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Students benefit in many ways by taking field trips to forests. Improved academic performance, increased participation in outdoor recreation, and a better grasp of natural resources management are some of the advantages. However, trips are not easy for teachers to organize and lead. Declining budgets, on-campus schedules, and standards of learning are but a few of the constraints. With this in mind we studied the use of forest field trips among high school science teachers in the Southern Piedmont of the United States. We asked them if they have ever led a field trip to a forest for instructional purposes and measured their perceived constraints, teaching characteristics, natural resources training and extra-curricular activities, and proximity of their school to a forest. Binary logistic regression was used to model the relationship between these data and whether a teacher had taken a class on a forest field trip. Teachers also were asked to comment about trip constraints. Under half had led a forest field trip and qualitative data suggest that constraints such as time, money, and standardization are significant. However, model results indicate that walking distance to a forest, confidence in teaching topics related to forests, and participation in natural resources school programs predict field trip use (chi[superscript 2] = 127.81). Findings will help develop strategies for incorporating forest field trips into secondary science curriculum.

Quantification of the heterotrophic component of total soil respiration is important for estimating forest carbon pools and fluxes, and for understanding carbon dynamics associated with stand development and silvicultural management. We measured the proportion of heterotrophic respiration (R H ) to total soil respiration (R S ) in extensively managed loblolly pine ( Pinus taeda L.) stands of four age classes in the Piedmont physiographic province of Virginia. Our objectives were to evaluate the influence of stand age and seasonality on the proportion of R H to R S (R H :R S ). R H was partitioned using root exclusion cores, and both R S and R H were measured 90 days following installation of cores for five seasons. Repeated measures analysis revealed that stand age and measurement season each had a significant effect on R H :R S ( P < 0.001), but that there were no interactive effects ( P = 0.202). Mean R H :R S during the 12-month study declined with stand age, and were 0.82, 0.73, 0.59, and 0.50 for 3-year-old, 9-year-old, 18- year-old, and 25-year-old stands, respectively. Across all age classes, the winter season had the highest mean R H :R S of 0.85 while summer had the lowest of 0.55. This study provides estimates of R H :R S in managed loblolly pine systems, and demonstrates the need to consider the impact of stand age and seasonal patterns when estimating net annual carbon (C) budgets of forest ecosystems and to identify the point at which plantations switch from functioning as C sources to a C sinks. [ABSTRACT FROM AUTHOR]

Abstract: Clonal forestry offers the opportunity to increase yields, enhance uniformity and improve wood characteristics. Intensive silvicultural practices, including fertilization, will be required to capture the full growth potential of clonal plantations. However, variation in nutrient use efficiency that exists among clones could affect growth responses. Our research objective was to determine the range of growth response and stem form quality due to fertilization in clones of Pinus taeda. A split-plot experimental design was used, with the whole plots being two levels of fertilizer application (fertilizer versus control) and the split plot factor being 25 clones. Whole plot treatments were blocked and replicated four times. Six years after planting and five years after fertilizer application, a repeated measures analysis showed fertilizer-by-time and clone-by-time interactions affected volume (p <0.10). Clone-by-fertilizer interactions were observed for tree height, branch traits, and a metric of foliar display. These interactions were primarily due to scale-effect phenomena rather than rank shifts. The magnitude of fertilizer responses observed in a small number of genotypes suggests that knowledge of fertilizer responses in widely deployed genotypes, if developed prior to mid-rotation, may better optimize management of single-clone blocks. Our results further indicate that a range of possibilities exist for the design and application of clone-specific precision silvicultural systems. [ABSTRACT FROM AUTHOR]