Effect of chronic ammonium nitrate addition on the ectomycorrhizal community in a black spruce stand1This article is one of a selection of papers from the 7th International Conference on Disturbance Dynamics in Boreal Forests.

2012 ◽  
Vol 42 (7) ◽  
pp. 1204-1212 ◽  
Author(s):  
Sergio Rossi ◽  
Adam Bordeleau ◽  
Daniel Houle ◽  
Hubert Morin
Keyword(s):  
Ammonium Nitrate ◽  
Boreal Forests ◽  
Black Spruce ◽  
N Deposition ◽  
Fungal Species ◽  
Root Tip ◽  
Soil Conditions ◽  
Root Tips ◽  
Atmospheric N Deposition ◽  
Host Trees

Observed modifications of ectomycorrhizal (ECM) communities have been connected to the increased N depositions of the 20th century. Because of their narrow niche width, small disturbances of soil conditions can produce greater effects on the fungal species than on their host trees. This study investigated the ECM community in a black spruce ( Picea mariana (Mill.) BSP) stand subjected to long-term additions of 9 and 30 kg N·ha–1·year–1 of ammonium nitrate, representing 3 and 10 times the atmospheric N deposition at the site, respectively. Root tip vitality and ECM presence were detected on samples collected from the organic horizon and ECM were classified into morphotypes according to their morphological and anatomical characters. In the control, 80.6% of the root tips were vital, 76.5% of them showing ECM colonization. Higher root tip vitality and mycorrhization were observed in the treated plots. Forty-one morphotypes were identified, most of them detected at the higher N inputs. Results diverging from the expectations of a reduction in ECM presence and diversity could be related to a higher growth rate of the trees following fertilization. The repeated application of small N doses could have been a better imitation of natural inputs from atmospheric deposition and could have provided more reliable responses of ECM to treatment.

scholarly journals Nitrogen balance of a boreal Scots pine forest

2012 ◽  
Vol 9 (8) ◽  
pp. 11201-11237 ◽  
Author(s):  
J. F. J. Korhonen ◽  
M. Pihlatie ◽  
J. Pumpanen ◽  
H. Aaltonen ◽  
P. Hari ◽  
...  
Keyword(s):  
Scots Pine ◽  
Boreal Forests ◽  
N2o Emission ◽  
N Deposition ◽  
Organic N ◽  
N Availability ◽  
Atmospheric N Deposition ◽  
Drainage Flow ◽  
Nutrient Pools ◽  
Scots Pine Forest

Abstract. The productivity of boreal forests is considered to be limited by low nitrogen (N) availability. Increased atmospheric N deposition has altered the functioning and N cycling of these N-sensitive ecosystems. The most important components of N pools and fluxes were measured in a boreal Scots pine stand in Hyytiälä, Southern Finland. The measurement at the site allowed direct estimations of nutrient pools in the soil and biomass, inputs from the atmosphere and outputs as drainage flow and gaseous losses from two micro-catchments. N was accumulating to the system with a rate of 7 kg N ha−1 yr−1. Nitrogen input as atmospheric deposition was 7.4 kg N ha−1 yr−1. Dry deposition and organic N in wet deposition contributed over half of the input in deposition. Total outputs were 0.4 kg N ha−1 yr−1, the most important outputs being N2O emission to the atmosphere and organic N flux in drainage flow. Nitrogen uptake and retranslocation were as important sources of N for plant growth. Most of the uptaken N originated from decomposition of organic matter, and the fraction of N that could originate directly from deposition was about 30%. In conclusion, atmospheric N deposition fertilizes the site considerably.

scholarly journals Root-Associated Ectomycorrhizal Fungi Shared by Various Boreal Forest Seedlings Naturally Regenerating after a Fire in Interior Alaska and Correlation of Different Fungi with Host Growth Responses

2011 ◽  
Vol 77 (10) ◽  
pp. 3351-3359 ◽  
Author(s):  
Elizabeth Bent ◽  
Preston Kiekel ◽  
Rebecca Brenton ◽  
D. Lee Taylor
Keyword(s):  
Boreal Forest ◽  
Populus Tremuloides ◽  
Fungal Community ◽  
Black Spruce ◽  
Molecular Techniques ◽  
Root Tip ◽  
Small Scale ◽  
Growth Responses ◽  
Root Tips ◽  
Content Type

