scholarly journals Regeneration dynamics in fragmented landscapes at the leading edge of distribution: Quercus suber woodlands as a study case

2021 ◽  
Author(s):  
Jorge Luis Montero-Muñoz ◽  
Carmen Ureña ◽  
Diego Navarro ◽  
Valentín Herrera ◽  
Pilar Alonso-Rojo ◽  
...  
Keyword(s):  
Tree Growth ◽  
Quercus Suber ◽  
Forest Recovery ◽  
Tree Cover ◽  
Distribution Area ◽  
Soil Parameters ◽  
Old Fields ◽  
Summer Drought ◽  
Regeneration Dynamics ◽  
Positive Effect

Abstract Aims We studied the regeneration dynamics of woodlands and abandoned old fields in a landscape dominated by Quercus suber in its lower limits of rainfall and temperature. Two hypotheses were established: (1) regeneration of Quercus species is strongly favored by the presence of tree cover; and (2) growth of Q. suber is driven by the climatic variables that represent the lower ecological limit of its leading distribution edge. Methods We selected woodlands and old fields with and without tree remnants (n = 3 per type), and analyzed stand structure, soil parameters and tree growth. Results Succession was arrested in old fields without tree remnants. By contrast, remnant trees were accelerators of forest recovery in old fields. Tree cover played a fundamental role in Quercus recruitment throughout seed dispersal and facilitation that mitigate the effects of summer drought on seedlings. Also, tree cover improved soil parameters (e.g., organic matter) that are important factors for understanding differences in regeneration. Winter/spring precipitation exerted a positive effect on tree growth, as well as temperatures during winter/spring and September. Conclusions Regeneration dynamics are modeled by the density of tree cover in the cold and dry edge of the distribution area of Q. suber where Q. ilex is increasing in abundance. Although temperature has a positive effect on the tree growth of Q. suber, when demographic processes are considered, decreases in water availability likely play a critical role in Q. ilex recruitment. This in turn changes dominance hierarchies, especially in abandoned areas with little or no tree cover.

scholarly journals Regeneration Dynamics in Fragmented Landscapes at the Leading Edge of Distribution: Quercus Suber L. as A Study Case

2021 ◽  
Author(s):  
Jorge Montero-Muñoz ◽  
Carmen Ureña ◽  
Diego Navarro ◽  
Valentín Herrera ◽  
Pilar Alonso-Rojo ◽  
...  
Keyword(s):  
Tree Growth ◽  
Quercus Suber ◽  
Forest Recovery ◽  
Tree Cover ◽  
Distribution Area ◽  
Soil Parameters ◽  
Old Fields ◽  
Summer Drought ◽  
Regeneration Dynamics ◽  
Positive Effect

Abstract AimsWe studied the regeneration dynamics of woodlands and abandoned old fields in a landscape dominated by Quercus suber in its lower limits for rainfall and temperature. Two hypotheses were established: (1) recruitment of Q. suber is restricted more by abiotic variations than other species adapted to more extreme Mediterranean conditions; and (2) decreases in precipitation reduce growth, but temperature positively affects growth in the leading cold edge of this species distribution area.MethodsWe selected nine sites containing forest stands and old fields with and without tree remnants, and analyzed stand structure, soil parameters and tree growth.ResultsSuccession was arrested in plots without tree remnants after cultivation abandonment. By contrast, remnant trees were accelerators of forest recovery. Tree cover played a fundamental role in Quercus recruitment throughout seed dispersal and facilitation effects that ameliorate summer drought. However, soil variables also significantly explained much of the variance observed and are important for understanding differences in regeneration. Winter and spring precipitation exerted a positive effect on tree growth, as well as temperatures during winter/spring and September.ConclusionsRegeneration dynamics are modeled by the density of tree cover in the cold and dry edge of the distribution area of Q. suber where Q. ilex is increasing in abundance. Although temperature has a positive effect on the tree growth of Q. suber, when demographic processes are considered, decreases in water availability likely play a critical role in Q. ilex recruitment. This in turn changes dominance hierarchies, especially in abandoned areas with little or no tree cover.

scholarly journals Nematode Populations and Peach Tree Survival, Growth, and Nutrition at an Old Orchard Site

