Norway Spruce

Norway spruce
European spruce

More info for the terms: bog, forest, tree

Norway spruce is an introduced evergreen tree. In central Europe,
heights of up to 203 feet (61 m) have been reported [42]; the range is
usually between 100 and 200 feet (30-61 m) [87]. The bole is usually
straight and symmetrical, with no tendency to fork [42]. The bark of
young trees has pale fine shreds [50]. The bark of older trees is
usually heavy with algae and has shallow rounded scales that are easily
shed [17,50]. The crown of young trees is narrowly conic, that of older
trees becoming broadly columnar [50]. Secondary branchlets are
characteristically drooping or pendulous [2]. Norway spruce cones are
conspicuously large (4 to 7 inches [10-18 cm] long) [17]. The root
system is typically shallow, with several lateral roots and no taproot.
On rocky sites the roots spread widely, twining over the rocks. On bog
soils, Norway spruce tends to form plate-like roots [42]. In Finland, a
140-year-old Norway spruce forest in a Vaccinium-Myrtillus vegetation
type had a root zone extending only 12 inches (30 cm) into mineral soil [43].

Early growth of Norway spruce is slow, increasing to maximal rates from
20 to 60 years of age [42,50]. Within its native range, Norway spruce
remains healthy up to 200 years, and lives up to 300 to 400 years at the
northern limits of its range [42]. Senescence occurs at less than 200
years of age in the British Isles and North America [50].

Norway spruce is native to the European Alps, the Balkan mountains, and
the Carpathians, its range extending north to Scandinavia and merging
with Siberian spruce (Picea obovata) in northern Russia [50]. It was
introduced to the British Isles as early as 1500 AD, and is widely
planted in North America, particularly in the northeastern United
States, southeastern Canada, the Pacific Coast states, and the Rocky
Mountain states [47,50]. Naturalized populations are known from
Connecticut to Michigan and probably occur elsewhere [47].

More info for the terms: basal area, bog, density, fire frequency, fire regime, fire severity, fire suppression, frequency, natural, permafrost, severity, succession, taiga, tree

Norway spruce is not well adapted to survive fire. Fire in mature
stands of Norway spruce is usually of high intensity and destroys all
standing trees [15]. Fire severity usually depends on a number of
factors, primarily soil moisture [74]. In taiga forests over
permafrost, low-severity fires leaving standing live trees may
eventually result in complete stand destruction since windfall of the
remaining trees may occur when increased insolation on blackened soil
thaws the permafrost. There is little regeneration in stagnant stands
of Norway spruce; the next generation of trees is only produced after a
fire [15]. Norway spruce is easily killed by fire and is not an early
colonizer in postfire succession; stand-destroying fires usually result
in replacement by Scot's pine. Norway spruce develops as the understory
in Scot's pine stands on suitable sites, and will eventually replace
Scot's pine to complete the successional cycle [7,15,70].

Fire history in Norway: Fire was used extensively for agricultural
clearing in southeastern Norway 300 to 400 years ago. After a short
period of cultivation, depleted soils were left to natural
reforestation, forming mixtures of conifers and broadleaf trees, mostly
birch (Betula pubescens or B. verrucosa) [6]. In the pollen record,
Norway spruce pollen increased during periods of lower disturbance and
fewer fires. In the last 200 years, since agricultural burning has
virtually ceased, Norway spruce stands have formed closed canopies with
very little groundlayer vegetation [7].

Fire history in Finland: Fire frequencies have been estimated to range
from 31 to 81 years for different historical periods. Human activity
has played a large role in fire history; a large amount of burning
occurred during the Iron Age and medieval periods, mostly due to slash
and burn agriculture, from about 1 AD to 1750 AD [72]. Prior to the
appearance of cereal pollens, charcoal analysis of bog soils indicates
that, an average of one fire every 84 years occurred between 3000 and
2000 BP. There is an inverse relationship between the amount of Picea
pollen and the amount and frequency of charcoal particles; when fire
frequency is high, Norway spruce densities are low [73].

