Drought and Nitrogen Application Modulate the Morphological and Physiological Responses of Dalbergia odorifera to Different Niche Neighbors

Mixed stands can be more productive if growth facilitation via niche segregation occurs. Dalbergia odorifera T. Chen, a tropical tree species endemic to Hainan Island with great economic values, belongs to the family Leguminosae. However, selecting mixed species with suitable ecological niches to efficiently construct mixed forests of D. odorifera in the context of abiotic stress [drought, nitrogen (N) deposition] remained obscure. In the present study, the target plant D. odorifera was planted with the same species D. odorifera, heterogeneous but the same family Delonix regia and non-Leguminous Family Swietenia mahagoni in the root interaction and isolated models under two watering regimes [100% and 30% field capacity (FC)] and two N applications (application, non-application), respectively. Principle component analysis based on the performances of growth, phenotype, and physiology was performed to identify the main factors affected by the treatments and the most discriminatory effects of water, N level, and species interaction models. Both comprehensive evaluation values and comprehensive index values were calculated to evaluate the influences of different niche neighbors on D. odorifera. Results showed that D. odorifera was benefited from S. mahagoni but inhibited from D. odorifera in all treatments under root system interaction. Drought stress aggravated the inhibitory effects on D. odorifera from D. odorifera. N application stimulated the promoted effects on D. odorifera from S. mahagoni but enhanced competition intensity of D. odorifera from D. regia under the 100% FC condition. N application alleviated the inhibitory effect of drought stress on D. odorifera from D. odorifera and S. mahagoni. Furthermore, the responses of D. odorifera to different niche neighbors were dominated by belowground interaction rather than the negligible aboveground one. Therefore, the feasibility of niche segregation as the criterion for selecting neighbors to construct D. odorifera mixed stands was confirmed. In addition, water level and N application could alter responses of D. odorifera to different niche neighbors under the root system interaction. Appropriate N application could alleviate the inhibitory effect of drought stress on D. odorifera in its mixed forests. A mixture with S. mahagoni under appropriate N application could be the optimal planting model.

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Neighbors, Drought, and Nitrogen Application Affect the Root Morphological Plasticity of Dalbergia odorifera

Frontiers in Plant Science ◽

10.3389/fpls.2021.650616 ◽

2021 ◽

Vol 12 ◽

Author(s):

Li-Shan Xiang ◽

Ling-Feng Miao ◽

Fan Yang

Keyword(s):

Root System ◽

Root Morphology ◽

Relative Yield ◽

Morphological Plasticity ◽

Promoting Effect ◽

N Application ◽

Growth Ratio ◽

N Deficiency ◽

Dalbergia Odorifera ◽

Root Morphological Plasticity

In forest systems, neighbor-induced root morphological plasticity (RMP) is species specific and environment dependent. However, related studies on leguminous woody trees remain sparse. The objectives of this study were to evaluate the root morphological response of the leguminous woody Dalbergia odorifera T. Chen to different N-fixing niche neighbors under models of root system contact and isolation and to evaluate whether such response can be modified by drought or the application of nitrogen (N). The relationship between root morphology and the relative competitiveness of the whole D. odorifera plantlet was also assessed. D. odorifera plantlets from the woody Leguminosae family were used as target species and were grown with either identical N-fixing niche D. odorifera, the heterogeneous but con-leguminous Delonix regia, or the non-leguminous Swietenia mahagoni. All plants were grown under two water conditions (100% and 30% field capacity) and two N treatments (no N application and N application). Two planting models (root system contact in Experiment 1, root system isolation in Experiment 2) were applied to neighboring plantlets. The RMP of D. odorifera was assessed based on root morphology, root system classification, root nodules, and RMP-related indices. The growth of D. odorifera was estimated based on the relative growth ratio, net assimilation rate, and leaf N content. The relative competitiveness of the whole D. odorifera plantlet was evaluated through relative yield. The results of Experiment 1 showed that D. odorifera had different RMP responses to a different N-fixing niche neighbor with root system contact. The RMP of D. odorifera was promoted by a different N-fixing niche neighbor under conditions of drought or N deficiency. Drought improved the RMP of D. odorifera exposed to a different N-fixing niche neighbor. N application converted the promoting effect of D. regia on RMP to an inhibitory effect under well-watered conditions. Experiment 2 showed that belowground interaction with a different N-fixing niche neighbor may be the only way to influence RMP, as effects of aboveground interaction were negligible. Finally, correlation analysis showed that neighbor-induced RMP might predict the relative competitiveness of the whole D. odorifera plantlet under conditions of drought or N deficiency. These findings highlight the influences of neighbors, drought, and N application on the RMP of D. odorifera and contribute to understanding neighbor-induced dynamic changes in the root traits of leguminous woody species in forest systems in the context of climate change.

