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Preindustrial forest composition for >180 000 km 2 throughout central and northeastern Ontario was recreated from Ontario Crown land survey notes and compared with existing forest composition derived from current Forest Resource Inventories (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009) in each of Site Regions 3E, 4E, and 5E. A validation analysis was performed using the Forest Resource Inventory data to test the assumption that sampling the land survey tree species composition along township boundaries is adequate in describing the composition of the whole forest. The majority of tree species in each of the three site regions validated successfully. A binary logistic regression model allowed birch genera to be classified at the species level to aid in the interpretation of survey notes. All analyses showed significant reductions in conifers (especially red pine (Pinus resinosa Ait.), white pine (Pinus strobus L.), and eastern larch (Larix laricina (Du Roi) K. Koch)) and significant increases in maple (Acer spp.), oak (Quercus spp.), white birch (Betula papyrifera Marsh.), and poplar (Populus spp.).Résumé : La composition forestière préindustrielle d'une aire de plus de 180 000 km 2 dans le centre et le nord-est de l'Ontario a été reconstituée à partir de notes d'inventaire des terres publiques de l'Ontario (1816-1955) et comparée à la composition forestière actuelle déterminée à partir des inventaires des ressources forestières (1998-2009) dans chacune des régions écologiques 3E, 4E et 5E. Une analyse de validation a été effectuée avec des données de l'inventaire des ressources forestières pour tester l'hypothèse que l'échantillonnage de la composition forestière de l'inventaire des terres le long des limites de comté est adéquat pour décrire la composition de l'ensemble de la forêt. La majorité des espèces d'arbre dans chacune des trois régions écologiques ont été validés avec succès. Un modèle de régression logistique binaire a permis de classifier les bouleaux à l'espèce pour faciliter l'interprétation des notes d'inventaire. Toutes les analyses ont montré qu'il y avait une réduction significative des conifères (en particulier le pin rouge (Pinus resinosa Ait.), le pin blanc (Pinus strobus L.) et le mélèze laricin (Larix laricina (Du Roi) K. Koch)) et une augmentation significative des érables (Acer spp.), des chênes (Quercus spp.), du bouleau à papier (Betula papyrifera Marsh.) et des peupliers (Populus spp.).[Traduit par la Rédaction]

Northern white-cedar (eastern white cedar; Thuja occidentalis L.) is an important tree species in the northeastern United States and adjacent Canada, occurring both in pure stands and as a minor species in mixed stands of hardwoods or other softwoods. Yet practitioners have little and often contradictory information about cedar ecology and silviculture. In response to this information need, a group of university and government researchers in the United States and Canada embarked on more than a decade of collaborative research; this guide is a compilation of the knowledge generated by that effort. It includes an overview of the commodity and non-commodity values of cedar, silvics of cedar and companion species, descriptions of the cedar resource in the northeastern United States, Quebec, and Ontario, and silvicultural guidelines based on previously published literature and new studies of cedar regeneration, growth, mortality, site relationships, and responses to treatment. With generally slow growth and little to no ingrowth on most inventory plots in the region, silvicultural prescriptions that explicitly address cedar are warranted. Recommendations include retaining and releasing cedar in managed stands, as well as establishing and protecting advance cedar regeneration and residual trees during harvesting. Partial cutting (e.g., the selection or irregular shelterwood method) is suggested for regenerating stands with a component of cedar, though browsing by white-tailed deer (Odocoileus virginianus Zimmermann) may infl uence treatment outcomes and must be considered. Once established, cedar responds well to release and will benefi t from competition control and thinning. In mixedspecies stands, within-stand fl exibility of treatment is critical for maintaining cedar when other, more dominant species are driving silvicultural prescriptions at the stand level; a "micro-stand" approach in which pockets of cedar are identifi ed and managed is suggested.

Presettlement forest composition along a 278 km long transect through central Ontario was recreated from Ontario land survey notes (1857) and compared with existing forest composition as derived from Forest Resource Inventories (1981-1995). Trends through time were analyzed by means of detrended correspondence analysis and univariate statistics (paired t tests and Wilcoxon matched-pair signed-ranks tests). Ordinations based on the first tree taxon listed in a stand and on all tree taxa provided similar results. The eastern half of the transect was initially dominated by boreal conifers, whereas the western half supported stands typical of Ontario's Great Lakes - St. Lawrence (GLSL) region. Significant reductions of yellow birch (Betula alleghaniensis Britt.), balsam fir (Abies balsamea (L.) Mill.), and eastern white cedar (Thuja occidentalis L.) and significant increases of poplar (Populus spp.) and white birch (Betula papyrifera Marsh.) were observed within the boreal half. A significant reduction in eastern white cedar and an increase poplar were observed in the western half. Changes in the boreal region strongly support previous studies conducted over shorter time periods and may be attributed to clear-cut harvesting. The persistence of shade-tolerant hardwoods within the GLSL region can be attributed to the prevalence of small-scale disturbances associated with partial-cut harvesting systems.

