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Home , Fire ecology, Jack pine

Proceedings: 10th Tall Timbers Conference 1970

The Role of Fire in the Ecology and of Jack

J. H. CAYFORD Program Coordinator, Silviculture Canadian Service Department of Fisheries and Forestry

OF the nine native Canadian , jack pine (Pinus banksiana Lamb.) is the most widely distributed. Although once scorned as a weed it is now regarded as an important com­ mercial species and is currently utilized for a variety of products including , rough construction timber, boxes and crates, mine timbers, railway ties, hydro and telephone poles, and posts. It has also been marketed for Christmas , but is not very well suited for this use. In the range of jack pine extends from Nova Scotia and , through , Ontario and the three Provinces to northern and the Mackenzie River valley in the Northwest Territories (Sterrett 1920, Collingwood 1938, Rudolf 1958, Hosie 1969). In northwestern its range overlaps that of lodgepole pine ( var. latifolia Engelm.); many of the trees in this area have hybrid characteristics (Moss 1953, Critchfield and Little 1966). In Canada the greatest concentration of jack pine is in the Kenora and Rainy River dis­ tricts of western Ontario; secondary concentrations occur in the

221 J. H. CAYFORD

Algoma district of Ontario and north of the prames in Manitoba and Saskatchewan. In addition, an area of medium concentration occurs in the interior of central Quebec (Halliday and Brown 1943). Yeatman (I 967) has reviewed the biogeography of jack pine and has concluded that modern populations are probably derived from one extensive glacial refugium in eastern cen­ tered in the Appalachian Highlands. In the the species is most abundant in the Lake States-in central and Wisconsin and in northeastern . It is also found in and locally in New Hampshire, Vermont, New York, Illinois and . The range of jack pine has not been appreciably extended by planting; however, there are records of on the sandhills of Nebraska and on strip­ mined areas in the Central and Northeastern States (Rudolf 1958). Jack pine occurs in areas characterized by warm to cool summers, very cold winters, and low precipitation. Within its natural range, average January temperatures range from -20 to 2SOF, average July temperatures from 55 to 72°F, and average annual precipitation from 10 to 30 inches (Rudolf 1958). Jack pine is capable of growing on the driest and poorest sites within its range and one of its outstanding virtues is its ability to produce merchantable stands where other species can scarcely sur­ vive. These sites are the characteristic jack pine sand plains which are dry, coarse to meduim sands developed on glacial outwash, morainic, aeolian, and beach deposits (Fig. 1) (Cheyney 1942, Eyre and LeBarron 1944, Wilde, Wilson and White 1949, Mueller­ Dombois 1964, Jameson 1965). In addition to its occurrence on dry sands, jack pine is also found on fresh to somewhat moist sandy-loam, loam and clay-loam of till, lacustrine and alluvial origin; on fresh to moist sands of outwash, morainic or beach origin (Fig. 2); and on relatively thin soils overlying rock outcrop. However, it is rarely found on wet, poorly drained soils (Rudolf 1958, Cayford, Chrosciewicz and Sims 1967). Best growth of jack pine occurs on fresh to somewhat moist loams; in northern Quebec, empirical yield tables show volumes of 37 cords per acre on fresh to somewhat moist, loam tills, as com­ pared with 22 cords on dry outwash sands (Bedell, Brown and

222 FIG.!. Jack pine stand on a dry sandy site in Manitoba.

MacLean 1953). In Manitoba, Bella (I 968) has prepared empirical yield tables for five sites described by Mueller-Dombois (1964). Merchantable volumes at age 60 years ranged from 16 cords on dry sands to 25 cords on fresh sands, and to 32 cords on moist sands. In Saskatchewan, Jameson (1965) reported highest productivity of jack pine on fresh, loam to clay-loam tills, and on fresh sandy-loam to loam soils of lacustrine or alluvial origin; intermediate productivity on dry and fresh sands, generally of outwash origin, and lowest productivity on very dry sands usually of aeolian origin. Although jack pine is most commonly found in pure even-aged stands, it is also frequently found in mixture with other species. Its most common tree associates in the Boreal Region include trembling aspen (Populus tremuloides Michx.), white birch (Betula papyrifera Marsh.), white spruce ( (Moench) Voss, black spruce ( (Mill.) BSP., and balsam fir (Abies

223 FIG. Z. Jack pine stand on a moist sandy site in Manitoba.

balsamea (L.) Mill.; in the Great Lakes-St. Lawrence Forest Region additional associates include northern pin oak (Quercus ellipsoidalis E. J. Hill), bur oak (Quercus macrocarpa Michx.), red pine (Pinus resinosa Ait.) and eastern white pine (Pinus strobus L.) (Rudolf 1958, Cayford, Chrosciewicz and Sims 1967).

THE ROLE OF The role of fire as a factor in the ecology of North American , and in particular the boreal forest, has been well documented by numerous investigators over the past century and indeed Komarek (1968) has recognized this forest as a lightning fire bio-climatic region. Kayll (1968) has specifically reviewed the role of fire in the Canadian boreal forest and has concluded that there is little doubt that it has always been a characteristic feature. In particular, he cited

224 FIRE AND JACK PINE reports by Bennett (1960) and Kourtz (1967) who provided defini­ tive information on the occurrence of lightning . Kiil and Chrosciewicz (1970) have observed that wildfire has been the single most important disturbance in the temperate forests of North America, and report that nearly 2.5 million acres of forest burned annually in Canada between 1957 and 1966. have been particularly extensive in the boreal forest where jack pine, lodge­ pole pine, black spruce, trembling aspen, and white birch are de­ pendent to a great extent on fire for their reproduction. In north­ eastern Minnesota Heinselman (1969) has undertaken a detailed forest history study in typical northern forest and has found that nearly all forest stands have been burned one to several times in the last 300 to 400 years and that fire has been the principal cause of forest renewal.

