Presence Of Spruce Research Articles

Сосновые (Pinus sylvestris) леса и редколесья Северо-Западного Приладожья

Сосновые (Pinus sylvestris) леса и редколесья Северо-Западного Приладожья

Сложные боры: ботанико-географические различия, происхождение, распространение

Composite pine forests with nemoral deciduous tree species (Carpinus betulus, Quercus robur, Tilia cordata) are widespread in the broad-leaved forest region of Eastern Europe. They occupy vast ancient alluvial plains with sandy and sandy loamy soils, river terraces, and along the latter they can «come» in the broad-leaved-coniferous zone. Based on the analysis of 187 relevés made in the Bryansk, Kaluga, Moscow and Smolensk Regions, the classification of composite pine forests using the Braun-Blanquet approach was carried out. As a result of the classification, two groups of communities of composite nemoral pine forests were identified. One of them is pine forests with oak and/or linden, united in the ass. Corylo avellanae–Pinetum sylvestris Bulokhov et Solomeshch 2003, the other represents nemoral-herb pine forests with a presence of spruce and some accompanying species and is assigned to the Pinus sylvestris facies of the nemoral-herb spruce forest of the ass. Rhodobryo rosei–Piceetum abietis Korotkov in Morozova et al. 2017. The participation of broad-leaved tree species in this syntaxon is small in any of the layers. Both associations belong to the class Carpino–Fagetea sylvaticae Jakucs ex Passarge 1968. On the latitudinal gradient, communities of the ass. Corylo avellanae–Pinetum sylvestris differ in the participation of oak and lime and the accompanying species, which is reflected in the identification of two subassociations: Corylo avellanae-Pinetum typicum (with oak), which is common in the zone of broad-leaved forests, and Corylo avellanae-Pinetum tilietosum cordatae (with lime) – in the southern part of the broad-leaved-coniferous forests zone. The origin of composite pine forests is debatable. Some researchers consider them as primary and quasi primary forests, and explain their formation and existence by various types of disturbances, both of anthropogenic (selective logging, anthropogenic fires, pine plantations) and natural (for example, fires) character. Disturbed composite pine forests with lower frequency of diagnostic association species and species of nemoral forest class were classified as variant Sambucus racemosa of the subass. Corylo avellanae–Pinetum typicum. Hazel pine forests with a nemoral composition and spruce in the forest stand and undergrowth (Pinus sylvestris facies of the ass. Rhodobryo rosei–Piceetum abietis) are found in the zone of broad-leaved-coniferous forests in the landscapes of moraine plains and formed in the places of planting pine cultures in the habitats of nemoral-herb spruce forests. It is difficult to assign individual communities to one or another syntaxon, especially near the border of two zones, and their differentiation is best seen when analyzing a large number of relevés.

Early Holocene presence of Norway spruce (Picea abies) on a high mountain nunatak in the Swedish Scandes: A further contribution to the biotic composition of the first deglaciated landscape and a link between past and present

A megafossil wood remnant of Norway spruce (Picea abies (L.) Karst.) was retrieved from a high-elevation nunatak in the southern Swedish Scandes. The site was nearly 600 m higher than the present-day treeline. These circumstances comply with analogous earlier recoveries, indicating presence of spruce at high elevations in the Scandes, several thousands of years prior to inferences made by pollen analysis. Radiocarbon-dating yielded a median age of 9300 cal a BP. This result adds firm detail and adheres to ongoing reappraisal of the structure and biodiversity of the late-glacial and early Holocene mountain landscape, in the light of growing megafossil and molecular genetic evidence.

Millennial-scale vegetation history of the north-eastern Russian Arctic during the mid-Pliocene inferred from the Lake El'gygytgyn pollen record

Abstract The 318-m long sediment record from Lake El'gygytgyn, NE Russia situated in the present-day herb tundra zone, provides a unique archive of high Arctic environmental changes since ca 3.6 million years ago (Ma). This paper focuses on pollen-derived vegetation change during the mid-Pliocene Warm Period (mPWP) and in particular during Marine Isotope Stage (MIS) M2, which is known to represent the coldest interval of the Pliocene. Building on initial pollen studies, we provide a more complete record and a more detailed discussion of climatically-driven vegetation and environmental changes in the northeastern Russian Arctic, spanning the 203-thousand-year interval between 3.383 and 3.180 Ma ago. Pine-spruce-fir-larch-Douglas fir forests dominated the area around Lake El'gygytgyn between 3.383 and 3.330 Ma (MIS MG4 - MIS MG2). Colder and drier climate caused a decrease of coniferous forests and widespread Sphagnum habitats around the lake between 3.370 and 3.357 Ma. After 3.3 Ma, the presence of spruce, fir and Douglas fir decreased again. A very pronounced cooling took place at the first half of MIS M2 (3.312–3.283 Ma), when treeless tundra- and steppe-like habitats became common in the regional vegetation. Climate conditions were similar or only slightly warmer and wetter to those of the Holocene. Numerous coprophilous fungi spores identified in the MIS M2 pollen samples suggest the presence of grazing mammals around the lake. Larch-pine forests with some spruce started to dominate the area again after ca. 3.282 Ma, thus pointing to a significant climate amelioration during the mPWP. However, the forested area decreased, while herb- and shrub-dominated vegetation spread again during MIS KM6 (especially 3.235–3.223 Ma), suggesting a noticeable climatic deterioration and relatively cold and dry conditions.

