woodValuationDE (version 1.0.2)

vol_skidded: Relative share in the volume over bark that is skidded

Description

The function estimates the skidded share of the wood volume. It is expressed in relation to the volume over bark (German unit: Vfm m.R.) as usually provided by yield tables and forest simulators. This includes all pulp wood and sawlog assortments. It is assumed that the fuel wood assortments are processed by buyers themselves and that they are thus not commercially delivered to the forest road. The share of salable wood is required to derive the costs for harvesting and skidding per cubic meter volume over bark. The function is based on the assortment tables from Offer and Staupendahl (2018) and its derivation is described in Fuchs et al. (2023). The underlying assortment tables are based on data from HessenForst, the public forest service of the Federal State of Hesse in Germany. For further details see the woodValuationDE README.

Usage

vol_skidded(
  diameter.q,
  species,
  value.level = 2,
  logging.method = "combined",
  species.code.type = "en",
  method = "fuchs.orig"
)

Value

A vector with relative shares of skidded wood volume.

Arguments

diameter.q

Quadratic mean of the diameter at breast height (dbh) of the harvested trees \([cm]\).

species

Tree species, using an available species.code.type. For a list with the available species and codes call get_species_codes.

value.level

Stand quality expressed as an integer of 1:3, with 1 for an extraordinarily high stand quality with high shares of wood suitable for high-valued usages such as furniture, 2 for a moderate quality, and 3 for a low quality (e.g., trees with thick branches). The value.levels refer to the applied assortment tables of Offer and Staupendahl (2018).

logging.method

Logging method, with "manually" for motor-manual logging using a chain saw, "harvester" for logging with highly mechanized forest harvesters, or "combined" for a combination of the previous methods dependent on the mean diameter.

species.code.type

Type of code in which species is given. "en" for English species names or "nds" for numeric species codes used in Lower Saxony, Germany. For a list with the available species and codes call get_species_codes.

method

argument that is currently not used, but offers the possibility to implement alternative parameters and functions in the future.

References

Fuchs, Jasper M.; Husmann, Kai; v. Bodelschwingh, Hilmar; Koster, Roman; Staupendahl, Kai; Offer, Armin; Moehring, Bernhard, Paul, Carola (2023): woodValuationDE: A consistent framework for calculating stumpage values in Germany (technical note). Allgemeine Forst- und Jagdzeitung 193 (1/2), p. 16-29. doi: 10.23765/afjz0002090

Offer, Armin; Staupendahl, Kai (2018): Holzwerbungskosten- und Bestandessortentafeln (Wood Harvest Cost and Assortment Tables). Kassel: HessenForst (publisher).

Examples

vol_skidded(40,
            "beech")

# species codes Lower Saxony (Germany)
vol_skidded(40,
            211,
            species.code.type = "nds")

# vector input
vol_skidded(seq(20, 50, 5),
            "spruce")

vol_skidded(rep(seq(20, 50, 10),
                2),
            rep(c("beech", "spruce"),
                each = 4))

vol_skidded(rep(seq(20, 50, 10),
                2),
            rep(c("beech", "spruce"),
                each = 4),
            logging.method = rep(c("manually", "harvester"),
                               each = 4))