The Peracchi Management Project (henceforth ‘Agua Azul’) is an industry-owned reforestation and management project located 9 km southwest of Agua Azul, a small agricultural community midway between Xinguara and Tucumã on unpaved state highway PA-279, approximately 115 km northwest of Marajoara. Topographic relief in this region is more pronounced than at Marajoara, with extensive hilly areas where steeper slopes rise 20–40 m across 200- to 1000-meter distances. Soils grade from gray or white at slope bottoms through yellow and red-yellow to dark red at slope tops. Equally extensive areas at Agua Azul are quite flat, however, with pale to dark gray sandy soils drained by meandering first- and second-order seasonal streams, and it is in these areas where mahogany is (or was, before extraction) found at commercial densities. Mahogany occurs within steeper areas, but at far lower, non-commercial densities.
Agua Azul consists of adjacent cleared and forested areas covering roughly 1000 and 250 ha, respectively. Nursery-grown mahogany seedlings were outplanted by the managing company from 1994–1997 into bulldozed flats between hedgerows spaced ~100 meters apart in the cleared area. In 1995 approximately 200 hectares remained in heavily thinned forest whose understory had been slashed in a crude shelterwood treatment. All overstory species except mahogany were removed from this area in early 1997, leaving > 75% of the mahogany trees included in the sample exposed to full sunlight in a pasture-like setting. What closed forest survived at Agua Azul was low, highly disturbed, and fire-prone. Original forest composition was similar to that at Marajoara, though with exceptionally high densities of jatobá (Hymenaea courbaril) and caximbeira (Cariniana domestica, Lecythidaceae).
We first visited the Agua Azul site in July 1995, and returned to tag and map mahogany trees there in ~600 hectares in June 1996. The sample mahogany trees were all smaller than 65 cm diameter. These were survivors of a first cut in the mid 1980s which removed the population’s larger stems; stumps can be found at varying densities throughout the area. Most sample trees grow in clusters strung along the banks of or adjacent to seasonal streams, mixed by size class. Some trees also grew at the tops of short steep slopes above drainage flats, in rocky gray sands. Similar to Corral Redondo, research objectives at Agua Azul focused on annual diameter growth, fruit production, and reproductive phenology. Access was by dirt track from the PA-279. Peracchi maintained a barraco at the west end of the project area where we camped during each dry season visit. Trails linking mahogany trees were re-opened annually and covered roughly 15 km. To protect trees standing exposed in secondary vegetation from groundfires, aboveground regrowth was removed each dry season to a 3-m radius of surviving trees.
We have been unable to return to the Agua Azul site since landless agriculturists occupied the site in 2002. The fate of mahogany trees there is unknown but we assume that the site has been extensively cleared and burned for crops and pasture.
Grogan J (2001) Bigleaf mahogany (Swietenia macrophylla King) in southeast Pará, Brazil: a life history study with management guidelines for sustained production from natural forests. PhD dissertation, Yale University, New Haven, CT, USA. 422 pp.
Grogan J, Schulze M & Galvão J (2010) Survival, growth and reproduction by big-leaf mahogany (Swietenia macrophylla) in open clearing vs. forested conditions in Brazil. New Forests 40: 335-347 (http://www.treesearch.fs.fed.us/pubs/37823).