Leaf area index of Norway spruce stands in relation to age and defoliation

Pokorný, Radek; Stojnić, Srđan

doi:10.11118/beskyd201205020173

Cited by 26 publications

(18 citation statements)

References 26 publications

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“…Values of LAI (as measured by LAI-2200) varied between 5.3 and 9.3, which is in agreement with measurements done by Pokorný and Stojnič (2012), who measured LAI of 17 Norway spruce stands between 15 and 102 years located in the Těšínské Beskydy Mts. (NE of the Czech Republic).…”

Section: Leaf Area Indexsupporting

confidence: 75%

In situ data supporting remote sensing estimation of spruce forest parameters at the ecosystem station Bílý Kříž

Homolová

Janoutová

Lukeš

et al. 2017

Beskydy

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Homolová L., Janoutová R., Lukeš P., Hanuš J., Novotný J., Brovkina O., Loayza Fernandez R. R. 2017: In situ data collection supporting remote sensing estimation of spruce forest parameters at the ecosystem station Bílý Kříž -Beskydy, 10 (1, 2): 75-86Remote sensing offers an effective way of mapping vegetation parameters in a spatially continuous manner, at larger spatial scales and repeatedly in time compared to traditional in situ mapping approaches that are typically accurate, but limited to a few distributed location and few repetitions. In case of forest ecosystems, remote sensing allow to assess quantitative parameters or indicators related to forest health status such as leaf area index, leaf pigment content, chlorophyll fluorescence, etc. Development, calibration and validation of remote sensing-based methods, however, still rely on supportive in situ data. The aim of this contribution is to introduce the individual in situ components in the framework for the retrieval of forest quantitative parameters from airborne imaging spectroscopy data. All measurements were acquired during an extensive in situ/flight campaign that took place at the Norway spruce dominated study site Bílý Kříž (MoravianSilesian Beskydy Mts., Czech Republic) during August 2016. In addition to airborne remote sensing data acquisition, the in situ activities included terrestrial laser scanning for tree 3D modelling, measurements of needle biochemical and optical properties, leaf area index measurements and spectral measurements of various natural and artificial surfaces. Leaf pigments varied between 25.2 and 49.1 µg cm -2 for chlorophyll a+b content, 4.9 -10.6 µg cm -2 for carotenoid content depending on needle age and its adaptation to sun illumination, whereas ratio between the two pigments was stable around 4.6 -5. 3. Specific leaf area of spruce needles varied between 49.3 and 105.8 cm 2 g -1 , being the highest for the shade adapted needles of the current year. Leaf area index of spruce stands of various age and densities varied between 5.3 and 9. 3.

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Section: Leaf Area Indexsupporting

confidence: 75%

In situ data supporting remote sensing estimation of spruce forest parameters at the ecosystem station Bílý Kříž

Homolová

Janoutová

Lukeš

et al. 2017

Beskydy

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“…Scots pine is a rather drought tolerant species while Norway spruce requires moist sites (Schmidt-Vogt, 1991;Modrzynski, 2007). Scots pine is a light demanding, early-successional species with low LAI (Bequet et al, 2012), while Norway spruce is more shade tolerant, late successional-species (Brzeziecki & Kienast, 1994) with twice the LAI (Pokorny and Stojnic, 2012). Due to the double LAI, deposition is higher for Norway spruce than for Scots pine.…”

Section: Discussion Species Traits Niches and Hypothesized Causes Fmentioning

confidence: 99%

Mixed stands of Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst] can be more productive than monocultures. Evidence from over 100 years of observation of long-term experiments

