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1.
Ten years of fluxes and stand growth in a young beech forest at Hesse, North-eastern France 总被引:1,自引:0,他引:1
André Granier Nathalie Bréda Bernard Longdoz Patrick Gross Jérôme Ngao 《Annals of Forest Science》2008,65(7):704-704
2.
Florence Maunoury-Danger Nicolas Chemidlin Prevost Boure Jérôme Ngao Daniel Berveiller Claude Brechet Eric Dufrene Daniel Epron Jean-Christophe Lata Bernard Longdoz Caroline Lelarge-Trouverie Jean-Yves Pontailler Kamel Soudani Claire Damesin 《Annals of Forest Science》2013,70(2):173-183
? Context
The carbon isotope composition of the CO2 efflux (δ13CE) from ecosystem components is widely used to investigate carbon cycles and budgets at different ecosystem scales. δ13CE, was considered constant but is now known to vary along seasons. The seasonal variations have rarely been compared among different ecosystem components.? Aims
We aimed to characterise simultaneously the seasonal dynamics of δ13CE in different compartments of two temperate broadleaved forest ecosystems.? Methods
Using manual chambers and isotope ratio mass spectrometry, we recorded simultaneously δ13CE and δ13C of organic matter in sun leaves, current-year twigs, trunk bases and soil in an oak and a beech forest during 1 year.? Results
In the two forests, δ13CE displayed a larger variability in the tree components than in the soil. During the leafy period, a pronounced vertical zonation of δ13CE was observed between the top (sun leaves and twigs with higher values) and bottom (trunk and soil with lower values) of the ecosystem. No correlation was found between δ13CE and δ13C of organic matter. Causes for these seasonal variations and the vertical zonation in isotope signature are discussed.? Conclusion
Our study shows clear differences in values as well as seasonal dynamics of δ13CE among different components in the two ecosystems. The temporal and local variation of δ13CE cannot be inferred from organic matter signature or CO2 emission rates. 相似文献3.
Context
Interactions of N and P cycles and those of other macro-elements in forests are scarcely known.Aim
This study compares the P cycle in two very different forest ecosystems where soil P availability is low (tropical dry forest in Mexico and Mediterranean forest in Spain) in relation to Ca, K, and Mg cycles.Methods
Compiled data belonging to these two forest sites are discussed, comparing the P and base cation budgets and exploring relationships among P and base cation cycles.Results
Broad differences between input and output of base cations were observed. Analysis of the P budget indicates P retention inside both forest ecosystems. The tropical dry forest has higher nutrient contents than those found in the Mediterranean temperate forest. Chemical composition of forest leaves and litters, and base cation?CP ratios varied according to soil P availability and cation concentrations. However, P resorption is higher in the tropical dry forest than in the temperate one.Conclusion
This study reveals the existence of P retention at the ecosystem level in both forests, but suggested P limitation at the Mediterranean forest seems to be stronger than that occurring at the tropical forest. 相似文献4.
Responses of labile soil organic carbon and enzyme activity in mineral soils to forest conversion in the subtropics 总被引:1,自引:0,他引:1
Aims
Globally, extensive areas of native forest have been almost replaced by plantations to meet the demands for timber, fuel material and other forest products. This study aimed to evaluate the effects of forest conversion on labile soil organic C (SOC), soil respiration, and enzyme activity, and to quantify their relationship in subtropical forest ecosystems.Methods
Surface mineral soil (0–20 cm) was collected from a Cunninghamia lanceolata Hook. plantation, Pinus massoniana Lamb. plantation, Michelia macclurei Dandy plantation, and an undisturbed native broadleaf forest. Soil microbial biomass C, dissolved organic C, permanganate-oxidizable C, basal respiration, and six enzyme activities were investigated.Results
Soil microbial biomass C was higher by 45.9 % in native broadleaf forest than that in M. macclurei Dandy plantation. The ratio of soil microbial biomass C to total SOC was 27.6 % higher in the M. macclurei Dandy plantation than in the native broadleaf forest. The soil respiration increased by 25.2 % and 21.7 % after conversion from native broadleaf forest to P. massoniana Lamb. and M. macclurei Dandy plantations respectively. The effects of forest conversion on the soil enzyme activities differed among the tree species. Soil microbial biomass C had higher correlation with soil respiration than with the other SOC fractions. Moreover, soil microbial biomass C was positively correlated with urease and negatively correlated with cellulase activity. Soil respiration had higher correlation with soil microbial biomass C, dissolved organic C and permanganate-oxidizable C.Conclusion
Forest conversion affected the soil microbial biomass C, soil respiration, invertase, cellulase, urease, catalase, acid phosphatase, and polyphenol oxidase activities, but their response depended on tree species. Soil respiration was mainly controlled by labile SOC, not by total SOC. 相似文献5.
