Detecting vegetation stress in mixed forest ecosystems through the joint use of tree-water monitoring and land surface modeling

Authorea (Authorea), Год журнала: 2024, Номер unknown

Опубликована: Фев. 16, 2024

Recent European heatwaves have significantly impacted forest ecosystems, leading to increased plant water stress. Advances in land surface models aim improve the representation of vegetation drought responses by incorporating hydraulics into functional type (PFT) classification system. However, reliance on PFTs may inadequately capture diverse hydraulic traits (PHTs), potentially biasing transpiration and stress representations. The detection is further complicated mixing different tree species patches. This study uses Community Land Model version 5.0 simulate an experimental mixed-forest catchment with configurations representing standalone, patched mixed, fully mixed forests. Biome-generic, PFT-specific, or species-specific PHTs are employed. Results emphasize crucial role accurately forests reproducing observed fluxes for both broadleaf needleleaf species. dominant fraction a key determinant, influencing aggregated response patterns. Segregation level PHT parameterizations shapes differences between simulated fluxes. Simulated root potential emerges as metric detecting periods. model’s system has limitations long-term effects extreme weather events These findings highlight complexity modeling underscore need improved diversity enhance understanding under changing climate conditions.

Язык: Английский

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Comparison of Rainfall Partitioning and Estimation of the Utilisation of Available Water in a Monoculture Beech Forest and a Mixed Beech-Oak-Linden Forest

Water, Год журнала: 2023, Номер 15(2), С. 285 - 285

Опубликована: Янв. 9, 2023

Monoculture forests formed by Fagus sylvatica L. belong to one of the most sensitive forest ecosystems, mainly at low altitudes. Cultivation this species in mixed stands should reduce its sensitivity drought vegetation period, which is why we researched water balance pure-beech (i.e., monoculture) and beech–oak–linden mixed) forest. This research was carried out Drahanská vrchovina Czech Republic period 2019–2021. The total precipitation measured, together with partitions throughfall stemflow), crown interception also calculated. transpiration calculated from values measured on sample trees. each rainfall partition (and their percentages) were compared. monoculture differed those While, average, annual percentages throughfall, stemflow 63%, 6% 31%, respectively, these 76%, 2% 22%, respectively. greater (31% precipitation) effective sum stemflow) (78% precipitation). greatest differences (in partition) between summer winter. (ca. 22% ca. 12% winter), 66% 51% winter). mean 318 (±52) mm 451 (±58) forest, i.e., about 99 (±65) more than transpiration, comparison precipitation, made up, 70% On other hand, reached 71% 2019), 74% 2020) even 100% 2021) Our results show that an oak–beech–linden can manage better a beech because leaked through onto soil monoculture, especially via summer. amount transpired monoculture. However, utilisation trees very similar all three years, while, increased, may have been caused saturation deeper layers first two years measurement. We can, Therefore, say that, lower altitudes, it will be suitable future cultivate assumed lack (mainly early spring summer).

Язык: Английский

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Importance of tree diameter and species for explaining the temporal and spatial variations of xylem water δ¹⁸O and δ²H in a multi‐species forest

Ecohydrology, Год журнала: 2023, Номер 16(5)

Опубликована: Март 22, 2023

Abstract Identifying the vegetation and topographic variables influencing isotopic variability of xylem water forest remains crucial to interpret predict ecohydrological processes in landscapes. In this study, we used temporally spatially distributed stable isotopes measurements from two growing seasons examine temporal spatial variations their relationships with a Luxembourgish temperate mixed forest. Species‐specific were observed during both higher for beeches than oaks. Principal component regressions revealed that tree diameter at breast height explains up 55% isotopes, while species 24% variability. Topographic had marginal role explaining (up 6% elevation). During drier season (2020), detected influence on lower signatures wetter (2019). Our results reveal dominant across forested area suggest patterns arise mainly size‐ species‐specific as well availability‐dependent use strategies rather heterogeneity. The identification key has critical implications representativity isotopes‐based catchments studies.

Язык: Английский

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Fast motion view of a headwater creek—A hydrological year seen through time‐lapse photography

Hydrological Processes, Год журнала: 2023, Номер 37(11)

