D. L. Spittlehouse

• Ministry of Forests

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 evalu...

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 snow...

Globally, forests are facing a wide range of disturbances that significantly impact carbon dioxide (CO 2) and water vapour exchange. In British Columbia (BC), Canada, coastal Douglas-fir and interior lodgepole pine are two of the most common tree species. Led by some early studies in the 1970s, two long-term BC forest research clusters were establi...

We examined the seasonality of photosynthesis in 46 evergreen needleleaf (evergreen needleleaf forests (ENF)) and deciduous broadleaf (deciduous broadleaf forests (DBF)) forests across North America and Eurasia. We quantified the onset and end (StartGPP and EndGPP) of photosynthesis in spring and autumn based on the response of net ecosystem exchan...

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 th...

Interception of rainfall by forest canopies and its evaporation back to the atmosphere is an important component of the hydrological balance. We quantify the influence of six mature forests at two coastal and one southern interior locations in British Columbia on interception loss. Drainage from the canopy was measured with throughfall troughs and...

Key messages Indigenous Peoples in B.C. are experiencing and adapting to climate change (see section 5.2) Indigenous Peoples are uniquely impacted by climate change, and are also uniquely resilient as a result of Indigenous Knowledge Systems. Successful adaptation is more likely when co-created with Indigenous Peoples in ways that protect and st...

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 clima...

The Upper Penticton Creek Watershed Experiment is one of a handful of forestry-focused paired-catchment experiments in the snow-dominated zone of western North America. The study involves an undisturbed control catchment and two treatment catchments. Streamflow has been monitored at weirs on all three streams since 1985. Following a pre-harvest mon...

Over the past 35 years, the Upper Penticton Creek (UPC) Watershed Experiment has supported forest hydrology research in south-central British Columbia (BC), Canada. This paper provides a synthesis of research results, highlights the challenges facing UPC and identifies new research directions. Clearcutting approximately 50% of two small, snow-domin...

• Regional climate trends in the NWB region during the latter 20th and early 21st century indicate an increase in temperature of approximately 2°C (3.6°F). Precipitation has increased, but the trends are small compared to observed interannual variability. • Regionwide, climate model projections indicate an increase in mean annual temperature of 2.1...

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This study analysed trends from 1965-2015 for various surface and climate variables for the Cowichan basin. There were statistically significant trends in rising annual, January, June and July air temperatures. Trends in groundwater detail particular wells are in a state of decline, as are surface waters, particularly with decreases for July, Augus...

The most recent mountain pine beetle (MPB) (Dendroctonus ponderosae) outbreak in British Columbia (BC), which began in the late 1990s, killed ∼54% of the mature merchantable lodgepole pine and was expected to impact gross primary productivity (GPP), ecosystem respiration (R) and thus net ecosystem productivity (NEP) of infested stands. Eddy-covaria...

With population growth, climate change, and increasing forest disturbance, understanding the complex relationships between forests and water is key to sustaining future forest resources, aquatic habitat, and water supplies. Research into forest and water interactions continues to expand our understanding of ecohydrological processes and our ability...

Daily air temperature and total precipitation data have been collected in the Cowichan River valley for more than 100 years as part of Environment and Climate Change Canada’s monitoring network. However, none of the weather stations have operated continuously for the whole period. This report describes combining station records to create a continuo...

Tree mortality due to the recent mountain pine beetle (MPB) (Dendroctonus ponderosae) outbreak in British Columbia (BC) is expected to impact evapotranspiration (E), gross primary productivity (GPP), and snow accumulation and melt, thereby influencing ecosystem hydrology. To quantify the impact on E and GPP, we have made eddy-covariance (EC) measur...

Tree mortality due to the recent mountain pine beetle (MPB) (Dendroctonus ponderosae) outbreak in British Columbia (BC) is expected to impact evapotranspiration (E), gross primary productivity (GPP), and snow accumulation and melt, thereby influencing ecosystem hydrology. To quantify the impact on E and GPP, we have made eddy-covariance (EC) measur...

