The purpose of this paper is to evaluate the forest health condition in the area of Hydropower plant Gabčikovo using the digital multispectral aerial images from 2011 in the section Dobrohošt - Sap. We proposed a new innovative procedure of creating the forest mask in the image processing. It concerns a process of defining tree crowns, where we combined subject and raster oriented approach of the image classification. We evaluated forest health condition on a selected forest mask using the method of twophased sampling with regression. The indicators of health condition were tree defoliation and presence of heavily damaged trees and snags in the stands. Defoliation was used to compare the current forest health condition in the concerned area with the data from 2008. Presence of the snags as the result of severe damage is interpreted in terms of stand types related to site conditions. Field survey proved presence of invasive and non-native tree species and plants. Based on the result, we have formulated recommendations for further forest monitoring in the Danube River inundation

peer reviewed | Large tropical trees and a few dominant species were recently identified as the main structuring elements of tropical forests. However, such result did not translate yet into quantitative approaches which are essential to understand, predict and monitor forest functions and composition over large, often poorly accessible territories. Here we show that the above-ground biomass (AGB) of the whole forest can be predicted from a few large trees and that the relationship is proved strikingly stable in 175 1-ha plots investigated across 8 sites spanning Central Africa. We designed a generic model predicting AGB with an error of 14% when based on only 5% of the stems, which points to universality in forest structural properties. For the first time in Africa, we identified some dominant species that disproportionally contribute to forest AGB with 1.5% of recorded species accounting for over 50% of the stock of AGB. Consequently, focusing on large trees and dominant species provides precise information on the whole forest stand. This offers new perspectives for understanding the functioning of tropical forests and opens new doors for the development of innovative monitoring strategies.

International audience | Large tropical trees and a few dominant species were recently identified as the main structuring elements of tropical forests. However, such result did not translate yet into quantitative approaches which are essential to understand, predict and monitor forest functions and composition over large, often poorly accessible territories. Here we show that the above-ground biomass (AGB) of the whole forest can be predicted from a few large trees and that the relationship is proved strikingly stable in 175 1-ha plots investigated across 8 sites spanning Central Africa. We designed a generic model predicting AGB with an error of 14% when based on only 5% of the stems, which points to universality in forest structural properties. For the first time in Africa, we identified some dominant species that disproportionally contribute to forest AGB with 1.5% of recorded species accounting for over 50% of the stock of AGB. Consequently, focusing on large trees and dominant species provides precise information on the whole forest stand. This offers new perspectives for understanding the functioning of tropical forests and opens new doors for the development of innovative monitoring strategies.

Large tropical trees and a few dominant species were recently identified as the main structuring elements of tropical forests. However, such result did not translate yet into quantitative approaches which are essential to understand, predict and monitor forest functions and composition over large, often poorly accessible territories. Here we show that the above-ground biomass (AGB) of the whole forest can be predicted from a few large trees and that the relationship is proved strikingly stable in 175 1-ha plots investigated across 8 sites spanning Central Africa. We designed a generic model predicting AGB with an error of 14% when based on only 5% of the stems, which points to universality in forest structural properties. For the first time in Africa, we identified some dominant species that disproportionally contribute to forest AGB with 1.5% of recorded species accounting for over 50% of the stock of AGB. Consequently, focusing on large trees and dominant species provides precise information on the whole forest stand. This offers new perspectives for understanding the functioning of tropical forests and opens new doors for the development of innovative monitoring strategies.

