Event Title

Population Dynamics of the Mexican Beech, an Endangered Tree Species

Event Website

http://www.nafew2009.org/

Start Date

6-22-2009 12:00 AM

End Date

6-26-2009 12:00 AM

Description

Success in the reproduction of a species depends on the functional responses to biotic and abiotic factors of its developmental stages. With the objective to analyze the population dynamics of Fagus grandifolia subsp. mexicana in relation to site and environmental factors, we conducted a study on the structural changes of the population within a plot of 4,800 m2, during a period of three years. This species, restricted to the Sierra Madre Oriental (East Mountain Range) along the distribution of the mountain cloud forest, is considered an endangered species since only 10 small populations have been reported. We divided the population into small saplings (0.6cm < 2m) which showed a high recruitment rate (4,095 ind. ha-1). The damage rate was consistently low in all developmental stages, only eight individuals died during the three year period. The Absolute Growth Rate (AGR) and Relative Growth Rate (RGR) in height for small saplings was 0.115 m m-1 year-1, and 0.099 m m-1 year-1, respectively. The individuals with dbh 1.0 cm showed a mean AGR and RGR of 0.086 and 0.010 cm cm-1 year-1, respectively. A highly significant positive correlation was detected between small sapling density and percentage of photosynthetic photon flux density. The high recruitment rate of small saplings was strongly correlated with high light availability in the understory, located preferably under the influence of canopy gaps. In spite of the fact that the species is considered to be shade tolerant, its regeneration is favored by the formation of canopy gaps.

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Jun 22nd, 12:00 AM Jun 26th, 12:00 AM

Population Dynamics of the Mexican Beech, an Endangered Tree Species

Success in the reproduction of a species depends on the functional responses to biotic and abiotic factors of its developmental stages. With the objective to analyze the population dynamics of Fagus grandifolia subsp. mexicana in relation to site and environmental factors, we conducted a study on the structural changes of the population within a plot of 4,800 m2, during a period of three years. This species, restricted to the Sierra Madre Oriental (East Mountain Range) along the distribution of the mountain cloud forest, is considered an endangered species since only 10 small populations have been reported. We divided the population into small saplings (0.6cm < 2m) which showed a high recruitment rate (4,095 ind. ha-1). The damage rate was consistently low in all developmental stages, only eight individuals died during the three year period. The Absolute Growth Rate (AGR) and Relative Growth Rate (RGR) in height for small saplings was 0.115 m m-1 year-1, and 0.099 m m-1 year-1, respectively. The individuals with dbh 1.0 cm showed a mean AGR and RGR of 0.086 and 0.010 cm cm-1 year-1, respectively. A highly significant positive correlation was detected between small sapling density and percentage of photosynthetic photon flux density. The high recruitment rate of small saplings was strongly correlated with high light availability in the understory, located preferably under the influence of canopy gaps. In spite of the fact that the species is considered to be shade tolerant, its regeneration is favored by the formation of canopy gaps.

https://digitalcommons.usu.edu/nafecology/sessions/posters/25