Laura Heid Christophe Calvaruso Anjy Andrianantenaina André Granier Sébastien Conil Cyrille B. K. Rathgeber Marie-Pierre Turpault Bernard Longdoz 《Annals of Forest Science》2018,75(1):31
Key message
In order to record the seasonal changes in aboveground biomass production (trunk and branches) in a forest, changes in wood density must be taken into account. A 60-year-old beech forest displayed a large intra-annual variability in its aboveground woody biomass production efficiency. This variation followed a seasonal trend with a maximum during the summer while gross primary production was rather low.Context
In the current context of land use and climate change, there is a need to precisely quantify the carbon (C) balance of forest ecosystems, and more specifically, of C allocation to tree compartments.Aims
We quantified the seasonal changes in the aboveground biomass production (aBP) of a beech forest growing on two different soils: an alocrisol and a calci-brunisol. In addition, for the alocrisol ecosystem, we assessed the existence and degree of intra-annual variability in the ratio of wood aBP to gross primary production (GPP), i.e., the wood aBP efficiency.Methods
The study site is a 60-year-old beech forest in northeastern France. An eddy covariance tower records continuously net ecosystem exchange. To investigate the temporal changes in aBP, mini-cores were drilled and diameter at breast height measurements were taken on a monthly basis from 45 trees for both stands studied over 2014.Results
A clear difference in aBP was observed between the two soils with the alocrisol being more productive than the calci-brunisol. For the alocrisol, both woody aBP and GPP changed over the course of the year, reaching peak values during June (6 and 12.5 gC m?2 day?1, respectively). Wood applied bias photon-to-current efficiency aboveground Biomass Production Efficiency (aBPE) also showed important intra-annual variations, ranging from 0.09 in September to 0.58 in July. Wood density varied throughout the year, and not taking it into account would have led to an overestimation of aBP by as much as 20% in April and May.Conclusion
Our study highlights the importance of taking wood density into account for intra-annual studies of aBP. Wood aBPE cannot be considered as constant as it fluctuated from 0.09 to 0.58 throughout the year for an annual value of 0.34. The potential error in wood aBPE stemming from not taking these changes into account amounts to 15%.6.
F. Lombardi P. Cherubini R. Tognetti C. Cocozza B. Lasserre M. Marchetti 《Annals of Forest Science》2013,70(1):101-111
Context
We investigated the relationships between decay classes, morphological characteristics and chemical compounds in Abies alba Mill. and Fagus sylvatica L. stumps in two forest stands in the central Apennines (Italy). The analysis of deadwood decomposition is important in estimating carbon sequestration potential and carbon residence time in forest ecosystems. In addition, deadwood decomposition affects nutrient cycling and microhabitat distribution.Aims
The overall aim of this study was to investigate the decomposition processes in a mountainous Mediterranean ecosystem, and specifically to assess changes in chemical variables (lignin, cellulose, carbon and nitrogen content) in deadwood during the decomposition process, in relation to decay classes and to the species.Methods
Cross-sections were collected from stumps. Samples were assigned to visually discernible decay classes, and cellulose, lignin and carbon (C) and nitrogen (N) content in relation to total dry mass were analysed during the decay process.Results
Results showed how C/N ratio decreased over decades due to an increase in nitrogen content. On the contrary, carbon concentration in stumps remained substantially stable. Lignin degraded slowly in comparison with cellulose and differences between species were observed.Conclusion
The hypothesis that the conifer species would decompose faster than deciduous species did not prove correct. The slower decay of lignin compared to cellulose suggested that lignin could be an important long-term source of soil organic carbon, and that this process could be greatly affected by forest species mixtures. Finally, decomposition processes in the investigated montane?CMediterranean forests were definitely faster than in the colder climates of northern Europe. 相似文献7.
