Pinus strobus, eastern white pine
Carey, Jennifer H. 1993. Pinus strobus, eastern white pine. In: Fire Effects Information System, [Online]. U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station, Fire Sciences Laboratory (Producer). Available: https://research.fs.usda.gov/feis/species-reviews/pinstr
| Abbreviation | Common Name | Scientific Name | Classification | Status |
|---|---|---|---|---|
| Plants | ||||
| PINSTR | eastern white pine | Pinus strobus | Life Form: Plants/Tree Kingdom: Plantae Class: Conifer Order: Pinales Family: Pinaceae Genus: Pinus | Fed. Protected: No Nativity: Native Invasiveness: Noninvasive |
Taxonomy
The currently accepted scientific name of eastern white pine is Pinus strobus L. [31]. Little [31] recognizes two varieties: the typical variety and Chiapas white pine (Pinus strobus var. chiapensis Mart.). Chiapas white pine, native to the mountains of southern Mexico and Guatemala, is also recognized as a separate species, Pinus chiapensis (Mart.) Andresen [43]. This review discusses the typical variety, eastern white pine.
Synonyms
- Strobus strobus (L.) Small
Other Common Names
northern white pine, white pine, northern pine, soft pine, Weymouth pine, pin blanc
General Distribution
Eastern white pine is distributed from Newfoundland west to extreme southeastern Manitoba and south to the Great Lake States, along the Atlantic seaboard to New Jersey, and in the Appalachian Mountains to northern Georgia. It also occurs in Iowa, western Kentucky, western Tennessee, and Delaware [31,68].
States and Provinces
- United States: CT DE GA IL IN IA KY ME MD MA MI MN NH NJ NY NC OH PA RI SC TN VT VA WV WI
- Canada: MB NB NF ON PE PQ
Site Characteristics
Eastern white pine in the Adirondack Mountains, Warren County, New York. (CC BY-SA 4.0)
Eastern white pine occurs on a variety of sites along the full moisture gradient from wet bogs and moist streambottoms to xeric sand plains and rocky ridges [7,67]. In Maine and New Brunswick, eastern white pine occurs in well-drained, raised bogs [8]; in Michigan, it occurs on sand dunes [42]. In the southern Appalachian Mountains and in Pennsylvania, pure stands mainly occur on northerly aspects, in coves, and on streambottoms [11]. Eastern white pine is common on the east shore of lakes where blowdowns create openings for regeneration [28].
In New England, eastern white pine usually occurs between sea level and 2,000 feet (610 m) in elevation; on Catamount Mountain in the Adirondack Mountains of New York, it occurs up to 3,168 feet (966 m). In the southern Appalachian Mountains, it occurs between 1,200 and 3,500 feet (370-1,070 m) [11,28]
Eastern white pine grows on nearly all soil types within its range. It is most competitive on fairly infertile sandy soils, such as well-drained outwash soils. On clay or poorly drained soils, eastern white pine occurs only as individuals or in small groups. It grows on fine sandy loams and silty loams on disturbed sites if there is little hardwood competition [68].
Eastern white pine is the characteristic old-field species in New England. Nearly pure stands develop on old fields where seed is ample and sod is intact [53]. In the Hudson River valley, eastern white pine dominates the finer textured, less rocky old-field sites, whereas oak communities dominated the coarser textured, rockier sites [15].
Plant Communities
Eastern white pine frequently dominates or codominates xeric northern pine forests [7,40]. In mixed hardwood forests, it often occurs as a scattered dominant tree towering above the surrounding hardwoods [19,40].
Publications listing eastern white pine as dominant or codominant are as follows:
- A multivariate analysis of forest communities in the western Great Smoky Mountains National Park [3]
- The vegetation of Wisconsin [7]
- The principal plant associations of the Saint Lawrence Valley [9]
- Field guide: forest habitat types of northern Wisconsin [25]
- Plant communities of Voyageurs National Park, Minnesota, U.S.A. [29]
- A classification of the deciduous forest of eastern North America [37]
- Virgin plant communities of the Boundary Waters Canoe Area [41]
- Forest associations in the Harvard Forest [53]
- Plant community pattern analysis: a cartographic approach applied in the Lac des Deux-Montagnes area (Quebec) [62]
Tree associates of eastern white pine not mentioned in Table A1 include sweet birch (Betula lenta), bigtooth aspen (Populus grandidentata), quaking aspen (P. tremuloides), black cherry (Prunus serotina), and black oak (Quercus velutina) [11].