SILVICAL CHARACTERISTICS Cone Production:-The silvical characteristics of jack pine make the species ideally suited to regenerating after wildfire. Undoubtedly the most important characteristic is its serotinous cones which are found over most of the range and which remain on the tree for many years (Eyre and LeBarron 1944); the cone scales are held together with a resinous bonding material that melts at about 122°F (Cameron 1953). Accordingly, large numbers of seeds are retained on living trees; up to 300,000 to 400,000 cones per acre have been reported in a mature Ontario stands (Noakes 1946) and 74,000 to 130,000 in Manitoba (Bruce and Sims 1970). Roe (1963), in summarizing the results of a number of studies in northern Minnesota, reported 13,000 cones per acre in a 40-year old unthinned stand and 29,000 in a thinned stand of the same age. As a cone may yield up to 25 viable seeds and as there are 131,000 seeds per pound (Anon. 1948), it is evident that several pounds of seed may be present per acre in a jack pine stand. Cone Opening and Seed Dissemination:-Natural wildfires in jack pine are normally severe and they frequently crown; such fires are destructive and cause nearly complete mortality (Chapman 1952, Mitchell 1954). Even when jack pine stands are burned,

225 J. H. CA YFORD

the cones are rarely ignited; most of them are, however, opened by the heat produced by the fire. Early investigators (Eyre 1938, Eyre and LeBarron 1944) reported that seed was not damaged by wildfire, because of insulation afforded by the thick cone scales and that following fire, large quantities of seed were disseminated. In detailed studies of the effects of high temperatures on seed viability, Beaufait (1960 b) found that viability of seeds was not adversely affected when cones were exposed to 900°F for 30 seconds; at 700°F viability did not decrease until cones were exposed for a 3-minute interval. Beaufait also found that seeds unprotected by cone scales demonstrated an ability to remain viable until the wings ashed and seed coats cracked; this occurred following exposure to 700°F for between 10 and 15 seconds. It is thus evident that jack pine seeds are very heat tolerant and that the cones themselves pro­ vide considerable protective insulation.

Seedbed Conditions :-Requirements for seed and early seedling growth are ideally created by wildfire. Mineral , the pre­ ferred seedbed because of favourable moisture conditions, is exposed, vegetative is minimized, partial shade is provided by the dead standing trees, and increased sunlight results in maximum seed­ ling growth (Eyre and LeBarron 1944). It is also probable that a temporary fertilization is effected; Ahlgren (1959 a, 1959 b, 1960, 1970) has measured higher concentrations of nitrates, ammonia, pot­ ash, phosphates and calcium in the upper soil levels' on burned than on comparable unburned areas. These higher concentrations were un­ doubtedly caused by the release of nutrients from ash and prevailed for at least 5 years after fire. Ahlgren (1959 b) has also found that oats and sunflowers, grown under controlled greenhouse conditions, were 20 to 65 percent heavier when grown on soil from burned land than from comparable unburned land. However, the high nutrient concentrations in the ash after burning may be toxic to germinating seedlings before sufficient leaching and dilution by rain­ fall has occurred (Ahlgren 1959 a). In northern Saskatchewan, fol­ lowing wildfire in mature jack pine-black spruce stands, Scotter (1963) found a decrease in total exchange capacity, an increase in

226 FIRE AND JACK PINE exchangeable calcium, an increase in available phosphorus, and a de­ crease in soil acidity on burned areas. Many of the beneficial effects of fire on germination and seedling growth are short-term; however, they are operative through the critical period of seedling establishment.

NATURAL JACK PINE REGENERATION Because jack pine is so well adapted to regenerating after fire, it is no surprise that most of our present-day stands have originated following wildfire. When pure stands are burned, they generally regenerate to jack pine and as early as 1911 Ellis reported that in Ontario jack pine "grows chiefly on burnt-over areas-the extensive stands of it to be found . . . are due, to a large extent, to past fires. This characteristic of occupying brule country it shares with aspen, with which it is frequently associated." Ellis (1911) further observed that 10 days after a fire had burned a jack pine stand, seedlings were growing in "scores of thousands to the acre" over large areas. It should be noted, however, that adequate regeneration does not always follow wildfire in jack pine stands; in Saskatchewan, Kabzems and Kirby (1956) have found that light soils may, in some instances, be reduced to a desert of drifting sand or taken over by a dense growth of grass and brush. Similarly, Graftstrom and Hansen (1962) have noted that some wildfires in Minnesota have encouraged conver­ sion to brush and low value hardwoods. A number of investigators have studied the factors affecting re­ generation and its variability following wildfire in jack pine. Ahlgren (1959 a) found in Minnesota that good regeneration occurred on areas where fire had reduced the organic layer to a depth of 1 to 2 inches. There, the layer of ash and organic matter retained sufficient moisture for germination. Where the burn was light, leaving a 3 to 6-inch organic layer, little or no regeneration was established. Simi­ larly in Saskatchewan, Jameson (1961) found intensity of fire to be an important factor affecting jack pine regeneration, while in Mani­ toba, Cayford (1963) observed better regeneration on northerly and easterly aspects than on southerly and westerly aspects. Other factors that may affect jack pine regeneration density and growth are

