In Silviculturalist/forester: Forest Science and Forestry
knitr::opts_chunk$set(
collapse = TRUE,
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As part of the HUGIN project during the late 1970's and 1980's, Agestam presented in his seminal thesis a growth simulator for mixed stands of Pine, Spruce and Birch in Sweden [@agestam1985].
The HUGIN project included the following models for established stands (>>8m mean height), as presented by @ekö1985 pp. 9, table 1.
| Species | Type of model | Data | Reference |
|-----------------------------------------------------------------------------------------|--------------------|---------------------------------------|-----------------------|
| Scots Pine | Stand model | The Great Yield Investigation (1971). | |
| Norway Spruce | Stand model | The Great Yield Investigation (1971). | @eriksson1976 |
| Mixed stands of Pine, Spruce and Birch | Stand model | The Great Yield Investigation (1971). | @agestam1985 |
| Pure and mixed stands of pine, spruce, birch, beech, oak and other broad-leaved trees. | Single-tree model. | NFI | @söderberg1986 |
| Pure and mixed stands of pine, spruce, birch, beech, oak, and other broad-leaved trees. | Stand model | NFI | @ekö1985 |
| Lodgepole Pine | Stand model | Permanent plots | Hägglund et al (1979) |
: Growth simulators for established forests in the HUGIN-system.
These models followed a general sequence set up by @jonsson1980 .
-
Simulation of young stand and growth up to 8 metres.
-
A growth period increment length is chosen, c:a 5 years.
For every period.
i) Age is updated.
ii) Dominant height is calculated from trajectories, e.g.
The development of young stands is estimated by a separate model, e.g. @elfving1975 .
