scholarly journals Analysis of cambial activity and formation of wood in Quercus robur L. under conditions of a floodplain forest

2012 ◽  
Vol 49 (No. 9) ◽  
pp. 412-418 ◽  
Author(s):  
P. Horáček ◽  
J. Šlezingerová ◽  
L. Gandelová
Keyword(s):  
Quercus Robur ◽  
Ecological Factors ◽  
Growth Curves ◽  
Growing Season ◽  
Cambial Activity ◽  
Wood Formation ◽  
Floodplain Forest ◽  
Pedunculate Oak ◽  
Total Production ◽  
The Social

The analyses of the activity of cambium and the study of the increment of wood during one growing season of pedunculate oak (Quercus robur L.) under conditions of a floodplain forest is provided. The following parameters were studied: the beginning and end of the cambial activity, differentiation of wood fibres (libriform) and vessels and analysis of the total increment of wood during vegetation in dominant (D), co-dominant (CD) and subdominant (SD) trees in relation to ecological factors of the environment. The course of wood formation corresponds to typical growth curves which are modified by factors of the environment (mean daily temperature, precipitation, soil water supply). The rate of growth is limited by factors of the environment and under the lack of some of them it is reduced resulting in the decrease in the total production of cells. Oak is a species sensitively responding to the period of drought which is particularly manifested in wood increment in subdominant trees. Sufficient supplies of water during spring months accelerate the formation of early wood including differentiation of spring vessels as corroborated by the results. The total formation of wood is dependent not only on the characteristics of the respective growing season but particularly on the social position of trees in the stand.

scholarly journals Temporal dynamics of nonstructural carbohydrates and xylem growth in Pinus sylvestris exposed to drought

2011 ◽  
Vol 41 (8) ◽  
pp. 1590-1597 ◽  
Author(s):  
Walter Oberhuber ◽  
Irene Swidrak ◽  
Daniela Pirkebner ◽  
Andreas Gruber
Keyword(s):  
Pinus Sylvestris ◽  
Temporal Dynamics ◽  
Growing Season ◽  
Cambial Activity ◽  
Wood Formation ◽  
Nonstructural Carbohydrates ◽  
Late Wood ◽  
Structural Growth ◽  
Xylem Growth ◽  
Soil Dryness

Wood formation requires a continuous supply of carbohydrates for structural growth and metabolism. In the montane belt of the central Austrian Alps, we monitored the temporal dynamics of xylem growth and nonstructural carbohydrates (NSC) in stem sapwood of Scots pine ( Pinus sylvestris L.) during the growing season of 2009, which was characterized by exceptional soil dryness within the study area. Soil water content dropped below 10% at the time of maximum xylem growth at the end of May. Histological analyses have been used to describe cambial activity and xylem growth. Determination of NSC was performed using specific enzymatic assays revealing that total NSC ranged from 0.8% to 1.7% dry matter throughout the year. Significant variations (P < 0.05) of the size of the NSC pool were observed during the growing season. Starch showed persistent abundance throughout the year, reaching a maximum shortly before onset of late wood formation in mid-July. Seasonal dynamics of NSC and xylem growth suggest that (i) high sink activity occurred at the start of the growing season in spring and during late wood formation in summer and (ii) there was no particular shortage in NSC, which caused P. sylvestris to draw upon stem reserves more heavily during the drought in 2009.

scholarly journals Forward Modeling Reveals Multidecadal Trends in Cambial Kinetics and Phenology at Treeline

2021 ◽  
Vol 12 ◽  
Author(s):  
Jan Tumajer ◽  
Jakub Kašpar ◽  
Hana Kuželová ◽  
Vladimir V. Shishov ◽  
Ivan I. Tychkov ◽  
...  
Keyword(s):  
Climate Change ◽  
Growth Rates ◽  
Climatic Factors ◽  
Temporal Stability ◽  
Growing Season ◽  
Cambial Activity ◽  
Wood Formation ◽  
Spring Phenology ◽  
Season Extension ◽  
Phenological Phases

Significant alterations of cambial activity might be expected due to climate warming, leading to growing season extension and higher growth rates especially in cold-limited forests. However, assessment of climate-change-driven trends in intra-annual wood formation suffers from the lack of direct observations with a timespan exceeding a few years. We used the Vaganov-Shashkin process-based model to: (i) simulate daily resolved numbers of cambial and differentiating cells; and (ii) develop chronologies of the onset and termination of specific phases of cambial phenology during 1961–2017. We also determined the dominant climatic factor limiting cambial activity for each day. To asses intra-annual model validity, we used 8 years of direct xylogenesis monitoring from the treeline region of the Krkonoše Mts. (Czechia). The model exhibits high validity in case of spring phenological phases and a seasonal dynamics of tracheid production, but its precision declines for estimates of autumn phenological phases and growing season duration. The simulations reveal an increasing trend in the number of tracheids produced by cambium each year by 0.42 cells/year. Spring phenological phases (onset of cambial cell growth and tracheid enlargement) show significant shifts toward earlier occurrence in the year (for 0.28–0.34 days/year). In addition, there is a significant increase in simulated growth rates during entire growing season associated with the intra-annual redistribution of the dominant climatic controls over cambial activity. Results suggest that higher growth rates at treeline are driven by (i) temperature-stimulated intensification of spring cambial kinetics, and (ii) decoupling of summer growth rates from the limiting effect of low summer temperature due to higher frequency of climatically optimal days. Our results highlight that the cambial kinetics stimulation by increasing spring and summer temperatures and shifting spring phenology determine the recent growth trends of treeline ecosystems. Redistribution of individual climatic factors controlling cambial activity during the growing season questions the temporal stability of climatic signal of cold forest chronologies under ongoing climate change.

