Recent publications

Seed-source effects, assisted migration, and fitness / Effets de l'origine des graines, migration assistée et valeur adaptive

Wed, 16 May 2012

Scientists at the Canadian Forest Service - Atlantic Forestry Centre (CFS-AFC) have compared whtie pine (Pinus strobus (L.)) productivity from large, central Ontario (ON) and small, isolated Newfoundland (NL) populations from different latitudes. The declining population numbers and sizes of NL white pine have become an important conservation issue because they pose a threat to its survival as a naturally occurring species on the island (Newfoundland Forest Service 1997). A common garden experiment was used to quantify and compare adaptive traits of white pine from the two regions. The information gathered begins to address an issue of pressing concern to forest professionals: what are suitable seed-source (provenance) deployment strategies in light of climate change predictions?

Silvicultural control of the white pine weevil / Lutte sylvicole contre le charançon du pin blanc

Wed, 16 May 2012

Canadian Forest Service scientists at the Atlantic Forestry Centre (AFC) have quantified white pine (Pinus strobus) productivity and weevil damage under three silvicultural treatments (STs). Forest professionals are interested in managing for increased white pine productivity and regeneration, but concern about weevil damage and blister rust has reduced regeneration efforts. This is one of the first experiments to thoroughly quantify and compare the trade-off between weevil protection and growth using different levels of shade provided by an overhead or canopy nurse crop.

One hundred years of BCFS-CFS collaboration

Fri, 11 May 2012

The British Columbia Forest Service (BCFS) and the Canadian Forest Service (CFS) have a long history of collaboration across a wide range of functions and topics. This includes research, technology transfer and extension, co-management and delivery of federal–provincial agreements, and partnering on national and international initiatives. As the BCFS approaches its centennial, it is interesting to examine the achievements that have come from this 100-year relationship. The nature of the various projects and initiatives undertaken over the years reflects the evolving nature of forest management, and the relative strengths of the CFS and BCFS have contributed to successful outcomes in many collaborative initiatives. Looking forward, we believe a continuation of CFS–BCFS partnering will benefit both institutions, and will help ensure management of BC’s forests continues to balance the multiple needs of current and future generations.

Incorporating field wind data into FIRETEC simulations of the International Crown Fire Modeling Experiment (ICFME): preliminary lessons learned.

Fri, 11 May 2012

Field experiments are one way to develop or validate wildland fire-behavior models. It is important to consider the implications of assumptions relating to the locality of measurements with respect to the fire, the temporal frequency of the measured data, and the changes to local winds that might be caused by the experimental configuration. Twenty FIRETEC simulations of International Crown Fire Modeling Experiment (ICFME) plot 1 and plot 6 fires were performed using horizontally homogenized fuels. These simulations enable exploration of the sensitivity of model results to specific aspects of the interpretation and use of the locally measured wind data from this experiment. By shifting ignition times with respect to dynamic measured tower wind data by up to 2 min, FIRETEC simulations are used to examine possible ramifications of treating the measured tower winds as if they were precisely the same as those present at the location of the fire, as well as possible implications of temporal averaging of winds or undersampling. Model results suggest that careful consideration should be paid to the relative time scales of the wind fluctuations, duration of the fires, and data collection rates when using experimentally derived winds as inputs for fire models.

Prevalence, transmission and mortality associated with Nosema fumiferanae infections in field populations of spruce budworm Choristoneura fumiferana

Fri, 11 May 2012

1 The prevalence, intensity and transmission of Nosema fumiferanae (Thomson) Microsporidae) infections and potential impacts on the survival of field populations of spruce budworm Choristoneura fumiferana (Clem.) were examined in three plots in New Brunswick, Canada, from 1983 to 1992. 2 The highest prevalence of N. fumiferanae infection in post-hibernation second-instar larvae occurred in the plot where prevalence in female pupae was the highest in the previous generation, suggesting higher rates of vertical transmission. There was little change in the prevalence of N. fumiferanae infections between the second and sixth instars in the later generations. In the two other plots, N. fumiferanae prevalence increased by approximately 25% from the second to sixth larval stadia. Coincident with the changes in N. fumiferanae prevalence were substantial declines in the populations of spruce budworms, making it difficult to determine rates of horizontal transfer of the disease. 3 In all plots and in all years, there were progressive increases in the intensity of N. fumiferanae infections (spore loads/individual) from the second to sixth instars and pupae. 4 Annual spruce budworm mortality associated with N. fumiferanae was ≤15% of all mortality in reared specimens and was positively correlated with but generally less than 30% of annual N. fumiferanae prevalence.