227 J. H. CAYFORD weather conditions after the fire, stand density, seed supply in serotinous cones, and site (Ahlgren 1959 a, 1960, Cayford 1963, Graftstrom and Hansen 1962). In the Lake States, wildfires have been responsible for converting many mixed red and white pine stands to jack pine. In the early part of the century, jack pine was not extensively used and only the more valuable red and white pines were harvested. Slash fires were very prevalent and they favoured jack pine by killing advance reproduc­ tion and the few remaining seed trees of white and red pine, while releasing seed from the scattered jack pine that were usually present. Consequently, extensive jack pine stands developed where originally there had been stands of red and white pine (Wackerman, Zon and Wilson 1929, Eyre 1938, Cheyney 1942, Eyre and LeBarron 1944, Kilburn 1960, Cooper 1961). Regeneration following slash fires in clear-cut jack pine stands has usually been inadequate because of the destruction of cones in the slash. Fires burning through such areas invariably consume the un­ opened cones in the slash and because all merchantable trees are cut, there is no other seed source. In the few areas where cones are not destroyed, the fire is usually not sufficiently hot to prepare a suitable seedbed (Eyre 1938, Eyre and LeBarron 1944, Chrosciewicz 1959, Van Wagner 1966). In partially cut jack pine stands, regeneration following fire is usually satisfactory, provided an adequate seed source is present. In Michigan approximately 75 cone-bearing jack pine trees, well distributed over an area, were required to fully re­ stock an area (10)1. In Saskatchewan a 70-year-old residual stand of 60 trees per acre was sufficient for adequate stocking (Jameson 1961); in Manitoba 20 dominant seed trees, plus approximately 150 unmerchantable 1 to 3-inch trees, provided adequate seed for ade:­ quate stocking (Cayford 1963), while in Minnesota 10 seed trees, averaging 12 inches in diameter, provided 15,000 to 20,000 seedlings per acre (Ahlgren 1959 a). A second fire burning through a jack pine sapling stand will usually kill all seedlings, and because of a lack of seed source, the

'Unpublished reports and personal communications are cited by number and listed at the end of the text.

228 FIRE AND JACK PINE burned areas may revert to brush or grass (Eyre and LeBarron 1944). However, if a second fire does not occur until after the jack pine saplings bear seed, which may be at ages less than 10 years, then the only adverse effect will be to retard stand development by a few years. Ahlgren (1959 a) has observed that 5 to 7-year old jack pine begin to develop cones and that 80 percent of the seed from these young post-fire trees were viable.

THE ROLE OF PRESCRIBED FIRE

RESEARCH PROGRAMS initially became interested in jack pine regeneration silviculture in the late 1930's when it became evident that jack pine stands would not regenerate adequately unless special silvicultural practices were undertaken (Eyre 1938). Specific examples of re­ generation failures were cited by Eyre and LeBarron (1944) who surveyed nine representative cut-over areas in the Lake States and found adequate regeneration on only one. In the same publication, Eyre and LeBarron (1944) concluded that if jack pine was to be naturally regenerated, then stands should be clear cut, mineral soil seedbeds prepared, and cone-bearing slash scattered on or close to the mineral soil seedbeds to assure prompt opening of cones and dispersal of seeds. Subsequent research programs in the Lake States in the 1940's were concerned with the development of suitable techniques utilizing a variety of machines for seedbed preparation. In the late 1940's the first research work was undertaken in the use of prescribed burning (Fig. 3-6) for jack pine regeneration. A number of spring and fall burns were undertaken in central Ontario between 1949 and 1956. Burning was carried out for the purpose of preparing suitable seedbeds for jack pine germination with seed to be obtained from either seed trees reserved from cutting 6r by sub­ sequent broadcast seeding. Results of these trials reported by Chrosciewicz (I959) indicated that jack pine could be successfully regenerated by using fire, provided that the depth of humus was substantially reduced, thus creating seedbeds that were suitable for seedling establishment. However, some trials were unsuccessful be-

229 J. H. CAYFORD

FIG. 3. A clear-cut jack pine stand.

FIG. 4. A head fire during a prescribed burn trial in Manitoba. 230 FIRE AND JACK PINE

FIG. 5. A back fire during a prescribed burn trial in Manitoba.

FIG. 6. A clear-cut jack pine stand which has been prescribed burned.

231 J. H. CAYFORD cause the burns were carried out when the humus was too moist. These trials also indicated that a severe slash fire hazard could be eliminated by burning at low drought and danger indexes (Williams 1958) and that cones in the crowns of seed trees could be opened with a good head fire. Later studies in the same region involved summer burning under various drought conditions followed by broadcast seeding the following spring. Results from this work indi­ cated that the extent of reduction of the humus layer was correlated with the drought index at the time of burning but that, in general, stocking with jack pine was successful. Third-year stocking based on one-milacre quadrats was 60 percent on one area and 80 to 99 percent on the other 10 areas (Chrosciewicz 1967, 1968, 1970). Also in Ontario, Van Wagner (1966) burned three cut-over jack pine areas under three degrees of hazard-moderate, high and ex­ treme. All three fires levelled the slash but only on the area burned under extreme conditions was the humus sufficiently dry for burning to prepare good seedbeds. In Quebec the International Paper Company carried out pre­ scribed burning trials between 1967 and 1969 in cut-over jack pine stands. The burns were conducted in the spring when the soil was still frozen; they did not prepare seedbeds because only the surface of the humus was burned. However, ~osts were reduced by 25 percent on burned areas because of elimination of much of the slash ( Vezina and Robitaille 1970). Between 1957 and 1959 a series of prescribed burns were held in cut-over jack pine stands in Michigan (Beaufait 1960 a, 1961, 1962). The first two burns were conducted in slash on areas from which all merchantable jack pine had been harvested and they demonstrated conclusively that cones in burned slash did not provide a satisfactory seed source. Later burns indicated that satisfactory regeneration could be obtained by retaining 12 to 50 seed trees per acre and by burning slash under sufficiently dry conditions to ensure a hot fire. On the Superior National Forest in northeastern Minnesota, the Quetico-Superior Wilderness Research Centre has conducted several prescribed burns in cut-over stands and vegetational development has been followed for up to 9 years after burning (Ahlgren 1970). Successful jack pine regeneration has been obtained both by burning

