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Currently, there are uncertainties regarding the impacts and (or) efficacy of biomass harvesting and silvicultural practices on stand production on coarse-textured boreal soils. Replicated factorial field experiments examining effects of complete vegetation control (repeated glyphosate application) following operational stem-only harvest with disc trenching ([SO.sub.T]), operational whole-tree harvest with ([WT.sub.T]) and without (WT) disc trenching, and whole-tree harvest with complete forest floor removal by blading ([WT.sub.B]) and blading followed by compaction ([WT.sub.BC]) were installed on four sandy northern Ontario jack pine (Pinus banksiana Lamb.) sites. Over 20 years, [WT.sub.B] improved planted- tree survival but decreased longer term stand productivity in comparison with other harvest intensity - soil disturbance treatments. Vegetation control improved tree growth and stand productivity initially, but over time, benefits declined substantially. [SO.sub.T]and WTt had similar impacts on stand production. Disc trenching improved initial planted-tree growth ([WT.sub.T] vs. WT), particularly without vegetation control. Jack pine natural regeneration was greatest with [SO.sub.T], accounting for 25% of stand biomass at year 20. Stand structure effects included increased size inequality of naturals with [WT.sub.B] and reduced size inequality and asymmetry of naturals with vegetation control. Overall, impacts of forest floor removal and natural regeneration on stand development have become increasingly important over time compared with those of vegetation control. Key words: organic matter removal, herbicide, productivity and structure, planting, natural regeneration. A l'heure actuelle, il existe des incertitudes concernant les impacts ou l'efficacite de la recolte de la biomasse et des pratiques sylvicoles sur la production des peuplements etablis sur des sols boreaux a texture grossiere. Nous avons realise des experiences factorielles repetees sur le terrain pour etudier les effets de la maitrise complete de la vegetation (application repetee de glyphosate) a la suite d'une recolte operationnelle par tronc entier avec scarifiage a disque ([TE.sub.S]), d'une recolte operationnelle par arbre entier avec ([AE.sub.S]) ou sans (AE) scarifiage a disque, d'une recolte par arbre entier avec enlevement complet de la couverture morte a l'aide d'un bouteur ([AE.sub.B]) et d'un bouteur suivi de la compaction du sol ([AE.sub.BC]). Ces traitements ont ete appliques sur quatre stations sableuses dominees par le pin gris (Pinus banksiana Lamb.) dans le nord de l'Ontario. Apres plus de 20 ans, la survie des arbres plantes a ete amelioree par le traitement AEB, qui a toutefois diminue la productivite du peuplement a long terme comparativement aux autres traitements impliquant l'intensite de la recolte et la perturbation du sol. La maitrise de la vegetation a initialement ameliore la croissance des arbres et la productivite du peuplement, mais ces gains ont substantiellement diminue avec le temps. Les traitements TES et AES ont produit des impacts semblables sur la production du peuplement. Le scarifiage a disque a ameliore la croissance initiale des arbres plantes ([AE.sub.S] vs AE), particulierement quand il n'y avait pas de maitrise de la vegetation. La regeneration naturelle de pin gris etait plus abondante dans le traitement [TE.sub.S], ce qui correspondait a 25 % de la biomasse du peuplement a 20 ans. Les effets de la structure du peuplement incluaient une augmentation de l'heterogeneite de la taille de la regeneration naturelle dans le traitement AEB et une reduction de l'heterogeneite de la taille et de l'asymetrie de la regeneration naturelle quand la vegetation etait maitrisee. Dans l'ensemble, l'importance des impacts de l'enlevement de la couverture morte et de la regeneration naturelle sur le developpement des peuplements a augmente avec le temps comparativement aux impacts de la maitrise de la vegetation. [Traduit par la Redaction] Mots-cles: enlevement de la matiere organique, herbicide, productivite et structure, plantation, regeneration naturelle., Introduction In many regions, including the boreal forest of Canada, forest biomass harvesting and intensive silviculture programs are now being used to increase fibre utilization and future stand production (Thiffault [...]