scholarly journals Influence of the method of grafting on survival and growth of pedunculate oak (Quercus robur L.)

2019 ◽  
pp. 36-42
Author(s):  
I. I. Kamalova ◽  
R. M. Kamalov ◽  
N. I. Vnukova
Keyword(s):  
Root System ◽  
Growth Rates ◽  
Quercus Robur ◽  
Growing Season ◽  
Individual Variability ◽  
Pedunculate Oak ◽  
Split Method ◽  
System A ◽  
Coefficients Of Variation ◽  
Survival And Growth

The aim of the study was to identify the most effective method of grafting the pedunculate oak in greenhouse conditions on two-year-old seedlings with a closed root system. A comparison was made of five methods of grafting on survival and growth of grafts. The following methods were used: «splice», «into a bag», «in split», «budding», «into acorn sprout». The best results in the survival of the grafts were given by the «splice» (42%). The largest increments were shown by the «in split» method (19,0 + 3,1 cm). The distribution of grafting by the magnitude of growth was significantly different from normal. The growth rates of grafting during the growing season had a high individual variability - the coefficients of variation at the age of 36, 60, and 83 days are equal, respectively, to 85, 75, and 73%. In the first growing season, clones did not show any effect on the size of growth. During this period the graft method has the greatest influence, which affects the specificity of the intergrowth of the stock with the graft.

The social wasp Vespula germanica (Fabricius) (Hymenoptera: Vespidae) population dynamics in England over 39 years.

2018 ◽  
Vol 154 (2) ◽  
pp. 149-155
Author(s):  
Michael Archer
Keyword(s):  
Population Dynamics ◽  
Population Dynamic ◽  
Ecological Factors ◽  
Social Wasp ◽  
Data Sets ◽  
Data Set ◽  
Vespula Germanica ◽  
The Social ◽  
Minimum Number ◽  
Suction Traps

1. Yearly records of worker Vespula germanica (Fabricius) taken in suction traps at Silwood Park (28 years) and at Rothamsted Research (39 years) are examined. 2. Using the autocorrelation function (ACF), a significant negative 1-year lag followed by a lesser non-significant positive 2-year lag was found in all, or parts of, each data set, indicating an underlying population dynamic of a 2-year cycle with a damped waveform. 3. The minimum number of years before the 2-year cycle with damped waveform was shown varied between 17 and 26, or was not found in some data sets. 4. Ecological factors delaying or preventing the occurrence of the 2-year cycle are considered.

Scaling leaf photosynthesis to canopy in a mixed deciduous forest. I. model description

1997 ◽  
Vol 62 ◽  
Author(s):  
R. Samson ◽  
S. Follens ◽  
R. Lemeur
Keyword(s):  
Temperature Dependence ◽  
Quercus Robur ◽  
Deciduous Forest ◽  
Growing Season ◽  
Model Description ◽  
Canopy Photosynthesis ◽  
Leaf Photosynthesis ◽  
Layer Model ◽  
Mixed Deciduous Forest ◽  
Leaf Level

A  multi-layer model (FORUG) was developed, to simulate the canopy  photosynthesis of a mixed deciduous forest during the growing season.  Measured photosynthesis parameters, for beech (Fagus  sylvatica), oak (Quercus  robur) and ash (Fraxinus  excelsior), were used as input to the model. This  information at the leaf level is then scaled up to the level of the canopy,  taking into account the radiation profiles (diffuse and direct PAR) in the  canopy, the vertical LAI distribution, the evolution of the LAI and the  photosynthesis parameters during the growing season, and the temperature  dependence of the latter parameters.

