1,721,266 research outputs found
Effects of tree species biodiversity on soil C and N pools: a regional case study in northern Italy
Full text linkSite conditions are known to affect local resource availability, therefore being an
important driver of plant species diversity. In this context, soil fertility is thought to
influence the relationship between plant species diversity and climate in forests
ecosystems. The data collected with the Regional Forest Carbon Inventory of the
Trento Province (InFoCarb), on 150 plots of 600 m2
size, were used to investigate
possible impacts of tree biodiversity on local soil conditions. Biodiversity was
quantified both as Species Richness and with Biodiversity Indexes (Simpson's Index
and Shannon-Wiener index) moreover, canopy species evenness was expressed by
the Simpson's dominance index by using the proportions of basal area for each
constituent species. Forest floor and mineral soil were collected on three mini-pits
inside each sampling plot. Relationships between the soil C and N pools and tree
biodiversity were investigated with linear regressions whereas Boosted Regression
Trees models were used to highlight the main determinants of canopy species
diversit
Analysis of dense optical time series for the spectral and temporal characterization of bark beetle attacks
Full text linkEstimation of forest stem volume using ALS data and field data collected with relascopic technique
Full text linkNew technologies for forest monitoring in Alpine Region
No full textUsing IoT technologies represents a novel combination of disciplines (plant ecophysiology and hydrology) to unravel the vulnerability of ecosystem to climatic stress. Taking advantage of IoT, a new device the Tree-Talker, is developed to measure simultaneously important individual tree scale ecophysiological parameters as well as some additional ecosystem-related variables. Key parameters are: (1) tree radial growth, as an indicator of photosynthetic carbon allocation in biomass; (2) sap flow, as an indicator of tree transpiration and functionality of xylem transport; (3) xylem moisture content as indicator of hydraulic functionality 4) light penetration in the canopy in terms of fractional absorbed radiation and 5) light spectral components related to foliage dieback and physiology, 6) tree stability parameters to allow real time forecast of potential tree fallings. Additional parameters such as soil temperatures and moisture and meteorological variables will be also monitored at high frequency to have comparable time scale between abiotic parameters and short term plant responses. In this research, by using of 100 Tree-Talkers, the changes in forest have been monitored in northern Italy. In every tree, particular emphasis is placed on the hourly, daily, monthly and seasonal sap flow, xylem moisture content and plant movement fluctuations under different meteorological and soil moisture conditions. Granier-type thermal dissipation probe and heat pulse velocity (Vh) family of methods (Heat Ratio Mehtod and Tmax) were considered to measure and compare sap flow on the main stem of trees. In addition, Relation between diurnal-nocturnal xylem moisture content and sap flow have been defined in different species in Alpine area. Moreover, the risk of windthrow and uprooting have been studied by recording trees oscillations data in xyz axis due to the gravity. A direct relationship between the sap flow and air temperature has been demonstrated for a number of species with different conditions in hourly scale. While, xylem moisture content and air relative humidity have an inverse relation to sap flow. Our results revealed that sap flow has a different correlation with vapour pressure deficit (VPD) base on natural logarithm function in different species which shows stomata behaviour in wet or dry conditions. In addition, although sap flow significantly correlated with air temperature, the highest sap flow occurs a few times before the maximum daily temperature. Since by closing the stomata, plant responses to high midday temperature stress to reduce water loss
Effects of vegetation structure on the soil and canopy temperature of mountain meadows treated with different intensities
No full textCharacterizing forest carbon dynamics using multi-temporal lidar data
No full textRecent years have seen a rapid surge in the use of remote sensing technologies for characterizing the structure,
composition and function of forested landscapes. Yet with few exceptions these studies have only provided
snapshots of the ecosystem at one point in time, thereby limiting our ability to understand how forests are
responding to global change. New approaches for characterizing forest dynamics using multi-temporal remotely
sensed data are therefore urgently needed if we are to integrate these new technologies into conservation and
management decision making processes. By combining data from a network of forest plots with repeat airborne
lidar, here we develop an approach to (i) map fine-scale variation in aboveground carbon density (ACD) and its