1992 ◽  
Vol 117 (1) ◽  
pp. 6-13 ◽  
Author(s):  
Dean R. Evert ◽  
Paul F. Bertrand ◽  
`Benjamin G. Mullinix
Keyword(s):  
Tree Growth ◽  
Prunus Persica ◽  
Paspalum Notatum ◽  
Parasitic Nematodes ◽  
Severe Stunting ◽  
Growth And Nutrition ◽  
Tree Survival ◽  
Peach Trees ◽  
Positive Effect ◽  
Survival Tree

Bahiagrass (Paspalum notatum Flugge cv. Paraguayan-22) growing under newly planted peach [Prunus persica (L.) Batsch.] trees severely stunted the trees. Neither supplemental fertilizer nor irrigating with two 3.8-liters·hour-1 emitters per tree eliminated tree stunting emitters were controlled by an automatic tensiometer set to maintain 3 kpa at a depth of 0.5 m under a tree in bahiagrass. Preplant fumigation with ethylene dibromide at 100 liters·ha-1 increased tree growth, but not tree survival. Fenamiphos, a nematicide, applied under the trees each spring and fall at a rate of 11 kg-ha -1 had no positive effect on tree survival, tree growth, or nematode populations. Bahiagrass tended to suppress populations of Meloidogyne spp. under the trees., Meloidogyne spp. were the only nematodes present that had mean populations > 65 per 150 cm3 of soil. Leaf concentrations of several elements differed between trees growing in bahiagrass sod and in. bare ground treated with herbicides. Leaf Ca was low for all treatments in spite of a soil pH near 6.5 and adequate soil Ca. The severe stunting of trees grown in bahiagrass, irrespective of the other treatments, demonstrated that bahiagrass should not be grown under newly planted trees. The low populations of parasitic nematodes in bahiagrass showed that bahiagrass has potential as a preplant biological control of nematodes harmful to peach trees. Chemical name used: ethyl 3-methy1-4-(methylthio) phenyl (1-methylethyl) phosphoramidate (fenamiphos).

scholarly journals Implications of Reduced Stand Density on Tree Growth and Drought Susceptibility: A Study of Three Species under Varying Climate

Forests ◽  
2020 ◽  
Vol 11 (6) ◽  
pp. 627
Author(s):  
Mathias Steckel ◽  
W. Keith Moser ◽  
Miren del Río ◽  
Hans Pretzsch
Keyword(s):  
Scots Pine ◽  
Tree Growth ◽  
Water Availability ◽  
Ponderosa Pine ◽  
Stand Density ◽  
Stand Age ◽  
Short Term ◽  
Sessile Oak ◽  
Site Water ◽  
Positive Effect

A higher frequency of increasingly severe droughts highlights the need for short-term measures to adapt existing forests to climate change. The maintenance of reduced stand densities has been proposed as a promising silvicultural tool for mitigating drought stress. However, the relationship between stand density and tree drought susceptibility remains poorly understood, especially across ecological gradients. Here, we analysed the effect of reduced stand density on tree growth and growth sensitivity, as well as on short-term drought responses (resistance, recovery, and resilience) of Scots pine (Pinus sylvestris L.), sessile oak (Quercus petraea (Matt.) Liebl.), and ponderosa pine (Pinus ponderosa Douglas ex C. Lawson). Tree ring series from 409 trees, growing in stands of varying stand density, were analysed at sites with different water availability. For all species, mean tree growth was significantly higher under low compared with maximum stand density. Mean tree growth sensitivity of Scots pine was significantly higher under low compared with moderate and maximum stand density, while growth sensitivity of ponderosa pine peaked under maximum stand density. Recovery and resilience of Scots pine, as well as recovery of sessile oak and ponderosa pine, decreased with increasing stand density. In contrast, resistance and resilience of ponderosa pine significantly increased with increasing stand density. Higher site water availability was associated with significantly reduced drought response indices of Scots pine and sessile oak in general, except for resistance of oak. In ponderosa pine, higher site water availability significantly lessened recovery. Higher site water availability significantly moderated the positive effect of reduced stand density on drought responses. Stand age had a significantly positive effect on the resistance of Scots pine and a negative effect on recovery of sessile oak. We discuss potential causes for the observed response patterns, derive implications for adaptive forest management, and make recommendations for further research in this field.

