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Climate change poses risks to society through the potential to alter peak flows, low flows, and annual runoff yield. Wildfires are projected to increase due to climate change; however, little is known about their combined effects on hydrology. This study models the combined impacts of climate and landcover changes on the hydrologic regime of a snowmelt-dominated montane catchment, to identify management strategies that mitigate negative impacts. The combination of climate change and stand replacing landcover disturbance in the middle and high elevations is predicted to advance the timing of the peak flow two to nine times (depending on emission pathway) more than the advance generated by disturbance alone. The modelling predicts that the combined impacts of climate change and landcover disturbance on peak flow magnitude are generally offsetting for events with return periods less than 5–25 years, but additive for more extreme events. There is a dependency of extreme peak flows on the distribution of landcover. The modelling predicts an increasing importance of rainfall in controlling peak flow response under a changing climate, at the expense of snowmelt influence. Extreme summer low flows are predicted to become commonplace in the future, with most of the change in frequency occurring by the 2050s. Low annual yield is predicted to become more prevalent by the 2050s, but then fully recover or become less prevalent (compared to the current climate) by the 2080s, because of increased precipitation in the fall-spring period. The modelling suggests that landcover disturbance can have a mitigative influence on low water supply. The mitigative influence is predicted to be sustained under a changing climate for annual water yield, but not for summer low flow. The study results demonstrate the importance of examining complexity in three dimensions with respect to modelling changes to the hydrological regime: climate change, landcover change, and numerous hydrological indicators. Moreover, for managing watershed risk, the results indicate there is a need to carefully evaluate the interplay among environmental variables, the landscape, and the values at risk. Strategies to reduce one risk may increase others, or effective strategies may become less worthwhile in the future. [ABSTRACT FROM AUTHOR]

Forestry is an important component of Canada's economy with British Columbia (BC) contributing almost half to the national roundwood production. Yet, the country's timber supply and forest economy are threatened by climate change, with increased frequency and severity of natural disturbances and changes in forest productivity. Mountain pine beetle (Dendroctonus ponderosae) outbreaks are endemic in BC, but the latest climate change-driven outbreak has resulted in a cumulative loss of over half of all merchantable pine, leading to a mid-term timber supply shortage. In this study, we investigate the potential of commercial thinning and alternative planting regimes based on species diversification and assisted species migration to mitigate the anticipated decrease in timber supply in BC. We simulated the long-term effects of these management options in a case study area in interior BC, using a toolbox that combines management- and research-oriented data and models. We found that combining commercial thinning and species diversification has the best potential to mitigate future timber supply shortages in BC. We discuss the limits of this toolbox approach and identify research needs and recommendations for future studies aiming at modelling cumulative effects of management, climate change, and natural disturbances on timber supply. [ABSTRACT FROM AUTHOR]

