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1958 forest outline shown with the 2000 orthophotos. Brookvale, PEI.

SHARON M. MCDONALD &

WILLIAM M. GLEN

DEPARTMENT OF ENVIRONMENT, ENERGY & FORESTRY

FORESTS, FISH & WILDLIFE DIVISION RESOURCE INVENTORY & MODELING SECTION

APRIL 2006

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Introduction Under the carbon account process of the Kyoto protocol reforestation and afforestation are treated differently. Afforestation is defined as the establishment of tree cover on land that has not been in forest for the previous fifty years. The best source of information on whether or not an area was forested fifty years ago is the aerial photography taken during the summer of 1958. The need for this information provided the incentive for this mapping project. While it would have been desirable to classify the forest as to species, heights, etc. as in a traditional inventory, unfortunately the available resources did not allow this. However the project was able to obtain the required land use information of forest verses non-forest with some breakdown of both categories. Aerial Photography Acquisition During the spring of 1958, the Royal Canadian Air Force contracted Kenting Aviation Ltd. of Charlottetown, P.E.I. to conduct an aerial photographic survey of Prince Edward Island. The photography was acquired during the period June to August. Unlike the twin-engine aircraft used today, this aerial survey used a single engine 1956 Cessna 180, aircraft registration number CF-HLS. Figure I shows a 1954 Cessna 180 similar to the aircraft used in this project. The aircraft was described as follows, “The Cessna 180 is a general aviation light aircraft produced by the Cessna Aircraft Company of Wichita, Kansas. This aircraft was in production from 1952 through 1986, and was designed to be a heavier, more powerful aircraft than the Cessna 170. Like the 170 model, the 180 were equipped with conventional tail wheel landing gear.”

Figure I: 1954 Cessna 180

The aircraft’s specified true altitude was recorded as 8200 feet, producing a scale of

approximately 1:15,840 (4 inches to the mile). The camera type was listed as ‘RC5A 225', using a Pan2X filter with Super XX film. L. Terry piloted the Cessna and G. George operated the camera. Overall, the quality of the aerial photographs was quite satisfactory. Heavy cloud cover was a problem in only a few photographs. Generally, the weather was reported as bright with light haze.

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The film negatives for this photography are held at the National Air Photo Library in Ottawa and copies and enlargements can be purchased from them. Their website is http://airphotos.nrcan.gc.ca/

The set of photography used in this project is held at the J. Frank Gaudet Tree Nursery, Department of Environment, Energy and Forestry on the Upton Road, Charlottetown. The Project

Interpretation of the 1958 photographs began in April 1994 and continued as time and resources permitted until it was completed late January 2006. A list of the staff involved in the project is located at the end of this report. The information assembled by this project has been analyzed to look at the Island’s forest cover and, by comparison with other inventory projects, to help to fill in the story of forest area change during the 20th Century. The findings of this study and other inventories were also used to determine the forest types that have regenerated on areas identified as harvested in 1958. Methodology

From 1994 to 2004 Forestry staff completed interpretation of the 1958 photography. The Island’s landcover was determined using the classification shown in Table I. The forested areas were not classified to forest type or tree species due to limited resources.

Table I: 1958 Forest Inventory land use codes

Non Forest Types Forest TypesCL cleared land CC clearcutEP excavation pit FC forest coverOR orchard PC partial cut standRD road PN plantationRR railway right of way RV reverting (cleared land reverting to forest)SD sand dune WW open water WL wetland

Clear Mylar hardcopy base maps were created for each of the 212 mapsheets that cover

the Province. These maps included the coastline, roads, railway, rivers and the 1990 forest outline and were plotted at the same scale as the photography (1:15,840). The aerial photography was examined using stereoscopes and the forest features were outlined on the photos. The information was then transferred to the Mylar base maps using a light table. Areas of new forest and harvested areas were also identified. All polygons on the manuscript maps were labelled with the appropriate landcover codes. The manuscript maps were then scanned, georeferenced and the new line work was created in ArcGIS using the ‘heads-up’ digitizing method. The final digital map is available in ArcGIS SHP and MapInfo TAB formats. (Note no corrections were made for any changes to the road or railroad features between 1958 and 1990).