The Upper Penticton Creek watershed experiment has collected 28 years of streamflow data from 2 small snow‐dominated watersheds on the Okanagan Plateau of British Columbia, where the effects of timber harvesting on streamflow regime are of broad concern. We apply 3 empirical analysis techniques to these data to evaluate changes in streamflow regime...

Given the widespread ecological implications that would accompany any significant change in evaporative demand of the atmosphere, this study investigated spatial and temporal variation in several accepted expressions of potential evaporation (PE). The study focussed on forest regions of North America, with 1 km-resolution spatial coverage and a mon...

Given the widespread ecological implications that would accompany any significant change in evaporative demand of the atmosphere, this study investigated spatial and temporal variation in several accepted expressions of potential evaporation (PE). The study focussed on forest regions of North America, with 1 km-resolution spatial coverage and a mon...

Large volumes of gridded climate data have become available in recent years including interpolated historical data from weather stations and future predictions from general circulation models. These datasets, however, are at various spatial resolutions that need to be converted to scales meaningful for applications such as climate change risk and i...

Parameters and the results of the model fit for the piecewise function for monthly Degree-days above 5°C (DD > 5). (PDF)

Parameters and the results of the model fit for the piecewise function for monthly Degree-days below 18°C (DD < 18). (PDF)

Parameters and the results of the model fit for monthly Number of frost-free days (NFFD). (PDF)

Parameters and the results of the model fit for monthly precipitation as snow (PAS). (PDF)

Equations of derived climate variables. (PDF)

Parameters and the results of the model fit for monthly Degree-days below 0°C (DD < 0). (PDF)

Parameters and the results of the model fit for the piecewise function for monthly Degree-days above 18°C (DD > 18). (PDF)

Increasing the resilience of ecological and sociological systems has been proposed as an option to adapt to changing future climatic conditions. However, few studies test the applicability of those strategies to forest management. This paper uses a real forest health incident to assess the ability of forest management strategies to affect ecologica...

Long-term studies at Mayson Lake (ML) and Upper Penticton Creek (UPC) in British Columbia's southern interior quantify snow-dominated hydrologic response to natural disturbances and logging. Following natural disturbance at ML, changes in snow accumulation related directly to mountain pine beetle attack were measurable by the fifth year following a...

Background / Purpose: We have limited understanding of how the growth of individual, co-occurring tree species will be altered by climate change, but making such projections is important both for managing forest resources and for advancing knowledge of forest behavior under global change. Here we apply an ecophysiological forest production model...

Temperature (T), precipitation (P), potential evapotranspiration (PET, estimated using the Hamon method) and discharge (Q) from catchment 5-water-year cool periods (period with lowest average temperature) and 5-water-year warm periods (period with highest average temperature).

Over the past decade, British Columbia (BC), has experienced the largest mountain pine beetle (MPB) outbreak on record. This study used the eddy-covariance (EC) technique to examine the impact of the MPB attack on evapotranspiration (E) and associated canopy characteristics of two lodgepole pine stands with secondary structure (trees, saplings and...

Climate warming is projected to affect forest water yields but the effects are expected to vary. We asked how forest type and age affect water yield resilience to climate warming. To answer this question, we examined the variability in historical water yields at long-term experimental catchments across Canada and the United States over 5-year cool...

This study quantified changes in snow accumulation and ablation with forest defoliation in a young pine stand attacked by mountain pine beetle, a mature mixed species stand, and a clearcut in south-central British Columbia. From 2006 to 2012, as trees in the pine stand turned from green to grey, average canopy transmittance increased from 27% to 49...

We present a comprehensive set of interpolated climate data for western North America, including monthly data for the last century (1901-2009), future projections from atmosphere-ocean general circulation models (A2, A1B, and B1 scenarios of the WCRP CMIP3 multimodel dataset), as well as decadal averages and multiple climate normals for the last ce...