232 FIRE AND JACK PINE clear-cut stands and broadcast seeding, and by burning in conjunc­ tion with the reservation of seed trees during . Ahlgren (1970) suggested that these treatments would yield consistent results in other jack pine forests under similar conditions. In 1964 a program was begun in Manitoba to determine whether prescribed burning could be used in cut-over jack pine stands to prepare them for natural or artificial seeding or for planting. Other objectives were to determine optimum conditions for burning, to study fire behaviour and to study the ecological effects of fire (Adams 1966, Cayford 1966, Foster et al. 1967). Final definitive re­ sults from this work are not yet available, but preliminary results indicate that seed tree areas were inadequately stocked; similarly, results of broadcast seeding have been unsuccessful. More promising initial results have been obtained from seed-spotting and from ­ ing bare-root nursery stock (Cayford 1966). There are indications that these poor results reflect the hot and dry conditions prevailing on the burned, sandy seedbeds and there is some evidence to suggest that by delaying artificial regeneration attempts, the environments will be sufficiently moderated to enhance regeneration possibil­ ities (9). As a result of the research programs that have been carried out in the use of prescribed burning there is considerable information avail­ able in the literature concerning procedures for burning (Chro­ sciewicz 1959, 1967, Williams 1960, Beaufait 1962, Adams 1966, Van Wagner 1966, Foster et al. 1967, Ahlgren 1970, Sando and Dobbs 1970. Various ignition patterns have been recommended by different investigators, but most have emphasized the use of headfires follow­ ing the burning of a safety strip on the extreme downwind side of the treatment area (Beaufait 1962, Adams 1966, Foster et al. 1967, Ahlgren 1970, Sando and Dobbs 1970). Headfires are of value in rapid slash disposal, in opening cones in seed trees, in minimizing costs, and when are discontinuous or sparse. However, they are more difficult to control than backfires, which may result in more humus reduction (Martin and Davis 1961). Area ignition, in­ volving the simultaneous lighting of several fires in the centre of the area to be burned, coupled with the development of a strong

233 J. H. CA YFORD convection column, although reqmnng considerable knowledge of fire behaviour, can be an effective method (Sando and Dobbs 1970). Various other aspects of planning, preparing and executing pre­ scribed burns are well covered by Sando and Dobbs (1970).

OPERATIONAL PROGRAMS Having discussed in some detail the various research programs in jack pine prescribed burning, one might get the impression that burning is a commonly-used technique in managing jack pine. How­ ever, for a number of reasons, operational application has not really kept pace with research and use of prescribed burning is still es­ sentially in the experimental or trial and error stage. In order to assess the current situation with respect to operational programs involving the use of prescribed fire, I have carried out a survey of several agencies concerned with jack pine management. The various replies from this survey provide the information syn­ thesized below. Very little prescribed burning is currently undertaken to prepare seedbeds for either natural seeding from seed trees or for direct seed­ ing. Prescribed burning trials to naturally regenerate jack pine in Ontario have been tried (3), but with varying degrees of success. Generally, results have been poor, except where an adequate seed source has been available in good quality residual trees following harvesting. However, because of improved utilization, this technique is now rarely used. In the Lake States attempts to leave seed trees and prescribe burn to open the serotinous cones have generally been un­ successful and consequently the method has relatively little current application (2). However, in Minnesota, a small amount of burning is currently undertaken in conjunction with direct seeding. Practically all of the operational prescribed burning is carried out under low and moderate fire hazard for the dual purposes of reduc­ ing fire hazard and for preparing sites for either planting or for subsequent mechanical seedbed preparation. In Canada, programs are underway in New Brunswick, Ontario, and Manitoba; in 1968-69 in Ontario only 600 of 25,100 acres prepared for jack pine regenera­ tion were prescribed burned (3), while in Manitoba only about 500

234 FIRE AND JACK PINE of 5,000 acres are annually burned (8). In New Brunswick, burning is done in the early spring and is followed directly by planting (6); in Ontario and in Manitoba burning is normally followed by me­ chanical site preparation and seeding or planting (3,8). Similarly, in the Lake States, prescribed burning of jack pine cut-overs accounts for only a relatively small amount of the area annually site prepared and most of the burns are subsequently reforested with red pine (2, 4,7,11). Prescribed burning is sometimes carried out in jack pine stands for purposes other than regeneration. On the Huron National Forest in Michigan burning has been undertaken in jack pine stands for the purpose of preserving the of Kirtland's warbler (Dendroica kirtlandi) (Miller 1963, Buckman 1964). This rare species is found only in dense homogenous blocks of jack pine varying from 5 to 15 feet in height and interspersed with small openings. Manage­ ment of the pine stands, to preserve the warbler, combines short cut­ ting cycle management, prescribed burning and planting. Fire may also be used on jack pine sand plains to increase produc­ tivity of wild ( spp.) and also to increase popu­ lation of the sharp-tailed grouse (Pedioecetes phasianellus) (Vogi 1967, Smith 1968, 11).