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Distribution of the timber quality attribute ‘knot surface’ in logs of Fagus sylvatica L. from pure and mixed forest stands

European Journal of Forest Research ◽

10.1007/s10342-021-01378-9 ◽

2021 ◽

Author(s):

Kirsten Höwler ◽

Torsten Vor ◽

Peter Schall ◽

Peter Annighöfer ◽

Dominik Seidel ◽

...

Keyword(s):

Fagus Sylvatica ◽

Mixed Forest ◽

European Beech ◽

Forest Stands ◽

Species Identity ◽

Mixed Stands ◽

Mixed Forests ◽

Climate Conditions ◽

Timber Quality ◽

Positive Effects

AbstractResearch on mixed forests has mostly focused on tree growth and productivity, or resistance and resilience in changing climate conditions, but only rarely on the effects of tree species mixing on timber quality. In particular, it is still unclear whether the numerous positive effects of mixed forests on productivity and stability come at the expense of timber quality. In this study, we used photographs of sawn boards from 90 European beech (Fagus sylvatica L.) trees of mixed and pure forest stands to analyze internal timber quality through the quality indicator knot surface that was quantitatively assessed using the software Datinf® Measure. We observed a decrease in knot surface with increasing distance from the pith as well as smaller values in the lower log sections. Regarding the influence of neighborhood species identity, we found only minor effects meaning that timber qualities in mixed stands of beech and Norway spruce (Picea abies (L.) H. Karst.) tended to be slightly worse compared to pure beech stands.

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Object Oriented Classification for Mapping Mixed and Pure Forest Stands Using Very-High Resolution Imagery

Remote Sensing ◽

10.3390/rs13132508 ◽

2021 ◽

Vol 13 (13) ◽

pp. 2508

Author(s):

Loredana Oreti ◽

Diego Giuliarelli ◽

Antonio Tomao ◽

Anna Barbati

Keyword(s):

High Resolution ◽

Spatial Scales ◽

Parametric Method ◽

Mixed Forest ◽

Mixed Stands ◽

Mapping Unit ◽

Mixed Forests ◽

High Resolution Imagery ◽

Very High Resolution Imagery ◽

Very High

The importance of mixed forests is increasingly recognized on a scientific level, due to their greater productivity and efficiency in resource use, compared to pure stands. However, a reliable quantification of the actual spatial extent of mixed stands on a fine spatial scale is still lacking. Indeed, classification and mapping of mixed populations, especially with semi-automatic procedures, has been a challenging issue up to date. The main objective of this study is to evaluate the potential of Object-Based Image Analysis (OBIA) and Very-High-Resolution imagery (VHR) to detect and map mixed forests of broadleaves and coniferous trees with a Minimum Mapping Unit (MMU) of 500 m2. This study evaluates segmentation-based classification paired with non-parametric method K- nearest-neighbors (K-NN), trained with a dataset independent from the validation one. The forest area mapped as mixed forest canopies in the study area amounts to 11%, with an overall accuracy being equal to 85% and K of 0.78. Better levels of user and producer accuracies (85–93%) are reached in conifer and broadleaved dominated stands. The study findings demonstrate that the very high resolution images (0.20 m of spatial resolutions) can be reliably used to detect the fine-grained pattern of rare mixed forests, thus supporting the monitoring and management of forest resources also on fine spatial scales.