Most wildfire studies are regional to global in scale; however, many of the values of interest and the weather are local phenomena that may give rise to large spatial variability in risk. We assessed the interaction of elevation and climate on fire weather for the Penticton Creek watershed in southwestern Canada for historic weather, and five climate change scenarios. Daily temperature and precipitation records spanning 100 years were generated using the LARS-WG5 weather generator and were used to calculate the fire weather indices of the Canadian Forest Fire Danger Rating System. Fire season length, restricted activity season, and fire season severity are all projected to increase by the 2050s and in some scenarios to increase further by the 2080s. Low and mid-elevations had substantially worsening risks, whereas at the highest elevations, risks were mitigated by the continuation of the snowpack. Increasing temperatures lengthened the fire season while decreasing (increasing) precipitation exacerbated (ameliorated) the intensity of the fire risk. These results indicate more variable climate change effects than in the literature. Over 24 million [km.sup.2] globally of forestland have a similar or higher degree of slope, highlighting the need for detailed topographic integration in fire studies to meet the needs of local planners. Key words: climate change, wildfire risk, fire weather risk, elevation, scale, wildfire, mountains, CFFDRS, weather generator, temperature, precipitation. La plupart des etudes sur les feux de foret sont effectuees a une echelle qui va de regionale a globale. Cependant, plusieurs des valeurs d'interet et les conditions meteorologiques sont des phenomenes locaux qui peuvent donner lieu a une grande variabilite spatiale des risques. Nous avons evalue l'interaction de l'altitude et du climat sur les conditions meteorologiques propices aux incendies forestiers dans le bassin versant de la crique Penticton dans le sud-ouest du Canada pour les conditions meteorologiques passees et cinq scenarios de changement climatique. Des donnees quotidiennes de temperature et de precipitation s'echelonnant sur 100 ans ont ete generees a l'aide du generateur de donnees meteorologiques LARS-WG5 et ces donnees ont ete utilisees pour calculer l'indice foret-meteo de la methode canadienne d'evaluation des dangers d'incendie de foret. On prevoit que la duree de la saison des feux, la saison de restriction des activites et la severite de la saison des feux augmenteront vers les annees 2050 et davantage selon certains scenarios vers les annees 2080. Les risques augmentaient substantiellement aux altitudes basses et intermediaires tandis qu'ils etaient attenuees par le maintien du couvert de neige aux altitudes plus elevees. L'augmentation des temperatures allongeait la saison des incendies tandis que la diminution des precipitations accentuait l'intensite des risques d'incendie et l'augmentation les reduisait. Ces resultats indiquent que les effets du changement climatique sont plus variables que le rapporte la litterature. Globalement, plus de 24 millions [km.sup.2] de foret ont un degre de pente semblable ou plus eleve, ce qui fait ressortir la necessite d'une integration topographique detaillee dans les etudes sur les incendies pour satisfaire les besoins des gestionnaires locaux. [Traduit par la Redaction] Mots-cles : changement climatique, risque d'incendie de foret, risques d'incendie de foret relies aux conditions meteorologiques, altitude, echelle, incendie forestier, montagnes, MCEDIF, generateur de donnees meteorologiques, temperature, precipitation., 1. Introduction Wildfire risks in many parts of the globe are of interest to forest and fire managers because of the consequences to human security and health, the economy, and [...]

Climate change poses risks to society through the potential to alter peak flows, low flows, and annual runoff yield. Wildfires are projected to increase due to climate change; however, little is known about their combined effects on hydrology. This study models the combined impacts of a climate change scenario and multiple landcover scenarios on the hydrologic regime of a snowmelt-dominated montane catchment, to identify management strategies that mitigate negative impacts from climate and/or landcover change. The combination of climate change and stand replacing landcover disturbance in the middle and high elevations is predicted to advance the timing of the peak flow three to five times more than the advance generated by disturbance alone. The modelling predicts that the combined impacts of climate change and landcover disturbance on peak flow magnitude are generally offsetting for events with return periods less than 5-25 years, but additive for more extreme events. There is a dependency of extreme peak flows on the distribution of landcover. The modelling predicts an increasing importance of rainfall in controlling peak flow response under a changing climate, at the expense of snowmelt influence. Extreme summer low flows are predicted to become commonplace in the future, with most of the change in frequency occurring by the 2050s. Low annual yield is predicted to become more prevalent by the 2050s, but then fully recover or become less prevalent (compared to the current climate) by the 2080s, because of increased precipitation in the fall-spring period. The modelling suggests that landcover disturbance can have a mitigative influence on low water supply. The mitigative influence is predicted to be sustained under a changing climate for annual water yield, but not for low flow. The study results demonstrate the importance of a holistic approach to modelling the hydrological regime rather than focusing on a particular component. Moreover, for managing watershed risk, the results indicate there is a need to carefully evaluate the interplay among environmental variables, the landscape, and the values at risk. Strategies to reduce one risk may increase others, or effective strategies may become less effective in the future. [ABSTRACT FROM AUTHOR]