Abstract: To meet the demand for more and larger tallgrass prairie restorations, seed is frequently collected en-masse from remnant native plant populations. Overharvesting of seed may lead to population extinctions, [...]

The evaluation of the forage quality nutritive value and biomass usually takes multiple harvests and is considered time consuming, labor intensive, and expensive. The use of sensors to evaluate different forage traits has been proposed as a method to alleviate this problem. However, most analytical techniques involve the use of traditional linear methods for prediction, but prediction models can still be improved with the use of nonlinear methods. Thus, the objectives of this study are twofold: (i) to evaluate the performance of different prediction methodologies in important forage agronomic traits; and (ii) to evaluate the impact of sensor variables on predictive model performance in the different methods. The nondestructive multisensor system that accommodates spectral, ultrasonic, and laser data was tested on a bermudagrass [Cynodon dactylon (L.) Pers] experiment. Partial least square regression, ridge regression, support vector machine with radial kernel (SVM), and random forest were tested for the prediction performance. The random forest had the best performance, with 0.89 correlation for dry matter yield trait prediction, whereas SVM performed best in the remaining 15 traits, with correlation ranging from 0.72 to 0.95. Besides the prediction performance of statistical models, this study also provided some insight about the importance of variables by removing variables and reevaluating the model performance in dry matter yield. Overall, most of the traits in this study could be reliably predicted by the SVM. The multisensor system can facilitate the measurement of agriculturally important traits in a time-, labor- and cost-efficient way. [ABSTRACT FROM AUTHOR]

Forests in southern Italy are mainly located in mountainous areas, where ground-based extraction is still the most common harvesting technique. In particular, 60% of southern Italy's forests are on slopes with an angle of inclination between 20-60%. The low level of mechanization in forest operations is due to the difficult site conditions, as well as the small-scale characteristics of both the forest owners and the harvesting contractors. The most common work method uses chainsaws to fell the trees, and animals or farm tractors equipped with winches for bunching and extraction. This study assesses the productivity and cost effectiveness of extraction with a purpose-built John Deere 548H skidder, including a comparison of winch and grapple configurations. The results show that the productivity of skidding depends on distance as well as the condition of the skid trail. The number of trees per cycle and volume of each load also had a clear effect. While large purpose-built skidders represent a significant investment, this study demonstrates that the productivity is very high compared to traditional extraction methods and the resulting extraction costs are very competitive. As such, this study indicates that, over time, southern Italian harvesting operations should invest in purpose-built harvesting systems. [ABSTRACT FROM AUTHOR]

Copyright of Forestry Chronicle is the property of Canadian Institute of Forestry and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Harvesting traffic may alter soil properties and reduce forest productivity if soil disturbances are not mitigated. Logging operations were conducted during high soil moisture conditions on the South Carolina, USA coast to salvage timber and reduce wildfire potential following Hurricane Hugo in 1989. Long term study sites were established on wet pine flats to evaluate effects of primary skid trails and site preparation on soil properties and loblolly pine productivity. The experiment was analyzed as a split-plot within an unbalanced randomized complete block design having 12 blocks, two levels of traffic (primary skid trail (On), no obvious traffic (Off)) and four levels of site preparation (bedding (Bed), disking with bedding (D/B), disking (Disk), no site preparation (None)). Remeasurement of the study was conducted in 2015 at 25 years after salvage logging (stand age 23 years). Bed and D/B treatments had greater saturated hydraulic conductivity (p = 0.0567) and macroporosity (p = 0.0071) and lower bulk density (p = 0.0226) values than Disk and None treatments. Macroporosity benefits were evident two years after site preparation installation, but bulk density and saturated hydraulic conductivity were not, suggesting these two measurements were affected over time by differences in rooting activity influenced by initial aeration benefits. Depth to iron depletion (p = 0.0055) was significantly greater and soil carbon (p < 0.0001) was significantly lower in Bed and D/B treatments due to bed elevation above the water table and improved drainage. This implies greater aeration for roots, but trade-offs in above-ground biomass and soil carbon storage. However, above and below ground carbon differences balanced one another between treatments so that combined carbon storage in soil and above ground loblolly pine biomass was not significantly different by site preparation treatment (p = 0.1127). Bed and D/B resulted in approximately double the stand biomass (p < 0.0001) and stand density (p < 0.0001) than Disk and None. Bed and D/B generally created more favorable soil properties and enhanced long term loblolly pine stand productivity. Differences in soil properties and stand productivity between traffic levels, with and without site preparation, were negligible suggesting natural soil recovery mechanisms were mitigated effects of wet site harvesting over 25 years. [ABSTRACT FROM AUTHOR]

