Tree Species Composition Influences Enzyme Activities and Microbial Biomass in the Rhizosphere: A Rhizobox Approach

Afforestation with pure and mixed-species is an important strategy to improve soil organic carbon (SOC) stocks and restore degraded lands. However, what remains unclear is the stability of SOC to microbial degradation after afforestation and the effect of tree species composition. Moreover, it is important to reveal how sensitive the SOC in afforestation lands is to environmental changes, such as warming. To study the combined effects of warming and the tree species composition on decomposition of SOC by microorganisms and enzyme activities, soils were collected from the monocultural and mixtures of Silver birch (Betula Pendula) and European beech (Fagus Silvatica) (BangorDiversity, UK, 12 years since afforestation) and were incubated for 169 days at 0, 10, 20, 30 &#176;C at 60 % of WHC. The field experiment is arranged into a completely randomized design with n=4. The CO2 efflux was measured constantly, whereas activities of &#946;-glucosidase, chitinase and acid phosphatase, and content of microbial biomass C (MBC) were obtained at the end of the incubation.&#160;Results showed that soil cumulative CO2 efflux increased by 34.7&#8211;107% with the temperature. Potential enzyme activities were dependent on tree species composition. Warming, but not tree species exhibited a significant impact on the temperature sensitivity (Q10) of soil cumulative CO2 efflux and enzyme activities. The greatest temperature sensitivity (Q10) of total CO2 efflux was found at 10&#8211;20 &#176;C and was 2.0&#8211;2.1, but that of enzyme activities were found as 0.9&#8211;1.1 at 0&#8211;10 &#176;C. These results suggest that warming has an asynchronous effect on the SOC decomposition and enzyme activity, and enzymes cannot account for the temperature sensitivity of soil respiration. Thus, thermal adaptations of SOC mineralization is independent of the adaptation of the enzyme pool.

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Langfristige Entwicklung von zwei Waldgesellschaften im Białowieża-Urwald

Schweizerische Zeitschrift fur Forstwesen ◽

10.3188/szf.2008.0080 ◽

2008 ◽

Vol 159 (4) ◽

pp. 80-90 ◽

Cited By ~ 3

Author(s):

Bogdan Brzeziecki ◽

Feliks Eugeniusz Bernadzki

Keyword(s):

Species Composition ◽

Tree Species ◽

Stand Structure ◽

Temporal Dynamics ◽

Structural Parameters ◽

Forest Communities ◽

Natural Forests ◽

Tree Species Composition ◽

Strong Trend ◽

Long Term Study

The results of a long-term study on the natural forest dynamics of two forest communities on one sample plot within the Białowieża National Park in Poland are presented. The two investigated forest communities consist of the Pino-Quercetum and the Tilio-Carpinetum type with the major tree species Pinus sylvestris, Picea abies, Betula sp., Quercus robur, Tilia cordata and Carpinus betulus. The results reveal strong temporal dynamics of both forest communities since 1936 in terms of tree species composition and of general stand structure. The four major tree species Scots pine, birch, English oak and Norway spruce, which were dominant until 1936, have gradually been replaced by lime and hornbeam. At the same time, the analysis of structural parameters indicates a strong trend towards a homogenization of the vertical stand structure. Possible causes for these dynamics may be changes in sylviculture, climate change and atmospheric deposition. Based on the altered tree species composition it can be concluded that a simple ≪copying≫ (mimicking) of the processes taking place in natural forests may not guarantee the conservation of the multifunctional character of the respective forests.

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Effects of nitrogen deposition on nitrate leaching from forests of the northeastern United States will change with tree species composition

Canadian Journal of Forest Research ◽

10.1139/cjfr-2016-0529 ◽

2017 ◽

Vol 47 (8) ◽

pp. 997-1009 ◽

Cited By ~ 5

Author(s):

Katherine F. Crowley ◽

Gary M. Lovett

Keyword(s):

United States ◽

Species Composition ◽

Nitrate Leaching ◽

Tree Species ◽

N Deposition ◽

Red Oak ◽

Northeastern United States ◽

Tree Species Composition ◽

White Ash ◽

Species Change

As tree species composition in forests of the northeastern United States changes due to invasive forest pests, climate change, or other stressors, the extent to which forests will retain or release N from atmospheric deposition remains uncertain. We used a species-specific, dynamic forest ecosystem model (Spe-CN) to investigate how nitrate (NO3–) leaching may vary among stands dominated by different species, receiving varied atmospheric N inputs, or undergoing species change due to an invasive forest pest (emerald ash borer; EAB). In model simulations, NO3– leaching varied widely among stands dominated by 12 northeastern North American tree species. Nitrate leaching increased with N deposition or forest age, generally with greater magnitude for deciduous (except red oak) than coniferous species. Species with lowest baseline leaching rates (e.g., red spruce, eastern hemlock, red oak) showed threshold responses to N deposition. EAB effects on leaching depended on the species replacing white ash: after 100 years, predicted leaching increased 73% if sugar maple replaced ash but decreased 55% if red oak replaced ash. This analysis suggests that the effects of tree species change on NO3– leaching over time may be large and variable and should be incorporated into predictions of effects of N deposition on leaching from forested landscapes.

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