ALTERNATIVES TO PRESCRIBED FIRE From the foregoing it is evident that prescribed burning is little used in jack pine regeneration silviculture and alternative methods are normally employed to regenerate this species. Jack pine stands are generally relatively simple and easy to regen­ erate after logging. A successful treatment must ensure firstly that full or nearly full light is available for seedling development, secondly that suitable seedbeds are available for seed germination and seedling survival and, thirdly that appropriate regeneration techniques (e.g. artificial or natural seeding, planting) are employed. Clear cutting is the normally accepted method for harvesting jack pine and consequently the primary requirement of light is attained in practically all jack pine cutovers. Near the southern limit of its range, light shade may be beneficial to seedling survival and jack pine is com-

235 J. H. CAYFORD monly harvested in Michigan under a 2-cut shelterwood system (Caveney and Rudolph 1970); in a study of 42 such stands it was found that optimum residual basal area was between 30 and 40 square feet per acre. Suitable seedbeds for jack pine are mineral soil, thin humus over mineral soil, or ash-covered mineral soil; these conditions may be achieved by mechanical means, by prescribed burning or by a com­ bination of the two. As an alternative to prescribed burning, most agencies mechanically prepare cut-over jack pine sites, using a wide variety of machines (3,5,7,8,11). Essentially, two basic types of equipment are employed: (a) front-mounted equipment including the conventional bulldozer blade, rock and root rakes, "V" ploughs, "Young" scarifying teeth, and (b) pulled equipment including the S.F.I. Swedish scarifier, Fleco or Marden drum brush choppers, fireline ploughs and disks. In addi­ tion, various types of drags have been designed and developed by the Ontario Department of Lands and Forests, including those con­ structed with ship's anchor chains or tractor pads or combinations of both, or finned steel drums or barrels of various sizes used in sets and sometimes in combination with tractor pads or anchor chain units (Fig. 7 and 8) (Morawski 1966, Brown 1966, Hall 1970). In some instances site preparation is carried out simultaneously with planting, using various types of planting machines generally equipped with scalping blades. This treatment is restricted to areas where slash is very light as on old non-regenerating burns or cuts (8). Following site preparation, regeneration is obtained from cone­ bearing slash, by aerial or ground seeding, or by the planting of nursery stock or containerized seedlings. In Ontario all methods are employed (Scott 1966, 1970, MacKinnon 1968, 1970, Stevens 1970); in 1968-69, 30 percent of the area regenerated to jack pine was by natural regeneration, 25 percent by seeding, 26 percent by planting nursery stock, and 18 percent by planting tubelings (3). In Manitoba, Saskatchewan and New Brunswick most regeneration is by planting; seeding and container planting are undertaken on a. limited scale (6,8). In the Lake States site preparation on many of the cut-over jack pine sites is followed by planting of red pines, however, limited areas are regenerated to jack pine from cone-bearing slash or by

236 FIRE AND JACK PINE

FIG. 7. Anchor chain-tractor pad scarifier.

FIG. 8. Finned-drum scarifier.

237 J. H. CAYFORD planting of nursery stock; direct seeding and planting of contain­ erized stock are still mostly in the experimental stage (AIm and Schantz-Hansen, 1970, 1,2,4,5,11).

DISCUSSION It has been shown that a number of research foresters have in­ vestigated the use of prescribed burning as a technique for regenerat­ ing cut-over jack pine stands and, in general, results have been very promising. However, it has also been shown that prescribed burning currently plays a relatively insignificant role in the silviculture of jack pine and it is apparent that the results of research have not been translated into general practice. I believe that there are several reasons why prescribed burning has not found more widespread acceptance by forest managers as a tool in the silviculture of jack pine and some of these reasons are discussed below. There seems little doubt that the forestry profession's major pre­ occupation with fire prevention has had, psychologically, an adverse and delaying effect on the use of fire in forestry for any purpose. Many forest administrators and practicing foresters are still reluctant to light a fire when one of their major responsibilities is often to con­ trol and suppress wildfire. It is also important to note that every pre­ scribed burn involves a certain risk, as there is always the danger that one will escape and cause extensive damage. However, the risk of escape will be reduced as more insight is gained about the behaviour of prescribed fires under different conditions. More reliable fire weather forecasts, better use of drought indicators, and more effective ignition techniques will, no doubt, also reduce the probability of fire escapes (Kiil and Chrosciewicz 1970). Another important factor mitigating against the use of prescribed burning in jack pine is the availability of alternative silvicultural methods. Especially noteworthy in this regard is the wide variety of mechanical equipment available for site preparation on all but very rocky sites. Not only does mechanical site preparation avoid the risk associated with prescribed burning, but it provides more flexibility with respect to timing. Sites can be prepared mechanically virtually any time from spring to fall, whereas prescribed burning can be un-

238 FIRE AND JACK PINE dertaken only under very specific weather conditions. In fact, Williams (1960) has reported that in certain Canadian localities prescribed burning for seedbed preparation can only be carried out on a few days each year and the range may be from 0 to 20 days. Further, mechanical site. preparation requires relatively little labour, while prescribed burning is a labour-intensive treatment. Valid comparative costs between burning and mechanical site preparation are not available, but there are indications that the cost differential may not be of sufficient importance to be a deciding fac­ tor in arriving at a decision whether to burn or to mechanically pre­ pare sites for regeneration. In Ontario, MacKinnon (1968) reported that the average cost for mechanical site preparation was $13 per acre; Scott (1970) reported the following costs for different site preparation methods: tractor pads and anchor chains, $12.20; finned barrels, $16.00; detachable teeth, $17.30; blades, $13.00. In extensive trials in Ontario using the S.F.1. scarifier, costs of scarifying boulder­ free sand flats, with light to medium jack pine slash, were $7.21 per acre (Anon. 1970). Little information is available on the costs of prescribed burning, but Adams (1966) quoted costs of $5.00 to $16.00 for experimental 18 to 51 acre burns in Manitoba and sug­ gested that average costs might be reduced to about $5.00 per acre. It is also evident that there are still certain technical problems to be solved in connection with the use of prescribed burning. Cer­ tainly, results obtained to date in Manitoba research programs have not been sufficiently satisfactory to justify operational programs, and it is possible that too extreme conditions may be created by burning. Similarly, certain of the operational seed-tree burning trials in Ontario and in the Lake States have not given satisfactory results, even though results from research burns have been promising. These results indicate the difficulty in extrapolating results obt:

