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There is considerable interest in understanding the repercussions of compaction and organic matter removal on soil quality and forest productivity. However, long-term field trials examining the effects of machinery and forest biomass removal on soil quality and stand regeneration are scarce. We present 20-31 years of tree growth results from four unique stump removal field trials. Each site had both treatments with varying amounts of organic matter removal (from tree stem harvesting to removal of tree stumps to loss of roots) and treatments with different levels of compaction due to site preparation machinery. Tree heights among the different treatments at midrotation were the same or taller than those with minimal organic matter removal and compaction. However, when stand development was evaluated using the quantity of tree volume for the given number of trees planted, treatment effects were clearly evident; tree volumes were significantly lower in compacted treatments, whereas organic matter removal did not appear to effect stand production. Although the sites were not directly comparable, when combined, the field trials provide insights to the possible implications of forest biomass harvesting on stand regeneration and overall forest soil quality. Key words: forest soil quality, compaction, organic matter removal, stumping, root rot. La comprehension des repercussions de la compaction et du prelevement de la matiere organique sur la qualite des sols et la productivite de la foret suscite un interet considerable. Cependant, il y a peu d'experiences a long terme sur le terrain qui portent sur les effets de la machinerie et du prelevement de la biomasse sur la qualite du sol et la regeneration des peuplements. Nous presentons des resultats de croissance des arbres provenant de quatre essais experimentaux particuliers 20 a 31 ans apres un dessouchage. Des traitements consistant a enlever differentes quantites de matiere organique (integrant successivement la recolte du tronc des arbres, le dessouchage et l'elimination des racines) ont ete appliques dans chacun des sites qui avaient aussi subis differents degres de compaction du sol par la machinerie utilisee pour la preparation du site. A mi-rotation la hauteur des arbres etait semblable dans les differents traitements ou plus grande que dans le traitement ou il y avait eu le minimum de prelevement de matiere organique et de compaction du sol. Cependant, lorsque le developpement du peuplement etait evalue en utilisant le volume des arbres pour un nombre donne d'arbres plantes, l'effet des traitements etait nettement visible : le volume des arbres etait significativement plus faible dans les traitements ou le sol avait ete compacte tandis que le prelevement de la matiere organique ne semblait pas avoir d'effet sur la production du peuplement. Bien que les sites ne soient pas directement comparables, lorsqu'ils sont combines les essais experimentaux donnent un apercu des consequences potentielles de la recolte de la biomasse forestiere sur la regeneration des peuplements et la qualite generale des sols forestiers. [Traduit par la Redaction] Mots-cles: qualite des sols forestiers, compaction, prelevement de la matiere organique, dessouchage, carie de racines., 1. Introduction Mechanization of the forest industry in North America increased through the 1940s, and this prompted a growing concern on the impacts of harvesting techniques on forest soil quality. [...]

The growing demand for bioenergy feedstock from forest harvest residues is generating concerns about the potential loss of site productivity through nutrient removal. We used tree-level national biomass equations and a national database of forest plots to develop stand-level biomass equations for the different tree components of 30 major forest tree species found in Canada using basal area as the independent variable. We have also compiled more than 12 800 nutrient concentration values for different components of Canadian tree species from existing databases and the literature. Uncertainties were propagated across biomass equations and through conversion of nutrient concentrations to nutrient contents. Most of the uncertainty in nutrient contents estimates was found to be among the nutrient concentration measurements. The greatest levels of uncertainty were for estimates of phosphorus in woody components and of calcium in foliage. Grouping species into genera gave only a minor loss of precision. The coupling of biomass equations and nutrient concentration data can be used to provide first-order estimates of biomass and nutrients exported by tree component and species when harvesting any commercial stand in Canada. However, the associated uncertainties are important enough to warrant their inclusion in decision making. Resume: La demande croissante pour les residus de coupe a des fins de bioenergie genere des preoccupations de perte de productivite suite a l'exportation d'elements nutritifs. Nous avons developpe des equations allometriques de biomasse a l'echelle du peuplement pour 30 especes d'arbre dominantes de la foret canadienne utilisant la surface terriere comme variable independante, a partir d'equations nationales de biomasse a l'echelle de l'arbre et de l'information provenant d'un inventaire national de parcelles forestieres. Nous avons aussi compile plus de 12 800 valeurs de concentrations de nutriments pour diverses composantes d'arbre et d'especes qui provenaient de bases de donnees existantes et de la litterature. L'incertitude a ete propagee dans les equations allometriques et au travers de la transformation des concentrations de nutriments en contenus. La plupart des incertitudes se retrouvent au niveau des mesures de concentrations de nutriments. Ce sont les estimes du phosphore dans les compartiments ligneux ainsi que ceux du calcium dans le feuillage qui sont les plus incertains. Le regroupement des especes par genre n'a genere qu'une faible perte de precision. Le couplage des equations de biomasse et des mesures de concentrations en nutriments permet d'estimer les quantites de biomasse et de nutriments par composante d'arbre et par espece exportees des peuplements commerciaux lors de leur recolte. Cependant, l'incertitude sur ces estimes est suffisamment importante pour necessiter sa prise en compte pour les prises de decision., Introduction The increasing use of forest biomass as energy feedstock raises concerns over the sustainability of this practice because removing branches and foliage from sites can more than double nutrient [...]