Pollen whiskers, rational limits and cryptic refugia: Determining the local presence of spruce on lateglacial landscapes of eastern Canada

The 20% spruce isopoll has traditionally been used to identify the range limit of spruce in eastern North America. Using plant macrofossils and stomates in a network of 25 lateglacial-aged sites throughout Nova Scotia, we identified sites where spruce was locally present but contributed as little as 4% to the pollen rain. Our data suggest that 8% pollen abundance is a more reasonable limit that consistently indicates the local presence of trees. Using 8% to define the presence of spruce, we find that the number of sites likely to contain spruce increases from 3 to 11 as compared to using the 20% isopoll. The resulting increase in the estimated distribution of spruce leads to a reduction in the apparent migration lags and migration rates of spruce into the region. Reducing the error in distribution histories will provide better-constrained estimates of climate change and its impact on the local vegetation.

Space sequestration below ground in old-growth spruce-beech forests—signs for facilitation?

Scientists are currently debating the effects of mixing tree species for the complementary resource acquisition in forest ecosystems. In four unmanaged old-growth spruce-beech forests in strict nature reserves in southern Sweden and northern Germany we assessed forest structure and fine rooting profiles and traits (≤2 mm) by fine root sampling and the analysis of fine root morphology and biomass. These studies were conducted in selected tree groups with four different interspecific competition perspectives: (1) spruce as a central tree, (2) spruce as competitor, (3) beech as a central tree, and (4) beech as competitor. Mean values of life fine root attributes like biomass (FRB), length (FRL), and root area index (RAI) were significantly lower for spruce than for beech in mixed stands. Vertical profiles of fine root attributes adjusted to one unit of basal area (BA) exhibited partial root system stratification when central beech is growing with spruce competitors. In this constellation, beech was able to raise its specific root length (SRL) and therefore soil exploration efficiency in the subsoil, while increasing root biomass partitioning into deeper soil layers. According to relative values of fine root attributes (rFRA), asymmetric below-ground competition was observed favoring beech over spruce, in particular when central beech trees are admixed with spruce competitors. We conclude that beech fine rooting is facilitated in the presence of spruce by lowering competitive pressure compared to intraspecific competition whereas the competitive pressure for spruce is increased by beech admixture. Our findings underline the need of spatially differentiated approaches to assess interspecific competition below ground. Single-tree approaches and simulations of below-ground competition are required to focus rather on microsites populated by tree specimens as the basic spatial study area.

Four millennia of woodland structure and dynamics at the Arctic treeline of eastern Canada

Paleoecological analysis using complementary indicators of vegetation and soil can provide spatially explicit information on ecological processes influencing trajectories of long-term ecosystem change. Here we document the structure and dynamics of an old-growth woodland before and after its inception 1000 years ago. We infer vegetation and soil characteristics from size and age distributions of black spruce (Picea mariana (Mill.) B.S.P.), soil properties, plant fossils, and paleosols. Radiocarbon ages of charcoal on the ground and in the soil indicate that the fire return interval was approximately 300 years between 2750 and 1000 cal. yr BP. No fire evidence was found before and after this period despite the presence of spruce since 4200 cal. yr BP. The size structures of living and dead spruce suggest that the woodland is in equilibrium with present climate in absence of fire. Tree establishment and mortality occurred regularly since the last fire event around 950 cal. yr BP. Both layering and occasional seeding have contributed to stabilize the spatial distribution of spruce over the past 1000 years. Since initial afforestation, soil development has been homogenized by the changing spatial distribution of spruce following each fire. We conclude that the history of the woodland is characterized by vegetation shifts associated with fire and soil disturbances and by millennial-scale maintenance of the woodland's structure despite changing climatic conditions.

