scholarly journals Gap Size in Hyrcanian Forest Affects the Lignin and N Concentrations of the Oriental Beech (Fagus orientalis Lipsky) Fine Roots but Does Not Change Their Morphological Traits in the Medium Term

Forests ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 137
Author(s):  
Alireza Amoli Kondori ◽  
Kambiz Abrari Vajari ◽  
Mohammad Feizian ◽  
Antonio Montagnoli ◽  
Antonino Di Iorio

Research Highlights: Fine roots play an important role in plant growth as well as in carbon (C) and nutrient cycling in terrestrial ecosystems. Gaining a wider knowledge of their dynamics under forest gap opening would improve our understanding of soil carbon input and below-ground carbon stock accumulation. Single-tree selection is increasingly recognized as an alternative regime of selection cutting sustaining biodiversity and carbon stock, along with timber production, among ecosystem functions. However, the fine root response in terms of morphological and chemical composition to the resulting harvest-created gaps remains unclear. Background and Objectives: This paper investigates the effect in the medium term (i.e., 6 years after logging) of differently sized harvest-created gaps on fine root dynamics and chemical composition. Materials and Methods: A total of 15 differently sized gaps (86.05–350.7 m2) and the adjacent 20 m distant closed canopies (control) were selected in a temperate Fagus orientalis forest (Hyrcanian region, Iran). Eight soil cores were collected at the cardinal points of the gap edge, including four facing the gap area—the same at the adjacent intact forest. Results: For the selected edge trees, the different size of gaps, the core position, and the tree orientation did not affect the investigated morphological traits, except for the slightly higher specific root length (SRL) for the larger fine root fraction (1–2 mm) in the side facing the gap area. Differently, the investigated chemical traits such as N concentration and cellulose:lignin ratio significantly increased with increasing gap size, the opposite for C:N ratio and lignin. Moreover, N concentration and C:N significantly decreased and increased with the fine root diameter, respectively. Conclusions: This work highlighted that, in the medium term and within the adopted size range, artificial gap opening derived from single-tree selection practice affected the chemistry rather than the biomass and morphology of gap-facing fine roots of edge trees. The medium term of six years after gap creation might have been long enough for the recovery of the fine root standing biomass to the pre-harvest condition, particularly near the stem of edge trees. A clear size threshold did not come out; nevertheless, 300 m2 may be considered a possible cut-off determining a marked change in the responses of fine roots.

2021 ◽  
Author(s):  
Romain Jaeger ◽  
Sylvain Delagrange ◽  
Isabelle Aubin ◽  
Gilles Joanisse ◽  
Patricia Raymond ◽  
...  

Abstract Background: Short-term effects of silvicultural treatments on soil properties and understory vegetation in temperate hardwood forests are well documented, but few studies have examined longer term effects of treatment intensity. We hypothesized that short-term effects of silvicultural treatments on understory plant diversity do persist over the medium-term (20 years after treatment); the magnitude of these effects would be proportional to the intensity of canopy and soil disturbance.Methods: Soil properties (pH, total C and N, extractable P, exchangeable bases) and understory community diversity indices were measured in six experimental sites along a longitudinal gradient that covered different climatic and edaphic conditions in the yellow birch-sugar maple bioclimate domain. Reference condition, i.e. control forest with no anthropogenic disturbance for at least 80 years (CON) were compared to twenty years old regeneration treaments representing a gradient of canopy and soil disturbance intensity: single-tree selection cuts (SIN); group-selection cuts (GRP); and group-selection cuts with scarification (GRPS). Results: Geographic location of sites explained more variation in soil properties and community composition than did treatments. Species richness in both group-selection treatments was higher than that in CON forests. However, understory plant equitability and beta diversity among sites in GRP and GRPS were lower than in SIN and CON forests. More intense treatments (GRP and GRPS) increased the relative occurrence of vegetatively reproducing heliophilic plants, a trait syndrome associated with adaptations to disturbed environments. These treatments also contributed to the medium-term persistence of recalcitrant competitor species (e.g., Rubus idaeus, Prunus pensylvanica) whereas soil scarification appears to have negative sustained effects on species known to be sensitive to regeneration treatments (e.g. Monotropa uniflora, Dryopteris spinulosa).Conclusion: Of the treatments studied, single-tree selection cutting appears to be the most appropriate silvicultural treatment for maintaining soil functions and heterogeneous understory plant communities with compositions and structures similar to natural forests, while more intense treatments rather maintain and expand species that are better adapted to a wider range of environmental conditions, including open environments.


HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 511a-511
Author(s):  
L.H. Comas ◽  
D.M. Eissenstat ◽  
A.N. Lakso ◽  
R. Dunst

Improved cultural practices in grape require a better understanding of root growth and physiology. Seasonal root dynamics were examined in mature `Concord' vines with balanced or minimal-pruning, and with or without supplemental irrigation in Fredonia, N.Y. Fine roots were continuously produced during the growing season starting in mid-June around time of bloom. Roots began to die in September at verasion. Minimal-pruned vines produced more roots than balanced-pruned vines, with the minimal-pruned/unirrigated vines producing the most roots. Irrigation and pruning delayed fine root production at the beginning of the growing season. Peak fine root flush was 16 June to 21 July 1997 for the minimal-pruned/unirrigated treatment, while peak flush was 7 July to 2 Sept. 1997 for balanced-pruned/irrigated treatment. In minimal-pruned vines, many roots were observed down to depths of 120 cm. In contrast, balanced-pruned vines had very few fine roots deeper than 40 cm. From initial observations, median lifespan of fine roots was 5 to 9.5 weeks, depending on treatment and depth in soil. Fine roots lived longer in the top 15-cm than in the 16- to 30-cm layer of soil in all treatments. Both minimal pruning and irrigation increased root lifespan. Fine roots had the shortest lifespan in the balanced-pruned/unirrigated treatment and the longest lifespan in the minimal-pruned/irrigated treatment.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
G. Grunewaldt-Stöcker ◽  
C. Popp ◽  
A. Baumann ◽  
S. Fricke ◽  
M. Menssen ◽  
...  

AbstractReplant disease is a worldwide phenomenon affecting various woody plant genera and species, especially within the Rosaceae. Compared to decades of intensive studies regarding replant disease of apple (ARD), the replant disease of roses (RRD) has hardly been investigated. The etiology of RRD is also still unclear and a remedy desperately needed. In greenhouse pot trials with seedlings of the RRD-sensitive rootstock Rosa corymbifera ‘Laxa’ cultured in replant disease affected soils from two different locations, early RRD symptom development was studied in fine roots. In microscopic analyses we found similarities to ARD symptoms with regards to structural damages, impairment in the root hair status, and necroses and blackening in the cortex tissue. Examinations of both whole mounts and thin sections of fine root segments revealed frequent conspicuous fungal infections in association with the cellular disorders. Particularly striking were fungal intracellular structures with pathogenic characteristics that are described for the first time. Isolated fungi from these tissue areas were identified by means of ITS primers, and many of them were members of the Nectriaceae. In a next step, 35 of these isolates were subjected to a multi-locus sequence analysis and the results revealed that several genera and species were involved in the development of RRD within a single rose plant. Inoculations with selected single isolates (Rugonectria rugulosa and Ilyonectria robusta) in a Perlite assay confirmed their pathogenic relationship to early necrotic host plant reactions, and symptoms were similar to those exhibited in ARD.


2020 ◽  
Author(s):  
Alexander C Helman ◽  
Matthew C Kelly ◽  
Mark D Rouleau ◽  
Yvette L Dickinson

Abstract Managing northern hardwood forests using high-frequency, low-intensity regimes, such as single-tree selection, favors shade-tolerant species and can reduce tree species diversity. Management decisions among family forest owners (FFO) can collectively affect species and structural diversity within northern hardwood forests at regional scales. We surveyed FFOs in the Western Upper Peninsula of Michigan to understand likely future use of three silvicultural treatments—single-tree selection, shelterwood, and clearcut. Our results indicate that FFOs were most likely to implement single-tree selection and least likely to implement clearcut within the next 10 years. According to logistic regression, prior use of a treatment and perceived financial benefits significantly increased the odds for likely use for all three treatments. Having received professional forestry assistance increased likely use of single-tree selection but decreased likely use of shelterwood. We discuss these results within the context of species diversity among northern hardwood forests throughout the region.


1992 ◽  
Vol 22 (11) ◽  
pp. 1575-1582 ◽  
Author(s):  
Adrián Ares ◽  
Norman Peinemann

A study was conducted to determine the amounts and vertical distribution of fine roots <2 mm as a function of site quality in a temperate, hilly zone of Argentina. Fine roots were sampled in autumn from 0.2-ha plots established in 12 coniferous plantations of Pinushalepensis Mill., Pinusradiata D. Don, Cedrusdeodara (D. Don) G. Don, and Cupressussempervirens L.f. horizontalis, located in Sierra de la Ventana, southern Buenos Aires. Generally, root density was found to be higher under low-growth stands. The distance from a tree sometimes had an effect on root density, but no clear pattern within stands could be observed. Root density commonly decreased with depth, but slight irregularities in some profiles were observed. Site quality and soil type influenced root distribution. Belowground biomass up to a depth of 50 cm ranged from 1600 to 9800 kg•ha−1 in high-growth stands and from 5400 to 40 700 kg•ha−1 in low-growth stands. Soil organic matter content provided the best correlation with root density. A possible practical implication would be the use of indices related to vertical distribution of organic matter, among other variables, as complementary estimators of effective depth of rooting. The results strongly suggest that trees maintain a large fine-root system in poor sites at the expense of aboveground growth.


