Reification and Truthmaking Patterns

Reification is a standard technique in conceptual modeling, which consists of including in the domain of discourse entities that may otherwise be hidden or implicit. However, deciding what should be rei- fied is not always easy. Recent work on formal ontology offers us a simple answer: put in the domain of discourse those entities that are responsible for the (alleged) truth of our propositions. These are called truthmakers. Re-visiting previous work, we propose in this paper a systematic analysis of truthmaking patterns for properties and relations based on the ontolog- ical nature of their truthmakers. Truthmaking patterns will be presented as generalization of reification patterns, accounting for the fact that, in some cases, we do not reify a property or a relationship directly, but we rather reify its truthmakers

Western Spruce Budworm and Wildfire: Is There a Connection?

In the interior Pacific Northwest, extensive defoliation of mixed conifer forests during outbreaks of western spruce budworm (WSB) may leave the visual impression of a tinderbox with trees primed to burst into flame. But is this the case? We addressed this question with funding from the USDA/U.S. Department of the Interior Joint Fire Science Program (project 09– 1–06–5). Here we summarize our three recent publications exploring the potential relationship between WSB outbreaks and fire. We used a multimethod approach to explore potential disturbance interactions that might cause one disturbance to change the occurrence or severity of the other. We used tree-ring records to see whether WSB and fire are related in time and computer modeling to see how defoliation could affect crown fire behavior

Pennsylvania Folklife Vol. 25, No. 3

• The Pennsylvania Germans and the American Revolution • The Blooming Grove Colony • The Salebill • The Schlegel Family and the Rosicrucian Movement • A Log Settler\u27s Fort/Home • Pennsylvania Dutch Studies at Ursinus College, 1976 • The Country Sale: Folk-Cultural Questionnaire No. 43https://digitalcommons.ursinus.edu/pafolklifemag/1067/thumbnail.jp

Exploring the role of fire, succession, climate, and weather on landscape dynamics using comparative modelling

An assessment of the relative importance of vegetation change and disturbance as agents of landscape change under current and future climates would (1) provide insight into the controls of landscape dynamics, (2) help inform the design and development o

Western Spruce Budworm Outbreaks Did Not Increase Fire Risk over the Last Three Centuries: A Dendrochronological Analysis of Inter-Disturbance Synergism

Insect outbreaks are often assumed to increase the severity or probability of fire occurrence through increased fuel availability, while fires may in turn alter susceptibility of forests to subsequent insect outbreaks through changes in the spatial distribution of suitable host trees. However, little is actually known about the potential synergisms between these natural disturbances. Assessing interdisturbance synergism is challenging due to the short length of historical records and the confounding influences of land use and climate changes on natural disturbance dynamics. We used dendrochronological methods to reconstruct defoliator outbreaks and fire occurrence at ten sites along a longitudinal transect running from central Oregon to western Montana. We assessed synergism between disturbance types, analyzed long-term changes in disturbance dynamics, and compared these disturbance histories with dendroclimatological moisture availability records to quantify the influence of moisture availability on disturbances. After approximately 1890, fires were largely absent and defoliator outbreaks became longer-lasting, more frequent, and more synchronous at our sites. Fires were more likely to occur during warm-dry years, while outbreaks were most likely to begin near the end of warm-dry periods. Our results show no discernible impact of defoliation events on subsequent fire risk. Any effect from the addition of fuels during defoliation events appears to be too small to detect given the overriding influence of climatic variability. We therefore propose that if there is any relationship between the two disturbances, it is a subtle synergistic relationship wherein climate determines the probability of occurrence of each disturbance type, and each disturbance type damps the severity, but does not alter the probability of occurrence, of the other disturbance type over long time scales. Although both disturbance types may increase in frequency or extent in response to future warming, our records show no precedent that western spruce budworm outbreaks will increase future fire risk

Interactions of Insects, Fire and Climate on Fuel Loads and Fire Behavior in Mixed Conifer Forest

Mixed-conifer forests in the interior Pacific Northwest are subject to sporadic outbreaks of the western spruce budworm, the most destructive defoliator in western North America. Such outbreaks usually occur synchronously over broad regions and lead to widespread decreases in growth rates and low to moderate levels of mortality. In the last century, changing land use and fire suppression have led to an increase in the amount and density of host tree species, and changed fire regimes. This has altered the severity and frequency of both fire and western spruce budworm. In spite of the ecological and economic significance of these disturbances, their interactions with each other and with climate are not fully understood. We used two approaches to examine these interactions across a range of temporal and spatial scales. First, we used dendrochronological methods to examine the climatic drivers of budworm outbreaks and fires and to assess the association of fire and budworm over three centuries in 13 stands across Oregon, Idaho, and Montana. Second, we used a mechanistic fire behavior model, the Wildland-urban interface Fire Dynamics Simulator (WFDS) to examine the sensitivity of crown fire to multiple aspects of defoliated crown fuels, including changing crown bulk density and branchwood moisture. The dendrochronological reconstructions revealed repeated western spruce budworm outbreaks and fires over the past several centuries, with different climate events associated with each disturbance. Outbreaks sometimes persisted more than a decade and were often synchronous among sites. An average of 12 outbreaks occurred at each site, each lasting an average of 12 years in length, with an average of 15 years between outbreaks. Outbreak initiation was often regionally synchronous. Synchrony was higher in the second half of the record (since 1900), possibly due to increased abundance and continuity of host trees during the fire suppression era. Outbreak duration and frequency were also somewhat higher after approximately 1890. We found that warm-dry conditions occurred one to three years preceding outbreak initiation, suggesting that drought-stressed trees permit population growth to a level at which predators no longer strongly limit the budworm population. The mean fire return interval in these mixed-conifer stands was 34 years (range: 16 – 53 years). Fires tended to occur during warm-dry years. We found no evidence of a consistent relationship between the timing of fires and western spruce budworm outbreaks. Western spruce budworm is associated with the ends of droughts and fire is simply associated with single drought years. The simulation study found that defoliation reduces both torching and crowning potential, requiring greater surface fire intensity for crown ignition than undefoliated tree crowns with the same crown base height. Single, highly defoliated trees (80%) experienced little or no torching, and moderately defoliated trees (50%) required about twice the surface fire intensity of undefoliated trees to produce the same heat output. For example, at a surface fire intensity of 700 kW/m2 , 99% of the canopy fuel from the undefoliated tree was consumed, leaving 2 kg of foliage on the tree, compared to 81% consumption of a moderately (50%) defoliated tree, leaving 15 kg of foliage. The effects of defoliation were somewhat mitigated by canopy fuel heterogeneity and potential branchwood drying, but these effects were less pronounced than defolation itself. Our study suggests that areas heavily defoliated by western spruce budworm may inhibit crown fire spread and may thus promote non-lethal surface fires

Pennsylvania Folklife Vol. 29, No. 3

• Shuler Family Correspondence • Vestiges of the Markley Family • 30 Years of the Kutztown Folk Festival: A Photo Essay • The Rural Village • Father of the Fraternity: Christopher Schlegel and Rosicrucianism • A Lexical Comparison of Two Sister Languages: Pennsylvania German and Yiddish • Aldes un Neieshttps://digitalcommons.ursinus.edu/pafolklifemag/1087/thumbnail.jp