Dendrochronological Potential in a Semi-Deciduous Rainforest: The Case of Pericopsis elata in Central Africa

Abstract

Abstract:The long-lived pioneer species Pericopsis elata is one of the rare tropical timbers on the list of the Convention on International Trade of Endangered Species, supporting the need for accurate and reliable growth data. In one planted and one natural forest in the Democratic Republic of Congo, respectively four and 37 Pericopsis stem disks were collected. The tree-ring series of planted trees were used to confirm annual tree-ring formation. For the natural forest, a tree-ring chronology with 24 stem disks ranged from 1852 up to 2008. This chronology was compared with time-series of local precipitation, resulting in a significant correlation with the second half of the rainy season (September-November). This seasonal precipitation was related with sea surface temperatures of the West Indian Ocean. Higher precipitation during El Niño years corresponded with higher tree-ring indices but differences were not significant. In addition, pointer years were rare and did not have a consistent link with extreme climatic conditions. The existence of annual tree rings encourages further tree-ring analyses of P. elata and other flagship timber species in order to further document climate-growth responses and to provide the long-term framework that is needed for sustainable management planning. OPEN ACCESSForests 2014, 5 3088

Variations Saisonnières De La Croissance Diamétrique Et Des Phénologies Foliaire Et Reproductive De Trois Espèces Ligneuses Commerciales D’afrique Centrale

“…Photo N. Bourland. 4 ) anatomiques de ces espèces permettant d'envisager l'analyse de leurs trajectoires de croissance, des données utiles à la détermination et à l'affinage des paramètres d'amé-nagement de leurs populations naturelles (Groenendijk et al, 2014 ;De Ridder et al, 2014). Néanmoins, les valeurs d'accroissement moyen périodique obtenues dans le cas de B. toxisperma sont bien plus faibles que celles observées par Fétéké et al (2015) dans la même zone.…”

“…En revanche, la croissance relativement importante observée pendant les saisons les moins sèches de l'année (PSP, PSS et GSP), où la ressource en eau demeure abondante, pourrait résulter de l'effet significatif des précipitations sur les arbres au sortir d'une période sèche, comme observé chez des espèces tropicales amazoniennes (Devall et al, 1995) et d'Afrique centrale (Couralet et al, 2010 ;De Ridder et al, 2014). Néanmoins, le principal facteur climatique explicatif de la variation saisonnière de la croissance est la température (Tmoy) pour E. suaveolens, le rayonnement (Rmoy) jouant également un rôle dans la croissance de B. toxisperma.…”

Identification of meteorological conditions in the growth of Robinia pseudoacacia on the basis of pointer years in urban conditions

“…Measurements of tree ring widths were performed in duplicate on the East-West directions of bark to core and core to bark with the use of the LINTAB TM 6 and TSAP-Win software, to a precision of 0.01 mm. LINTAB TM is a standard tool used by other researchers for measuring the tree ring widths (Motta et al, 2009;Köse & Gűnter, 2012;De Ridder et al, 2014;Jansons et al, 2015;Sensuła et al, 2015). The obtained biometric measurements for each of 54 trees in question served to determine individual sequences of tree ring widths, constituting a chronologically arranged series of tree ring widths, which were then assigned WP codes (with numbers from 1 to 54).…”

“…Due to this complexity, the relationship between the weather and tree ring widths is most clearly marked in years with extreme weather conditions (De Ridder et al, 2014). The evaluation of the role of weather conditions in the growth of trees is based on the analysis of pointer years, i.e.…”

“…when tree ring widths in all or most of the surveyed trees at a given site are greater or smaller than in the previous year (Cedro, 2012). A pointer year may sometimes be the same for different species (Okoński et al, 2014b), and its territorial range may cover not only a single site, but also a region or even an entire continent (Pourtahmasi et al, 2007;Bronisz et al, 2012;Rybníček et al, 2012;De Ridder et al, 2014). Analysis based on pointer years makes it possible to evaluate the course of meteorological conditions in a given year, characterized by a unique combination of conditions, in contrast to statistical analyses that evaluate the relationship between weather and tree ring widths over a multi-year period (Wilczyński, 2004).…”