ABSTRACTThe role of common mycorrhizal networks (CMNs) in postfire boreal forest successional trajectories is unknown. We investigated this issue by sampling a 50-m by 40-m area of naturally regenerating black spruce (Picea mariana), trembling aspen (Populus tremuloides), and paper birch (Betula papyrifera) seedlings at various distances from alder (Alnus viridissubsp.crispa), a nitrogen-fixing shrub, 5 years after wildfire in an Alaskan interior boreal forest. Shoot biomasses and stem diameters of 4-year-old seedlings were recorded, and the fungal community associated with ectomycorrhizal (ECM) root tips from each seedling was profiled using molecular techniques. We found distinct assemblages of fungi associated with alder compared with those associated with the other tree species, making the formation of CMNs between them unlikely. However, among the spruce, aspen, and birch seedlings, there were many shared fungi (including members of thePezoloma ericae[Hymenoscyphus ericae] species aggregate,Thelephora terrestris, andRussulaspp.), raising the possibility that these regenerating seedlings may form interspecies CMNs. Distance between samples did not influence how similar ECM root tip-associated fungal communities were, and of the fungal groups identified, only one of them was more likely to be shared between seedlings that were closer together, suggesting that the majority of fungi surveyed did not have a clumped distribution across the small scale of this study. The presence of some fungal ribotypes was associated with larger or smaller seedlings, suggesting that these fungi may play a role in the promotion or inhibition of seedling growth. The fungal ribotypes associated with larger seedlings were different between spruce, aspen, and birch, suggesting differential impacts of some host-fungus combinations. One may speculate that wildfire-induced shifts in a given soil fungal community could result in variation in the growth response of different plant species after fire and a shift in regenerating vegetation.

scholarly journals Too Much of a Good Thing? Inorganic Nitrogen (N) Inhibits Moss-Associated N2 Fixation But Organic N Can Promote It

2021 ◽  
Author(s):  
Yinliu Wang ◽  
Signe Lett ◽  
Kathrin Rousk
Keyword(s):  
Boreal Forests ◽  
Inorganic Nitrogen ◽  
N Deposition ◽  
Ecosystem Functions ◽  
Organic N ◽  
Inorganic N ◽  
Atmospheric N Deposition ◽  
Moss Species ◽  
The Impact ◽  
N Additions

Abstract Moss-associated nitrogen (N2) fixation is one of the main inputs of new N in pristine ecosystems that receive low amounts of atmospheric N deposition. Previous studies have shown that N2 fixation is inhibited by inorganic N (IN) inputs, but if N2 fixation in mosses is similarly affected by organic N (ON) remains unknown. Here, we assessed N2 fixation in two dominant mosses in boreal forests (Pleurozium schreberi and Sphagnum capillifolium) in response to different levels of N, simulating realistic (up to 4 kg N ha−1 yr−1) and extreme N deposition rates in pristine ecosystems (up to 20 kg N ha−1 yr−1) of IN (NH4NO3) and ON (alanine and urea). We also assessed if N2 fixation can recover from the N additions. In the realistic scenario, N2 fixation was inhibited by increasing NH4NO3 additions in P. schreberi but not in S. capillifolium, and alanine and urea stimulated N2 fixation in both moss species. In contrast, in the extreme N additions, increasing N inputs inhibited N2 fixation in both moss species and all N forms. Nitrogen fixation was more sensitive to N inputs in P. schreberi than in S. capillifolium and was higher in the recovery phase after the realistic compared to the extreme N additions. These results demonstrate that N2 fixation in mosses is less sensitive to organic than inorganic N inputs and highlight the importance of considering different N forms and species-specific responses when estimating the impact of N inputs on ecosystem functions such as moss-associated N2 fixation.

