Jack Pine

Pinus banksiana reaches its largest size and best form in Canada. In western Alberta and in northeastern British Columbia, it is sympatric with P . contorta and forms hybrid swarms with that species.

Jack pine ( Pinus banksiana ) is the territorial tree of the Northwest Territories.

Trees to 25 m tall; trunk straight or crooked, to 0.6 m d.b.h. in native range; bark orange- or red-brown, scaly; crown irregularly rounded or flat topped; branchlets orange-red or red-brown, aging gray-brown, slender, rough; winter buds red-brown, ovoid, resinous. Needles 2 per bundle, yellow-green, twisted, 2-5 cm × 1-1.5(-2) mm, stomatal lines present on all surfaces, fine, base with semipersistent sheath 3-6 mm, margin finely serrulate. Seed cones upcurved, nearly sessile or shortly pedunculate, tan to pale brown or greenish yellow, ovoid when open, asymmetric, 3-5.5 cm, maturing in 2 years, then soon shedding seeds or often long serotinous and shedding seeds only with age or after fire. Apophyses mostly depressed but increasingly mamillate toward outer part, basal of cone; umbo depressed, sunken centrally, small, unarmed or with a small, reflexed apicula. Seeds brown or nearly black, compressed obovoid, oblique, 4-5 mm; wing 1-1.2 cm.

Trees to 27m; trunk to 0.6m diam., straight to crooked; crown becoming irregularly rounded or spreading and flattened. Bark orange- to red-brown, scaly. Branches descending to spreading-ascending, poorly self-pruning; twigs slender, orange-red to red-brown, aging gray-brown, rough. Buds ovoid, red-brown, 0.5--1cm, resinous; scale margins nearly entire. Leaves 2 per fascicle, spreading or ascending, persisting 2--3 years, 2--5cm ´ 1--1.5(--2)mm, twisted, yellow-green, all surfaces with fine stomatal lines, margins finely serrulate, apex acute to short-subulate; sheath 0.3--0.6cm, semipersistent. Pollen cones cylindric, 10--15mm, yellow to orange-brown. Seed cones maturing in 2 years, shedding seeds soon thereafter or often long-serotinous and shedding seeds only through age or fire, upcurved, asymmetric, lanceoloid before opening, ovoid when open, 3--5.5cm, tan to light brown or greenish yellow, slick, nearly sessile or short-stalked, most apophyses depressed but increasingly mammillate toward outer cone base; umbo central, depressed, small, sunken centrally, unarmed or with a small, reflexed apiculus. Seeds compressed-obovoid, oblique; body 4--5mm, brown to near black; wing 10--12mm. 2 n =24.

Cultivated. Beijing Shi, Heilongjiang (Harbin Shi), Henan (Jigong Shan), Jiangsu (Nanjing Shi), Jiangxi (Lu Shan), Liaoning, Shandong [native to N North America]

Fire successional in boreal forests, tundra transition, dry flats, and hills, sandy soils; 0--800m; Alta., B.C., Man., N.B., N.W.T., N.S., Ont., P.E.I., Que., Sask.; Ill., Ind., Maine, Mich., Minn., N.H., N.Y., Pa., Vt., Wis.

Pinus divaricata (Aiton) Sudworth; P. sylvestris Linnaeus [var.] d divaricata Aiton

jack pine
scrub pine
northern scrub pine
gray pine
black pine
Banksian pine
Hudson Bay pine
Banks pine
princess pine

More info for the term: cover

Jack pine stands provide cover to mammals such as moose [8] and snowshoe
hares [12].  Debris and seedlings in burned stands provide cover for
smaller mammals such as red-backed voles [44].

More info for the terms: serotinous, tree

Jack pine is a small to medium-sized, native, coniferous, evergreen tree
with 0.75- to 2.0-inch-long (2-5 cm) needles.  Mature jack pine are
usually 55 to 65 feet (17-20 m) tall and 8 to 10 inches (20-25 cm) in
d.b.h. but can attain a maximum height of 100 feet (30 m) and a diameter
of 25 inches (64 cm) [67].  On extremely harsh, sandy sites, jack pine
is small and bushy [31].  Although the canopy begins showing signs of
decay by age 75, jack pine can live more than 200 years [17].  A
243-year-old jack pine was found in the Boundary Waters Canoe Area in
Minnesota [40].

Jack pine develops a taproot as a seedling and maintains it to maturity.
On deep, well-drained soils, roots of mature trees may penetrate 9 feet
(2.7 m).  The abundant lateral roots are mostly confined to the upper 18
inches (46 cm) of soil [67].

Although the species is predominantly closed-coned, individual trees can
have nonserotinous cones or a combination of serotinous and
nonserotinous cones.  Mature stands with mostly open-coned trees are
common in the southern Great Lakes region and sporadic in the East [29].

Jack pine occurs in Canada and in the north-central and northeastern
United States.  The northern boundary of its range extends east from the
Mackenzie River in the Northwest Territories to Cape Breton Island, Nova
Scotia.  Its range extends southwest from Nova Scotia to Maine, New
Hampshire, Vermont, northern New York, Michigan, extreme northwestern
Indiana, and northeastern Illinois, and northwest through Wisconsin and
Minnesota to Manitoba, Saskatchewan, central Alberta, and extreme
northeastern British Colombia [48].  Jack pine has been planted outside
its native range in the Central States and in Alaska.

More info for the terms: cone, duff, fire intensity, fire regime, forest, fuel, fuel continuity, high-severity fire, lichen, litter, natural, seed, serotinous

Of all boreal forest conifers, jack pine is best adapted to fire [66].
With medium thick bark [15], mature individuals have only a moderate
tolerance of fire, but populations survive because of delayed seed
release from serotinous cones, early reproductive maturity, fast growth
rates in full sun, and preference for mineral soil seedbeds [54,66].

In a model that integrates plant population dynamics and disturbance,
jack pine is used to illustrate a species that maximizes the probability
of being reproductively mature at the time of the next recruitment
opportunity.  Fire provides the regeneration opportunity which usually
results in mortality of the mature forest [27].

Cone serotiny:  The resin of serotinous cones melts when heated, usually
at temperatures in excess of 140 degrees Fahrenheit (60 deg C).  In one
study, cones opened in 80 seconds at 200 degrees Fahrenheit (93 deg C)
and within 20 seconds at temperatures above 400 degrees Fahrenheit (204
deg C).  Seed viability is not markedly affected by heating, unless the
cone ignites, which results in complete loss of seed viability.  For
cones at 8 percent moisture content, the interval between cone opening
and cone ignition lies between about 200 and 1,300 degrees Fahrenheit
(93-705 deg C), depending on the time of exposure.  Cones exposed to
temperatures of 800 degrees (427 deg C) or less did not ignite during a
5-minute test.  Cones ignited in 60 seconds when exposed to temperatures
of 900 degrees (482 deg C) Fahrenheit and in 2 seconds when exposed to
temperatures of 1,300 degrees Fahrenheit (705 deg C).  Heating cones at
900 degrees Fahrenheit (482 deg C) for 30 seconds had no adverse effect
on germination.  Jack pine seeds unprotected by cones remain viable when
exposed to high temperatures until the wings ash and the seed coats
crack [9].  Crown torching does not ignite cones because the high
temperatures are unlikely to last more than 3 minutes [9].

Regeneration:  Seeds are dispersed from cones after fire and germinate
on burned duff or mineral soil exposed by fire.  Regeneration failures
are associated with low-severity surface fires that result in little
crown involvement [76] or in little duff removal [11].   

Fire regime:  Estimates of fire intervals in jack pine forests are
generally less than 50 years [40].  Based on jack pine fire scars, the
shortest and longest times between major fires in jack pine forests of
northern Ontario were 5 and 30 years, respectively [50].  The mean fire
return interval for jack pine forests in the Athabasca Plains in
northern Saskatchewan and northeastern Alberta is 38 years [16].  Large
upland ridges and ridge complexes, far from natural fire breaks, burn
most frequently.  Jack pine forests that burn more frequently than every
5 to 10 years become pine barrens [31].  Major stand-replacing fires in
the Boundary Waters Canoe Area occurred in years with summer droughts
[40].

The accumulation of litter and debris on the forest floor over time
increase the likelihood of moderate- or high-severity fire [40].  A
lichen mat, a highly flammable and continuous fuel source at ground
level, develops within 40 years and is important in supporting fires in
jack pine forests [16].

Mature and immature jack pine forests have very different stand and fuel
characteristics and, therefore, exhibit different fire behavior.  The
mature jack pine fuel type in Ontario is characterized by 635 jack pine
per acre (1,569/ha) averaging 58 feet (17.7 m) in height, and 5.8 inches
(14.7 cm) in d.b.h. with an understory of black spruce [76].  The base
of live crown in mature jack pine forests is typically 33 feet (10 m)
above the ground surface [42].