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A contribution to the sessile oak site and beech site defining in central Serbia

Glasnik Sumarskog fakulteta ◽

10.2298/gsf0900143k ◽

2009 ◽

pp. 143-158

Author(s):

Milun Krstic ◽

Bojana Cevrljakovic

Keyword(s):

Tree Species ◽

Local Heat ◽

Mixed Stands ◽

Mixed Forests ◽

Altitudinal Belt ◽

Sessile Oak ◽

Heat Potential ◽

Tree Number ◽

Broadleaf Species ◽

Weighted Values

The study was carried out in sessile oak forests and beech forests in the region central Serbia. The stands are classified as pure stands with the percentage of other species up to 10% per tree number, mixed forests of sessile oak with other species, and mixed forests of beech with other species, whose percentage does not exceed 50%. Altogether 257 stands were monitored - 202 beech stands and 55 sessile oak stands. By the applied method of defining the local heat potential (Lujic, 1960), modified by Ratknic et al. (2001) and Krstic (2004, 2008), which represents possibility of soil heating without vegetation, were determined. In this way, a scale of 162 possible combinations of local heat potential was obtained, which explains more precisely the dependence of beech stands and sessile oak stands on the topographic conditions. By applying the weighted values of the thermal co-ordinates of aspect and slope (E) for each altitudinal belt of 100 m, it was concluded that pure stands have the widest ecological range. Pure beech stands occur at the sites with 34 combinations of thermal co-ordinates E.V=4.6 to 8.12. Pure sessile oak stands occur at the sites with 12 combinations of thermal co-ordinates E.V=5.10 to 8.11. The percentage of mixed beech stands with other broadleaf species is the highest at the sites with the co-ordinate V=10-11 (at the altitudes between 700 and 900 m) is about 60 %. Mixed stands of sessile oak and beech are located on the terrains with combinations of thermal co-ordinates E.V=7.9 to 8.12. By using the local heat potential of a region, it can be identified which sites, i.e. which combinations of exposure, slope and altitude belong to the particular tree species. Consequently, a more reliable selection of tree species can be done for the bio-reclamation of barrens and other deforested terrains.

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The Impact of Drought in Plant Metabolism: How to Exploit Tolerance Mechanisms to Increase Crop Production

Applied Sciences ◽

10.3390/app10165692 ◽

2020 ◽

Vol 10 (16) ◽

pp. 5692 ◽

Cited By ~ 4

Author(s):

Dhriti Kapoor ◽

Savita Bhardwaj ◽

Marco Landi ◽

Arti Sharma ◽

Muthusamy Ramakrishnan ◽

...

Keyword(s):

Climate Change ◽

Drought Stress ◽

Water Availability ◽

Arable Land ◽

Ecological Niches ◽

Antioxidant Systems ◽

Crop Species ◽

Change Factors ◽

The Impact ◽

Stimulation Of

Plants are often exposed to unfavorable environmental conditions, for instance abiotic stresses, which dramatically alter distribution of plant species among ecological niches and limit the yields of crop species. Among these, drought stress is one of the most impacting factors which alter seriously the plant physiology, finally leading to the decline of the crop productivity. Drought stress causes in plants a set of morpho-anatomical, physiological and biochemical changes, mainly addressed to limit the loss of water by transpiration with the attempt to increase the plant water use efficiency. The stomata closure, one of the first consistent reactions observed under drought, results in a series of consequent physiological/biochemical adjustments aimed at balancing the photosynthetic process as well as at enhancing the plant defense barriers against drought-promoted stress (e.g., stimulation of antioxidant systems, accumulation of osmolytes and stimulation of aquaporin synthesis), all representing an attempt by the plant to overcome the unfavorable period of limited water availability. In view of the severe changes in water availability imposed by climate change factors and considering the increasing human population, it is therefore of outmost importance to highlight: (i) how plants react to drought; (ii) the mechanisms of tolerance exhibited by some species/cultivars; and (iii) the techniques aimed at increasing the tolerance of crop species against limited water availability. All these aspects are necessary to respond to the continuously increasing demand for food, which unfortunately parallels the loss of arable land due to changes in rainfall dynamics and prolonged period of drought provoked by climate change factors. This review summarizes the most updated findings on the impact of drought stress on plant morphological, biochemical and physiological features and highlights plant mechanisms of tolerance which could be exploited to increase the plant capability to survive under limited water availability. In addition, possible applicative strategies to help the plant in counteracting unfavorable drought periods are also discussed.