Fire history in Sweden: In northern Sweden, the mean fire rotation (the
amount of time equivalent to the area studied divided by the area of
sample plot burned annually) was approximately 100 years for mixed
stands of Norway spruce and Scotch pine from the end of the medieval
period up to the end of the nineteenth century. Since fire suppression,
the estimated fire rotation is on the order of 3,500 years. The
presuppression fire rotation created a mosaic of even-aged stands at
different successional stages. Norway spruce often forms the
undergrowth in Scotch pine stands that survive or are regenerated after
fire; Scotch pine often survives as an overstory tree and can reach very
old ages. In Norway spruce forests on wet sites fires have been rare;
fire-free intervals of up to 500 years have been reported for such sites
[21,84,85]. The mean number of years between fires and the amount of
time since the last fire were positively correlated to basal area of
Norway spruce; Norway spruce density increases when fires occur at long
intervals and shorter intervals favor Scotch pine [21].

Fire history in northern European Russia: Estimates from fire scar data
indicate fire frequencies on the order of 130 to 200 years in spruce
forests (including Siberian spruce and Norway spruce) [76].

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: cover, fire suppression, forest, litter, natural, prescribed fire, scarification, seed, swale

Prescribed fire has been used as a tool for forest regeneration in
Norway, primarily to prepare the ground for natural regeneration from
seed trees, usually Scotch pine. Management of Norway spruce in Norway
is often based on information from other countries where Norway spruce
and Scot's pine are the dominant conifers. After World War II, prescribed
fires were used to prepare sites for artificial regeneration, either for
sowing Scot's pine seeds or for planting Norway spruce nursery stock.
It is often difficult to conduct prescribed fires in Norway; the weather
is changeable and conditions are often too moist for burning. These
facts, coupled with increasing costs of burning, have led to a
preference for site scarification by mechanical means instead of fire
[6]. Prescribed fires are not used much in Finland today either, due to
high costs and variable weather [78]. The average size of individual
wildfires is usually greatest in mixed stands of Scot's pine and Norway
spruce [61].

Norway spruce is known as a nutrient-demanding species; this has led to
concern that prescribed fire for site preparation burns too much of the
humus and results in soils that are not favorable for good Norway spruce
growth. In Norway, Norway spruce seedlings showed good 12-year survival
on both burned (83 percent survival) and unburned (78 percent survival)
sites. Overall height growth on unburned sites was slightly better at
12 years than on burned sites, although early growth on burned sites was
better [6]. In Sweden, sites that were clearcut and burned, then seeded
with Norway spruce were compared with similar sites that had not been
burned. The unburned sites had thicker humus layers after 43 years of
growth. The authors estimate that it takes 70 to 80 years from the time
of the fire for burned humus layers to be rebuilt to prefire levels [37].

Prescribing fire for site preparation in Scandinavia depends on the
vegetation type. Types that are characterized by thick, raw humus
layers benefit from fire, which releases nutrients and activates the
humus [6,74]. After fire passes over humus, ashes and carbonized plants
form a thin cover over the otherwise undamaged humus layers [74].
Prescribed fires used for site preparation must be conducted with care
to prevent destruction of humus and excessive heating of upper mineral
soil. Fires temperatures of 662 degrees Fahrenheit (350 deg C) or less
at the soil surface will release nutrients stored in litter and allow
them to condense in the humus and upper mineral soils [28]. Fires that
burn quickly enough to leave humus may be acceptable. Decomposition
rates in northern Norway spruce forests are very slow. In Finland, 56
years after logging, even very thin branches are left intact in slash
and litter [54]. Prescribed fires can release some of this organic
matter, and increase the pH of the soil. Some nutrients are lost to the
atmosphere [78]. Types with thin humus layers are better unburned,
since the humus would be destroyed by fire [66,79]. Norway spruce is
unsuited for such sites, since its shallow roots render it less able to
exploit the mineral soil for nutrients than Scotch pine [37].
Prescribed burning is usually not necessary on most fertile soils, but
may be useful on sites that have experienced swale cultivation [79].