After observing 12 experimental fires under different weather
conditions, Stocks [75] grouped fire behavior in the mature jack pine
fuel type into three categories:  (1) surface fires with slow to
moderate rates of spread, low to medium flame heights (0.3 to 3.3 feet
[0.1-1.0 m]), and a fire intensity less than 140 btu/s/ft ( less than 500 kW/m);
(2) vigorous surface fires with various degrees of torching or
intermittent crowning, flame heights about 6.6 feet (2 m), and fire
intensities of 140 to 870 btu/s/ft (500-3,000 kW/m); and (3) extremely
vigorous surface behavior with high rates of spread (33 feet per minute
[10 m/min]) that result in active crown fires with intensities over 1160
btu/s/ft (4,000 kW/m).  Because of the gap between the crown base and
the surface fuels, sustained crown fires in this fuel type are rare,
even with windspeeds above 16 miles per hour (25 km/h) at 33 feet (10 m)
above the ground surface [76].

The immature jack pine fuel type is characterized by 3,489 live jack
pine stems per acre (8,614/ha) averaging 26.9 feet (8.2 m) in height and
2.1 inches (5.3 cm) in d.b.h. with an understory of 3,953 dead,
suppressed jack pine stems per acre (9,760/ha) ranging from 7 to 20 feet
(2-6 m) in height [76].  The extremely dense nature of the stand and the
vertical fuel continuity make it difficult for fires to spread at even
moderate rate without crown fuels becoming involved [74].  Active crown
fires occur at intensities of 1,450 btu/s/ft (5,000 kW/m) [76].  This
fuel type crowns at a lower rate of spread than any other boreal forest
fuel type [42].  Of 12 experimental fires in immature jack pine stands,
the only two fires that did not crown had very low spread rates of 2.3
and 6.9 feet per minute (0.7 and 2.1 m/min), representing minimum
conditions for continuous fire spread in this fuel type.  The rate of
spread for the other 10 fires that crowned ranged from 26 to 162 feet
per minute (7.9-49.4 m/min) [74].  Short-term spread rates and
intensities as high as 223 feet per minute (68 m/min) and 17,350
btu/s/ft (60,000 kW/m) have been documented [76].

Temperatures during 18 surface fires in an open jack pine barren in
northern Ontario were recorded.  The ground vegetation consisted of
sweet-fern (Comptonia peregrina), blueberries (Vaccinium spp.), and
abundant lichen and moss.  Temperatures recorded at 2 to 4 inches (5-10
cm) above the ground ranged from 248 to 1013 degrees Fahrenheit (120-545
deg C).  Fires with temperatures greater than 662 degrees Fahrenheit
(350 deg C) occurred in dense vegetation with more than 0.7 ounce per
square foot (235 g/sq m) fuel dry weight.  High wind speeds appeared to
have a cooling effect on the fire temperatures [73].

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".

More info for the terms: duff, duff moisture code, fire intensity, forest, fuel, fuel moisture, full-tree harvesting, natural, prescribed fire, seed, seed tree, series, serotinous, tree, wildfire

Dense, young stands are extremely susceptible to crowning wildfire which
is hard to control.  A prescribed fire for the purpose of creating
Kirtland's Warbler habitat escaped control in 1980 at Mack Lake,
Michigan.  The fire crowned in a sapling stand, at times spread as fast
as 175 feet per minute (53 m/min), and did not slow down until it ran
out of jack pines and into hardwoods [70].

Prescribed fire is used in the jack pine type to prepare seedbeds,
reduce fire hazard, remove slash for easier planting, and/or open
serotinous cones in jack pine seed trees [55].  Slash has also been
burned in order to release seeds from cones in the slash.  This method
is ineffective, however, because if the fire is hot enough to prepare an
adequate seedbed, it destroys the cones [10,19].  Reproduction after
slash fires is often no better than on unburned clearcuts [23].

The seed tree silviculture method in conjunction with prescribed fire is
the most promising method for regenerating jack pine.  A prescribed
early summer fire serves to burn the slash, prepare a seedbed, and open
the serotinous cones in the seed trees [55].

While headfires may be more likely to open serotinous cones high in the
crowns of trees, backfires are generally recommended for use in
seed-tree systems because they move slower, may burn more humus, and are
safer [5,11].  However, in a series of prescribed fires in central
Ontario, backfires removed no more duff than headfires.  Drought
conditions were the the most important criteria in whether or not the
fire resulted in an adequate removal of humus [20].

Because of drier conditions, summer fires prepare better seedbeds than
spring fires [19,20,21].  If managers are relying on a natural seed
source, the prescribed fire should be timed early enough in the season
so that seedlings become well-established before winter [11], or late
enough so that seeds overwinter before germinating [5].  See Fire Case
Study for more information on prescribed fires in seed-tree systems.

Full-tree harvesting, in which a tree is delimbed at a landing, is
becoming a common practice.  This method leaves little slash to use as
fuel for seedbed-preparation prescribed fire.  However, if feather
mosses such as Schreber's moss are present, they will carry fire.  Spread
rates up to 164 feet per minute (50 m/min) over short distances were
observed in this fuel type, and prescribed fires have resulted in
statistically significant reductions in duff depth [56].

Dwarf-mistletoe (Arceuthobium americanum), which parasitizes jack pine
in the western part of its range, persists on dry ridges with sparse
undergrowth where fires are less severe and do not kill every tree.
Dwarf-mistletoe is eliminated if fire kills all of the trees.
Prescribed burning of logging slash and residual trees sanitizes an area
[6].  Seeds of dwarf-mistletoe are explosively discharged up to 60 feet
(18 m) from the canopy margin, so a minimum buffer of 66 feet (20 m) is
recommended between infected trees and new pine regeneration [61].

Equations were developed to predict the forest-floor moisture content
under jack pine canopies and in stand openings from the Duff Moisture
Code (DMC) and the Fine Fuel Moisture Code (FFMC) [26].  DMC and FFMC
are weather-based codes of the Canadian Forest Fire Weather Index System
[42].  The DMC and FFMC have also been calibrated to predict the
forest-floor moisture content of clearcut jack pine sites in relation to
slash distribution and by forest floor strata [25].

In one test, the Canadian Forest Fire Weather Index overestimated jack
pine wood slash moisture by a factor of 3.5 and variability by 50
percent, but was only 25 percent low on foliage moisture and 6 percent
low for its variability.  The U.S. National Fire-Danger Rating System
underestimated the wood and foliage moisture by 50 percent and
underestimated their variability by 30 percent [71].

Based on 12 experimental fires, Stocks [75] developed regression
equations for predicting the fire behavior in the mature jack pine fuel
type from the Canadian Forest Fire Weather Index System.  Frontal fire
intensity was strongly correlated with the Fire Weather Index (FWI).

More info for the terms: fuel, seed, serotinous

The study demonstrates that prescribed burning in conjunction with a
seed-tree system can successfully regenerate jack pine.  Enough heat was
generated from burning logging slash and the other fuel present to open
serotinous cones in the seed trees.  Jack pine regenerated successfully
on partially burned humus because of adequate precipitation during the
postfire growing seasons.  Had the fire been followed by a drought,
seedlings may have only survived on mineral seedbeds.

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More info for the term: phanerophyte

  
   Phanerophyte

More info for the terms: lichen, peat, permafrost, shrub, tree

Jack pine occurs on level to gently rolling sand plains of glacial
outwash, fluvial, or lacustrine origin.  It also occurs on eskers,
sand dunes, rock outcrops, bald rock ridges, and lake shores.  In the
Lake States, it commonly occurs between 1,000 and 1,500 feet (300-460 m)
in elevation with a maximum elevation of about 2,000 feet (610 m).  In
the East, jack pine grows near sea level to about 2,000 feet (610
m), with a population in New Hampshire occurring at around 2,500 feet
(760 m) [34,67].

Jack pine usually grows in dry, acidic sandy soils of the Spodosol or
Entisol Order, but it also grows in loamy soil, thin soil over bedrock,
peat, and soil over permafrost.  Although jack pine does not usually
grow in moderately alkaline soil, it can grow in calcareous soils up to
pH 8.2 if normal mycorrhizal fungi associates are present [67].

Common tree associates of jack pine not mentioned in Distribution and
Occurrence are bur oak (Quercus macrocarpa), northern red oak (Q.
rubra), red maple (Acer rubrum), balsam fir, white spruce (Picea
glauca), tamarack (Larix laricina), balsam poplar (Populus balsamifera),
bigtooth aspen (P. grandidentata), and quaking aspen (P. tremuloides)
[34].

