THE EFFECT OF SAMPLE DRYING ON TREE RING ANALYSIS.

THE STATISTICAL EVALUATION OF DENDROCHRONOLOGICAL

ANALYSIS SAMPLES OF NORWAY SPRUCE ON THE ANTHROPOGENIC SOILS

Ing. Lukáš DragounUCOLIS 2012

Kostelec nad Černými lesy

This contribution presents the statistical characteristics of dendrochronological analysis samples (of increment borers). The aim of this study is to clarify the changes of single spruce rings size caused by samples drying and to determine the accuracy of the used method using Image analysis in WinDENDRO program. The data from 92 spruce samples on anthropogenic soils in the Sokolov region were obtained and will be further specified. Because the data evaluation is rather time-consuming, the presentation contains partial results only but they will be processed and published later. The study was financed by the IGA fund Faculty of Forestry and Wood Science, project – Dendrochonological analysis on anthropogenic soils in the Sokolov region, no. 20124351 (43140/1312/3116).

Abstrakt

Basic questions:Does sample drying affect the size of samples

and individual tree rings?

Does the drying differ with varying position of tree rings in the sample?

Does the change in portion of early and late width affect drying of individual tree rings?

The goals

Sampling98 samples were taken51 samples were measured in dried condition

Tree ring analysisOf damp samplesOf dried samples

Statistical data analysisSample dampness

Weight method

Methods

Accuracy of tree ring analysisSample 73 72 A 72 B

73 EARLY-WIDTH

72 EARLY-WIDTH

Average ring size 2,28 2,15 2,12 1,33 1,68

Standard deviation of tree ring 0,01 0,04 0,03 0,04 0,1

Number of tree rings 34 33 30 34 33

Average sample size 75,3 71,1 63,5 45,3 55,5

Standard deviation of sample 0,06 0,22 0,17 0,25 0,58

Accuracy of tree ring analysis – extreme rings

Average dampness of the samplesWhen taken away 45 %Damp samples 38 %Dried samples 8 %

There was a significant difference between damp and dried samples (T-test for Dependent Samples) and between individual tree rings (Wilcoxon Matched Pairs Test)Paired T-test: t=27,61, df=50; p < 0,01Wilcoxon test: t=20366,5, p < 0,01

Damp and dried samples comparison

Difference between damp and dried samples and individual tree rings

Change of sample size

Tree rings are aligned to the

core of sample

For 10 cm of sampleMean 3.24

Mean error 0.09Median 3.19

Standard deviation 0.67Variance 0.45Minimum 2.07Maximum 5.01

Change of sample size

Tree rings are aligned to the

edge of sample

Linear regression confirmed strong relationship between tree ring position in sample and drying out intensity.

Model explains only low amount of variability.p < 0,01R-squared = 0,013It is evident, that big amount of remaining

variation can be explained by other variables.

Effect of tree ring position on drying

Effect of tree ring position on drying

There was a significant difference between damp and dried samples.paired T-test; t=27,61; df=50; p < 0,01 Wilcoxon test; t=20366,5; p < 0,01Average tree ring size difference was 3 %.

The position of tree ring in sample affect its drying out.Linear regressiondrying out % (y) = 3,9119 – 0,0346 * year (x)Tree rings remote 30 years between each other differ in

drying out for 1 %. The relationship between drying out and early/late

width were not tested due to high measurement error. This is an objective for subsequent research.

Summary

Questions?...

ReferencesStatistical analyses were carried out in Statistica

software.Thanks for help with statistical analyses to Ing.

Daniel Zahradník, Ph.D.The study was financed by the IGA fund of

Faculty of Forestry and Wood Sciences, project – Dendrochronological analysis on anthropogenic soils in the Sokolov region, no. 20124351

Thanks for your attention