Mortality correlates with tree functional traits across a wood density gradient in the Central Amazon

Area of Science:

• Tropical ecology
• Forest dynamics
• Plant physiology

Background:

• Tree mortality mechanisms in diverse tropical ecosystems are poorly understood.
• Plant functional traits offer potential links between physiology and performance but require further investigation.
• Rising tree mortality in the Amazon highlights the need to understand species vulnerability.

Purpose of the Study:

• To investigate the association between wood density, acquisitive plant functional traits, and tree growth and mortality rates in the Central Amazon.
• To determine if specific traits predict species performance and forest vulnerability under climate stress.

Main Methods:

• Felled 17 trees of varying wood density for detailed analysis of 27 functional parameters.
• Assessed traits including wood density, leaf traits, and hydraulic capacity.
• Related individual tree traits to 30-year stand-level growth and mortality data from permanent plots.

Main Results:

• Lower wood density correlated with acquisitive traits, higher hydraulic capacity, and greater foliar nutrients.
• Trees with lower wood density exhibited higher growth and mortality rates.
• Higher wood density was associated with conservative traits like smaller leaves and lower water content.

Conclusions:

• Lower wood density is part of a trait suite promoting high resource acquisition, fast growth, and increased mortality risk.
• This provides a functional framework for predicting species performance and Amazonian forest vulnerability to climate change.
• Understanding these trait-mortality links is crucial for forest management and conservation efforts.