239 J. H. CAYFORD cern for the quality of the envirohment imposes a major limitation on any prescribed burn. In Washington, apple and pear growers have complained that from prescribed burning prevents fruit from ripening, and hunters have complained that the fires chase away game (Oberle 1969). Consequently, forest fire researchers are at­ tempting to develop burning methods which can minimize the threat of impaired air quality from forest burning. At the same time, alter­ native methods of slash burning such as chemicals to hasten de­ composition, chippers, portable burners, and mechanical crush­ ers are being studied (Oberle 1969, Murphy, Fritschen and Cramer 1970). It is significant to note that prescribed burning has been seriously curtailed in Scandinavia in recent years. Reasons for this include the occurrence of a fungus (Rhizina undulata) on burned areas, a reduc­ tion of growth some years after burning, and the labour-intensive nature of prescribed burning. It is my opinion that the role of prescribed burning in jack pine management will continue to be relatively minor. I believe that most burning will continue to be undertaken at relatively low hazards with the primary objectives to reduce fire hazard and to prepare areas for further site preparation treatment. Indeed, as utilization standards improve and as alternative slash disposal methods are de­ veloped, the necessity of burning for fire-hazard reduction will decrease. It is conceivable that prescribed burning will ultimately find its most important application in wilderness and park areas which are managed primi1rily for purposes other than for timber production and where cutting of trees and the mechanical preparation of sites will be restricted.

LITERATURE CITED Adams, J. L. 1966. Prescribed burning techniques for site preparation in cut-over jack pine in southeastern Manitoba. Pulp Paper Mag. Can., Wood!. Rev., December, 1966. Vol. 67, No. 12. pp. WR-574-WR-584. Ahlgren, Clifford E. 1959 a. Some effects of fire on forest reproduction in north­ eastern Minnesota. J. Forestry 57: 194-200. --. 1959 b. Vegetational development following burning in the northern coniferous' forest of Minnesota. Proc. Soc. Amer. For., San Francisco, Calif. 1959. pp. 21-22.

240 FIRE AND JACK PINE

---. 1960. Some effects of fire on reproduction and growth of in northeastern Minnesota. Ecology 41:431-445. ---. 1970. Some effects of prescribed burning on jack pine reproduction in northeastern Minnesota. Univ. Minnesota, Agr. Exp. Sta., Misc. Rep. 94, Forestry Series 5. 14 pp. AIm, A. A. and R. Schantz-Hansen. 1970. Planting pine tubelings in Minnesota. J. Forestry 68:353-357. Anon. 1948. Woody-plant seed manual. U.S. Department of , Misc. Publn. 654. 416 pp. ---. 1970. SFI scarifier-seeder does lightweight, low-cost job. Can. For. Ind. 90(8) :59, 61. Beaufait, W. R. 1960 a. Influences of shade level and site treatment, including fire, on germination and early survival of Pinus banksiana. Mich. Dept. Conserva­ tion, For. Div. 79 pp. ---. 1960 b. Some effects of high temperatures on the cones and seeds of jack pine. For. Sci. 6: 194-199. ---. 1961. Crown temperatures during prescribed burning in jack pine. Pap. Mich. Acad. Sci., Arts and Letters 46:251-257. ---. 1962. Procedures in prescribed burning for jack pine regeneration. Michigan ColI. Mining and Tech., Ford For. Centre, Tech. Bull. 9. 37 pp. Bedell, G. H. D., W. G. E. Brown and D. W. MacLean. 1953. Forest site classifica­ tion and growth of the jack pine cover types in Forest Section B.7 (Quebec). Canada Dept. Resources and Development, For. Br., For. Res. Div., S. & M. 53-2. 102 pp. Bella, 1. E. 1968. Jack pine yield tables for southeastern Manitoba. Canad:; Dept. Fisheries and Forestry, For. Br., Publn. 1207. 15 pp. Bennett, W. D. 1960. Survey of lightning fire occurrences in Canada's forests- 1950 to 1959. Pulp Paper Res. Inst. Canada, Tech. Rep. 212. 9 pp. Brown, G. 1966. A modified barrel scarifier. Ontario Dept. Lands and Forests, Timber Br., Silv. Sec., SHy. Note 6. 8 pp. Bruce, N. G. and H. P. Sims. 1970. Site preparation essential to obtaining best results from jack pine cones. Pulp Paper Mag. Cart. 71 (14) :70-72. Buckman, R. E. 1964. Silvicultural use of prescribed burning in the Lake States. Proc. Soc. Amer. For., 1964, Denver, Colo. pp. 38-40. Cameron, H. 1953. Melting point of the bonding material in lodgepole and jack pine cones. Canada, Dept. Resources and Development, For. Br., SHy. Leaflet 86. 33 pp. Caveney, E. W., Jr. and V. J. Rudolph. 1970. Reproducing jack pine by the shelterwood method. Michigan State Univ., Agr. Exp. Sta., Res. Rep. 110. 11 pp. Cayford, J. H. 1963. Some factors influencing jack pine regeneration after fire in southeastern Manitoba. Canada, Dept. Forestry, For. Res. Br., Publn. 1016. 16 pp. ---. 1966. Some aspects of jack pine regeneration on prescribed burned areas. Canada, Dept. Forestry and Rural Development, For. Br., Bi-Monthly Res. Notes 22 (5) :7. ---, Z. Chrosciewicz and H. P. Sims. 1967. A review of silvicultural reseach in jack pine. Canada, Dept. Forestry and Rural Development, For. Br., Dept. Publn. 1173. 255 pp. Chapman, H. H. 1952. The place of fire in the ecology of pines Bartonia 26:39-44. Cheyney, E. G. 1942. American silvics and silviculture. Univ. Minnesota Press, Minneapolis, Minn. 472 pp. Chrosciewicz, Z. 1959. Controlled burning experiments on jack pine sites. Canada,