Yasuko Mizoguchi Yoshikazu Ohtani Satoru Takanashi Hiroki Iwata Yukio Yasuda Yuichiro Nakai 《Journal of Forest Research》2012,17(3):283-295
Carbon dioxide (CO2) flux was measured above the forest at the Fujiyoshida site on the northern slope of Mount Fuji in Japan in 2000?C2008 using an eddy covariance technique. The forest mainly consists of Japanese red pine (Pinus densiflora) and Japanese holly (Ilex pedunculosa). The 9-year average of monthly mean net ecosystem production (NEP) ranged from ?0.1?g?C?m?2?day?1 in January to 2.5?g?C?m?2?day?1 in May. The maximum net uptake was observed in May, although gross primary production (GPP) was highest in July. Variation in the leaf amount did not notably affect seasonal variation in GPP. This site was characterized by carbon uptake even in winter, if the meteorological conditions were conducive for photosynthesis and a resulting long period of carbon uptake. The 9-year averages of annual NEP, GPP, and ecosystem respiration (RE) were 388, 1,802, and 1,413?g?C?m?2?year?1, respectively. The annual NEP was lowest in 2003 and highest in 2004 over the 9?years. Year-to-year variability of NEP mainly depended on air temperature and photosynthetically active radiation in summer, and the dependence of the deviation of annual NEP on that of GPP was greater than that of RE. Long-term observational data indicated that the carbon uptake ability at the study site was at a moderate level in comparison with other temperate humid evergreen forests around the world. These data also indicated that the site had a high carbon uptake ability compared with other deciduous forests in Japan because of the duration of carbon uptake. 相似文献
8.
Giovanni Di Matteo Irene Tunno Pierfrancesco Nardi Paolo De Angelis Giada Bertini Gianfranco Fabbio 《Annals of Forest Science》2014,71(8):885-895
Context
Harvesting of Mediterranean oak coppice forests has been progressively suspended on a share of cover over the last decades. Positive growth trend in outgrown coppices no longer harvested on short rotations now drives natural forest restoration on wide areas, and it represents a potential carbon sink in view of global warming.Aims
Our goals were to estimate carbon (C) and nitrogen (N) content per compartment in two deciduous oak outgrown coppice forests, aged differently and growing under unequal site quality, to verify whether C concentration across compartments is in agreement with the conventional conversion rate of 0.5.Methods
Ecosystem C and N pools were assessed by multiplying the whole coppice mass (combining specific allometric functions, root-to-shoot ratio, and soil sampling) by respective C and N concentrations.Results
The results point out that the largest percentage of N was stored in 15-cm topsoil (84.06 and 73.34 % at the younger and older site, respectively), whereas the proportion of organic ecosystem C pool was more variable, as a consequence of the amount and allocation of phytomass. We found that, in most cases, C concentration was less than the conventional conversion rate of 0.5, especially in deadwood, O layer, and root compartments.Conclusion
The findings provide further knowledge of C and N storage into these new built-up forest types and the evidence that a detailed analysis may get higher accuracy in the pools estimate, producing a more reliable outlook on dynamics and climate change mitigation ability of these systems. 相似文献9.
Efrat Sheffer 《Annals of Forest Science》2012,69(4):429-443
Context
Mediterranean landscapes are composed of different interacting vegetation patches. Pine and oak ecosystems form contiguous patches within these landscapes, in pure stands, or as mixed pine?Coak ecosystems. During the nineteenth century, pine forest distribution in the Mediterranean Basin increased dramatically as a result of large-scale re-forestation and spontaneous forest regeneration. At the same time, secondary succession of abandoned agricultural land allowed development of pine and oak ecosystems. Consequently, a pine?Coak mosaic has developed, which created opportunities for cross-colonization, i.e. species colonization from one ecosystem in the reciprocal system. Pines shed their wind-dispersed seeds and colonize Mediterranean oak vegetation. Oaks regenerate in different ecosystems, including pine forest understories.Research question
This paper reviews fire-free landscape-scale dynamics of pine?Coak Mediterranean mosaics and analyze how landscape-scale interactions are leading to pine?Coak ecosystems by different processes.Results
Published information from the Mediterranean Basin illustrates pathways of pine?Coak ecosystems formation. Using Mediterranean literature, I try to elucidate the factors that (1) control colonization potential and (2) modulate the resistance to colonization, in different habitats, land uses, and landscape settings.Conclusion
Management implications for these mixed pine?Coak ecosystems are suggested. The question of whether they are novel ecosystems is discussed. 相似文献10.