The recent mountain pine beetle (MPB) outbreak has had an impact on the carbon (C) cycling of lodgepole pine forests in British Columbia. This study examines how partial harvesting as a forest management response to MPB infestation affects the net ecosystem production (NEP) of a mixed conifer forest (MPB-09) in Interior BC. MPB-09 is a 70-year-old...

increase at a faster rate in the future, accompanied by changes in precipitation patterns and increases in the occurrence of extreme weather events. In western North America, projected increases in mean annual temperatures range from �1 to 3.5° C by the 2050s, and although projected changes in precipitation patterns are more complex to model, more...

The recent mountain pine beetle (MPB) outbreak has had an impact on the carbon (C) cycling of lodgepole pine forests in British Columbia. This study examines how partial harvesting as a forest management response to MPB infestation affects the net ecosystem production (NEP) of a mixed conifer forest (MPB-09) in Interior BC. MPB-09 is a 70-yr old st...

Wood nitrogen isotope composition (δ15N) provides a potential retrospective evaluation of ecosystem N status but refinement of this index is needed. We calibrated current wood δ15N of Douglas-fir (Pseudotsuga menziesii), an ectomycorrhizal tree species, against a productivity gradient of contrasting coastal forests of southern Vancouver Island (Can...

Over the past decade, the mountain pine beetle (MPB) (Dendroctonus ponderosae) has killed 17.5 million ha of forest in British Columbia. The forest sector responded by increasing the annual allowable cut to salvage the beetle-killed lodgepole pine trees (Pinus contorta var. latifolia). The most common strategy is to clearcut the entire stand. This...

Abstract Disturbances play an important role in determining the C balance of North American forests. This study used the eddy covariance (EC) technique to examine the impact of mountain pine beetle (MPB) (Dendroctonus ponderosae) outbreak on the gross ecosystem photosynthesis (Pg), ecosystem respiration (Re) and net ecosystem production (NEP), of...

The effects of climatic factors and vegetation type on evapotranspiration (E) and water use efficiency (WUE) were analyzed using tower-based eddy-covariance (EC) data for nine mature forest sites, two peatland sites and one grassland site across an east-west continental-scale transect in Canada during the period 2003-2006. The seasonal pattern of E...

This study addresses the need to provide comprehensive historical climate data and climate change projections at a scale suitable for, and readily accessible to, researchers and resource managers. This database for western North America (WNA) includes over 20 000 surfaces of monthly, seasonal, and annual climate variables from 1901 to 2009; several...

The mountain pine beetle (MPB) outbreak has had a major impact on the carbon (C) and water balances of forests in Interior BC, Canada. As a management response, the forest sector has increased the annual allowable cut to enable partial harvesting in the timber supply areas. Protecting the non-pine secondary structure provides opportunities for mid-...

Natural forest disturbances (e.g., mountain pine beetle (MPB), wildfire) significantly affect snow processes in snowmelt dominated watersheds. Stand-scale studies indicate that post-disturbance forest canopy increases the amount and date of maximum SWE, permits greater transmission of incident radiation at the snow surface, and thus, increases rate...

Hydrologic models have increasingly been used in forest hydrology to overcome the limitations of paired watershed experiments, where vegetative recovery and natural variability obscure the inferences and conclusions that can be drawn from such studies. Models are also plagued by uncertainty, however, and parameter equifinality is a common concern....

Over the coming decades, climate change will increasingly affect forest ecosystem processes, but the future magnitude and direction of these responses is uncertain. We designed 12 scenarios combining possible changes in tree growth rates, decay rates, and area burned by wildfire with forecasts of future harvest to quantify the uncertainty of future...

Coefficients for the calculation of soil water balance components at seven sites on a forested slope were determined using only measurements of daily solar irradiance, maximum and minimum air temperature and rainfall, and weekly root zone soil water content during a 2-year period. Site parameters required were root zone depth, soil water retention...

The relationships between annual tree-ring growth and growing season climate were explored, studying 70-year-old coastal Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees in three sites of different moisture microclimates within productive forest lands. Climate data were augmented via a water balance model to calculate soil moisture deficits....

