Chilling_Hours {chillR} | R Documentation |
Calculation of cumulative chill according to the Chilling Hours Model
Description
This function calculates winter chill for temperate trees according to the Chilling Hours Model.
Usage
Chilling_Hours(HourTemp, summ = TRUE)
Arguments
HourTemp |
Vector of hourly temperatures. |
summ |
Boolean parameter indicating whether calculated metrics should be provided as cumulative values over the entire record (TRUE) or as the actual accumulation for each hour (FALSE). |
Details
Chilling Hours are calculated as suggested by Bennett (1949) (all hours with temperatures between 0 and 7.2 degrees C are considered as one Chilling Hour.
Value
Vector of length length(HourTemp) containing the cumulative Chilling Hours over the entire duration of HourTemp.
Note
After doing extensive model comparisons, and reviewing a lot of relevant literature, I do not recommend using the Chilling Hours, especially in warm climates! The Dynamic Model (Chill Portions), though far from perfect, seems much more reliable.
Author(s)
Eike Luedeling
References
Chilling Hours references:
Weinberger JH (1950) Chilling requirements of peach varieties. Proc Am Soc Hortic Sci 56, 122-128
Bennett JP (1949) Temperature and bud rest period. Calif Agric 3 (11), 9+12
Examples
weather<-fix_weather(KA_weather[which(KA_weather$Year>2006),])
hourtemps<-stack_hourly_temps(weather,latitude=50.4)
Chilling_Hours(hourtemps$hourtemps$Temp)