Buffer Tree Research Articles

Buffer tree synthesis with consideration of temporal locality, sink polarity requirements, solution cost, congestion, and blockages

We give an overview of a buffer tree synthesis package which pays particular attention to the following issues: routing and buffer blockages, minimization of interconnect and buffer costs, congestion, exploitation of temporal locality among the sinks, and addressing sink polarity requirements. Experimental results demonstrate the effectiveness of the tool in comparison with previously proposed techniques.

Efficient Bulk Operations on Dynamic R-Trees

In recent years there has been an upsurge of interest in spatial databases. A major issue is how to manipulate efficiently massive amounts of spatial data stored on disk in multidimensional spatial indexes (data structures). Construction of spatial indexes (bulk loading ) has been studied intensively in the database community. The continuous arrival of massive amounts of new data makes it important to update existing indexes (bulk updating ) efficiently.In this paper we present a simple, yet efficient, technique for performing bulk update and query operations on multidimensional indexes. We present our technique in terms of the so-called R-tree and its variants, as they have emerged as practically efficient indexing methods for spatial data. Our method uses ideas from the buffer tree lazy buffering technique and fully utilizes the available internal memory and the page size of the operating system. We give a theoretical analysis of our technique, showing that it is efficient both in terms of I/ O communication, disk storage, and internal computation time. We also present the results of an extensive set of experiments showing that in practice our approach performs better than the previously best known bulk update methods with respect to update time, and that it produces a better quality index in terms of query performance. One important novel feature of our technique is that in most cases it allows us to perform a batch of updates and queries simultaneously. To be able to do so is essential in environments where queries have to be answered even while the index is being updated and reorganized.

Abatement of NO 3–N concentration in agricultural waters by narrow buffer strips

The performance of narrow buffer strips in abating the NO 3–N concentrations in the water coming from cropland was tested in an experiment carried out on the low plains of the Veneto Region (northeast Italy). The buffer was composed of a 5-m wide grass strip and a 1-m wide row of trees. Maize and wheat were cultivated in the neighbouring field during the monitoring period (December 1997–June 1999). Four experimental conditions were monitored, deriving from a combination of two levels of crop N fertilisation and two sizes of buffer trees. The narrow buffer was very effective in abating NO 3–N concentrations, allowing water to be discharged with a concentration always below 2 ppm. Its zone of influence might be bigger than its simple width. The abatement was also efficient during winter. Tree size showed no evident effect on the reduction of the concentration.

Retention of leaf litter in streams from riparian plantings in southern Ontario, Canada

This study examines the short-term leaf litter retention from three tree species used in rehabilitative streamside plantings at Washington Creek, southern Ontario, Canada. The number of leaves retained under different riparian conditions (wide tree buffer, meandering; narrow tree buffer, meandering; narrow tree buffer, channelized) differed significantly (P streambank > debris dams > roots > wood. Results from this study may aid in the design of riparian plantings within the scope of agroforestry systems.

Climatic Periodicity, Phenology, and Cambium Activity in Tropical Dry Forest Trees

The seasonal time course of vegetative phenology and cambium growth is compared for tree species from Central America and Asia growing in tropical climates with a long, severe dry season. Although the inhibition of plant growth by water stress is weH established, responses to seasonal drought vary widely among such trees, and their annual development is not weH synchronized by climatic seasonality. In deciduous trees growing at microsites with low soil moisture storage, phenology and cambium growth are weH correlated with each other and with seasonal rainfall, and most trees have distinct annual rings. Phenology and cambium growth are progressively uncoupled from climatic seasonality in brevideciduous and evergreen trees growing at microsites with large soil water reserves which buffer trees against seasonal drought and thus may prevent the formation of distinct annual rings. There is some experimental evidence conceming the control of growth initiation in apical meristems and the cambium, but little is known about the mechanisms which arrest growth and deterrnine qualitative changes in organ development and cambium cell differentiation.

European Red Mite and Twospotted Spider Mite Control on Apple, 1997

Abstract Six insecticide treatments were evaluated at the Plateau Experiment Station, Crossville, TN. The experimental design was randomized complete block with four replicates. Plots consisted of single trees separated by one buffer tree. Blocks were separated by a row of trees. All insecticide treatments were applied using a ‘Solo’ gasoline-powered back-pack sprayer providing 81.75 gal/A of finished spray on 25 July. Orthene, both formulations of Kelthane, and Omite were applied again on 5 Aug. Latron B-1956 was added to both Kelthane treatments at the rate of 4 oz/100 gallons spray. Forty leaves from each tree were sampled at random and put into a self-sealing plastic bag on 29 Jul, 4, 13 and 19 Aug. Ten leaves from each bag were sampled at random, and the number of mites/10 leaves was determined using a dissecting microscope. There were similar numbers of ERM and TSM on all treatments and collection dates. All data were subjected to ANOVA.

