carmen Guerrero, (Secretary of DNR), Connie Carpenter, Magaly Figueroa, (USDA State & Private Forestry), Andrés Rúa, 3t Vakil, (Tropic Ventures) Magha Garcia, (Director Pachamama Organic Farm), Sheila Ward, (Mahogany for the Future), Edgardo Gonzalez (Landscape Conservation Center).

 DNR conference in Adjuntas Aug 2014
Aug 28-29: Andrés attends two days of a 5-day DNR conference in Adjuntas, with professors from CATIE (Centro Agronómico Tropical de Investigación Enseñanza)
Nov 2014 Artisan Fair – Convention Center, San Juan.
 artisanfairnov2014  artisanfair-nov2014
The 6th Artisan Fair of PR, with a workshop for turners. We collected ‘waste’ wood from the streets and provided the turners with wood for three days of public turning classes. In return we had two tables for sales & marketing of our woods.

April 2014   Talk at School of Fine Art & Industrial Design
 School-of-Fine-Art-Talk-23-April-2014-(3)  School-of-Fine-Art-Talk-23-April-2014-(8)
Nov 2014 DNR Symposium: ‘Landscape Management of PR’ An interdisciplinary exchange for conservation & sustainable development. Luthiers of PR held an event to see our collection of Puerto Rican woods and to discuss a collaborative future.
 andres-at-DNR-symp-2014  LuthiersJune2014b


 CADA-4th-March-2014  CADA-6th-May-2014
CADA meeting 4th March 2014
CADA meeting 6th May 2014
 DNR-meetingGroup-Photo-12-June-2014  cada-26-sept2014
12th June 2014: Meeting with Secretary of DNR, Carmen Guerrero (far left). 26th September 2014: meeting at IITF
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