Soil affects throughfall and stemflow under Turkey oak (Quercus cerris L.)

Rainfall is one of the primary sources of chemical inputs in forest ecosystems, and the basis of forest nutrient cycling. Mixed evergreen and deciduous broadleaved forests are currently one of the most threatened ecosystems due to their sensitivity to anthropogenic climate change. As such, understanding the hydrochemical fluxes of these systems is critical for managing their dynamics in the future. We investigate the chemistry of bulk precipitation, stemflow and throughfall in a mixed evergreen and deciduous broadleaved forest in the Shennongjia region of Central China. Mean nutrient concentrations in throughfall and stemflow were higher than in bulk precipitation. Stemflow ion fluxes from deciduous tree species were greater than those for evergreen tree species because of the differences in bark morphology and branch architecture. Throughfall and stemflow chemistry fluctuated dramatically over the growing season. Nitrate nitrogen and ammonium nitrogen were retained, while other elements and compounds were washed off or leached via throughfall and stemflow pathways. Our findings will facilitate a greater understanding of nutrient balance in canopy water fluxes.

Section: Discussionmentioning

confidence: 99%

Hydrochemical Fluxes in Bulk Precipitation, Throughfall, and Stemflow in a Mixed Evergreen and Deciduous Broadleaved Forest

Zhao

et al. 2019

“…By comparison, our annual K + , Na + and Mg 2+ fluxes were relatively lower, and the Ca 2+ flux was higher than that in the other studies. The differences in stemflow base cation flux were attributed to many factors, such as geographic location, atmospheric environment, stand density, soil properties and tree species composition [14,30,31]. High atmospheric deposition in the rainy zone of western China [32] increased base cation deposition into stemflow, especially for Ca 2+ , whose wet deposition reached 102 kg ha −1 year −1 in our study.…”

Section: Discussionmentioning

confidence: 51%

Base Cation Fluxes from the Stemflow in Three Mixed Plantations in the Rainy Zone of Western China

Liu

Jiang

You

et al. 2019

Base cation transfer from stemflow is an important process for nutrient transfer and plays a key role in maintaining the balance of soil nutrient pools. To research the differences of stemflow chemistry in mixed plantations, we conducted a continuous field experiment in the rainy zone of Western China from December 2016 to November 2017. Three representative mixed plantations, including a conifer–broadleaved mixed plantation, a deciduous broadleaved mixed plantation and a multispecies mixed plantation, were selected to investigate the concentration and flux characteristics of K+, Na+, Ca2+ and Mg2+ in stemflow. The results showed that: (1) the K+, Na+, Ca2+ and Mg2+ fluxes ranged from 1.75 to 2.44 kg ha−1 year−1, 0.14 to 0.24 kg ha−1 year−1, 1.25 to 2.11 kg ha−1 year−1, and 0.40 to 0.60 kg ha−1 year−1 in these mixed plantations during the one-year observation, and the annual or seasonal (i.e., rainy or dry season) base cation fluxes in the stemflow varied slightly with the plantation types; (2) broadleaved trees had a higher average stemflow base cation contribution rate and flux-based enrichment ratio than coniferous trees, and the enrichment ratios showed a decreasing tendency with increasing trunk diameter; (3) the stemflow base cation concentration was higher in the dry season, while flux was observed to be higher in the rainy season. These results suggested that increasing the proportion of broadleaved species in mixed plantations might improve soil nutrient content and benefit material cycling in subtropical forest ecosystems.

“…Stemflow modifications of inorganic nitrogen exhibited the opposite seasonal trend as throughfall. For NO 3 − , stemflow enrichment was greater under leafed conditions compared to leafless conditions, and for NH 4 + , enrichment in stemflow was greater under leafless conditions and less than one under leafed conditions, except for Shagbark hickory (Table 2). Shagbark hickory enrichment of both forms of inorganic nitrogen was substantially larger than all other species, regardless of season (Figure 4d,f and Table 2).…”

Section: Throughfall and Stemflow Inorganic Nitrogen Enrichmentmentioning

confidence: 98%

“…Oaks (Quercus) are a dominant overstory species in many upland forest ecosystems across the eastern United States that contribute vital ecosystem services through water and nutrient cycling [1][2][3][4][5]. Given the prevalence, longevity, and diversity of oak species in forest ecosystems, it is likely that these species strongly mediate nutrient cycling when present [6][7][8].…”

Section: Introductionmentioning

confidence: 99%

Interspecific Differences in Canopy-Derived Water, Carbon, and Nitrogen in Upland Oak-Hickory Forest

Limpert

Siegert

2019

Oaks (Quercus) are a dominant forest species throughout much of the eastern United States. However, oak regeneration failure due to a myriad of issues (e.g., suppression of natural fire, excess nitrogen deposition, pressure from herbivore activity) is leading to a decline in oak dominance. This change may alter forest hydrology and nutrients through variation in species characteristics. Throughfall (TF) and stemflow (SF) quantity and chemistry were sampled during storm events under oak and non-oak (hickory, Carya) species to quantify differences in canopy-derived water and nutrients from an upland oak-hickory forest in Mississippi. Stemflow partitioning was 86% higher in hickory species compared to oak species (394.50 L m−2; p < 0.001). Across all species, dissolved organic carbon (DOC) was 1.5 times greater in throughfall (p = 0.024) and 8.7 times greater in stemflow (p < 0.001) compared to rainfall. White oak DOC concentrations (TF: 22.8 ± 5.5 mg L−1; SF: 75.1 ± 9.5 mg L−1) were greater compared to hickory species (TF: 21.0 ± 18.3 mg L−1; SF: 34.5 ± 21.0 mg L−1) (p = 0.048). Results show that while smoother-barked hickory species generate more stemflow volume, rougher-barked oak species generate stemflow that is more enriched in nutrients, which is a function of the canopy characteristics of each species. Within a single stand, this study demonstrates how variable water and nutrient fluxes may be and provide insights into species-level variability in oak-hickory forest types that may be undergoing compositional changes.