change over time across the landscape, and (ii) link these changes in ACD to forest structural attributes, species
composition, disturbance regimes and local topography. We tested this framework on a temperate forest in the
Alps characterized by the presence of three dominant species: spruce (Picea abies), silver fir (Abies alba) and
beech (Fagus sylvatica). We found that between 2007 and 2011 the majority of the landscape (61.0%) increased
in ACD, with a much smaller fraction of the study area exhibiting evidence of small-scale natural disturbances
(3.7%) or ACD loss as a result of logging activities (13.7%). On average, areas of the landscape that actively
sequestered carbon did so at a rate of 3.6% per year. However, rates of ACD accumulation varied considerably
across the landscape, being greatest in forest stands characterized by multi-layered heterogeneous canopies, in
ones dominated by spruce and at lower elevations. We demonstrated the potential of repeat lidar for characterizing not only the structure, but also the composition and aboveground carbon dynamics of forests. In doing so we open the door to monitor forests across large and inaccessible landscapes in order to better understand
how they are responding to rapid global change and refine how we manage and conserve these critical ecosystem
A hierarchical dataset of vegetative and reproductive growth in apple tree organs under conventional and non-limited carbon resources
Full text linkA monitoring of apple fruit, shoot and trunk growth was performed on 15 trees, equally split according to three treatments, which determined heavily contrasting carbon assimilate availability: unmanipulated trees (FRU), thinned trees (THI) and defruited trees (DEF). Several variables describe the vegetative growth on FRU and DEF trees (shoot length, base diameter, number of fruits on shoot, and height, diameter, pruning intensity and number of fruits of the branch carrying the shoot; trunk circumference), as well as the fruit growth on FRU and THI trees (3 fruit diameters). Additional measurements from ancillary shoots (apical diameter, number of leaves, leaf dry weight, stem dry weight, fresh mass, volume) and fruits (3 diameters, dry weight) from trees undergoing the same treatments, provide a more complete (destructive) characterization of organs growth, thanks to several measurements performed across the growing season. Organs are provided with categorical variables indicating the treatment, tree, canopy height, orientation (for both shoots and fruit), as well as branch and shoot identifiers, so that hierarchical modeling of the dataset can be performed. The dataset is completed with dates and day of the year of the measurements and the accumulated growing degree days from full bloom. Data can be used to calculate apple tree absolute and relative growth rates, maximum potential growth rates, as well as shoot growth responses to thinning and pruning. The dataset can also be used to calibrate allometric relationships, estimate structural apple tree growth parameters and their variabilit
Delineation of individual tree crowns from ALS and hyperspectral data: A comparison among four methods
Full text linkIn this paper four different delineation methods based on airborne laser scanning (ALS) and hyperspectral data are compared over a forest area in the Italian Alps. The comparison was carried out in terms of detected trees, while the ALS based methods are compared also in terms of attributes estimated (e.g. height). From the experimental results emerged that ALS methods outperformed hyperspectral one in terms of tree detection rate in two of three cases. The best results were achieved with a method based on region growing on an ALS image, and by one based on clustering of raw ALS point cloud. Regarding the estimates of the tree attributes all the ALS methods provided good results with very high accuracies when considering only big trees
Monitoring of GHGs flux dynamics at the "Viote" mountain peatland (Eastern Alps, Italy) under climate change pressure
Full text linkThis presentation focuses on the alpine peatland "le Viote" (46.01 N, 11.04 E, 1560 m asl), located at the centre of a plateau in the Mt. Bondone area, in the eastern Italian Alps (Figure), where the fluxes of methane (CH4) and carbon dioxide (CO2) between the peatland ecosystem and the atmosphere have been measured by chamber technique since summer 2024. The objectives of the current research activities are to analyse the spatial and temporal variability of both GHGs with special attention to CH4 fluxes, considering the response to climatic drivers, the influence of peatland vegetation community types, hydrology and natural and anthropogenic disturbances history. These activities build on 10+ years of CO2 fluxes monitoring by eddy covariance and a more limited dataset of CH4 fluxes, providing a temporal background for detecting flux magnitude changes
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