A first step towards identification of tannin-derived black carbon: Conventional pyrolysis (Py–GC–MS) and thermally assisted hydrolysis and methylation (THM–GC–MS) of charred condensed tannins

Thu, 10 May 2012

Tannins account for a significant proportion of plant biomass and are likely to contribute to the residues formed by incomplete biomass combustion (black carbon, BC). Nonetheless, the molecular properties of thermally modified tannins have not been investigated in laboratory charring experiments. We applied conventional analytical pyrolysis–gas chromatography–mass spectrometry (Py–GC–MS) and thermally assisted hydrolysis and methylation (THM–GC–MS) to investigate the effects of heat treatment with a muffle furnace on the properties of condensed tannins (CT) from Corsican pine (Pinus nigra) needles. Py–GC–MS showed a decrease in the relative abundance of the 1,2,3-trihydroxybenzenes (pyrogallols) at ⩾300 °C and of the dihydroxybenzenes (mainly catechols) at ⩾350 °C due to dehydroxylation of the CT B ring. Further dehydroxylation led to formation of monohydroxybenzenes (phenols), which showed a strong enrichment between 350 and 400 °C and, at higher temperatures, to a series of monocyclic and polycyclic aromatics [benzene, alkyl benzenes and polycondensed aromatic hydrocarbons (PAHs)]. Degradation of the A ring could not be recognized via Py–GC–MS, probably because of the poor chromatographic behavior of 1,3,5-trihydroxybenzenes (phloroglucinols). The progressive dehydroxylation and eventual polycondensation of the CT B ring was corroborated using THM–GC–MS. In addition, with THM–GC–MS the thermal rearrangement of CT A rings at 300 °C and higher was inferred from the relative abundance of 1,3,5-trimethoxybenzenes (methylated phloroglucinol derivatives). These compounds were observed at moderate/high temperature (up to 450 °C) and can not be produced from THM of lignin, suggesting that they may be markers of CT in natural BC samples.

Natural enemies associated with Sirex noctilio (Hymenoptera: Siricidae) and S. nigricornis in Ontario, Canada. 2012. Ryan, K.; De Groot, P.; Nott, R.W.; Drabble, S. Ochoa, I.; Davis, C.; Smith, S.M.; Turgeon, J.J. Environmental Entomology 41(2):289-297.

Thu, 10 May 2012

Sirex noctilio F. is an exotic woodwasp now found in eastern North America where it shares natural enemies with native woodwasps of Pinus spp. To study the extent to which native hymenopteran parasitoids and parasitic nematodes could affect woodwasp populations, 60 Pinus trees with symptoms of S. noctilio attack were felled in 2007 and 2008 in Ontario, Canada. Each tree bole was cut into 1-m sections that were placed in individual rearing tubes; emergence was monitored from May to November of the year of felling. Female S. noctilio were dissected to assess parasitism by the nematode Deladenus siricidicola Bedding. Two species of Siricidae emerged from these trees; S. noctilio, which accounted for most of the specimens collected, and S. nigricornis F. Of the three species of parasitoid that emerged, Ibalia leucospoides (Hochenwarth) was the most abundant, accounting for an overall hypothetical Siricidae parasitism rate of almost 20%. This parasitoid emerged over a similar time period as S. noctilioÑbetween early July and early September. Except in trees 15 m in height, parasitism by I. leucospoides generally appeared uniform throughout the bole. Parasitism rates did not vary between the 2 yr, but did between sites in 1 yr. Parasitic nematodes were found in the haemocoel of about one third of S. noctilio females dissected but were never found sterilizing the eggs; none were found in S. noctilio emerging from P. resinosa. These findings suggest that I. leucospoides is currently the primary invertebrate natural enemy of S. noctilio in Ontario.

