dixon (version 0.0-9)

swamp: Tree Species in a Swamp Forest

Description

Locations and botanical classification of trees in a plot in the Savannah River. Locations are given in metres, rounded to the nearest 0.1 metre. The data come from a 1-ha (200 m x 50 m) plot in the Savannah River Site, South Carolina, USA. The 734 mapped stems included 156 Carolina ash (Fraxinus caroliniana), 215 Water tupelo (Nyssa aquatica), 205 Swamp tupelo (Nyssa sylvatica), 98 Bald cypress (Taxodium distichum) and 60 stems of 8 additional species. Although the plots were set up by Bill Good and their spatial patterns described in Good and Whipple(1982), the plots have been maintained and resampled by Rebecca Sharitz and her colleagues of the Savannah River Ecology Laboratory. There are slightly different versions of the Good plot data. Every time the plots are resampled, some errors are corrected. This is mostly a concern for the biologists. The different versions are very similar; they are all very good examples of a marked spatial point pattern.

Usage

data(swamp)

Format

A data frame with 734 observations on the following 3 variables.

x

Cartesian x-coordinate of tree

y

Cartesian y-coordinate of tree

sp

a factor with levels indicating the species of each tree:

ll FX Carolina ash (Fraxinus caroliniana)
NS Swamp tupelo (Nyssa sylvatica)
NX Water tupelo (Nyssa aquatica)
TD Bald cypress (Taxodium distichum)
OT Other species

References

Dixon, P.M. 2002. Nearest-neighbor contingency table analysis of spatial segregation for several species. Ecoscience, 9(2): 142-151.

Good, , B. J. & Whipple, S.A. 1982. Tree spatial patterns: South Carolina bottomland and swamp forest. Bulletin of the Torrey Botanical Club, 109: 529-536.

Jones et al. 1994. Tree population dynamics in seven South Carolina mixed-species forests. Bulletin of the Torrey Botanical Club, 121:360-368.

Examples

data(swamp)
plot(swamp$x,swamp$y, col=as.numeric(swamp$sp),pch=19,
		 xlab="",ylab="",main="Swamp forest")