lmfor (version 1.6)

BrkRes: Breaking resistance (=bending strength) of birch wood samples

Description

Measurements of the breaking resistance of wood samples from a total of 118 downy birch (Betula pubescens) trees.

Usage

data(BrkRes)

Format

A data frame with 274 observations on the following 7 variables.

Tree

Tree id (numeric)

Resistance

Breaking resistance, MPa

Density

Wood density (as air-dry in 12-15% moisture) , g/cm^3

FibreLength

Fibre length, mm

RingClass

Categorical with three levels indicating the position within the stem. 1=near the pitch (inside), 2=middle, 3=near the bark (outer).

SeedOrigin

Binary variable about the origin of the tree: 1=from seed, 0=sprouted.

Site

Categorical site class with four levels.

Details

A total of 1 - 4 wood samples per tree were collected. The samples were classified to three ring classes according to the distance of the sample from the pith. Each sample was measured destructively for breaking resistance in the laboratory. The measured variables also included wood density. The data has been collected by Hanna Joronen, Katri Luostarinen and Veikko Mottonen.

References

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

Joronen, H. 2020. Taivutusmurtolujuuteen ja kimmokertoimeen vaikuttavat tekijat hieskoivulla nuorpuussa ja aikuispuussa seka niiden mallintaminen lineaarisella sekamallilla. Master's thesis, University of Eastern Finland.

Examples

# NOT RUN {
data(BrkRes)

brmod1 <- lme(Resistance~RingClass+Density, 
          random=~RingClass-1|Tree, 
          data=BrkRes)
# }