# ## Agestam production table 1.
# library(tidyverse)
# library(forester)
#
# #Start values.
# # Pure Pine stand, T20, total age 38, 2800 stems/ha. 23.8 m2/ha.
# stems <- 2800
# BA <- 23.8
# age <- 38
# SI_Pine <- 20
# increment_period <- 5
# latitude=64
#
# #age to breast height
# age_to_breast_height <- forester::Hagglund_age_to_height(latitude = latitude,
# SI = SI_Pine,
# dominant_height_m = 1.31,
# species = "Pinus sylvestris",
# regeneration = "culture")[[2]]
#
# age_at_breast_height <- age-age_to_breast_height
#
#
# ## Height equation
# dominant_height_m <- Hagglund_1974_Sweden_height_trajectories_Pine(age_at_breast_height = 100,
# top_height_dm = 200,
# regeneration ="culture",
# age_2 = age_at_breast_height,
# output = "Height")/10
#
# ## start volume
# volume <- Agestam_1985_volume_Pine_SI(basal_area_Pine_m2_ha = BA,
# SI_Pine_m = SI_Pine,
# age_at_breast_height_Pine = age_at_breast_height,
# stems_Pine_ha = stems,
# latitude = latitude)
#
#
# #start mean BA diam cm.
# mean_BA_diam_cm <- forester::basal_area_weighted_mean_diameter_cm(basal_area_m2_ha = BA,stem_count = stems)
#
# ## start thinning 40% BA above bark.
# BA_thinned <- BA*0.4
# stems_thinned <- BA_thinned/(pi*((mean_BA_diam_cm/2)/100)^2)
#
# BA <- BA-BA_thinned
# stems <- stems-stems_thinned
#
# #volume_after_thinning
# volume2 <- Agestam_1985_volume_Pine_SI(basal_area_Pine_m2_ha = BA,
# SI_Pine_m = SI_Pine,
# age_at_breast_height_Pine = age_at_breast_height,
# stems_Pine_ha = stems,
# latitude = latitude)
#
# #thinned_volume
# thinned_volume <- volume-volume2
#
# volume <- volume2
#
# output1 <- data.frame("age"=age,
# "age_brh"=age_at_breast_height,
# "dominant_height_m"=dominant_height_m,
# "stems"= stems,
# "stems_thinned"=stems_thinned,
# "thinned_volume"=thinned_volume,
# "BA_diam_cm_living"=mean_BA_diam_cm,
# "BA_diam_cm_self_thinned"=0,
# "BA"=BA,
# "volume"=volume,
# "mortality"=0)
#
#
# while(age_at_breast_height<=140){
#
# age_at_breast_height <- age_at_breast_height+increment_period
# age<- age+increment_period
#
# dominant_height_m <- Hagglund_1974_Sweden_height_trajectories_Pine(age_at_breast_height = 100,
# top_height_dm = SI_Pine*10,
# regeneration = "culture",
# age_2 = age_at_breast_height ,
# output = "Height")/10
#
# #Thinning
#
# #Default 0.
# stems_thinned <- 0
# thinned_volume <- 0
#
# if((age_at_breast_height-increment_period)<70 & age_at_breast_height>70){
# BA_thinned <- BA*0.35
# stems_thinned <- BA_thinned/(pi*((mean_BA_diam_cm/2)/100)^2)
#
# BA <- BA-BA_thinned
# stems <- stems-stems_thinned
#
# #volume_after_thinning
# volume2 <- Agestam_1985_volume_Pine_SI(basal_area_Pine_m2_ha = BA,
# SI_Pine_m = SI_Pine,
# age_at_breast_height_Pine = age_at_breast_height,
# stems_Pine_ha = stems,
# latitude = latitude)
#
# #thinned_volume
# thinned_volume <- volume-volume2
#
# volume <- volume2
# }
#
#
#
# #Estimate mortality
#
# #Mortality during period
# mortality_m2_ha <- Agestam_1985_mortality_above_bark_Pine(stems_Pine_ha = stems,
# basal_area_above_bark_all_species = BA,
# SI = SI_Pine,
# age_at_breast_height = age_at_breast_height)*increment_period
#
# mean_BA_diam_cm <- forester::basal_area_weighted_mean_diameter_cm(basal_area_m2_ha = BA,
# stem_count = stems)
# self_thinned_stem_diam_cm <- forester::Agestam_1985_mortality_diameter_cm(species = "Pinus sylvestris",
# age_at_breast_height = age_at_breast_height,
# basal_area_weighted_mean_diameter_cm_living = mean_BA_diam_cm)
#
# self_thinned_stems <- round(mortality_m2_ha/((pi*(self_thinned_stem_diam_cm/2)^2)/(100*100)),0)
#
# stems_thinned <- stems_thinned+self_thinned_stems
#
#
# #bark subtraction
# bark_period_start_m2_ha <- Agestam_1985_bark_subtraction_Pine(basal_area_over_bark_Pine = BA,
# SI_Pine = SI_Pine,
# latitude = latitude
# )
#
#
# BA_under_bark_period_start_m2_ha <- BA - bark_period_start_m2_ha
#
# #BA growth
# BA_growth_m2_ha <- Agestam_1985_basal_area_annual_increment_under_bark_Pine(basal_area_Pine_m2_ha_after_thinning = BA_under_bark_period_start_m2_ha,
# stem_count_Pine = stems,
# age_at_breast_height_period_start = age_at_breast_height,
# SI_H100_Pine = SI_Pine,
# basal_area_other_species_m2_ha_after_thinning = 0,
# diameter_mean_basal_area_stem_Pine_cm = forester::basal_area_weighted_mean_diameter_cm(basal_area_m2_ha = BA_under_bark_period_start_m2_ha,stem_count = stems),
# diameter_mean_basal_area_stem_all_species_cm = forester::basal_area_weighted_mean_diameter_cm(basal_area_m2_ha = BA_under_bark_period_start_m2_ha,stem_count = stems) ,
# increment_period_years = increment_period)*increment_period
#
# #Total after growth
# BA_after_growth_m2_ha <- BA_under_bark_period_start_m2_ha+BA_growth_m2_ha
#
# #Add bark
# BA_after_growth_m2_ha <- Agestam_1985_bark_addition_Pine(basal_area_under_bark_Pine = BA_after_growth_m2_ha,
# SI_Pine = SI_Pine,
# latitude = latitude)+BA_after_growth_m2_ha
#
#
# #final Basal Area
# BA <- BA_after_growth_m2_ha-mortality_m2_ha
#
# #new stem count
# stems <- stems-self_thinned_stems
#
# #Volume
# volume <- Agestam_1985_volume_Pine_SI(basal_area_Pine_m2_ha = BA,
# SI_Pine_m = SI_Pine,
# age_at_breast_height=age_at_breast_height,
# stems_Pine_ha = stems,
# latitude = latitude)
#
#
# output2 <- data.frame("age"=age,
# "age_brh"=age_at_breast_height,
# "dominant_height_m"=dominant_height_m,
# "stems"= stems,
# "stems_thinned"=stems_thinned,
# "thinned_volume"=thinned_volume,
# "BA_diam_cm_living"=mean_BA_diam_cm,
# "BA_diam_cm_self_thinned"=self_thinned_stem_diam_cm,
# "BA"=BA,
# "volume"=volume,
# "mortality"=mortality_m2_ha)
#
# output1 <- dplyr::bind_rows(output1,output2)
#
#
# }
#
# round(output1,1)
#
# #Correct values from production table 1, p. 86.
# correct <- data.frame("age_brh"=c(29,34,39,44,49,54,61,71,81,91,101,111,121,131,141),"volume"=c(69,87,107,130,153,177,212,175,216,261,306,352,397,442,486.5))
#
# #Plot results
# ggplot(output1,aes(x=age_brh,y=volume,linetype="own"))+geom_line()+geom_line(data=correct,aes(x=age_brh,y=volume,linetype="correct"))
Silviculturalist/forester documentation built on April 20, 2024, 2:13 p.m.
