scholarly journals Tree-, stand- and site-specific controls on landscape-scale patterns of transpiration

2017 ◽  
Author(s):  
Sibylle K. Hassler ◽  
Markus Weiler ◽  
Theresa Blume
Keyword(s):  
Spatial Variability ◽  
Sap Flow ◽  
Temporal Dynamics ◽  
Stand Density ◽  
Landscape Scale ◽  
Tree Stand ◽  
Site Specific ◽  
As Species ◽  
Individual Trees ◽  
Transfer Models

Abstract. Transpiration is a key process in the hydrological cycle and a sound understanding and quantification of transpiration and its spatial variability is essential for management decisions as well as for improving the parameterisation of hydrological and soil–vegetation–atmosphere transfer models. For individual trees, transpiration is commonly estimated by measuring sap flow. Besides evaporative demand and water availability, tree-specific characteristics such as species, size or social status control sap flow amounts of individual trees. Within forest stands, properties such as species composition, basal area or stand density additionally affect sap flow, for example via competition mechanisms. Finally, sap flow patterns might also be influenced by landscape-scale characteristics such as geology, slope position or aspect because they affect water and energy availability; however, little is known about the dynamic interplay of these controls. We studied the relative importance of various tree-, stand- and site-specific characteristics with multiple linear regression models to explain the variability of sap velocity measurements in 61 beech and oak trees, located at 24 sites spread over a 290 km2-catchment in Luxembourg. For each of 132 consecutive days of the growing season of 2014 we modelled the daily sap velocities of these 61 trees and determined the importance of the different predictors. Results indicate that a combination of tree-, stand- and site-specific factors controls sap velocity patterns in the landscape, namely tree species, tree diameter, the stand density, geology and aspect. Compared to these predictors, spatial variability of atmospheric demand and soil moisture explains only a small fraction of the variability in the daily datasets. However, the temporal dynamics of the explanatory power of the tree-specific characteristics, especially species, are correlated to the temporal dynamics of potential evaporation. Thus, transpiration estimates at the landscape scale would benefit from not only considering hydro-meteorological drivers, but also including tree, stand and site characteristics in order to improve the spatial representation of transpiration for hydrological and soil–vegetation–atmosphere transfer models.

scholarly journals Tree-, stand- and site-specific controls on landscape-scale patterns of transpiration

2018 ◽  
Vol 22 (1) ◽  
pp. 13-30 ◽  
Author(s):  
Sibylle Kathrin Hassler ◽  
Markus Weiler ◽  
Theresa Blume
Keyword(s):  
Spatial Variability ◽  
Sap Flow ◽  
Temporal Dynamics ◽  
Flow Patterns ◽  
Landscape Scale ◽  
Tree Stand ◽  
Site Specific ◽  
As Species ◽  
Individual Trees ◽  
Transfer Models

Abstract. Transpiration is a key process in the hydrological cycle, and a sound understanding and quantification of transpiration and its spatial variability is essential for management decisions as well as for improving the parameterisation and evaluation of hydrological and soil–vegetation–atmosphere transfer models. For individual trees, transpiration is commonly estimated by measuring sap flow. Besides evaporative demand and water availability, tree-specific characteristics such as species, size or social status control sap flow amounts of individual trees. Within forest stands, properties such as species composition, basal area or stand density additionally affect sap flow, for example via competition mechanisms. Finally, sap flow patterns might also be influenced by landscape-scale characteristics such as geology and soils, slope position or aspect because they affect water and energy availability; however, little is known about the dynamic interplay of these controls. We studied the relative importance of various tree-, stand- and site-specific characteristics with multiple linear regression models to explain the variability of sap velocity measurements in 61 beech and oak trees, located at 24 sites across a 290 km2 catchment in Luxembourg. For each of 132 consecutive days of the growing season of 2014 we modelled the daily sap velocity and derived sap flow patterns of these 61 trees, and we determined the importance of the different controls. Results indicate that a combination of mainly tree- and site-specific factors controls sap velocity patterns in the landscape, namely tree species, tree diameter, geology and aspect. For sap flow we included only the stand- and site-specific predictors in the models to ensure variable independence. Of those, geology and aspect were most important. Compared to these predictors, spatial variability of atmospheric demand and soil moisture explains only a small fraction of the variability in the daily datasets. However, the temporal dynamics of the explanatory power of the tree-specific characteristics, especially species, are correlated to the temporal dynamics of potential evaporation. We conclude that transpiration estimates on the landscape scale would benefit from not only consideration of hydro-meteorological drivers, but also tree, stand and site characteristics in order to improve the spatial and temporal representation of transpiration for hydrological and soil–vegetation–atmosphere transfer models.

scholarly journals QuickBird image-based estimation of tree stand density using local maxima filtering method: A case study in a Beijing forest

