Mixture Of Trees Research Articles

Mixed Tree and Spacial Representations of Dissimilarity Judgments

Whereas much previous research, focusing on the comparative fit at the aggregate level, has shown that either tree or spatial representations of dissimilarity judgments may be appropriate, we investigate whether there exist classes of subjects differing in the extent to which dissimilarity judgments are better represented by additive tree or spatial multidimensional scaling models. We develop a mixture model for the analysis of dissimilarity data that entails both representation and measurement model components. The latter involves distributional assumptions on the measurement error and enables estimation by maximum likelihood. The former component allows dissimilarity judgments to be represented either by an additive tree structure or by a spatial configuration, or a mixture of both. To investigate the appropriateness of additive tree versus spatial representations, the model is applied to twenty empirical data sets. We compare the fit of our model with that of aggregate additive tree and spatial models, as well as with mixtures of additive trees and mixtures of spatial configurations, respectively. We formulate some empirical generalizations on the relative importance of tree versus spatial structures in representing dissimilarity judgments.

Vegetation–Climate Feedbacks in the Conversion of Tropical Savanna to Grassland

Tropical savannas have been heavily impacted by human activity, with large expanses transformed from a mixture of trees and grasses to open grassland and agriculture. The National Center for Atmospheric Research (NCAR) CCM3 general circulation model, coupled with the NCAR Land Surface Model, was used to simulate the effects of this conversion on regional climate. Conversion of savanna to grassland reduced precipitation by approximately 10% in four of the five savanna regions under study; only the northern African savannas showed no significant decline. Associated with this decline was an increase in the frequency of dry periods within the wet season, a change that could be particularly damaging to shallow-rooted crops. The overall decline in precipitation is almost equally attributable to changes in albedo and roughness length. Conversion to grassland increased mean surface air temperature of all the regions by 0.5°C, primarily because of reductions in surface roughness length. Rooting depth, which decreases dramatically with the conversion of savanna to grassland, contributed little to the overall effect of savanna conversion, but deeper rooting had a small positive effect on latent heat flux with a corresponding reduction in sensible heat flux. The authors propose that the interdependence of climate and vegetation in these regions is manifested as a positive feedback loop in which anthropogenic impacts on savanna vegetation are exacerbated by declines in precipitation.

Changes in Soil Chemical and Physical Characteristics in Japanese Cypress (Chamaecyparis obtusa Endl.) Stands by Mixture of Deciduous Broad-leaved Trees in the Northern Kanto Region of Japan

In order to clarify the effects of a mixture of deciduous broad-leaved trees on soil fertility, we investigated litter biomass accumulation, mineral soil chemical and physical characteristics, characteristics of nitrogen mineralization, and the mutual relationships between them in Japanese cypress (Chamaecyparis obtusa) stands mixed with deciduous broad-leaved trees at different ratios (mixture ratio; MR = 0, 16, 33, 43, 100% by basal area) in the northern Kanto region of Japan. Litter biomass in the forest floor and mineral soil was 19.1 Mg ha−1 in MR 0% and decreased approximately 60 % in MR 33%, MR 43% and MR100%. The permeability at 0–5 cm soil depth in MR100% was twice as much as that in MR 0%. Increases in soil permeability were likely due to larger soil pores in the higher MR with much accumulated deciduous broad-leaves. At 0–5 cm soil depth, the differences in carbon concentration among the plots were not clear. On the other hand, carbon concentrations at 5–10 cm depth increased from 90 g kg−1 to 147 g kg−1 with increases in MR from 0% to 100%. Concentrations of exchangeable bases increased two to four times with increases in MR from 0 to 100% at 0–10 cm depth. Soil pH (H2O) generally increased with increases in MR at each depth. The rates of net nitrogen mineralization at 0–5 cm depth in vitro increased from 25 to 87 mg kg−1 2 weeks−1 with increases in MR from 0 to 100%. However, increases in nitrification with increases in MR were not clear compared with nitrogen mineralization. These results indicated that a mixture of deciduous broad-leaved trees in a Japanese cypress stand was effective in preventing soil fertility decline.

Are mixtures of aspen and white spruce more productive than single species stands?