Опубликована: Ноя. 1, 2023

New observational field data have repeatedly been the source of breakthroughs in science, allowing us to learn about things we had not thinking or hypothesized beforehand (Pfister & Kirchner, 2017). For example, increasingly sophisticated field-deployable instruments helped shed light on previously unknown features catchment functioning, such as high-frequency measurements sediment, solutes, and isotopes stream water (e.g., Floury et al., 2017; von Freyberg 2017), continuous sap flow (Granier, 1987), in-situ monitoring isotopic composition tree xylem (Marshall 2020) soil (Volkmann Weiler, 2014), imaging subsurface structure infiltration pathways with electrical resistivity tomography Gourdol 2021; Scaini time-lapse mapping surface-saturation dynamics thermal infrared imagery Glaser 2018; Pfister 2010). Innovative hypotheses generated from novel, integrative, observations offer potential free hydrological concepts restrictions typical datasets. In parallel, recent progress technological development instrumentation has ultimately also revealed more complex landscape heterogeneity. While general organizing principles proposed for coming grips river basins (Loritz Zehe deciphering this heterogeneity remains an important challenge. A major difficulty lies understanding similarities contrasts between hydrologic processes occurring over a wide range spatial temporal scales varying by multiple orders magnitude (Dooge, 2005), e.g., molecules (10−10 m) watershed scale (103 seconds millennia. The drama is that could instrument our catchments point littering, still miss out were looking for. Here, propose use so-called undercranking filming technique (also known photography) go further diagnosing complexity Undercranking consists taking fewer frames camera speeding up action during playback. This offers placing individual wider context, delivering unprecedented view interplay characteristics vegetation cover, soils, topography) functioning storage flux dynamics)—all constantly evolving, but at (very) different time scales. Improving how evolve key better anticipation future trajectories (for under changing climate). We focused Weierbach experimental (WEC)—an interdisciplinary Critical Zone observatory dedicated study hydrological, hydro-geochemical, eco-hydrological processes. Long-term protocols WEC relate fluxes physico-chemical parameters within compartments Zone. rainfall-runoff response characterized strong seasonality—pronounced summer low flows (including occasionally dry periods) winter high flows—resulting (Hissler 2021). installed wildlife (RECONYX Hyperfire 2 Professional White Flash Camera) WEC. device was pointed towards hillslope-riparian zone-stream continuum near v-notch equipped recording gauge. Full colour night photos obtained LED illumination reaches 30 m (3 MP standard image resolution). Images recorded every 15 min December 2020 July 2022 (the requiring only monthly battery changes). nearly 58 000 assembled form single motion picture. An accelerated playback video shows events took place slowly riparian zone. first sequence, display high-speed aggregate taken noon 20 months. second sequence aggregated pictures min, slower rendering various parallel independently (Table 1). Both videos are accompanied graphs hourly precipitation (mm/h), air temperature (°C), global radiation (W/m2), stem radial growth (increase maximum radius, μm), deficit (deviations past moisture (volumetric percent 10, 20, 40 60 cm depths), groundwater level zone (m), stage (cm). horizontal series plot above displays recordings moisture, levels, precipitation, moving marker indicating position current frame. On right, three additional plots detailed diurnal variations selected variables 5 days before after These include (top), (middle), ground-water level, (bottom). vertical axes span minimum each series, whereas actual values corresponding frame shown legend box placed top right video. [00:17] [01:17] 12th March 2021 [07:48] 20th [08:19] 14th [16:02] 15th [16:08] 07th June [13:36] 27th [14:55] May [12:52] [13:35] 10th [38:07] [38:46] April [10:03] 30th [11:02] 5th January [03:24] [04:23] 7th February [05:36] [06:07] Below, refer scenes sub-scenes exemplify They identified their stamps, which can be easily accessed clicking chapters description available https://youtu.be/74S7DfT7Uhs. Note all described detail contribution. Our selection guided following criteria: (i) wetness state catchment, expressed through periods, (ii) representativeness knowledge gained prior research (iii) genuine original character observations. [start 00:17–end 01:17] reveals comprehensive winter, spring, autumn seasons cohort gradually feedback mechanisms (Figure temperatures below zero several snowfall events—triggering slow gradual snow-fed recharge (recorded probes wells). Balmy weather spring comes onset leaf sprout recession levels hydrographs. summer, most dynamic (exhibiting signals almost growth), while discharge along successive wet sequences. With cooler autumn, abscission commences, enters dormant season, system switches rain-fed state. 20-months long seasonal pulse representative two decades environmental catchment. network 36 wells seven piezometers creek across conditions (Bonanno contrasting responses rainfall dry, intermediate, controlled decrease capacity fractured bedrock and/or saprolite depth (with roles intensity). During August September 00:40–end 00:47], 01:14–end 01:17]), low, direction typically large anisotropy hydraulic conductivity characterizes bedrock. increasing wetness, near-stream rise, directions competing influence upslope-footslope connectivity streamwater 00:37–end 00:40]). November 00:49–end 00:53]), when hillslope-stream restored, hyporheic compressed movement hillslope stream, advection in-stream turbulences become primary controlling channel 2022, 2023). observed exchange adjacent significant implications solute nutrient transport reach Leaf October 00:46–end 00:49]) subsequent litter degradation significantly contribute stock nutrients trees regulated biotic abiotic factors—such community decomposing organisms, incident light, (Montemagno 2022; Tagliavini 2007). sub-scene 2.1.a, spanning 07:48–end 08:19], perfect illustration occurrence double-peak hydrograph 2). peak (loaded sediment inferred brownish water) coincides event, hours even later broader, delayed negligible load, suggested now transparent observed. Double hydrographs regularly occur conditions, reached threshold required upslope locations. behaviour apparent simultaneous (Martínez-Carreras, Hissler, 2016). double hydrographs, increases subsequently leads Single quickly flowing pulses. 