chillR

Statistical Methods for Phenology Analysis in Temperate Fruit Trees

The phenology of plants (i.e. the timing of their annual life phases) depends on climatic cues. For temperate trees and many other plants, spring phases, such as leaf emergence and flowering, have been found to result from the effects of both cool (chilling) conditions and heat. Fruit tree scientists (pomologists) have developed some metrics to quantify chilling and heat (e.g. see Luedeling (2012) <doi.org/10.1016/j.scienta.2012.07.011>). 'chillR' contains functions for processing temperature records into chilling (Chilling Hours, Utah Chill Units and Chill Portions) and heat units (Growing Degree Hours). Regarding chilling metrics, Chill Portions are often considered the most promising, but they are difficult to calculate. This package makes it easy. 'chillR' also contains procedures for conducting a PLS analysis relating phenological dates (e.g. bloom dates) to either mean temperatures or mean chill and heat accumulation rates, based on long-term weather and phenology records (Luedeling and Gassner (2012) <doi.org/10.1016/j.agrformet.2011.10.020>). As of version 0.65, it also includes functions for generating weather scenarios with a weather generator, for conducting climate change analyses for temperature-based climatic metrics and for plotting results from such analyses. Since version 0.70, 'chillR' contains a function for interpolating hourly temperature records.

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Description file content

Package
chillR
Type
Package
Title
Statistical Methods for Phenology Analysis in Temperate Fruit Trees
Version
0.70.21
Date
2019-11-05
Author
Eike Luedeling
Maintainer
Eike Luedeling
Description
The phenology of plants (i.e. the timing of their annual life phases) depends on climatic cues. For temperate trees and many other plants, spring phases, such as leaf emergence and flowering, have been found to result from the effects of both cool (chilling) conditions and heat. Fruit tree scientists (pomologists) have developed some metrics to quantify chilling and heat (e.g. see Luedeling (2012) ). 'chillR' contains functions for processing temperature records into chilling (Chilling Hours, Utah Chill Units and Chill Portions) and heat units (Growing Degree Hours). Regarding chilling metrics, Chill Portions are often considered the most promising, but they are difficult to calculate. This package makes it easy. 'chillR' also contains procedures for conducting a PLS analysis relating phenological dates (e.g. bloom dates) to either mean temperatures or mean chill and heat accumulation rates, based on long-term weather and phenology records (Luedeling and Gassner (2012) ). As of version 0.65, it also includes functions for generating weather scenarios with a weather generator, for conducting climate change analyses for temperature-based climatic metrics and for plotting results from such analyses. Since version 0.70, 'chillR' contains a function for interpolating hourly temperature records.
Depends
R (>= 3.2.0)
Imports
pls, dplyr, rlang, Kendall, fields, sp, readxl, XML, httr, grDevices, graphics, jsonlite, stats, utils, RMAWGEN, RCurl, R.utils, raster, ggplot2, assertthat, reshape2, plyr
Suggests
knitr, rmarkdown
VignetteBuilder
knitr
License
GPL-3
LazyData
TRUE
RoxygenNote
6.1.1
Encoding
UTF-8
NeedsCompilation
no
Packaged
2019-11-05 20:39:18 UTC; EL
Repository
CRAN
Date/Publication
2019-11-05 21:20:03 UTC

install.packages('chillR')

0.70.21

10 days ago

Eike Luedeling

GPL-3

Depends on

R (>= 3.2.0)

Imports

pls, dplyr, rlang, Kendall, fields, sp, readxl, XML, httr, grDevices, graphics, jsonlite, stats, utils, RMAWGEN, RCurl, R.utils, raster, ggplot2, assertthat, reshape2, plyr

Suggests

knitr, rmarkdown

Discussions