In British Columbia, Canada, a recent epidemic of mountain pine beetle (Dendroctonus ponderosae Hopkins, 1902) caused widespread forest mortality. This epidemic was due in part to the changing climate, and damage from pests and diseases is expected to increase in the future. Therefore, we used a historical retrospective approach as a proxy to evaluate management options on reducing the forest health damage that may occur under a future changing climate. We assessed two landscape-scale strategies, intended to increase tree species diversity, for the response in ecosystem resilience and compared the results with the business-as-usual strategy. The assessment was based on simulation modelling of the Merritt Timber Supply Area for 1980-2060. We applied a strategy to increase the harvest of the most dominant tree species, plant more diverse species, and increase natural regeneration. This strategy resulted in greater ecological resilience (higher diversity and growing stocks), higher harvest rates, and higher, more consistent net revenue over time than the business-as-usual strategy or the strategy that only employed a diversity of planting. A sensitivity analysis indicated a high level of robustness in the results. Our study showed that it may not be necessary to compromise economic viability to reduce forest health risks and consequently improve socio-ecological resilience. Key words: resilience, adaptation, climate change, forest management, temperate forests, mountain pine beetle, landscape ecology, economic analysis, timber supply. En Colombie-Britannique, au Canada, une epidemie recente du dendroctone du pin ponderosa (Dendroctonus ponderosae Hopkins, 1902) a cause de la mortalite tres repandue dans les forets. Cette epidemie etait due en partie au changement climatique et les dommages causes par les insectes et les maladies devraient augmenter dans l'avenir. Par consequent nous avons eu recours a une retrospective historique comme substitut pour evaluer les options d'amenagement susceptibles de reduire les dommages a la foret qui pourraient survenir eventuellement a cause du changement climatique. Nous avons evalue deux strategies a l'echelle du paysage visant a augmenter la diversite des especes d'arbre pour augmenter la resilience de l'ecosysteme et nous les avons comparees a la strategie courante. devaluation a ete realisee a l'aide d'un modele de simulation de <> de 1980 a 2060. Nous avons applique une strategie consistant a accroitre la recolte des especes d'arbre les plus dominantes, a planter une plus grande diversite d'especes et a favoriser la regeneration naturelle. Avec le temps cette strategie a engendre une plus grande resilience ecologique (plus grande diversite et plus de matiere ligneuse sur pied), des taux de recolte plus eleves et un revenu net plus important et plus regulier que la strategie courante ou qu'une strategie se limitant a diversifier les plantations. Une analyse de sensibilite indiquait que les resultats avaient un haut degre de robustesse. Notre etude a montre qu'il est possible de reduire les risques pour la sante de la foret et consequemment ameliorer la resilience socio-ecologique sans necessairement compromettre la viabilite economique. [Traduit par la Redaction] Mots-cles: resilience, adaptation, changement climatique, amenagement forestier, forets temperees, dendroctone du pin ponderosa, ecologie du paysage, analyse economique, approvisionnement en bois., 1. Introduction Forest health surveys show that pests, drought, and disease are common events in forests. A changing climate is expected to contribute to increased losses of timber through a [...]

To mitigate and adapt to climate change, forest carbon sequestration and diversity of the ecosystem must be included in forest management planning, while satisfying the demand for wood products. The future provisions of ecosystem services under six realistic management scenarios were assessed to achieve that goal. These services were carbon sequestration, types and quantities of round wood harvested, and different indicators of forest health—biomass of major species, species diversity, and variation of tree age. A spatially explicit forest succession model was combined with statistical analyses to conduct the assessment at the level of both the whole forest landscape and different ecological zones (ecozones)within. An important aspect of this study was to explore the effects of the biophysical heterogeneity of different ecological zones on the outcomes of different management scenarios. The study area was located in an area of the southern Appalachian Mountains in North Carolina with high tree diversity and active forest management activities. Along with a range of management practices, such richness in diversity allowed us to examine the complexity of the interaction between management activities and species competition. The results showed that fire suppression had a greater effect on increasing biomass carbon sequestration than any management scenario that involves harvest and replanting afterward, but at the expense of other indicators of forest health. The effect of fire on species composition was the largest in the xeric parts of the study area. Based on the study results, it was proposed that a low harvest intensity with a mix of fire and fire suppression across the landscape would best balance the need for round wood products, biomass car-bon sequestration, and desirable species composition. This study also demonstrated that the combination of a spatially explicit forest succession model and statistical analyses could be used to provide a robust and quantifiable projection of ecosystem service provisions and possible trade-offs under different management scenarios. [ABSTRACT FROM AUTHOR]

The article offers suggestions on how to manage the forests in British Columbia for carbon storage. It advises to cut degradation and deforestation to realize an immediate benefit to the atmosphere through the reduction in greenhouse gas (GHG) emissions. Maintaining overall carbon stocks can be achieved by conserving areas that are expected to be stable for carbon storage and uptake. Carbon stored in the soil can be maintained by reducing soil disturbance.