Technical product harvesting (TEPHA) is a newly developing interdisciplinary approach in which bio-based production is investigated from a technical and ecological perspective. Society's demand for ecologically produced and sustainably operable goods is a key driver for the substitution of conventional materials like metals or plastics through bio-based alternatives. Technical product harvesting of near net shape grown components describes the use of suitable biomass for the production of technical products through influencing the natural shape of plants during their growth period. The use of natural materials may show positive effects on the amount of non-renewable resource consumption. This also increases the product recyclability at the end of its life cycle. Furthermore, through the near net shape growth of biomass, production steps can be reduced. As a consequence such approaches may save energy and the needed resources like crude oil, coal or gas. The derived near net shape grown components are not only considered beneficial from an environmental point of view. They can also have mechanical advantages through an intrinsic topology optimization in contrast to common natural materials, which are influenced in their shape after harvesting. In order to prove these benefits a comprehensive, interdisciplinary scientific strategy is needed. Here, both mechanical investigations and life cycle assessment as a method of environmental evaluation are used. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Concern over global environmental change and associated uncertainty has given rise to greater emphasis on fostering resilience through forest management. We examined the impact of standard silvicultural systems (including clearcutting, shelterwood, and selection) compared with unharvested controls on tree functional identity and functional diversity in three forest types distributed across the northeastern United States. Sites included the Argonne, Bartlett, and Penobscot Experimental Forests located in Wisconsin, New Hampshire, and Maine, respectively. We quantified functional trait means for leaf mass per area, specific gravity, maximum height, height achieved at 20 years, seed mass, drought tolerance, shade tolerance, and flood tolerance as well as standard functional diversity measures from standing biomass reconstructed at the beginning and end of a 20-year study period using increment cores and historic inventory data. As expected, functional identity differed between harvest methods with means for plant traits associated with later stages of succession (e.g. shade tolerance) increasing in stands managed with selection systems. Opposite trends occurred with greater canopy disturbance, and functional diversity indices remained stable over time in the absence of disturbance. Estimates of functional diversity and functional identity hold promise as important approaches for evaluating outcomes of forest management, particularly as the connections among functional diversity, delivery of ecosystem services, and ecosystem resilience are further developed. [ABSTRACT FROM AUTHOR]

Stover, the material remaining after harvesting corn (Zea mays L.) grain, may be removed for many purposes, but this material is also crucial for protecting and enriching soil properties. This research was conducted on sites located on working farms to assess the impact of three levels of harvest: (i) Grain only, (ii) Grain+Cob and (iii) grain and all stover, which includes cobs (Grain+Stover) on several soil properties related to soil organic carbon (SOC) pools, dry aggregate-size distribution (DASD), fraction of dry aggregates remaining stable in water (ASW) and unconfined field soil hydraulic properties including infiltration rate (i), sorptivity (S) and characteristic mean pore size (λm). The Chokio site on a clay loam soil was managed in a corn/soybean (Glycine max L. [Merr.])/wheat (Triticum aestivum L.) rotation with chisel plow tillage to 18 cm. The Clontarf site on a sandy loam soil was managed in a corn/bean (Phaseolus vulgaris L.) rotation with deep disk tillage to 36 cm. The Donnelly site on a clay loam soil, was managed in a corn/soybean rotation with strip tillage to ⩽13 cm. At the Chokio and Clontarf sites, managed with 18- or 36-cm tillage, respectively, SOC, DASD and hydraulic properties decreased over time in all treatments. At the Donnelly site managed with <13-cm tillage, the Grain treatment maintained SOC throughout the profile, favorable DASD and hydrologic properties, but harvesting cobs or all stover undermined these positive attributes. Results of this study suggested that to protect soil properties from degradation all stover needs to be returned. [ABSTRACT FROM AUTHOR]