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Findings Table II shows the results of the photo interpretation and digitizing.

Table II: Land cover of Prince Edward Island 1958

Area Non Forest Types (hectares) Area Forest Types (hectares)Cleared land** 290,933 Clear cuts 11,003 Excavation pits 8 Forest cover 205,327 Orchards 27 Partial cut 18,404 Roads* 10,419 Plantation 27 Railway* 1,423 Reverting land 8,726 Sand dunes** 464 Total Non Forest Area 340,607 Open Water** 10,042 Total Forest Area 234,761 Wetlands** 18,565 Total Area 575,368

* 1985/88 base map data ** Not mapped to 2000 resource inventory specifications, cleared land included all non forest land not classified in Table II

A comparison between the forested areas of 1958 and the forested areas, interpreted from the 1935/36, 1980, 1990 and 2000 aerial photography is shown in Table III. The table also provides the Canadian Forest Service’s estimate of the Island’s forest area in 1961. Study results from this project suggest that the 1961 number was under estimated by about 10%. Figures II and III provide an overview of the forest area change during the 20th century.

Table III: Forest Area of Prince Edward Island 1900-2000

Year Area (hectares) SourceCirca 1900 177,900 1935/36 Forest Cover type mapping project 1935/36 186,283 1935/36 Forest Cover type mapping project 1958 234,762 1958 Forest Inventory1961 210,400 Canadian Forestry Statistics 1961, report 25-202, page 5 1974 256,000 Maritime Resource Management Services 1980 273,593 1980/82 Forest Biomass Inventory1990 279,193 1990/92 Forest Biomass Inventory2000 263,207 2000/02 Corporate Land Use inventory

Notes: 1: The 1900 and 1935/36 numbers were published in Prince Edward Island 1935/36 Forest Cover Type Mapping, dated May 1997 by W. M. Glen, Department of Agriculture and Forestry. The area in circa 1900 was determined from the origin of stands as shown by the 1935-1936 aerial photography 2: There is no forest area figure for 1967 even though there was an inventory. The 1967 Acres Inventory did not report total forest area only merchantable forest area. 3: Maritime Resource Management Services (M.R.M.S.) in Amherst, Nova Scotia generated the 1974 area numbers from the 1974 aerial photography. 4: The 1980 and 1990 areas has been recalculated after the digitization of those inventories and the numbers vary slightly from those previously published. 5: Forest area includes; high forest, plantations, alders, clearcut, forested wetlands.

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Figure II: Forest area 1900 – 2000

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Figure III: Percentage of forest cover of the Province 1900 – 2000

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The completion of this project provides an opportunity to analyze a number of changes that have occurred in the Island’s forests over the past century. For instance, the analysis of regeneration on the 1958 harvested areas was done to illustrate the types of information that may be derived.

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The regeneration of harvested areas identified in 1958 Clearcuts The completion of this project allowed researchers to derived more information from the earlier 1935-1936 mapping and the 1980, 1990 and 2000 forest inventories. The first step in this analysis was to identify the forest types for areas that were identified as clearcuts in 1958. As shown in Table II, 11,003 hectares were recorded as clearcuts. These clearcut areas were compared to the 1935/36 mapping and the forest types were determined as shown in Table IV.