Fire suppression in Sweden since the nineteenth century has resulted in
an over-representation of aging Norway spruce forests, and it has been
recommended that prescribed fires for stand rejuvenation are necessary
in Swedish National Parks and nature reserves to improve stand health by
reestablishing a mosaic of seral stands [84].

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More info for the term: phanerophyte

Phanerophyte

More info for the term: forest

Norway spruce grows best in cool, humid climates on rich soils [2,17].
Preferred soils include well-drained sandy loams [2,17,42]. It also
grows well on almost all other types of soils. Permanently waterlogged
soils inhibit Norway spruce growth, but Norway spruce does occur on
poorly drained soils and in bogs [42]. Growth rates increase with
increased soil organic material and are positively correlated to the
nitrogen content of the soil. In southern Finland, soil pH under 34- to
38-year-old plantations of Norway spruce ranged from 3.7 to 4.4. Norway
spruce is also found on podzolized soils [45].

Norway spruce occurs at elevations up to 6,560 feet (2,000 m) in the
Bavarian Alps, to 4,920 feet (1,500 m) in the Black Forest, and to 3,450
feet (1,051 m) in the Fichtel Mountains [42]. In Switzerland, the
'hilly zone' up to 1,800 feet (550 m) is occupied by mixed hardwoods
with scattered conifers (European silver fir, Norway spruce and Scot's
pine); the 'mountain zone' from 1,800 feet to 3,800 feet (550-1,160 m)
is cooler and more humid and is dominated by European beech, European
silver fir and increasing amounts of Norway spruce; the subalpine zone
from 3,800 feet to 6,600 feet (1,160-2,000 m) is divided into two
subzones: 'subalpine spruce' up to 5,500 feet (1,670 m) consisting of
pure Norway spruce and mixed Norway spruce and European silver fir; and
the 'Arolla pine (Swiss stone pine [Pinus cembra])- (European) larch
(Larix decidua) zone' from 5,500 feet (1,670 m) to timberline [24].
This distribution is generally applicable to most of central Europe [42].

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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):

FRES11 Spruce - fir
FRES15 Oak - hickory
FRES18 Maple - beech - birch
FRES19 Aspen - birch

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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

K096 Northeastern spruce - fir forest
K104 Appalachian oak forest
K106 Northern hardwoods
K107 Northern hardwoods - fir forest
K108 Northern hardwoods - spruce forest
K109 Transition between K104 and K106

More info for the terms: forest, prescribed fire

Norway spruce is easily damaged or killed by fire [74]. The crown
canopy of Norway spruce is often totally destroyed by even minor surface
fires [64,76]. However, there are almost always scattered survivors
even following crown fires; in most cases survival is due to local
topography which prevents fire spread [82]. In Finland, forest fire
damage is greatest in Norway spruce forests (compared with mixed or pure
Scotch pine stands) [61]. In the United States, grass fires are
reported to cause severe damage to Norway spruce plantations [17].

Norway spruce seeds buried in humus at 1.2 inch (3 cm), 1.9 inch (5 cm),
and 3.9 inch (10 cm) depths were undamaged by the heat of a prescribed
fire that measured 820 degrees Fahrenheit (438 deg C) at the soil
surface. The humus provided excellent insulation; the temperature at
1.2 inches (3 cm) was only 80 degrees Fahrenheit (26.5 deg C) [74].

In a laboratory study in which heated air was applied to stem sections
and to whole tops of dormant 3- and 4-year-old Norway spruce seedlings,
Norway spruce was found to be more tolerant of heat than European larch
or Japanese larch (Larix leptolepis). Active Norway spruce seedlings
were more heat tolerant than European and Japanese larch, eastern white
pine (Pinus strobus), Scotch pine, or American beech (Fagus
grandifolia), but none were very tolerant. In this experiment, no
seedlings were killed by the heat treatment, but dormant Norway spruce
seedlings were almost completely defoliated [39].

