AAIR Project: Sub Task 5.2 Construction of the geographical database

Participant : The Forestry Authority,

Northern Research Station,

Roslin, Midlothian,

Scotland, EH25 9SY

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

Description:

The compilation of a geographic database for windthrow monitoring areas in Britain to be subsequently used in other tasks within this project for model derivation and validation.

Inputs:

Data layers representing site characterisitics (Digital terrain model and derived topographic variables, soil maps); forest characteristics (compartment map and associated aspatial database of stand features, surveyed heights at known locations); actual windthrow maps derived from aerial photographs; and windthrow predictions using algorithms of the windthrow hazard classification. Further data layers will be produced after progress in other tasks - Wind and snow climate predictions following derivation of best method in Task 5.1 by Forestry Authority, MLURI and Umea. Tree height maps from orthophotography in Task 4.2 by MLURI and Forestry Authority.

Outputs:

GIS data layers representing site, stand and windthrow. Digital terrain models to Task 5.1 for wind climate predictions by Forestry Authority. Aerial photographs to task 4.2 for orthophotography by MLURI.

Method:

Eight monitoring areas have been studied to date by the Forestry Authority. Of these 2 have been identified for task 5.1. 3 sites will be chosen from the remainder for further data collection and use in task 4.2 and 7.3. Data layers will be acquired and added to existing layers held in the IDRISI GIS system. The area of coverage will be extended from the detailed montitoring area to the wider forest district.

Uses:

The datasets will provide base information for a number of subtasks - in particular 4.2 (MLURI), 5.1 and 7.3 (Forestry Authority).

References:

Bell, P.D., Quine, C.P., and Wright, J.A. (in press) The use of digital terrain models to calculate revised windiness scores for the windthrow hazard classification. Submitted to Scottish Forestry.

Miller, K.F. 1985 Windthrow Hazard Classification. Forestry Commission Leaflet 85, HMSO, London.

Quine, C.P. and Bell,P.D. (in prep) Initial results from windthrow monitoring areas in upland Britain.

Quine, C.P. and Reynard, B.R. (1990) A new series of windthrow monitoring areas for upland Britain. Forestry Commission, Occasional Paper 25, Forestry Commission, Edinburgh.

Quine, C.P. and White, I.M.S 1993. Revised windiness scores for the windthrow hazard classification: the revised scoring method. Forestry Commission Research Information Note 230, Forestry Commission, Edinburgh.

Sub Task: 5.2

Participant: The Forestry Authority

MODELS USED FOR DATA ANALYSIS

I. Model Name:Windthrow hazard classification

II. Source of Model:NRS

III. Computer language:Turbo pascal

IV. Hardware needed:386 with maths coprocessor

V. Data Inputs needed:

• DTM

• Soil map

• Compartment map

• Sub-compartment database

• Wind zone (location)

• Age/Yield Class/Height relationships

• Thinning map

VI. Model Outputs

• A. Tables/Statistics

• % Damage by subcompartment

• Hazard Class area distribution
  
  

• B. Maps/GIS datalayers

• Topex sector and total

• Windiness score (as Miller 1985, or Quine and White 1993)

• Soil score map

• Hazard class map

• Top height map

• % Damage by subcompartment at specified year

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

• Poor accuracy

• Uncertainty due to

• DTM resolution (50m)

• Accuracy of yield class estimates

• Soil representation in map form

• Boundaries of subcompartments

• Model relationship of hazard class/top height/%damage

• Inter-annual climatic variability

VIII. Existing linkages between data and software:

• Oracle>Ascii>IDRISI

• IDRISI>Ascii>CSS Statistica

• NTF>Turnbull Jeffrey>IDRISI

• IDRISI>ERDAS

IX. GIS Software used:

• IDRISI

X. Modelling Software used:

• Turbo Pascal

XI. Database Software used:

• CSS Statistica (Stats package)

• Oracle

XII. Any other comments:

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

May 1995