Common shrub associates include prickly rose (Rosa acicularis),
bunchberry (Cornus canadensis), velvetleaf blueberry (Vaccinium
myrtilloides), mountain cranberry (V. vitis-idaea), bearberry (Arctostaphylos
uva-ursi), American green alder (Alnus crispa), Labrador tea (Ledum
groenlandicum), wintergreen (Pyrola spp.), and beaked hazel (Corylus
cornuta) [28,34,46,47,57].

Groundcover commonly consists of reindeer lichen (Cladonia spp.) on
drier sites and feather mosses, especially mountain fern-moss
(Hylocomium splendens) and Schreber's moss (Pleurozium schreberi), on
moister sites [16,34,57].

More info on this topic.

This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):

     1  Jack pine
    12  Black spruce
    14  Northern pin oak
    15  Red pine
    16  Aspen
    18  Paper birch

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This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):

   FRES10  White - red - jack pine
   FRES11  Spruce - fir
   FRES15  Oak - hickory
   FRES19  Aspen - birch

More info on this topic.

This species is known to occur in association with the following plant community types (as classified by Küchler 1964):

More info for the term: forest

   K093  Great Lakes spruce - fir forest
   K095  Great Lakes pine forest
   K100  Oak - hickory forest
   K108  Northern hardwoods - spruce forest

More info for the term: tree

Mature individuals survive low-severity fires [65].  Jack pine is
typically killed by crown fires or by moderate-severity surface fires
[37].  Alexander [7] found that double fire scars were fairly common in
jack pine, but triple fire scars were rare, suggesting that an
individual tree may survive only one or two surface fires in a lifetime.

More info for the terms: cover, lichens, tree, woodland

Jack pine provides food and cover for numerous wildlife species.  Jack
pine seeds are eaten by rodents and birds.  The stomach contents of red
squirrels, chipmunks, and white-footed mice showed that they had eaten
on average 392 seeds, 31 seeds, and 19 seeds apiece, respectively.
Red-backed voles also consume jack pine seeds [72].  White-tailed deer,
caribou, and snowshoe hares browse jack pine [12,68,80].  Woodland and
barren-ground caribou eat lichens growing on the ground and on tree bark
in jack pine stands [3,68].

The federally endangered Kirtland's warbler is endemic to jack pine
barrens.  Nests are located on the ground near or at the edge of fairly
dense young jack pine stands.  For further information on this bird and
its relationship to jack pine, see FEIS review of Kirtland's warbler.

More info for the terms: codominant, forest, tree, woodland

Jack pine is a dominant tree in the southern boreal forest region.
Associates are almost always subdominant except for aspen (Populus
spp.), paper birch (Betula papyrifera), and red pine (Pinus resinosa)
which may be codominant [34].

The following published classifications list jack pine as dominant or
codominant:

The vegetation of Alberta [57]
Field guide to forest ecosystems of west-central Alberta [28]
Virgin plant communities of the Boundary Waters Canoe Area [59]
Plant communities of Voyageurs National Park, Minnesota, U.S.A. [46]
The principal plant associations of the Saint Lawrence Valley [32]
The vegetation of Wisconsin [31]
Classification and ordination of southern boreal forests from the
   Hondo-Slave Lake area of central Alberta [47]
Jack pine-lichen woodland on sandy soils in northern Saskatchewan and
   northeastern Alberta [16]

More info for the term: tree

Tree

More info for the terms: cone, prescribed fire, seed, seed tree, tree

Jack pine is intensively managed for lumber in the Lake States.  Stands
are regenerated by planting, direct seeding, scattering cone-bearing
slash on mechanically scarified ground, or using the seed tree
silviculture method combined with prescribed fire.  Jack pine is also
managed to provide habitat for the federally endangered Kirtland's
Warbler.

Root borers, root feeders, shoot and stem borers, leaf feeders, needle
miners, and sucking insects affect the survival and growth of seedlings.
Many other insects feed on jack pine cones [67].  Young stands of jack
pine are susceptible to defoliation by the redheaded pine sawfly
(Neodiprion lecontei) [84].

The jack pine budworm (Choristoneura pinus) defoliates mature jack pine.
There is often a 20- to 30-year lag after major fire before the jack
pine budworm invades.  The regenerated stand does not produce abundant
cones on average for about 20 years and the jack pine budworm
population thrives in years of abundant cone production.  A model has
been developed to forecast the area to be infested with this pest [83].
In one study, all trees that died from jack pine budworm infestation had
roots infected with Armillaria root rot (Armillaria ostoyae) [52].

Jack pine is susceptible to many diseases including rust fungi [67].
Pine gall rust (Endocronartium harknessii) accounted for more than 99
percent of all stem rusts in a survey of 71 young jack pine plantations
in northwestern Ontario [43].

Jack pine browse is on average, by wet weight, 3.8 percent crude
protein, 4.2 percent fat, 15.1 percent crude fiber, and 22.2 percent
nitrogen-free-extract.  It is more digestible than northern white-cedar
(Thuja occidentalis) browse, although much less preferred [80].

     IL  IN  ME  MI  MN  NH  NY  VT  WI  AB
     BC  MB  NB  NT  NS  ON  PE  PQ  SK

Jack pine is planted for Christmas trees [17].

Jack pine browse is of intermediate preference to white-tailed deer [36]
and highly preferred by snowshoe hares in the winter [12].  Moose do not
prefer this browse, and it constitutes less than 1 percent of their diet
[8,30].  Caribou only browse jack pine occasionally; it constituted 1.7
to 3.9 percent air-dry weight of barren-ground caribou rumens in one
study [68].

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More info for the term: cone

Jack pine staminate and ovulate cone primordia are initiated in late
summer and then go dormant until spring.  Pollen shedding usually occurs
in late spring or early summer but is highly dependent on the weather.
Fertilization occurs 13 months after pollination.  Cones mature in late
summer or early fall, 2 years after initiation [67].

More info for the terms: competition, density, duff, fire severity, forest, hardwood, seed, severity, softwood

Serotinous cones opened by the heat of fire release jack pine seeds onto
seedbeds exposed by fire.  Jack pine establishment is limited primarily
by the depth of organic matter and, therefore, progressively increases
with greater fire severity [22,77].  The dead boles of the former stand
provide partial shade during the first few years of establishment
[18].

Regeneration is typically better after summer fires than spring fires.
In the Boundary Waters Canoe Area in Minnesota, a spring fire (The
Little Sioux Fire) occurred while the forest floor was still cool and
moist from snowmelt, and only the top few centimeters of duff were
removed.  In the first postfire growing season, jack pine seedling
density on three sites ranged from 0.86 to 1.58 seedlings per square
foot (9.3-17.0/sq m).  A summer fire (The Prayer Lake Fire) exposed
mineral soil almost everywhere and also destroyed many competing plant
seeds and reproductive structures.  Seedling densities on two sites
after the summer fire was 3.04 and 6.29 seedlings per square foot (32.7
and 67.6/sq m), considerably higher than the spring fire regeneration
[58].  On a Little Sioux Fire site, seedling density decreased from 0.91
seedlings/sq ft (9.8/sq m) in the first postfire year to 0.61
seedlings/sq ft (6.6/sq m) in postfire year 2 because of competition
[14].

In a 3-year study of postfire emergence of jack pine seed sown on two
recently burned seedbed sites, jack pine seeds germinated in the first 2
years after being sown, but not the third year.  On the wetter site,
37 percent of viable seed sown emerged the first year and 18 percent
the second year.  On the drier site, 14 percent emerged the first year
and 8 percent emerged the second year.  The seedbed may be more
favorable in postfire year 2 because of shade provided by regenerating
understory species.  The authors conclude that a 1-year delayed
emergence from soil-stored seed is an important strategy for postfire
jack pine regeneration [78].

Conflicting reports in the literature of the effect ash has on jack pine
germination may result from differences in type of ash and degree of
leaching.  Ash from burned surface organic matter is chemically neither
detrimental nor advantageous to the establishment of jack pine.  Wood
ash is detrimental because of its extreme alkalinity, and hardwood ash
is a poorer substrate than softwood ash.  Leaching of the ash improves
germination rates [79].

More info for the terms: crown residual colonizer, root crown, tree

   Tree without adventitious-bud root crown
   Crown residual colonizer (on-site, initial community)
   Initial-offsite colonizer (off-site, initial community)

More info for the terms: duff, forest, presence, seed, serotinous, tree

The minimum seed-bearing age of open-grown jack pine is 5 to 10 years.
Some seed is produced every year and serotinous cones accumulate in the
crown.  A mature stand of jack pine may have as many as 2 million seeds
per acre (5 million/ha) stored in unopened cones [35].  Because of
abundant seed production, few mature trees are necessary to regenerate a
stand.  Regeneration after fire in a balsam fir (Abies balsamea) forest
with only 5 relic jack pine per acre (12/ha) averaged 400 jack pine
seedlings per acre (1000/ha) in the first postfire year [74].

