crowdInd: Forest matrix crowding index - Seydack et al. 2011

In johngodlee/compInd: Forest tree-tree competition indices

Forest matrix crowding index - Seydack et al. 2011

Description

Forest matrix crowding index - Seydack et al. 2011

Usage

crowdInd(dbh, dbh_min = 10, dbh_max = 30)

Arguments

dbh	vector of DBH (diameter at breast height) measurements of competitor trees
dbh_min	minimum DBH threshold considered
dbh_max	maximum DBH threshold considered

Details

A simple competition index which returns the sum of DBH values of all competitor trees within user-defined DBH thresholds. Armin et al. (2011) use a minimum threshold of 10 cm DBH and a maximum threshold of 30 cm DBH.

Value

value of competition index for focal tree

References

Armin H.W. Seydack, Graham Durrheim, Josua H. Louw. Spatiotemporally interactive growth dynamics in selected South African forests: Edaphoclimatic environment, crowding and climate effects. Forest Ecology and Management. Volume 261. Issue 7. 2011. Pages 1152-1169.

Examples

data(bicuar)
nb <- nearNeighb(bicuar$x, bicuar$y, bicuar$stem_id, k = 4) 
lapply(nb, function(x) {
  nb <- merge(x, bicuar, by.x = "nb", by.y = "stem_id")
  crowdInd(nb$diam, dbh_min = 10, dbh_max = 30)
  })

johngodlee/compInd documentation built on Aug. 5, 2024, 8:44 a.m.