Leaf Anatomical Acclimation of Six Tree Species to Low Soil Water Content

Tree root system development alters forest soil properties, and differences in root diameter frequency and root length per soil volume reflect differences in root system function. In this study, the relationship between vertical distribution of very fine root and soil water content was investigated in intact tree and cut tree areas. The vertical distribution of root density with different diameter classes (very fine <0.5 mm and fine 0.5–2.0 mm) and soil water content were examined along a slope with two coniferous tree species, Cryptomeria japonica (L.f.) D. Don and Chamaecyparis obtusa (Siebold et Zucc.) Endl. The root biomass and length density of very fine roots at soil depth of 0–5 cm were higher in the Ch. obtusa intact tree plot than in the Cr. japonica intact plot. Tree cutting caused a reduction in the biomass and length of very fine roots at 0–5 cm soil depth, and an increment in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot one year after cutting. However, very fine root density of the Cr. japonica intact tree plot was quite low and the soil water content in post-harvest areas did not change. The increase in soil water content at 5–30 cm soil depth of the Ch. obtusa cut tree plot could be caused by the decrease in very fine roots at 0–5 cm soil depth. These results suggest that the distribution of soil water content was changed after tree cutting of Ch. obtusa by the channels generated by the decay of very fine roots. It was also shown that differences in root system characteristics among different tree species affect soil water properties after cutting.

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Physiological and climate controls on foliar mercury uptake by European tree species

10.5194/bg-2021-239 ◽

2021 ◽

Author(s):

Lena Wohlgemuth ◽

Pasi Rautio ◽

Bernd Ahrends ◽

Alexander Russ ◽

Lars Vesterdal ◽

...

Keyword(s):

Stomatal Conductance ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Tree Species ◽

Physiological Activity ◽

Growing Season ◽

Relevant Parameter ◽

Uptake Rates ◽

Mercury Uptake

Abstract. Despite the importance of vegetation uptake of atmospheric gaseous elemental mercury (Hg(0)) within the global Hg cycle, little knowledge exists on the physiological, climatic and geographic factors controlling stomatal uptake of atmospheric Hg(0) by tree foliage. We investigate controls on foliar stomatal Hg(0) uptake by combining Hg measurements of 3,569 foliage samples across Europe with data on tree species traits and environmental conditions. To account for foliar Hg accumulation over time, we normalized foliar Hg concentration over the foliar life period from the simulated start of the growing season to sample harvest. The most relevant parameter impacting daily foliar stomatal Hg uptake was tree functional group (deciduous versus coniferous trees). On average, we measured 3.2 times higher daily foliar stomatal Hg uptake rates in deciduous leaves than in coniferous needles of the same age. Across tree species, for foliage of beech and fir, and at two out of three forest plots with more than 20 samples, we found a significant (p < 0.001) increase in foliar Hg values with respective leaf nitrogen concentrations. We therefore suggest, that foliar stomatal Hg uptake is controlled by tree functional traits with uptake rates increasing from low to high nutrient content representing low to high physiological activity. For pine and spruce needles, we detected a significant linear decrease of daily foliar stomatal Hg uptake with the proportion of time, during which vapor pressure deficit (VPD) exceeded the species-specific threshold values of 1.2 kPa and 3 kPa, respectively. The proportion of time within the growing season, during which surface soil water content (ERA5-Land) in the region of forest plots was low correlated negatively with corresponding foliar Hg uptake rates of beech and pine. These findings suggest that stomatal uptake of atmospheric Hg(0) is inhibited under high VPD conditions and/or low soil water content due the regulation of stomatal conductance to reduce water loss under dry conditions. We therefore propose, that foliar Hg measurements bear the potential to serve as proxy for stomatal conductance. Other parameters associated with forest sampling sites (latitude and altitude), sampled trees (average age and diameter at breast height) or regional satellite observation-based transpiration product (GLEAM) did not significantly correlate with daily foliar Hg uptake rates. We conclude that tree physiological activity and stomatal response to VPD and soil water content should be implemented in a stomatal Hg model, to assess future Hg cycling under different anthropogenic emission scenarios and global warming.