The serotinous cones, sealed shut by a resinous bond, require high
temperatures to open.  This heat is usually provided by fire, but hot,
dry weather (air temperatures of at least 80 degrees Fahrenheit [27 deg
C]) also opens some cones [67].  Because temperatures required to open
cones typically occur in the warmest part of the summer, survival of new
germinants may be poor because of drought conditions or lack of time to
become established before winter.

The winged seeds are the smallest of the native North American pines
[35] and are dispersed by gravity and wind.  The effective dispersal
range is about 110 to 130 feet (34-40 m) or two tree heights [53].

Seeds usually germinate rapidly after release when the 10-day mean
maximum air temperature is 65 degrees Fahrenheit (18 deg C) or higher
[35].  Jack pine seeds occasionally exhibit partial dormancy which is
probably broken naturally by heat from fire [4].  Seeds remain viable in
closed cones for years, but viability decreases over time.  Eyre and
LeBarron [35] found that 1- to 6-year-old cones had 78 to 89 percent
seed viability and cones over 5 years old had 62 percent seed viability.
Fifty percent of 20-year-old seeds may be viable [17].

Exposed mineral soil or thin residual humus of about 0.2 inch (0.5 cm)
or less provide the best seedbeds.  The presence of deeper humus has an
adverse effect on establishment; humus deeper than 1.5 inches (3.8 cm)
is a low-quality seedbed [22].  Successful germination and establishment
of jack pine usually occurs only after fire, but mechanical disturbance
may also expose adequate mineral seedbeds [33].  In northeastern
Minnesota, germination averaged 63 percent on mineral soil, 49 percent
on burned duff, 47 percent on scarified duff, and 17 percent on
undisturbed duff.  First-year survival of germinated seedlings was 84
percent on mineral soil, 70 percent on burned duff, 41 percent on
scarified duff, and 41 percent on undisturbed duff [35].

Germination and initial survival sometimes improve with partial shade,
but the positive effect of shade eventually becomes negative because
seedlings soon require higher light levels [10].  Mortality of
2-year-old jack pine seedlings was high under 11 and 20 percent of full
light, but minimal under 43 percent light and higher [69].  Seedling
survival may be low if drought conditions follow germination.  However,
in northeastern Minnesota, 3 consecutive days of 140 degree Fahrenheit
(60 deg C) surface temperatures for 2 hours did not result in
appreciable jack pine mortality [5].

During its first 20 years, jack pine is one of the fastest growing
conifers in its native range [67].  Maximum growth occurs under 43
percent light and higher [69].

Jack pine does not reproduce vegetatively.

Summer backfire/moderate-severity

More info for the term: fresh

The terrain was nearly flat with a slight south-southwest aspect.  The
glacial till soil varied downward from sandy loam to sandy clay loam.
The soil moisture regime was fresh to moderately moist, and the humus
(including surface moss and litter) averaged 2.8 inches (7.1 cm) in
depth.

More info on this topic.

More info for the terms: climax, codominant, frequency, wildfire

Obligate Initial Community Species

Jack pine invades areas where mineral soil has been exposed by major
disturbance such as fire [17].  It also rapidly invades newly formed
dunes after stabilization by grasses [60].  It is one of the most
shade-intolerant trees in its native range; only aspens, paper birch,
and tamarack are less tolerant [67].

Jack pine begins to show signs of decadence by age 75 [17], decreases in
frequency by 150 years, and may disappear completely after 200 years
[13], although some relic jack pine survive nearly 250 years [40].  In
the absence of fire, jack pine is succeeded by longer lived species such
as red pine (P. resinosa) or white pine, or by more shade-tolerant
species such as balsam fir and black spruce (Picea mariana).  Black
spruce, which often seeds in at the same time as jack pine, grows slower
but lives longer, becoming codominant after 90 years and eventually
succeeding jack pine [16,40,42].  On the driest, harshest sites, jack
pine may persist and form an edaphic climax [67].

Although generally occurring in even-aged stands that regenerated after
fire [34], some jack pine stands are uneven-aged.  Recruitment of jack
pine may occur fairly long after a fire if the stand is only partially
stocked.  In 65 percent of mature stands studied in northern lower
Michigan, the largest individuals differed in age by 10 to 23 years.
Two stands contained 40- to 45-year-old jack pines that had survived a
wildfire 10 years previously, a dominant intermediate class of 22- to
35-year-old pine regenerated after the fire, and numerous smaller
individuals from 4 to 20 years of age [1].  Zoladeski and Maycock [85]
suggest that recruitment of jack pine stops completely 50 years after
stand initiation, and that ultimate success is limited to the earliest
generation of jack pine.

Clearcutting alone or clearcutting followed by burning converts sites
previously dominated by mature jack pine to meadows dominated by Carex
spp. or early successional hardwoods, respectively [67]].

Pinus divaricata (Ait.) Sudw.

The currently accepted scientific name of jack pine is Pinus banksiana
Lamb. [48]. A rarely described shrubby form, P. b. forma procumbens
Rouseau, occurs in Quebec and Nova Scotia on rocky headlands [64].

Jack pine hybridizes with Rocky Mountain lodgepole pine (Pinus contorta
var. latifolia) where their ranges overlap in central and northwestern
Alberta and in scattered locations in Saskatchewan. The hybrid is P. X
murraybanksiana Righter & Stockwell [48].

More info for the terms: density, natural

Jack pine is adapted to acidic, dry, and sandy disturbed sites with a
lower pH limit of 4.0 [82].  In Ohio, jack pine is recommended for
planting on drier upper slopes, on moister and better drained lower
slopes, on all sandy and loamy mine spoils, and on clay spoils that have
a high proportion of coarse material [49].  This species has performed
well on anthracite spoils in Pennsylvania, with 48 percent survival at
age 10.  Survival was low (13 percent after 30 years), however, on coal
mine spoils in Missouri and Kansas.  In mixed plantings with hardwoods
in Illinois and Indiana, jack pine showed only 8 percent survival after
30 years [82].

Jack pine is recommended for planting on mined oil sands in northeastern
Alberta [16,39].  A planting density of 182 jack pine stems per acre
(450/ha) for tailing sands and 112 stems per acre (278/ha) for
overburden sites is recommended to provide 61 surviving stems per acre
(150/ha), a density considered sufficient for the natural perpetuation
of either a fully stocked jack pine stand or a mixed pine/deciduous
stand [39].

Jack pine is an important commercial timber species in the United States
and Canada.  The moderately hard and heavy wood is used for pulpwood,
lumber, telephone poles, fence posts, mine timbers, and railroad ties
[17,41].

The Jack Pine forest cover type (Society of American Foresters Type 1) (26) typically originates after forest fires. It is found in pure, even-aged stands or as a majority of the stocking over vast areas of Canada and to a much lesser extent in the Lake States and the northeastern United States (61). In the boreal forest jack pine is also a component of three other forest cover types-Black Spruce (Type 12), Paper Birch (Type 18), and Aspen (Type 16). In the northern forest region it is a component of two forest cover types-Red Pine (Type 15) and Northern Pin Oak (Type 14). Outliers near southern fringes of the species' range are found in various types of hardwood forest (12).

Associated tree species, listed in order of presence on dry to mesic sites, include northern pin oak (Quercus ellipsoidalis), bur oak (Q. macrocarpa), red pine (Pinus resinosa), bigtooth aspen (Populus grandidentata), quaking aspen (P. tremuloides), paper birch (Betula papyrifera), northern red oak Quercus rubra), eastern white pine (Pinus strobus), red maple (Acer rubrum), balsam fir (Abies balsamea), white spruce (Picea glauca), black spruce (P. mariana), tamarack (Larix laricina), and balsam poplar (Populus balsamifera). In the boreal forest the most common associates are quaking aspen, paper birch, balsam fir, and black spruce. In the northern forest they are northern pin oak, red pine, quaking aspen, paper birch, and balsam fir. Associates are nearly always subordinate to jack pine except for aspen, paper birch, and red pine which may be coordinate (26,61). Infrequent associates in the northeastern United States and adjacent Canada include white oak (Quercus alba), pin cherry (Prunus pensylvanica), gray birch (Betula populifolia), red spruce (Picea rubens), and pitch pine (Pinus rigida) (61).

In Canada, six subtypes of jack pine may be recognized based upon the edaphic and climatic conditions where they are found and on associated species as follows: jack pine-balsam fir-black spruce (subtype a); jack pine-feather moss (subtype b); jack pine-sheep laurel (subtype c); jack pine-sphagnum. (subtype d); jack pine-labrador-tea (subtype e); jack pine-lichen (subtype f) (26).

The preceding subtype descriptions apply primarily to eastern Canada. However, jack pine forests in Saskatchewan bear close resemblance to some of the subtypes described above (43).

