Apiculture and forestry (bees and trees)

Honey bees are found associated with forests globally. Flowers of forest trees provide subsistence for honey bees and the trees physically provide shelter for a swarm or bee hive. Forest management and beekeeping have each had a long history both in the United States and globally, but have seldom been integrated or studied in a systematic fashion. Purposeful plantings of trees, as in agroforestry systems, could be designed to favor bee forage or hive protection.Tree growing and beekeeping can easily be combined for several reasons. Both are sustainable on land that is hilly or otherwise less desirable for other agricultural purposes. Both require labor intermittently, and can be sustained while the grower/beekeeper is busy with other farming occupations. Bee hives require very little space, while the bees themselves can forage in a radius of 4 to 5 km. Hives may be located within or near a tree plantation, and utilize both the trees and surrounding other flowering plants for forage. Combining forestry and beekeeping provides annual honey bee products (e.g. honey, beeswax) to supplement income from a landowner's long term forest managements. In areas like Kentucky, where more than half of the forest landowners own 4 ha or less of commercially valuable woodland, it is important to produce economic benefit from those lands without harvesting all the trees. Combining bees and trees is one way of accomplishing this goal. This paper addresses several important known bee-tree interactions which need more systematic study.     

Changing technology for training irrigation managers

This article describes developments in microcomputer and video-disc technology which may be used in the training of managers for irrigation projects.     

Evaporation from fetch-limited water bodies

An analytic model to calculate evaporation from fetch-limited water bodies is described. By modifying the surface boundary condition to an analytic solution to the advection-diffusion equation for specific humidity in the air flow over a water body, we are able to solve for the entire specific humidity field q (x, z) from a single measurement of humidity, surface temperature, and wind speed. Comparisons of model predictions with measurements from Rushy Billabong, a small turbid lake, over a 146 day period show that on average the model underestimates evaporation rates by 12%. We believe that the evaporation shortfall is due to the downwind advection of heat within the billabong when the billabong is highly stratified in temperature. When the thermal stratification is weak, the advection of heat within the water column is less important and the model is an accurate predictor of evaporation.     

Microparticle dispensers for the controlled release of insect pheromones

The potential utility of micrometer-sized particles as controlled-release devices for the volatilization of insect pheromones for mating disruption applications is evaluated in this study for two pheromone/model compound systems (codlemone/1-dodecanol and disparlure/1,2-epoxyoctadecane). To expedite the measurement of release rates from these particle devices, two techniques based on thermogravimetric analysis (TGA) have been exploited: isothermal TGA (I-TGA) at elevated temperatures (40-80 degrees C) with N(2) convection and volatilization temperature (VT) by dynamic TGA. A correlation between these two methods has been established. Samples that exhibit a higher VT provide a lower release rate from a particle substrate. Using these techniques, it has been demonstrated that chemical interactions between adsorbed liquids and particle surfaces may play a small role in defining release characteristics under conditions of low surface area, whereas parameters associated with total surface area and micropore structure appear to be much more significant in retarding evaporation for uncoated particles containing an adsorbed liquid. Additional regulation of release rates was achieved by coating the particle systems with water-soluble or water-dispersible polymers. By careful selection of particle porosity and coating composition, it is envisioned that the evaporation rate of pheromones can be tailored to specific insect control applications.     

Experimental acidification of Little Rock Lake,Wisconsin: The first four years of chemical and biological recovery

Little Rock Lake was experimentally acidified in 1984–1990 during which sulfuric acid was added to one basin, decreasing pH from 6.1 to 5.6, 5.1 and 4.7. The lake has been allowed to recover without manipulation since autumn 1990. By the third year of recovery, ～40% of the change necessary to return to pre-acidification values of pH, acid neutralizing capacity (ANC), sulfate (SO₄ ^2?) and calcium (Ca²⁺) had occurred. During recovery years 1–2, ANC was closely predicted by models based on acidification phase observations, but recovery during years 3–4 was slower than predicted. A possible explanation for the slowed recovery is acidification of the upper 0–5 cm of sediment, which acts as a sink for the ANC generated via SO₄ ^2? reduction, the primary recovery mechanism. Trends for Zooplankton did not follow pH recovery very closely. Species diminished by acidification (e.g. Keralella cochlearis, Daphnia dubia) have not recovered, but species that dominated the community at pH 4.7 (e.g. K. taurocephala, D. catawba) have not maintained high populations. The time required for the Zooplankton community to recover to pre-manipulation conditions is uncertain. Delays also have been observed for the mayfly species Caenis, which had disappeared at pH 4.7. In contrast, reproductive success of largemouth bass (Micropterus salmonides) mirrored that observed during acidification; egg hatch and survival of young-of-the-year to autumn recurred when pH exceeded response levels documented during acidification. Overall, recovery has not closely followed the pattern predicted by acidification responses.     

Fish assemblage production estimates in Appalachian streams across a latitudinal and temperature gradient

Production of biomass is central to the ecology and sustainability of fish assemblages. The goal of this study was to empirically estimate and compare fish assemblage production, production‐to‐biomass (P/B) ratios and species composition for 25 second‐ to third‐order streams spanning the Appalachian Mountains (from Vermont to North Carolina) that vary in their temperature regimes. Fish assemblage production estimates ranged from 0.15 to 6.79 g m^?2 year^?1, and P/B ratios ranged from 0.20 to 1.07. There were no significant differences in mean assemblage production across northern cold‐water, southern cold‐water and southern cool‐water streams (p = .35). Two warm‐water streams, not included in these comparisons, had the highest mean production and biomass values. Mean assemblage P/B was significantly higher in northern cold‐water streams relative to southern cold‐water and cool‐water streams (p = .01). Species evenness in production declined with stream temperature and differed significantly across the lower latitude cold‐water, cool‐water and warm‐water streams and the higher latitude (i.e. more northern) cold‐water streams. Our fish assemblage production estimates and P/B ratios were both lower and higher compared to previously published estimates for similar stream habitats. This study provides empirical fish assemblage production estimates to inform future research on southern Appalachian streams and on the potential impacts of varying temperature regimes on cold‐water, cool‐water and warm‐water fish production in the coming decades as climate change continues to threaten fish assemblages.     

Aerially applied methylcyclohexenone-releasing flakes protect Pseudotsuga menziesii stands from attack by Dendroctonus pseudotsugae

We tested methylcyclohexenone (MCH), an anti-aggregation pheromone for the Douglas-fir beetle (Dendroctonus pseudotsugae), for protection of Douglas-fir (Pseudotsuga menziesii) stands by applying MCH-releasing polymer flakes by helicopter twice during summer 2006 to five 4.05-ha plots in the State of Washington, USA. Five similar plots served as untreated controls. We assessed D. pseudotsugae flight into study plots using baited pheromone traps, and tallied D. pseudotsugae attack rates on all P. menziesii trees in 2005 and 2006. We also measured stand basal area and incorporated that as an explanatory variable in the analysis. Significantly fewer D. pseudotsugae were trapped in treated plots than in control plots, and significantly fewer P. menziesii trees were attacked in treated plots than in control plots. The attack rate in untreated stands was nearly 10 times that of treated plots, and stands with higher basal area were significantly more likely to be attacked by D. pseudotsugae than were stands of lower basal area. Attack rates in 2006 and 2005 were significantly correlated, regardless of treatment.