Index of Species Information

SPECIES:  Pinus sylvestris


SPECIES: Pinus sylvestris
AUTHORSHIP AND CITATION : Sullivan, Janet. 1993. Pinus sylvestris. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: [].
ABBREVIATION : PINSYL SYNONYMS : NO-ENTRY SCS PLANT CODE : PISY COMMON NAMES : Scots pine TAXONOMY : The currently accepted scientific name of Scots pine is Pinus sylvestris L. [42]. Scots pine introduced in North America are nearly all the typical variety, Pinus sylvestris var. sylvestris [61]. LIFE FORM : Tree FEDERAL LEGAL STATUS : No special status OTHER STATUS : NO-ENTRY


SPECIES: Pinus sylvestris
GENERAL DISTRIBUTION : Scots pine is the most widely distributed pine in the world. It's native range includes Scotland, Scandinavia (excluding Denmark), northern Europe, and northern Asia. It is introduced in many areas in the United States and Canada, and is naturalized in the Northeast and in the Great Lakes states [29,32,42]. ECOSYSTEMS : FRES10 White - red - jack pine FRES11 Spruce - fir FRES15 Oak - hickory FRES18 Maple - beech - birch FRES19 Aspen - birch STATES : CT DE HI IL IN IA ME MA MI MN NH NJ NY OH PA RI VT WI NB NF NS ON PE PQ BLM PHYSIOGRAPHIC REGIONS : NO-ENTRY KUCHLER PLANT ASSOCIATIONS : NO-ENTRY SAF COVER TYPES : NO-ENTRY SRM (RANGELAND) COVER TYPES : NO-ENTRY HABITAT TYPES AND PLANT COMMUNITIES : In Europe and Asia, Scots pine forms a boreal forest type with Norway spruce (Picea abies). Scots pine is listed as a dominant species in the following classification: Forest types and their significance [7].


SPECIES: Pinus sylvestris
WOOD PRODUCTS VALUE : Scots pine is used for pulpwood and sawlogs [42]. IMPORTANCE TO LIVESTOCK AND WILDLIFE : The pine grosbeak feeds on the terminal and lateral buds of Scots pine. Porcupines consume the bark, and girdle small trees. White-tailed deer will browse Scots pine [10]. Moose browse it in Scandinavia and Russia [25,34]. PALATABILITY : When compared to other ornamental species, Scots pine is low in preference for white-tailed deer [10]. NUTRITIONAL VALUE : NO-ENTRY COVER VALUE : NO-ENTRY VALUE FOR REHABILITATION OF DISTURBED SITES : Scots pine is planted for erosion control [42]. It is used to reforest coal mine spoils. Such plantations are valued chiefly for Christmas tree production, providing screening and wildlife food and cover, and aesthetics [5,21,56]. In Europe, it is planted to reforest burned sites [54]. OTHER USES AND VALUES : Scots pine is a highly preferred Christmas tree, accounting for 30 percent of all trees planted for that purpose [42]. As a Christmas tree crop, it can be highly profitable in agroforestry systems which combine the production of row crops with tree plantations [30]. Scots pine is widely planted as an ornamental, and for windbreaks in the central Great Plains [12,38]. Scots pine is used to monitor the effect of air pollution on plants [13]. OTHER MANAGEMENT CONSIDERATIONS : Scots pine is usually managed with a shelterwood or uniform compartment system. In the Northeast and the Great Lakes states, reproduction is abundant on sandy sites [32]. Scots pine requires high light intensities for good growth, but has modest nutritional demands [55]. Certain ground vegetation types are used as site quality indicators for Scots pine in Europe [7,35]. Scots pine performance varies greatly with site and seed source [12,39,42]. Yields for most species in Scots pine stands in Germany were improved when shade-tolerant species (Norway spruce and European beech [Fagus sylvatica]) were grown in the understory. Scots pine yields, however, were slightly decreased under those conditions [2]. Scots pine growth rates decreased with decreasing acidity in greenhouse tests; optimum seedling growth is on acidic soils [8]. Scots pine has more branches per whorl than red pine (Pinus resinosa) or eastern white pine (P. strobus), and is thus weaker at the nodes and subject to wind damage [42]. Scots pine is intermediate in tolerance to foliar sprays of sodium chloride [49]. Insects and Disease: Damaging insect species on Scots pine include pine root collar weevil, pine root tip weevil, European pine sawfly, and others. Scleroderris canker has become a serious problem in Scots pine plantations in many areas. Other diseases include Lophodermum needlecast, brown spot needle disease, and western gall rust [42,43].