More info for the term: cover

Norway spruce seedlings are highly preferred winter browse for snowshoe
hares in Quebec. Browsing of seedlings and saplings in plantations can
be intense, as young plantations form ideal winter habitat for snowshoe
hares [3]. Norway spruce is not a preferred browse for moose in
Scandinavia; young and middle-aged stands of Scotch pine form habitat
preferred by moose over mature Scotch pine-Norway spruce forests and
bogs [14]. In Europe, red deer strip the bark of Norway spruce [60].
Other animals browse spruce foliage but it is not a highly preferred
food source for either wildlife or domestic animals [87]. Norway spruce
provides important winter cover for a number of species of wildlife
[80]. Grouse eat spruce leaves and the seeds are consumed by a number
of birds and small mammals [86,87].

In its native range, Norway spruce occurs in pure stands, transitional
stands mixed with Scotch pine (Pinus sylvestris), or mixed stands with
European beech (Fagus sylvatica) and European silver fir (Abies alba).
Scattered Norway spruce occurs in seral stands of European aspen
(Populus tremula) or hairy birch (Betula pubescens). Classification
systems for Scandinavian forests where Norway spruce and/or Scotch pine
are the major species are based on ground vegetation [11]. Common
groundlayer species include bilberry (Vaccinium myrtillus), lingonberry
(V. vitis-idaea), heather (Calluna vulgaris), and woodsorrel (Oxalis
spp.) [5]. Good sites for Norway spruce occur on Oxalis-Myrtillus
types and fair sites are indicated by Myrtillus. Vaccinium types are
usually rather barren and not suited for good spruce growth [79].
Understory species most often associated with Norway spruce in Poland
include raspberry (Rubus idaeus) and European mountain-ash (Sorbus
aucuparia). Mature Norway spruce forests typically have very little
groundlayer vegetation [5].

More info for the term: tree

Tree

More info for the terms: forest, litter, natural, scarification, selection, tree

Norway spruce is the most intensively studied spruce in the world. A
number of geographic races have been identified, and numerous genetic
improvement programs are underway, mostly in Europe and Scandinavia
[87]. In Europe, Norway spruce is the focus of increasing concern about
forest decline. It is exhibiting a specific set of symptoms
("Waldsterben") which are also showing up in forest trees in the United
States (including red spruce [Picea rubens] and Norway spruce)
[40,46,55,66]. These symptoms include needle chlorosis combined with
magnesium deficiency and thinning of the crown [46]. Explanations
usually center on air pollution (ozone, acid deposition, or toxic metals
contamination) coupled with acidified, depleted soils that cause, among
other problems, foliar magnesium deficiency [12,46,55,58,66].

Soils under Norway spruce stands are often more acidic than soils under
other species. Soil acidity appears to increase with stand age as soil
buffering capacity decreases with age [4].

Norway spruce is not windfirm and is also subject to snowbreak [42].

Artificial Reforestation: Norway spruce has been widely planted in
reforestation programs in the eastern United States [2]. In Ontario,
expected rotation of Norway spruce ranges from 60 to 70 years. Sites
are prepared by plowing, and Norway spruce seedlings are planted with 5 x
5 foot spacing (1.5 x 1.5 m) [19].

Silviculture: In Europe, Norway spruce is usually managed with
selection systems in mixtures with European beech and European silver
fir, particularly on private holdings. Such mixtures require frequent
thinning to maintain European silver fir, which would otherwise be
eliminated by the beech and Norway spruce [67]. Norway spruce is also
managed with even-aged systems such as patch clearcutting and
strip-cutting [49]. In Sweden, single-tree selection has been of
limited use, but a recent report suggests that it is possible to obtain
abundant regeneration and high ingrowth rates in selection stands with
high levels of standing volume [48]. Scotch pine can be planted as a
nurse tree for Norway spruce; such mixtures result in a net gain in
production over monocultures of either species [10]. During dry
summers, spruce litter buildup can create manganese concentrations that
prevent regeneration of Norway spruce. As a consequence, land managers
in France alternate rotations of Norway spruce and hardwoods, or destroy
the toxic manganese in litter by scarification [20].

