AAIR Project: Sub Task 2.3 Preparation of a tree-pulling database

Participant : The Forestry Authority,

Northern Research Station,

Roslin, Midlothian,

Scotland, EH25 9SY

Contact: C P Quine, B A Gardiner, P D Bell.

Description:

Preparation of a tree-pulling database (divided into static and dynamic pulling).

Inputs:

a. Static Tests

Compulsory fields - species, tree height, diameter at breast height (1.3 m), overturning moment, location (latitude and longitude), site preparation and soil type, originator of data.

Optional fields - Spacing, root plate width and depth and weight, angle of stem at maximum applied moment, stem weight, crown depth and width, diameters of stem at various heights, elevation of site, soil wetness at time of pulling.

b. Dynamic tests

Compulsory fields - species, tree height, diameter at breast height (1.3 m), frequency of sway with crown, location (latitude and longitude), site preparation and soil type, originator of data.

Optional fields - same optional fields for static tests plus damping in contact with neighbours, damping without contact, damping without crown, frequency without crown, Youngs modulus.

Outputs:

Input data to an agreed format, with rules governing usage, updating and copying. Data will be available to all participants as Excel 5.0 spreadsheet.

Method:

Existing Forestry Authority database will be supplemented by data from literature, from Joensuu and Galway participants, and from personal contacts who have carried out relevant work.

Uses:

The database will be used by the Forestry Authority in Task 3.1 to develop empirical models of stem breakage and overturning, and by Joensuu to calibrate the mechanistic model in T 3.3.

References:

Fraser, A. I. and Gardiner, J. B. H. 1967. Rooting and stability in Sitka spruce. For. Comm. Bull., 40, 1-28.

Sub Task: 2.3

Participant: The Forestry Authority

MODELS USED FOR DATA ANALYSIS

I. Model Name: Puldbase.xls, Sway.xls

II. Source of Model: Forestry Commission

III. Computer language: Excel 5.0 for Windows

IV. Hardware needed: 386/486/586 PC

V. Data Inputs needed: Measurements on trees pulled over, measurements on trees either swayed artificially or by the wind.

VI. Model Outputs

• A. Tables/Statistics

• Puldbase.xls - Empirical mathematical relationships relating the overturning moment (N m) required to overturn trees and the tree and site characteristics (tree species, height, diameter, stem weight, root weight, root depth, soil type etc.).

• Sway.xls - Empirical mathematical relationships relating tree natural frequency and damping to tree characteristics (tree species, height, diameter, crown weight etc.)

• B. Maps/GIS datalayers

VII. Accuracy/Sources of Uncertainty/Method of Handling:

The main source of inaccuracy is likely to be in interpretation of some of the historical data. Full details of all the Forestry Authority tree-pulling experiments still exist on paper and selected cases will be checked against the entries on computer to ensure that there has been correct interpretation and loading. Other variability will result from the natural variability in trees, differences in identification of soils and inaccuracy in the measuring equipment. However, the biological variability will dominate other sources of inaccuracy. Sorting the data by species and soil has given regressions with r2>0.6 for overturning moment against stem weight.

Regressions will also be checked where possible against independent data from other pulling experiments with the same species on the same soils - for example past work by Galway and planned work by Joensuu.

VIII. Existing linkages between data and software:

Regressions have been completed for Sitka spruce, Norway spruce, Douglas fir, Scots pine, Corsican pine, Lodgepole pine, Grand fir, Noble fir and Japanese larch on Brown earth, podzol, gley, deep peat, Ironpan, and calcareous soils.

IX. GIS Software used:

N/A

X. Modelling Software used:

Microsoft Excel 5.0

XI. Database Software used:

Microsoft Excel 5.0

XII. Any other comments:

Prepared by C P Quine/B A Gardiner/ P D Bell

May 1995