Windthrow hazard modelling in boreal forests of black spruce and jack pine

2005 ◽  
Vol 35 (11) ◽  
pp. 2655-2663 ◽  
Author(s):  
Jean-Gabriel Elie ◽  
Jean-Claude Ruel
Keyword(s):  
Boreal Forests ◽  
Pinus Banksiana ◽  
Forest Cover ◽  
Black Spruce ◽  
Jack Pine ◽  
Soil Conditions ◽  
Mechanical Resistance ◽  
Mixed Stands ◽  
Tree Stability ◽  
Tree Resistance

In this study we compare the mechanical resistance of black spruce (Picea mariana (Mill.) BSP) and jack pine (Pinus banksiana Lamb.) and quantify the effect of species, forest cover type, and soil conditions on tree stability. To measure tree resistance to an applied load, 85 trees were pulled over using a cable and winch system. Predictive equations for the maximum turning moment that a tree can withstand (Mc) were developed with stem mass, and the other factors were used as explanatory variables. The presence of jack pine within the stand negatively affected black spruce resistance. In mixed stands, Mc was significantly influenced by the interaction between tree species and soil type. Jack pine was the only species with significantly lower resistance when grown on shallow and stony soils, which are likely to restrict root development. Black spruce resistance was not affected by soil conditions. Preliminary calculations of critical wind speeds required to cause damage using an adaptation of the ForestGALES model were much lower than those previously published for black spruce.

Structure and resilience of fungal communities in Alaskan boreal forest soilsThis article is one of a selection of papers from The Dynamics of Change in Alaska’s Boreal Forests: Resilience and Vulnerability in Response to Climate Warming.

2010 ◽  
Vol 40 (7) ◽  
pp. 1288-1301 ◽  
Author(s):  
D. Lee Taylor ◽  
Ian C. Herriott ◽  
Kelsie E. Stone ◽  
Jack W. McFarland ◽  
Michael G. Booth ◽  
...  
Keyword(s):  
Mycorrhizal Fungi ◽  
Picea Glauca ◽  
Boreal Forests ◽  
Black Spruce ◽  
Cellulose Degradation ◽  
Niche Partitioning ◽  
Environmental Parameters ◽  
Fungal Species ◽  
Fungal Communities ◽  
Soil Horizon

This paper outlines molecular analyses of soil fungi within the Bonanza Creek Long Term Ecological Research program. We examined community structure in three studies in mixed upland, black spruce ( Picea mariana (Mill.) BSP), and white spruce ( Picea glauca (Moench) Voss) forests and examined taxa involved in cellulose degradation at one upland site. We found that soil horizon was the factor by which fungal communities were most strongly structured and that predictable turnover in upland fungal species occurred through succession. Communities from consecutive summers were not significantly different, indicating that interannual variation was small in relation to differences between forest types and soil horizons, yet the community at a seasonal study site underwent significant changes within a year. In each study, mycorrhizal fungi dominated the community. Fungi rather than bacteria appeared to dominate [13C]cellulose degradation, with strongest growth in taxa that were not dominant members of the untreated community, including members of the genus Sebacina . Overall, our results point to considerable interannual resilience juxtaposed with narrow niche partitioning and the capacity of individual taxa in these hyperdiverse communities to respond strongly to resource inputs and changes in other abiotic environmental parameters such as temperature. Our data double the cumulative total of fungal sequences in GenBank and together achieve a better picture of fungal communities here than for any other ecosystem on earth at this time.

Effects of Fertilization and Irrigation on Root Numbers in a Red Pine Plantation

1974 ◽  
Vol 4 (3) ◽  
pp. 366-371 ◽  
Author(s):  
Edward P. Farrell ◽  
Albert L. Leaf
Keyword(s):  
New York ◽  
Sampling Error ◽  
Morphological Characteristics ◽  
Sampling Technique ◽  
Red Pine ◽  
Root Tip ◽  
Soil Conditions ◽  
Soil Cores ◽  
Root Tips ◽  
Root Numbers

A core sampling technique was used for the investigation of root numbers in a 42-year-old red pine (Pinusresinosa Ait.) irrigation – K fertilization experimental area of a K deficient sandy outwash plain in the southeastern Adirondack Mountain Region of New York. Soil cores were collected from plots, 6 years after initiation of treatments, at 0–15 and 15–30 cm depths, using a 5.2 cm diameter corer. Roots were separated from soil cores by a sieving technique. Root tips, including each tip of mycorrhizal structures, were counted by classes established on the basis of morphological characteristics. Numbers of root tips were greater under nonfertilized than fertilized plots, and greater under irrigated than nonirrigated plots. This response pattern did not follow that of wood volume increment, which was greatest in fertilized plots, but was similar to the previously reported pattern in soil microarthropod numbers. The great natural variation observed suggests that root tip numbers may be highly sensitive to changes in soil conditions. Calculated sampling intensity, based on the variance estimates, and specific levels of probabilities (α and β) and allowable sampling error (ε), indicated the need for high numbers of samples.

