Soderberg1986formfactor: Form factor for Individual trees in Sweden from Söderberg...

In Silviculturalist/forester: Forest Science and Forestry

Form factor for Individual trees in Sweden from Söderberg 1986.

Description

Applicable counties:

Northern Sweden
	Norrbottens lappmark
	Norrbottens kustland
	Västerbottens lappmark
	Västerbottens kustland
	Västernorrland - Ångermanlands landskap
	Västernorrland - Medelpads landskap
	Jämtland - Jämtlands landskap
	Jämtland - Härjedalens landskap
	Kopparberg - Sälen-Idre.
Central Sweden
	Kopparberg - övriga
	Gävleborg - Hälsinglands landskap
	Gävleborg - övriga
	Värmland
Southern Sweden
	Stockholm
	Uppsala
	Västmanland
	Södermanland
	Örebro
	Östergötland
	Skaraborg
	Älvsborg - Västergötlands landskap
	Älvsborg - Dalslands landskap
	Jönköping
	Kronoberg
	Kalmar
	Halland
	Kristianstad
	Malmöhus
	Blekinge
	Gotland

Regarding the regional division of the models:

Freely translated from Söderberg 1986 p. 29: 'The regional division is motivated in the following. For Pine the country has been divided into 3 regions (see figure 4.1), which are based on the different forms of Scots Pine which have been distinguished by Sylvén 1917. The distribution of the different forms of Scots Pine is assumed to depend on the expansion-history of the Pine, according to which the Pine immigrated both from the north and the south with a transitional zone in central Sweden, where both forms are present. For other species, the change in genotype is more continuous over the country (Kiellander 1974). For Norway Spruce, it is assumed that it has had time for 30-50 generations in northern Sweden, contrasted against only 10-20 in southern Sweden (Kiellander 1966). Therefore the same regional division is used for Norway Spruce as for Scots Pine. For the other species, the regional division is limited to two regions, wherein the northern and central regions have been merged.

NB in Söderberg (1986), no correction for logarithmic bias was introduced , as, (freely translated) p. 114: "At the presentation of the functions we lightly touched on the effects of the measurement errors in the variables which had been included in the regression. It was then concluded that several factors contrived to that the spread about the functions is overestimated. Therefore no correction for logarithmic bias was carried out, primarily because the effect of the errors in the indipendent variables on the spread about the function are difficult to establish. If one were to assume that the spread about the function was overestimated by 10 percent, the predicted growth from the functions would be increased by roughly 2 percent. For 20 percents overestimation, an increase of predicted growth by 4.5 percent."

Usage

Soderberg_1986_form_factor_Sweden_Oak(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  BA_Beech.m2_ha,
  BA_Birch.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  age,
  vegetation,
  soil_moisture,
  lateral_water,
  altitude,
  divided_plot = 0,
  county
)

Soderberg_1986_form_factor_Sweden_Beech(
  DBH.cm,
  BA_Beech.m2_ha,
  BA_Oak.m2_ha,
  BA.m2_ha,
  SI100_Spruce,
  age,
  aspect,
  altitude,
  divided_plot = 0
)

Soderberg_1986_form_factor_southern_Sweden_Spruce(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  continental,
  maritime,
  BA_Spruce.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  age,
  aspect,
  latitude,
  altitude,
  lateral_water,
  divided_plot = 0,
  county
)

Soderberg_1986_form_factor_southern_Sweden_Pine(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  distance_to_coast_km,
  BA_Spruce.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  vegetation,
  age,
  latitude,
  altitude,
  county,
  maritime,
  soil_moisture,
  divided_plot = 0,
  fertilised_plot
)

Soderberg_1986_form_factor_southern_Sweden_Broadleaves(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  BA_Spruce.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  age,
  latitude,
  vegetation,
  soil_moisture,
  aspect,
  divided_plot = 0
)

Soderberg_1986_form_factor_southern_Sweden_Birch(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  maritime,
  BA_Birch.m2_ha,
  BA_Pine.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  vegetation,
  age,
  latitude,
  altitude,
  divided_plot = 0,
  fertilised_plot = 0,
  county
)

