<P> Mario Javier Fernandez - Vega is a Puerto Rican forester who uses silvicultural techniques . Fernandez is currently developing cutting edge forestry methods known as the "Borincano Model". The model capitalizes on the diversity of ecological niches in Puerto Rican forests and native disturbance regimes to formulate practices uniquely suited to the forests of the territory . About his model Fernandez has been known to comment, "Soy de aquí como el coquí" I am from here just like the coqui, a common patriotic axiom that is used to demonstrate their native ties to the island . It should be noted, although incorrect, many believe that the Coqui and its unique vocalizations are indigenous to the island of Puerto Rico . In fact however, there are thriving populations of Coquis that, like the people of Puerto Rico, have been transported to the island of Hawaii . Sadly, the Coqui a source of pride to its people, is viewed as an ecological menace in Hawaii where its song of co kee co kee is found to be an irritant by many . Needless to say that efforts to eradicate its presence in Hawaii is not a popular issue among Puerto Ricans . </P> <P> Puerto Rico is mostly mountainous with large coastal areas in the north and south . The main mountain range is called "La Cordillera Central" (The Central Range). The highest elevation in Puerto Rico, Cerro de Punta 1,339 meters (4,393 ft), is located in this range . Another important peak is El Yunque, one of the highest in the Sierra de Luquillo at the El Yunque National Forest, with an elevation of 1,065 m (3,494 ft). </P> <P> Puerto Rico is composed of Cretaceous to Eocene volcanic and plutonic rocks, which are overlain by younger Oligocene to recent carbonates and other sedimentary rocks . Most of the caverns and karst topography on the island occurs in the northern Oligocene to recent carbonates . The oldest rocks are approximately 190 million years old (Jurassic) and are located at Sierra Bermeja in the southwest part of the island . These rocks may represent part of the oceanic crust and are believed to come from the Pacific Ocean realm . Puerto Rico lies at the boundary between the Caribbean and North American plates . This means that it is currently being deformed by the tectonic stresses caused by the interaction of these plates . These stresses may cause earthquakes and tsunamis . These seismic events, along with landslides, represent some of the most dangerous geologic hazards in the island and in the northeastern Caribbean . The most recent major earthquake occurred on October 11, 1918, with seismic moment estimated at 7.5 on the moment magnitude scale . It originated off the coast of Aguadilla and was accompanied by a tsunami . </P> <P> Lying about 120 km (75 mi) north of Puerto Rico in the Atlantic Ocean at the boundary between the Caribbean and North American plates is the Puerto Rico Trench, the largest and deepest trench in the Atlantic . The trench is 1,754 km (1,090 mi) long and about 97 km (60 mi) wide . At its deepest point, named Milwaukee Depth, it is 8,380 m (27,493 ft) deep, or about 8.38 km (5.21 mi). </P>

Where is most of the farmland in puerto rico located