scholarly journals Ectomycorrhizal Colonisation in Declining Oak Stands on the Krotoszyn Plateau, Poland

Forests ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 30 ◽  
Author(s):  
Roman Mariusz Bzdyk ◽  
Jacek Olchowik ◽  
Marcin Studnicki ◽  
Justyna Anna Nowakowska ◽  
Tomasz Oszako ◽  
...  
Keyword(s):  
Fungal Species ◽  
Root Tip ◽  
Root Tips ◽  
Long Distance ◽  
Particle Size Fractions ◽  
Root Parameters ◽  
Exploration Types ◽  
Forest Sites ◽  
Fine Grained Soil ◽  
Crown Health

We describe the ectomycorrhizal (ECM) root tips and the diversity of mycorrhizal fungal species at three English oak (Quercus robur) sites (two 120 year old sites and one 60 year old site). The three oak stands in decline, located in western Poland, were characterized by a low degree of vital ECM colonization: 30.2%, 29.1% and 25.6% at Krotoszyn (K), Piaski (P) and Karczma Borowa (KB), respectively. DNA (ITS) barcoding revealed a total of 18 ECM fungal species. Based on exploration types, ectomycorrhizae were classified with respect to ecologically relevant features. The contact type was significantly correlated with C:N and Corg, while the short distance type was correlated with Ca, phosphorus (P2O5) and pH. The medium distance exploration type was significantly correlated with fine-grained soil particle size fractions: coarse silt (0.05–0.02 mm) and fine silt (0.02–0.002 mm), and clay (<0.002 mm). The long distance type showed a similar pattern to the medium distance smooth type, but was also correlated with nitrate (N). The values of biometric root parameters of oak trees at the analysed forest sites were arranged as follows: K > P > KB, and were opposite to the condition of the tree crowns. A negative correlation of vital ECM root tip abundance with the crown health status of oaks was observed, whereas higher ECM diversity reflected better crown health in the oak stands studied.

scholarly journals Ectomycorrhizal Fungal Associates of Pinus contorta in Soils Associated with a Hot Spring in Norris Geyser Basin, Yellowstone National Park, Wyoming

2001 ◽  
Vol 67 (12) ◽  
pp. 5538-5543 ◽  
Author(s):  
Ken Cullings ◽  
Shilpa Makhija
Keyword(s):  
Forest Soil ◽  
Forest Soils ◽  
Pinus Contorta ◽  
Dominant Species ◽  
Hot Spring ◽  
Acid Soils ◽  
Fungal Species ◽  
Root Tip ◽  
Fruiting Bodies ◽  
Root Tips

ABSTRACT Molecular methods and comparisons of fruiting patterns (i.e., presence or absence of fungal fruiting bodies in different soil types) were used to determine ectomycorrhizal (EM) associates of Pinus contorta in soils associated with a thermal soil classified as ultra-acidic to extremely acidic (pH 2 to 4). EM were sampled by obtaining 36 soil cores from six paired plots (three cores each) of both thermal soils and forest soils directly adjacent to the thermal area. Fruiting bodies (mushrooms) were collected for molecular identification and to compare fruiting body (above-ground) diversity to below-ground diversity. Our results indicate (i) that there were significant decreases in both the level of EM infection (130 ± 22 EM root tips/core in forest soil; 68 ± 22 EM root tips/core in thermal soil) and EM fungal species richness (4.0 ± 0.5 species/core in forest soil; 1.2 ± 0.2 species/core in thermal soil) in soils associated with the thermal feature; (ii) that the EM mycota of thermal soils was comprised of a small set of dominant species and included very few rare species, while the EM mycota of forest soils contained a few dominant species and several rare EM fungal species; (iii) that Dermocybe phoenecius and a species of Inocybe, which was rare in forest soils, were the dominant EM fungal species in thermal soils; (iv) that other than the single Inocybe species, there was no overlap in the EM fungal communities of the forest and thermal soils; and (v) that the fungal species forming the majority of the above-ground fruiting structures in thermal soils (Pisolithus tinctorius, which is commonly used in remediation of acid soils) was not detected on a single EM root tip in either type of soil. Thus, P. tinctorius may have a different role in these thermal soils. Our results suggest that this species may not perform well in remediation of all acid soils and that factors such as pH, soil temperature, and soil chemistry may interact to influence EM fungal community structure. In addition, we identified at least one new species with potential for use in remediation of hot acidic soil.