Table IV: 1935 description of 1958 clearcuts

1935 Description Hectares Comments SS >74% softwood 4,230 SH >50% softwood and <75% softwood 1,600 HS >50% hardwood and <75% hardwood 828 HH >75% hardwood 288 Clearcut 1,475 RV Reverting land 488 Old fields regenerating Cleared land 1,750 Land that probably regenerated between

1935 & 1958 Wetlands and alders 248 Other forest land (unclassified) 96 The major 1935 forest types of Softwood (SS), softwood-hardwood (SH), hardwood-softwood (HS) and hardwood (HH) were used in the analysis of the regeneration of the 1958 clearcuts (see Table IV for the definitions of this categories). During the analysis, it became evident that two general site types were involved; the lowland or moist sites and the upland or drier sites. The P.E.I. agriculture soils were used to classify the 1958 harvest areas into these two categories. Soils classified as organic, poor or imperfectly drained were included in the lowland category. The well drained or rapidly drained soils were classified as upland. Areas identified in 1935 as SS on poorly drained sites were followed from 1980 to 2000. Note that areas that did not remain in forest cover were excluded from the analysis. Figure IV shows the forest classification of these sites based on three Forest Inventories (1980, 1990 and 2000).

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Figure IV: Percentage of 1958 clearcuts on lowland sites identified in 1935 as SS

Poorly Drained Areas - 1935 Softwood

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The trend overtime has been an increase of the percentage of softwood (SS) within the harvested areas. In 1935, these sites were predominately Black Spruce and remained so through to the 2000 Forestry Inventory. The amount of hardwood (HH) has decreased in these areas over time but, as shown in Figure IV, HH was never a high percentage on these sites. Figure V shows the regeneration of the 1935 softwood (SS) forest on upland sites that were identified as cut in 1958. The results provide a less clear picture but the percentage of hardwood (HH) on these sites is approximately double that of the lowland sites.

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Figure V: Percentage of 1958 clearcuts on upland sites identified in 1935 as SS

Well Drained Areas - 1935 Softwood

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There were only 288 ha of hardwood (HH) forest identified as cut in 1958. This was primarily due to the lack of HH in 1935. The forest had been under continued heavy pressure for fuel wood and as a result, the area of hardwood was only 6.5 % of the forest in 1935 (Glen, 1997). Analysis showed that there was no HH cuts on the lowland or poorly drained sites. Figure VI shows the regeneration of the HH forest on the upland site type.

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Figure VI: Percentage of 1958 clearcuts on upland sites identified in 1935 as HH

Well Drained Areas - 1935 Hardwood

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The regeneration of these harvested areas shows a continuous increase in the percentage of HH from 1980 to 2000. By 2000, the areas are 90%+ back to their 1935 classification, strongly suggesting that harvested upland hardwood sites will return to hardwood given sufficient time. However, this does not mean that the same hardwood species are present in 2000 as in 1935. Unfortunately the 1935 forest mapping did not have species information. The subsequent inventories 1980,1990 and 2000 do have this information and further analysis is possible.

The regeneration of mixed wood forest type of softwood-hardwood (SH) behaved like the softwood forest type on the lowland sites with increasing conifers over the study period. The HH and SH categories stayed relatively constant at approximately 20% while the HS category lost significant area between 1990-2000. Figures VII and VIII show the regeneration of the SH forest types

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Figure VII: Percentage of 1958 clearcuts on lowland sites identified in 1935 as SH

Poorly Drained Areas - 1935 Soft/Hardwood

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Upland sites of softwood-hardwood recorded as harvested in 1958 were similar to the HH type with increasing HH species during the period 1980 to 2000. Over the same period, the mixed wood and SS categories decreased.

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Figure VIII: Percentage of 1958 clearcuts on upland sites identified in 1935 as SH

Well Drained Areas - 1935 Soft/Hardwood

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The regeneration of the other mixed wood category of hardwood-softwood (HS) on the lowland sites showed a higher percentage of HH than did the SH type on the same site. On the upland sites, the regeneration of the HS type shows the same pattern as the HH type. Figures IX and X show the regeneration patterns of the HS type.

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Figure IIX: Percentage of 1958 clearcuts on lowland sites identified in 1935 as HS

Poorly Drained Areas - 1935 Hard/Softwood

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Figure X: Percentage of 1958 clearcuts on upland sites identified in 1935 as SH

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Partial Cuts The project also provided an opportunity to look at partial cuts – sites where 20%-50% of

the trees in the harvest area were not cut Table V provides a summary of the 1935 forest types which were classified as partial cut in 1958.