Effect of Experimental and Registered Miticides on Twospotted Spider Mite and European Red Mite, 1996

Abstract This experiment was conducted in a commercial orchard of mature ‘Delicious’ apples at Arrowhead Ranch, Bridgeport, WA. The plot was laid out in 2 rows, with buffer trees between treated trees in the row, and a buffer row between rows containing treatments. A pre-treatment count was made and replicates were assigned to blocks according to initial population and treatments were randomly assigned within replicates. The experimental design was a randomized complete block with 4 replicates. Treatments were applied 5 Jul 1996 with a handgun sprayer operated at about 300 psi. Twenty randomly selected leaves were collected from each replicate tree, and mites were removed from the leaves with a leaf-brushing machine. Mites were counted with the aid of a binocular microscope. A pretreatment sample and weekly post-treatment samples were taken.

Apple, Handgun Trials of New Insecticides Against Oblr, 1996

Abstract Treatments were applied with a truck-mounted, high pressure (450 psi), handgun sprayer dilute to run off to single apple tree plots in 2 orchards: ‘Idared’ trees (Brown orchard), which were about 15 years old, 13 ft high, and planted 19 X 27 ft apart, and ‘Rome’ trees (Nesbitt orchard), which were about 8 ft high and planted 11 X 18 ft apart. Treatments were arranged in a RCB design, separated by unsprayed buffer trees, and replicated twice in each orchard. All materials were applied on a 3-spray schedule, at 1st hatch (2 Jul), mid-hatch (16 Jul), and on 29 Jul. Check plots were not sprayed with insecticides during the test. Summer populations of larvae were compared by examining 20-50 growing terminals on each tree for live larvae on 9-11 Jul and again on 23-24 Jul. Fruit damage from the 1st summer generation of larvae was estimated initially on 1-2 Jul and again on 20-24 Aug by sampling up to 100 apples from each tree. At harvest (4 Oct for the ‘Rome’ applies in the Nesbit Orchard and 14-15 Oct for the ‘Idared’ applies in the Brown Orchard), up to 100 applies were sampled from each tree and OBLR damaged fruit was classified according to USDA grading standards into the categories of “Fancy”, #1, and culls.

Effect of Acaricides on Predatory Mites, 1996

Abstract This experiment was conducted in a mature ‘Fuji’ orchard in Pateros, WA, with undertree spinner-type sprinklers. A pre-treatment count was used to randomize the treatments among trees with similar mite populations. Three single-tree replicates per treatment were used. The treated trees had buffer trees separating them in the rows, and buffer rows separated rows containing treated trees. Treatments were applied with a handgun sprayer to the point of drip on 28 Aug, 1996. Mites were sampled by collecting 20 leaves/replicate, and were kept cool until counting. Mites were removed from the leaves with a leaf-brushing machine, and counted on the sticky surface of the glass plate with the aid of a stereoscopic microscope.

The Buffer Tree: A New Technique for Optimal I/O Algorithms

In this paper we develop a technique for transforming an internal-memory tree data structure into an external-memory structure. We show how the technique can be used to develop a search tree like structure, a priority queue, a (one-dimensional) range tree and a segment tree, and give examples of how these structures can be used to develop efficient I/O algorithms. All our algorithms are either extremely simple or straightforward generalizations of known internal-memory algorithms - given the developed external data structures. We believe that algorithms relying on the developed structure will be of practical interest due to relatively small constants in the asymptotic bounds.

Efficacy of Provado and Thiodan for Aphid Control, 1995

Abstract The trial was conducted in a 2-acre 5-yr-old mixed ‘Delicious’, ‘Gala‘, and ‘Idared’ orchard with under-tree irrigation. Guthion 50W (2 lb form./acre) was applied for codling moth control on 2 and 16 Jun, 7 Jul, and 1 and 22 Aug with an air blast sprayer. The experimental design was a RCB with 5 single-tree replicates per treatment. There were two or more buffer trees within rows between treated trees. Dilute sprays were applied to runoff with a handgun sprayer operated at 150-200 psi. Per acre rates were based on application of 1 gal of spray per tree or 182 gal/acre. Aphids (alate + apterous) were counted in situ on the three most recently fully expanded leaves (minimum of 1 inch in length and edges completely unfolded) on three terminals per tree. Pre-treatment counts were made on 20 Jun. All aphicide treatments were applied on 21 Jun, except one follow-up Thiodan application on 10 Jul (19 DAT). Post-treatment counts were made 5, 12, 19, 26, and 34 DAT.