scholarly journals Nitrogen balance of a boreal Scots pine forest

2013 ◽  
Vol 10 (2) ◽  
pp. 1083-1095 ◽  
Author(s):  
J. F. J. Korhonen ◽  
M. Pihlatie ◽  
J. Pumpanen ◽  
H. Aaltonen ◽  
P. Hari ◽  
...  
Keyword(s):  
Scots Pine ◽  
Boreal Forests ◽  
N2o Emission ◽  
N Deposition ◽  
Organic N ◽  
N Availability ◽  
N Saturation ◽  
Atmospheric N Deposition ◽  
Drainage Flow ◽  
Nutrient Pools

Abstract. The productivity of boreal forests is considered to be limited by low nitrogen (N) availability. Increased atmospheric N deposition has altered the functioning and N cycling of these N-sensitive ecosystems by increasing the availability of reactive nitrogen. The most important components of N pools and fluxes were measured in a boreal Scots pine stand in Hyytiälä, Southern Finland. The measurements at the site allowed direct estimations of nutrient pools in the soil and biomass, inputs from the atmosphere and outputs as drainage flow and gaseous losses from two micro-catchments. N was accumulating in the system, mainly in woody biomass, at a rate of 7 kg N ha−1 yr−1. Nitrogen input as atmospheric deposition was 7.4 kg N ha−1 yr−1. Dry deposition and organic N in wet deposition contributed over half of the inputs in deposition. Total outputs were 0.4 kg N ha−1 yr−1, the most important outputs being N2O emission to the atmosphere and organic N flux in drainage flow. Nitrogen uptake and retranslocation were equally important sources of N for plant growth. Most of the assimilated N originated from decomposition of organic matter, and the fraction of N that could originate directly from deposition was about 30%. In conclusion, atmospheric N deposition fertilizes the site considerably, but there are no signs of N saturation. Further research is needed to estimate soil N2 fluxes (emission and fixation), which may amount up to several kg N ha−1 yr−1.

Root Tip Growth and the Presence of Leaves Affect Epicormic and Lignotuberous Shoot Development and Survival of Stressed Eucalyptus obliqua L’Herit. Seedlings

2021 ◽  
Vol 47 (4) ◽  
pp. 133-149
Author(s):  
G.M. Moore
Keyword(s):  
Shoot Growth ◽  
Tip Growth ◽  
Survival Rates ◽  
Root Tip ◽  
Soil Conditions ◽  
Plant Responses ◽  
Root Tips ◽  
Shoot Production ◽  
The Relationship ◽  
Different Levels

The shoots produced from axillary, epicormic, and lignotuberous buds are significant parts of stress recovery responses in many tree species. The production of either epicormic or lignotuberous shoots does not guarantee survival of a tree, as the mortality of shoots is high. This research investigated the relationship between root tip growth and shoot production and survival after stress and its implications for urban tree managers. Seedlings of Eucalyptus obliqua L’Herit. were stressed by decapitation or different levels of heat stress at temperatures ranging from 40 °C to 100 °C for 2 to 128 minutes, as well as combinations of the two stresses. While the temperatures are not as high as those experienced in a forest fire, the stresses imposed can inform plant responses to stress such as fire. Lower temperatures and shorter durations were often sublethal, and decapitation, to the same extent as heat killing of plant tissues, elicited similar levels of epicormic and lignotuberous shoot growth. The root systems of the seedlings were inspected to determine whether the root tips were healthy, and selected root tips were monitored to determine if and when they had resumed growth. Survival rates of epicormic and lignotuberous shoots were enhanced by the presence of healthy leaves. The recommencement of growth after stress by the development of epicormic or lignotuberous shoots was preceded by root tip growth, which emphasises the importance of a healthy root system. Managing for the best soil conditions possible during and immediately after stress may be a key to successful shoot production and tree recovery.

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