Soil enzyme activities as potential indicators of soluble organic nitrogen pools in forest ecosystems of Northeast China 总被引:1,自引:0,他引:1
Context
Soluble organic nitrogen is considered to reflect the effect of forest types on soil nitrogen status. As a major process affecting the soil-soluble organic nitrogen pool, degradation of insoluble organic nitrogen in the production of soluble organic nitrogen is mediated by a suite of soil enzymes.Aims
This study aims to examine soil-soluble organic nitrogen pools and their relationships with the activities of soil enzymes in natural secondary forest stands and adjacent larch plantation stands.Methods
Four pairs of larch plantation stands and secondary forest stands were randomly selected from a mountainous area, and the top 15?cm of the mineral soils were sampled from each field.Results
The soil-soluble organic nitrogen concentrations were up to 2-fold greater in the secondary forest stands than in the larch plantation stands, whereas the ratio of soluble organic nitrogen/total nitrogen was comparable between the two forest types. The concentrations of soluble organic nitrogen were positively correlated with approximately 2-fold differences in urease and protease activities, a 1.2-fold difference in N-acetyl-??-glucosaminidase and a 1.7-fold difference in l-asparaginase between the two forest types.Conclusions
Our results suggest that relationships between soil-soluble organic nitrogen and enzyme activities are independent on sampling time, and that the soil enzyme activities can be used as potential indicators of soil soluble organic nitrogen pools in the temperate forest ecosystem. 相似文献11.
? Context
Models for predictions of soil compaction following forest traffic represent important decision tools for forest managers in order to choose the best management practices for preserving soil physical quality. In agricultural soil compaction research, analytical models are widely used for this purpose.? Aims
Our objective was to assess the ability of an analytical model to predict forest soil compaction under forwarder traffic.? Methods
We used the results from two experimental sites set up in north-eastern France in 2007 and 2008 to compare simulations using the SoilFlex model with observed bulk density following forwarder traffic.? Results
The best model-based predictions were found when considering the mean initial soil conditions and an increased rebound parameter in the upper soil layers (0–10 cm) in comparison to the deeper layers (10–50 cm). The need to increase the rebound parameter in the soil surface layer to improve model accuracy was attributed to a large soil organic matter content in the uppermost layers of forest soils. For the site where initial soil mechanical parameters were measured as a function of soil bulk density and water content, the model performance was good, with a root mean square error (RMSE) of 0.06. The model performed poorer (RMSE of 0.11), especially for the surface soil layer, for the second site that was wetter at the time of traffic and where soil mechanical properties were not measured but estimated by means of pedo-transfer functions.? Conclusions
SoilFlex was found to yield satisfactory predictions and could help forest managers estimate the risk of compaction and to select the most appropriate machinery for given soil conditions in order to preserve the soil from physical degradation during traffic in forest ecosystems. However, our results emphasise the need for research on soil mechanical properties of forest soils, in particular on the role of soil organic matter and roots on soil compressive properties. 相似文献12.
