How aircraft assist fire fighting and map preparation in wooded regions of Canada
A VEDETTE FLYING BOAT with a survey camera mounted on the nose, where it is operated by a photographer in the cockpit in front of the pilot’s position. From a forestry point of view oblique photographs have proved of more value than the vertically taken photographs which are largely used in normal aerial survey. By viewing the photographs through a stereoscope and by noting the length of shadows cast by the sun, it is possible to assess the type and quality of a plantation.
THERE is a menace in the air. A heat haze broods over leagues of forest, flecked by the queer shapes of lakes where they reflect the brazen sky and veined with silver where broken water marks a drop in the level of a river.
The brooding silence is broken only by the drone of an aeroplane flying high above the trees. The atmosphere is hot and dry. When such conditions arise in the woods of Canada, there is danger of fire and an army of aviators is mobilized to combat an invader who knows no borders, no rules of war, no clemency.
Let us join in imagination the pilot of one of the patrolling seaplanes. His eyes range from the instruments before him to the leagues of forest and lake below him. The observer beside him ceaselessly scans the horizon. Now and then the observer talks into a microphone, sometimes to report the seaplane’s progress across the country, sometimes to talk to a friend at the base.
The pilot attracts the observer’s attention. A thin line of smoke rises above the tree-tops by a distant lake. The line of smoke has escaped the observer. A new note comes into the voice reporting over the radio The machine shifts off its course and heads across country to investigate.
The machine swoops down. The fliers see a camp fire and some men in red shirts beside it waving a greeting. These men may be one of the ground patrols cooking a meal, or they may be a party of surveyors. There is no danger there. The men know their business.
The pilot goes up again and back to his beat. A few minutes later another line of smoke is seen. It is bigger this time, and a warning goes out over the radio.
SEAPLANE OVER TYPICAL FOREST LAND of Canada in the neighbourhood of Blue Sea Lake, Quebec. The numerous lakes of Canada make ideal alighting places for fire-patrol aircraft, which use float undercarriages in the summer and skis in the winter. When a fire occurs, the best method ol fighting it can be quickly decided from an aeroplane. Aircraft are also able rapidly to transport the men and necessary equipment to the scene of the outbreak.
The woods are as dry as tinder. If a fire were now to take hold it might sweep unchecked for miles across the land. The machine swoops to investigate. The pilot has located a fire — the makings of a bad fire. A camp fire that campers thought was out has eaten through the subsoil and broken out hours after they have left. It has caught hold of the underbrush, and is eating into a grove of conifers. A radio warning is given and the men at the base camp are instantly alert. A big transport seaplane warms up at the dock. Another patrol aircraft is recalled and, with the pilot that gave warning, it flies to the base. Men, fire-fighting equipment and supplies are loaded into the bigger machine. The smaller aircraft must fetch more equipment and perhaps pick up the ground patrols and portable pumps stored permanently at some important outpost. The battle has begun.
The chief forester goes on board one of the smaller craft, and the party flies off. The fire is bigger now and, as the big transport seaplane alights on the nearest lake, the chief forester makes a hurried survey flight over the scene of action. He can see which way the wind is blowing, where the fire can be held in check, exactly where it can be attacked. His whole campaign can be determined at a glance from above. In the past, without the aid of aerial reconnaissance, fire fighters wasted hours, if not days, in travel by canoe towards the scene of the fire, and then they had to fight blindly and helplessly.
The men are landed. On stretchers and in packs, the tiny pumps, the hoses, the axes and the shovels are moved to the scene. In a few minutes streams of water are playing at the root of the
flames and trees are being felled. The roar of the flames is deadened by the hiss of steam. Sparks have carried the fire across the lake, but the outbreak is caught there in time, too. A gang is left to watch for further outbreaks, while the machines make a careful observation tour over the neighbourhood to make sure there is no more trouble. Then they head back towards their base. The skirmish is ended.
Thanks to the aeroplane in Canada the fight against forest fire can be kept at the skirmish stage. Quick action can prevent it from becoming a major engagement. Aerial fire patrol is expensive. It is not possible to extend it over all the land that needs it, nor is its efficiency necessarily as great as that depicted in the foregoing sketch. Yet aerial fire patrol is far swifter than the old ground patrol methods. It compares with them as do the modern city systems of fire-alarms and motor equipment with the bucket-brigades of medieval times.
Forest fires may begin spontaneously, as the result of lightning, or through the carelessness of man. The last factor is to some extent controllable. Education and legislation have combined to curtail smoking in the forest, to prevent burning of brush and rubbish in vulnerable areas at certain times, to check sparks from trains and so forth. In all organized timber limits where the fire hazard is scientifically predictable, where lofty observation towers overlook miles of forest land, where equipment for fire-fighting is posted at vital points, and where gangs of men are available for quick transport over bush roads, fires can be located and checked with reasonable efficiency. But where rangers are restricted to patrols by waterways, aircraft are an invaluable ally.
In the early days of aerial fire patrol in Canada, surplus wartime craft were used, irrespective of their suitability. They did good work, but they were not economical. The Ontario Provincial Air Service had virtually to rebuild its flying boats every winter.