Copyright of Canadian Journal of Forest Research is the property of Canadian Science Publishing and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Kiwifruit (Actinidia deliciosa) are capable of long term storage only if carefully protected against deterioration prior to and during storage. They are harvested when mature but unripe and must ripen before eating. They are extremely sensitive to ethylene gas, which causes rapid flesh softening during storage, starch depletions to reduced sugars, increased susceptibility to spread of fruit rotting organisms and physiological breakdown. Hardy kiwifruit/Baby kiwi (Actinidia arguta) have smooth, edible skins and are smaller in size than 'Hayward' kiwifruit. Unlike A. deliciosa, baby kiwi fruits are very sensitive to dryness because of their smooth peels that lack hair. This phenotype characteristic is the main reason for the short-storage time and fast loss of postharvest quality. Fruits are not picked vine ripe, as they would be too soft to package and ship, instead they are picked when physiologically mature and firm, and are stored under refrigeration (0°C, 90-95% RH). Limited information exists regarding the ripening physiology of hardy kiwifruit or the ideal packaging and storage conditions for optimum quality, storage and shelf life. The objectives of this paper is to integrate existing knowledge and findings about applying technologies developed to suppress ethylene content and its effects degrading the kiwifruit post-harvest by applying 1-methylcyclopropene and periodically reviewing its effects and changes in kiwifruit quality, thereby improving storage technologies and extend the shelf life. The paper is an overview of how to optimize storage technologies of kiwifruit, managing fruit ripening by controlling naturally occurring ethylene during storage for optimal market value and more efficient harvest management, while maintaining excellent quality fruit and reduce losses and findings reveal the importance for assessing the marketing performance of the retail wine stores and the limits that generated lack of adoption on a large scale. [ABSTRACT FROM AUTHOR]

1. Concerns about loss of biodiversity and structural complexity in managed forests have recently increased and led to the development of new management strategies focused on restoring or maintaining ecosystem functions while also providing wood outputs. Variable retention harvest (VRH) systems, in which mature overstorey trees are retained in various spatial arrangements across harvested areas, represent one potential approach to this problem. However, long-term evaluations of the effectiveness of this strategy at sustaining plant community composition are needed as this strategy is increasingly applied in managed forest landscapes throughout the world. 2. The forest ground layer plays a central role in forest ecosystem functioning, and we evaluated the long-term (11+ year) dynamics in ground-layer plant communities in response to VRH study in Pinus resinosa Aiton. forests. This large-scale, manipulative study included four overstorey (control, small gap-aggregated, large gap-aggregated and dispersed) and two understorey (ambient and reduced shrubs) treatments replicated four times in 16-ha stands. 3. Changes in ground-layer community composition were apparent 11 years following harvest, regardless of live-tree retention pattern. Richness and diversity increased and were driven by introduction and colonization of ruderal species, while forest interior species continued to persist across treatments. All life-forms responded positively to harvest with the exception of moss and clubmoss species. 4. The lack of effect of spatial pattern of retention on ground-layer plant communities was likely related to the presence of a dense and persistent shrub layer, a result of decades of fire suppression. In particular, the greatest responses to overstorey retention pattern occurred in areas receiving shrub reduction treatments, indicating this recalcitrant layer likely filtered response to retention pattern. 5. Synthesis and applications. Overall, this work highlights flexibility in choosing a variable retention harvest approach when sustaining ground-layer plant community diversity and composition are goals, but altered disturbance regimes (e.g. fire suppression, timber harvesting) that have facilitated the presence or formation of recalcitrant understories, need to be considered. The legacy effects of historical land use and alterations to natural disturbance regimes on the understorey in northern temperate forests are of equal, if not greater, importance to overstorey retention patterns in eliciting desired responses to variable retention harvest and need to be more carefully considered in future applications of this method. [ABSTRACT FROM AUTHOR]

A response to the commentary on the article "No harvest was reaped: demographic and climatic factors in the decline of the Neo-Assyrian Empire" is presented. The authors note that the premise of their original paper and its purpose has been misread and misjudged. They also stresses that the larger point of their article has been missed out where the proxy records indicate a shift towards drier conditions.