Species composition estimated from forest resource inventory (FRI) was validated using field data collected in 136 stands in Nipissing Forest (Ontario, Canada). FRI-and field-based species composition matched in 54% and 56% of cases using stand count and area coverage, respectively. Possible causes of discrepancy between FRI-and field-based species composition are discussed. Low level of agreement between FRI and field data indicated a need for more extensive studies on FRI validation prior to its use for forest management planning.Key words: forest resource inventory, FRI, forest unit, photo-interpretation, timber cruise RÉSUMÉ La composition en espèces estimée à partir de l'inventaire des ressources forestières (IRF) a été validée au moyen des données de terrain recueillies dans 136 peuplements de la forêt de Nipissing (Ontario, Canada). L'IRF et la composition en espèces sur le terrain ont concordé pour 54% et 56% des cas en utilisant respectivement un décompte des peuplements et le recouvrement en superficie. Les causes probables de différence entre l'IRF et la composition en espèces sur le terrain font l'objet de discussion. Le faible taux de concordance entre l'IRF et les données du terrain indiquent la nécessité d'avoir des études plus exhaustives de la validité de l'IRF avant son utilisation à des fins d'aménagement forestier. IntroductionThe main source of information for forest management planning in Ontario is the Forest Resource Inventory (FRI). In general, a forest resource inventory may be defined as a survey of an area to provide information on the present extent, composition, structure and location of the forest (Gillis and Leckie 1993). In Ontario, the FRI is conducted on a cycle of approximately 20 years. The primary data sources for FRI production are aerial photographs taken at 1:20 000 for northern Ontario and 1:10 000 for southern Ontario. These photographs are used to delineate forest stands and assess other stand attributes through interpretation of photos calibrated with timber cruise plots established subjectively in For personal use only.

A 27-ha field study was set up in 1994 within the Petawawa Une etude sur une parcelle de 27 ha a ete entreprise en 1994 Research Forest near Chalk River, Ontario with input and supdans la Foret experimentale de Petawawa situee pres de Chak River port from local research scientists, forest managers and forest techen Ontario, avec l'aide et l'appui des chercheurs locaux, des amenicians. The study was designed to examine the effects of partial nagistes et des techniciens forestiers. L'etude a ete concue pour cutting, site preparation and underplanting in natural eastern etudier les effets des coupes partielles, de la preparation du sol white pine (Pinus strobur L.) stands. A complete randomized block et de la plantation en sous-etage dans des peuplements naturels experimental design was followed with four replicates. Three thinde pin blanc. (Pinus strobus L.) Un design de blocs experimenning (control, one-crown and two-crown spacing) and four site taux repartis totalement au hasard a ete repete quatre fois. Trois preparation (control, scarification, brush control using herbieclaircies (temoin, m e eclaircie par le haut, et deux eclaircies par tide, and both scarification and brush control using herbicide) treat1e haut) et quatre traitements de preparation du sol (temoin, were applied-Natural regeneration and planted seedling surscarifiage, controle de la competition a l'aide de phytocide, et scarvival and growth, soil nutrient availability and other environmental ifiage suivi de controle de la competition a l'aide de phytocide) factors are being monitored and ~~corded. Early results have conont ete appliques. La regeneration naturelle, la survie et la croistributed to the development of a new provincial silvicuitural sance des semis plantes, la disponibilite des elements nutritifs dans guide and a prototype expert decision support system for white personnel en place participe a la collecte des donnees sur le terrain et assure la protection contre le feu. Le site a sewi de zone Key words: eastern white pine, Pinus strobus, natural regenerde demonstration pour les personnes interessees par l'amenageation, understory planting, multidisciplinary field research, forest research sites ment des ecosystemes de pin blanc. L'etude est decrite parmi les sites du reseau FERN sur Internet.

The Great Lakes-St. Lawrence forest, particularly the eastern white (Pinus strobus L.) and red pine (P. resinosa Ait.) forests around Temagami and Sault Ste. Marie, was the centre of controversy regarding the treatment of old-growth forests in Ontario in the 1980s and 1990s. The controversy stemmed from changes in forest composition and structure occurring in the forest. For example, the Ontario public was concerned with the obvious reduction in numbers of large eastern white and red pine trees and their replacement with small, often poor quality, white birch (Betula papyrifera Marsh.), aspen (Populus tremuloides Michx.), and jack pine (Pinus banksiana Lamb.) trees. Over the past two decades, changes in legislation, forest planning and stand prescriptions have been made in Ontario and practices at the forest and stand levels have also changed significantly. The new practices are based on linking forest activities to a better understanding of ecological processes in the forest; in particular, linking harvest and regeneration activities to our current understanding of natural disturbances and plant adaptations. These practices attempt to match more closely the conditions found in forests with a heritage of natural disturbance and reproduction, i.e., old-growth forests. For example, stand-initiating disturbances result in some trees being killed, some being damaged, and some surviving. The new harvest practices consider tree adaptations and site factors when deciding whether a tree will be cut or not. This paper provides examples of how this ecosystem-based forestry is being applied in Ontario.

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