Forest structure and woody plant species composition along a fire chronosequence in mixed pine–oak forest in the Sierra Madre Oriental, Northeast Mexico Marco Aurelio Gonza ´ lez-Tagle a, *, Luitgard Schwendenmann b , Javier Jime ´nez Pe ´ rez c , Rainer Schulz d a Institute of Silviculture, Georg-August University Go ¨ttingen, Bu ¨sgenweg 1, D-37077 Go ¨ttingen, Germany b Tropical Silviculture and Forest Ecology, Burckhardt Institute, Georg-August University Go ¨ttingen, Bu ¨sgenweg 1, D-37077 Go ¨ttingen, Germany c Institute of Silviculture, University of Nuevo Leon, Apartado Postal # 1, 67700 Linares, Nuevo Leon, Mexico d Institute of Forestry Biometry and Informatics, Georg-August University Go ¨ttingen, Bu ¨sgenweg 4, D-37077 Go ¨ttingen, Germany 1. Introduction Fire disturbance is a major factor driving patterns of vegetation structure and composition in natural ecosystem (Whelan, 1995). Human activities can influence natural fire regimes by increasing fires in forests that would seldom burn under natural conditions (Goldammer, 2003), but in the other hand, suppressing natural fires in fire dependent ecosystems may lead to infrequent, catastrophic fires due to a build-up of flammable material (or fuel loading) (IUCN, 2003). To determine the extent of human influence on natural fire regimes, many research projects have focused on fire effects and forest structure in many countries, especially in the USA, Canada, and Australia. These countries have developed strategies to manage forest fires, but have also learned to accept fires as a natural disturbance that must be integrated into restoration programs, conservation, and management (Wouters, 1994; Bergeron et al., 2003; Russell et al., 2004; Stephens and Ruth, 2005). According to Rodrı ´guez-Trejo and Fule ´ (2003), forest fires are widespread throughout Mexican forest ecosystems. In 1998, around 9000 fires burned approximately 220,000 ha of forest land and in 2003, around 100,000 ha of forested area were lost (CONAFOR, 2006). A number of studies have focused on the historical reconstruc- tion of fire regimes in the pine–oak forests of the Sierra Madre Forest Ecology and Management 256 (2008) 161–167 ARTICLE INFO Article history: Received 13 January 2006 Received in revised form 9 April 2008 Accepted 10 April 2008 Keywords: Pine–oak forests Fire Forest structure Woody plant species composition Sierra Madre Oriental Mexico ABSTRACT Although wildfires are occurring frequently in the pine–oak forests in the Sierra Madre Oriental (northeastern Mexico), data on post-fire succession and forest structure are still rare. Our objectives were to (1) assess the changes in woody plant species composition after fire and to (2) to relate successional patterns to environmental variability. Based on their fire history 23 plots were selected in the Parque Ecolo ´ gico Chipinque (PECH). Changes in forest structure across the chronosequence of burned stands were deduced from density, height and diameter measurements of trees and shrubs (>5 cm in diameter) in all plots of 1000 m 2 . Differences in woody plant species composition among the plots were evaluated using Shannon evenness measure and the Whittaker’s measure and by Hierarchical cluster analysis and Detrended Correspondence Analysis. Hierarchical cluster analysis showed a high similarity among all recently burned plots, independed of the aspect. Multivariate analysis showed that local environmental factors, including time since fire, continue to structure species composition. Oak species (mainly Quercus rysophylla) resprouted successfully after fire and dominated young post-fire stands. Pine species (Pinus pseudotrobus and Pinus teocote) only appeared 18 years after fire and were the dominating species in mature stands (62 years after fire). In contrast, woody plant species composition in older stands tended also to be influenced by factors such as aspect and by the potential solar radiation (PSR) during the growing season. The results demonstrate that in the PECH, natural regeneration is sufficient and woody plant species composition will be similar to pre-fire conditions after 60 years of succession. We conclude that the park managers should consider incorporating natural disturbance regimes into their management practices. ß 2008 Elsevier B.V. All rights reserved. * Corresponding author. Present address: Facultad de Ciencias Forestales, Universidad Auto ´ noma de Nuevo Leo ´ n, A. P. # 1, CP 67700 Linares, Nuevo Leon, Mexico. Tel.: +52 821 2124895x144; fax: +52 821 2124251x251. E-mail address: marco.gonzalez@web.de (M.A. Gonza ´ lez-Tagle). Contents lists available at ScienceDirect Forest Ecology and Management journal homepage: www.elsevier.com/locate/foreco 0378-1127/$ – see front matter ß 2008 Elsevier B.V. All rights reserved. doi:10.1016/j.foreco.2008.04.021