? Context
The Kyoto Protocol allows the use of domestic forest carbon sequestration to offset emissions to a limited degree, while bioenergy as an unlimited emission reduction option receives substantial financial support in many countries.? Aim
The primary objective of this study was to analyze (1) whether these limits on forest carbon sequestration would be binding, thereby leading to inefficient mitigation, and (2) the total potential effect of the protocol on the greenhouse gas (GHG) fluxes in the forest sector.? Methods
A partial equilibrium model of the Norwegian forest sector was used to quantify the GHG fluxes in a base scenario with no climate policy, a Kyoto Protocol policy (KP policy), and a policy with no cap on forest carbon sequestration (FC policy), assuming that the policies apply the rest of the century.? Results
Carbon offsets are higher under the KP policy than in the base scenario and likewise higher than under the FC policy in the short run, but the KP policy fails to utilize the forest carbon sequestration potential in the long run as it provides considerably less incentives to invest in forestry than the FC policy.? Conclusion
The KP increases the Norwegian forest sector’s climate change mitigation compared to no climate policy but less in the long run than a carbon policy with no cap on forest carbon credits. 相似文献13.
Carbon stock changes of forest land in Finland under different levels of wood use and climate change
Risto Sievänen Olli Salminen Aleksi Lehtonen Paavo Ojanen Jari Liski Kimmo Ruosteenoja Mikko Tuomi 《Annals of Forest Science》2014,71(2):255-265
Context
Prediction of the effect of harvests and climate change (CC) on the changes in carbon stock of forests is necessary both for CC mitigation and adaptation purposes.Aims
We assessed the impact of roundwood and fuelwood removals and climate change (CC) on the changes in carbon stock of Finnish forests during 2007–2042. We considered three harvest scenarios: two based on the recent projections of roundwood and fuelwood demand, and the third reflecting the maximum sustainable cutting level. We applied two climate scenarios: the climate was in the state that prevailed around year 2006, or it changed according to the IPCC SRES A1B scenario.Methods
We combined the large-scale forestry model MELA with the soil carbon model Yasso07 for mineral soils. For soils of drained, forested peatlands, we used a method based on emission factors.Results
The stock change of trees accounted for approximately 80 % of the total stock change. Trees and mineral soils acted as carbon sinks and the drained peatland soils as a carbon source. The forest carbon sink increased clearly in both of the demand-based scenarios, reaching the level of 13–20 Tg C/year (without CC). The planned increase in the use of bioenergy reduced the forest sink by 2.6 Tg C/year. CC increased the forest carbon sink in 2042 by 38 %–58 % depending on the scenario. CC decreased the sink of mineral soils in the initial years of the simulations; after 2030, the effect was slightly positive. CC increased the emissions from the drained peatland soils.Conclusions
It is likely that forest land in Finland acts as a carbon sink in the future. The changes in carbon stocks of trees, mineral soils, and peatland soils respond differently to CC and fuelwood and roundwood harvests. 相似文献14.
Evy Ampoorter An de Schrijver Lotte van Nevel Martin Hermy Kris Verheyen 《Annals of Forest Science》2012,69(5):533-542
Context
Nowadays, harvest operations are predominantly performed fully mechanized using heavy tractors or forestry machines. The resulting soil compaction may negatively affect the soil ecosystem.Aims
We wanted to draw general conclusions concerning the impact of mechanized harvesting on forest soil bulk density and the influencing factors.Method
Therefore, we combined the data of several studies using a meta-analysis approach.Results
The impact decreased from the surface towards deeper soil layers. At 0?C10?cm depth, the impact on clayey soils was highest although not significantly different from the impact on sandy soils. Higher initial bulk densities, i.e., on already compacted forest soils, generally led to smaller extra increases of bulk density after machine traffic. For sandy soils, the impact was also significantly smaller when machines were lighter. No significant relationship was observed between the compaction degree and traffic intensity.Conclusions
We observed clear compaction on both clayey and sandy soils, especially in case of low initial soil compaction degrees and heavy machines. The compacted initial state of many forest soils, the long recovery period, and the generally high impact of the first passes that is frequently mentioned in literature all count in favour of designated skid trails and an adjustment of the machine type to the job. 相似文献15.