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Interactive effects of soil water content and nutrients on root exudation in two Mediterranean tree species

Soil Biology and Biochemistry ◽

10.1016/j.soilbio.2021.108453 ◽

2021 ◽

pp. 108453

Author(s):

Catherine Preece ◽

Gerard Farré-Armengol ◽

Erik Verbruggen ◽

Josep Peñuelas

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Tree Species ◽

Root Exudation ◽

Interactive Effects

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Tree species mediated effects on leaf litter dynamics in pure and mixed stands of oak and beech

Canadian Journal of Forest Research ◽

10.1139/x07-183 ◽

2008 ◽

Vol 38 (3) ◽

pp. 528-538 ◽

Cited By ~ 30

Author(s):

Mathieu Jonard ◽

Frederic Andre ◽

Quentin Ponette

Keyword(s):

Mass Loss ◽

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Leaf Litter ◽

Tree Species ◽

Litter Quality ◽

Leaf Decomposition ◽

Mixed Stands ◽

Stand Type

This study aimed to evaluate the relative importance of the factors whereby tree species composition can influence leaf litter dynamics. Leaf litter production and chemical composition were measured in pure and mixed stands of oak ( Quercus petraea Liebl.) and beech ( Fagus sylvatica L.). Pure and mixed leaf litter of both species were incubated in each stand type to assess separately the environmental, litter quality, and litter mixture effects on decomposition. To better understand the environmental effects, ground climate was measured in the different stands and the effects of soil water content on decomposition were evaluated using roofs to simulate drought conditions. Although total leaf litter amounts were not affected by stand composition, leaf decomposition varied with litter quality and with the environmental conditions. In the same environment, oak leaf litter disappeared on average 1.7 times faster than beech leaf litter. Decomposition of oak leaves increased significantly in the mixed-species litterbags. In contrast, the overall mass loss of the mixed litter tallied with the mass loss estimated by examining the decomposition of the component litter separately (additive-effect hypothesis). The effects of stand type appeared in the third year of incubation: leaf mass loss of both species was greater in the beech stand. In addition, soil water content affected leaf decomposition: the oak and beach leaf mass losses dropped by 24% and 17%, respectively, in the dry modality.

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Biotic and abiotic drivers of soil microbial functions across tree diversity experiments

10.1101/2020.01.30.927277 ◽

2020 ◽

Author(s):

Simone Cesarz ◽

Dylan Craven ◽

Harald Auge ◽

Helge Bruelheide ◽

Bastien Castagneyrol ◽

...

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Tree Species ◽

Soil Microorganisms ◽

Tree Diversity ◽

Soil Microbial ◽

Context Dependent ◽

Diversity Effects ◽

High Tree Density

AbstractAimSoil microorganisms are essential for the functioning of terrestrial ecosystems. Although soil microbial communities and functions may be linked to the tree species composition and diversity of forests, there has been no comprehensive study of how general potential relationships are and if these are context-dependent. A global network of tree diversity experiments (TreeDivNet) allows for a first examination of tree diversity-soil microbial function relationships across environmental gradients.LocationGlobalMajor Taxa StudiedSoil microorganismsMethodsSoil samples collected from eleven tree diversity experiments in four biomes across four continents were used to measure soil basal respiration, microbial biomass, and carbon use efficiency using the substrate-induced respiration method. All samples were measured using the same analytical device in the same laboratory to prevent measurement bias. We used linear mixed-effects models to examine the effects of tree species diversity, environmental conditions, and their interactions on soil microbial functions.ResultsAcross biodiversity experiments, abiotic drivers, mainly soil water content, significantly increased soil microbial functions. Potential evapotranspiration (PET) increased, whereas soil C-to-N ratio (CN) decreased soil microbial functions under dry soil conditions, but high soil water content reduced the importance of other abiotic drivers. Tree species richness and phylogenetic diversity had overall similar, but weak and context-dependent (climate, soil abiotic variables) effects on soil microbial respiration. Positive tree diversity effects on soil microbial respiration were most pronounced at low PET, low soil CN, and high tree density. Soil microbial functions increased with the age of the experiment.Main conclusionsOur results point at the importance of soil water content for maintaining high levels of soil microbial functions and modulating effects of other environmental drivers. Moreover, overall tree diversity effects on soil microbial functions seem to be negligible in the short term (experiments were 1-18 years old). However, context-dependent tree diversity effects (climate, soil abiotic variables) have greater importance at high tree density, and significant effects of experimental age call for longer-term studies. Such systematic insights are key to better integrate soil carbon dynamics into the management of afforestation projects across environmental contexts, as today’s reforestation efforts remain focused largely on aboveground carbon storage and are still dominated by less diverse forests stands of commercial species.

