Leaf Phenology and Trunk Growth of the Deciduous Tree Fern Alsophila firma (Baker) D. S. Conant in a Lower Montane Mexican Forest

Abstract

in growth rates. To investigate I measure trunk growth rates, we studied a population of Alsophila firma at Las Canadas, Huatusco, State of Veracruz, Mexico. We measured leaf traits monthly for 26 mo and trunk height at the beginning and end of the study. Alsophila firma showed a unique seasonal pattern of leaf phenology, shedding its leaf pinnules when they are yellow or still green during the wet season, and 50-70% of plants stay leafless for at least 1 mo, after which strongly asynchronous leaf flush occurs. This ?e to evade higher herbivore pressure of the wet season and to t from higher light levels in the understory during the dry season when a proportion of canopy ), and 25% of the plants were fertile. Mean annual trunk growth was 17.1 ± 0.85 cm. Based on "srns (>10 m) are at least 60 yr old.The tree fern families of Cibotiaceae, Cyatheaceae and Dicksoniaceae together comprise over 640 species worldwide (Smith et ah, 2006) of which approximately 180 species occur in the neotropics (Tryon and Tryon, 1982). The neotropical center of diversity extends from the mountain ranges of Costa Rica and Panama to the Andes of Bolivia and Venezuela, with 40-50 species per country. In Mexico, there are 18 species of tree ferns (Mickel and Smith, 2004).Tree ferns are striking elements of the tropical forest vegetation and have attracted attention of ecologists for decades (

Estructura poblacional y características del hábitat de dos especies de Cyatheaceae del estado de Hidalgo

“…En México, Alsophila fi rma y Cyathea fulva son dos especies con amplia distribución dentro del BHM y están consideradas en la categoría de "sujetas a protección especial" en la legislación mexicana, por lo que es necesario que se generen datos biológicos a nivel poblacional para tener la certeza de que el uso, extracción y comercialización de los individuos de las dos especies están adecuadamente fundamentados, y que no se ponga en riesgo su supervivencia (Mehltreter y García-Franco, 2008;CITES, 2010).…”

Phenology, caudex growth and age estimation of Cyathea corcovadensis (Raddi) Domin (Cyatheaceae) in a subtropical forest in southern Brazil

“…ex Hook. (33%) from Japan; by Mehltreter & García-Franco (2008) in Alsophila firma (Baker) D.S. Conant (25%) from Mexico; and by Schmitt & Windisch (2006b) in A. setosa (8.88%), Schmitt & Windisch (2007) in C. delgadii (9.75%) and Schmitt et al (2009) in Dicksonia sellowiana (38%) from southern Brazil.…”

“…Another difficulty in estimating age is that caudex leaf scars may be densely covered by an adventitious root mantle, which, for example, can obscure the lower 1-4 m of the caudex in Alsophila firma (Mehltreter & García-Franco 2008), or by epiphytes (Schmitt & Windisch 2006). In the present study, 40% of the plants had epiphytes covering large areas of their caudices, and it was therefore not possible to count the number of leaf scars.…”

“…Although tree ferns are prominent in tropical forest vegetation (Churchill et al 1998), little is known about their phenological characteristics or the environmental triggers that affect leaf emergence, senescence and fertility (Mehltreter & García-Franco 2008) in most neotropical tree fern species. Phenology is the study of the periodicity of biological processes caused by intrinsic factors or triggered by extrinsic agents, especially the climatic variables temperature, photoperiod and rainfall, or some combination of the three (Mehltreter 2008).…”

“…Therefore, tree fern age can be estimated by measuring the increase in caudex height and assessing leaf emergence rates (Tanner 1983;Schmitt & Windisch 2006b;Sharpe & Mehltreter 2010). In the Neotropics, studies including phenological data, caudex growth rates and age estimates for Cyatheaceae, restricted to a few species and sites, were conducted by Mehltreter & García-Franco (2008), in Mexico; by Conant (1976), Seiler (1981), Tanner (1983) and Bittner & Breckle (1995), in Central America; by Ortega (1984), Arens & Baracaldo (2000) and Arens (2001), in South America; and by Schmitt & Windisch (2001;2003;2006a;2006b;, 2012 and Lehn & Leuchtenberg (2008), in southern Brazil.…”