In boreal mixedwood forests, aspen (Populus tremuloides) and white spruce (Picea glauca) commonly grow in mixture. These species may avoid competition through differential shade tolerance, physical separation of canopies, phenological differences, successional separation, and differences in soil resource utilization. Aspen may also be able to positively affect the growth of white spruce by improving litter decomposition and nutrient cycling rates, controlling grass and shrub competition, ameliorating environmental extremes, and reducing pest attack. These positive relationships likely make mixed-species stands more productive than pure stands of the same species. The evidence regarding the productivity of pure versus mixed aspen/white spruce stands in natural unmanaged forests is examined in this paper. Key words: Tree mixture; productivity; boreal mixedwoods; aspen; white spruce

Carbon and water vapor exchange of an open-canopied ponderosa pine ecosystem

Eddy covariance measurements of carbon dioxide and water vapor exchange were made above a ponderosa pine ( Pinus ponderosa Dougl. ex P. and C. Laws.) forest located in a semiarid environment in central Oregon. The stand is a mixture of old-growth and young trees. Annual net carbon gain by the ecosystem (NEE) was 320 ± 170 gC m −2 year −1 in 1996 and 270 ± 180 gC m −2 year −1 in 1997. Compared to boreal evergreen forest at higher latitudes, the pine forest has a substantial net carbon gain (150 ± 80 gC m −2 year −1 in 1996 and 180 ± 80 gC m −2 year −1 in 1997) outside the traditionally defined growing season (from bud swell in early May (Day 125) to partial leaf-off in late September (Day 275)). Carbon assimilation continued to occur in the relatively mild winters, though at a slower rate (April, maximum leaf level assimilation ( A max) of 6–9.5 μmol m −2 leaf s −1), and ecosystem respiration was relatively low (∼1.6 ± 0.1 gC m −2 day −1). In the growing season, although photosynthetic capacity was large (July, A max = 16–21 μmol m −2 leaf s −1), carbon assimilation was constrained by partial stomatal closure to maintain a sustainable water flow through the soil-plant system, and ecosystem respiration was large (3.5 ± 0.1 and 4.3 ± 0.1 gC m −2 day −1 in growing season of 1996 and 1997, respectively) because of high air and soil temperatures. Despite large changes in evaporative demand over just a few days (VPD changing from 0.5 to 3.5 kPa), the ecosystem water use was remarkably constant in summer (∼1.6–1.7 mm day −1). Such homeostasis is most likely another result of stomatal control. Interannual variations in climate had a large influence on the ecosystem carbon balance. In summer 1997, an El Niño year, precipitation was more frequent (17 days with 33 mm of rain) than in summer 1996 (5 days with 5 mm of rain), and the net ecosystem exchange was substantially lower in July to September 1997 (10 ± 60 gC m −2) than during the equivalent period in 1996 (100 ± 60 gC m −2). Although temperatures between years were similar, the carbon assimilation in 1997 was offset by increased respiration, probably because soils were more frequently wet, encouraging microbial respiration.

Comparative feeding ecology of red (Cervus elaphus) and roe deer (Capreolus capreolus) in Scottish plantation forests

AbstractDiets of red Cervus elaphus and roe Capreolus capreolus deer in Scottish plantation forests were assessed by botanical and chemical analyses of 144 rumen samples. Samples were taken for summer and winter from four forests with a range of deer densities and ratios. Red deer ate mainly grasses in summer, and a mixture of sedges, rushes, grasses and heaths (ericoid plants) in winter. Roe deer ate predominantly forbs (herbaceous plants other than graminoids) in summer, and a mixture of forbs, heaths and tree and shrub browse in winter. The two species ate significantly different quantities of forbs and grasses (P < 0.001). Both species ate more grasses and forbs in summer, and more heaths in winter (P < 0.05). There were few differences between forests for either red or roe deer in diet composition or its seasonal variation. Washed rumen contents of roe deer contained more nitrogen than did those of red deer (P < 0.05) in both seasons, and both species contained more nitrogen in summer than in winter (P < 0.05). Proportions of the main plant categories within rumens were compared with their abundance recorded in the ground flora. These comparisons showed roe deer to be highly selective, whilst red deer ate plants in proportions similar to their availability. Niche overlap increased and dietary niche breadths widened during the winter. The main overlap was for heaths Calluna vulgaris and Vaccinium myrtillus in winter. However, C. vulgaris is widespread and common and competition was considered to be more likely for forbs and possibly V. myrtillus: the use of some forb species by red deer in summer may limit their availability to roe deer in winter, when they remain an important dietary item. Consideration of the different digestive specializations of the two species suggested that any dietary competition is likely to affect roe deer more than red deer.