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knitr::opts_chunk$set( collapse = TRUE, comment = "#>" )
As part of the HUGIN project during the late 1970's and 1980's, Agestam presented in his seminal thesis a growth simulator for mixed stands of Pine, Spruce and Birch in Sweden [@agestam1985].
The HUGIN project included the following models for established stands (>>8m mean height), as presented by @ekö1985 pp. 9, table 1.
| Species | Type of model | Data | Reference | |-----------------------------------------------------------------------------------------|--------------------|---------------------------------------|-----------------------| | Scots Pine | Stand model | The Great Yield Investigation (1971). | | | Norway Spruce | Stand model | The Great Yield Investigation (1971). | @eriksson1976 | | Mixed stands of Pine, Spruce and Birch | Stand model | The Great Yield Investigation (1971). | @agestam1985 | | Pure and mixed stands of pine, spruce, birch, beech, oak and other broad-leaved trees. | Single-tree model. | NFI | @söderberg1986 | | Pure and mixed stands of pine, spruce, birch, beech, oak, and other broad-leaved trees. | Stand model | NFI | @ekö1985 | | Lodgepole Pine | Stand model | Permanent plots | Hägglund et al (1979) |
: Growth simulators for established forests in the HUGIN-system.
These models followed a general sequence set up by @jonsson1980 .
-
Simulation of young stand and growth up to 8 metres.
-
A growth period increment length is chosen, c:a 5 years.
For every period.
i) Age is updated.
ii) Dominant height is calculated from trajectories, e.g.
The development of young stands is estimated by a separate model, e.g. @elfving1975 .
# ## Agestam production table 1. # library(tidyverse) # library(forester) # # #Start values. # # Pure Pine stand, T20, total age 38, 2800 stems/ha. 23.8 m2/ha. # stems <- 2800 # BA <- 23.8 # age <- 38 # SI_Pine <- 20 # increment_period <- 5 # latitude=64 # # #age to breast height # age_to_breast_height <- forester::Hagglund_age_to_height(latitude = latitude, # SI = SI_Pine, # dominant_height_m = 1.31, # species = "Pinus sylvestris", # regeneration = "culture")[[2]] # # age_at_breast_height <- age-age_to_breast_height # # # ## Height equation # dominant_height_m <- Hagglund_1974_Sweden_height_trajectories_Pine(age_at_breast_height = 100, # top_height_dm = 200, # regeneration ="culture", # age_2 = age_at_breast_height, # output = "Height")/10 # # ## start volume # volume <- Agestam_1985_volume_Pine_SI(basal_area_Pine_m2_ha = BA, # SI_Pine_m = SI_Pine, # age_at_breast_height_Pine = age_at_breast_height, # stems_Pine_ha = stems, # latitude = latitude) # # # #start mean BA diam cm. # mean_BA_diam_cm <- forester::basal_area_weighted_mean_diameter_cm(basal_area_m2_ha = BA,stem_count = stems) # # ## start thinning 40% BA above bark. # BA_thinned <- BA*0.4 # stems_thinned <- BA_thinned/(pi*((mean_BA_diam_cm/2)/100)^2) # # BA <- BA-BA_thinned # stems <- stems-stems_thinned # # #volume_after_thinning # volume2 <- Agestam_1985_volume_Pine_SI(basal_area_Pine_m2_ha = BA, # SI_Pine_m = SI_Pine, # age_at_breast_height_Pine = age_at_breast_height, # stems_Pine_ha = stems, # latitude = latitude) # # #thinned_volume # thinned_volume <- volume-volume2 # # volume <- volume2 # # output1 <- data.frame("age"=age, # "age_brh"=age_at_breast_height, # "dominant_height_m"=dominant_height_m, # "stems"= stems, # "stems_thinned"=stems_thinned, # "thinned_volume"=thinned_volume, # "BA_diam_cm_living"=mean_BA_diam_cm, # "BA_diam_cm_self_thinned"=0, # "BA"=BA, # "volume"=volume, # "mortality"=0) # # # while(age_at_breast_height<=140){ # # age_at_breast_height <- age_at_breast_height+increment_period # age<- age+increment_period # # dominant_height_m <- Hagglund_1974_Sweden_height_trajectories_Pine(age_at_breast_height = 100, # top_height_dm = SI_Pine*10, # regeneration = "culture", # age_2 = age_at_breast_height , # output = "Height")/10 # # #Thinning # # #Default 0. # stems_thinned <- 0 # thinned_volume <- 0 # # if((age_at_breast_height-increment_period)<70 & age_at_breast_height>70){ # BA_thinned <- BA*0.35 # stems_thinned <- BA_thinned/(pi*((mean_BA_diam_cm/2)/100)^2) # # BA <- BA-BA_thinned # stems <- stems-stems_thinned # # #volume_after_thinning # volume2 <- Agestam_1985_volume_Pine_SI(basal_area_Pine_m2_ha = BA, # SI_Pine_m = SI_Pine, # age_at_breast_height_Pine = age_at_breast_height, # stems_Pine_ha = stems, # latitude = latitude) # # #thinned_volume # thinned_volume <- volume-volume2 # # volume <- volume2 # } # # # # #Estimate mortality # # #Mortality during period # mortality_m2_ha <- Agestam_1985_mortality_above_bark_Pine(stems_Pine_ha = stems, # basal_area_above_bark_all_species = BA, # SI = SI_Pine, # age_at_breast_height = age_at_breast_height)*increment_period # # mean_BA_diam_cm <- forester::basal_area_weighted_mean_diameter_cm(basal_area_m2_ha = BA, # stem_count = stems) # self_thinned_stem_diam_cm <- forester::Agestam_1985_mortality_diameter_cm(species = "Pinus sylvestris", # age_at_breast_height = age_at_breast_height, # basal_area_weighted_mean_diameter_cm_living = mean_BA_diam_cm) # # self_thinned_stems <- round(mortality_m2_ha/((pi*(self_thinned_stem_diam_cm/2)^2)/(100*100)),0) # # stems_thinned <- stems_thinned+self_thinned_stems # # # #bark subtraction # bark_period_start_m2_ha <- Agestam_1985_bark_subtraction_Pine(basal_area_over_bark_Pine = BA, # SI_Pine = SI_Pine, # latitude = latitude # ) # # # BA_under_bark_period_start_m2_ha <- BA - bark_period_start_m2_ha # # #BA growth # BA_growth_m2_ha <- Agestam_1985_basal_area_annual_increment_under_bark_Pine(basal_area_Pine_m2_ha_after_thinning = BA_under_bark_period_start_m2_ha, # stem_count_Pine = stems, # age_at_breast_height_period_start = age_at_breast_height, # SI_H100_Pine = SI_Pine, # basal_area_other_species_m2_ha_after_thinning = 0, # diameter_mean_basal_area_stem_Pine_cm = forester::basal_area_weighted_mean_diameter_cm(basal_area_m2_ha = BA_under_bark_period_start_m2_ha,stem_count = stems), # diameter_mean_basal_area_stem_all_species_cm = forester::basal_area_weighted_mean_diameter_cm(basal_area_m2_ha = BA_under_bark_period_start_m2_ha,stem_count = stems) , # increment_period_years = increment_period)*increment_period # # #Total after growth # BA_after_growth_m2_ha <- BA_under_bark_period_start_m2_ha+BA_growth_m2_ha # # #Add bark # BA_after_growth_m2_ha <- Agestam_1985_bark_addition_Pine(basal_area_under_bark_Pine = BA_after_growth_m2_ha, # SI_Pine = SI_Pine, # latitude = latitude)+BA_after_growth_m2_ha # # # #final Basal Area # BA <- BA_after_growth_m2_ha-mortality_m2_ha # # #new stem count # stems <- stems-self_thinned_stems # # #Volume # volume <- Agestam_1985_volume_Pine_SI(basal_area_Pine_m2_ha = BA, # SI_Pine_m = SI_Pine, # age_at_breast_height=age_at_breast_height, # stems_Pine_ha = stems, # latitude = latitude) # # # output2 <- data.frame("age"=age, # "age_brh"=age_at_breast_height, # "dominant_height_m"=dominant_height_m, # "stems"= stems, # "stems_thinned"=stems_thinned, # "thinned_volume"=thinned_volume, # "BA_diam_cm_living"=mean_BA_diam_cm, # "BA_diam_cm_self_thinned"=self_thinned_stem_diam_cm, # "BA"=BA, # "volume"=volume, # "mortality"=mortality_m2_ha) # # output1 <- dplyr::bind_rows(output1,output2) # # # } # # round(output1,1) # # #Correct values from production table 1, p. 86. # correct <- data.frame("age_brh"=c(29,34,39,44,49,54,61,71,81,91,101,111,121,131,141),"volume"=c(69,87,107,130,153,177,212,175,216,261,306,352,397,442,486.5)) # # #Plot results # ggplot(output1,aes(x=age_brh,y=volume,linetype="own"))+geom_line()+geom_line(data=correct,aes(x=age_brh,y=volume,linetype="correct"))
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