Soderberg_1986_form_factor_northern_Sweden_Pine(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  distance_to_coast_km,
  BA_Pine.m2_ha,
  BA_Spruce.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  vegetation,
  age,
  latitude,
  altitude,
  aspect,
  soil_moisture,
  divided_plot = 0
)

Soderberg_1986_form_factor_northern_central_Sweden_Spruce(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  distance_to_coast_km,
  continental,
  BA_Spruce.m2_ha,
  BA_Pine.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  vegetation,
  age,
  aspect,
  latitude,
  altitude,
  soil_moisture,
  lateral_water,
  divided_plot = 0
)

Soderberg_1986_form_factor_northern_central_Sweden_Broadleaves(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  maritime,
  BA_Spruce.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  age,
  latitude,
  altitude,
  lateral_water,
  divided_plot = 0
)

Soderberg_1986_form_factor_northern_central_Sweden_Birch(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  BA_Spruce.m2_ha,
  BA_Pine.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  vegetation,
  aspect,
  age,
  latitude,
  altitude,
  soil_moisture,
  lateral_water,
  fertilised_plot,
  divided_plot = 0
)

Soderberg_1986_form_factor_Gotland_Sweden_Pine(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  BA_Pine.m2_ha,
  BA.m2_ha,
  SI100_Spruce,
  age,
  altitude,
  divided_plot = 0
)

Soderberg_1986_form_factor_central_Sweden_Pine(
  DBH.cm,
  DBH_largest_tree_on_plot.cm,
  distance_to_coast_km,
  BA_Pine.m2_ha,
  BA.m2_ha,
  SI_species,
  SI100,
  age,
  latitude,
  altitude,
  soil_moisture,
  fertilised_plot,
  divided_plot = 0
)

Arguments

DBH.cm	Diameter at breast height
DBH_largest_tree_on_plot.cm	Diameter at breast height of the largest tree on the plot.
BA_Beech.m2_ha	Basal area Beech on the plot, m^2 / ha.
BA_Birch.m2_ha	Basal area Birch on the plot, m^2 / ha.
BA.m2_ha	Basal area of all tree species the plot, m^2 / ha.
SI_species	Species for which SIH100 was estimated. One of : 'Picea abies' or 'Pinus sylvestris'.
SI100	Site Index H100, m.
age	Age at breast height of the tree.
vegetation	1-18. See Sweden_vegetation_types() for description.
soil_moisture	1-5. e.g. Sweden_soil_types()
lateral_water	Code Description 1 Missing 2 Seldom 3 Shorter periods 4 Longer periods 5 Slope
altitude	Altitude, meters above sea level.
divided_plot	1 for plots described in different parts, which appears when the original plot consists of different land classes, density classes or cutting classes or belongs to different owners. 0 for full plots (default).
county	Character string. One of: Northern Sweden Norrbottens lappmark Norrbottens kustland Västerbottens lappmark Västerbottens kustland Västernorrland - Ångermanlands landskap Västernorrland - Medelpads landskap Jämtland - Jämtlands landskap Jämtland - Härjedalens landskap Kopparberg - Sälen-Idre. Central Sweden Kopparberg - övriga Gävleborg - Hälsinglands landskap Gävleborg - övriga Värmland Southern Sweden Stockholm Uppsala Västmanland Södermanland Örebro Östergötland Skaraborg Älvsborg - Västergötlands landskap Älvsborg - Dalslands landskap Jönköping Kronoberg Kalmar Halland Kristianstad Malmöhus Blekinge Gotland
BA_Oak.m2_ha	Basal area Oak on the plot, m^2 / ha.
SI100_Spruce	Site Index H100, m for Norway Spruce. See description.#'
aspect	If more than 2:20 / 5\ 1 North 2 North-East 3 East 4 South-East 5 South 6 South-West 7 West 8 North-West
continental	TRUE, if the plot is situated in a continental climatic region. cf. Ångstrom 1958. e.g. Angstrom_1958_local_climate_Sweden() . Otherwise FALSE.
maritime	TRUE, if the plot is situated in a maritime climatic region. cf. Ångstrom 1958. e.g. Angstrom_1958_local_climate_Sweden() . Otherwise FALSE.
BA_Spruce.m2_ha	Basal area Norway Spruce on the plot, m^2 / ha.
latitude	Latitude, degrees.
distance_to_coast_km	Closest distance to coast, in km, e.g. coast_distance
fertilised_plot	1 for fertilised plots, 0 for others (default).
BA_Pine.m2_ha	Basal area Scots Pine on the plot, m^2 / ha.