SPECIES: Pinus sylvestris
GENERAL BOTANICAL CHARACTERISTICS : Scots pine is an exotic, medium-sized, two-needle pine. Height at maturity usually ranges from 50 to 100 feet (15-30 m) [18,42]. The crown is open and spreading. Needles range from 1.8 to 3.6 inches (4.5-9.0 cm) in length [57]. The bark is relatively thin [18,57]. A taproot is frequently developed on sandy soils, but is not a universal trait for Scots pine. The depth of the taproot ranges from 4.9 to 9.8 feet (1.5-3.0 m), but most of the roots are horizontal and within 7.8 inches (20 cm) of the soil surface [42]. A population of middle-aged Scots pine in Finland had numerous root grafts between neighboring trees in networks of up to ten trees. Water and nutrients are transferred from one tree to another through the grafts (Yli-Vakkuri in [9]). Scots pine is long-lived; individuals of nearly 1,000 years of age occur in northern Sweden [59]. Ages of 200 and 400 years are common in Scandinavia [22]. RAUNKIAER LIFE FORM : Phanerophyte REGENERATION PROCESSES : Scots pine reproduces by seed. Sexual maturity can be reached as early as 5 to 8 years of age; the usual range is from 10 to 15 years of age. Scots pine continues to produce viable seed for up to 200 years. Good seed crops are produced every 3 to 6 years, with light crops in intervening years. Seed cones require alternating wet and dry weather to open; seeds can be retained until early spring. Seed dispersal distances range from 164 to 328 feet (50-100 m) from the parent, though the maximum distance is greater than 0.6 mile (1 km) [42]. Seed quality, germination, and establishment decrease with distance from the parent plant [52]. Scots pine seedling establishment occurs on bare mineral soil. In England, however, where Scots pine is invading heather (Calluna vulgaris)-bracken fern (Pteridium aquilinum) heaths, Scots pine seedlings were found even in dense stands of bracken fern; the limiting factor on these sites appears to be proximity to seed source, rather than density of ground vegetation [33]. Moisture stress, in the form of repeated cycles of wetting and drying, has a pronounced negative effect on Scots pine seed germination [40]. Seedlings establish best with adequate moisture and some shade [42]. Survival is best when seedlings are planted on microsites close to the tops of hills, and lowest in overly moist depressions [19]. There is no naturally occurring vegetative reproduction [42]. SITE CHARACTERISTICS : Scots pine is found from sea level to 8,000 feet (2,440 m) elevation, and grows on a wide variety of soils including peat, though growth on peat usually results in stunted trees [42]. Growth is best on well-drained soils [29]. Soil pH ranges from 4.0 to 7.0, but growth is best between 4.5 and 6.0 [42,56]. Where it is naturalized in northern New York, Scots pine is associated with black cherry (Prunus serotina), red maple (Acer rubrum), sugar maple (A. saccharum), American beech (Fagus grandifolia), quaking aspen (Populus tremuloides), and eastern white pine [42]. SUCCESSIONAL STATUS : Scots pine is intolerant of shade [42]. High mortality rates occur for Scots pine growing under canopy. Few trees survive more than 50 years under suppression; most do not survive even 7 years of shade [44,47]. Scots pine is not very responsive to release from suppression; trees under 20 years old show a modest response [44,47]. Scots pine stands are usually even-aged, or are uneven-aged with distinct age classes. In Scandinavia, 50 to 70 percent of the trees in a stand commonly belong to one age class, with the rest of the trees in the neighboring age classes [22]. Scots pine usually regenerates in gaps (forming even-aged clumps) or after stand-replacing disturbances [44,47,50]. In Sweden, most Scots pine dominated-forests are maintained by fire. In the absence of fire, Scots pine is usually replaced by Norway spruce (Picea abies). On some sites, however, uneven-aged Scots pine stands are self maintaining in the absence of fire. Regeneration peaks on these sites occurred at long intervals and appear to be more related to favorable climatic conditions than to any disturbances. The ability of Scots pine to reproduce without disturbance is attributed to the thin humus and litter layers of these poor sites [44]. The percentage of pine pollen increased after disturbances in soil core samples dated from 1,430 years BP to present, in an area where Scots pine is usually present [4]. SEASONAL DEVELOPMENT : Scots pine pollen cones open from late May to early June. Pollination occurs in early summer and is followed by fertilization 12 months later. Seeds mature and cones ripen from September to October. Seed dispersal occurs from December to March [27,42].