Copyright of Revista de Economia e Sociologia Rural is the property of Sociedade Brasileira de Economia e Sociologia Rural and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this article the authors present an example of an agricultural farm that produces wheat corn, soya, and other plants. After harvesting granular products, large amounts of plant remains (biomass) are used as biofuel at the boiler in order to heat the agricultural farm. We present the results of research of energetic characteristics and boiler efficiency of thermal power of 750 kW that serves for farm heating. At the boiler biomass is burned and the boiler is adapted for burning dead animals and other remains using liquid petroleum gas) as additional fuel. Biomass that is used as biofuel is wheat or soya straw. Using the straw as an alternative biofuel significant cuts are achieved on conventional fuel LPG. The annual expense of soya straw is 1,700 tons, from an area of 565 ha, or 1,970tons of wheat straw from an area of 660 ha. Expenses of gathering, transport and storage are approximately 0.021 €/kg. Economic validity of using biomass as an energent had been proven by the fact that using straw is six times cheaper than using LPG. The ecological significance of using the biomass is investigated. [ABSTRACT FROM PUBLISHER]

Industrial forestry can negatively affect biodiversity, and rare or endangered species are particularly vulnerable. Boreal felt lichen (Erioderma pedicellatum (Hue) P.M.J ∅ rg.) is a globally critically endangered species, and its population in Nova Scotia has been reduced through harvesting of its host tree balsam fir (Abies balsamea (L.) Mill.). We hypothesized that forest harvesting adjacent to and within the landscape of boreal felt lichen could increase the risk of mortality by negatively affecting microclimate of its habitat. Autologistic regression models were used to measure probability of mortality (death or disappearance) with harvesting history at the stand and landscape scales. Erioderma pedicellatum mortality and 17-year tree harvesting history derived from satellite data were used in the model. Modeling at the stand scale suggested that the probability of E. pedicellatum mortality increased as the area of tree harvesting increased. At the landscape scale, the model suggested that probability of E. pedicellatum mortality increased as the area of harvest within 500 m increased. Adjacent tree harvesting may increase solar radiation, wind, and temperature, which could have a negative effect on E. pedicellatum survival. We recommend maintaining uncut buffer zones around E. pedicellatum and limiting the size of harvest blocks and amount of harvesting in the landscape over a given time period to help conserve this endangered species. Resume: La foresterie industrielle peut avoir un impact negatif sur la biodiversite et les especes rares ou menacees sont particulierement vulnerables. L'erioderme boreal (Erioderma pedicellatum (Hue) P.M.J ∅ rg.), est une espece de lichen serieusement menacee partout dans le monde et sa population en Nouvelle-ecosse a ete reduite a cause de la recolte de son hote, le sapin baumier (Abies balsamea (L.) Mill.). Nous avons formule l'hypothese que l'exploitation forestiere dans les limites ou a proximite du paysage occupe par l'erioderme pourrait accroitre les risques de mortalite a cause de l'impact negatif sur le microclimat de son habitat. Des modeles de regression autologistique ont ete utilises pour mesurer la probabilite de la mortalite (mort ou disparition) selon l'historique de recolte a l'echelle du peuplement et du paysage. La mortalite de l'erioderme et l'historique des coupes sur une periode de 17 annees derive de donnees satellitaires ont ete utilises dans le modele. La modelisation a l'echelle du peuplement indique que la probabilite de la mortalite de l'erioderme augmente en fonction de la superficie recoltee. A l'echelle du paysage, le modele indique que la probabilite de la mortalite de l'erioderme augmente avec l'augmentation de la superficie recoltee a moins de 500 m. La recolte des arbres adjacents peut augmenter le rayonnement solaire, les vents et la temperature, ce qui pourrait avoir un effet negatif sur la survie de l'erioderme. Nous recommandons de conserver des zones tampons exemptes de coupe autour de l'erioderme et de limiter la taille des blocs de coupe et le nombre de coupes dans le paysage pendant une periode temps donnee pour aider a conserver cette espece menacee. [Traduit par la Redaction], Introduction Industrial forestry impacts to biodiversity have been well documented. Forest structural changes as a result of intensive forestry can result in loss of habitat such as snags and coarse [...]