Removal of Climbing Plants and Soil Plowing as a Strategy to Enhance Forest Recovery in Tropical Dry Forests Old Fields

2019 ◽  
Vol 37 (2) ◽  
pp. 113-122 ◽  
Author(s):  
Moisés Méndez-Toribio ◽  
Julieta Benítez-Malvido ◽  
Isela E. Zermeño-Hernández ◽  
Jessica Castillo-Mandujano
Keyword(s):  
Forest Recovery ◽  
Tropical Dry Forests ◽  
Old Fields ◽  
Dry Forests ◽  
Climbing Plants

scholarly journals Forest Spectral Recovery and Regeneration Dynamics in Stand-Replacing Wildfires of Central Apennines Derived from Landsat Time Series

2019 ◽  
Vol 11 (3) ◽  
pp. 308 ◽  
Author(s):  
Donato Morresi ◽  
Alessandro Vitali ◽  
Carlo Urbinati ◽  
Matteo Garbarino
Keyword(s):  
Vegetation Index ◽  
Rate Of Change ◽  
Tree Canopy ◽  
Forest Recovery ◽  
Central Apennines ◽  
Vegetation Development ◽  
Regeneration Dynamics ◽  
Tree Canopy Cover ◽  
Spectral Recovery ◽  
Normalized Burn Ratio

Understanding post-fire regeneration dynamics is an important task for assessing the resilience of forests and to adequately guide post-disturbance management. The main goal of this research was to compare the ability of different Landsat-derived spectral vegetation indices (SVIs) to track post-fire recovery occurring in burned forests of the central Apennines (Italy) at different development stages. Normalized Difference Vegetation Index (NDVI), Normalized Difference Moisture Index (NDMI), Normalized Burn Ratio (NBR), Normalized Burn Ratio 2 (NBR2) and a novel index called Forest Recovery Index 2 (FRI2) were used to compute post-fire recovery metrics throughout 11 years (2008–2018). FRI2 achieved the highest significant correlation (Pearson’s r = 0.72) with tree canopy cover estimated by field sampling (year 2017). The Theil–Sen slope estimator of linear regression was employed to assess the rate of change and the direction of SVIs recovery metrics over time (2010–2018) and the Mann–Kendall test was used to evaluate the significance of the spectral trends. NDVI displayed the highest amount of recovered pixels (38%) after 11 years since fire occurrence, whereas the mean value of NDMI, NBR, NBR2, and FRI2 was about 27%. NDVI was more suitable for tracking early stages of the secondary succession, suggesting greater sensitivity toward non-arboreal vegetation development. Predicted spectral recovery timespans based on pixels with a statistically significant monotonic trend did not highlight noticeable differences among normalized SVIs, suggesting similar suitability for monitoring early to mid-stages of post-fire forest succession. FRI2 achieved reliable results in mid- to long-term forest recovery as it produced up to 50% longer periods of spectral recovery compared to normalized SVIs. Further research is needed to understand this modeling approach at advanced stages of post-fire forest recovery.

Woody debris and tree regeneration dynamics following severe wildfires in Arizona ponderosa pine forests

2012 ◽  
Vol 42 (3) ◽  
pp. 593-604 ◽  
Author(s):  
John P. Roccaforte ◽  
Peter Z. Fulé ◽  
W. Walker Chancellor ◽  
Daniel C. Laughlin
Keyword(s):  
Pinus Ponderosa ◽  
Forest Fires ◽  
Ponderosa Pine ◽  
Woody Debris ◽  
Climatic Conditions ◽  
Pine Forest ◽  
Tree Regeneration ◽  
Forest Recovery ◽  
Regeneration Dynamics ◽  
Ponderosa Pine Forests