SPECIES: Pinus sylvestris
FIRE ECOLOGY OR ADAPTATIONS : Scots pine forests in Sweden are rated as fire-prone and appear to require repeated fire for their maintenance [15]. In general, pine forests in Europe (particularly Scots pine forests) which were always fire-prone have become even more flammable with the advent of fire exclusion and the discontinuance of the practice of litter collection for use as animal bedding material, fuel, etc. [26]. In Sweden, Scots pine dominates forests that have burned with a mean fire interval of 46 years from approximately 1,100 A.D. to the present. In some areas, the mean fire interval is as short as 30 years, although the impact of fire has been greatly reduced in the last 100 years with fire suppression [59]. A fire return interval ranging from 26 to 146 years was calculated for Scots pine/heather forests in eastern Finland [48]. In the taiga of northern China, the fire cycle for Scots pine forests was estimated at 130 years [50]. The number of years between fires decreased in areas where Scots pine basal area increased in Muddus National Park, Sweden. In this area, Scots pine often predominates at the lower elevations where fire is more common and is replaced by Norway spruce at the higher elevations where fire is less frequent [15]. FIRE REGIMES : Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find Fire Regimes". POSTFIRE REGENERATION STRATEGY : Tree without adventitious-bud root crown Initial-offsite colonizer (off-site, initial community)


SPECIES: Pinus sylvestris
IMMEDIATE FIRE EFFECT ON PLANT : Young Scots pine trees are easily killed by fire due to their thin bark and shallow roots. Based on the ability to recover after defoliation, the fire resistance of 8-year-old Scots pine trees is rated as low [36]. The heat tolerance of 1-year-old Scots pine seedlings is low compared to a number of other conifers, including eastern white pine [24]. Mature trees are better able to withstand fire; old trees in Muddus National Park, Sweden, have numerous fire scars, showing that they have survived repeated fires (intensity unreported). However, severe fire will kill even mature trees [52]. A 1974 surface and crown wildfire in Scotland killed 74 percent of all Scots pine burned. All Scots pine less than 2 inches (5 cm) dbh were killed outright. Trees greater then 15.2 inches (38 cm) in diameter did not have immediate mortality, however [60]. Scots pine seeds are moderately resistant to heat damage, and have a good chance of surviving fire when buried. Seed germination is good even at depths of up to 4.6 inches (10 cm) [52]. Scots pine bark is more resistant to heat than that of Norway spruce, sugar maple, or white ash (Fraxinus americana) [14]. DISCUSSION AND QUALIFICATION OF FIRE EFFECT : NO-ENTRY PLANT RESPONSE TO FIRE : In Sweden, establishment of Scots pine seedlings at high elevations increased after fire [15]. Total pine pollen increased after fires in Swedish core samples dated from 1,430 years BP [4]. A survey of a burned stand of mature Scots pine in northern China showed numerous seedlings, but no saplings [50]. Following the 1974 wildfire in Scotland, Scots pine reproduction was densest on plots with heather. Very few seedlings occurred on sites where sapling stands had been killed by fire. Regeneration was 2,500 seedlings per hectare at postfire year 6. By postfire year 12, some seedlings had overtopped the competing vegetation. Postfire mortality of burned trees was high. By postfire year 6, 45 percent of trees greater than 2.5 inches dbh was died. Much of the postfire mortality was attributed to pine shoot beetle (Myelophilus piniperda) attacks on fire-damaged trees [46,60]. Scots pine may regenerate from seeds released from cones of burned trees [60] as well as from seed from off-site parent trees. Twenty-four years after a wildfire in Sweden, numerous Scots pine seedlings occurred on burned sites, concentrated around surviving trees and near the edges of the burned areas [52]. DISCUSSION AND QUALIFICATION OF PLANT RESPONSE : The climatic conditions that are conducive to fire in Scandinavia are also conducive to the production of large seed crops [52]. FIRE MANAGEMENT CONSIDERATIONS : Fires in Sweden have given rise to uneven-aged stands of Scots pine, particularly in virgin types that have not been disturbed by humans [59]. Fire exclusion in Europe has resulted in a conversion of pine-dominated forests (including Scots pine) to hardwoods [26]. Prescribed burning followed by tilling, followed by natural reforestation (known as swaling), has been practiced in Europe for many years. It has been noted that the more frequently a site has been swaled, the more likely it is that hardwoods will regenerate on the site. Sites that have been burned and tilled only once often result in good Scots pine regeneration [55]. Scots pine does not regenerate on dry sites occupied by Norway spruce due to excessive humus buildup and shading. Such sites can be made more conducive to Scots pine regeneration by prescribed burning. The humus layer is directly reduced by fire. In succeeding years, it continues to decrease in thickness, probably due to decreased root mass. Prescribed burning improves many external growth factors needed for Scots pine establishment, including nutrition, moisture availability, and soil temperature [55]. Prescribed burning has been used in site preparation for the sowing of Scots pine seeds in Norway and Finland [3,48]. Performance of Scots pine approximately 10 years after planting was best on burned sites when compared to performance on sites that were unburned but had slash removed, or sites that were unburned and retained slash [55]. Rhizina undulata root rot has been associated with postfire plantations of Scots pine. As a result, prescribed burning for site preparation has been discontinued in Finland and Sweden [1,54,55]. It is possible that the appearance of Rhizina is associated with prescribed fires that are too low in intensity [55]. However, the rarity of appropriate fire weather for prescribed burning, and the labor-intensive expense of prescribed burning have also contributed to the reduction in prescribed burning in Scandinavia [3].