2014

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Many studies underline the importance of species diversity for most forest functions and services (Zhang et al., 2012;Gamfeldt et al., 2013). Close-to-nature mixed species stands are widely held to supply many ecological, economical and social forest goods and services in a similar or even better way than far-from-nature monocultures (Hector & Bagchi, 2007;Piotto, 2008;Forrester, 2014 AbstractAim of study: The objective of this study was to analyse the effect of species mixing of Scots pine and Norway spruce on the productivity at the stand and species level. We also analysed to what extent the mixing effects is modified by drought stress.Area of study: The study was conducted in N-E Poland and based on three experiments located in Maskulinskie, Strzal / owo and Kwidzyn Forest Districts.Material and methods: We evaluated long-term mixed-species experiments in Scots pine and Norway spruce which are under continuous survey since more than 100 years. Stand productivity was analysed based on the periodic annual increment and total yield of stem volume. Growth and yield were compared between mixed and neighbouring pure stands. As a substitute for the missing Norway spruce monocultures, we used appropriate yield table data. In order to characterize the effect of water supply on the mixing effects, we correlated the Martonne index of aridity with the ratio of Scots pine growth in mixed versus pure stands.Main results: We found that the mixed stands exceed the weighted mean of the pure stands' volume productivity on average by 41%. At the species level Scots pine benefits from the mixture by 34% and Norway spruce by 83%. Growth periods with harsh climate conditions reinforce overyielding, while periods with mild conditions reduce the benefit of mixing. The overyielding of mixed stands, especially when growing under unfavourable conditions, is explained by niche complementarity of both species and discussed in view of the stress-gradient-hypothesis.Research highlights: The revealed overyielding of mixed compared with neighbouring pure stands, particularly under harsh weather conditions, substantiates the preferences of Scots pine-Norway spruce mixtures regarding climate change.Key words: drought resilience; mixed stand; pure stand; facilitation; competition; overyielding; underyielding. This work has two Supplementary Figures that do not appear in the printed article but that accompany the paper online Abbreviations: PAIV (periodic annual increment of stem volume, in m 3 ha -1 yr -1 ); RPAIV (relationship between PAIV of a species in pure versus mixed stands); TY (total yield of merchantable stem volume ≥ 7 cm over bark, in m 3 ha -1 ); RTY (ratio between TY of a species in pure versus mixed stands); Ma (Martonne index of aridity).

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“…We compared simulated with observed actual evapotranspiration rates from eddy covariance measurements within the Wüstebach catchment (data not shown) and achieved best correspondence using a k value of 0.75 and a LAI value of 4, which is within the range of typical LAI values for Norway spruce forests [ Pokorný and Stojnic , ]. The root water uptake was computed by the Feddes approach [ Feddes et al ., ] implemented in HYDRUS‐1D.…”

Section: Methodsmentioning

confidence: 99%

Accuracy of the cosmic-ray soil water content probe in humid forest ecosystems: The worst case scenario

et al. 2013

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[1] Soil water content is one of the key state variables in the soil-vegetation-atmosphere continuum due to its important role in the exchange of water and energy at the soil surface. A new promising method to measure integral soil water content at the field or small catchment scale is the cosmic-ray probe (CRP). Recent studies of CRP measurements have mainly presented results from test sites located in very dry areas and from agricultural fields with sandy soils. In this study, distributed continuous soil water content measurements from a wireless sensor network (SoilNet) were used to investigate the accuracy of CRP measurements for soil water content determination in a humid forest ecosystem. Such ecosystems are less favorable for CRP applications due to the presence of a litter layer. In addition, lattice water and carbohydrates of soil organic matter and belowground biomass reduce the effective sensor depth and thus were accounted for in the calibration of the CRP. The hydrogen located in the biomass decreased the level of neutron count rates and thus also decreased the sensitivity of the cosmic-ray probe, which in turn resulted in an increase of the measurement uncertainty. This uncertainty was compensated by using longer integration times (e.g., 24 h). For the W€ ustebach forest site, the cosmic-ray probe enabled the assessment of integral daily soil water content dynamics with a RMSE of about 0.03 cm 3 /cm 3 without explicitly considering the litter layer. By including simulated water contents of the litter layer in the calibration, a better accuracy could be achieved.

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Leaf area index of Norway spruce stands in relation to age and defoliation

Cited by 26 publications

References 26 publications

In situ data supporting remote sensing estimation of spruce forest parameters at the ecosystem station Bílý Kříž

In situ data supporting remote sensing estimation of spruce forest parameters at the ecosystem station Bílý Kříž

Mixed stands of Scots pine (Pinus sylvestris L.) and Norway spruce [Picea abies (L.) Karst] can be more productive than monocultures. Evidence from over 100 years of observation of long-term experiments

Accuracy of the cosmic-ray soil water content probe in humid forest ecosystems: The worst case scenario

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