As a synthesis document, the Compendium consolidates our current scientific knowledge and operational experience into 19 chapters organized around six themes: the regional context, watershed hydrology, watershed geomorphology, water quality, stream and riparian ecology, and watershed management decision support. These chapters summarize the basic s...

British Columbia (BC), Canada is experiencing a severe mountain pine beetle (MPB) (Dendroctonus ponderosae) epidemic extending over an area of 135,000 km2. The widespread mortality of lodgepole pine (Pinus contorta var. latifolia) caused by the beetle has significant implications for BC's timber supply and Canada's carbon (C) budget. This study use...

This study investigated the 2-year response to nitrogen (N) fertilization of three different-aged Douglas-fir stands on the west coast of Canada on eddy covariance (EC)-measured net ecosystem productivity (NEP), gross primary productivity (GPP), ecosystem respiration (R) and evapotranspiration (E). Fertilizer application took place in January 2007,...

This chapter introduces British Columbia’s weather and climate. “Weather” refers to the specific condition of the atmosphere at a particular place and time. It is measured in terms of variables including wind speed and direction, air temperature, humidity, atmospheric pressure, cloudiness, and precipitation. Weather can change from hour to hour, da...

We used the eddy-covariance technique to measure evapotranspiration (E) and gross primary production (GPP) in a chronosequence of three coastal Douglas-fir (Pseudotsuga menziesii) stands (7, 19 and 58 years old in 2007, hereafter referred to as HDF00, HDF88 and DF49, respectively) since 1998. Here, we focus on the controls on canopy conductance (gc...

Plant growth and potential photosynthetic carbon uptake are strongly controlled by water availability and climatic conditions. The study of evapotranspiration (E) among a variety of terrestrial ecosystems is therefore fundamental to understand its role within the water cycle and linkage to carbon fluxes. In this study, we analyze tower-based eddy-c...

Using the eddy-covariance technique, we have been measuring, since 1998, CO2, water vapour and energy exchange between the atmosphere and the ecosystem in three different-aged Westcoast Douglas-fir (Pseudotsuga menziesii) stands (9, 21 and 60 year-old in 2009, hereafter known as HDF00, HDF88 and DF49, respectively). These stands were fertilized wit...

Changes to British Columbia’s lodgepole pine forests due to the mountain pine beetle (mpb) outbreak will affect stand water balances, hillslope hydrology, and streamflow in many watersheds. The magnitude of this disturbance has prompted a range of research at both stand and watershed scales to address uncertainty about the hydrologic effects of mpb...

Fertilization is one of the eligible management practices for C sequestering and hence reducing CO2 emissions under Article 3.4 of the Kyoto Protocol. In the coastal regions of British Columbia, which have very little nitrogen (N) deposition from pollution sources owing to their remote location, and soils deficient in N (Hanley et al., 1996), Dougl...

This study investigated how nitrogen (N) fertilization with 200 kg N ha−1 of a 58-year-old West Coast Douglas fir stand influenced its net greenhouse gas (GHG) global warming potential (GWP) in the first year after fertilization. Effects of fertilization on GHG GWP were calculated considering changes in soil N2O emissions, measured using the static...

As the mountain pine beetle (MPB) infestation expands into the southern interior, changes to British Columbia's lodgepole pine forests will affect stand water balances, hillslope hydrology and streamflow in many watersheds. The large spatial extent of this disturbance has prompted research from the stand-to watershed-scales to address uncertainty a...

Understanding the complex interactions between forests, forest land-use, natural disturbances, streamflow, and groundwater is essential to sustainable water resource management. Throughout the dry southern interior of British Columbia (BC), both the security of water supplies and the protection of aquatic habitat are issues of ongoing concern, part...

We determined the stable carbon isotope composition (δ1.3C) of cellulose extracted from early and late wood in Douglas fir [Pseudotsuga menziexii (Mirb.) Franco] tree rings. Data were obtained for the period 1962 to 1981, at the start of which the trees were 20 years old. A water balance model was used to calculate daily stand transpiration and wat...