Comparative feeding ecology of red (Cervus elaphus) and roe deer (Capreolus capreolus) in Scottish plantation forests

Diets of red Cervus elaphus and roe Capreolus capreolus deer in Scottish plantation forests were assessed by botanical and chemical analyses of 144 rumen samples. Samples were taken for summer and winter from four forests with a range of deer densities and ratios. Red deer ate mainly grasses in summer, and a mixture of sedges, rushes, grasses and heaths (ericoid plants) in winter. Roe deer ate predominantly forbs (herbaceous plants other than graminoids) in summer, and a mixture of forbs, heaths and tree and shrub browse in winter. The two species ate significantly different quantities of forbs and grasses (P < 0.001). Both species ate more grasses and forbs in summer, and more heaths in winter (P < 0.05). There were few differences between forests for either red or roe deer in diet composition or its seasonal variation. Washed rumen contents of roe deer contained more nitrogen than did those of red deer (P < 0.05) in both seasons, and both species contained more nitrogen in summer than in winter (P < 0.05). Proportions of the main plant categories within rumens were compared with their abundance recorded in the ground flora. These comparisons showed roe deer to be highly selective, whilst red deer ate plants in proportions similar to their availability. Niche overlap increased and dietary niche breadths widened during the winter. The main overlap was for heaths Calluna vulgaris and Vaccinium myrtillus in winter. However, C. vulgaris is widespread and common and competition was considered to be more likely for forbs and possibly V. myrtillus: the use of some forb species by red deer in summer may limit their availability to roe deer in winter, when they remain an important dietary item. Consideration of the different digestive specializations of the two species suggested that any dietary competition is likely to affect roe deer more than red deer.

Moose, Trees, and Ground-Living Invertebrates: Indirect Interactions in Swedish Pine Forests

The role of moose in structuring the boreal forest ecosystem has been studied extensively in recent years. This research has focused mainly on the effects of moose on vegetation and soil dynamics. However, the extent to which these effects influence animal communities has received little attention. We studied how invertebrate assemblages on the forest floor of two Swedish pine forests were affected by the presence of moose. Our approach was to trap invertebrates using pitfall traps in unbrowsed exclosures and browsed reference plots, estimate the percentage cover of herb-layer plants, measure the height and density of tree species, and measure the accumulation of leaf litter. The effect of moose on tree strata differed between the two areas. In Sunnas, where the stand was a mixture of deciduous trees and pines, the main effect of moose was to eliminate most of the deciduous trees from the canopy. Here the amount of deciduous leaf litter was ten times higher in unbrowsed exclosures compared with browsed plots. The stands on the dry sites in the other area, Furudal, were almost pure pine. Here, moose browsing reduced the density of taller pines, but increased the number of pine saplings. At Sunnas, the herb-layer plant cover did not differ between browsed and unbrowsed plots. However, there was a difference between exclosures and browsed plots in terms of the ground-dwelling invertebrate assemblage. Number of individuals of most invertebrate groups that differed between exclosures and browsed plots were higher in unbrowsed plots and the total number of invertebrates was also higher in unbrowsed plots, but diversity of invertebrate fauna was higher in browsed plots. At Furudal both the vegetation and invertebrate assemblages differed between browsed and unbrowsed plots. Browsed plots had a higher cover of ground lichens, while unbrowsed plots had more mosses. Among the invertebrate taxa that differed between treatments, the number favored by browsing and the number disfavored by browsing were roughly equal, and diversity was not affected by moose. We suggest that by affecting the density and composition of tree species, moose indirectly influenced the structure of invertebrate communities. At Sunnas, the reduction in the amount of deciduous leaf litter was probably the key effect. Vegetation was not affected much, but the differences in litter layer composition had affected the microclimate on the forest floor while also providing an important additional trophic resource and habitat for ground-dwelling invertebrates. At Furudal the main effect of moose was to reduce the density of the pine canopy, thus increasing the amount of light penetrating to the forest floor. As a consequence, the floral composition and microclimate was altered which, in turn, affected the invertebrate fauna.