PLoS ONE ◽  
2018 ◽  
Vol 13 (12) ◽  
pp. e0208256
Author(s):  
Shuhan Wang ◽  
Xiaoli Zhang ◽  
Mohammed Abdelmanan Hassan ◽  
Qi Chen ◽  
Chaokui Li ◽  
...  
Keyword(s):  
Stand Density ◽  
Tree Stand ◽  
Local Maxima ◽  
Filtering Method

Quantifying the influence of individual trees on slope stability at landscape scale

2021 ◽  
Vol 286 ◽  
pp. 112194
Author(s):  
Raphael I. Spiekermann ◽  
Sam McColl ◽  
Ian Fuller ◽  
John Dymond ◽  
Lucy Burkitt ◽  
...  
Keyword(s):  
Slope Stability ◽  
Landscape Scale ◽  
Individual Trees

Tree diversity and natural regeneration in Tropical Dry Deciduous Forest of Panna Tiger Reserve, India

2021 ◽  
Author(s):  
Talat Parveen ◽  
Orus Ilyas
Keyword(s):  
Species Diversity ◽  
Tree Species ◽  
Deciduous Forest ◽  
Basal Area ◽  
Stand Density ◽  
Tectona Grandis ◽  
Aegle Marmelos ◽  
Tree Stand ◽  
Tiger Reserve ◽  
Dry Deciduous Forest

Abstract The disturbance is a major factor driving the decline of tropical forests and their associated fauna. Henceforth, basic information on species diversity would be useful for assessing the success of management in the fragmented and human-disturbed landscape. We accounted for tree species diversity and their regeneration pattern from the tropical dry deciduous forest of Panna Tiger Reserve (PTR), India. Considering this, random vegetation sampling along with transects was carried out in different ranges of PTR. It is spread over in an area of 2998.98 km2 that situated in the northern part of Madhya Pradesh and distributed in Panna and Chhatarpur district. The tropical dry deciduous forest inventory in the 10.6132-ha area yielded a total of 46 woody species of > 10 cm GBH, belonged to 23 Families and 40 genera. The regeneration represented 27 species of < 30 cm height (seedling) under 16 families and 24 genera while sapling, which ranges from > 30cm to 1.3m, showed 24 species of 13 families and 32 genera. The Shannon diversity of Trees, seedlings, and saplings was 2.684, 2.525, and 2.401 respectively. A total stand density and basal area of 2391 stems of trees were estimated as 225.285 stand ha− 1 and 90.016 m2ha− 1 respectively. Tectona grandis scored the highest IVI value of 59.44 (19.81% of total IVI for all species) among the dominated tree species, followed by Acacia catechu (24.94), Abrus precatorius (23.25), Zizyphus xylopyra (22.94), Anogeissus latifolia (22.16) and Lagerstroemia parviflora (22.18). Nearly 23.913% of the total number of species was recorded as rare species. The highest seedling density was obtained for Diospyros melanoxylon followed by Zizyphus xylopyra, Aegle marmelos, Wrightia tintoria, and Tectona grandis, which declined in the subsequent sapling stage and showed a reverse pattern. Hence, the highest sapling density was recorded for Tectona grandis then Aegle marmelos, Wrightia tintoria, Diospyros melanoxylon, and Zizyphus xylopyra. A total of 36.956% of tree species were found to fail to establish in the community because species were represented by only adult or tree stage that listed as Not-regenerating. In terms of the most diverse family among the plant categories; viz. Tree, Seedling, Sapling, Fabaceae had the highest species richness. The highest tree stand density (127.576 stand ha− 1) was recorded in the girth class of 31-60cm (48.687% of the total tree stand density) followed by 10-30cm and 61-90cm. Likewise, a total basal area of 20.824 m2ha− 1 was occupied by 31-60cm that contributed 23.051% of the total basal area, so our data on the population structure of forest shows a similar trend wherein the distribution curve exponentially decreases with increasing girth classes that indicates not only a mid-successional forest but also a human-disturbed.

Improved analysis of thermally sensed crop water status and mapping spatial variability for site specific irrigation scheduling

2008 ◽  
Author(s):  
Victor Alchanatis ◽  
Steven Evett ◽  
Shabtai Cohen ◽  
Yafit Cohen ◽  
Moshe Meron ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Water Status ◽  
Irrigation Scheduling ◽  
Crop Water ◽  
Site Specific

scholarly journals Identifying essential ecological factors underpinning the development of a conservation plan for the Endangered Australian tree Alectryon ramiflorus