Context
Current decision analysis techniques are ineffective for planning thinning operation to improve the forest structure.Aims
The purpose of this study is to use multi-coefficient goal programming (GP) to plan a thinning schedule that allows more carbon sequestration and diverse forest structure.Methods
A multi-coefficient GP is applied to plan a thinning schedule for a 2,633-ha plantation forest.Results
This technique efficiently fine-tunes the thinning schedule to obtain 420,500 tons of carbon sequestration which was a little higher than the result by a multi-segment goal programming (MSGP). Moreover, a fixed-ratio multi-coefficient GP is applied to efficiently generate mosaic of thinned areas with various thinning intensities. Although the captured carbon by a fixed-ratio multi-coefficient GP is lower, the thinned areas can provide various habitats for forest life with multiform contrasting edges.Conclusion
The use of a multi-coefficient GP allows practicable planning of better thinning alternatives to increase carbon sequestration and forest structure. 相似文献16.
Christopher Reyer Petra Lasch-Born Felicitas Suckow Martin Gutsch Aline Murawski Tobias Pilz 《Annals of Forest Science》2014,71(2):211-225
? Context
Projecting changes in forest productivity in Europe is crucial for adapting forest management to changing environmental conditions.? Aims
The objective of this paper is to project forest productivity changes under different climate change scenarios at a large number of sites in Europe with a stand-scale process-based model.? Methods
We applied the process-based forest growth model 4C at 132 typical forest sites of important European tree species in ten environmental zones using climate change scenarios from three different climate models and two different assumptions about CO2 effects on productivity.? Results
This paper shows that future forest productivity will be affected by climate change and that these effects depend strongly on the climate scenario used and the persistence of CO2 effects. We find that productivity increases in Northern Europe, increases or decreases in Central Europe, and decreases in Southern Europe. This geographical pattern is mirrored by the responses of the individual tree species. The productivity of Scots pine and Norway spruce, mostly located in central and northern Europe, increases while the productivity of Common beech and oak in southern regions decreases. It is important to note that we consider the physiological response to climate change excluding disturbances or management.? Conclusions
Different climate change scenarios and assumptions about the persistence of CO2 effects lead to uncertain projections of future forest productivity. These uncertainties need to be integrated into forest management planning and adaptation of forest management to climate change using adaptive management frameworks. 相似文献17.
Megumi Kuroiwa Keisuke Koba Kazuo Isobe Ryunosuke Tateno Asami Nakanishi Yoshiyuki Inagaki Hiroto Toda Shigeto Otsuka Keishi Senoo Yuichi Suwa Muneoki Yoh Rieko Urakawa Hideaki Shibata 《Journal of Forest Research》2011,16(5):363-373
Measurements of gross NH 4 + and NO 3 ? production in forest soils were conducted using the 15N pool dilution method. Mineral topsoils (0?C10?cm depth) were collected from four forests from northern to southern Japan with a natural climate gradient to elucidate the mechanisms regulating gross nitrification rates in forest soils. Additionally, we attempted to evaluate the relative importance of heterotrophic nitrification in gross total nitrification using acetylene as a specific inhibitor of autotrophic nitrification. Distinct differences were found among sites in the gross rates of NH 4 + production (3.1?C11.4?mg?N?kg?1?day?1) and gross total nitrification (0.0?C6.1?mg?N?kg?1?day?1). The rates of gross heterotrophic nitrification were low in this study, indicating that heterotrophic nitrification is of minor importance in most forest mineral topsoils in Japan. Significant relations were found between gross autotrophic nitrification and gross NH 4 + production, soil N, and soil C concentrations, but none was found between gross autotrophic nitrification and soil pH. We determined the critical value of the gross NH 4 + production rates for gross autotrophic nitrification under which no gross autotrophic nitrification occurred, as well as the critical soil C/N ratio above which gross autotrophic nitrification ceased. Results show that tight coupling of production and consumption of NH 4 + prevents autotrophic nitrifiers from utilizing NH 4 + as long as NH 4 + availability is low. 相似文献
18.