High Diversity of Saproxylic Beetles in a Hemiboreal Mixed Forest Reserve in the south of Norway

Altogether 335 species of saproxylic beetles were collected by Malaise, window and emergence traps in a 33 ha forest reserve in southern Norway, during the years 1992 - 1997. Most species are associated with deciduous trees, particularly oak, and the majority depend on decayed wood or fungi. The forest is a mixture of Norway spruce and deciduous trees and is characterized as being very close to a primeval forest. Sixty - two species of the collected beetles are assumed to be threatened or rare in Scandinavia, 52 species are on the Red Data List in Sweden and 43 species are suggested for a similar list in Norway. Fifteen species are on a list of species threatened in the Nordic region. Compared with other thoroughly sampled forest reserves in Fennoscandia, the forest investigated had one of the richest saproxylic beetle communities known to date. The main reasons for this are assumed to be the abundance of dead wood, the diverse tree composition and the fact that the area had been inaccessible for forest harvesting due to the lack of transportation for timber.

Mixtures of (constrained) ultrametric trees

This paper presents a new methodology concerned with the estimation of ultrametric trees calibrated on subjects' pairwise proximity judgments of stimuli, capturing subject heterogeneity using a finite mixture formulation. We assume that a number of unobserved classes of subjects exist, each having a different ultrametric tree structure underlying the pairwise proximity judgments. A new likelihood based estimation methodology is presented for those finite mixtures of ultrametric trees, that accommodates ultrametric as well as other external constraints. Various assumptions on the correlation of the error of the dissimilarities are accommodated. The performance of the method to recover known ultrametric tree structures is investigated on synthetic data. An empirical application to published data from Schiffman, Reynolds, and Young (1981) is provided. The ability to deal with external constraints on the tree-topology is demonstrated, and a comparison with an alternative clustering based method is made.

Early Growth Performance of Mango and Cashew Coplanted with Four Nitrogen Fixers in a Tropical Alfisol

A five year field experiment was conducted to get information which will facilitate the scientific development of tree mixtures in an agroforestry system with two fruit trees viz., mango (Mangifera indica L.) and cashew (Anacardium occidentale L.) and four tropical nitrogen fixers viz., Acacia auriculiformis, Acacia holosericea, Casua-rina equisetifolia and Leucaena leucocephala. Observations on biometrics and edaphic parameters were recorded. Enhanced growth of cashew and mango was observed when coplanted with casuarina and leucaena, respectively. The enhanced height growth of cashew by 25% is recorded when interplanted with casuarina and plant girth (10.8 cm) was maximum when interplanted with leucaena. About 11% increase in height growth of mango was registered when interplanted with leucaena. The investigation identified two nitrogen fixers namely casuarina and leucaena for coplanting in cashew and mango orchards, respectively in the initial establishment Stage.

Associative effects in vitro of mixtures of tropical fodder trees

Previous work in animal nutrition has focused on single foods and assumed additivity during in vitro fermentation. In the tropics, farmers are likely to offer mixtures of foods, including tree fodders, which may not be simply additive in nutritional terms. There is little information about the nutritional interactions between tropical foods. The objective of this research was to test the existence of associative effects of mixtures of tropical fodder tree leaves.

Magnitudes and seasonal patterns of energy, water, and carbon exchanges at a boreal young jack pine forest in the BOREAS northern study area

Seasonal patterns of the energy balance of a young jack pine site near Thompson, Manitoba, in the summer of 1994 are reported. The experiment was part of the Boreal Ecosystem‐Atmosphere Study (BOREAS), and it ran from May 24 to September 19. The average tree density was 4.4 trees m−2, but there was substantial spatial variation associated with three primary vegetation patterns: dense cover of short trees, sparse cover of tall trees, and a mixture of short and tall trees. The frequency distribution of tree heights was bimodal with peaks at 1 and 2 m and a range from 0.3 to 5.7 m. The average tree height was 2.3 m. The daily average photosynthetically active radiation albedo was conservative, varying from 0.054 under clear‐sky conditions to 0.051 under cloudy skies. The shortwave albedo was 0.136 under clear‐sky conditions and decreased by 1% following rain; the presence of smoke over the site increased it by 1%. Heat storage in the soil, trees, and air was an important component of the energy balance throughout the season with soil heat flux comprising the bulk of the total storage. On the average, for the whole experimental period, the sensible heat flux was approximately twice the latent heat flux (Bowen ratio ≈2). The average daily energy balance closure varied from 85% before day‐of‐year (DOY) 200 to 95% after DOY 200. As a result of problems with the measurement of the net CO2 flux above the canopy under stable nighttime conditions, all nighttime values were modeled. The typical diurnal pattern of net CO2 flux shows maximum uptake by the surface in the morning and a gradual decrease through the afternoon. For the whole field season of 118 days, the site fixed 224 g m−2 of carbon.