SPECIES: Pinus sylvestris
REFERENCES : 1. Ahlgren, Isabel F. 1974. The effect of fire on soil organisms. In: Kozlowski, T. T.; Ahlgren, C. E., eds. Fire and ecosystems. New York: Academic Press: 47-72. [18306] 2. Assmann, Ernst. 1970. The principles of forest yield study. Oxford: Pergamon Press. 506 p. [22496] 3. Braathe, Peder. 1974. Prescribed burning in Norway--effects on soil and regeneration. In: Proceedings, annual Tall Timbers fire ecology conference; 1973 March 22-23; Tallahassee, FL. No. 13. Tallahassee, FL: 211-222. [18976] 4. Bradshaw, Richard H. W.: Zackrisson, Olle. 1990. A two thousand year history of a northern Swedish boreal forest stand. Journal of Vegetation Science. 1(4): 519-528. [12762] 5. Brothers, Timothy S. 1988. Indiana surface-mine forests: historical development and composition of a human-created vegetation complex. Southeastern Geographer. 28(1): 19-33. [8787] 6. Brown, James H. 1980. Competition control in Christmas tree plantations. Tree Planters' Notes. Winter: 16-20. [18952] 7. Cajander, A. K. 1949. Forest types and their significance. Acta Forestalia Fennica. 56: 1-105. [22657] 8. Carter, M. R. 1987. Seedling growth and mineral nutrition of Scots pine under acidic to calcareous soil conditions. Soil Science. 144(3): 175-180. [21875] 9. Cooper, Charles F. 1960. Changes in vegetation, structure, and growth of Southwestern pine forests since white settlement. Ecological Monographs. 30(2): 129-164. [3927] 10. Conover, M. R.; Kania, G. S. 1988. Browsing preference of white-tailed deer for different ornamental species. Wildlife Society Bulletin. 16: 175-179. [8933] 11. Craighead, F. C. 1940. Some effects of artificial defoliation on pine and larch. Journal of Forestry. 38: 885-888. [20294] 12. Cunningham, Richard A.; Van Haverbeke, David F. 1991. Twenty-two year results of a Scots pine (Pinus sylvestris L.) provenance test in North Dakota. Res. Pap. RM-298. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station. 9 p. [17114] 13. Czuchajowska, Zuzanna. 1987. Influence of zinc smelter emissions on leaves of Pinus sylvestris and Vaccinium species as revealed by some morphological and ecophysiological indices. Environmental and Experimental Biology. 27(1): 67-83. [9255] 14. Devet, David D. 1940. Heat conductivity of bark in certain selected species. Syracuse, NY: Syracuse University. 83 p. Thesis. [21931] 15. Engelmark, Ola. 1987. Fire history correlations to forest type and topography in northern Sweden. Annales Botanici Fennici. 24(4): 317-324. [6688] 16. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. [905] 17. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [998] 18. Moran, G. F.; Marshall, D. R.; Muller, W. J. 1981. Phenotypic variation and plasticity in the colonizing species Xanthium strumarium L. (Noogoora Burr). Australian Journal of Biological Science. 34: 639-648. [20392] 19. Hagner, Matt. 1989. The influence of microenvironment upon survival and growth in Pinus sylvestris. In: Martinsson, Owe; Packee, Edmond C.; Gasbarro, Anthony; Lawson, Teri, coords. Forest regeneration at northern latitudes close to timber line: Proceedings, 7th annual workshop on silviculture and management of northern forests; 1985 June 16-20; Lulea-Gallivare-Ostersund, Sweden. Gen. Tech. Rep. PNW-GTN-247. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station: 33-38. [17296] 20. Holst, Mark J. 1953. A provenance experiment in Scots pine (Pinus sylvestris). Silvicultural Leaflet No. 96. Chalk River, ON: Department of Northern Affairs and National Resources, Forestry Branch, Division of Forest Research. 4 p. [17715] 21. Hughes, H. Glenn. 