Subtypes, as such, are not recognized in the Lake States. There are, however, certain variants of the type, including jack pine-black spruce, jack pine-red pine, and northern pin oak-jack pine (26).

In the eastern part of its range, jack pine grows in a maritime climate but elsewhere it is found in diverse continental climates characterized by short, warm to cool summers, very cold winters, and low rainfall. The average January and July temperatures range from -29° to -4° C (-20° to 25° F) and from 13° to 22° C (55° to 72° F), respectively. Average annual maximum temperatures range from 29° to 38° C (85° to 100° F), and average annual minimum temperatures are from -21° to -46° C (-5° to -50° F) (61). Mean annual temperatures range between -5° and 4° C (23° and 40° F) (74). The northern limits of the range closely parallel the 29° C (85° F) mean annual maximum isotherm. Frost may occur in some areas during any month and in the Northwest the range extends into the permafrost zone. (61).

Average annual precipitation ranges from 250 to 1400 mm (10 to 55 in) but 380 to 890 mm (15 to 35 in) are more usual. The average warm season precipitation ranges from 150 to 640 mm (6 to 25 in). Annual snowfall is from 76 to 508 cm (30 to 200 in), but over much of the range it is between 102 and 254 cm (40 to 100 in). Summer droughts are common in the south-central and western portions of the range (61).

The average date of the last killing spring frost ranges from April 30 to about July 1; and the average date of the first killing fall frost ranges from about August 10 to October 20. The frost-free period averages from 50 to 173 days but is usually from 80 to 120 days. Generally, temperature, rainfall, and frost-free period increase from the northwestern toward the southeastern part of the range (61).

Jack pine is subject to many agents that cause damage or mortality. Young jack pines are especially susceptible to early spring fires. Severe drought may kill many seedlings, particularly on coarse soils. All young jack pines less than 1.5 m (5 ft) tall and 55 percent of those from 1.5 to 3.7 m (5 to 12 ft) tall were killed by 123 days of flooding in northern Minnesota. Heavy populations of white-tailed deer can kill young jack pines up to 2.1 m (7 ft) tall, retard total height growth to half its potential, and deform most trees so they have little future value for timber products. Snowshoe hares can severely damage jack pine reproduction, particularly in dense stands in trees less than 4 cm (1.5 in) in d.b.h. (16,61). Jack pine seedlings are greatly damaged by elk in western Manitoba when animal populations are high, and meadow voles cause occasional damage and mortality by gnawing the bark off main stems and lower branches (16). Porcupines can cause extensive damage in older stands (74).

Numerous insects affect the survival and growth of jack pine seedlings (83). The more important groups of these are as follows: (1) root borers such as the pales weevil (Hylobius pales), pine root collar weevil (H. radicis), pine root tip weevil (H. rhizophagus), and Warren's collar weevil (H. warreni); (2) shoot and stem borers such as the northern pine weevil (Pissodes approximatus), the white pine weevil (P. strobi), and the Allegheny mound ant (Formica exsectoides); (3) leaf feeders such as numerous sawflies (Neodiprion sertifer, N. pratti banksianae, N. swainei, N. nigroscutum, N. compar, N. lecontei, N. dubiosus, N. nanulus nanulus), Diprion similus, jack pine budworm, pine chafer (Anomala oblivia), and pine webworm (Tetralopha robustella); (4) needle miners such as Argyrotaenia tabulana, Exoteleia pinifoliella, and Zelleria haimbachi; (5) root feeders including primarily white grubs (Phyllaophaga spp.); and (6) sucking insects such as two midges (Cecidomyia reeksi, and C. piniinopis), scale insects (Nuculaspis california, Chionaspis pinifoliae, and Toumeyella parvicornis), spittlebugs (Aphrophora parallela and A. saratogensis), and a wooly aphid (Pineus coloradensis).

The jack pine tip beetle (Conophthorus banksianae) causes extensive shoot tip mortality, preferring sapling-size trees. The lodgepole terminal weevil (Pissodes terminalis) attacks and destroys the new terminal bud of jack pine in Saskatchewan (61,83).

Several sawflies attack jack pine. Trees are often killed because the sawflies feed on both old and new needles. The pine tussock moth (Parorgyia plagiata) commonly defoliates large areas of sapling- and pole-size jack pine. The jack pine budworm is the most important defoliator of jack pine in the northeastern United States (61,84).

Several diseases commonly attack young jack pines and reduce survival and growth. A needle rust fungus (Coleosporium asterum) causes some defoliation of seedlings. Diplodia blight (Diplodia pinea) frequently results in a shoot blight of jack pine seedlings under nursery conditions. Sirococcus shoot blight (Sirococcus strobilinus) has also caused seedling losses in Lake States nurseries. Scleroderris canker (Gremmeniella abietina) causes serious losses in both nursery stock and young plantations. Before nursery control programs for this disease were instituted in the Lake States, this fungus killed an average of 40 percent of seedlings in plantations established with infected stock (77).

Jack pine is susceptible to a number of rust fungi that cause both growth loss and tree mortality. Many of these rusts are disseminated by infected nursery stock. The sweetfern blister rust (Cronartium comptoniae) sometimes kills many young seedlings and reduces the growth of survivors. More prevalent is the pine-oak (eastern) gall rust (Cronartium quercuum), which may infect up to 50 percent of young seedlings, killing many of the seedlings with galls on the main stem. Young jack pine in Minnesota have been severely cankered by stalactiform rust (Cronartium coleosporioides). In recent years the pine-to-pine (western) gall rust (Endocronartium harknessii) has been found throughout the Lake States in young jack pine stands. The importance of this rust is its potentially rapid rate of spread. This rust can infect directly from pine to pine without spending parts of its life cycle on an alternate host as do all the previously mentioned rusts (77).

Sapling- and pole-size jack pine frequently show severe needlecast (Davisomycella ampla). This fungus often causes loss of all but the current year's needles. Although affected trees suffer growth loss, the disease seldom causes mortality. Diplodia blight frequently kills branches and often the entire tree. This disease appears to be stress related and may reach epidemic status following drought. The European strain of scleroderris canker is currently killing many jack pine in northern New York and will cause serious losses if it reaches the major range of jack pine (77).

The rust fungi mentioned under seedling disease also cause extensive mortality in pole-size stands. The pine-oak (eastern) gall rust has caused severe losses in jack pine stands in northern Wisconsin. In some pole-size stands the disease is so prevalent that the stands have become worthless and have been destroyed (77).

The major root-rot fungi include the shoestring fungus (Armillaria mellea) and annosum root rot (Heterobasidion annosum) (77).

The principal wood decay organisms are Phellinus pini, Phaeolus schweinitzii, and Fomitopsis pinicola (77).

Windthrow is not a serious problem in jack pine stands except on shallow soils or when more than one-third of the stand basal area is removed in thinnings. Stem breakage from wind, ice, and snow is more common (10).

Cone and seed production can be decreased by numerous factors. Red squirrels and other rodents destroy cones and consume seeds (18,61,69,72). Low-vigor trees may produce much pollen but little seed. Pine-oak (eastern) gall rust damages trees resulting in smaller and aborted ovulate cones. Birds may be important consumers of jack pine seeds that fall to the ground or are directly sown (61). Cone and seed insects may cause serious losses. In one study in northeastern Wisconsin, numerous insect species were found attacking conelets and cones (57). The jack pine budworm (Choristoneura pinus pinus) destroyed 12 percent of the conelets. A mirid (Platylygus luridus) was observed piercing conelets as well as shoots and needles and was apparently responsible for a severe but unknown conelet abortion rate. The most prevalent insect attacking cones was the cone borer (Eucosma monitorana) which killed 10 percent of the cones. Other insects responsible for a total of about 4 percent cone mortality were the webbing coneworm (Dioryctria disclusa), red pine cone beetle (Conophthorus resinosae), jack pine budworm, and cone midges (Lestodiplosis graddator, Resseliella silvana, and Asynapta hopkinsi) (57).

Other insects that directly damage jack pine conelets, cones, or seeds, or that decrease their numbers by damaging potential cone-bearing shoots include the jack pine tip beetle (Conophthorus banksianae), shield-backed pine seed bug (Tetyra bipunctata), Virginia pine sawfly (Neodiprion pratti pratti), a moth (Holcocera immaculella), eastern pine seedworm (Laspeyresia toreuta), Nantucket pine tip moth (Rhyacionia frustrana), European pine shoot moth (R. buoliana), fir coneworm (Dioryctria abietivorella), and spruce coneworm (D. reniculelloides) (36).

Jack pine is a monoecious species. Ovulate cones are usually borne on primary and secondary branches in the upper tree crown and staminate cones are usually borne on tertiary branches lower in the crown. Ovulate cones are modified long shoots and staminate cones are modified dwarf shoots (24).

