Conifer Needle Photosynthetic Performance at Niwot Ridge, 2017-2018

Niwot Ridge, Colorado, USA, is the location for this dataset of chlorophyll fluorescence measurements from pine and spruce needle tissues. It contains two specific pulse-amplitude-modulation (PAM) fluorometry metrics: the photosystem II (PSII) operating efficiency in light (Fq'/Fm') and the maximum quantum efficiency of PSII photochemistry (Fv/Fm) on dark-acclimated tissues. These measurements were collected during the summers of 2017 and 2018 to study the seasonality of photosynthetic performance at the needle level.

Use Cases

• Analyzing seasonal trends in photosynthetic efficiency based on Fq'/Fm' and Fv/Fm measurements.
• Comparing light-adapted versus dark-acclimated PSII performance in conifer species.
• Ground-truthing satellite-derived chlorophyll fluorescence data for a subalpine forest site.
• Modeling carbon uptake dynamics in pine and spruce ecosystems using needle-level physiological data.

Strengths

• Focuses on a specific, well-instrumented research site (Niwot Ridge AmeriFlux Core site US-NR1).
• Captures two distinct, standardized chlorophyll fluorescence metrics (Fq'/Fm' and Fv/Fm) over two summer field seasons.
• Hosted by a major scientific organization (National Aeronautics and Space Administration).

Limitations

• Column names and data structure are not described in the provided metadata.
• Conflicting 'last updated' dates (2018-06-11 vs. 2026-04-10) create uncertainty about metadata maintenance.
• The dataset's size, row count, and specific file formats within the ZIP archive are unknown.

Provenance

Source

National Aeronautics and Space Administration

Collection Method

Measurements made using pulse-amplitude-modulation (PAM) fluorometry on collected needle tissues.

Time Range

Summers of 2017 and 2018

Freshness

Last updated dates conflict: 2026-04-10 (datagov) and 2018-06-11 (nasa_earthdata).

Geography

Niwot Ridge AmeriFlux Core site (US-NR1) near Nederland, Colorado, USA