The complexity of analyzing and predicting smoke plumes that originate from forest fire events and impact populated regions of southern Ontario motivates the innovative application of analytical techniques including trajectory–based receptor modeling for spatial source apportionment of the observed near–real–time particulate matter (PM) impacts. PM2.5 was selected as an indicator of a pollutant emitted by fires that could be transported over long distances (when entrained into the transport layer above the planetary boundary layer (PBL), and subject to sink and transformation processes) and be monitored using the existing air quality monitoring network. The source term modeling technique of simplified Quantitative Transport Bias Analysis (sQTBA) was applied to several summertime forest fire events to identify the locations of sources affecting air quality in Ontario during these events. Complementary techniques that helped to understand the movement of smoke plumes included satellite remote sensing of carbon monoxide and aerosols. All of these techniques, along with meteorological analysis, jointly provide a means of identifying the forest fire events that resulted in noticeably higher pollutant levels in Ontario. Specifically, three forest fire events in July of 2011, 2012 and 2013 were analyzed, and source regions of near–real–time PM2.5 concentrations were revealed to be both within Ontario and across northern Canada from Quebec to Yukon. The sQTBA was found to successfully identify the relative importance of various source regions contributing plumes from forest fires and non–wildfire related sources that caused higher pollutant levels that were measured in Ontario. The use of near–real–time PM2.5 data in this study facilitates the identification of the exact periods with high pollution impacts across multiple receptor sites, thus improving the overall quality of the analyses. This work shows how trajectory–based receptor models can be integrated with meteorological analyses for thorough source apportionment of wildfire–related pollution events.

Ce numéro d’Innovations Agronomiques rassemble les présentations du colloque « Adaptation des forêts méditerranéennes aux changements climatiques » qui s'est tenu en Avignon le 20 novembre 2015. | National audience | In July 2015, a prospective workshop gathered ONF engineers and INRA/EFPA researchers, for thinking together about the adaptation levers that could be operated in forest management. This workshop focused on both silvicultural pathways (stand level), and management planning (level of the forest planning unit, region or the whole public forest resource). Foresters addressed their practical questions to researchers that selected scientific results providing knowledge to answer these issues. A project emerged from this discussion, consisting in i) designing diverse innovative management options, helped by modelling tools, and ii) in testing them on a significant part of the managed forested area, in the framework of a new monitoring and scientific exploitation system. | Dans le cadre d’un séminaire prospectif qui s’est tenu en juillet 2015, des ingénieurs de l’ONF et des chercheurs du Département EFPA ont réfléchi ensemble sur les leviers d’adaptation sur lesquels la gestion forestière pouvait agir. La discussion a porté tant sur les actions de sylviculture à l’échelle du peuplement, que sur les démarches de planification forestière aux échelles du massif, de la région ou de l’ensemble de la ressource. Face à l’exposé des questions de gestion, les chercheurs ont sélectionné des résultats scientifiques apportant des éléments de réponse. S’est dégagé de la discussion le projet de s’appuyer sur la modélisation pour concevoir des modalités de gestion innovantes diversifiées, et tester leur mise en œuvre sur une partie significative du domaine géré, dans un dispositif cohérent et organisé de suivi et d’exploitation scientifique des résultats .

This paper describes a detailed study of stump harvesting in Lamloch Forest in north Dumfries and Galloway from 2010 to 2014. The study explored both the nature and extent of soil disturbance resulting from stump harvesting using a variety of standard and innovative techniques. Stump harvesting disturbance was compared with that of other forestry practices. To complement the two-dimensional and subjective nature of visual assessment techniques, a radiometric approach was adopted, utilising residual Chernobyl 137Cs fallout to determine the degree of soil mixing. To support bulk density measurements, micromorphological analyses of soil thin sections were carried out to investigate the impact of compressive force on pore space. Low-cost tracer devices were deployed in the soil around stumps prior to extraction to permit the monitoring of soil lateral movement during stump extraction.  The study showed that stump harvesting followed by restock, when carried out under current guidelines, disturbed around five times the volume of soil compared to that disturbed by trench mounding. Stump harvesting also resulted in a net reduction in soil bulk density. Suggestions for modification of stump harvesting operations are made to reduce soil disturbance, including avoiding raking over the site following stump harvesting which is estimated to add a further 10% to the volume of soil disturbed.