Problems Associated with the Artificial Flooding of Floodplain Forests in an Industrial Region in Germany

This paper considers problems associated with the artificial flooding of floodplain forests in an industrial region in central Germany. During the past eight centuries river regulation has reduced flooding to an extent dependent on local conditions. The lack of flooding has caused a new pedo-hydrological regime. Typical tree mixtures in the floodplain forests of oak, ash, elm and maple have changed over the last 120 years so that ash and maple now dominate. Sediments of the rivers WeiBe Elster and Mulde were found to be contaminated by industrial pollutants, especially with heavy metals such as Cd, Zn, Co and Cr. Atmospheric pollution and the deposition of dust and gas contaminated by heavy metals over the last 100 years have been responsible for serious soil contamination. There is a danger of the migration of these heavy metals through the floodplain sediments and soils into groundwater. Artificial flooding is one method of re-introducing natural conditions to floodplains and their forests. Our investigations of the migration behaviour of contaminants, using sequential leaching procedures, have demonstrated that a high

Fluxes of carbon, water and energy over Brazilian cerrado: an analysis using eddy covariance and stable isotopes

ABSTRACTWe present the energy and mass balance of cerrado sensu stricto (a Brazilian form of savanna), in which a mixture of shrubs, trees and grasses forms a vegetation with a leaf area index of 1·0 in the wet season and 0·4 in the dry season. In the wet season the available energy was equally dissipated between sensible heat and evaporation, but in the dry season at high irradiance the sensible heat greatly exceeded evaporation. Ecosystem surface conductance gs in the wet season rose abruptly to 0·3 mol m−2 s−1 and fell gradually as the day progressed. Much of the total variation in gs was associated with variation in the leaf‐to‐air vapour pressure deficit of water and the solar irradiance. In the dry season the maximal gs values were only 0·1 mol m−2 s−1. Maximal net ecosystem fluxes of CO2 in the wet and dry season were –10 and –15 μmol CO2 m−2 s−1, respectively (sign convention: negative denotes fluxes from atmosphere to vegetation). The canopy was well coupled to the atmosphere, and there was rarely a significant build‐up of respiratory CO2 during the night. For observations in the wet season, the vegetation was a carbon dioxide sink, of maximal strength 0·15 mol m−2 d−1. However, it was a source of carbon dioxide for a brief period at the height of the dry season. Leaf carbon isotopic composition showed all the grasses except for one species to be C4, and all the palms and woody plants to be C3. The CO2 coming from the soil had an isotopic composition that suggested 40% of it was of C4 origin.

Control of Pecan Nut Casebearer and Fall Webworm in Pecans, 1996

Abstract Ten insecticides were evaluated for control of PNC and FW on pecans. Trials were conducted at a commercial pecan orchard located near Bristow, OK (Creek Co.). A section of the pecan orchard was divided into 11 blocks of trees, one being the untreated check and the remaining ten receiving one of the insecticidal treatments. Each block was about one acre in size. The trial used a mixture of native and cultivar pecan trees. Pretreatment PNC infestation levels were determined on 29 May. Twenty-five nut clusters on each of ten trees across blocks (250 nut clusters per treatment) were inspected for the presence of PNC eggs and damage. If an egg or damage was found on any nut within a cluster, it was considered infested. Treatments were applied on 1 and 2 Jun using an Ag-1, PTO driven, air blast sprayer calibrated to deliver 70 gpa. Only one application was made. Damage was evaluated on 26 Jun by inspecting 25 nut clusters/tree on 10 trees (250 nut clusters per treatment), at 5 to 8 feet above the ground for casebearer entries.

Economic opportunities for smallholders to combine pulpwood trees and food crops

Input/output data from tree growing experiments in Southeast Asia were analysed within the framework of a model of a smallholder farm. Data on cropping were obtained from surveys of farmers. Prior to formulating a whole farm model, this input/output data were modified in two ways: (a) a yield penalty was imposed upon a continuous cropping regime to reflect the impact of land degradation; (b) an agroforestry (intercropping) activity was synthesised by reference to an existing agroforestry bioeconomic model. The modelling framework was conventional linear programming. The interplay of land area availability, land and labour productivity, and interest rates lead to a relatively complex picture, even for the simplified farming systems that were examined. Model results showed a clear indication of the potential role of trees, but this potential role decreased with increasing interest rates. The analysis suggested that smaller farms will be less inclined towards tree growing. A mixture of trees and crops appears attractive, on purely economic grounds, over a wide range of interest rates and land areas. Consideration of factors outside the model, such as risk aversion objectives of smallholders, and their limited opportunities to borrow for investments in tree planting, reinforce the tendency to combine trees and crops.