Norway spruce is resistant to mistblown glyphosate used to kill
competing hardwoods [81].

Fertilization of Norway spruce can promote frost damage by prolonging
the growing season, and delaying cuticularization of the epidermis [68].

Whole-tree harvesting in Sweden is deleterious to soil fertility and
lowers soil pH [53].

In Belgium, Norway spruce was excluded from heathlands (Calluna
vulgaris) created by burn-beating cultivation (cutting, piling and
burning humus layers to fertilize fields), mowing, and sheep grazing.
Norway spruce has been planted on these former heathlands, and
burn-beating agriculture is no longer practiced. Since burn-beating
removes the humus layer these Norway spruce plantations are growing on
severely depleted soils. Depleted soils may be contributing to
Waldsterben in these plantations, and may also present problems for
future rotations [25].

In Finland, 15- to 20-year-old natural stands of Norway spruce were
frost hardy (defined as the temperature at which 50 percent mortality of
bud occurs) to 24.8 degrees Fahrenheit (-4 deg C) in mid-summer, and
frost hardy to -54.4 degrees Fahrenheit (-48 deg C) in January.
Hardening occurs over a short period in September, and is lost over a
short period in early May [59].

Insect Pests: In North America, Norway spruce is host to western spruce
budworm [13] and mountain pine beetle [32].

CT HI IL IN ME MA MI NY PA

Norway spruce has been planted for windbreaks and shelterbelts in
western prairies, although it grows better in more humid environments
[17]. It is recommended for shelterbelt plantings in humid,
severe-winter regions [2]. Norway spruce is widely planted for
Christmas trees and as an ornamental [17].

Norway spruce roots can be used as grafting stock for white spruce
(Picea glauca) [52].

Norway spruce resin has been used to make Burgundy pitch, and the twigs
used to make Swiss turpentine. The twigs and needles were used to make
antiscorbutic and diuretic beverages [87].

Norway spruce nursery stock is of extremely low preference to
white-tailed deer when compared with other ornamental species, including
both conifers and hardwoods [18].

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Norway spruce cones open from May to June. Seeds ripen in late autumn
the same year. They are released on warm days in late autumn and
winter, but are sometimes retained until spring [42].

Norway spruce seedlings are not usually present on burned areas; the
soils are usually too dry and hot to support good seedling establishment [74].

Tree without adventitious-bud root crown

More info for the terms: layering, natural, seed, tree

Sexual reproduction: Norway spruce usually first reproduces at 30 to 40
years of age. Good seed crops are produced every 3 to 4 years in
Britain, 8 to 10 years in Norway, and 12 to 13 years in Finland [42,87].
Most of the seeds are produced in the crowns of dominant stems; seed
yield is lower in smaller stems in stands of the same age. Norway
spruce seeds are wind dispersed, but do not usually travel much farther
than the height of the parent tree [42]. Movement after dispersal,
however, can be considerable when seeds are dispersed onto crusted snow
and are pushed along on the surface by wind [34,74]. Seeds of Norway
spruce germinate promptly and do not require pretreatment or exacting
light regimes. Moist chilling of some spruce (Picea spp.) seeds removes
the requirement for light [87]. Optimum germination temperature for
Norway spruce seeds is around 73 degrees Fahrenheit (23 deg C) but
germination will occur up to about 91 degrees Fahrenheit (33 deg C)
[42]. Seedling growth is best at constant low temperature (48 degrees
Fahrenheit [9 deg C]), rather than with fluctuating temperatures or
steady high temperatures [36]. The seedlings are sensitive to drought
and/or overheating, particularly when the soil surface is exposed to
direct insolation [42]. In Utah, nursery-grown seedlings inclined to
the south (to shade the soil directly under the seedling and keep the
roots cooler and wetter) averaged 6 percent mortality from heat damage,
whereas seedlings inclined to the north averaged 30 percent mortality
from the same cause [41]. Other studies support the hypothesis that
shading improves early seedling survival [33,77]. Thin humus (as
opposed to thick humus) hinders Norway spruce establishment since it
dries out more quickly and contributes to drought stress of the
seedlings [70].