241 J. H. CAYFORD

Dept. Northern Affairs and National Resources, For. Br., For. Res. Div., Tech. Note n. 19 pp. ---. 1967. Experimental burning for humus disposal on clear-cut jack pine sites in central Ontario. Canada, Dept. Forestry and Rural Development, For. Br., Publin. 1181. 23 pp. ---. 1968. Drought conditions for burning raw humus on clear-cut jack pine sites in central Ontario. For. Chron. 44:30-31. ---. 1970. Regeneration of jack pine by burning and seeding treatments on clear-cut sites in central Ontario. Canada, Dept. Fisheries and Forestry, Can. For. Serv., Ontario Reg., Info. Rep. O-X-138. 13 pp. Collingwood, G. H. 1938. Jack pine. Amer. Forests 44:268-269. Cooper, Charles F. 1961. The ecology of fire. Sci. Amer. 204(4):150-156, 158, 160. Critchfield, W. B. and E. L. Little. 1966. Geographic distribution of the pines of . the world. U.S. Dept. Agriculture, For. Serv., Misc. Publn. 991. 97 pp. Ellis, L. M. 1911. Some notes on jack pine (Pinus divarticata) in western Ontario. For Quart. 9: 1-14. Eyre, F. H. 1938. Can jack pine be regenerated without fire? J. For. 36: 1067-1072. ---, and R. K. LeBarron. 1944. Management of jack pine stands in the Lake States. U.S. Dept. Agr., Tech. Bull. 863. 66 pp. Foster, W. T., G. A. Hubert, J. Cayford, W. A. Dickson and A. P. MacBean. 1967. Symposium on prescribed burning. Pulp Pap. Mag. Can., Woodl. Rev., January, WR-4--WR-18. Grafstrom, Myron D. and Henry L. Hansen. 1962. Post-fire regeneration study of the 1959 Badoura and 1960 Bemidji fires. Univ. Minnesota, Sch. For., Minn. For. Note 116. 2 pp. Hall, John. 1970. Site preparation in Ontario. In Forestry Reader, Background papers prepared for the Forestry Seminar sponsored by the Canadian Council of Resource Ministers, Winnipeg, Manitoba, Nov. 25-27, 1970. Paper 8. 4 pp. Halliday, W. E. D. and A. W. A. Brown. 1943. The distribution of some important forest trees in Canada. Ecology 24:353-373. Heinselman, M. L. 1969. Diary of the canoe country's landscape. Naturalist 20(1): 2-13. Hosie, R. C. 1969. Native Trees of Canada. 7th ed. Canada, Dept. Fisheries and Forestry, Can. For. Serv. 380 pp. Jameson, J. S. 1961. Observations on factors influencing jack pine reproduction in Saskatchewan. Canada, Dept. Forestry, For. Res. Div., Tech. Note 97. 24 pp. ---. 1965. Relation of jack pine height-growth to site in the Mixedwood Forest Section of Saskatchewan. In Forest-soil relationship~ in North American. Papers presented at the Second North American Forest Soils Conference, Oregon State University, 1963. pp. 299-316. Kabzems, A. and C. L. Kirby. 1956. The growth and yield of jack pine in Saskatchewan. Saskatchewan, Dept. Natural Resources, For.. Br., Tech. Bull. 2. 66 pp. Kayll, A. ]. 1968. The role of fire in the . Canada Dept. Forestry and Rural Development, For. Br., Petawawa For. Exp. Sta., Info. Rep. PS-X-7. 15 pp. Kiil, A. D. and Z. Chrosciewicz. 1970. Prescribed fire-its place in . In Forestry Reader, Background papers prepared for the Forestry Seminar sponsored by the Canadian Council of Resource Ministers, Winnipeg, Mani~ toba, Nov. 25-27, 1970. Paper 7. 9 pp. Kilburn, Paul D. 1960. Effects of logging and fire on xerophytic forests in . Bull. Torrey Bot. Club 87:402-405.