In northeastern Wisconsin, bud initiation for the following year's shoot systems begins in late June or early July. Staminate cone primordia are initiated in early or mid-July but ovulate primordia are not initiated until August. By early September the staminate cone primordia are about 1 mm (0.04 in) long and remain that size until spring. Then they elongate to about 5 mm (0.2 in) by the middle of May and early June just before pollen is shed. Rapid elongation up to several more millimeters occurs as the pollen is shed. Time of pollen shedding (anthesis) varies greatly from year to year depending on the weather (23).

Fertilization occurs about 13 months after pollination when the female cone is approaching its maximum size (27). Jack pine is normally a wind-pollinated, cross-fertilizing species but up to 25 percent or rarely more natural selfing can occur (29,64). Under natural conditions, however, survival of selfed and other inbred seedlings is severely reduced by natural selection against the semilethal and other deleterious characteristics carried by the inbred seedlings (67).

Cones mature and the seeds ripen late in the growing season of the year after pollination. Various cone and seed characteristics, including cone color, volume, fresh and dry weight, specific gravity, scale color, seed color, and embryo length, can aid in determining seed ripeness. In northeastern Wisconsin the best indicators of cone and seed ripeness are cone color, 75 percent brown; insides of the cone scales, reddish brown; seeds, dark brown or black; and cone moisture content, less than 45 percent of fresh weight. These indicators of cone and seed ripeness coincide with the beginning of cone harvesting by squirrels about September 10. Because specific gravity of the serotinous cones usually remains above 1.0 at least until February, flotation techniques cannot be used to evaluate cone and seed ripeness in jack pine (18).

The various environments in which jack pine grows over its wide range have provided ample opportunity for differentiation and natural selection (72).

Virtually the entire present range of jack pine was glaciated during the most recent Wisconsin stage that reached its maximum about 18,000 years ago. The present distribution of the species therefore results from re-invasion and migration over huge areas and great distances in a relatively short time, estimated at 15,000 years since the retreat of the ice began in earnest. Available paleobotanical evidence suggests that jack pine survived the Wisconsin glacial maximum at low elevations in the Appalachian Mountains south of latitude 34° N. and also in the western Ozark Mountains. From these refugia it migrated to the north and east and up the Mississippi Valley, and westward around the southern end of the Lake Agassiz basin (72).

During the first 20 years, jack pine in its native range is the fastest growing conifer other than tamarack (61). Seedlings reach 1.4 m (4.5 ft) tall in 5 to 8 years, depending on site. In the Lake States, 20-year-old stands with 2,470 trees per hectare (1,000/acre) on sites ranging from site index 12 to 21 m (40 to 70 ft) average between 5.5 and 9.8 m (18 and 32 ft) tall, 6.7 and 20.0 m² (29 and 87 ft²) in basal area, 5.8 and 10.2 cm (2.3 and 4.0 in) in d.b.h. (46), and 14 600 and 62 800 kg/ha (13,000 and 56,000 lb/acre) in ovendry weight of above-ground biomass (3).

The generalized equations used to derive these biomass estimates (3) give results similar to biomass production reported in other natural jack pine stands (22,32,37,51). Mean annual biomass production of 43-year-old natural jack pine stands in Quebec ranged from 1.42 to 2.47 t/ha (0.63 to 1.10 tons/acre) (28); in 7- to 57-year-old jack pine in New Brunswick from 0.94 to 2.76 t/ha (0.42 to 1.23 tons/acre) (51); and in 20- to 100-year-old stands in Ontario from about 1.17 to 3.38 t/ha (0.52 to 1.51 tons/acre) (45). In 24- and 25-year-old plantations in the Lake States, the highest mean annual biomass production was 58 percent higher than the maximum reported in the literature, when seed source and site were properly matched (89).

Annual height growth on medium sites (site index 17 m (55 ft)) in the Lake States averages from 33 cm (13 in) at age 30 to 23 cm (9 in) at age 50. At age 80 years, annual height growth is only 13 cm (5 in) (46) On typical sand plains sites, growth is about one site quality better where the water table is 1.2 to 1.8 m (4 to 6 ft) from the soil surface than where it is deeper (61).

Normally, mature trees are about 17 to 20 m (55 to 65 ft) tall and 20 to 25 cm (8 to 10 in) d.b.h., although some trees have attained 30 m (100 ft) in height and 64 cm (25 in) in d.b.h. (46,61), and one tree listed by the American Forestry Association in 1982 measured 73.4 cm (28.9 in) in d.b.h. and 25.6 m (84 ft) tall. Stand basal areas seldom exceed 37 m²/ha (160 ft²/acre) (46). Jack pine stands begin to disintegrate after 80 years on the best sites and after 60 years on the poorest sites. Vigorous trees 185 years old have been found in northwestern Minnesota, however. The oldest tree reported- 230 years old- was found east of Lake Nipigon in Ontario (61).

Growth is somewhat slower, but maintained longer, in Canada. Average stocking on sites having a site index range of 14 to 17 m (45 to 55 ft) in southern Manitoba produces a culmination of mean annual increment at 50 to 60 years with 1.6 to 3.2 m³/ha (23 to 46 ft³/acre) of merchantable material (9). For average site (site index 14 m (45 ft)) and stocking in Saskatchewan, mean annual increment culminates at about 70 years with 2.0 merchantable m³/ha (28 ft³/acre) (42). In fully stocked stands on average sites (site class 2) in Ontario, mean annual increment culminates at about age 60 with 2.7 m³/ha (38 ft³/acre) of merchantable material (54).

Yields from well-stocked, unmanaged jack pine stands in the Lake States at 60 years are shown in table 1 (46), along with yields from well-stocked unmanaged stands in Saskatchewan (42). Rotation age of 40 to 50 years is recommended to produce pulpwood and 60 to 70 years is recommended to produce poles and sawtimber.

Table 1- Yields of unmanaged jack pine stands in the Lakes States and in Saskatchewan by age and site index
Age
Height¹ Basal
area Total
volume Merchantable volume yr m m²/ha m³/ha m³/ha Lakes States Site index² 12.2 m 30    8.2 12.2   41 31 40 10.4 15.8   67 52 50 12.2 18.4   92 71 60 13.7 20.4 114 88 Site index 18.3 m 30 12.2 23.0 115   89 40 15.5 27.3 174 134 50 18.3 30.1 224 173 60 20.4 31.7 265 206 Saskatchewan Site index 10.1 m 30   5.8 11.7   45 10 40   8.2 14.0   66 34 50 10.1 15.8   85 56 60 11.9 17.0 102 75 Site index 17.4 m 30 11.6 19.3 112   61 40 14.6 23.2 140   98 50 17.4 26.2 168 134 60 19.8 28.2 195 165 ft ft²/acre ft³/acre ft³/acre Lakes States Site index 40 ft 30 27 53    580    448 40 34 69    956    736 50 40 80 1,311 1,008 60 45 89 1,631 1,264 Site index 60 ft 30 40 100 1,647 1,272 40 51 119 2,484 1,920 50 60 131 3,194 2,472 60 67 138 3,789 2,936 Saskatchewan Site index 33 ft 30 19 51    645    150 40 27 61    940    485 50 33 69 1,210    800 60 39 74 1,460 1,070 Site index 57 ft 30 38 84 1,600    865 40 48 101 2,000 1,403 50 57 114 2,405 1,910 60 65 123 2,785 2,360 ¹Mean height of dominants and codominants.
²Height of dominants and codominants at 50 years.

Jack pine is one of the most shade-intolerant trees in its native range. It is the least tolerant of its associated pine species and is slightly more tolerant than aspen, birch, and tamarack. Jack pine may be more tolerant in the seedling stage and often requires some shade on dry sites to reduce surface temperatures and evapotranspiration. Soon after seedlings are established, however, they should receive full sunlight to assure survival (10,61). Overall, jack pine can most accurately be classed as intolerant of shade.

Overstocked jack pine seedling and sapling stands with 4,950 or more trees per hectare (2,000/acre) should be weeded or cleaned (precommercial thinning) to improve growth and development. Otherwise such stands may stagnate because natural thinning in jack pine stands is slow except on the best sites (10). A study in northern Minnesota, wherein direct seeding produced a stand averaging 32,100 trees per hectare (13,000/acre) at age 5 years, compared the growth of no thinning with thinning to square spacings of 1.2, 1.8, and 2.4 m (4, 6, and 8 ft). Twenty-two years later the treatments averaged 9, 10, 13, and 15 cm (3.7, 4.1, 5.1, and 5.8 in) in d.b.h., respectively (14). Planting, direct seedings, and precommercial thinnings should have a goal of 2,000 to 3,000 trees per hectare (800 to 1,200/acre) by age 10 years (19,30).

