lmfor (version 1.7)

plants: Sapling counts from sample plots of sapling stands in Finland.

Description

Grouped Norway Spruce regeneration establishment data.

Usage

data(plants)

Format

A data frame with 1926 observations (fixed-area sample plots) from a total of 123 forest stands, with the following 8 variables.

spruces

The number of spruce saplings (both planted and natural)

stand

The stand id)

hdecid

The mean height of deciduous tree species

prepar

Site preparation method, categorical with 4 levels

stones

Binary indicator for stoniness

wet

Binary indicator for wetness

Details

The data are collected from 123 fixed-area sample plots with similar age of planted spruce saplings. The variables have been measured on fixed-area plots.

References

Miina, J. and Saksa, T. 2006. Predicting regeneration establishment in Norway spruce plantations using a multivariate multilevel model. New Forests 32: 265-283. tools:::Rd_expr_doi("10.1007/s11056-006-9002-y")

Mehtatalo, Lauri and Lappi, Juha 2020. Biometry for Forestry and Environmental Data: with examples in R. New York: Chapman and Hall/CRC. 426 p. tools:::Rd_expr_doi("10.1201/9780429173462")

Examples

data(plants)
library(lme4)
if (FALSE) {
glmm1<-glmer(spruces ~ (1|stand)+hdecid+as.factor(prepar)+as.factor(stones)+as.factor(wet), 
             family=poisson(), data=plants)
}