Table V: 1935 description of 1958 partial cuts

1935 Description Hectares Comments SS >74% softwood 1,108 SH >50% softwood and <75% softwood 588 HS >50% hardwood and <75% hardwood 179 HH >75% hardwood 241 Clearcut 325 RV Reverting land 25 Old fields regenerating Cleared land 349 Land that probably regenerated between

1935 & 1958 Wetlands and alders 47 Other forest land (unclassified) 1,999 The partial cuts were primarily restricted to the softwood, softwood-hardwood and hardwood-softwood forest types. There was insufficient area of the hardwood type to carry out an examination of the covertype response. As in the case of the clearcuts, the two site conditions of upland and lowland were separated and the results are reported where there was sufficient area. Partial cuts in the softwood forest types were separated in to the upland and lowland categories. The resulting forest cover in 1980-2000 is shown in Figures XI and XII. The response of the SS types to partial cutting was different when compared with the clearcut sites. The two site types behaved similarly with approximately 65% of the area resulting in SS or SH, and the remaining 35% resulting in HS and HH with a gradual increase in HH over the period 1980-2000. These finding suggests that the SS partial cuts may have been on slightly better (i.e. drier) sites than the clearcuts. The softwood/hardwood partial cuts show a similar pattern for both the upland and lowland sites (Figure XIII and XIV). These sites continue to provide a mixture of covertypes over the period with no apparent pattern.

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Figure XI: Percentage of 1958 partial cuts on lowland sites identified in 1935 as Softwood

Poorly Drained Areas - 1935 Softwood

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Figure XII: Percentage of 1958 partial cuts on upland sites identified in 1935 as Softwood

Well Drained Areas - 1935 Softwood

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Figure XIII: Percentage of 1958 partial cuts on lowland sites identified in 1935 as SH

Poorly Drained Areas - 1935 Soft/Hardwood

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Figure XIV Percentage of 1958 partial cuts on upland sites identified in 1935 as SH

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Figure XV: Percentage of 1958 partial cuts on upland sites identified in 1935 as HS

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There was only sufficient area to look at the partial cuts of HS stands on the upland sites. These sites have continued to be dominated by hardwood (HS and HH = 70%) over the period (Figure XV). Regeneration Summary The regeneration of forest types on areas identified by the 1958 mapping project show considerable variation. The correlation between regenerating forest and site types for the clearcuts was notable while the partial cuts do not provide as clear a picture. Summary This report provides an overview of the findings of this mapping project and also provides examples of how it may be used in conjunction with other information sources. It is hoped that the data will be used in new and other innovative ways.

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Staff involved in 1958 Forest Inventory: Photo Interpretation June 1994 Kris Ann Heaney April/ May 1997 Christoph Kreiger Spring 2004 Lori Rickard Spring 2004 Peter Sharkey Transfer June 1994 Kris Ann Heaney April/ May 1997 Christoph Kreiger November/Dec 2000 Ann Rattray Spring 2004 Lori Rickard Spring 2004 Peter Sharkey Digitizing June 1994 Kris Ann Heaney November/Dec 2000 Ann Rattray Spring 2004 Lori Rickard Spring 2004 Peter Sharkey Spring 2004 Sharon McDonald Spring 2004 Sandra Jamieson Summer 2004 Brandon Mol Data analysis Summer/winter 2005 Sharon McDonald Report preparation Fall 2005 /winter 2006 Sharon McDonald William (Bill) Glen Project management 1994-2006 William (Bill) Glen References Glen, William M., 1997; Prince Edward Island 1935/1936 Forest Cover Type Mapping,

Silviculture Development Section, Forestry Division, Prince Edward Island Department of Agriculture and Forestry, Charlottetown

Glen, W. M., 2003, 2000/02 Prince Edward Island Corporate Land Use Inventory Forest

Summary, Resource Inventory and Modeling Section, Prince Edward Island Department of Agriculture, Fisheries, Aquaculture and Forestry, Charlottetown.