sprucesim: Stand Level Forest Growth and Yield Simulator

In mickyallen10/sprucesim: Stand Level Forest Growth and Yield Simulator for Norway Spruce

Stand Level Forest Growth and Yield Simulator

Description

Simulates stand level forest growth and yield for Norway spruce forests, includining thinning treatments.

Usage

sprucesim(stand.df, functions, n.periods = 5, period.length, print.comments = F, domsi = F, thin = F, num.thins = NULL, thin.bph = T, thinbyperc = F, min.bph.thin1 = NULL, min.bph.thin2 = NULL, min.hd.thin1 = NULL, min.hd.thin2 = NULL, bph.after.thin1 = NULL, bph.after.thin2 = NULL, bph.tq1 = NULL, bph.tq2 = NULL, ...)

Arguments

stand.df	A data frame of stand level values.
functions	List of functions for simulating forest growth and yeild must be specified. Functions needed are: fn.domht (Dominant height growth function), fn.survival (survival function), fn.basalarea (basal area growth function), fn.qmd (quadratic mean diameter calculation), fn.vol (volume estimation function), fn.treerem (function for calculating the number of trees per hectare after thinning).
n.periods	Integer value of the number of periods simulated.
period.length	Length of each growth period. Defaults to 5 (the recomended period length).
print.comments
domsi	Logical value. If dominant stand height is to be predicted from Site Index. Defaults to FALSE.
thin	Logical value. Specify if thinning should be implemented.
num.thins	Integer value. Specify the number of thins that will be implemented. Currently only accepts values of 1 or 2.
thin.bph	Logical value. Specify if the timing of thinning should determined by a set basal area.
thinbyperc	Logical value. Specify how thinning should be performed. If False, then a minimum residual basal area after thinning (min.bph.thin1 or min.bph.thin2) must be specified. If True, then the percent of basal area remaining after thinning must be specified (bph.tq1 or bph.tq2).
min.bph.thin1	If num.thins == (1 | 2) & thinbyperc == F, then specify the residual basal area per hectare (m2) following thinning.
min.bph.thin2	If num.thins == 2 & thinbyperc == F, then specify the residual basal area per hectare (m2) following the second thinning.
min.hd.thin1	If thin.bph == F and num.thins == (1 | 2), then specify the dominant height (m) at which the stand should be thinned.
min.hd.thin2	If thin.bph == F and num.thins == 2, then specify the dominant height (m) at the second thinning.
bph.after.thin1	if thinbyperc == F and num.thins == (1 | 2), then specify the residual basal area after the first thinning.
bph.after.thin2	If thinbyperc == F and num.thins == 2, then specify the residual basal area after the second thinning.
bph.tq1	If thinbyperc == T and num.thins in (1 | 2), then specify the percentage residual basal area after first thin (value between 0 and 1).
bph.tq2	If thinbyperc == T and num.thins == 2, then specify the percentage residual basal area after second thin (value between 0 and 1).
...	other values that may be passed.

Details

The data.frame stand.df should include columns for: plot.id (an ID for the stand/plots to be simulated), age (stand age from planting in years), tph (the number of trees per hectare), bph (basal are per hectare in m2), qmd (stand quadratic mean diameter in cm), hd (stand dominant height in m), si (site index in m), vol (stand volume per hectare in m3), and thinid = (0 for unthinned and 1 for thinned).

Value

Returns a LIST named "fl" which has the following components for each simulation period:

plot.id	<unique plot.id supplied in stand.df
age	stand age (years)
tph	number of trees per hectare
tpha	number of trees per hectare after thinning
tphb	number of trees per hectare before thinning
bph	basal area per hectare (m2)
bpha	basal area per hectare (m2) after thinning
bphb	basal area per hectare (m2) before thinning
bphr	basal area per hectare (m2) removed in thinning
qmd	quadratic mean diameter (cm)
qmda	quadratic mean diameter (cm) after thinning
qmdb	quadratic mean diameter (cm) before thinnig
hd	dominant stand height (m)
tage	stand age at time of thinning
hd_thin	Dominant stand height (m) at time of thinning
si	site index (m) at base age 40 years
thinid	ID for if a stand is thinned (1) or not thinned (0)
vol	stand volume per hectare (m3)
vola	stand volume per hectare (m3) before thinning
volb	stand volume per hectare (m3) after thinning
volr	stand volume per hectare (m3) removed in thinning

Note

In addition, if initial stands/plots are thinned, columns for thinning values should be provided. These variables are: tpha, bpha, qmda, vola (trees per hectare, basal area per hectare, quadratic mean diameter, and volume per hectare "after" thinning); tphb, bphb, qmdb, volb (trees per hectare, basal area per hectare, quatratic mean diameter, and volume per hectare "before thinning"; bphr and volr (basal area per hectare and volume per hectare "removed" in thinning); tage (stand age at thinning), hd_thin (dominant stand height at thinning))

Author(s)

Micky G Allen II <[e-mail]>

Examples

#Simulate G&Y without thinning
sprucesim(stand.df = SpruceStands,
         period.length=5,
n.periods = 20,
functions = list(
fn.basalarea = basal_area,
fn.domht = dom_height,
fn.survival = survival,
fn.qmd = qmd,
fn.treerem = tree_reduction,
fn.vol = volume),

thin=FALSE,
num.thins = NULL,

thin.bph = TRUE,
thinbyperc=FALSE,

min.bph.thin1 = NULL,
min.bph.thin2 = NULL,

min.hd.thin1 = NULL,
min.hd.thin2 = NULL,

bph.after.thin1 = NULL,
bph.after.thin2 = NULL,

bph.tq1 = NULL,
bph.tq2 = NULL)


#Thin 1 time removing 25% basal area
#Thin when stand basal area reaches 24 m2
sprucesim(stand.df = SpruceStands,
                 period.length=5,
                 n.periods = 20,
                 functions = list(
                   fn.basalarea = basal_area,
                   fn.domht = dom_height,
                   fn.survival = survival,
                   fn.qmd = qmd,
                   fn.treerem = tree_reduction,
                   fn.vol = volume),

                 thin=TRUE,
                 num.thins = 1,

                 thin.bph = TRUE,
                 thinbyperc=TRUE,

                 min.bph.thin1 = 24,
                 min.bph.thin2 = NULL,

                 min.hd.thin1 = NULL,
                 min.hd.thin2 = NULL,

                 bph.after.thin1 = NULL,
                 bph.after.thin2 = NULL,

                 bph.tq1 = 0.8,
                 bph.tq2 = NULL)

#Thin 1 time removing 25% basal area
#Thin when stand dominant height is 12m
sprucesim(stand.df = SpruceStands,
         period.length=5,
         n.periods = 20,
         functions = list(
           fn.basalarea = basal_area,
           fn.domht = dom_height,
           fn.survival = survival,
           fn.qmd = qmd,
           fn.treerem = tree_reduction,
           fn.vol = volume),

         thin=TRUE,
         num.thins = 1,

         thin.bph = FALSE,
         thinbyperc=TRUE,

         min.bph.thin1 = NULL,
         min.bph.thin2 = NULL,

         min.hd.thin1 = 12,
         min.hd.thin2 = NULL,

         bph.after.thin1 = NULL,
         bph.after.thin2 = NULL,

         bph.tq1 = 0.8,
         bph.tq2 = NULL)
         

mickyallen10/sprucesim documentation built on May 10, 2023, 6:17 a.m.