scholarly journals 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 ◽  
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.

scholarly journals A Method for Performing Reforestation to Effectively Recover Soil Water Content in Extremely Degraded Tropical Rain Forests

2021 ◽  
Vol 9 ◽  
Author(s):  
Tiedong Liu ◽  
Kai Jiang ◽  
Zhaoyuan Tan ◽  
Qifang He ◽  
Hui Zhang ◽  
...  
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Effective Means ◽  
Tropical Rain Forests ◽  
Rain Forests ◽  
Simple Method ◽  
Fast Growing ◽  
Slow Growing ◽  
Fast Growing Species

Deforestation continues to be extensive in the tropics, resulting in reduced soil water content. Reforestation is an effective way to recover soil water content, but the recovery depends on the type of reforestation efforts that are implemented. Monoculture of fast-growing species is a common reforestation strategy, because it is an effective means of preventing landslides resulting from the frequent typhoons and heavy rains in the tropics and easy to implement. To quantify whether monoculture plantings can help recover soil water content, we initiated a reforestation project within a 0.2 km2 area of an extremely degraded tropical monsoon forest. We hypothesized that much higher transpiration rate of fast-growing tree species would deplete soil water more than the dominant slow-growing species in the adjacent secondary tropical rain forest during both wet and dry seasons, thereby resulting in much lower soil water content. To test this hypothesis, we compared transpiration rates and key functional traits that can distinguish transpiration rates between fast-growing and dominant slow-growing species in both wet and dry seasons. We also quantified whether soil water content around these species differed. We found that fast-growing species had transpiration rate and transpiration-related trait values that were 5–10 times greater than the dominant slow-growing species in both seasons. We also found that soil water content around dominant slow-growing species was 1.5–3 times greater than for fast-growing species in both seasons. Therefore, reforestation based on monoculture plantings of fast-growing species seems difficult to effectively recover the soil water content. We also provide a simple method for guiding the use of reforestation efforts to recover soil water content in extremely degraded tropical rain forests. We expect that this simple method can be an effective means to restore extremely degraded tropical rain forests in other parts of the world.

scholarly journals Relationship between Very Fine Root Distribution and Soil Water Content in Pre- and Post-Harvest Areas of Two Coniferous Tree Species

Forests ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 1227
Author(s):  
Moein Farahnak ◽  
Keiji Mitsuyasu ◽  
Takuo Hishi ◽  
Ayumi Katayama ◽  
Masaaki Chiwa ◽  
...  
Keyword(s):  
Water Content ◽  
Root System ◽  
Soil Water ◽  
Soil Water Content ◽  
Tree Species ◽  
Fine Roots ◽  
Fine Root ◽  
Soil Depth ◽  
Tree Cutting ◽  
Coniferous Tree Species

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.

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

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.

scholarly journals Tropical Rainforest Successional Processes can Facilitate Successfully Recovery of Extremely Degraded Tropical Forest Ecosystems Following Intensive Mining Operations

2021 ◽  
Vol 9 ◽  
Author(s):  
Yang Zhao ◽  
Yike Zou ◽  
Lu Wang ◽  
Rui Su ◽  
Qifang He ◽  
...  
Keyword(s):  
Tropical Forest ◽  
Soil Water ◽  
Tree Species ◽  
Tropical Rainforest ◽  
Nutrient Loss ◽  
Bare Rock ◽  
Soil Layers ◽  
Fast Growing ◽  
Tropical Tree Species ◽  
Plant Life

Reforestation is an effective way to alleviate deforestation and its negative impacts on ecosystem services. In tropical rainforest ecosystem, however, frequent typhoons and heavy rainfall can result in landslides and uprooting of many seedlings, making reforestation efforts very difficult, especially within extremely degraded sites where soil conditions cannot support any plant life. Here, we described a reforestation protocol which is based on tropical rainforest successional processes to not only prevent landslides and tree uprooting due to frequent typhoon and heavy rain, but also accelerate tropical forest succession. This protocol first used the slope and soil layer of the undisturbed old-growth tropical rainforest as a reference to reconstruct slope and soil layers. Then multiple tropical tree species with high growth and survival rate were separately monocultured in the reconstructed soil layers. In the year of 2015 and 2016, we tested the effectiveness of this protocol to recover a 0.2 km2 extremely degraded tropical rainforest which consists of bare rock and thus does not support any plant life, in Sanya city, China. Our results showed that, both typhoons and heavy rains did not result in landslide or any tree damages in the area this reforestation protocol was used. Moreover, our separately monocultured eight fast-growing tree species have much higher fast-growing related functional traits than those for tree species in the adjacent undisturbed tropical seasonal forest, which in turn resulted in large soil water and nutrient loss within 3 years. This seemed to simulate a quick transition from primary succession (consist of bare rock and cannot support any plant life) to mid-stage of secondary tropical rainforest succession (many fast-growing pioneer tree species induced high soil water and nutrient loss). Thus, mixing the late-successional tropical tree species with each of the separately monocultured eight fast-growing tree species can accelerate recovery to the undisturbed tropical rainforest as soon as possible. Overall, based on tropical rainforest successional processes, our research provides an effective protocol for quickly and effectively restoring an extremely degraded tropical rainforest ecosystem. We expect that this work will be important for the future recovery of other extremely degraded tropical rainforest ecosystems.

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

2008 ◽  
Vol 38 (3) ◽  
pp. 528-538 ◽  
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.

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

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.

SOIL WATER CONTENT AFFECTS THE AVAILABILITY OF PHOSPHATE

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.

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

2010 ◽  
Vol 59 (1) ◽  
pp. 157-164 ◽  
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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