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\hypersetup{pdftitle={Dynamics of an Uneven"=aged Mixed Coniferous Forest in the Sierra Madre Oriental, Northeastern Mexico},pdfauthor={Oscar Alberto Aguirre Calderon, Javier Jiménez Pérez, Eduardo Javier Treviño Garza},pdfsubject={Tropentag 2010: Abstract},pdfkeywords={Forest development modelling, Mexico, Mixed forest},pdfpagemode=None,colorlinks=true}
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\parbox[b]{13.4cm}{\centering \large{\textbf{Tropentag, September 14-16, 2010, Zurich}}\\[1ex] \Large{``World Food System  ---\\A Contribution from Europe''\\[2ex]}}
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\begin{center}
\Large{\textbf{Dynamics of an Uneven"=aged Mixed Coniferous Forest in the Sierra Madre Oriental, Northeastern Mexico\footnote{\textbf{Contact Address:} Oscar Alberto Aguirre Cal\-de\-ron, University of Nuevo Leon, Departement of Silviculture, Carretera Nacional km. 145, 67700~Linares, Mexico, \mbox{e-mail}: \email{oaguirre@fcf.uanl.mx}}\\[0.8ex]}}
\normalsize{\textsc{Oscar Alberto Aguirre Cal\-de\-ron, Javier Jiménez Pérez, Eduardo Javier Treviño Garza}}
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\begin{itemize*}
\item[]{\small{\textit{University of Nuevo Leon, Departement of Silviculture, Mexico}}}
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\index[author]{Aguirre Cal\-de\-ron, Oscar Alberto}
\index[author]{Jiménez Pérez, Javier}
\index[author]{Treviño Garza, Eduardo Javier}
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\textbf{Abstract}
\begin{abstract}
\normalsize{
The results of a detailed research on growth increment carried out in a 1.24 hectare uneven"=aged (14 to 126 years) mixed stand composed by \textit{Abies vejari}, \textit{Pseudotsuga menziesii}, \textit{Pinus ayacahuite} and \textit{Pinus hartwegii}, located in the Sierra Madre Oriental, Mexico are presented. Based on increment cores obtained at \mbox{1.3\,m} height, the age, the 10 years diameter increment and basal area increment of each tree were determined. The relationships between diameter increment and diameter and between diameter increment and age were tested for each of the four tree species. High multiple correlation coefficients were obtained by examination of the relationship between basal area increment (ig) of the trees and diameter (d1.3), age and different crown parameters (crown projection area (Krs), crown surface area (Krm1, Krm$^{3}$) and surface area of the light crown (Lkrm). According to all these comparision parameters, the 2 pinus species showed a higher basal area increment than fir and douglas fir. The relative basal area increment (ig/Krm1; ig/Krm$^{3}$) decreases first abruptly with increasing crown surface area and later on smoothly and is higher for the non tolerant species than for Abies and Pseudotsuga. Due to very different crown forms for the four tree species, the development of the relative basal area increment as a function of crown projection area (ig/Krs over Krs) is also very different. In contrast to even"=aged pure stands and to selection forests, the relative increment (ig/Krm; ig/Lkrm) of all species in the lower height zone (B) is equivalent or higher than in the upper height zone (A). This research was supported by the Comisión Nacional Forestal, Project: CONAFOR-2007-C01--71447, and by the Universidad Autónoma de Nuevo León (PAICYT).







}

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\noindent \textbf{Keywords:} Forest development modelling, Mexico, Mixed forest
\index[key]{Forest!development modelling}
\index[key]{Mexico}
\index[key]{Mixed forest}
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