Hagglund_1974_Sweden_height_trajectories_Pine: Hägglund 1974 Height growth of Scots Pine in Sweden.

In Silviculturalist/forester: Forest Science and Forestry

Hägglund 1974 Height growth of Scots Pine in Sweden.

Description

Largely based on the Fortran IV script appended to the original source. Does not include certain functions to calculate if age at breast height is unknown, and has been adapted to R such that it will return one value at a time rather than print a matrix for height developments.

Usage

Hagglund_1974_Sweden_height_trajectories_Pine(
  dominant_height,
  age,
  age2,
  regeneration = "culture",
  output = "Height"
)

Arguments

dominant_height	Top height of tree or stand in m.
age	Age of stand or tree at breast height 1.3 m.
age2	Necessary if output is "Height". The age for which height along the same curve is to be computed.
regeneration	How was the stand established? One of "culture", "natural" or "unknown".
output	One of "Height" (default), "SIH100", or "Equation".

Details

OBSERVE! Will throw warnings if outside of material, but not stop.

Based on the Chapman-Richards function. f.4.1

OBSERVE! The SIH100 returned is H100 TOTAL AGE, whereas if you enter age2 as 100 and output == "Height", it is age at breast height. Example below analogous from Spruce. In order to calculate Height at another point in time (age2 at breast height) based on a SIH100 total age (age1 total age) - subtract the time to breast height from age1. e.g. From Total Age 100, H=16 to age at breast height age2. Hagglund_1972_northern_Sweden_Height_trajectories_Spruce(16,age=100-forester::Hagglund_1972_Norway_Spruce_time_to_BH_northern_Sweden(16,1,61),age2=140,61,1)

Value

If output is "SIH100", the numeric value for the height (m) a stand will reach at age 100.

If output is "Height", the numeric value for the height (m) a stand will reach at age2.

If output is "Equation", a named list with 2 elements: I) "Equation": text response with the equation for that height curve. II) "T13": The time taken to reach breast height 1.3m.

Source

Hägglund, Björn (1974) Övre höjdens utveckling i tallbestånd: Site index curves for Scots Pine in Sweden. Dept. of Forest Yield Research. Royal College of Forestry. Report 31. 54 pp. Stockholm.

See Also

[forester::Hagglund_1974_Sweden_Time_to_Breast_Height_Pine]

Examples

ggplot()+
scale_x_continuous(limits = c(0,120),expand = c(0,0))+
scale_y_continuous(limits=c(0,27),expand = c(0,0))+
#expand_limits(x=c(0,130),y=c(0,30))+
geom_function(aes(linetype="a"), fun = function (age)
 #20
 (13+233.564868164063*(1-exp(-age*0.0172925395397362))^1.14013833378919)/10
)+
geom_function(aes(linetype="b"), fun = function(age)

 #22
 (13+248.657690429688*(1-exp(-age*0.0188389760256776))^1.12794900485356)/10

)+

geom_function(aes(linetype="c"), fun= function(age)

 #24
 (13+264.911499023438*(1-exp(-age*0.0205442213276424))^1.11788897659132)/10

)+

geom_function(aes(linetype="d"), fun= function(age)

  #16
  (13+203.379223632813*(1-exp(-age*0.0143125270333732))^1.17804835993454)/10

)+
theme_classic()+
theme(plot.title = element_text(face="italic",family="serif"),
      plot.margin = unit(c(10,20,10,10), units="points"),
      legend.position = "none")+
labs(
  title="Development of Dominant height of\nScots pine in Sweden",
  caption="After Hägglund (1974) f. 4.1.",
  x="Age at breast height (years)",
  y="Dominant Height (m)"
)+
annotate("text",x=115, y=26,label="24",size=3)+
annotate("text",x=115, y=24, label="22", size=3)+
annotate("text",x=115, y=22, label="20",size=3)+
annotate("text",x=115, y=18, label="16",size=3)

Silviculturalist/forester documentation built on April 20, 2024, 2:13 p.m.