Jack pine is a pioneer species on burns or other exposed sites. In the absence of fire or other catastrophes, jack pine is succeeded by more tolerant species, but on the poorest, driest sites it may persist and form an edaphic climax. In loamy sands and sandy loams in northern Minnesota, the usual succession is from jack pine to red pine to eastern white pine to a hardwood type composed of sugar maple (Acer saccharum), basswood (Tilia americana), and northern red oak. Frequently, the red pine and white pine stages are absent and jack pine is followed by speckled alder (Alnus rugosa), American hazel (Corylus americana), beaked hazel (C. cornuta), paper birch, and quaking aspen. This stage is followed by either the sugar maple-basswood association or spruce-fir. On loamy soils in northeastern Minnesota and parts of Canada, jack pine is succeeded by black spruce, white spruce, balsam fir, and paper birch. Eventually, the paper birch is eliminated from this association. In parts of northwestern Canada, jack pine may be replaced directly by white spruce; in parts of eastern Canada, the immediate succession may be to pure black spruce (10,26,61).

Jack pine frequently develops a taproot as a seedling and maintains it to maturity. During the first growing season under natural conditions the seedling root system penetrates to a depth of 13 to 25 cm (5 to 10 in). By the end of the second growing season jack pine seedlings on typical sandy soils in the open have a dry weight between 1 and 2 g (0.04 and 0.08 oz), have developed 8 to 10 cm (3 to 4 in) tops, and have root systems from 28 to 33 cm (11 to 13 in) deep and from 46 to 61 cm (18 to 24 in) wide. On a moist sandy soil with the water table about 76 cm (30 in) below the surface in Upper Michigan, roots penetrated to 53 cm (21 in) in 2 years but only to 61 cm (24 in) by 7 years; the lateral spread, however, increased from 0.9 to 1.2 m (3 to 4 ft) at 2 years to 4.3 to 4.9 m (14.0 to 16.2 ft) at 7 years. In the 7-year-old trees the average volume of the top, stem, branches, and foliage was about 4000 cm³ (244 in³) as compared to 1200 cm³ (73 in³) for the root system (61).

In northern Minnesota, root growth begins when the temperature reaches 4° C (40° F) in the upper 15 cm (6 in) of soil, usually within a week of the onset of shoot growth. Root growth ceases in the fall when soil temperature drops to 7° C (45° F) for 6 days or more. In some years root growth may begin in April and continue to late October. Seven-year-old trees elongated their lateral roots an average of 38 cm (15 in) in 1 year (61). In Manitoba, root development of jack pine growing on dry and fresh sands was confined mainly to the taproot for the first 1 to 3 years, but lateral branching became increasingly common on 3- to 4-year-old seedlings. Mycorrhizae were found on 1-year-old seedlings (16).

On deep, well-drained soils the roots may penetrate below 2.7 m (9 ft). Trees without distinct taproots usually have lateral roots that turn and grow downward as they approach other trees. The bulk of the root system, however, consists of laterals confined largely to the upper 46 cm (18 in) of soil; much of the root system is in the upper 15 cm (6 in) of soil. In 25-year-old jack pine stands in central Wisconsin, the dry weight of all roots in the upper 1.5 m (5 ft) of soil was 10 980 to 13 790 kg/ha (9,800 to 12,300 lb/acre) (61). A 40-year-old stand of jack pine in northern Minnesota produced 28 000 kg/ha (24,978 lb/acre), ovendry weight, of roots greater than 0.5 cm (0.2 in) and stumps less than 15 cm (6 in) tall (73).

Jack pine trees, particularly under good early growing conditions, begin to flower at a younger age than most other pine species (41,65,68). Under near optimum growing conditions in the greenhouse and nursery, female flowering can be induced in a small percentage of seedlings as early as 12 months from seed sowing (68). Male flowering under these conditions usually does not begin until the fourth year. An accumulated yield of 2,861,000 filled seeds per hectare (1,158,000/acre) can be produced through the first 8 years in plantations with 2.4 m (8 ft) between trees (67).

In naturally regenerated stands, jack pine typically begins to flower at 5 to 10 years under open-grown conditions but not until later in closed stands (61). Once cone production in jack pine begins, it is fairly regular and increases until crown competition becomes a factor. Seed production differs from year to year but some seed is usually produced every year and total crop failures are rare (31,61).

Seed yields per cone range from about 15 to 75 (72). Strongly curved cones yield less seed than straight ones (72). Ovulate abortion on the inner curvature of cones is twice that on the outer curvature (17). The average number of scales per cone can be more than 80 but usually only a little more than one-third of the scales, those in the upper end of the cones, bear seeds (72).

Over much of its natural range jack pine bears predominantly serotinous cones, but in the southern part cones are nonserotinous. Total seeds stored on the trees in serotinous cones can reach more than 14.6 kg or 4 million seeds per hectare (13.0 lb or 1.6 million/acre) in well stocked mature stands (61). As viability after 5 to 10 years may be significantly reduced, however, only cones 6 years old or less should be collected (8). Commercially cleaned seeds range between 156,500 and 551,000/kg (71,000 and 250,000/lb) with an average of 288,800/kg (131,000/lb) (45).

Well-stocked, mature stands in the Lake States dispersed an annual average of 6,670 to 25,950 seeds per hectare (2,700 to 10,500/acre) over 5 years; much of the total crop remained in the unopened cones. In areas with nonserotinous or partially serotinous cones, seed may be disseminated during any season. The effective range of seed dissemination, as measured by established seedlings, is about two tree heights although it is low beyond one tree height (61).

The melting temperature of the resinous bonding material of the cone scales is 50° C (122° F), but it is likely that the bonding resin softens at lower temperatures in the nonserotinous types in the southern portion of the species' range. The mechanism of cone opening in both serotinous and nonserotinous cones is hygroscopic. Once the bonding material of the cone scales is broken, the quantity of water in the scales is the limiting factor in scale movement and flexing outward under drying condition (35,61).

Jack pine cones open most readily during dry weather when the temperature is at least 27° C (80° F), although many of them remain closed until they are exposed to fire or high temperatures near the ground after wind breakage or logging. Over most of its range where serotinous cones are common, up to 50 percent may open on the sunny part of the crown. Cones may also open in very cold winters when the temperature is -46° C (-50° F) or colder (61).

Cone and seed crops in jack pine may be reduced by numerous agents (61). Rainy weather at time of pollination may reduce seed set. Cone and seed production are also reduced by cone and ovulate abortion (17,66), but the severe losses previously attributed to abortion may be partially the result of insect attacks. Within a cone, all the ovules near the base of the cone abort and abortion decreases toward the tip (17).

Germination is epigeal (45). Jack pine seed usually germinates within 15 to 60 days under favorable conditions (61), but some seeds require more than 100 days to germinate (72). Delayed germination of direct seeding increased stocking between the first and third year after sowing (60).

Under forest conditions with adequate moisture, seeds germinate when air temperatures reach 18° C (64° F) but light also influences germination (2,61). Under continuous light, germination was complete at a range of temperatures from 16° to 27° C (60° to 80° F) (2). Germination was markedly reduced at all temperatures when light was excluded. The shade cast by slash and snags on burned-over or cut-over areas to reduce surface temperature and drying undoubtedly contributes substantially to the good germination often observed on such areas (16).

Type of seedbed is an important factor affecting jack pine seed germination (16,61). In northeastern Minnesota, germination under clearcut and partially cut jack pine stands averaged 60 percent on mineral soil, 49 percent on burned duff, 47 percent on scarified and shaded duff, and 17 percent on undisturbed duff (61). The poor germination on litter and humus is caused by poor moisture conditions and it can be satisfactory in years of above normal precipitation. Germination may be delayed by spring drought (16). Associated species can affect germination, survival, and growth of jack pine differentially, probably as a result of allelopathy (13).

Survival on various seedbeds shows the same trend as germination (61). Optimum conditions for jack pine seedling establishment and survival are provided by mineral soil and burned seedbeds where competition from other vegetation is not severe (16), the water table is high, and there is some shade (61). Competition from shrubs and herbaceous vegetation, together with smothering by fallen leaves, are important causes of seedling mortality on sandy soils in Ontario. On clay soils in Manitoba and Saskatchewan, competition from aspen and hazel are responsible for poor survival. On similar soils in western Manitoba competing grasses kill many seedlings (16).

Most of the older jack pine stands appear to have been established following fires (61). Although jack pine seed usually germinates following fire, most of the seedlings die unless the organic matter left on the soil is less than 1.3 cm (0.5 in) thick. Most germination occurs the first and second season following fire, with most mortality between the first and second growing season. Unless conditions for germination and early survival are favorable, good regeneration does not necessarily follow burns (20,61).

Young seedlings grow tallest in full sunlight (48), although under stands their initial abundance may be greatest in light intensities of 11 to 30 percent of full sunlight, but no seedlings are found at 60 percent and higher crown cover (61).

