Pinkaití is a research forest administered by the Kayapó Indigenous People from the village of Aúkre, with technical assistance from Conservation International—Brasil. Aúkre is located at 7°41’15” S, 51°52’25” W, 185 km west of Marajoara by small plane. From there, Pinkaití lies four hours upstream by outboard canoe traveling southwest on the Riozinho River, an aseasonal tributary of the Xingu River flowing 40–60 m wide in the rainy season. The research forest covers roughly 2500 hectares. The site is an island of unlogged forest containing mahogany at variable densities surrounded by a vast forested area from which merchantable mahogany has been extracted since the mid-1980s.
Landscape at Pinkaití is similar to that at Marajoara, with gently undulating low ground punctuated by steep inselbergs rising 50–150 m. The pattern of slow or impeded drainage on low ground and predictable soil catenas across barely discernible relief repeats itself with variations. Higher clay content of hydromorphic low-ground soils tends to create boggy conditions during the rainy season. These soils retain water longer into the dry season but eventually dry brick-hard. High-ground soils are dense dark red clays rather than the paler, freely draining dystrophic sandy clays seen at Marajoara.
The forest here is structurally more diverse if compositionally less so. A handful of widely scattered emergent species, mahogany and Brazilnut (Bertholettia excelsa, Lecythidaceae) most prominent among them, tower above a low, irregular canopy. This is classic Xingu Basin liana forest. Vine tangles choke back tree regeneration in low mats covering areas several hundreds of square meters to tens of hectares. Forest stand dominance by one or a handful of tree species commonly occurs in patches at both high- and low-ground positions. Tall closed canopy forest rises on preto (black humic) soils along the high banks of second- or third-order streams draining into the Riozinho River.
The Pinkaití mahogany sample includes trees of all size classes up to 180 cm diameter in a core area covering ~600 hectares. Most are found on low ground as at Marajoara, at highest densities in boggy flats where canopies are lowest and most open. Mahogany does grow on high ground in red clays at Pinkaití but rarely so, and rarely to any great stature. We first visited the site in June 1995, returned in July 1996 to map and tag trees, and recensused annually (except in 1997) until 1999 for growth and fruit production.
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.
Norghauer JM, Malcolm JR & Zimmerman BL (2008) Experimental establishment of big-leaf mahogany (Swietenia macrophylla King) seedlings on two soil types in native forest of Pará, Brazil. Forest Ecology and Management 255: 282-291.