The balance of planting and mortality in a street tree population

Street trees have aesthetic, environmental, human health, and economic benefits in urban ecosystems. Street tree populations are constructed by cycles of planting, growth, death, removal and replacement. The goals of this study were to understand how tree mortality and planting rates affect net population growth, evaluate the shape of the mortality curve, and assess selected risk factors for survival. We monitored a street tree population in West Oakland, CA for 5 years after an initial inventory (2006). We adapted the classic demographic balancing equation to quantify annual inputs and outputs to the system, tracking pools of live and standing dead trees. There was a 17.2 % net increase in live tree counts during the study period (995 in 2006, 1166 in 2011), with population growth observed each year. Of the live trees in 2006, 822 survived to 2011, for an annual mortality rate of 3.7 %. However, population growth was constrained by high mortality of young/small trees. Annual mortality was highest for small trees, and lower for mid-size and large trees; this represents a Type III mortality curve. We used multivariate logistic regression to evaluate the relationship between 2011 survival outcomes and inventory data from 2006. In the final model, significant associations were found for size class, foliage condition, planting location, and a multiplicative interaction term for size and foliage condition. Street tree populations are complex cultivated systems whose dynamics can be understood by a combination of longitudinal data and demographic analysis. Urban forest monitoring is important to understand the impact of tree planting programs.     

Differences in fish harvest,fishing effort,and angling guard activities between urban and natural fishing grounds

Recreational fishing is a very popular outdoor leisure activity. Assessing differences in basic metrics in recreational fishing on different types of fishing grounds is very important for effective fisheries management. This study aimed to discover how basic metrics in recreational fishing (harvest, fishing effort, angling guard activities) differ between urban fishing grounds (located in a densely populated city) and natural fishing grounds (located in the countryside). Data were obtained from individual angling logbooks collected by the Czech Fishing Union on the River Elbe and the River Vltava (Prague and Central Bohemia, Czechia, Central Europe). Study shows that urban and natural fishing grounds showed significant differences in basic metrics in recreational fishing. Urban fishing grounds displayed higher fish harvest in general and higher dominance of intensively stocked fish species in catches of anglers (mainly common carp Cyprinus carpio). High harvest rates of common carp can be mostly explained by intensive fish stocking. The only fish species that showed higher harvest on natural fishing grounds were large-growing piscivorous fish with high ecological demands. However, anglers were harvesting larger fish (average body weight) on natural fishing grounds. In addition, fishing effort was similar on both types of fishing grounds. Inversely, angling guards were more active on natural fishing grounds. In conclusion, differences in basic fisheries metrics between urban and natural fishing grounds seem to be partially driven by intensive fish stocking.

     

General growth balance method: A reformulation for populations open to migration

This paper proposes a reformulation of the general growth balance method for estimating census and registration completeness so as to make it applicable even to populations that are affected by migration. It also discusses a new procedure of line fitting that could be useful in countries where the input data are severely affected by age misreporting. The method is applicable to countries where data on age distribution of the population are available for two points in time from either censuses or surveys. Following closely the original proposal of Brass, it involves adjusting the 'partial' birth rates for age-specific disturbances from growth and migration rates. Beyond correcting the death rates, the method is useful in inferring the relative completeness of the censuses, and in deriving a robust estimate of birth rate under certain conditions. The application of the method is illustrated using the example of the male population of the Indian state of Uttar Pradesh for the period 1981 to 1991.     

Trends in Spouses’ Shared Time in the United States, 1965–2012

Despite major demographic changes over the past 50 years and strong evidence that time spent with a spouse is important for marriages, we know very little about how time with a spouse has changed—or not—in the United States. Using time diary data from 1965–2012, we examine trends in couples’ shared time in the United States during a period of major changes in American marriages and families. We find that couples without children spent more total time together and time alone together in 2012 than they did in 1965, with total time and time alone together both peaking in 1975. For parents, time spent together increased between 1965 and 2012, most dramatically for time spent with a spouse and children. Decomposition analyses show that changes in behavior rather than changing demographics explain these trends, and we find that the increases in couples’ shared time are primarily concentrated in leisure activities.     

Matching across Space: Evidence from Finland

Abstract. This paper takes a matching approach to local labour markets in Finland. The monthly data comprise 120 Local Labour Office areas over a 12 year period between January 1991 and August 2002. The basic matching function is extended to account for spatial spillovers across borders. The role of population density in the matching process is also examined. According to the results, there is a congestion effect among job seekers in the local labour markets, which is further strengthened by spatial spillovers. The results also indicate that job seekers from neighbouring areas cause additional heterogeneity in the matching process in densely populated areas, which decreases the matching efficiency in these areas.     

Testing monotonicity of pricing kernels

The behaviour of market agents has been extensively covered in the literature. Risk averse behaviour, described by Von Neumann and Morgenstern (Theory of games and economic behavior. Princeton University Press, Princeton, 1944) via a concave utility function, is considered to be a cornerstone of classical economics. Agents prefer a fixed profit over an uncertain choice with the same expected value, however, lately there has been a lot of discussion about the empirical evidence of such risk averse behaviour. Some authors have shown that there are regions where market utility functions are locally convex. In this paper we construct a test to verify uncertainty about the concavity of agents’ utility function by testing the monotonicity of empirical pricing kernels (EPKs). A monotonically decreasing EPK corresponds to a concave utility function while a not monotonically decreasing EPK means non-averse pattern on one or more intervals of the utility function. We investigate the EPKs for German DAX data for the years 2000, 2002 and 2004 and find evidence of non-concave utility functions: the null hypothesis of a monotonically decreasing pricing kernel is rejected for the data under consideration. The test is based on approximations of spacings through exponential random variables. In a simulation we investigate its performance and calculate the critical values (surface).     

Assessing Cultural Competence in a BSW Student Population

Bachelor’s level social workers serve a population that is becoming more diverse. Social work educators must respond with adapted teaching methods, theories, and exercises to reflect the growing need for cultural competence in our practitioners. The 2015 Educational Policy and Accreditation Standards (EPAS) outline the knowledge, value, and skills competencies central to social work education. These competencies include thorough integration of cultural competence in social work education; the ways in which this content is taught likely vary greatly between programs. This study assessed whether students gained competence as a result of taking a bachelor’s level social work (BSW) course in cultural diversity at a mid-sized public university. Furthermore, the study assessed whether their level of competence was related to student demographics, such as being from an urban or rural community. One hundred twenty-three students completed the California Brief Multicultural Competence Scale (CBMCS) at the beginning and end of a course specifically dedicated to cultural competence. Results indicate that the course itself is effective in increasing significantly student’s self-reported cultural competence. Study results lay the foundation for future research that will (1) assess more broadly the implications of a specific cultural competence course and (2) aid in the development of a social work-specific measure of cultural competence.