Temperature accelerates the rate fields become forests.

Area of Science:

• Ecology
• Forest Ecology
• Plant Ecology

Background:

• Secondary succession, the transition from herbaceous to woody ecosystems, occurs faster at lower latitudes.
• This pattern may be influenced by temperature's direct effect on tree growth or by intensified tree-herb competition in fertile northern soils.

Purpose of the Study:

• To investigate the mechanisms driving faster secondary succession at lower latitudes.
• To determine the roles of temperature and soil fertility in tree seedling growth and survival during succession.

Main Methods:

• Conducted manipulative experiments at six sites across the Eastern United States (30-43° N).
• Varied soil fertility and herbaceous species composition.
• Monitored the growth and survival of four early successional tree species over two years.

Main Results:

• Tree seedling mass after two years strongly correlated with mean growing season temperature, irrespective of species or soil treatments.
• Warmer temperatures enhanced seedling growth directly.
• Warmer temperatures reduced competitive pressure from herbaceous plants, further benefiting tree seedlings.

Conclusions:

• Temperature is a key driver of secondary succession rates.
• Increasing temperatures are likely to accelerate the transition of temperate fields to forests.
• Understanding these mechanisms is crucial for predicting ecosystem changes in a warming world.