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The process-based biogeochemical model Biome-BGC was enhanced to improve its ability to simulate carbon, nitrogen, and water cycles of various terrestrial ecosystems under contrasting management activities. Biome-BGC version 4.1.1 was used as a base model. Improvements included addition of new modules such as the multilayer soil module, implementation of processes related to soil moisture and nitrogen balance, soil-moisture-related plant senescence, and phenological development. Vegetation management modules with annually varying options were also implemented to simulate management practices of grasslands (mowing, grazing), croplands (ploughing, fertilizer application, planting, harvesting), and forests (thinning). New carbon and nitrogen pools have been defined to simulate yield and soft stem development of herbaceous ecosystems. The model version containing all developments is referred to as Biome-BGCMuSo (Biome-BGC with multilayer soil module; in this paper, Biome-BGCMuSo v4.0 is documented).Case studies on a managed forest, cropland, and grassland are presented to demonstrate the effect of model developments on the simulation of plant growth as well as on carbon and water balance. [ABSTRACT FROM AUTHOR]

Supported by the rapidly increasing global trade and the climate change, alien and invasivespecies are appearing at an alarming rate throughout the World, causing unexpecteddisturbances to the forests, and frequently resulting in significant economic losses. The oaklace bug (Corythucha arcuata, Say 1832), native to North America, is a new invasive speciesin Central Europe, spreading rapidly and causing damage on foliage, primarily of oak trees,potentially jeopardizing the long term health and stability of natural oak forests. Since it wasfirst recorded in Northern Italy in 2000, the spread and the magnitude of the oak lace buginfestation has gained momentum, now noticeably affecting - among many other regions - thevaluable pedunculate oak forests of the Pannonian Plain. Damage to the leavescaused by the oak lace bug, as a result of leaf-sucking, affects leaf photosynthesisnegatively. Damage (early discoloration) becomes particularly pronounced in the secondpart of the vegetation season and could be observed and quantified by means ofsatellite remote sensing, such as using Normalized Difference Vegetation Index(NDVI). In the present study we used C006 MOD09 and MOD13 NDVI time-series of theMODerate resolution Imaging Spectroradiometer (MODIS) with the finest 250 m spatialresolution to detect, both at temporal and spatial scale, and to quantify the damage caused bythe oak lace bugs in larger oak stands in the Pannonian Plain. The results demonstrate, in eachyear starting from 2016, a remarkable NDVI decline in the oak forests of the Spačva Basin(located in eastern part of Croatia and western part of Serbia), showing a 0.15 negativeNDVI anomaly relative to the multiannual mean values for at least 2 months long during theperiod of August-October. The timing of the significant NDVI decrease seems to beaffected by the weather conditions, too. Field observations (tree cores) providedbackground information on the effects of the high population density of oak lace bugs inthe Slavonian forests of the Spačva Basin. Data of the MultiSpectral Instrument(MSI) onboard the recently launched European Sentinel-2A/2B satellites was alsoinvestigated for the applicability of detecting the damage caused by the oak lace bugs,however due to their recent launch time, their measurements still do not provide a longenough archive dataset to detect anomalous phenomena. Although Sentinel data hasa great potential due to its fine spatial resolution, harmonization with MODIS isneeded. Keywords: oak lace bug, Corythucha arcuata; forest, NDVI; MODIS; phenology;disturbances [ABSTRACT FROM AUTHOR]

Trees growing on sites with poorer nutrient availability allocate greater share of carboninto roots, at the expense of aboveground biomass growth. Consequently, a linkbetween the ratio of aboveground net primary productivity (ANPP) and fine rootbiomass (FR) and soil organic carbon (SOC) and total soil nitrogen (TSN) shouldexist. We set a chronosequence experiment was set up in April 2010, consisting of eight standsaged from 5 to 168 years with pedunculate oak (Quercus robur L.) as a dominant tree species.In 32 plots (four per stand), on approximately 640 trees in total, dendrometer bands wereinstalled and measured for assessing NPPwood while NPPleaves&seeds was determined fromlitterfall traps. At the beginning of 2012 we took 128 soil cores (16 per stand) down to 40 cm depth inthe mineral layer with a split-tube sampler. The soil sampling was repeated in May 2017.Each soil core was divided into four subsamples according to predetermined depths (5, 10, 20and 40 cm) Roots were extracted from soil samples and washed. Fine roots (0.25 mm < d <2mm) were separated, dried, weighed and analysed for C and N in elemental analyser. SOCand TSN stocks were calculated for each soil core, while ANPP was calculated at eachsubplot. Additional experiment of fine root production was set in March 2016 in one stand(45 y. old) yielding the estimate for the average annual production of fine roots of 0.57 tCha1y−1. ANPP ranged from 3.4 to 8.8 t C ha−1 yr−1 (excluding 5 yrs. old stand), while FRstocks ranged from 1.1 to 5.7 t C ha−1, with highest values observed in two youngest stands.SOC and TSN stocks ranged from 55.9 to 122.4 t C ha−1 and 3.9 to 13.7 t N ha−1,respectively, with C/N ratio ranging from 8.8 to 16.4. Results confirmed our hypothesis,namely the ratio ANPP : FR significantly positively correlates with SOC and TSN inpedunculate oak forest. [ABSTRACT FROM AUTHOR]

We analysed 10 years (2008–2017) of continuous eddy covariance (EC) CO2 fluxmeasurements of net ecosystem exchange (NEE) in a young pedunculate oak forest inCroatia. Measured NEE was gap-filled and partitioned into gross primary productivity (GPP)and ecosystem reparation (RECO) using the online tool by Max Planck Institute forBiogeochemistry in Jena, Germany. Annual NEE, GPP, and RECO were correlated with mainenvironmental drivers. Net primary productivity was estimated from EC (NPPEC), as a sumof -NEE and Rh obtained using a constant Rh : RECOratio, and from independent periodicbiometric measurements (NPPBM). For comparing the NPP at the seasonal level, we proposea simple model that aimed at accounting for late-summer and autumn carbon storage in thenon-structural carbohydrate pool. Over the study period, Jastrebarsko forest acted asa carbon sink, with an average (±std. dev.) annual NEE of -319 (±94) gC m−2y−1, GPP of 1594 (±109) gC m−2 y−1, and RECO of 1275 (±94) gC m−2 y−1.Annual NEE showed high inter-annual variability and poor correlation with annualaverage global radiation, air temperature, and total precipitation, but significant (R2 =0.501, p = 0.02) correlation with the change in soil water content between May andSeptember. Comparison of annual NPPEC and NPPBM showed a good overallagreement (R2 = 0.463, p = 0.03), although in all years NPPBMwas lower thanNPPEC, with averages of 680 (±88) gC m−2 y−1 and 819 (±89) gC m−2 y−1,respectively. Lower values of NPPBM indicate that fine roots and grasses contributionsto NPP, which were not measured in the study period, could have an importantcontribution to the overall ecosystem NPP. At a seasonal level, two NPP estimates showeddifferences in their dynamic, but the application of the proposed model greatlyimproved the agreement in the second part of the growing season. Further researchis needed on the respiration partitioning and mechanisms of carbon allocation. [ABSTRACT FROM AUTHOR]