1990. Ecological restoration: fact or fantasy on strip-mined lands in western Pennsylvania?. In: Hughes, H. Glenn; Bonnicksen, Thomas M., eds. Restoration '89: the new management challenge: Proceedings, 1st annual meeting of the Society for Ecological Restoration; 1989 January 16-20; Oakland, CA. Madison, WI: The University of Wisconsin Arboretum, Society for Ecological Restoration: 237-243. [14699] 22. Jones, E. W. 1945. The structure and reproduction of the virgin forest of the north temperate zone. New Phytologist. 44: 130-148. [10229] 23. Kartesz, John T.; Kartesz, Rosemarie. 1980. A synonymized checklist of the vascular flora of the United States, Canada, and Greenland. Volume II: The biota of North America. Chapel Hill, NC: The University of North Carolina Press; in confederation with Anne H. Lindsey and C. Richie Bell, North Carolina Botanical Garden. 500 p. [6954] 24. Kayll, A. J. 1968. Heat tolerance of tree seedlings. In: Proceedings, annual Tall Timbers fire ecology conference; 1968 March 14-15; Tallahassee, FL. No. 8. Tallahassee, FL: Tall Timbers Research Station: 89-105. [17849] 25. Danell, Kjell; Niemela, Pekka; Varvikko, Tuomo; Vuorisalo, Timo. 1991. Moose browsing on Scots pine along a gradient of plant productivity. Ecology. 72(5): 1624-1633. [26103] 26. Komarek, E. V. 1983. Fire as an anthropogenic factor in vegetation ecology. In: Holzner, W.; Werger, M. J. A.; Ikusima, I., eds. Man's impact on vegetation. Boston, MA: Dr W. Junk Publishers: 77-82. [15273] 27. Krugman, Stanley L.; Jenkinson, James L. 1974. Pinaceae--pine family. In: Schopmeyer, C. S., technical coordinator. Seeds of woody plants in the United States. Agric. Handb. 450. Washington, DC: U.S. Department of Agriculture, Forest Service: 598-637. [1380] 28. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. [1384] 29. Kudish, Michael. 1992. Adirondack upland flora: an ecological perspective. Saranac, NY: The Chauncy Press. 320 p. [19376] 30. Kurtz, W. B.; Thurman, S. E.; Monson, M. J.; Garrett, H. E. 1991. The use of agroforestry to control erosion--financial aspects. Forestry Chronicle. 67(3): 254-257. [21865] 31. Leaf, Albert L. 1956. Growth of forest plantations on different soils of Finland. Forest Science. 2(2): 121-126. [20125] 32. Little, Elbert L., Jr. 1979. Checklist of United States trees (native and naturalized). Agric. Handb. 541. Washington, DC: U.S. Department of Agriculture, Forest Service. 375 p. [2952] 33. Marrs, R. H.; Hicks, M. J. 1986. Study of vegetation change at Lakenheath Warren: a re-examination of A. S. Watt's theories of bracken dynamics in relation to succession and vegetation management. Journal of Applied Ecology. 23: 1029-1046. [9969] 34. Niemela, P.; Danell, K. 1988. Comparison of moose browsing on Scots pine (Pinus sylvestris) and lodgepole pine (P. contorta). Journal of Applied Ecology. 25: 761-775. [7915] 35. Nieppola, Jari. 1992. Long-term vegetation changes in stands of Pinus sylvestris in southern Finland. Journal of Vegetation Science. 3: 475-484. [21845] 36. Pryor, L. D. 1940. The effect of fire on exotic conifers: Some notes on the effect of fire on exotic conifers in the Australian capital territory. Australian Forestry. 5: 37-38. [11391] 37. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. [2843] 38. Read, Ralph A. 1964. Tree windbreaks for the Central Great Plains. Agric. Handb. 250. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. [2897] 39. Ruby, J. L.; Wright, J. W. 1976. A revised classification of geographic varieties in Scots pine. Silvae Genetica. 25: 5-6. [21872] 40. Russo, Vincent M. 1978. Development of Pinus seedlings grown from seed subjected to drying and wetting cycles. Forest Science. 