1. Inventories 1.1
Forest Inventory programs have been conducted by the Department of Natural Resources since 1953. Since then, the methodology of inventory collection has changed several times. Initially, field strip cruises were the preferred method which has now progressed to a combination of field sampling and photo interpretation. Inventories carried out by Titus Smith 1801-1802, and later Fernow, 1912, were comprised of walking tours whereby the evaluators talked to the local forest owners and operators as well as residents. No extensive or systematic field sampling took place until after 1950.

1.2 The inventory information included in this discussion is derived from aerial photography, acquired between 1985 and 1993, and photo interpretation, which is verified by field sampling.

2.0 Why Do We Need Forest Resources Inventories

2.1 The Provinces' forest resources, while contributing to our economy, health and well being, are experiencing increased competition for their use. Crown land, for example, is used not only for wood production, but also for hiking, hunting, fishing, camping, wildlife habitat protection, biodiversity protection, and research. Nova Scotians want to insure that future generations have access to and continue to benefit from forest resources, through sustainable development and management.

2.2 In order to develop and manage forest resources on a sustainable basis their current status and health need to be determined. This is accomplished in part through forest inventories which are designed to monitor changes to resources. Sustainable development depends on knowing what resources exist, the health and condition of those resources and how the resources are used.

2.3 Nova Scotian's want to use their resources in a sustainable manner. In order to do so we need to be able to provide inventories of existing resources and have in place programs which will monitor changes to our resources. Sustainable development depends on knowing what we have and how we are using what we have.

3.0 Inventory Background:

3.1 Previous inventories include Titus Smith's walking survey of 1801-02 which was sponsored by Lieutanant-Governor Wentorth, and Fernow's 1912 inventory which was reported in the document entitled "The Forest Conditions Of Nova Scotia" ( Fernow; Dr. B.E. 1912). The Fernow survey was sponsored by the Province and the report published by the Canada Commission of Conservation. With the passing of the Canada Forestry Act in 1952 the Province and the Federal government cost shared a forest inventory program which was completed in 1957. The results were reported in the document "The Forest Resources of Nova Scotia" (Bulmer, R.M. and L.S. Hawbolt 1958). This report provided the first complete set of large-scale photographs and forest type maps which showed the most comprehensive information on species, volumes and acreages for the Province.

3.2 Between 1965 and 1971 the Department of Lands and Forests implemented what was designed as the first continuous forest inventory program for the Province, using a series of temporary sample plots. The program was the first of its kind to be carried out by Department staff and had a planned 7 year cycle. Reports and compilations were published from 1968 to 1973.

3.3 Methodologies changed in 1980 with the introduction of sampling with varying probabilities (3P). A multi stage process was used to select and sample stands. Point sampling, which gives a variable plot size dependant on tree size was used in place of the strip cruise method used by previous inventories. The 3P program used metric units, and a tiered system for the selection of field sampling units. The trees in selected plots were measured using a dendrometer to determine product and form . This program ran for 10 years and was completed in 1990. Details of this inventory process can be found in the document "Multistage Integrated Forest Field Specifications" ,1988, published by the Department of Lands and Forests.

3.4 The current system using photo interpretation for determining variables for every forest stand in the Province began in 1987. The resultant data base, completed in 1996, and refered to as the 1995 inventory, is the most recent roll up of a Provincial inventory and is described in detail below.

3.5 In addition to the above the Department maintains a continuous forest inventory system based on approximately 1965 permanent field sample plots located across the Province. This system began in 1965 and plots are re-measured every five years. The permanent sample plot (PSP) program was designed to track volume growth and mortality of the natural forest. This program is continuing today in an expanded and revised format. It is planned to measure approximately 3500 PSP's every five years, for a variety of values including a broader assessment of vegetation, wildlife habitat and elements of biodiversity.

3.6 Details of previous inventories can be obtained from either the Department Library in Founder's Square in Halifax or from the Inventory Section in Truro.

3.7 Tables 1 through 40 found at this web site report forest inventory information derived from the 1995 inventory. NOTE: Recent field inventories suggest that the older age classes occupy more area than shown in some of the tables (for example, A3).

3.8 Information reported here are derived from aerial photography, with field sampling verification, and are thus intended to be used for strategic analysis and assessment on a general basis. If the reader is planning to use the data in an operational mode, then further field verification should be carried out.

3.9 In the tables the following ownership definitions apply.

Crown land Freehold Land owned by the Province and administered by the Department of Natural Resources.

Crown leased Land owned by the province but leased out for management purposes through legislation or cabinet decree.

Federal land Land administered by the Federal government

Large private Land held by one or more owner or groups in parcels totalling more than 400 hectares.

Large industrial Land held in parcels totalling more than 400 hectares by corporations or individuals for which a management plan has been prepared through Federal/Provincial Forestry agreements.

Small private managed Land held by individual owners holding less than 400 hectares and having a registered management plan prepared under Federal Provincial Forestry agreements

Small private Other Land held in parcels not covered by the above definitions

4.0 The Spatially Related Forest Resources (1995) Inventory

4..1.1 The 1995 inventory is derived, in part from air photo interpretation. True colour air photography at the scale of 1:10 000 is interpreted for 4 variables, in accordance with specifications designed by the inventory section. Forest stands one hectare in size or greater were delineated. Stands split by urban property, other ownership boundaries and forest management treatments may be smaller in size.