Effect of natural disturbances on the abundance of Norway spruce ( Picea abies (L.) Karst.) regeneration in nemoral forests of the southern boreal zone

The impact of natural disturbances on the canopy (trees ≥14 m high) and sapling stratum (>0.3 and ≤14 m high) composition was studied in nemoral old-growth forests located within the southern boreal zone in Central Russia (Central Forest Reserve, 32°29′–33°01′E, 56°26′–56°31′N). I hypothesized that the current disturbance regime does not allow the maintenance of current spruce abundance in the canopy, and, as a result, there is a continuous shift in the canopy composition towards a greater abundance of deciduous species. Three 300×20 m 2 transects were established to estimate the proportions of stand under non-closed unexpanded canopy gaps. Data on sapling composition of 49 canopy gaps were used to analyze pattern of gap refuting in these forests. Additionally, data from three forest inventories showed changes in canopy composition over a period from 1972 to 1990. The current status of nemoral forests is characterized by the high proportion of stand area under treefall gaps (71%). The loss of spruce from the canopy caused by treefalls (53% of the total basal area of gap-makers) was slightly greater than its canopy abundance (45%). Canopy gaps of all sizes encouraged spruce regeneration which might be due to a decrease in sapling mortality and/or more active recruitment of spruce seedlings. After a gap was formed, the presence of spruce in sapling strata increased. However, within both small (<200 m 2 in size) and large (>200 m 2) gaps, tall (>6 m) spruce saplings did not reach the level of its abundance in the tree canopy. In gaps, tall (>6 m) saplings of lime ( Tilia cordata) and elm ( Ulmus glabra) grew more quickly than those of spruce and maple. These data suggested a decrease in canopy spruce and an increase in deciduous species in the near future which supported the original hypothesis. Analysis of forest inventory records revealed similar changes in the canopy structure over the past two decades. However, the observed high proportion of stand area under gaps implies that for the next few decades large areas of nemoral communities will be occupied by relatively young stands. This may, in turn, decrease the frequency of large-scale treefalls revegetated mainly by deciduous saplings.

Changes in Red Spruce Populations in Montane Forests of the Appalachians, 1982-1987

-A resurvey of red spruce (Picea rubens Sarg.) along 10.4 km of transects showed that between 1982 and 1987 there was a substantial increase in the proportion of dead canopy-sized spruce at elevations between 650 and 1220 m at three sites in the Adirondack, Green and White mountains of the northeastern United States. Overall, the percent of dead canopy spruce (>10 cm dbh and >1.37 m tall) along the transects increased from 26.1% in 1982 to 36.7% in 1987. Most of the mortality at higher elevations (>900 m) appears to have resulted from the death of individuals that were severely declining in 1982. There was no change in dead spruce or crown vigor between 1982 and 1987 at four of the six southern Appalachian sites. A decrease in crown vigor was observed at Mt. Mitchell (N.C.) and Roan Mt. (Tenn.), at least some of which was associated with damage from a recent ice storm. INTRODUCTION A marked decrease in the basal area and density of live red spruce (Picea rubens Sarg.) occurred in high-elevation (>900 m) spruce-fir forests of the northeastern United States between the mid-1960s and the early 1980s (Siccama et al., 1982; Johnson and Siccama, 1983; Scott et al., 1984; Johnson and McLaughlin, 1986). This reduction in live trees was concentrated in three regions of the northern Appalachian Mountain chain: the Adirondacks, the Green Mountains and the White Mountains. There is no agreement on the causes of the mortality which has most often been called a because several factors such as air pollution, climatic events and secondary pathogens are probably involved. A survey of 11 mountains in 1982 showed that there was about 25% standing dead spruce and extensive crown dieback of live trees at elevations above 900 m at five sites in the northern Appalachians and Adirondacks (Johnson and McLaughlin, 1986). In 1982, there was little evidence of severe dieback (death of needles and twigs in the live crown) below 900 m in the northern Appalachians, and no evidence of dieback or decline of red spruce at the southern Appalachian sites. In 1987 we repeated the 1982 study following the same sampling design to monitor changes over time in the proportion of dead and declining spruce trees in the region. METHODS Five northern and six southern Appalachian sites were sampled in each survey (Fig. 1). All forest sites were considered multiaged stands (Johnson and McLaughlin, 1986). Three of the northern sites, Mt. Mansfield (Vt.), Mt. Washington (N.H.), and Whiteface Mountain (N.Y.) were intensively sampled. At these sites, a total of 56 transects, 100 m long and parallel to the topographic contours, were located on Eand W-facing slopes at 50-m altitudinal intervals. Elevations were chosen to cover the widest range of spruce importance: the lower elevational limit of the transects was 650 or 700 m depending on the presence of spruce in the forest; the upper limit was usually 1150 m, which is near the upper limit of