Oryx ◽  
2015 ◽  
Vol 49 (3) ◽  
pp. 453-460 ◽  
Author(s):  
Peter J. Brown ◽  
Kevin R. Wormington ◽  
Philip Brown
Keyword(s):  
Soil Chemistry ◽  
Vegetation Type ◽  
Ecological Factors ◽  
Iucn Red List ◽  
Habitat Requirements ◽  
As Species ◽  
Disjunct Populations ◽  
Conservation Plan ◽  
Sparse Population ◽  
Individual Trees

AbstractReintroduction of rare and threatened species often fails to yield quantifiable conservation benefits because insufficient attention is focused on the species’ habitat requirements and biology. We demonstrate the value of such data in informing a recovery plan for Alectryon ramiflorus S.Reyn. (Sapindaceae), a tree species endemic to a region on the southern coast of Queensland, Australia. When the species was categorized as Endangered on the IUCN Red List in 1997 the total known population consisted of only 26 adult plants, in five disjunct populations in remnant patches of native vegetation. Analysis of vegetation type, soil chemistry and composition data comparing remnant patches with and without A. ramiflorus revealed that the species is not restricted to a specific soil type but prefers sites with relatively fertile soil and a more complex vegetation structure. The species is cryptically dioecious, displays asynchronous flowering between individuals, and requires insect-vectored pollination. The low rate of seedling production recorded within individual patches was attributed to the scarcity of trees of both genders, asynchronous flowering of individual trees and, in smaller patches, a sparse population of pollinating insect species. Successful reintroduction of A. ramiflorus will require consideration of these aspects of demographic success. The findings highlight the importance to species recovery plans of the knowledge of habitat requirements, interspecific relationships and critical dependencies, as well as species reproductive biology.

Spatial variability and temporal dynamics of HABs in Northeast China

2018 ◽  
Vol 90 ◽  
pp. 280-294 ◽  
Author(s):  
Chong Fang ◽  
Kaishan Song ◽  
Lin Li ◽  
Zhidan Wen ◽  
Ge Liu ◽  
...  
Keyword(s):  
Spatial Variability ◽  
Northeast China ◽  
Temporal Dynamics

scholarly journals Effects of Spatial Variability and Relic DNA Removal on the Detection of Temporal Dynamics in Soil Microbial Communities

mBio ◽  
2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Paul Carini ◽  
Manuel Delgado-Baquerizo ◽  
Eve-Lyn S. Hinckley ◽  
Hannah Holland‐Moritz ◽  
Tess E. Brewer ◽  
...  
Keyword(s):  
Microbial Community ◽  
Spatial Variability ◽  
Spatial Heterogeneity ◽  
Microbial Communities ◽  
Temporal Variability ◽  
Temporal Dynamics ◽  
Microbial Community Composition ◽  
Soil Microbial Communities ◽  
Environmental Preferences ◽  
Soil Microbial

ABSTRACT Few studies have comprehensively investigated the temporal variability in soil microbial communities despite widespread recognition that the belowground environment is dynamic. In part, this stems from the challenges associated with the high degree of spatial heterogeneity in soil microbial communities and because the presence of relic DNA (DNA from dead cells or secreted extracellular DNA) may dampen temporal signals. Here, we disentangle the relationships among spatial, temporal, and relic DNA effects on prokaryotic and fungal communities in soils collected from contrasting hillslopes in Colorado, USA. We intensively sampled plots on each hillslope over 6 months to discriminate between temporal variability, intraplot spatial heterogeneity, and relic DNA effects on the soil prokaryotic and fungal communities. We show that the intraplot spatial variability in microbial community composition was strong and independent of relic DNA effects and that these spatial patterns persisted throughout the study. When controlling for intraplot spatial variability, we identified significant temporal variability in both plots over the 6-month study. These microbial communities were more dissimilar over time after relic DNA was removed, suggesting that relic DNA hinders the detection of important temporal dynamics in belowground microbial communities. We identified microbial taxa that exhibited shared temporal responses and show that these responses were often predictable from temporal changes in soil conditions. Our findings highlight approaches that can be used to better characterize temporal shifts in soil microbial communities, information that is critical for predicting the environmental preferences of individual soil microbial taxa and identifying linkages between soil microbial community composition and belowground processes. IMPORTANCE Nearly all microbial communities are dynamic in time. Understanding how temporal dynamics in microbial community structure affect soil biogeochemistry and fertility are key to being able to predict the responses of the soil microbiome to environmental perturbations. Here, we explain the effects of soil spatial structure and relic DNA on the determination of microbial community fluctuations over time. We found that intensive spatial sampling was required to identify temporal effects in microbial communities because of the high degree of spatial heterogeneity in soil and that DNA from nonliving sources masks important temporal patterns. We identified groups of microbes with shared temporal responses and show that these patterns were predictable from changes in soil characteristics. These results provide insight into the environmental preferences and temporal relationships between individual microbial taxa and highlight the importance of considering relic DNA when trying to detect temporal dynamics in belowground communities.

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