Growth and management of mixed Pinus sylvestris - Quercus robur stands in Flanders, Belgium

1993 ◽  
Vol 58 ◽  
Author(s):  
D. Maddelein ◽  
J. Neirynck ◽  
G. Sioen
Keyword(s):  
Pinus Sylvestris ◽  
Natural Regeneration ◽  
Quercus Robur ◽  
Good Growth ◽  
Pedunculate Oak ◽  
Selection System ◽  
Management Options ◽  
Stand Management ◽  
Pine Stands

Mature  Scots pine (Pinus sylvestris  L.) stands are dominating large parts of the Flemish forest area. Broadleaved  species regenerate spontaneously under this pine canopy. This study studied  the growth and development of two planted pine stands with an older natural  regeneration, dominated by pedunculate oak (Quercus  robur L.), and discussed management options for  similar stands.     The results indicated a rather good growth of the stands, with current  annual increments of 5 m3.ha-1.yr-1. The pine overstorey is growing into valuable sawwood  dimensions, while the broadleaved understorey slowly grows into the  upperstorey. The quality of the regeneration is moderate but can be improved  by silvicultural measurements (pruning, early selection).     In both stands, an interesting (timber production, nature conservation)  admixture of secondary tree species is present in the regeneration. Stand  management is evolving from the classical clearcut system towards a  combination of a type of selection and group selection system.

scholarly journals Different climate sensitivity for radial growth, but uniform for tree-ring stable isotopes along an aridity gradient in Polylepis tarapacana, the world’s highest elevation tree-species

2021 ◽  
Author(s):  
Milagros Rodriguez-Caton ◽  
Laia Andreu-Hayles ◽  
Mariano S Morales ◽  
Valérie Daux ◽  
Duncan A Christie ◽  
...  
Keyword(s):  
Stable Isotopes ◽  
Carbon Source ◽  
Tree Ring ◽  
Tree Growth ◽  
Carbon Sink ◽  
Growing Season ◽  
Wood Formation ◽  
Aridity Gradient ◽  
Leaf Level ◽  
Δ13c And Δ18o

Abstract Tree growth is generally considered to be temperature-limited at upper elevation treelines. Yet, climate factors controlling tree growth at semiarid treelines are poorly understood. We explored the influence of climate on stem growth and stable isotopes for Polyepis tarapacana, the world’s highest elevation tree-species found only in the South American Altiplano. We developed tree-ring width index (RWI), oxygen (δ18O) and carbon (δ13C) chronologies for the last 60 years at four P. tarapacana stands located above 4,400 meters in elevation, along a 500-km latitude-aridity gradient. Total annual precipitation decreased from 300 to 200 mm from the northern to the southern sites. We used RWI as a proxy of wood formation (carbon sink) and isotopic tree-ring signatures as proxies of leaf-level gas exchange processes (carbon source). We found distinct climatic conditions regulating carbon-sink processes along the gradient. Current-growing season temperature regulated RWI at wetter-northern sites, while prior-growing season precipitation determined RWI at arid-southern sites. This suggests that the relative importance of temperature to precipitation in regulating tree growth is driven by site-water availability. In contrast, warm and dry growing-seasons resulted in enriched tree-ring δ13C and δ18O at all study sites, suggesting that similar climate conditions control carbon-source processes. Site-level δ13C and δ18O chronologies were significantly and positively related at all sites, with the strongest relationships among the southern-drier stands. This indicates an overall regulation of intercellular carbon dioxide via stomatal conductance for the entire P. tarapacana network, with greater stomatal control when aridity increases. The manuscript also highlights a coupling and decoupling of physiological processes at leaf level versus wood formation depending on their respectively uniform and distinct sensitivity to climate. This study contributes to better understand and predict the response of high-elevation Polylepis woodlands to rapid climate changes and projected drying in the Altiplano.

Factors that affect entomophagical practices in Ghana

2017 ◽  
Vol 3 (1) ◽  
pp. 33-41 ◽  
Author(s):  
P.J. Anankware ◽  
E.A. Osekre ◽  
D. Obeng-Ofori ◽  
C.M. Khamala
Keyword(s):  
Social Factors ◽  
Urban Areas ◽  
Age Groups ◽  
Ecological Factors ◽  
Insect Species ◽  
Edible Insects ◽  
The Social ◽  
Gender Education ◽  
And Gender ◽  
Religious Reasons

This study evaluated the social and ecological factors that affect entomophagy in Ghana with a view to instigate the initiation of programmes for the use of insects for human and poultry nutrition in Africa. Two thousand questionnaires were administered to randomly selected respondents in all the ten regions of Ghana. With regards to social factors, entomophagy was found to be influenced by age, gender, education and occupation. Entomophagy is practiced across all age groups and gender in Ghana. Proportionally, 90, 78 and 74% of the aged (60+), middle aged (31-50) and the youth (18-30), respectively, were observed to consume various insect species. Ecologically, entomophagy was more pronounced in rural than urban areas. Over 87% of respondents who consume edible insects acquire them through harvesting/trapping. Four insect species were identified as feed for animals. The majority (81.6%) of the respondents consume insects as a source of protein, 9.6% for cultural reasons, 5.6% for medicinal values and 3.0 and 0.2%, respectively, for recreational and religious reasons. Gender has the least influence on entomophagy. Considering the economic, ecological and nutritional importance of edible insects in traditional Ghanaian foods, attention should be given to sustainable environmental harvesting practices.

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