Understory species are scarce in pure stands of eastern white pine. On dry sites, associates include blueberries (Vaccinium spp.), wintergreen (Gaultheria procumbens), dwarf bush-honeysuckle (Diervilla lonicera), sweetfern (Comptonia peregrina), bracken fern (Pteridium aquilinum), clubmosses (Lycopodium spp,), and broomsedge (Andropogon virginicus). On moist, rich sites associates include wood sorrel (Oxalis spp.), partridgeberry (Mitchella repens), wild sarsaparilla (Aralia nudicaulis), jack-in-the-pulpit (Arisaema triphyllum), and hay-scented fern (Dennstaedtia punctilobula). Other associates include bigleaf aster (Aster macrophyllus), Canada mayflower (Maianthemum canadense), and bunchberry (Cornus canadensis) [11,41,25].
Botanical Description
Eastern white pine is a large, native, evergreen conifer. It grows rapidly and in 40 years can be 60 feet (18.3 m) tall and 8 to 10 inches (20-25 cm) in d.b.h. [7]. Individuals of 150 feet (46 m) and 40 inches (102 cm) in d.b.h. were common in virgin forests. Eastern white pine commonly reaches 200 years of age and may exceed 450 years [68]. In closed stands, boles are free of branches for over two-thirds of their length. Needles are 2.5 to 5.0 inches (6-13 cm) long, and the winged seeds are about 0.8 inches (2 cm) long. The roots are wide spreading and moderately deep without a distinct taproot [20].
Raunkiaer Life Form (Raunkiaer 1934)
- Phanerophyte
Seasonal Development
Eastern white pine male strobili open and shed pollen in April through June, depending on latitude. Fertilization occurs 13 months after pollination. Cones ripen and seeds are dispersed August through September, about 2 years after cone initiation [7,26]. Seeds germinate in the spring [7]. Terminal shoot growth is usually completed by the end of June [68].
Regeneration Processes
Eastern white pine with mature cones, Quebec, Canada. (CC BY-NC 4.0)
Eastern white pine begins producing cones when 5 to 10 years old, but good seed production does not occur until trees are at least 20 to 30 years old [26]. Good seed years occur every 3 to 5 years, with some seed produced in intervening years [7].
Seeds are dispersed primarily by wind. Seeds travel 200 feet (60 m) within a stand and more than 700 feet (210 m) in the open. Animals also disperse seeds. Gray squirrel seed caches were responsible for white pine reproduction under red oak (Quercus rubra) stands in southern New Hampshire [68]. White-footed mice and red-backed voles bury caches containing 20 to 30 eastern white pine seeds beneath the litter but on top of the mineral soil. Caches that escape revisitation and decimation produce seedlings [1].
Favorable seedbeds include moist mineral soil, mosses (Polytrichum spp.), and short grass cover of light to medium density. Dry mineral soil, pine litter, lichen, and very thin or very thick grass covers are poor seedbeds in full light but adequate in shade [68]. Eastern white pine shows very limited delayed emergence the second year after seed fall, and none after 3 years [57].
Eastern white pine colonizes disturbed sites, but a nurse crop of aspen (Populus spp.), birch (Betula spp.), or other pioneer species promotes best regeneration [7]. When colonizing old fields, eastern white pine is more likely to become established in openings than under herbs. Even though seedling emergence and survivorship are higher under herbs, so too is seed and seedling predation by rodents [14].
Eastern white pine seedlings require at least 20 percent of full light for survival. They achieve maximum height growth in 45 percent of full light [51]. Early growth is slow, but between 10 and 20 years of age, the average annual height growth is about 16 inches (40 cm) per year [68].
Eastern white pine does not reproduce vegetatively [68].
Successional Status
Eastern white pine is intermediate in shade tolerance [2] and is present in all successional stages. It is a pioneer species on old fields and other disturbed sites, a long-lived successional species, and a physiographic climax species on dry, sandy soils [53,68]. Eastern white pine is sometimes a component of climax forests on certain sites such as steep slopes and ridge tops where windfall provides regeneration opportunities [54].
Eastern white pine forests frequently establish after disturbance and are even-aged. However, uneven-aged forests also occur. Eastern white pine has dominated an uneven-aged old-growth forest in southern Ontario for at least 700 years. In this forest, canopy gaps created by the death of individual trees from surface fire or windthrow enable eastern white pine to regenerate [44].