Individual Designs for Specialized Work
Since then Canadian designers have modified various machines, and certain types now developed are suitable for forestry use. Such machines must be adaptable for skis in winter and floats in summer, be capable of taking off from and alighting on small lake surfaces, be sturdy and have good reserve lift. If, however, they are to have all these qualities, they cannot be cheap. Many foreign commercial aeroplanes have been adapted for such work, and for the peculiar Canadian conditions generally. It is inevitable, however, that aircraft design and manufacture should, on a small scale, develop within the country to serve this broad and highly specialized market.
Aircraft have done far more for Canada’s forests than guard and fight against fire. Experiments and field work have proved the value of air photographs for forest surveys. Already over 100,000 square miles of forests have been classified from air photographs and 132 maps prepared for various projects in different provinces. Air surveys have proved as accurate as expensive ground surveys. For mapping and estimating timber they have reduced ground work to a minimum and reduced the time required to produce an estimate.
Air photography, which has been used with such remarkable success in Canada for the preparation of topographic maps, now permits a minute examination of timber holdings and is being used to prepare forest inventories. The estimating of timber stands from the air is a science which is rapidly advancing through research instituted and developed by the Canadian Forest Service. Methods of determining the heights of trees have been developed by measuring their images or shadows in air photographs.
GOVERNMENT AMPHIBIAN FLYING BOAT used during the aerial mapping of areas of central and northern Canada, in the front cockpit is the photographer with his camera; next to him is the navigator who is in command of the aircraft. The pilot is next to the navigator and the mechanic is behind him.
Equipped with air photographs and a stereoscope, a woods foreman can obtain a clear picture of the area in which operations are to be conducted. The picture thus obtained enables him to lay out to the best advantage logging units and cutting areas, sites of dams and camps and logging roads, without the necessity of a preliminary survey of the region.
Where a timber-stand analysis rather than a topographic map is required, it has been found that photographs taken at an angle of about 40 degrees below the horizontal provide more detailed forest information than the usual vertical photograph and are more satisfactory than the ordinary obliques. New methods and instruments must still be developed to answer fully the requirements of forestry. In this connexion the Royal Canadian Air Force has done invaluable work.
Not only have over 100,000 square miles of Canada’s timberlands been accurately mapped through aerial survey, but also an area of forest- four times as large has been photographed and 700,000 square miles have been mapped altogether.
Until mapping by the use of aerial photographs was possible Canada did not have a truly representative national map, as so much of the area was impossible to cover economically by ordinary ground methods. About a fifth of the country was settled, and four-fifths had yet to be explored and mapped. The task ahead of the aerial surveyor seemed endless.
In forty years roughly a quarter of a million square miles had been mapped conventionally; when aeroplanes were used an almost equal area was mapped in the first five years from about 1922. When air-mapping overlapped with previous maps important corrections had to be made.
The first experiments in the hinterlands were in the mining areas of Manitoba known as The Pas, where 800 lakes were added to existing maps and countless rock exposures revealed to guide the movements of prospectors and geologists. On many map sheets as many as two thousand lakes were added.
There were foolish predictions at first that aerial photography would eliminate ground surveys entirely. Experience has proved that the two must work closely together, the one being complementary to the other.
Forest Mapping
Aerial photography aided the forester. It mapped timber according to types of growth and enabled cutting to be directed at the most productive and accessible areas. Fire prevention patrols were arranged in the most valuable areas and fire-fighting was directed in harmony with the natural features of the landscape. Aerial photography also determined the placing of camps and mills. In one season alone 35,000 square miles of forest land were mapped.
Aerial photography aided the engineer in establishing water power stations and in determining sites for storage areas. Under a proper stereoscope aerial photographs reveal contours with great accuracy and clarity, and flood-lines can be easily traced. This revelation has enabled the engineer to produce with greater speed and accuracy than before his estimates of volume, head and flow of water from vast and inaccessible watersheds.
The demand upon the skill of the pilot of the aeroplane is such that, during the photographic days, which may number only twenty-five or thirty in a season, he has to fly his machine at a given altitude and keep it there. He must fly in a straight line over unmapped country, keep the aeroplane level, on an even keel and at a constant speed (see the chapter on “Air Photography”).
Thus do the aviators and aerial surveyors give us a new vision of the lands and forests that are Canada. It is essentially a peaceful vision. It is a panorama of beauty and serenity, of great resources and of great enterprise. It is not as sophisticated in an aeronautical sense as in other lands. There are as yet no great fleets of fighting machines and bombers, few aircraft capable of great speeds, and few that fly great numbers of people from city to city. Developments of the Trans-Canada system during 1937 and 1938 have made a slight change; but on the whole the outlook of aviation in Canada is fresh and natural, seeking always an opening to serve its country in peace and prosperity as a new, exciting and vital means of transport.
“AUTOGIRO” AIRCRAFT DIRECTING FIRE-FIGHTING. The slow-flying abilities of “Autogiro” aircraft have been put to good use in fighting forest fires. By means of short-wave radio the pilot in the aircraft is able to maintain continuous contact with the men on the ground. This photograph was taken in New Jersey; the United States as well as Canada employs aircraft for fire-patrol work.