Stump and root wood procurement has increased in the twenty-first century in Finland. Potential amounts of techno-economically harvestable stump wood account for 2–11 TWh, depending on the cost-efficiency of the stump procurement. For increasing stump wood consumption of energy plants lifting technology of stumps requires further development. In this research, three stump-lifting devices were compared. These devices were connected to human–machine systems which operated in similar study stands. Based on the machine, time, stand, cost and biomass data, productivity and cost-efficiency of the stump-lifting devices were determined in the work system study. The productivity of stump lifting was 16.4 m³ sob/process-hour (7.1 tD/process-hour) to the stumps with a diameter of 40 cm on sites processed using Terosa stump-lifting device and Hakkila's biomass model were used in the system. Further, the stump-lifting costs with Terosa were around 37% (sob/E0-hour) lower than those of Väkevä and Xteho. In this respect the machinery equipped with Terosa provides the cost-efficient stump-lifting system. Based on herein reported study, it can be stated that Terosa is a promising stump-lifting device that enables cost-efficient extraction of stump wood. [ABSTRACT FROM PUBLISHER]

Most cervid populations in Europe and North America are managed through selective harvesting, often with age- and sex-specific quotas, with a large influence on the population growth rate. Less well understood is how prevailing weather affects harvesting selectivity and off-take indirectly through changes in individual animal and hunter behavior. The behavior and movement patterns of hunters and their prey are expected to be influenced by weather conditions. Furthermore, habitat characteristics like habitat openness are also known to affect movement patterns and harvesting vulnerability, but how much such processes affect harvest composition has not been quantified. We use harvest data from red deer ( Cervus elaphus) to investigate how weather and habitat characteristics affect behavioral decisions of red deer and their hunters throughout the hunting season. More specifically, we look at how sex and age class, temperature, precipitation, moon phase, and day of week affect the probability of being harvested on farmland (open habitat), hunter effort, and the overall harvest numbers. Moon phase and day of week were the strongest predictors of hunter effort and harvest numbers, with higher effort during full moon and weekends, and higher numbers during full moon. In general, the effect of fall weather conditions and habitat characteristics on harvest effort and numbers varied through the season. Yearlings showed the highest variation in the probability of being harvested on farmland through the season, but there was no effect of sex. Our study is among the first to highlight that weather may affect harvesting patterns and off-take indirectly through animal and hunter behavior, but the interaction effects of weather and space use on hunter behavior are complicated, and seem less important than hunter preference and quotas in determining hunter selection and harvest off-take. The consideration of hunter behavior is therefore key when forming management rules for sustainable harvesting. [ABSTRACT FROM AUTHOR]