Angelo Nolè Angelo Rita Agostino Maria Silvio Ferrara Marco Borghetti 《Annals of Forest Science》2018,75(3):83
Key message
A remote sensing-based approach was implemented to detect the effect of a late spring frost on beech forests in the Mediterranean mountain region. The analysis of spatio-temporal variability of frost effects on normalised difference vegetation index (NDVI) highlighted the distribution of the canopy damage across the forest according to geomorphic factors such as slope, aspect, and altitude.Context
Increased intensity and frequency of extreme temperatures such as late spring frosts and heat waves represent the main drivers affecting forest ecosystem structure and composition in the Mediterranean region.Aims
The main objective of this study was to evaluate the effects of a late spring frost disturbance, which occurred during spring 2016 in southern Italy, through the assessment of the spatial pattern of the damage to the beech forest canopy associated with the peak decrease in normalised difference vegetation index (NDVI), and the analysis of the NDVI temporal recovery after this frost disturbance.Methods
The forest areas affected by frost were detected through the NDVI differencing technique based on Landsat 8 (OLI/TIRS) imagery time series. The influence of local geomorphic factors (i.e., aspect, elevation, and slope) on forest NDVI patterns was assessed by means of a generalized additive model (GAM).Results
A rather counterintuitive NDVI patterns emerged according to the forest exposition, with NDVI significantly higher on the north facing areas than the southerly ones. The main canopy damage occurred at about 1250 m and reached up to 1500 m asl, representing the altitudinal range affected by the frost disturbance. Finally, the full canopy recovery occurred within 3 months of the frost event.Conclusion
The analysis of seasonal Landsat 8 image time series related to local geomorphic factors, such as aspect, slope, and altitude, and plant phenology on a frost event date, contributed to highlight the NDVI spatio-temporal variation and canopy recovery of a Mediterranean mountain beech forest.19.
Aims
This study aims to evaluate the effects of wood ash application on nutrient dynamics and soil properties of an acidic forest soil (Arenosol).Methods
Treatments were loose and pelleted ash application (11?Mg?ha?1), alone or together with N fertiliser, and control treatment in a lysimeter experiment. Nutrient leaching was followed during a 2-year period and soil chemical and biological properties were evaluated at the end of the experiment.Results
Wood ash increased leaching of total N, NH 4 + -N, base cations and P, mainly during the first months, the effect being more pronounced for the loose formulation. At the end of the study period, a positive effect on soil nutrient availability and soil acidity reduction was seen. The application of loose and pelleted ash alone decreased N leaching and increased N microbial biomass at the end of the experiment. The C dynamics was weakly affected.Conclusion
Wood ash can be used to improve nutrient availability and balance nutrient exported by tree harvesting in acid forest soils, the effects at short-term being stronger for loose than for pelleted ash. However, their application should be carried out when vegetation is established to minimise nutrient losses at short-term and reduce the potential risk for water bodies. In N-limited soils, wood ash should be applied with N fertilisers to counteract N immobilisation. 相似文献20.
Interannual variability of net ecosystem production for a broadleaf deciduous forest in Sapporo, northern Japan 总被引:1,自引:0,他引:1
Kenzo Kitamura Yuichiro Nakai Satoru Suzuki Yoshikazu Ohtani Katsumi Yamanoi Tomoki Sakamoto 《Journal of Forest Research》2012,17(3):323-332
To estimate net ecosystem production (NEP), ecosystem respiration (R E), and gross primary production (GPP), and to elucidate the interannual variability of NEP in a cool temperate broadleaf deciduous forest in Sapporo, northern Japan, we measured net ecosystem exchange (NEE) using an eddy covariance technique with a closed-path infrared gas analyzer from 2000 to 2003. NEP, R E, and GPP were derived from NEE, and data gaps were filled using empirical regression models with meteorological variables such as photosynthetic active radiation and soil temperature. In general, NEP was positive (CO2 uptake) from May to September, either positive or negative in October, and negative (CO2 release) from November to the following April. NEP rapidly increased during leaf expansion in May and reached its maximum in June or July. The four-year averages (±?standard deviation) of annual NEP, GPP, and R E were 443?±?45, 1,374?±?39, and 931?±?11?g?C?m?2?year?1, respectively. The lower annual NEP and GPP in 2000 may have been caused by lower solar radiation in the foliated season. During the foliated season, monthly GPP varied from year to year more than monthly R E. Variations in the amount of incoming solar radiation may have caused the interannual variations in the monthly GPP. Additionally, in May, the timing of leaf expansion had a large impact on GPP. Variations in GPP affected the interannual variation in NEP at our site. Thus, interannual variation in NEP was affected by the incoming solar radiation and the timing of leaf expansion. 相似文献