Severe forest fires worldwide leave behind large quantities of dead woody debris and regenerating trees that can affect future ecosystem trajectories. We studied a chronosequence of severe fires in Arizona, USA, spanning 1 to 18 years after burning to investigate postfire woody debris and regeneration dynamics. Snag densities varied over time, with predominantly recent snags in recent fires and broken or fallen snags in older fires. Coarse woody debris peaked at > 60 Mg/ha in the time period 6–12 years after fire, a value higher than previously reported in postfire fuel assessments in this region. However, debris loadings on fires older than 12 years were within the range of recommended management values (11.2–44.8 Mg/ha). Overstory and regeneration were most commonly dominated by sprouting deciduous species. Ponderosa pine ( Pinus ponderosa C. Lawson var. scopulorum Engelm.) overstory and regeneration were completely lacking in 50% and 57% of the sites, respectively, indicating that many sites were likely to experience extended periods as shrublands or grasslands rather than returning rapidly to pine forest. More time is needed to see whether these patterns will remain stable, but there are substantial obstacles to pine forest recovery: competition with sprouting species and (or) grasses, lack of seed sources, and the forecast of warmer, drier climatic conditions for coming decades.

scholarly journals Morphological and Physiological Characteristics of the Representatives of Melilotus Albus and Melilotus Officinalis, Growing on the Territory of Kalmykia

2019 ◽  
Author(s):  
V. I. Dordzhieva ◽  
T. V. Voloshina ◽  
K. S. Ochirova
Keyword(s):  
Leaf Tissue ◽  
Structural Features ◽  
Anatomical Structure ◽  
Physiological Characteristics ◽  
Summer Drought ◽  
Diagnostic Features ◽  
Melilotus Officinalis ◽  
Arid Conditions ◽  
Melilotus Albus ◽  
Positive Effect

A comparative analysis of leaf blades of two kinds of clover (Melilotus albus, Melilotus officinalis) growing on the territory of Kalmykia has been carried out. Identified diagnostic features in the anatomical structure of the leaves of each species. The parameters of leaf tissue are set. The results of the work give an idea of the degree of plasticity of a characteristic of a leaf plate of two types of clover. Demonstrated features of plates of the same species can be equally, as well as specific for this species, and adaptive variability, due to which the plant has adapted to life in arid conditions. The water regime, indicators of transpiration and productivity of the clover were studied. Changes in physiological parameters were determined before the onset of the summer drought and at its height. The established morphological and physiological characteristics of the two species of clover allow them to be defined as plants that are well adapted to growing under the arid conditions of Kalmykia. The combination of the structural features of the clover with its physiological capabilities, valuable feeding properties and a positive effect on the soil, testifies to the effectiveness of the use of clover in the lean, saline areas of the region. The obtained data can be used in further systematic studies of the genus Melilotus, as well as in planning reclamation measures.

scholarly journals The Radial Growth of Picea wilsonii Was More Restricted by Precipitation Due to Climate Warming on Mt. Guandi, China

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1602
Author(s):  
Xiaoxia Huang ◽  
Xiaoneng Sun ◽  
Yuan Jiang ◽  
Feng Xue ◽  
Minghao Cui ◽  
...  
Keyword(s):  
Climate Warming ◽  
Tree Growth ◽  
Radial Growth ◽  
Management Strategies ◽  
Ring Width ◽  
Elevational Gradient ◽  
Summer Drought ◽  
Clear Trend ◽  
Biological Variables ◽  
Picea Wilsonii

Transitional climate zones (TCZ) are characterized by instability due to rapid changes in climate and biological variables, and trees growing there are particularly sensitive to climate change. Therefore, knowledge about the shifted relationships of tree growth in response to climate warming will shape regional forest conservation and management strategies. China has experienced rapid warming in recent decades. However, how tree growth in semihumid to semiarid regions, such as the Guandi Mountains, responds to more sophisticated changes in the hydrothermal combination is not yet clear. In this study, we used tree-ring width data from three sites along an elevational gradient in the Guandi Mountains to present the response of Picea wilsonii Mast. radial growth to increasing temperature and elevational differences in the relationship between tree growth and climate. The results indicated that the Guandi Mountains have experienced rapid warming with a clear trend toward aridity. From 1959 to 1995, the radial growth of P. wilsonii was mainly influenced by temperature, while it was controlled by both temperature and precipitation after rapid warming in 1996. From 1959 to 2017, this species showed a generally consistent growth–climate relationship at different elevations in the Guandi Mountains. However, the radial growth of trees at higher elevations had a higher climatic correlation than at lower elevations, and it was more conditioned by higher summer temperatures and precipitation in December of the previous year. These results suggested that P. wilsonii was more susceptible to drought and high temperatures due to a warming climate and that more attention should be devoted to forest management, especially the adverse consequences of summer drought on P. wilsonii.