2.1.b, 16:02–end 16:08], nicely illustrates mainly occurs peaks, mobilization bed sediments originating highly enriched organic matter Schwab, Suspended concentrations much lower peaks because they dominated contributions groundwater. Time-lapse photography suggests images infer suspended surface, recently Ghorbani al. (2020). Along similar lines, may inform changes content) origin Martínez-Carreras 2010) runoff events. frequently undergoes phases pronounced runs dry. extreme links discharge, signals, uptake, clearly 3). As 2.2.a (7th 13:36–end 14:55]), daily minima afternoon evapotranspiration—also recordings. Even occurred growing season diel fluctuations table beneath streambed 38:47–end 41:10]. linked uptake vegetation, consisting 2021): alders—a species thrives areas—and beeches domain. result, certain sections undergo transitions gaining losing relation groundwater, depending antecedent evapotranspiration Diel many streams attributed cycle (Wondzell rhythmic movements herbaceous plants (sub-scene 2.2.b, 12:52–end 13:35]), unlikely triggered drivers consistent circadian driven internal, genetic clock documented plant (Müller Jiménez-Gómez, exception lowering leaves 22nd 7:30 onwards obviously wind blasts, kinetic energy precipitation). very thickness, late maxima stress (Zweifel Häsler, 2001). sunflecks forest floor 2.2.c, 38:07–end 38:46]) example exposition sudden heat (Schymanski 2013). Diurnal budget patterns trees. (μm) (TWD) spruce located monitored using band dendrometer. TWD, i.e., difference radius full hydration (Zweifel, 2016), day 14:55]) progressive depletion elastic tissues (Dietrich 2018). When transpiration ceases night, rehydration due root causes re-expansion diameter TWD decreases. fluctuation content (Fabiani 2022) confirms relevance storage, mediates demand availability. periods day-time 2.2.d, 10:03–end 11:02]), opposed active 4). signal explained upper layer (Schwab day, higher eventually warms water, turn reduction viscosity increase conductivity. sometimes result effects instrumentation, evidence here thus helps eliminate false interpretation fluctuating data. months, times prolonged below-freezing ground temperatures, swelling. needle ice formed soft 2.3.a, 03:24–end 04:23], 2.3.b 05:36–end 06:07]). cold spells, recessions 5). Because formation, soils rise 10 cm. phenomenon forming drawn pores, requires specific texture well (Outcalt, 1971). Needle forms surface disturbs it, greatly availability fluvial (Lawler, 1993) potentially uprooting 1988). decades, undergoing extensive campaigns, alongside high-resolution sensing programmes. Altogether, these initiatives contributed substantially improve involved Weierbach's fundamental functions collection, mixing release. improved step perceptual model catchment's modus operandi Hissler Martínez-Carreras, 2016; Wrede 2015) associated co-evolve seasons, into longer spans climate change), fragmented. other words, adding arranging puzzle pieces, found picture than anticipated. Consequently, do yet fully-fledged simulate manifold factors work. sensors provide information cessation processes, lack importance. thousands min—spanning contrasted states—provides entirely new vistas respect. Certain visible otherwise overlooked, especially set (and operated Therefore, alternative starting hypothesis framing testing. freeze–thaw telling regard, demonstrating cameras deployed complement sensors, (largely underrated underused) scientists' human sensory cognitive aptitudes (Van Stan Finally, useful checking sensor readings validation process combination four-season-long multi-parameter dataset offering perspective 'bringing it together' 2005)—providing innovative opportunity combining 'soft' 'hard' improving dialogue hydrologists ecophysiologists (Cocozza Penna, 2022), experimentalists modellers (Seibert McDonnell, 2002). plan continue years, believe headwater 'terminus quo' 'catchment framing'—as achieved via geomorphological biota, anthropogenic activities management). findings pave way plasticity optimality-based models evolution dynamics. latter considering accounting intrinsic non-stationary (or non-rigid) catchments—as prerequisite reducing uncertainties assessment changed climate. support openly Experimental Catchment (WEC) https://doi.org/10.5281/zenodo.4537700.

Язык: Английский

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Allometric relations between DBH and sapwood area for predicting stand transpiration: lessons learned from the Quercus genus

European Journal of Forest Research, Год журнала: 2023, Номер 142(4), С. 797 - 809

Опубликована: Март 29, 2023

Abstract Catchment-scale transpiration is commonly determined by the use of sap-flow sensors, and its quantification, which critical for water forest management, relies crucially on total catchment’s sapwood area ( A s ). Species-specific allometric relationships between trees diameter at breast height (DBH) are widely used determining stand or catchment . However, substantial differences studies challenge robustness these sites displaying various topographical environmental characteristics. Our objectives this study to compare parameters species Quercus genus from different across globe test role factors -DBH relationship in petraea Using 145 sampled within a 0.455 km 2 catchment, we found that topography (slope, flow accumulation, aspect, curvature, topographic wetness index) does not modulate Q. , our catchment. We compared curve with those 16 oak only species-specific, but depends site’s conditions. The species-specific other may lead more than 100% difference calculation therefore transpiration. In light results, recommend building site- transpiration, using minimum nine, randomly trees, methods azimuthal directions depth.

Язык: Английский

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