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Komarek, E. V., Sr. 1968. Lightning and lightning fires as ecological forces. Proc. Annual Tall Timbers Fire Ecology Conf. No.8, March 14-15, 1968, Talla­ hassee, Florida. pp. 169-197. Kourtz, P. 1967. Lightning behaviour and lightning fires in Canadian forests. Canada, Dept. Forestry and Rural Development, For. Br., Publn. 1179. 33 pp. 1\lacKinnon, G. E. 1968. Reforestation in Ontario. For. Chron. 44(1): 14-17. ---. 1970. Container planting in Ontario. In Forestry Reader, Background papers prepared for the Forestry Seminar sponsored by the Canadian Council of Resource Ministers, Winnipeg, Manitoba, Nov. 25-27, 1970. Paper 11. 6 pp. 1\1artin, R. E. and L. S. Davis. 1961. Temperatures near the ground during prescribed burning. Pap. Mich. Acad. Sci., Arts and Letters 46:239-249. 1\liller, H. A. 1963. Use of fire in wildlife management. Proc. Second Annual Tall Timbers Fire Ecology Conf., March 14-15, 1963, Tallahassee, Florida. pp. 19-30. 1\litchell, J. A. 1954. Mortality from fire in jack pine stands. U.S. Dept. Agr", For. Serv., Lake States For. Exp. Sta., Tech. Note 416. 2 pp. 1\\ora\\'ski, J. R. 1966. Site preparation methods and recommendations for equipment usage. Ontario, Dept. Lands and Forests, Timber Br., Silv. Sec., Silv. Note 8. 25 pp. 1\1oss. E. H. 1953. Forest communities in northwestern Alberta. Can. J. Bot. 31: 212-252. l\lueller-Dombois, D. 1964. The forest habitat types of southeastern Manitoba and their application to . Can. J. Bot. 42: 1417-1444. :\\urphy, James L., Leo J. Fritschen and Owen P. Cramer. 1970. Slash burning :pollution can be reduced. U.S. Dept. Agr., For. Serv., Fire Control Notes 31(3):3-5. Noakes, J. W. 1946. Effect of different methods of slash disposal on jack pine reproduction. Canada, Dept. Mines and Resources, Lands, Parks and Forests Br., Dom. For. Serv., Silv. Res. Note 78. 8 pp. Oberle, M. 1969. Forest fires: suppression policy has its ecological drawbacks. Science 165 :568-571. Roe, E. I. 1963. Seed stored in cones of some jack pine stands, northern Minnesota. U.S. Dept. Agr., For. Ser., Lake States For. Exp. Sta. Res. Paper LS-l. 14 pp. Rudolph, PaulO. 1958. Silvical characteristics of jack pine (Pinus banksiana). U.S. Dept. Agr., For. Serv., Lake States For. Exp. Sta., Sta. Pap. 61. 31 pp. Sando, R. W. and R. C. Dobbs. 1970. Planning for prescribed burning in Manitoba and Saskatchewan. Canada, Dept. Fisheries and Forestry, Can. For. Serv., For. Res. Lab., Winnipeg, Liaison & Services Note MS-L-9. 18 pp. Scott, J. D. 1966. Broadcast seeding by air. Canadian Pulp Pap. Assn., Woodlands Sec., W.S. Index 2411 (F-2). 13 pp. ---. 1970. Direct seeding in Ontario. In Forestry Reader, Background papers prepared for the Forestry Seminar sponsored by the Canadian Council of Resource Ministers, Winnipeg, Manitoba, Nov. 25-27, 1970. Paper 13. 9 pp. Scotter, G. W.·1963. Effects of forest fires on soil properties in northern Saskatche­ wan. For. Chron. 39:412'-421. Smith, D. W. 1968. Surface fires in northern Ontario. Proc. Annual Tall Timbers Fire Ecology Conf. No.8, March 14-15, 1968, Tallahassee, Florida. pp. 41-54. Sterrett, W. D. 1920. Jack pine. U.S. Dept. Agr., Bull. 820. 47 pp. Stevens, W. C. 1970. Hand and machine in northern Ontario. In Forestry Reader, Background papers prepared for the Forestry Seminar sponsored by the Canadian Council of Resource Ministers, Winnipeg, Mani­ toba, Nov. 25-27, 1970. Paper 1OA. 3 pp. Van Wagner, C. E. 1966. Three experimental fires in jack pine slash. Canada, Dept. Forestry, Publn. 1146. 22 pp.

243 J. H. CA YFORD

Vezina, Paul-E. and Lise Robitaille. 1970. Etude des methodes de coupe et autres traitements sylvicoles experimentes au Quebec. Quebec, Ministere des Ter­ res et Forets, Servo Recherche, Mem. 2. 372 pp. Vogl, R. J. 1967. Controlled burning for wildlife in Wisconsin. Proc. Sixth Annual Tall Timbers Fire Ecology Conf., March 6-7, 1967, Tallahassee, Florida. pp. 47-96. Wackerman, A. E., R. Zon, and F. G. Wilson. 1929. Yield of jack pine in the Lake States. Wis. Agr. Exp. Sta., Res. Bull. 90. 23 pp. Wilde, S. A., F. G. Wilson, and D. P. White. 1949. Soils in Wisconsin in relation to silviculture. Wis. Dept. Conservation, Publn. 525-49. 171 pp. Williams, D. E. 1958. Two control-burns in jack pine cut-overs. Pulp Pap. Mag. Can., Wood!. Rev., Convention Issue: 48, 50, 52, 54. ---. 1960. Prescribed burning for seedbed preparation in jack pine types. Pulp Pap. Mag. Can., Wood!. Rev., April: 194-198. Wilson, K. O. 1970. Forest fuels management, the problem and the challenge. J. For. 68:274-279. Yeatman, C. W. 1967. Biogeography of jack pine. Can. J. Bot. 45:2201-22'11.

UNPUBLISHED REPORTS AND PERSONAL COMMUNICATIONS 1. Aultfather, Wm. Minn., Dept. Conservation, St. Paul, June 30, 1970. Personal communication. 2. Benzie, John W. U.s., Dept. Agr., For. Serv., Grand Rapids, Minn., May 15, 1970. Personal communication. 3. Herridge, A. J. Ontario, Dept. Lands and Forests, Timber Br., Toronto, May 27, 1970. Personal communication. 4. Kollmeyer, Harold W. Mich., Dept. Natural Resources, For. Div., Lansing, June 26, 1970. Personal communication. 5. Michal, Terrence F. Mosinee Paper Mills Co., Solon Springs, Wise., May 27, 1970. Personal communication. 6. Redmond, R. A. New Brunswick, Dept. Natural Resources, For. Br., Frederic­ ton, Aug. 6, 1970. Personal communication. 7. Sando, Rodney W. U.S., Dept. Agr., For. Serv., St. Paul, Minn., April 3, 1970. Personal communication. 8. Waldron, R. M. Canada, Dept. Fisheries and Forestry, Winnipeg, Man., June 5, 1970. Personal communication. 9. Walker, N. R. and R. C. Dobbs. Canada, Dept. Fisheries and Forestry, Winni­ peg, Man., April 1968 and April 1969. Unpublished reports. 10. Watson, R. 1937. Jack pine in Michigan. U.S. Dept. Agr., For. Serv. Processed report. 11. Zagorski, Joseph F. Wisconsin, Dept. Natural Resources, Div. For. and Rec., Brule, July 13, 1970. Personal communication.

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