Subantarctic rain forest of Magellanic Chile: Distribution, composition, and age and growth rate studies of common forest trees

Author(s):  
Steven B. Young
Radiocarbon ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 1-6 ◽  
Author(s):  
A A Mozeto ◽  
Peter Fritz ◽  
M Z Moreira ◽  
E Vetter ◽  
Ramon Aravena ◽  
...  

Evergreen trees in the tropical rain forest of the Amazonas Basin can produce growth rings which are not necessarily related to annual events. Therefore, estimation of growth rate cannot be done by dendrochronology. This report presents a technique for determining the growth rate of these trees based on radiocarbon measurements of two segments of equal radial distance from the outer part of the tree trunk. The measured 14C activity is compared to local 14C fallout and growth rates are derived from models taking into account bomb 14C effects. Eleven trees from various parts of the Amazon Basin were analyzed. The average growth rates range from ca 5 to > 40 yr per centimeter corresponding to extrapolated ages from ca 60 to > 400 yr.


2021 ◽  
pp. 1-13
Author(s):  
Jennifer Read ◽  
Gordon D. Sanson ◽  
Martin Burd ◽  
Kathryn Allen ◽  
Quan Hua ◽  
...  

Abstract Cerberiopsis candelabra Vieill. is a long-lived, monocarpic (= semelparous) and mass-flowering rain-forest tree, endemic to New Caledonia. Population size structures suggest establishment has been episodic, followed by a recruitment gap that might signal population decline. Here, we use age structures based on tree rings to better assess population dynamics and persistence, and investigate influences of tree size, age and growth rate on flowering. Age structures of populations surveyed in 2007–2008 were unimodal, with establishment over c. 15–81 y, followed by a recruitment gap of c. 23–79 y. Seedling mortality was generally high. High densities of flowering trees or large-scale exogenous disturbances may be necessary for in-situ regeneration. There was no evidence of a simple flowering threshold: flowering in 2017 occurred across a wide range of tree size, age and growth rate. Instead, evidence suggested that size and age at flowering may vary among plants depending on their growth trajectory. Environmental triggers of flowering were not identified by dating tree establishment, but the last three mass-flowering events occurred in years of tropical cyclones. Regeneration and persistence might be facilitated if large-scale disturbances trigger flowering, improving reproductive efficiency by synchronising flowering and linking reproduction with environmental conditions that enhance seedling recruitment.


1986 ◽  
Vol 64 (5) ◽  
pp. 1046-1049 ◽  
Author(s):  
J. D. DeAngelis ◽  
T. E. Nebeker ◽  
J. D. Hodges

Formation of radial resin ducts and their associated secretory cells in loblolly pine (Pinus taeda L.) is influenced by the age and growth rate of the annual ring in which the ducts are formed. The spatial pattern of radial ducts on the tangential plane is nonrandom, exhibiting a regular or dispersed pattern. A significantly higher density of radial ducts was found in the inner, first-formed growth rings at all heights within the tree. Radial duct formation was found to be positively correlated with radial growth rate, when growth rate is expressed as increment of cross-sectional area growth. These findings may partially explain why older, slower growing trees tend to be more susceptible to attack by the southern pine beetle, Dendroctonus frontalis Zimmermann, and associated microorganisms, since the resin-producing system is a primary defense against these agents.


2017 ◽  
Vol 15 (1) ◽  
Author(s):  
Rosa S. Santos ◽  
Marcus R. da Costa ◽  
Francisco G. Araújo

ABSTRACT Studies on age and growth of fish populations have direct application in fisheries and contribute for policies of conservation. Our aim was update information on the Micropogonias furnieri growth parameters based on sagittae otoliths annulis readings, and we expected that the studied population from Southeast Brazil can reach more longevity than the reported in the available literature. We examined 286 individuals between August-2010 and July-2011 from Ubatuba Bay, SP. The Total Length ranged 200-480 mm. The determined growth parameters were: Males, L∞ =523.4mm, k = 0.05×year-1, t0 = -8.78 year; Females L∞ = 573.5mm, k = 0.06 × year-1, t0 = -7.49 year. The MI and % of edge type evidenced the formation of one ring per year during autumn/winter, coinciding with low temperature and low growth rate. These results differed from those reported for the Vazzoler’s Population I (summer), and we detected higher longevity (45-48 years) as compared with the recorded in the available information.


2012 ◽  
Vol 69 (1) ◽  
pp. 61-69 ◽  
Author(s):  
Frederico Augusto Guimarães Guilherme ◽  
Tiago Osório Ferreira ◽  
Marco Antonio Assis ◽  
Pablo Vidal Torrado ◽  
Leonor Patrícia Cerdeira Morellato

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