2004 ◽  
Vol 34 (5) ◽  
pp. 985-997 ◽  
Author(s):  
Thomas M Schuler

Long-term silvicultural trials contribute to sustainable forest management by providing a better scientific understanding of how forest ecosystems respond to periodic timber harvesting. In this study, species composition, diversity, and net periodic growth of tree species in a mixed mesophytic forest in the central Appalachians were evaluated after about a half century of management. Three partial cutting practices on 18 research compartments and on 3 unmanaged reference compartments were evaluated (1951–2001) on 280 ha. Single-tree selection, diameter-limit harvesting, and timber harvesting in 0.162-ha patches were assessed on three northern red oak site index50 (SI) classes: 24, 21, and 18. Shannon–Weiner's diversity index (H′) declined from the first (1951–1959) to last (1987–2001) measurements and was related to both SI (P = 0.004) and treatment (P = 0.009). Sugar maple (Acer saccharum Marsh.) and red maple (Acer rubrum L.) were the two most abundant species in recent years (1987–2001); in contrast, in initial inventories (1951–1959), northern red oak (Quercus rubra L.) and chestnut oak (Quercus prinus L.) were most abundant. Net periodic annual increment (PAI) of merchantable trees (DBH ≥12.7 cm) was related to both SI (P = 0.004) and treatment (P = 0.003). Mean PAI ranged from 4.6 m3·ha–1·year–1 for single-tree selection to 2.5 m3·ha–1·year–1 for unmanaged reference areas across all SI classes. The decline of oak species suggests that only intensive and specific forest management focused on maintaining oak species can obtain historical levels of diversity.


2021 ◽  
Author(s):  
Marili Sell ◽  
Ivika Ostonen ◽  
Gristin Rohula-Okunev ◽  
Linda Rusalepp ◽  
Azadeh Rezapour ◽  
...  

Abstract Global climate change scenarios predict an increase in air temperature, precipitation, and air humidity for northern latitudes. Elevated air humidity may significantly reduce the water flux through forest canopies and affect interactions between water and nutrient uptake. However, we have limited understanding of how altered transpiration would affect root respiration and carbon (C) exudation as fine root morphology acclimates to different water flux. We investigated the effects of elevated air relative humidity (eRH) and different inorganic nitrogen sources (NO3− and NH4+) on above and belowground traits in hybrid aspen (Populus × wettsteinii Hämet-Ahti), silver birch (Betula pendula Roth.), and Scots pine (Pinus sylvestris L.) grown under controlled climate chamber conditions. The eRH significantly decreased the transpiration flux in all species, decreased root mass-specific exudation in pine, and increased root respiration in aspen. eRH also affected fine root morphology, with specific root area increasing for birch but decreasing in pine. The species comparison revealed that pine had the highest C exudation, while birch had the highest root respiration rate. Both humidity and nitrogen treatments affected the share of absorptive and pioneer roots within fine roots; however, the response was species-specific. The proportion of absorptive roots was highest in birch and aspen, the share of pioneer roots was greatest in aspen, and the share of transport roots was greatest in pine. Fine roots with lower root tissue density were associated with pioneer root tips and had a higher C exudation rate. Our findings underline the importance of considering species-specific differences in relation to air humidity and soil nitrogen availability that interactively affect the C input–output balance. We highlight the role of changes in the fine root functional distribution as an important acclimation mechanism of trees in response to environmental change.


1998 ◽  
Vol 78 (1) ◽  
pp. 163-169 ◽  
Author(s):  
J. S. Bhatti ◽  
N. W. Foster ◽  
P. W. Hazlett

Vertical distribution of fine root biomass and nutrient content was examined within a black spruce (Picea mariana) stand growing on a boreal peat soil in northeastern Ontario. The influence of site physical and chemical properties on fine root biomass production was assessed. More then 80% of the fine roots were present in moss plus the top 10 cm of peat where nutrients and aeration are most favourable. The fine root biomass (W/V) was significantly higher with alder (5.9 kg m−3) (Alnus rugosa) as understory vegetation compared to non-alder locations (2.9 kg m−3). Total nutrient content in fine roots was 54, 3.2, 5.4, 63 and 5.7 kg ha−1 on the alder site and 20, 1.4, 2.3, 28 and 4.2 kg ha−1 of N, P, K, Ca, and Mg on the non-alder site, respectively. The mass (W/V) of nutrients in fine roots was strongly dependent upon the availability of nutrients in the peat. Fine root content had a strong positive relationship with peat available P and exchangeable K contents suggesting that P and K may be limiting nutrients for black spruce in this peat soil. Key words: Nitrogen, phosphorus, potassium, boreal peatlands, aeration, water table


2009 ◽  
Vol 27 (4) ◽  
pp. 229-233 ◽  
Author(s):  
Gary W. Watson

Abstract Exposed fine roots are subject to desiccation, which may affect their survival as well as new root growth following bare root transplanting. Fine roots of dormant 1-year-old green ash (Fraxinus pennsylvanica) and sugar maple (Acer saccharum) seedlings, subjected to desiccation treatments of 0, 1, 2, or 3 hours in December and March, lost up to 82 percent of their water. Root electrolyte leakage, a measure of cell damage, tripled after three hours of desiccation. The increase was moderately, but significantly, greater in March for both species. Desiccation treatments had no effect on fine root survival. Growth of new roots (RGP) was also unaffected by desiccation treatments. RGP of maple was greater in March than December, but not ash.


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