Canopy, forests

Cronan, C. S. (1984). Biogeochemical responses of forest canopies to acid precipitation. In "Direct and Indirect Effects of Acidic Deposition on Vegetation" (R. A. Linthurst, ed.), pp. 65-79. Butterworth, Boston, MA. 

Lindberg SE, Garten Jr CT. 1988. Sources of sulfur in forest canopy throughfall. Nature 336 148-151. 

St. Louis VL, Rudd JW, Kelly CA, Hall BD, Rolfhus KR, Scott KJ, Lindberg SE, Dong W. 2001. The importance of the forest canopy to fluxes of methyl mercury and total mercury to boreal ecosystems. Environ Sci Technol 35 3089-3098. 

Hg concentrations in forest soils, mosses and fungal fruiting bodies are variable, and are influenced by many factors, such as the extent of forest-based capture of atmospheric Hg deposition, transmission of Hg from the forest canopy to the litter layer whether covered with mosses or not, and type of moss and soil layer conditions and configurations. Within the fungal fruiting bodies, further alternation of the Hg cycle occurs on account of mycelia substrate preferences and Hg allocation to stalk and caps, according to developmental stage. 

Forest canopy interception Derivation of a relationship with precipitation amount and land use... 

Beneath the Chamber of the Desirous Quest is the Hall of the Red Lion, corresponding to Netzach. It has an emerald altar, walls of jade, and a floor of malachite and copper tiles. Seven pillars, three of green marble, three of amber and one of scarlet, support the jade dome that is carved with leaves to resemble a forest canopy. The throne in the east is of coral. The tarot tapestries are X, XIII, XVI, XVII, and XVIII. The chamberlain of this hall is usually connected with the Lordly Ones, the Elven folk from under the hollow hills—perhaps even the elfin queen from the enchanted forest of Brolicade. 

BREEMEN, N. van. 1982. Soil acidification from atmospheric ammonium sulphate in forest canopy throughfall. Nature Volume 299, October 1982. 

In forests, mechanical turbulence is caused by trees, and temperature inversions by the forest canopy. Ventilation inside a forest is complex and not readily described by existing air flow models (Aylor, 1976). 

Lamb, B D. Gay, H. Westberg, and T. Pierce, A Biogenic Hydrocarbon Emission Inventory for the U.S.A. Using a Simple Forest Canopy Model, Atmos. Environ., 27, 1673-1690 (1993). 

Within the framework of the AsiaFlux program, Saigusa et al. (2005) measured the C02 fluxes since 1993 in the forest ecosystem of Takayama using an aerodynamic method to estimate the vertical gradient of C02 concentration and a vortex divergence method to calculate the coefficient of diffusion over the forest canopy. Also, measurements were made of vortex fluxes of sensible heat, water vapor, and C02. 

Dumbauld, R.K., Rafferty, J.E., and Bjourklund, J.R., "Prediction of Spray Behavior Above and Within a Forest Canopy" special report under contract 19-276. USDA For. Service, Pacific N.W. For. and Range Exp. Sta., Portland, Oreg., and For. Pest Management, Davis, Calif., 1977. 

Dumbauld, R.K., J.R. Bjorklund and S.F. Saterlie. 1980. Computer models for predicting aircraft spray dispersion and deposition above and within forest canopies. User s Manual for the FSC BG Computer Program. Report 80-11, H E. Cramer Co., Inc., Salt Lake City, Utah. 

A Grumman Avenger TBM flying approximately 20 m above the forest canopy applied the dyed spray with an emitted volume median diameter (vmd) close to 100 p. The spray mix, an aqueous fenitrothion emulsion, was applied at a rate equivalent to 1.5 1/ha and had a residual volume of 20% after evaporation of the water. Consequently, the evaporated vmd was approximately 58 p. 

Dumbauld, R. K. J. E. Rafferty J. R. Bjorklund "Prediction of spray behavior above and within a forest canopy." Special Report, Contract No. 19-276, Methods Application Group, USDA Forest Service, Davis, CA, 1977. 

Their volatilization from litter on the forest floor will also be appreciable. With the possible exception of carbaryl, their volatilization after being washed into the soil will be relatively low or insignificant because of their low volatility, low Henry s constants, Kh> and/or their high rates of degradation in the soil environment. The rapid disappearance of the phenoxy herbicides (2, 31) and the insecticide, fenitrothion (28) from vegetation and the forest floor is supporting evidence that volatilization is an important pathway for loss of applied pesticides from the forest canopy and litter on the forest floor. 

As a consequence of the very rough surface of a coniferous canopy (which in no way approaches a plane structure) thermal fluxes from these surfaces are relatively small ie. forest canopy surfaces are relatively cooler than the surfaces of farm crops (18). The spire like structure of the crown result in daytime temperature gradients immediately above the canopy surface which are small and wind speed gradients which are relatively large. It should he anticipated that buoyant (free convective) eddies generated by vertical temperature gradients will be relatively unimportant and that wind speed gradients will provide the major source of eddy currents. 

Field observations during aerial spray applications have demonstrated that anywhere from 15-75% of the pesticide mix admitted from the aircraft reaches the forest canopy (2). In some cases under unstable conditions, "on-target" deposit was less than 2% of the total emitted material. The portion of the spray deposit that does not land "on-target" (i.e. on conifer foliage) may be transported to aquatic and other non-target habitats. Overall, the amount of adjuvants in the mixes that deposits onto... 

Hurd MK, Perry S, Perry WB. 1996. Nontarget effects of a test application of difluben-zuron to the forest canopy on stream macroinvertebrates. Environ Toxicol Chem 15 1344-1351. 

In general these results suggest that the character of the forest canopy will prove to be one of the most important factors controlling the distribution of aerially applied slow release formulations under woodland canopies and the ultimate gradients of pheromone vapor under them. 

Table IV. Concentrations of disparlure vapor between 0.3 and 17 meters height under a microcapsule-treated forest canopy at Elk Neck, Maryland, during daylight hours on August 18, 1976.

The final step in the testing program evaluates the performance of material aerially applied on small field plots. Since this procedure aims to define the physico-chemical characteristics of each product, not the biological effect, the following two processes are monitored 1. Residual pheromone from formulation collected in the field zero to forty days post application and 2. atmospheric concentration of TDAL in the forest canopy. 

Several steps in implementation of specific urban dynamics and energetics have already been achieved by the HIRLAM/HARMONIE community. Enviro-HIRLAM considers a surface improved description for urban areas roughness, albedo, urban heat sources (Eaklanov et al. 2008). Properties of urban aerosol used to modify the albedo characteristics and the effective radius of cloud droplets for the SW radiation (in the HIRLAM radiation scheme). In FUMAPEX two other more sophisticated urban schemes EEP (Martilli et al. 2002) and SM2-U modules (Dupont and Mestayer 2006) were tested. They are more expensive computationally. Town energy balance (TEE) module (Masson 2000) is a part of SURFEX, available in the HARMONIE framework. Handling of the finest-scale details of momentum fluxes in town (forest) canopy could be developed. 

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