Eastern white pine succeeds aspen post-disturbance forests. The diffuse aspen canopy allows enough light for eastern white pine to regenerate [52]. Bigtooth aspen colonized and was the early dominant on a burn in northern Michigan, but 53 years after the fire, eastern white pine and red maple (Acer rubrum) were dominant [49].
More shade-tolerant species succeed eastern white pine. In the Boundary Waters Canoe Area in Minnesota, it begins to be replaced by white spruce (Picea glauca), eastern white-cedar (Thuja occidentalis), balsam fir (Abies balsamea), and paper birch (Betula papyrifera) about 360 years after fire [16].
Immediate Fire Effects
Once eastern white pine reaches 60 feet (18 m) in height and develops rough bark on the lower bole, it tolerates low-severity fire [32,69]. Large individuals usually survive moderate-severity fires [69]. Fires of more than moderate severity during the first 50 years may destroy the entire stand [60].
Total scorching of foliage typically kills eastern white pine [32], but scorching less than 50 percent is usually not lethal [35,61,66]. Two stands, in which 96 percent of the eastern white and red pines were 9 inches (23 cm) in diameter or larger, were prescribed burned in late spring (May 31 and June 15). The percent crown scorch was estimated after the fire and 1-year mortality was assessed. There was no mortality in trees with less than 46 percent crown scorch. Mortality was 50 percent in the 81 to 85 percent crown scorch class and 100 percent in trees with more than 96 percent crown scorch [35].
Many eastern white pine were crown scorched up to 50 percent in a March prescribed fire ranging in intensity from 30 to 250 btu/s/ft (100-850 kW/m), but all buds emerged later in the spring [66].
A laboratory study in August in which eastern white pine seedlings were exposed to different temperature regimes for 4 minutes, demonstrated even less mortality with high percentages of needle scorch. The seedlings withstood up to 90 percent needle scorch with only 10 to 20 percent mortality. The author suggests that there may be two lethal temperatures, one that kills needles and one that kills terminal buds. Therefore percent needle scorch may not be directly related to mortality in eastern white pine [35].
Deep-burning ground fires may cause root injuries that are more serious than crown injury. Where 75 percent or more of the major surface roots had been killed or severely damaged by fire, but only a third or less of the crown was scorched, mortality 3 years after the fire was 100, 60, and 40 percent for small trees (2 to 6 inches [5-15 cm] in diameter), medium trees (7 to 11 inches [16-29 cm]), and large trees (greater than 12 inches [30 cm]), respectively. For trees with less than 25 percent root kill or injury and more than two-thirds of the crown scorched, mortality for small, medium, and large trees was only 80, 46, and 14 percent, respectively [32].
Heated air at 144 degrees Fahrenheit (62 deg C) applied for 1 minute killed 50 percent of 5-year-old eastern white pine seedlings that averaged 16 inches (40 cm) in height, 0.2 inch (0.5 cm) butt diameter, and less than 0.04 inch (0.1 cm) in bark thickness [24].
Postfire Regeneration Strategy (Stickney 1989)
- Tree without adventitious-bud root crown
- Initial-offsite colonizer (off-site, initial community)
- Secondary colonizer - on-site seed
- Secondary colonizer - off-site seed
Fire Adaptations
Eastern white pine is moderately fire resistant. Mature trees survive most surface fires because they have thick bark, branch-free boles, and a moderately deep rooting habit. Younger trees are not as fire resistant [68]. The needles have relatively low resin content so are not highly flammable [30].
The typical fuel type under eastern white and red pine stands is an organic layer 2 to 4 inches (5-10 cm) deep, a continuous needle layer, a moderate forb and shrub layer, and a moderately dense understory. Ground fires spread slowly in this fuel type. Dry, windy conditions are required for fires to crown and have a high rate of spread [23].
Plant Response to Fire
Eastern white pine colonizes burns if a seed source is nearby [5,18,32,33].
A thick organic layer is an unfavorable seedbed because roots of new seedlings desiccate before reaching mineral soil. The higher the fire severity, the more organic material is removed. However, severe fire also consumes seeds and rhizomes and thus reduces the early postfire herbaceous cover which serves to shelter young seedlings from heat. Initially, as the amount of postfire shelter is reduced by increasing fire severity, eastern white pine survival decreases. Eventually, however, the reduction in organic matter depth is sufficient to compensate for the lack of shelter and the survival of eastern white pine increases. Establishment is highest when mineral soil is exposed [56].