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Inoculation with arbuscular mycorrhizal fungi enhances the root system of Bauhinia faberi var. microphylla seedlings under drought stress conditions

Acta Ecologica Sinica ◽

10.5846/stxb201601280209 ◽

2017 ◽

Vol 37 (8) ◽

Cited By ~ 1

Author(s):

张亚敏 ZHANG Yamin ◽

马克明 MA Keming ◽

曲来叶 QU Laiye

Keyword(s):

Drought Stress ◽

Arbuscular Mycorrhizal Fungi ◽

Root System ◽

Mycorrhizal Fungi ◽

Arbuscular Mycorrhizal ◽

Stress Conditions

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Drought Stress Reaction of Growth and Δ13C in Tree Rings of European Beech and Norway Spruce in Monospecific Versus Mixed Stands Along a Precipitation Gradient

Forests ◽

10.3390/f8060177 ◽

2017 ◽

Vol 8 (6) ◽

pp. 177 ◽

Cited By ~ 15

Author(s):

Cynthia Schäfer ◽

Thorsten Grams ◽

Thomas Rötzer ◽

Aline Feldermann ◽

Hans Pretzsch

Keyword(s):

Drought Stress ◽

Norway Spruce ◽

Tree Rings ◽

European Beech ◽

Stress Reaction ◽

Precipitation Gradient ◽

Mixed Stands

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Root system response in Argania spinosa plants under drought stress and recovery

Plant Signaling & Behavior ◽

10.1080/15592324.2018.1489669 ◽

2018 ◽

Vol 13 (7) ◽

pp. e1489669 ◽

Cited By ~ 1

Author(s):

A. Chakhchar ◽

N. Chaguer ◽

A. Ferradous ◽

A. Filali-Maltouf ◽

C. El Modafar

Keyword(s):

Drought Stress ◽

Root System ◽

System Response ◽

Argania Spinosa

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Application of the BDq method to complex tropical mixed forest ecosystems in Nigeria

BOIS & FORETS DES TROPIQUES ◽

10.19182/bft2021.349.a36779 ◽

2021 ◽

Vol 349 ◽

pp. 41-54

Author(s):

Friday Nwabueze OGANA ◽

José Javier GORGOSO-VARELA ◽

Alfred Ossai ONEFELI

Keyword(s):

Forest Ecosystems ◽

Management Practice ◽

Mixed Forest ◽

Basal Area ◽

Selection Method ◽

Maximum Diameter ◽

Mixed Stands ◽

Mixed Forests ◽

Breast Height ◽

Silvicultural Treatments

The absence of management practice/silvicultural treatments in the complex tropical mixed forests of Nigeria has led to uncontrolled logging in natural forest stands and loss of biodiversity. To sustain production, protection and conservation in these complex tropical mixed stands, this study proposes the application of a selection method – the BDq method (B: basal area, D: maximum diameter, q-ratio) to manage these stands. Two strata were used as a pilot test: stratum 1 consisted of 15 plots and stratum 2 of 7 plots, each with an area of 0.25 ha. Only trees with a diameter at breast height (d) ≥ 10.0 cm were considered in this study. Harvesting with the BDq method was quantified, by setting B at 20 m2, 25 m2 and 30 m2/ha corresponding respectively to intensive, medium and light harvesting regimes. D was set at 65 cm and the q-ratio was computed for each plot. The results showed that the three BDq regimes prescribed (intensive, medium and light) yielded reasonable felling intensities (FI), derived as the percentage of extracted volume (Vext) and biomass (Wext). The Vext and FI for stratum 1 ranged from 39.94-62.30 m3/ha and 11.22-18.18%; the results for stratum 2 were 30.44-51.33 m3/ha and 10.02-17.57%. For biomass, the Wext and FI ranged from 18.46-29.82 t/ha and 9.40-15.95% for stratum 1 and 14.16-24.82 t/ha and 9.73-17.50% for stratum 2. These findings show that applying the BDq method to the complex tropical mixed forests of Nigeria would yield attractive stands.

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