Modification of forest attributes and structural components like downed wood (DW) during forest harvest can lead to local species loss. Epixylic bryophytes have been proposed as good indicators of such changes. Unharvested control, variable canopy retention, and single pass harvest represent a gradient in forest harvest impact and can be used to test the response of epixylic bryophytes to different levels of environmental change. The objective of this study was to see if variable canopy retention attenuates environmental change associated with harvesting, consequently maintaining an epixylic community more similar to unharvested stands than single pass harvesting. Environmental conditions and DW characteristics were sampled on 225 DW pieces distributed in 45 permanent plots. Results showed that treatment affected epixylic richness through its impact on canopy openness and DW diameter and decomposition class. Fewer species were found in more open habitats and more species were found on bigger and more decomposed DW. Most epixylic species were more commonly found on the forest floor than on the DW. In conclusion, variable canopy retention harvest offered microclimatic conditions and DW availability and quality more suitable for epixylic species than single pass harvest, which was less suitable for epixylic species. Resume: La modification des attributs forestiers et des composantes structurales tel les debris ligneux grossiers (DLG) peut entrainer la perte locale d'especes associees. Les bryophytes epixyliques ont ete suggerees comme de bons indicateurs de ces changements. Un temoin non perturbe, une coupe a retention variable de canopee et une coupe totale constituent un gradient d'impact des activites forestieres et sont utilises pour observer la reponse des epixyliques aux niveaux de perturbation. L'objectif de cette etude est de voir si la retention variable de canopee attenue les changements micro environnementaux et la destruction des DLG associee avec la recolte maintenant ainsi une riche communaute d'epixyliques. Les resultats montrent que le traitement influence la richesse des epixyliques a travers son effet sur l'ouverture de la canopee, le diametre moyen et la classe de decomposition. Moins d'especes sont retrouvees dans les habitats ouverts et plus d'especes sont re-trouvees sur les gros DLG bien decomposes. La plupart des epixyliques sont plus communement retrouvees au sol que sur les DLG. La coupe totale est le traitement le moins propice a la colonisation par les epixyliques alors que la retention variable de canopee offre le microclimat et une disponibilite de DLG de qualite propice a la colonisation par les epixyliques., Introduction Forest harvest alters biodiversity by changing forest attributes and structural components like downed wood (DW) on which many organisms depend for food and shelter (Harmon et al. 1986). Modification [...]

Harvesting of medicinal plants from wild populations is increasing worldwide, however, studies on sustainable harvesting techniques are lacking. In this exploratory study, we investigated the impact of leaf harvesting on Rhododendron groenlandicum (Oeder) Kron & Judd, a North American temperate shrub, used traditionally as a medicinal plant by the Cree Nation. The species is widely distributed, but Crees are worried that commercial harvesting could threaten local plant populations. Our study was conducted near the Cree Nation of Mistissini (James Bay, Northern Quebec). Three leaf harvest regimes were tested in 2008 and 2009: no harvest, all leaves harvested, and only old leaves harvested; each treatment was performed on 30 plants. The harvesting of all leaves had a negative impact on stem elongation after the first harvest, while leaf production and stem radial growth decreased after the second harvest. Two-thirds of the plants also died following the second regime of harvesting all leaves. The harvesting of old leaves had no significant impact on growth, leaf production, or survival of R. groenlandicum, even after 2 years of harvest. These results lead to the conclusion that sustainable harvest of this species is possible, but further study is required to make definite recommendations. Key words: conservation, medicinal plant, sustainability, harvesting simulation, Cree Nation. La recolte de plantes medicinales provient surtout de populations sauvages et peu d'etudes existent sur leur durabilite. Nous examinons ici l'impact de la recolte sur Rhododendron groenlandicum (Oeder) Kron & Judd, un arbuste nord americain utilise par la Nation crie pour ses proprietes medicinales. Cette espece est deja recoltee commercialement au Quebec, ce qui pourrait menacer localement certaines populations : cela inquiete d' ailleurs la Nation crie. L'objectif de cette etude etait d' evaluer l' impact de la defoliation sur des plants de R. groenlandicum situees a proximite de Mistissini (Baie James, Quebec). Trois niveaux de recolte de feuilles ont ete appliques sur 30 plants chacun en 2008 et 2009 : aucune recolte, la recolte de toutes les feuilles et la recolte des vieilles feuilles seulement. Les resultats montrent que recolter toutes les feuilles a un impact negatif sur l' elongation des rameaux apres une seule recolte tandis que la croissance radiale et la production de feuilles diminuent apres deux recoltes consecutives. De plus, une mortalite importante des plants (deux tiers) est survenue apres la deuxieme recolte. La recolte des vieilles feuilles seulement n' a pas d' impact significatif sur la croissance et la survie, meme apres la deuxieme annee. Nos resultats indiquent que la recolte de cette plante serait soutenable, cependant d' autres etudes sont necessaires pour emettre des recommandations. Mots-cles : conservation, plantes medicinales, developpement durable, simulation de recolte, Nation crie. [Traduit par la Redaction], Introduction Medicinal plants are gaining popularity in industrial societies as alternative medicine, and their sales are increasing (Cavaliere et al. 2010). This accelerating interest may lead to overharvesting, which in [...]