This layer contains the relative forest growth stage classes.  The classification is based on Eucalypt growth stages identified by Max Jacobs (Growth habits of the eucalypts, 1955) and described in terms of the relative contribution of irregular to regular to regrowth forms to the total crown cover.  The data has been collected to SFRI standards for the old growth forest mapping program.

This layer contains the relative forest growth stage classes.  The classification is based on Eucalypt growth stages identified by Max Jacobs (Growth habits of the eucalypts, 1955) and described in terms of the relative contribution of irregular to regular to regrowth forms to the total crown cover.  The data has been collected to SFRI standards for the old growth forest mapping program.

This layer delineates one of the core forest resource attributes at 1:100,000 required for the delineation of old-growth forest.  The layer is vital to the old-growth forest analysis process that draws on forest resource and disturbance themes to stratify the forest in a repeatable and quantifiable way to determine areas of forest that meet the current definition of old-growth forest.  The layer should be used in conjunction with the EVC100 layer to take into account those EVCs that exhibit non - Jacobsian growth habits. That is, some EVCs will never exhibit late mature or senescing growth stages and the mature stage will be the oldest form.

Precision: 	10m to 100m
Determination:	Forest growth stages are registered to 1:25,000 and 1:100,000 base maps from aerial photography ranging in contact scales from 1:20,000 to 1:40,000. Positional accuracy is based on drafting pen thickness, base map accuracy and the nature of the boundaries mapped. Map errors of 0.5 to 3mm are reasonable (ie 12.5m to 300m).

No attribute accuracy assessment has been undertaken, however based on attribute checking procedures:
1.  Polygons GT 1ha: an error of 1 in 50 (approximately 98% accuracy)
2.  Polygons LT 1ha: an error of 1 in 20 (approximately 95% accuracy)

The growthstage code is made up of three components, a senescent growth form, a mature growth form and a regrowth form. The growthstage code is determined by an estimate of the relative contribution made to the crown cover by these three growth forms.

Each growth form is given a relative dominance value from the following table:

	d 	Crowns occupy greater than or equal to 50% of the total eucalypt crown cover.
	g	Crowns occupy between 30% - 49% of the total eucalypt crown cover.
	p 	Crowns occupy between 10% - 29% of the total eucalypt crown cover.
	t 	Crowns occupy between 1% - 9% of the total eucalypt crown cover.
	n 	Crowns occupy less than 1% of the total eucalypt crown cover.

This approach provides a very large number of possible combinations of which only a subset are logically consistent. These have all been verified. For a complete description of growth stage and maplabels refer to Stand Class Definitions and Polygon Labelling Guidelines for the State Forest Resource Inventory, Peter Elliot Department of Conservation and Natural Resources 1996.

Dataset Source: State Forest Resource Inventory (SFRI) project (North East), Gippsland, Midlands-Otways, Portland Wimmera - 1:20,000 photography.
  Bendigo Forest Mapping project (Goldfields) - 1:25,000 and 1:20,000 photography.
  Central Highlands Old Growth Forest Study - 1:25,000 and 1:40,000 photography.
  East Gippsland Old Growth Forest Study - 1:40,000 photography.


Dataset Originality: Primary

                            
                              Relationship to other Datasets: For selected areas, including the North-East, Gippsland, Midlands-Otways & Portland-Wimmera GSTAGE100 continues information derived from the 1:25,000 forest stand class dataset developed under the SFRI.  The GSTAGE100 layer must be used in conjunction with EVC100 due to limitations with forest growth staging for some EVCs.

Current Design Issues: This layer is designed principally to store the forest growth stage data interpreted from the API components of the Gippsland, Midlands-Otways, Portland Wimmera, Goldfields, North East, Central Highlands and East Gippsland Old-Growth Forest projects.  The layer  design accommodates both individual forest growth stage values and the amalgamated values required to delineate forest growth stage classes.

Future Design Issues: The forest growth stage layer will need to be updated with annual harvesting information to ensure currency.  The coding system used in the Gippsland, Midlands-Otways, Portland Wimmera, Goldfields and North East studies reflects the technique developed by the State Forest Resource Inventory, a different API technique to that used in East Gippsland and Central Highlands.

Related Documents: None

"A study of the Old-Growth Forests of East Gippsland",  Woodgate et.al. 1994
"Study of Old Growth Forest in Victorias Central Highlands", Forests Service Technical Report 96-3.
"Stand Class Definitions and Polygon Labelling Guidelines for the State Forest Resource Inventory". Peter Elliot, Department of Conservation and Natural Resources 1996
"Study of Old-growth Forest in Victoria's North-East", forest Service technical report 98-1.
"Old-growth Forest study of Gippsland Victora - Modelling of Old-growth Forrest Status". Study Report. Stephen Farrel & Milos Pelikan (Unpublished Report), 1999.
"Old-growth Forrest Study of South - Western Victoria: Portland Wimmera and Otways- Midlands - Modelling of Old-growth Forest status", Study Report. Stephen Farrell and Milos Pelikan (Unpublished Report), 1999.