Applying climate data in resource management requires matching the spatial scale of the climate and resource databases. Interpolating climate data in mountainous regions is difficult. In this study, we present methodology to generate scale-free climate data through the combination of interpolation techniques and elevation adjustments. We apply it t...

C limateBC is a computer program that offers high-resolution, spatial climate data for current and future climate change scenarios (Wang et al. 2006). The program was developed because applying climate data in resource management often requires matching spatial scales of climate and resource databases. ClimateBC provides data for BC and the Alaska...

Current changes in climate are already affecting forest species. Future climate change will bring greater changes in range of occurrence, forest disturbance and growth rates. These changes in turn will affect society's ability to use forest resources. We already take account of climate in forest management; in the future we will have to apply these...

Future climate change will affect society's ability to use forest resources. We take account of climate in forest management and this will help us adapt to the effects of climate change on forests. However, society will have to adjust to how forests adapt by changing expectations for the use of forest resources because management can only influence...

Forest harvesting can increase solar radiation in the riparian zone as well as wind speed and exposure to air advected from clearings, typically causing increases in summertime air, soil, and stream temperatures and decreases in relative humidity. Stream temperature increases following forest harvesting are primarily controlled by changes in insola...

Quantification of the relationships between snow and forest cover, including its removal through logging, insects or disease and its regrowth, is a prerequisite to assessing the effects of forestry practices on streamflow from montane and boreal forest watersheds. Over a 3 year period, a juvenile and a juvenile-thinned lodgepole pine (Pinus contort...

The annual net ecosystem productivity (FNEP) of a second-growth Douglas-fir stand established in 1949 on the Canadian West Coast varied considerably over the 4-year period between 1998 and 2001. This period included the El Niño/La Niña cycle during the northern hemispheric winters of 1997/1998 and 1998/1999, offering a unique opportunity to study h...

This study evaluates the performance and internal structure of the distributed hydrology soil vegetation model (DHSVM) using 1998–2001 data collected at Upper Penticton Creek, British Columbia, Canada. It is shown that clear-cut snowmelt rates calculated using data-derived snow albedo curves are in agreement with observed lysimeter outflow. Measure...

Methods for obtaining daily snowmelt rates in forest and clearcut environments were evaluated at high elevation sites in the southern interior of British Columbia, Canada (Upper Penticton Creek Watershed Experiment). Snowmelt was measured during spring 1998 to 2002 in a clearcut with snowmelt lysimeters and calculated for the clearcut and a forest...

The process to use the current flux measurement to assess the long-term forest carbon balance was described. The carbon dioxide flux measurements have been made during a period with less water restrictions to trasnspiration. Eddy correlation measurements of evaporation and carbon dioxide flux have been made above the canopy from july 1997 to the pr...

Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) is an important species for timber production in the Georgia Basin with growth dependent on moisture availability during the summer. The potential effect of climate change on water availability and the productivity of coastal Douglas-fir was evaluated using relationships between available water and...

Two years of continuous eddy covariance measurements were used to characterize the seasonal and annual variability of the latent and sensible heat fluxes above a 50-year-old, 33 m tall coastal Douglas-fir forest on the east coast of Vancouver Island, Canada. The total annual evaporation was found to be very conservative for this temperate coniferou...

Adaptation in forestry is sustainable forest management that includes a climate change focus. Climate change over the next 100 years is expected to have significant impacts on forest ecosystems. The forestry community needs to evaluate the long-term effects of climate change on forests and determine what the community might do now and in the future...

Forest soils often contain many large coarse fragments making it difficult to insert probes to measure soil water content. The ability of time domain reflectometry (TDR) to give reliable measurements of water content in soil with up to 40% coarse fragments was evaluated at a site in the southern interior of British Columbia, Canada. A commercial ti...

Fundamental plant-environment relationships were revealed by analyses of 20-yr height and survival of 118 populations representing two subspecies of Pinus contorta growing in common gardens at 60 environmentally disparate test sites in British Columbia. The approach involved (1) preparing models that described the general climate of British Columbi...