Fire wounds provide entry to fungi which cause heart rot in eastern white pine [32].
The following Research Project Summaries provide information on prescribed fire use and postfire response of plant community species, including eastern white pine, that was not available when this species review was originally written:
- Prescribed burning experiments in red and eastern white pine forests of eastern Ontario
- Effects of surface fires in a mixed red and eastern white pine stand in Michigan
- Early postfire response of southern Appalachian Table Mountain-pitch pine stands to prescribed fires in North Carolina and Virginia
Fire Regimes
Forests dominated or codominated by eastern white pine have different fire regimes depending on site and associated species. The natural fire regime in eastern white pine-red pine forests consists of nonlethal surface fires at 5- to 50-year intervals punctuated by severe stand-replacing fires at longer intervals. In the Boundary Waters Canoe Area in Minnesota, low-severity fire intervals averaged 36 years, and severe fire intervals averaged 160 years. Eastern white pine forests growing on more mesic sites with a substantial shade-tolerant component probably undergo only one fire every 150 to 350 years [16,17]. Some large individuals survive or escape severe fires and serve as seed sources for a new stand. Severe fire creates large open areas with ash or mineral seedbeds and reduces competition, good conditions for eastern white pine regeneration [19,65].
For additional fire regime information, search FEIS for this species by entering the species name on the Advanced Search page and selecting “Fire Regime” as the publication type.
Fire Management Considerations
Prescribed fire is used for eastern white pine seedbed preparation. Two fires conducted in consecutive years are recommended before the first partial cut of a shelterwood system. A fire conducted after the partial cut may be too hot because of slash and may cause mortality of the remaining trees. The first fire should be in the spring before the understory leaves emerge so that the fire is hot enough to remove most of the soil surface organic material. A second fire after the leaves emerge the following year helps reduce competition. A suggested reasonable fire intensity for preparing a seedbed and controlling competition is 116 to 173 btu/s/ft (400-600 kW/m). Extreme care must be taken if prescribed burning stands younger than 80 years old [61].
Two consecutive annual fires in a 90-year-old eastern white and red pine stand in Ontario improved the conditions necessary for pine regeneration. The fires were low in intensity (22 to 23 btu/s/ft [78-79 kW/m]) and did not harm the overstory. The litter layer was consumed, and the understory changed from one dominated by balsam fir saplings to one dominated by herbaceous species. However, very little eastern white pine reproduction occurred in the first 3 postfire years [36].
The white pine cone beetle larvae spend 9 to 10 months a year in dead cones on the forest floor. The beetle can be controlled by a low-severity surface fire in early spring before it emerges [66].
Federal Status
None
Other Status
No entry.
Importance to Wildlife and Livestock
Eastern white pine provides food and habitat for numerous wildlife species. Songbirds and small mammals eat eastern white pine seeds. Snowshoe hares, white-tailed deer, and cottontails browse the foliage; the bark is eaten by various mammals [68]. Pocket gophers graze the roots of seedlings and young trees [21].
Northeastern pine forests can support a rich community of breeding birds [4]. Bald eagles build nests in living eastern white pine, usually at a main branch located below the crown top [34]. Eastern white pine, especially those with broken tops, provide valuable habitat for cavity-nesting wildlife [10].
Young black bear cubs use large eastern white pine to climb to safety. In northeastern Minnesota, black bear mothers and cubs spent more than 95 percent of the time in April and May within 600 feet (180 m) of either an eastern white pine or an eastern hemlock larger than 20 inches (50 cm) in d.b.h. [48].
Palatability and Nutritional Value
Eastern white pine browse is of intermediate preference to white-tailed deer [12]. Although available, it was not browsed by moose in Ontario [6].
Cover Value
No entry.
Value for Rehabilitation or Restoration of Disturbed Sites
Eastern white pine is used extensively for stabilizing strip-mine spoils, especially in northern Appalachian coal fields. Eastern white pine has a lower soil pH limit of 4.0. Seedlings tolerate limited shade from herbaceous ground cover better than other pine species [58,64]. Eastern white pine growth is adversely affected by high levels of soluble salts and by the depth of the mine soil. These effects can be avoided by selecting nonpyritic sandstone material for surface placement and by minimizing soil compaction [58].
