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## Summary of CLM5.0 Updates Relative to CLM4.5

The article outlines the key updates to the photosynthesis and stomatal conductance parameterizations in the Community Land Model (CLM) version 5.0 compared to the previous version, CLM4.5.

The main changes include:

1. Default stomatal conductance calculation uses the Medlyn conductance model.

2. Vcmax and Jmax at 25°C are now prognostic and predicted via the LUNA optimization model.

3. Leaf nitrogen concentration and the fraction of leaf nitrogen in Rubisco, used to calculate Vcmax25, are determined by the LUNA model.

4. Water stress is applied using the hydraulic conductance model.

The article references the relevant technical note chapters that provide additional details on these updates, including the LUNA model (Chapter 2.10) and the plant hydraulics model (Chapter 2.11).