24(4): 537-541. [21868] 41. Saari, Eino. 1923. Forest fires in Finland: with special reference to the state forests. Acta For. Fenn. 26: 143-155. [22495] 42. Skilling, Darroll D. 1990. Pinus sylvestris L. Scots pine. In: Burns, Russell M.; Honkala, Barbara H., technical coordinators. Silvics of North America. Volume 1. Conifers. Agric. Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest Service: 489-496. [13409] 43. Skilling, Darroll D.; Nicholls, Thomas H. 1974. Brown spot needle disease-biology and control in Scots pine plantations. Research Paper NC-109. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest Experiment Station. 19 p. [10512] 44. Steijlen, Ingeborg; Zackrisson, Olle. 1987. Long-term regeneration dynamics and successional trends in a northern Swedish coniferous forest. Canadian Journal of Botany. 65: 839-848. [16463] 45. Stickney, Peter F. 1989. Seral origin of species originating in northern Rocky Mountain forests. Unpublished draft on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT; RWU 4403 files. 7 p. [20090] 46. Sykes, J. M. 1987. Further observations on the recovery of vegetation in the Caledonian pinewood of Coille Creag-loch after fire. Transactions of the Botanical Society of Edinburgh. 45(2): 161-162. [6687] 47. Tarasiuk, S.; Zwieniecki, M. 1990. Social-structure dynamics in uneven-aged Scots pine (Pinus sylvestris) regen. under canopy at the Kaliszki Preserve, Kampinoski Natl. Park. Forest Ecology and Management. 35: 277-289. [21874] 48. Tolonen, Kimmo. 1983. The post-glacial fire record. In: Wein, Ross W.; MacLean, David A., eds. The role of fire in northern circumpolar ecosystems. Scope 18. New York: John Wiley & Sons: 21-44. [18503] 49. Townsend, A. M. 1989. The search for salt tolerant trees. Arboricultural Journal. 13(1): 67-73. [13061] 50. Uemura, Shigeru; Tsuda, Satoshi; Hasegawa, Sakae. 1990. Effects of fire on the vegetation of Siberian taiga predominated by Larix dahurica. Canadian Journal of Forestry Research. 20: 547-553. [11808] 51. U.S. Department of Agriculture, Soil Conservation Service. 1982. National list of scientific plant names. Vol. 1. List of plant names. SCS-TP-159. Washington, DC. 416 p. [11573] 52. Uggla, Evald. 1959. Ecological effects of fire on north Swedish forests. [Place of publication unknown]: Almqvist and Wiksells. 18 p. [9911] 53. Uggla, Evald. 1974. Fire ecology in Swedish forests. In: Proceedings, annual Tall Timbers fire ecology conference; 1973 March 22-23; Tallahassee, FL. No. 13. Tallahassee, FL: 171-190. [18974] 54. Viro, P. J. 1969. Prescribed burning in forestry. Metsan tutkimuslaitoksen Julkaisuja. 67: 1-49. [22493] 55. Viro, P. J. 1974. Effects of forest fire on soil. In: Kozlowski, T. T.; Ahlgren, C. E., eds. Fire and ecosystems. New York: Academic Press: 7-45. [18305] 56. Vogel, Willis G. 1981. A guide for revegetating coal minespoils in the eastern United States. Gen. Tech. Rep. NE-68. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station. 190 p. [15577] 57. Welsh, Stanley L.; Atwood, N. Duane; Goodrich, Sherel; Higgins, Larry C., eds. 1987. A Utah flora. Great Basin Naturalist Memoir No. 9. Provo, UT: Brigham Young University. 894 p. [2944] 58. Wright, T. W.; Will, G. M. 1958. The nutrient content of Scots and Corsican pines growing on sand dunes. Forestry. 31: 13-25. [18334] 59. Zackrisson, Olle. 1980. Forest fire history: ecological significance and dating problems in the north Swedish boreal forest. In: Stokes, Marvin A.; Dieterich, John H., technical coordinators. Proceedings of the fire history workshop; 1980 October 20-24; Tucson, AZ. Gen. Tech. Rep. RM-81. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain Forest and Range Experiment Station: 120-125. [16052] 60. Sykes, J. M.; Horrill, A. D. 1981. Recovery of vegetation in a Caledonian pinewood after fire. Transactions of the Botanical Society of Edinburg. 43: 317-325. [22006]