4.1.2 Variables assessed include species in 10% classes, crown closure in percent (no classes), average stand height (height of average co-dominant trees) to the nearest metre and land capability (originally in 7 imperial classes and later changed to 13 metric classes). If a second story for the stand was detected, a forest type , average height and crown closure were also estimated for that story.

4.1.3 Any particular stand could also be labelled as being an all height stand which are stands comprised of at least 3 tree layers or more. These stands are thought to be uneven age stands. Species, average height, crown closure and land capability however, were also provided for the all height stands.

4.1.4 Non forest stands were also delineated. A list of categories for non forest stands are provided below. Further detail can be found in the Forestry Division internal publication entitled "Photo Interpretation Specifications" available under separate cover. Every hectare in the Province was interpreted and classified.

Forested/Non Forested classifications Every hectare of land is classified as either forested or non-forested using the following categories.

Forested

• Natural stand
• Treated stand- treatment not classified
• Christmas Tree Stand
• Sugar Bush
• Old field returning to forest
• Wind throw
• Dead stand < 25% crown closure of live residual material
• Dead stand 1 26-50% crown closure of live residual material
• Dead stand 2 51-74% crown closure of live residual material
• Dead stand 3 same as Dead 1 but with regeneration
• Dead stand 4 same as Dead 2 but with regeneration
• Dead stand 5 same as Dead 3 but with regeneration
• Research stand
• Seed Orchard and Seed production area
• Treated stand with Treatment classified
• Plantation
• Clear cut

• Wetlands general
• Beaver flowage
• Open Bogs
• Treed Bogs
• Brush
• Rock Barren
• Barren
• Agriculture
• Urban
• Alders <75% cover- dry land ( now Classed as forested)
• Alders 75% or greater- dry land
• Blue Berries
• Sanitary land fill
• Beach
• Gravel Pit
• Miscellaneous

4.2 Data base creation

4.2.1 Individual stands were digitized from photographs, using linear stretch adjustment, and attributes were placed into the data base tables of the Arc/Info GIS. Stands were individually numbered within map sheets, and thus each forest stand in the province is uniquely identified and spatially located. The Department of Municipal Affairs' topographic series base maps were used as tiles (or building blocks within the GIS). Mapsheets were grouped by county and a computer library created for each county.

4.2.2 The map projection used was the Modified Transfer Mercator (MTM) and the datum was the Average Terrestrial System (ATS 77) created by the Nova Scotia Geomatics Centre. The ATS 77 is the provincial standard for the topographic base mapping.

4.2.3 The entire Province was completed (entered) by 1996, ten years after the process began.

4.3 Calculated Forest Attributes.

4.3.1 Using the interpreted variables and algorithms developed by the Division, the following additional stand attributes were calculated.

4.3.1.1 Age

Land capability and height were used to determine stand age. The stump age algorithm was derived from the Revised Normal Yield Tables (RNYT) for Nova Scotia Softwoods (DNR Research Report no. 22,1990). Hardwood algorithms were derived from applying a standard adjustment to the softwood algorithms. The maximum age of any stand calculated by the algorithm is 110 years.

4.3.1.2 Total Basal Area

Algorithms, based on the Nova Scotia RNYT were used to calculate maximum total basal area for every stand with a height of 16 feet (5 metres) or more. Please note the algorithms calculate TOTAL and not MERCHANTABLE basal area. Separate algorithms for softwood and hardwood were used with the exception that the softwood algorithm was applied to Aspen (Populus Tremuloides Michx. ) stands because it was determined that Aspen stands grow more like softwood stands, than other hardwood stands.

Stand basal area values were reduced by the percent crown closure and by the species portion (percent ) for each stand. The algorithms are listed below.

Softwood maximum BA= 148.418+2.58554(Ht)-.033254(Ht2)+.000296( Ht3) -.000001256(Ht4)

Hardwood maximum BA= 8.35106+2.77608(Ht) - .000066369(Ht3)

Actual Softwood BA= (Softwood Maximum BA)(Percent Crown Closure) (Softwood Species Percent)

Where: Ht = The interpreted stand height (which is an estimate of Lorey's Height) in feet

BA = Total Basal Area per acre

4.3.1.3 Merchantable Volume

An algorithm was developed and used for converting total basal area to merchantable volume. The same algorithm was applied to hardwood and softwood portions of stands. The Total Basal Area for softwood and hardwood, calculated above, were multiplied by the merchantable volume conversion factor listed below.

The volume and basal area calculations were carried out for both stories of each stand.

Mrvol= -14.1774+.77012(Ht) - .0007559(Ht2) -.000026698(Ht3) + .00000000125277(Ht5)

Where: Mrvol = Merchantable Volume Conversion Factor Ht = The interpreted stand height in feet

4.3.1.4 Average Diameter

Algorithms derived from the RNYT were used to calculate average diameter values for the softwood and hardwood portions of each stand.

• AVDI.SW= 1.9561+.1138(Ht)-.00163(Ht2) + .00002701(Ht3) - .0000000008733(Ht4)
• AVDI.HW= 2.30797+.01309(Ht) + .0031781(Ht2) - .00007473(Ht3) + .0000007688(Ht4)
  Where: AVDI = Average Diameter in cms.

The Stand Average Diameter is calculated by summing the proportions of the individual diameters for hardwood and softwood in that stand.

Comments may be sent to the attention of:
Manager, Forest Inventory by mail at:

NS Department of Natural Resources,
PO Box 68, Truro, NS, B2N 5B8

by fax at (902) 893-6102, or E-mail mailto:pgtownse@gov.ns.ca)