No abstract

With a growing interest in the diversification (e.g., bioenergy, biochemicals) of the forest industry beyond the traditional product streams, concerns that higher harvest utilization levels may compromise site productivity have been heightened. This study reports on 15-year tree growth responses to varying levels of biomass removals conducted on four soil types: loamy tills, outwash sands, wet mineral, and peatlands. Experimental harvest treatments included stem-only, full-tree, full-tree chipping (a full-tree harvest with the roadside material chipped and returned to the site), and full-tree + bladed (a full-tree harvest followed by forest floor removal). Results indicated no significant effect on height growth on the loamy tills, a significant decline for the blading treatment on the sandy soils, and an increase when the blading treatment was applied to the peatland sites. At the stand level, better planted seedling survival and higher recruitment of naturals on the more extreme removal treatment (forest floor removal on sandy sites) tended to nullify any negative impacts identified in the individual-tree growth measurements. The more than doubling of the slash loading on the stem-only treatment plots compared with the full-tree plots did not result in differences in tree productivity levels between these two operational treatments. The stands, however, were just approaching crown closure by year 15, suggesting that ongoing monitoring will be required to confirm that the growth trajectories for the various harvest treatment -soil type combinations can be maintained.Résumé : Dans la mesure où l'industrie forestière est de plus en plus intéressée à diversifier ses activités (p. ex., bioénergie et produits biochimiques) au-delà de sa gamme traditionnelle de produits, les craintes que l'utilisation plus complète de la forêt compromette la productivité des stations augmentent. Cette étude rend compte des réactions en croissance des arbres, après 15 ans, à différents degrés de prélèvement de la biomasse sur quatre types de sol : till loameux, sable fluvio-glaciaire, sol minéral humide et tourbières. Les traitements expérimentaux d'exploitation incluaient tronc entier, arbre entier, copeaux d'arbres entiers (récolte d'arbres entiers mis en copeaux en bordure de route et redistribués sur le site), arbre entier + lame bineuse (récolte d'arbres entiers et enlèvement de la couverture morte). Les résultats ne révèlent aucun effet significatif sur la croissance en hauteur sur le till loameux, mais il y a une diminution importante avec le traitement arbre entier + lame bineuse sur les sols sablonneux et une augmentation avec le même traitement dans les tourbières. À l'échelle du peuplement, une meilleure survie des semis plantés et plus de recrues d'origine naturelle dans le traitement où l'enlèvement de la biomasse était le plus prononcé (enlèvement de la couverture morte sur les sols sablonneux) avaient tendance à annuler tous les impacts négatifs identifiés dans les mesures de croissance d'arbres individuels. Dans le trai...

S. 2009. Developing site disturbance standards in Ontario: Linking science to forest policy within an adaptive management framework. Can. J. Soil Sci. 89: 13Á23. In anticipation of the review and revision of Ontario's current site protection guidelines, a site disturbance task team was formed in 2004. Over the next two years, they conducted an extensive review of the scientific literature and existing guidelines from other jurisdictions, as well as engaging both forest industry partners and Ontario Ministry of Natural Resources (OMNR) field services personnel in a consensus building exercise (i.e., client survey, field tours, and formal workshops). The goal of their efforts was to develop a set of provincial-level site disturbance standards with metrics to be considered as part of Ontario's new stand/site guide scheduled for release in 2009 and implemented in the 2011 forest management plans. The process developed by the task team was a pro-active approach that engaged the end users of the product throughout the process and should provide stronger accountability to the public and increase competency in our practices. Setting the first iteration of a standard as a practical benchmark for rutting (depth 3 cm, length 4 m and cumulative limits for each harvest block Á 10% for clearcut and 2% for partial cut systems) will allow the forest industry to adapt to the approach relatively easily and provide a visual indicator of performance. It was stressed that there needs to be a rigorous effectiveness monitoring protocol based on objective-based silviculture that is integrated within an adaptive management framework. This, in turn, will provide local science and evidence to: (1) conduct a comprehensive evaluation to the effects and impacts of site disturbance, (2) provide a quantitative, results-based evaluation of the effectiveness of the proposed guidelines, and (3) increase core competency and performance with respect to silviculture effectiveness and the role of soil disturbance in meeting our forest management objectives. Without a strong commitment and linkage of compliance, effectiveness, and validation monitoring, Ontario's forest policy development will largely remain in a state of ''repeat or react'' rather than ''evaluate and adjust''.

. 2009. The influence of soil rutting severity on regeneration potential and seedling performance for black spruce-dominated peatlands. Can. J. Soil Sci. 89: 57Á66. Excessive rutting continues to be recorded in post-harvest compliance inspections in black spruce peatlands across Ontario. These qualitative, visual assessments, however, cannot provide the necessary data to determine a site disturbance threshold that is linked to poor regeneration and seedling growth. In an attempt to provide this quantitative link, harvested black spruce [Picea mariana (Mill.) B.S.P.] peatland sites were surveyed and divided into severely rutted (non-compliant), moderately rutted, and non-rutted (compliant) blocks. In 1995In , 2001In , and 2006, each block was assessed for areal extent of rutting, number of plantable spots, moisture status, planting medium, competition level, stand density, species composition, and black spruce seedling survival and growth. Black spruce seedling survival in the severely-rutted block was significantly lower when compared with either the moderately rutted or the non-rutted blocks. A derived seedling survival model identified moisture class as having the largest influence on the probability of seedling survival. In terms of seedling growth, however, it was the non-rutted blocks that had the poorest performance. Based on a canonical discriminant analysis (CDA), competition factors, particularly ericaceous shrub cover, were the most important microsite factors influencing black spruce seedling growth. Overall, the moderately rutted block generated conditions that resulted in high conifer recruitment and good seedling survival and growth. Although the inference space of the study is small, the results suggest that black spruce peatland sites may benefit from a moderate level of site disturbance caused during harvest operations.Key words: Rutting severity, black spruce peatlands, survival, growth, microsite assessment Morris, D. M., Mackereth, R. W., Duckert, D. R. et Hoepting, M. K. 2009. L'intensite´de l'ornie´rage et son incidence sur le potentiel de re´ge´ne´ration et la performance des plantules dans les tourbie`res a`e´pinette noire. Can. J. Soil Sci. 89: 57Á66. Dans les tourbie`res a`e´pinette noire de l'Ontario, les inspections de conformite´effectue´es apre`s la re´colte continuent de re´ve´ler un ornie´rage excessif. Ces e´valuations qualitatives, reposant sur un examen visuel, ne fournissent toutefois pas les donne´es essentielles qui permettraient d'e´tablir le degre´de perturbation a`partir duquel la foreˆt se re´ge´ne`re mal ou les plantules s'e´tablissent difficilement. Afin de combler cette lacune quantitative, les auteurs ont inspecte´des tourbie`res d'e´pinette noire [Picea mariana (Mill.) B.S.P.] apre`s leur exploitation et les ont se´pare´es en blocs selon l'ornie´rage (ornie´rage e´leve´ou nonconforme, ornie´rage mode´re´et aucun ornie´rage ou conformes). Chaque bloc a e´te´e´value´en 1995, 2001 et 2006 pour e´tablir l'ampleur de l'ornie´rage a`vol d'oiseau, le nombre de sites susc...