Branch elongation and diameter growth were temporally dissociatedin "cerrado" tree species

Davi Rodrigo Rossatto

doi:10.1590/s2236-89062009000300005

Abstract

Here is a communicating about time differences between branch and diameter growth in a tree community of ten species in Neotropical savanna ("cerrado") of Central Brazil. This work was conducted to study branch expansion and diameter growth in a period of one year between 2006 and 2007. Branch growth had begin in middle dry season and had the peak occurrence during the dry period in September, while diameter growth had begin in late dry season and peaked in the middle of wet season in December. The majority of species followed the same pattern. Branch growth did not have relation with rainfall, while diameter growth had a clear and positive relation with rainfall records. These results suggested that branch growth was not depend on rainfall but only on water status recover, while diameter growth probably depends strongly on water and to carbon assimilation that occurs after branch and leaf expansion.

Highlights

Neotropical savannas of Brazil, locally known as “cerrado”, covers about 2 million km2, which makes it the second most extensive plant formation in South America
Branch growth started during the dry period in July 2006, while diameter growth in “cerrado” tree species initiated in the late dry season in September 2006
Branch growth was not uniformly distributed throughout the year (μ = 254.78o; z = 40.28; P < 0.01), which indicates that this phenomenon occur in a specific period of the year, peaking during the end of dry season, about September

Summary

Introduction

Neotropical savannas of Brazil, locally known as “cerrado”, covers about 2 million km, which makes it the second most extensive plant formation in South America. Seasonal precipitation is characterized by two distinct seasons: one very strong dry season during the southern winter and a wet season in summer, being the most important factor determining many aspects of anatomical and physiological properties of “cerrado” plant species (Franco 2002). Plant carbon balance and growth are intimately related to the patterns of leaf flush and senescence (Reich 1995), so plants growing in seasonal environments must adjust their morphology and the activity of their branches to renewal structures and maximize their survival and productivity. The understanding of these adaptive features is crucial to identify the ecological strategies of plants concerning carbon assimilation and the use of water resources in relation to environmental constraints (Eamus 1999)

Methods

Results

Conclusion