Effect of Spinosad, Neemix and Agri-Mek on Second Generation Western Tentiform Leafminer, 1995

Abstract The test was conducted in a 4-yr-old ‘Fuji’ orchard in Milton-Freewater, OR. Trees were sprayed to the point of drip with a handgun sprayer operated at ca. 250 psi. There were buffer rows between each row containing treated trees, and at least one buffer tree between any two treatment trees within a row. Treatments were timed for three points in the phenological development of leafminers: 1st sapfeeder (1st SF), applied 20 Jun; 10% tissue feeder (TF), the current standard timing, applied 26 Jun; and 1st pupae, applied 4 Jul. Phenological samples (dissection of mines to determine the percentage in each stage) were taken twice weekly to determine the correct timing for pesticide applications. Population samples were taken ca. weekly.

Apple, European Red Mite and Twospotted Spider Mite Control, 1995

Abstract Six treatments were evaluated at the Plateau Experiment Station, Crossville. The experimental design was RCB with four replicates. Plots consisted of single trees separated by one buffer tree. Blocks were separated by a row of trees. Insecticide treatments were applied using a ‘Solo’ gasoline powered sprayer providing 81.75 gpa of finished spray on 1 and 25 Aug. Latron B-1956 was added to all treatments at the rate of 4 oz/100 gal spray. Forty leaves from each tree were sampled at random and put in a plastic zip-lock bag on 7, 15, 22, 29 Aug and 5 Sep. Ten leaves from each bag were taken at random, and the number of mites per leaf was counted using a dissecting microscope. All data were subjected to ANOVA.

Effect of Registered and Experimental Aphicides on Aphis Pomi, 1995

Abstract This experiment was conducted in a first leaf commercial ‘Scartlet’ orchard on M.7 rootstock near Malaga, WA. Plots consisted of single trees, with buffer trees between trees. Two shoots per tree were tagged, and all counts were taken from tagged shoots. The aphid population on the shoot was assessed by counting individual aphids on the most infested leaf on the shoot. Pre-treatment counts were used as a blocking factor for randomization. Treatments were applied with a handgun to the point of drip on 25 Jul. Post-treatment counts were taken ca. weekly until late Aug.

Apple, Obliquebanded Leafroller Control with Spinosad, 1995

Abstract This study was conducted in a 16-yr-old orchard of ‘Rhode Island Greening‘ trees which measured 12 ft wide and 10-16 ft high and were planted 20 by 20 ft. The treatments were replicated 4 times as single-tree plots and arranged in a randomized block design, with each plot surrounded by 4 unsprayed buffer trees. Treatments were applied with a FMC DO 10 handgun sprayer operated at 150 psi. Approximately 3.6 gal of spray solution was applied to each tree as a spray to drip treatment. Treatments were applied at approximately 10, 50 and 90% egg hatch of OBLR 29 Jun, 10 and 24 Jul, respectively. Application of treatments were arranged in 3 different spray schedules: A, 29 Jun and 10 Jul; B, 10 Jul and 24 Jul; and C, 29 Jun, 10 Jul and 24 Jul. Spinosad was compared to a standard commercial treatment, Lorsban 50W (170 g AI per 100 gal applied on schedule C) and an untreated check. On 16 Aug, 100 terminals per plot were assessed for feeding damage caused by the summer generation of OBLR larvae. On 22 Aug, 100 fruit were collected from each plot and assessed for damage caused by larvae. The Spinosad treatments were analyzed separately as a factorial experiment to compare main effects of rate and schedule.

Efficacy of the Aphicides M-Pede, Align and Thiodan, 1994

Abstract This experiment was conducted in a 2-yr-old commercial nonbearing orchard near East Wenatchee, WA. Plots consisted of groups of four trees across in four rows. There were four to five buffer trees within rows between plots. One shoot per tree was tagged, and all counts were taken from tagged shoots. Pre-treatment counts of the number of aphids on the most infested leaf were used as a blocking factor for randomization. Treatments were applied with a handgun to the point of drip on 18 Aug. Posttreatment counts were taken ca. weekly until late Sep, when counts dropped to zero.

Test of Registered and Experimental Insecticides for Aphid Control, 1994

Abstract This experiment was conducted in a 2-yr-old commercial ‘Gala’ orchard near Orondo, WA. Trees were planted in double rows. Plots consisted of groups of contiguous trees within a double row, with buffer trees between plots, and buffer rows between treated rows. Four trees per plot with aphid infestations were chosen, and one shoot per tree was tagged. The number of aphids on the most infested leaf was counted on tagged shoots. Pre-treatmerit counts were used as a blocking factor for randomization. Treatments were applied with a handgun to the point of drip on 15 Jul. Post-treatment counts were taken ca. weekly until late Aug.