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Reforestation Based on Mono-Plantation of Fast-Growing Tree Species Make It Difficult to Maintain (High) Soil Water Content in Tropics, a Case Study in Hainan Island, China

Water ◽

10.3390/w12113077 ◽

2020 ◽

Vol 12 (11) ◽

pp. 3077

Author(s):

Wenjun Hong ◽

Jindian Yang ◽

Jinhuan Luo ◽

Kai Jiang ◽

Junze Xu ◽

...

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Tree Species ◽

Tropical Rainforest ◽

High Growth ◽

Fast Growing ◽

Dry Seasons ◽

Very High ◽

Fast Growing Species

Reforestation has been assumed as a natural solution to recover soil water content, thereby increasing freshwater supply. Mono-plantation of fast-growing species is the first step for performing reforestation to prevent frequent and heavy rain-induced landslide in tropics. However, fast-growing species may have negative hydraulic response to seasonal drought to maintain high growth rate and, thus, may make it difficult for reforestation in tropics to recover soil water content. We tested this hypothesis in a setting involving (a) a reforestation project, which mono-planted eight fast-growing tree species to successfully restore a 0.2-km2 extremely degraded tropical rainforest, and (b) its adjacent undisturbed tropical rainforest in Sanya City, Hainan, China. We found that, for maintaining invariably high growth rates across wet to dry seasons, the eight mono-planted fast-growing tree species had comparable transpiration rates and very high soil water uptake, which in turn led to a large (3 times) reduction in soil water content from the wet to dry seasons in this reforested area. Moreover, soil water content for the adjacent undisturbed tropical rainforest was much higher (1.5 to 5 times) than that for the reforested area in both wet and dry seasons. Thus, the invariably very high water demand from the wet to dry seasons for the mono-planted fast-growing species possesses difficulty in the recovery of soil water content. We suggest, in the next step, to mix many native-species along with the currently planted fast-growing nonnative species in this reforestation project to recover soil water content.

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SOIL WATER CONTENT AFFECTS THE AVAILABILITY OF PHOSPHATE

Proceedings of the New Zealand Grassland Association ◽

10.33584/jnzg.1985.46.1696 ◽

1985 ◽

pp. 185-189

Author(s):

M.C.H.Mouat Pieter Nes

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Soil Solution ◽

Equivalent Reduction

Reduction in water content of a soil increased the concentration of ammonium and nitrate in solution, but had no effect on the concentration of phosphate. The corresponding reduction in the quantity of phosphate in solution caused an equivalent reduction in the response of ryegrass to applied phosphate. Keywords: soil solution, soil water content, phosphate, ryegrass, nutrition.

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Effect of inter-row cultivation on soil carbon dioxide emission in a peach plantation

Agrokémia és Talajtan ◽

10.1556/agrokem.59.2010.1.19 ◽

2010 ◽

Vol 59 (1) ◽

pp. 157-164 ◽

Cited By ~ 1

Author(s):

E. Tóth ◽

Cs. Farkas

Keyword(s):

Water Content ◽

Soil Water ◽

Soil Water Content ◽

Carbon Dioxide Emission ◽

Nutrient Content ◽

Soil Disturbance ◽

Biological Properties ◽

Soil Tillage ◽

Favourable Effect ◽

Volumetric Soil Water Content

Soil biological properties and CO2emission were compared in undisturbed grass and regularly disked rows of a peach plantation. Higher nutrient content and biological activity were found in the undisturbed, grass-covered rows. Significantly higher CO2fluxes were measured in this treatment at almost all the measurement times, in all the soil water content ranges, except the one in which the volumetric soil water content was higher than 45%. The obtained results indicated that in addition to the favourable effect of soil tillage on soil aeration, regular soil disturbance reduces soil microbial activity and soil CO2emission.

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