Factors affecting the transfer of radiocaesium from soil to roe deer in forest ecosystems of southern Germany

Since 1987, in Southern Germany, as a consequence of the Chernobyl accident, the 137Cs activity concentration in roe deer (Capreolus capreolus) has been intensively monitored. A large data set is now available with approximately 5000 samples, with information about the location of the animal, the time of slaughtering, soil characteristics and distance to intensively managed agricultural land. Both the roe deer 137Cs activity concentrations and aggregated transfer coefficients soil-roe deer (Tag.r) show a considerable variability with geometric mean and geometric standard deviation in meat of 270·3.5±1 Bq·kg−1 and 0.01·3.5±1 m2·kg−1, respectively. From 1987 to 1991, Tag,r values exhibited a decline with an ecological half-life of about 3 years. Since 1991, no further decrease of the roe deer contamination level was observed. This general trend is superimposed by an increase in Tag,r in autumn that has occurred in almost every year, which is probably due to consumption of mushrooms. This hypothesis is supported by a significant positive correlation between the precipitation during July and August, stimulating the fungi's growth and the height of the maximum in Tag,r in autumn.Animals are less contaminated when living in parts of the forest from where they have access to intensively managed agricultural land. A small, but significant correlation is observed between the Tag,r and soil parameters; the total potassium content of the soil and the pH of the organic soil layer. The highest transfer coefficients soil-roe deer were found on a peat bog, where most values ranged from 0.01–0.1 m2·kg−1, and neither a pronounced seasonal variation, nor a long-term decrease was observed. On sites with coniferous forests, most Tag,r values range from 0.005 to 0.05 m2·kg−1, on sites with a mixture of coniferous and deciduous trees, the transfer coefficients range mostly from 0.002 to 0.02 m2·kg−1. This is a further indication of the importance of the uppermost soil layers and the biological processes therein with respect to the bioavailability of caesium. On the two sites, the values at the lower boundary are more typical for animals that have access to agricultural areas, whereas the higher values were observed in autumn and for animals grazing distant from agricultural areas.

The development of heathland in Orkney, Scotland: pollen records from Loch of Knitchen (Rousay) and Loch of Torness (Hoy)

Pollen records from two lake sites located in areas of modern heathland were used to reconstruct the local development of this vegetation type. A pollen record obtained from Loch of Knitchen on Rousay covered the last 6000 radiocarbon years. Betula-Corylus scrub was once locally present, although never a dominant community. Heath vegetation began to develop around 5700 BP. At about 5400 BP woodland taxa declined, possibly in response to Neolithic human activity, and heathland expanded. Calluna vulgaris increas ingly dominated the record thereafter, reflecting local blanket peat development. Data from Loch of Torness on Hoy cover the period from 7700 BP to around 4800 BP. Initial tall herb-type vegetation was replaced by a mixture of trees and heath taxa at around 7000 BP. Arboreal taxa declined at about 6000 BP, and the sub sequent record showed the development of maritime-type heath. The data show that heathland vegetation has been present in Orkney since at least 7000 BP, and that a range of causal processes have been important.

Control of Pecan Nut Casebearer in Pecans, 1995

Abstract Five insecticides were evaluated for control of PNC on pecans. Trials were conducted at a commercial pecan orchard located near Bristow, OK (Creek Co.). A section of the pecan orchard was divided into 6 blocks of trees, with each block receiving one of the treatments. Each block was ca. one acre in size. The trial used a mixture of native and cultivar pecan trees. Determination of pretreatment PNC infestation levels was done on 10 Jun. Twenty-five nut clusters, on each of four trees per block (100 nut clusters per treatment), were inspected for the presence of PNC eggs and damage. If an egg was found on any nut within a cluster, the cluster was considered infested. Treatments were applied on Jun 11-12 using an Ag-1, PTO driven, air-blast sprayer. The sprayer was calibrated to deliver 70 gpa. Only one application was made. Damage was evaluated on 29 Jun by inspecting 25 nut clusters/tree (100 nut clusters per treatment), at 5 to 8 feet above the ground for casebearer entries. A cluster was considered infested if one or more nuts within the cluster showed signs of larval entry.