scholarly journals Intra-Annual Wood Formation of Cryptomeria fortunei and Cunninghamia lanceolata in Humid Subtropical China

2021 ◽  
Vol 9 ◽  
Author(s):  
Zhuangpeng Zheng ◽  
Feifei Zhou ◽  
Patrick Fonti ◽  
Ping Ren ◽  
Xiaoxia Li ◽  
...  
Keyword(s):  
Climate Change ◽  
Tree Growth ◽  
Boreal Forests ◽  
Cambial Activity ◽  
Cunninghamia Lanceolata ◽  
Growth Monitoring ◽  
Specific Information ◽  
Summer Drought ◽  
Growth Responses ◽  
Xylem Growth

Monitoring cambial activity is important for a better understanding of the mechanisms governing xylem growth responses to climate change, providing a scientific basis for tree-ring-based climate reconstructions and projections about tree growth under future climate scenarios. It plays an even more important role in investigating evergreen tree growth in regions with less distinct seasonal cycles. Subtropical evergreen forests have been studied in recent years for their sensitivity to climate change, but it remains unclear how xylem growth is driven by subtropical climates. To further understand the climate-growth response strategies of subtropical conifers, we micro-cored Cryptomeria fortunei and Cunninghamia lanceolata weekly in 2016 and 2017 at the humid subtropical Gushan Mountain in southeastern China. Our weekly growth monitoring showed that the vegetation periods of these two species were both approximately 2–3 months longer than trees in temperate and boreal forests. The growth of C. fortunei in 2016 and 2017 and C. lanceolata in 2017 showed a bimodal pattern of xylogenesis, which was induced by summer drought. The results also indicated that the earlier end of the xylem formation was related to the yearly drought stress. These findings provide more specific information about tree growth and evidence of how climate influences wood production at the cellular level in subtropical regions.

Regeneration of submediterranean species Euonymus latifolius (L.) Mill. at its southernmost limit in Europe

2021 ◽  
Vol 42 ◽  
pp. e68137
Author(s):  
Daniel Agea ◽  
Sandra García-de Lucas ◽  
Juan Lorite
Keyword(s):  
Population Structure ◽  
Critical Role ◽  
Tree Canopy ◽  
Soil Parameters ◽  
Mediterranean Species ◽  
Increasing Temperature ◽  
Number Of Individuals ◽  
Positive Effect ◽  
Dense Tree

Due to the ongoing effects of climate change in the Mediterranean (increasing temperature and decreasing rainfall), conditions for Submediterranean species are disappearing as their habitats are dwindling. We have focused on Euonymus latifolius (L.) Mill., a nemoral-Submediterranean species, at its southernmost populations of Europe. The aim was to evaluate the population structure and regeneration niche of the species at microhabitat scale. We selected five larger populations among the 13 existing ones, marking 25-30 individuals per population. We measured twice: height, width, vegetation cover, survival, soil moisture and temperature. As result, we provided data of the 13 existing populations, containing 93 adults and 350 juveniles. Moreover, we have obtained a very skew population structure with a low number of recruits for five selected populations, especially at smaller populations. Most E. latifolius juveniles were encountered under dense tree canopy (more than 80 % in cover) formed by a mixture of Submediterranean and Mediterranean species. Biovolume per population showed significant differences among the main populations CP and CV, presenting this last a higher recruitment, while recruitment was very low in general. For soil parameters, we found a critical role of canopy, which showed a positive effect on juvenile microhabitat (higher moisture and lower soil temperature). The results showed us the critical situation of the species, with very fragmented populations, low number of individuals, and scattered spatial patterns of individuals within the populations. Also, survival problems, a non-balance demographic structure, and regeneration problems were detected. Finally, we propose a sere of conservation measures, from monitoring to active measures (key tree species plantation, reintroduction, reinforcements), combined with threat control (herbivory, pests, and impact from outdoor activities). All combined may help to preserve this species at its southernmost populations.

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