Apple, Acaricides Test, 1994

Abstract Treatments were applied with a truck-mounted, high pressure (450 psi) handgun sprayer dilute to singletree plots of ‘Empire’ apples that were 10.5 ft high and planted 14 by 21 ft apart. Treatments were in a RCB design, replicated three times. Plots were separated by an unsprayed buffer tree. This test was designed to compare the effectiveness of acaricides against high summer mite populations. The first spray was applied on 18 Jul, when mite populations in the orchard exceeded recommended threshold levels of 5.0 mites per leaf. All plots were retreated on 28 Jul. ERM were counted on 25 randomly selected intermediate-aged fruit cluster or spur leaves in the laboratory using a dissecting microscope at zero, three and seven days after the first treatment. After the second spray, mites were counted on 25 randomly selected leaves/tree at weekly intervals. Mites were removed from leaves of samples after the second spray with a Henderson-McBurnie mite brushing machine.

Apple, Airblast Evaluation of Insecticides, 1993

Abstract Experimental sprays were applied to 3 tree plots in a randomized block design consisting of 2 replicates of ‘Yorking’ and 2 replicates of ‘Golden Delicious’ with a buffer tree between plots and a buffer row between blocks. These trees were spaced 20 × 30 ft apart and were 19 years old. Experimental sprays were applied with a Friend Airmaster ‘309’ calibrated to deliver 100 gpa at 2.0 mph. Application dates and materials varied between treatments and are listed in the table for WALH. All applications were complete sprays. A routine schedule of fungicides (Dithane 75DF, Nova 40WP, captan 50WP and Benlate 50DF) was maintained throughout the experiment. Effectiveness on SA was evaluated by counting aphid-infested leaves/10 top terminals, and aphids/most infested leaf. The effect of the sprays on WALH was evaluated by counting nymphs/25 injured leaves/tree. Effectiveness of test chemicals on ERM and ZM was evaluated by counting these mites several times during the season on samples of 25 random leaves/tree, 100 leaves/treatment. The effect of sprays on S. punctum was evaluated by 3-min counts of adults and larvae around the periphery of the test trees. STLM were evaluated by a 5-min count of mines around the periphery of the trees at the end of each of the first two generations before peak emergence of adults. OFM shoot injury was assessed by making a 3 min observation around the periphery of each tree and counting injured shoots. Internal feeding lepidoptera were evaluated with a 5-min count of apples exuding frass and the total number of apples evaluated to give percent injured apples. Effectiveness of chemicals on fruit feeders was assessed for injury by scoring drop apples on 6 and 21 Jul and 3 and 16 Aug and picked samples of 50, 100 and 100 fruit per replication on 16 Aug, 3 and 20 Sep, respectively. Pest pressure was extremely high throughout the season. Fruits were rated as 0 (no russet), 1 (raised lenticels), 2 (1-10% russeted surface), 3 (11-25% russeted surface), 4 (26-50% russeted surface), or 5 (>51% russeted surface). Possible ranges are 0-30 (none to raised lenticels) 31-60 (raised lenticels to 1- 10% russeted surface), 61-90 (1-10% to 11-25% russeted surface, 91-120 (11-25% to 26-50% russeted surface), and 121-150 (26-50% to >51% russeted surface). Effects on parasitoids attacking CM and OFM were evaluated several times during the season on a single tree within each plot by picking up to 20 apples exuding frass in a 10-min count and rearing the larvae in the laboratory on a semi-synthetic lima bean diet at 20 °C, 16:8 D:L. Injured apples were collected on 7 and 22 Jun, 7 and 19 Jul, 4 and 18 Aug, and 2 Sept. Larvae of CM and OFM were transferred singly to diet cups on each collection date and monitored several times a week for adult moth and parasitoid emergence for 5 weeks. Two species of braconid parasitoids were found during these evaluations, Macrocentrus delicatus which was by far the most common and Charmon extensor. Rates of parasitism for each treatment were calculated by dividing the total number of parasitoids by the total number of parasitoids plus total number of CM and OFM adults.

Citrus Rust Mite Control with Bas 300 111 on Texas Citrus, 1993

Abstract Experimental BAS 300 1II, alone and tank mixed with either Lorsban or Supracide, was compared to Vendex for efficacy against CRM. Treatments were randomized and replicated 4 times on single tree plots in a 7-yr-old grapefruit orchard on 15 × 24 ft spacing. Each sprayed tree was separated on all sides by unsprayed buffer trees. Treatment sprays were applied on 10 May to foliar runoff with a Hypro 5200 high pressure handgun sprayer operating at 200 psi. At each count date, 12 fruit per replicate were randomly selected and examined for CRM in situ with a 10X handlens. All live CRM were counted in two, 1-sq cm lens fields on the shaded side of each fruit. The two counts per fruit were averaged and recorded as one observation.