Concerns about climate change and the desire to develop a domestic, renewable energy source are increasing the interest in forest biomass extraction, especially in the form of logging residues, i.e., tree tops and branches. We reviewed the literature to determine the site and soil conditions under which removal of logging residues along with the stem (i.e., whole-tree harvesting), especially at clearcut, results in negative impacts on soil productivity compared with conventional stem-only harvesting in boreal and temperate forests. Negative impacts of biomass harvesting on soil nutrient pools (e.g., nitrogen, phosphorus and base cations) and soil acid-base status are more frequent in the forest floor than in the mineral soil. In the first years post-harvest, however, biomass harvesting has the greatest potential to influence tree survival and growth, either positively or negatively, through its effects on microclimate and competing vegetation. Later in the rotation, impaired nitrogen and (or) phosphorus nutrition on whole-tree harvested sites has been shown to reduce tree growth for at least 20 years in some stands. Biomass removal can also reduce the concentrations of base cations in soils and foliage, but this has not, to date, been shown to affect tree productivity. There are no consistent, unequivocal and universal effects of forest biomass harvesting on soil productivity. However, climate and microclimate, mineral soil texture and organic C content, the capacity of the soil to provide base cations and phosphorus, and tree species autecology appear to be critical determinants of site sensitivity to biomass harvesting. Rigorous, long-term experiments that follow stand development through a rotation will facilitate the identification of categories of site or stand conditions under which negative impacts of biomass harvesting are likely. Key words: forest biomass, whole-tree harvesting, soil productivity, tree nutrition, stand productivity. Les preoccupations au sujet des changements climatiques et la volonte de developper des sources d'energie domestique renouvelable augmentent l'interet pour l'extraction de la biomasse forestiere, surtout sous la forme de residus de coupe, c.-a-d., les cimes et les branches des arbres. Les auteurs ont conduit une revue de litterature pour determiner les conditions de site et de sol pour lesquelles l'enlevement des residus de coupe en plus de la tige (c.-a-d., la coupe par arbre entier ), surtout lors de coupes a blanc, conduit a des impacts negatifs sur la productivite des sols comparativement a la recolte conventionnelle du tronc seulement, en forets boreales et temperees. Les impacts negatifs de la recolte de la biomasse sur les reserves du sol en nutriments (p. ex. azote, phosphore et cations basiques) et sur le statut acidite-alcalinite apparaissent plus frequents dans l'humus que dans le sol mineral. Cependant, au cours des premieres annees suivant la recolte, le prelevement de la biomasse montre le plus fort potentiel pour influencer la survie des arbres et leur croissance, soit positivement soit negativement, par ses effets sur le microclimat et la vegetation competitrice. Plus tard dans la revolution, on observe que pour certains peuplements, une nutrition amoindrie en azote et (ou) phosphore sur les sites avec coupe par arbre entier reduit la croissance des arbres pendant au moins 20 ans. Le prelevement de la biomasse peut egalement reduire les teneurs en cations basiques dans les sols et le feuillage, mais ceci ne semble pas se traduire en effet sur la productivite. Il n'y a pas d'effets non equivoques et universels de la recolte de la biomasse sur la productivite des sols. Cependant, le climat et le microclimat, la granulometrie du sol, sa teneur en C organique, sa capacite a fournir les cations basiques et le phosphore, ainsi que l'autecologie des especes semblent constituer des determinants importants de la sensibilite des sites a la recolte de la biomasse. Des experiences rigoureuses, conduites a long terme pour suivre le developpement des peuplements tout au long de la revolution, faciliteront l'identification des categories de sites ou les conditions des peuplements pour lesquels des impacts negatifs sont susceptibles de se developper. [Traduit par la Redaction], Introduction Biomass from forests and byproducts from the manufacturing of traditional forest products are increasingly used to generate a range of bioproducts, of which bioenergy is currently the most common. [...]

Abstract: The USDA Forest Service, the Canadian Forest Service, and US and Canadian forest products industries are committed to the principles of sustainable forestry with a major focus on protecting [...]

Industrial emissions in the Athabasca Oil Sands Region (AOSR), Alberta, Canada, have caused concerns about the effect of oil sands operations on the surrounding terrestrial environments, including jack pine (Pinus banksiana Lamb.) stands. We collected jack pine needles from 19 sites in the AOSR (13-128 km from main operations) for foliar chemical analyses to investigate the environmental impact on jack pine. Pine needles from three age classes, the current annual growth (CAG, 2011), one year and two year old pine needles, were collected. Samples were analyzed for total carbon (TC), nitrogen (TN), and sulfur (TS), inorganic S (SO4-S), base cations (Ca, Mg, Na), and other elements (B, Cu, Fe, Mn, P, Zn); CAG needles were also analyzed for their nitrogen and carbon isotopic compositions. Only TN, TS, Ca, B, Zn, and Fe contents showed weak but significant increases with proximity to the major oil sands operations. C and N isotopic compositions showed no trend with distance or TC and TN contents. Total S contents in CAG of pine foliage increased significantly with proximity to the main industrial operation while foliar inorganic S to organic S ratios (SO4-S/Sorg) ranged consistently between 0.13 and 0.32, indicating low to moderately high S loading. Hence, this study suggests some evidence of uptake of S emissions in close proximity to anthropogenic sources, although the reported values have not reached a level of environmental concern. [ABSTRACT FROM AUTHOR]

Ref.: Can. J. For. Res. 43(7): 599-608. A mistake was made when the nutrient concentration values for Douglas-fir (Pseudotsuga menziesii) were copied to Table 1 in the original publication. The [...]