Vegetative reproduction: Under natural conditions, particularly in
areas of high humidity and high soil moisture, Norway spruce reproduces
by layering [42]. It does not sprout from stumps or roots [65].

Norway spruce can be propagated by cuttings and micropropagation
techniques [30].

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More info for the terms: climax, forest, natural, succession

Obligate Climax Species

Norway spruce is tolerant of shade. Norway spruce stands form the
climax forest of Scandinavia but stagnate with age [79]. Seeds of
Norway spruce are probably not long lived in the soil, although under
good storage conditions remain viable for up to 7 years [87]. The soil
seedbank under a 100-year-old Norway spruce forest in Russia contained a
large number of viable seeds of mostly early successional species. It
was not representative of the aboveground flora and apparently did not
contain many Norway spruce seeds [38].

Disturbance events such as windfalls, snow damage, disease and insect
attack create small-scale gaps in the mature canopy. Norway spruce
depends largely on advance regeneration (seedling banks) to capture such
canopy gaps [56]. Norway spruce is the most common gapmaker and it is
also the most common seedling in gaps. Seedlings survive in an
extremely stunted condition for many years. This reservoir of seedlings
functions in a way analogous to soil seedbanks [29]. Suppressed Norway
spruce saplings can persist for several decades, retaining the ability
to respond to canopy gaps with increased growth [35]. In Sweden,
suppressed Norway spruce trees less than 8.2 feet (2.5 m) tall and 100
to 220 years old exhibited new growth during gap-phase replacement [70].
In Bavarian Norway spruce stands, storm-caused windfall disturbances
were followed by new Norway spruce stands that were older than than the
windfall event (indicating advance regeneration). Sites that had been
cleaned (removal of dead trees and broken stems) had a birch-dominated
regeneration layer that originated after the windfall event. Spruce
seedlings were probably damaged by the cleaning operation [23]. In
northern Sweden, Norway spruce-hairy birch forests consist of all-aged
(up to 330 years) Norway spruce (largely as a result of gap-capture
replacement) [35].

Norway spruce first occurred in Scandinavia approximately 2,500 years
ago; its immigration from Europe is attributed to colder Scandinavian
winters coupled with increased precipitation and storm events which
allowed Norway spruce to colonize areas that were formerly too dry [7].
It survived in Scandinavia in low densities due to frequent disturbances
until climatic changes coupled with a decrease in human-caused
disturbances (mainly fire) allowed natural succession to proceed,
resulting in the current widespread distribution of dense Norway
spruce-dominated forests [8].

Picea excelsa Link [47,50]

The currently accepted scientific name of Norway spruce is Picea abies
(L.) Karst. [47]. There are no currently accepted infrataxa, although a
number of cultivars exist [50].

Norway spruce was planted on surface mine spoils in Indiana from 1928 to
the 1960's [9]. It tolerates acidic soils but is not well suited for
dry or nutrient deficient soils [80].

Norway spruce wood is strong, soft, straight- and fine-grained, and
easily worked [17,87]. It is not durable in contact with soil. It is
widely used for construction, pulp, furniture, and musical instruments
[17,80]. Norway spruce is one of the most common and economically
important coniferous species in Europe and Scandinavia [46]. In Maine,
thinned material and standing dead Norway spruce produced pulp of good
strength as reported in a study of the pulp potential of seven softwoods [16].