Data from: Flowering and flower maturation in valley oak Quercus lobata
Data files
Jun 01, 2026 version files 10.76 KB
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README.md
1.99 KB
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tree_data.csv
6.61 KB
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year_data.csv
2.16 KB
Abstract
We investigated factors driving flowering and flower maturation and their effects on acorn production at both the annual and individual tree levels in a population of valley oak (Quercus lobata) in central coastal California, USA. Over the years, female flower production was negatively correlated with rainfall, while warm spring temperatures and a large acorn crop the previous year decreased the proportion of flowers maturing into acorns. Among trees, individuals with greater access to groundwater growing in warmer microclimates produced more catkins and more female flowers. Among trees, male and female flower abundance were positively correlated even after controlling for tree size and resources, countering the hypothesis of a life-history tradeoff between investment in male and female flowering. Factors limiting pollen availability include weather-driven effects (both the pollination Moran effect and environmental vetos), phenological synchrony, and pollen coupling, factors that were difficult to distinguish. All three flower indices explained a significant proportion of variance in acorn production at both the annual and individual tree levels. Most important, however, was variation in female flower maturation, while both female and male flower abundance explained between one-quarter and one-third of the variance in acorn production. Q. lobata is not only a flower maturation masting species, but also a female flower and male flower masting species. The underlying drivers of flower initiation, fertilization, and flower maturation yield important insights into the factors influencing masting behavior in perennial plants and represent an area warranting more empirical study.
Dataset DOI: 10.5061/dryad.4qrfj6qst
Description of the data and file structure
There are two main data files, one for the annual data (year_data.csv) and one for the individual tree data (tree_data.csv). The path analyses used these files and the R program sem (package lavaan). Any NA represents missing data.
Files and variables
File: year_data.csv
Description:
Variables
- year: year
- xLN30: Mean overall acorn crop of all Q. lobata that year (ln-transformed mean number of acorns counted per 30 s visual sample; see text)
- xMAXCATKIN: Mean (maximum) catkin score that year (0 to 3; see text)
- xflowperleaf: Mean number of female flowers per 100 leaves
- xacperflow: Mean number of acorns per 100 leaves
- winrain: Winter rainfall (cm)
- taprave: Mean April temperature that year (degrees C)
- xLN30m1: Mean overall acorn crop of Q. lobata lagged one year (see xLN30)
File: tree_data.csv
Description:
Variables
- ID: Tree ID
- xLN30: Mean acorn crop for that tree, 1992 – 2025 (ln-transformed mean number of acorns counted per 30 s visual sample; see text)
- xMAXCATKIN: Mean (maximum) catkin score for that tree over all years (0 to 3; see text)
- xflowperleaf: Mean number of female flowers per 100 leaves for that tree
- xacperflow: Mean acorns per flower for that tree (maturation index)
- dbh: DBH of the tree in 2008 (cm)
- FoliarN: total Foliar nitrogen (% mass)
- FoliarP: total foliar phosphorus (% mass)
- XWP: Predawn xylem water potential (MPa)
- avewintemp: Mean winter temperature measured by the iButtons (degrees C)
- apravetemp: Mean April temperature measured by the iButtons (degrees C)
Code/software
Any program that will open a spreadsheet, such as Excel is recommended. RStudio (Software capable of running R, R version 4.4.2 ) is used for the data analysis.