Eastern white pine planted on bituminous coal mine spoils in Pennsylvania averaged 6.1 inches (15.5 cm) d.b.h. and 27 feet (8.2 m) in height after 30 years [63].
Other Uses
Eastern white pine is a valuable timber species in the eastern United States and Canada. The soft wood is of medium strength, easily worked, and stains and finishes well. It is used for doors, moldings, trim, siding, paneling, cabinet work, and furniture [20,68].
Other Management Considerations
The frequency of eastern white pine is lower in today's forests than in presettlement forests. Eastern white pine was heavily logged in the 1800's in the north-central United States. Regeneration after the early logging was poor because of the lack of seed trees and the destruction of remaining seedlings and saplings by fire [39,41]. In the northeastern United States, eastern white pine temporarily increased in abundance through colonization of abandoned fields and pastures. Many of these stands reached commercial maturity by the early 1900's and were harvested. Hardwoods, which had invaded the understory, now dominate many of these old-field sites [46].
The two-cut shelterwood method is recommended for maximizing regeneration of eastern white pine. The first cut removes 40 to 60 percent of the overstory, and the final cut occurs 5 to 10 years later after seedlings are well established. Established individuals respond well to release [67].
Two of the more damaging pests of eastern white pine are the white pine weevil (Pissodes strobi) and white pine blister rust (Cronartium ribicola) [67,68]. Eastern white pine is infrequently planted in the north-central region because of the inevitable damage caused by the rust [40]. See Fire Management slot for control of the white pine cone beetle (Conophthorus coniperda), which is often responsible for complete crop failure.
The growth rate of all pine species in the New Jersey Pine Barrens except eastern white pine has decreased since the 1950's; this decrease in growth rate may be the caused by acid rain [22]. Eastern white pine germination and emergence are not greatly affected by soil acidity caused by acid rain [47,50].
Table A1— Forest and range ecosystems, Bureau of Land Management (BLM) physiographic regions, Kuchler plant associations, Society for American Foresters (SAF) forest cover types, and Society for Rangeland Management (SRM) rangeland cover types in which this species occurs.
Forest and Range Ecosystems (Garrison et al. 1977)
- FRES10 White - red - jack pine
- FRES11 Spruce - fir
- FRES13 Loblolly - shortleaf pine
- FRES15 Oak - hickory
- FRES17 Elm - ash - cottonwood
- FRES18 Maple - beech - birch
- FRES19 Aspen - birch
BLM Physiographic Regions (Bernard and Brown 1977)
- No entry.
Kuchler Plant Associations (Kuchler 1964)
- K093 Great Lakes spruce - fir forest
- K095 Great Lakes pine forest
- K096 Northeastern spruce - fir forest
- K097 Southeastern spruce - fir forest
- K099 Maple - basswood forest
- K100 Oak - hickory forest
- K101 Elm - ash forest
- K102 Beech - maple forest
- K104 Appalachian oak forest
- K106 Northern hardwoods
- K107 Northern hardwoods - fir forest
- K108 Northern hardwoods - spruce forest
- K110 Northeastern oak - pine forest
- K111 Oak - hickory - pine forest
SAF Cover Types (Eyre 1980)
- 1 Jack pine
- 5 Balsam fir
- 14 Northern pin oak
- 15 Red pine
- 18 Paper birch
- 19 Gray birch - red maple
- 20 White pine - northern red oak - red maple
- 21 Eastern white pine
- 22 White pine - hemlock
- 23 Eastern hemlock
- 24 Hemlock - yellow birch
- 25 Sugar maple - beech - yellow birch
- 26 Sugar maple - basswood
- 27 Sugar maple
- 30 Red spruce - yellow birch
- 31 Red spruce - sugar maple - beech
- 32 Red spruce
- 33 Red spruce - balsam fir
- 35 Paper birch - red spruce - balsam fir
- 37 Northern white-cedar
- 39 Black ash - American elm - red maple
- 43 Bear oak
- 44 Chestnut oak
- 45 Pitch pine
- 51 White pine - chestnut oak
- 53 White oak
- 57 Yellow-poplar
- 59 Yellow-poplar - white oak - northern red oak
- 60 Beech - sugar maple
- 108 Red maple
SRM Rangeland Cover Types (Shiflet 1994)
- No entry.
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