Details

Oak

OBSERVE: The function has a typo in the book. Although the variable description states that it is Altitude, the symbol shows LAT. I have interpreted this as that it should be Altitude, since the size of the coefficient is most alike coefficients for ALT in other related functions.

Multiple correlation coefficient R	0.86
Spread about the function sf	0.180
sf/Spread about the mean	0.516
Number of observations	292

Beech

OBSERVE: The function has a typo in the book. Although the variable description states that it is Altitude^2, the symbol shows LAT^2. I have interpreted this as that it should be Altitude^2, since the size of the coefficient is most alike coefficients for ALT^2 in other related functions.

OBSERVE: The following interpretation was made of the function - since only a factor was given for the Site Index in the case that the indicating species was Picea abies, this was interpreted as mandatory. Therefore, SI_Species and SI100 have been replaced by SI100_Spruce.

Multiple correlation coefficient R	0.90
Spread about the function sf	0.165
sf/Spread about the mean	0.442
Number of observations	219

Norway Spruce in southern Sweden

OBSERVE: As per p. 64 , if county is equal to "Gotland": "Residual studies for these species indicate the functions for the mainland (Spruce south, Birch south) can be used with a reduction of the constant term amounting to -0.089 and -0.067, respectively".

Multiple correlation coefficient R	0.94
Spread about the function sf	0.128
sf/Spread about the mean	0.346
Number of observations	7311

Norway Spruce in Central or Northern Sweden

Multiple correlation coefficient R	0.93
Spread about the function sf	0.132
sf/Spread about the mean	0.365
Number of observations	7410

Scots Pine in Northern Sweden

Multiple correlation coefficient R	0.94
Spread about the function sf	0.107
sf/Spread about the mean	0.352
Number of observations	3785

Scots Pine in Central Sweden

Multiple correlation coefficient R	0.94
Spread about the function sf	0.105
sf/Spread about the mean	0.328
Number of observations	2248

Scots Pine in southern Sweden

NB for the island of Gotland, use Soderberg_1986_form_factor_Gotland_Sweden_Pine()

Multiple correlation coefficient R	0.92
Spread about the function sf	0.120
sf/Spread about the mean	0.395
Number of observations	4231

Scots Pine on the island Gotland

Multiple correlation coefficient R	0.84
Spread about the function sf	0.150
sf/Spread about the mean	0.545
Number of observations	351

Broadleaves in southern Sweden

Multiple correlation coefficient R	0.80
Spread about the function sf	0.187
sf/Spread about the mean	0.609
Number of observations	831

Broadleaves in Central or Northern Sweden

Multiple correlation coefficient R	0.87
Spread about the function sf	0.174
sf/Spread about the mean	0.499
Number of observations	317

Birch in southern Sweden

OBSERVE: As per p. 64 , if county is equal to "Gotland": "Residual studies for these species indicate the functions for the mainland (Spruce south, Birch south) can be used with a reduction of the constant term amounting to -0.089 and -0.067, respectively".

Multiple correlation coefficient R	0.85
Spread about the function sf	0.161
sf/Spread about the mean	0.533
Number of observations	1725

Birch in Central or Northern Sweden

Multiple correlation coefficient R	0.91
Spread about the function sf	0.138
sf/Spread about the mean	0.416
Number of observations	1735

Value

Form quotient of tree

Source

Söderberg, U. (1986) Funktioner för skogliga produktionsprognoser - Tillväxt och formhöjd för enskilda träd av inhemska trädslag i Sverige. / Functions for forecasting of timber yields - Increment and form height for individual trees of native species in Sweden. Report 14. Section of Forest Mensuration and Management. Swedish University of Agricultural Sciences. Umeå. ISBN 91-576-2634-0. ISSN 0349-2133. pp.251.

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