Under forest conditions, seedling growth is slow in the first 3 years but increases rapidly beginning in the fourth and fifth years. Seedlings attain a height of about 5 cm (2 in) the first year, 15 cm (6 in) at 2 years, and 30 to 90 cm (12 to 36 in) at 4 years. Early growth of 2-0 seedlings in plantations is more rapid, amounting to 30 to 45 cm (12 to 18 in) per year on medium sites (61).

Shoot growth begins in late April and early May at Cloquet, MN, and Chalk River, ON (62,63,80), and about May 10 in the Upper Peninsula of Michigan (61). Essentially all height growth is completed in 61 to 68 days at the three locations. Maximum growth rate approaches 1 cm (0.4 in) per day in both Minnesota and Ontario. Although shoot growth in jack pine ceases long before the end of the frost-free season, the remaining time may be necessary to complete latewood growth, lignification, terminal bud development, and hardening off to resist frost (80).

If favorable moisture conditions prevail in late summer, jack pine frequently has a second period of shoot elongation and produces lammas and proleptic shoots (62,63). Trees with lammas shoots had a longer growth period than those without them but did not grow significantly less the following year. The late growth does not result in detectable increases in diameter growth and it may or may not result in false rings. Fall frost injury resulting in frost rings, however, may be frequent in the current shoots of trees with lammas growth.

Jack pine is usually found on sandy soils of the Spodosol and Entisol soil orders (81). It also grows on loamy soils, on thin soils over the granites and metamorphosed rocks of the Canadian Shield, over limestones, on peats, and on soil over permafrost (16,61,74).

Jack pine can grow on very dry sandy or gravelly soils where other species can scarcely survive, but it grows best on well drained loamy sands where the midsummer water table is from 1.2 to 1.8 m (4 to 6 ft) below the surface. Jack pine does not grow naturally where the surface soil is alkaline, but it does grow on soils overlying limestone. It can grow on calcareous soils (pH 8.2) if a normal mycorrhizal association is present. In southeastern New Brunswick, owing to a long fire history, jack pine occupies vast areas of clayey soils and it is more common than red pine on xeric sites that have high nutrient levels (61).

In well stocked stands in Minnesota and central Wisconsin, available moisture-holding capacity in the upper 30 cm (12 in) ranges from 3 to 17 percent by weight. Site index improves with an increase in fine sand and silt and clay in the upper soil layer, an increase in water-holding capacity (up to a point after which it levels off), and an increase in cation exchange capacity in the A and B horizons (61). Similar relations between these soil factors and site index were found for plantations in Wisconsin (82).

In a jack pine forest in northeastern Minnesota about 2580 to 3140 kg/ha (2,300 to 2,800 lb/acre) ovendry weight of organic matter was returned to the soil annually. The quantity of nutrient elements, expressed in percentage of dry weight, in freshly fallen jack pine litter averages as follows: calcium, 0.61; potassium, 0.16; phosphorus, 0.04; nitrogen, 0.58; and ash, 4.15. The litter is acid with a pH of 3.8 to 4.3 (61). Accumulated biomass of vegetation in jack pine stands more than 50 years old in northeastern Minnesota was 89 000 kg/ha (79,400 lb/acre) on shallow soils over bedrock, and 152 800 kg/ha (136,300 lb/acre) on deep till soils. Biomass of the forest floor was 35 200 kg/ha (31,400 lb/acre) on shallow soils and 50 300 kg/ha (44,870 lb/acre) on deep till soils. Nutrients in the vegetation, forest floor, and soil were similarly higher on the deep till soils (33). The above values largely agree with those found on other sites for jack pine forest floor biomass, litter fall, and nutrient transfer from jack pine forest to soil (28,49,78).

In the Lake States and Canada, jack pine grows most commonly on level to gently rolling sand plains, usually of glacial outwash, fluvial, or lacustrine origin. It occurs less commonly on eskers, sand dunes, rock outcrops, and bald rock ridges. In the Lake States jack pine is found chiefly at elevations between 300 and 460 m (1,000 and 1,500 ft), with a maximum of about 610 m (2,000 ft) above sea level. In the East, jack pine grows on a variety of sandy sites from near sea level up to about 610 m (2,000 ft), with an outlier in New Hampshire at 760 m (2,500 ft) (61).

The most notable special use for jack pine is as a breeding area for the Kirtland's warbler, a rare and endangered species. The Kirtland's warbler requires homogeneous stands of jack pine between 1.5 and 6 m (5 to 20 ft) tall (about 7 to 20 years old); stands are preferably larger than 32 ha (80 acres) (52).

Jack pine stands can be an important part of the visual resource for recreation areas; they stabilize watersheds, produce areas for blueberry picking, and provide food and shelter for wild game species, including the snowshoe hare and the white-tailed deer (10).

Under natural conditions jack pine does not reproduce vegetatively. Jack pine cuttings from young trees can be rooted but rooting ability decreases rapidly with increasing ortet age. Cuttings from 4-month-old seedlings gave 75 percent rooting (7) but average rooting was only 7 percent in cuttings from 6-year-old ortets and 5 percent in those from 10-year-old ortets (90). Clonal variation in rooting percentage ranged from 0 to 31.

Aryl esters of indole auxins can enhance rooting of jack pine cuttings taken from young seedlings. Phenyl indole-3-butyric (P-IBA) treatment caused 12 percent more jack pine cuttings to root than did treatment with indole-3-butyric acid (IBA), and up to 30 percent more than no treatment (34).

Rooting needle fascicles has potential for establishing large clones in a short time. Shearing the terminal buds on trees up to 5 years old induces the fascicular buds to differentiate and develops shoots. Treating such shoots from 2-year-old trees with IBA (0.1 percent) and placing them in a heated rooting medium under a 20-hour photoperiod resulted in up to 70 percent rooting (71).

Jack pine can be grafted, most successfully using dormant scions and when grafting is done just as the rootstock resumes growth in the spring. Both early and delayed graft incompatibility may occur; the causes are unknown (72). No complete jack pine plants have yet been propagated from either callus tissue or cell suspension cultures (72).

Pinaceae -- Pine family

T. D. Rudolph and P. R. Laidly

Jack pine (Pinus banksiana), also called scrub pine, Banksian pine, or Hudson Bay pine, is a small-to medium-sized coniferous tree of the northern forests of the United States and Canada, where it is an important source of pulpwood, lumber, and round timber (1,10,15,16). It grows farther north than any other American pine and is the most widely distributed pine species in Canada. It is a pioneer species in succession and invades areas where mineral soil has been exposed by major disturbances such as fires. It usually grows in even-aged pure or mixed stands on less fertile and drier soils than those required by other native species in its range (38).

The major portion of the jack pine range is in Canada where its northern boundary extends eastward from the Mackenzie River in the Northwest Territories across the country to Cape Breton Island, NS. The range then extends southwest through Maine, New Hampshire, northern New York, central Quebec and northern Ontario, Michigan, extreme northwest Indiana, northeast Illinois, then northwest through Wisconsin, Minnesota, Manitoba, Saskatchewan, central Alberta, to extreme northeast British Columbia (72).

Within its range, jack pine is widely but not continuously distributed. In Canada it is most abundant in Ontario, and in the United States, the largest acreages are in Minnesota, Wisconsin, and Michigan (74). The only significant artificial extensions of the jack pine range have been on strip-mined areas in the central and northeastern States (61) and on the sand hills of Nebraska (11).


- The native range of jack pine.

Tree, Evergreen, Monoecious, Habit erect, Trees without or rarely having knees, Tree with bark rough or scaly, Young shoots 3-dimensional, Buds resinous, Leaves needle-like, Leaves alternate, Needle-like leaf margins finely serrulate (use magnification or slide your finger along the leaf), Leaf apex acute, Leaves < 5 cm long, Leaves > 5 cm long, Leaves < 10 cm long, Leaves yellow-green above, Leaves yellow-green below, Leaves not blue-green, Needle-like leaves somewhat rounded, Needle-like leaves twisted, Needle-like leaf habit erect, Needle-like leaves per fascicle mostly 2, Needle-like leaf sheath early deciduous, Needle-like leaf sheath persistent, Twigs glabrous, Twigs viscid, Twigs not viscid, Twigs without peg-like projections or large fascicles after needles fall, Berry-like cones orange, Woody seed cones < 5 cm long, Woody seed cones > 5 cm long, Seed cones bearing a scarlike umbo, Umbo with missing or very weak prickle, Bracts of seed cone included, Seeds brown, Seeds black, Seeds winged, Seeds unequally winged, Seed wings prominent, Seed wings equal to or broader than body.

Jack pine (Pinus banksiana), also known as grey pine or scrub pine, is a North American pine.