Digital high spatial resolution aerial imagery to support forest health monitoring: the mountain pine beetle context

Thu, 10 May 2012

We summarize the capacity of high spatial resolution (<1 m) digital aerial imagery to support forest health monitoring. We review the current use of digital aerial imagery in the context of the recent mountain pine beetle epidemic in western Canada. Supported by this review, we posit that high spatial resolution digital aerial imagery can play at least two critical roles in forest health monitoring. First, the capacity to characterize damage at the individual tree level directly supports a broad range of forest health information needs (e.g., tree-level attributes for estimating the population at risk and for inputs to models, estimates of mortality, rates of population growth). Second, the level of detail afforded by the digital high spatial resolution aerial imagery provides critical calibration and validation data for lower spatial resolution remotely sensed imagery (e.g., QuickBird, Landsat) for large-area detection and mapping of forest damage and can be used in a double sampling scheme as a bridge between detailed field measures and landscape-level estimates of mortality. In an era with increasing numbers of commercially deployed sensors capable of acquiring high spatial resolution satellite imagery, the flexibility and cost-effectiveness of aerial image options should not be disregarded. Moreover, experiences with airborne imagery can continue to inform applications using high spatial resolution satellite imagery for forest health information needs.

Impact of disturbance characteristics and age on grizzly bear habitat selection

Tue, 08 May 2012

Grizzly bears (Ursus arctos) have complex reactions to forest disturbances due to their use of forest clearings for foraging, their large home ranges, and the continued human expansion into undisturbed grizzly bear habitat. The goal of this paper is to quantify how grizzly bears interact with forest disturbances over time in west-central Alberta in order to inform habitat management decisions. This is accomplished using a four-decade remotely sensed disturbance history and detailed grizzly bear movement and habitat use information. Global positioning systems (GPS) collars were used to collect telemetry data for 22 adult grizzly bears (8 females, 14 males) from 2005 to 2009 in the eastern slopes of the Canadian Rockies. The resultant telemetry data were partitioned based on known biological variation in habitat selection into sex and seasonal groups. Density of grizzly bear telemetry locations was calculated for each forest disturbance and compared to expected density via a randomization conditioned on observed trends in overall habitat use. The comparison of observed and expected density of grizzly bear telemetry locations allowed disturbances to be labelled as selected or avoided. Each disturbance was attributed with characteristics (area, elevation, average tasselled cap transformation (TCT) greenness, and distance to nearest populated place), which were compared between selected and avoided disturbances using a Mann–Whitney U-test. Male bears selected for 30–40-year-old disturbances more frequently than younger disturbances; females demonstrated equal selection of all ages of disturbances except those less than 10 years old. Females selected for disturbances more in the summer and fall than the spring. Disturbances selected by female bears were larger, with lower TCT greenness, and a consistent elevation (1250–1300 m) across seasons and disturbance age. Male bears showed lower selection of disturbances in the fall than in other seasons, and lower selection than females in the summer and fall. Compared to females, disturbances selected by males were larger, and more likely to show seasonal variation in greenness and elevation. Both sexes selected for larger disturbances of all ages, although disturbance size has generally decreased through time. Limiting human access to disturbances with characteristics attractive to grizzly bears will reduce grizzly bear and human interactions, and reduce mortality.

New Staphylinidae (Coleoptera) records with new collection data from New Brunswick, and an addition to the fauna of Quebec, Canada: Aleocharinae.

Tue, 08 May 2012

Thirty-eight species of Aleocharinae are newly reported from New Brunswick, bringing the total number of species known from the province to 216. Thirty-one of these species are newly recorded for the Maritime provinces, and four of them, Phloeopora oregona Casey, Gyrophaena michigana Seevers, Gyrophaena wisconsinica Seevers, and Tomoglossa decora (Casey), are newly recorded for Canada. Tomoglossa constitutes a new generic record for Canada. Collection and habitat data for all these species are presented and discussed. Color habitus, median lobe of the aedeagus, and male tergite and sternite 8 images are presented for the first time for P. oregona, and references to illustrations are provided for all other species included in this paper. A color habitus image is presented for T. decora.