Hedge Pruning Research Articles

Summer Hedge Pruning of Pecan in the Southeastern United States

Hedge pruning has been used in southeastern US pecan (Carya illinoinensis) orchards for ∼10 to 15 years and has become common in the region within the past 5 years. However, questions remain regarding how pecan trees in the southeastern United States will respond to hedge pruning into the hot summer months in a humid environment. Two treatments were evaluated for ‘Creek’ and ‘Caddo’ pecan: dormant hedge-pruned (Jan–Feb 2019 and 2022) and summer hedge-pruned (Jun 2019 and 2020). Summer hedge pruning did not affect pecan yield, nut weight, or percent kernel compared with dormant-season pruning. Length of shoot regrowth was reduced significantly by summer hedge pruning compared with dormant-season hedge pruning. The advantages of hedge pruning ‘Creek’ and ‘Caddo’ from the dormant season through midsummer can help transition southeastern US pecan production to a more profitable and sustainable system.

Canopy hedge pruning in pecan production differentially affects groups of arthropod pests and associated natural enemies

Controlling canopy growth and size through pruning techniques in perennial agroecosystems is often crucial to maximizing productivity. However, the implications of modifying canopy architecture for arthropod management are often overlooked. We studied the effects of hedge pruning on pests and natural enemies on mature pecan trees by assessing the abundance of: 1) leaf-dwelling aphids and mites, 2) visually detectable injuries caused by black pecan aphids [Melanocallis caryaefoliae (Davis)] and Phylloxera spp., 3) aphid parasitoids and parasitized hosts (aphid mummies), and 4) predatory mites. Additionally, we assessed the prevalence of entomopathogens that dwell on the orchard floor, under the trees. Hedge pruning decreased Phylloxera infestation but increased pressure from scorch mites and the yellow aphid complex. Black pecan aphid abundance responded inconsistently, but their damage was consistently reduced in hedged canopies. Predatory mites were only affected by hedging in the second year when higher populations were observed. Although parasitoid wasp abundance was not affected by hedging, more parasitized aphids (mummies) were observed in trees that did not receive pruning in the first year. Also, higher activity of entomopathogens was observed in soil cores collected under hedged trees in the first year but lower in the second. Taken together, the effects of hedge pruning pecan canopies were case-specific, and cannot be generalized across pests or natural enemies. Nevertheless, structural and environmental variation across seasons and within hedge pruning systems clearly have implications for crop protection in pecans and other perennial systems.

ANALYSIS OF THE EFFECTS OF WORKING POSITION ON MUSCLE FATIGUE DURING HEDGE PRUNING: A CROSS-SECTIONAL STUDY BASED ON CHINESE GARDEN WORKERS

Occupational health is still in the developmental stage in China. There is a lack of focus on garden workers. Hedge pruning is one of garden workers’ main tasks, a common operation form in modern landscaping. Garden workers who operate the hedge trimmer generally suffer from work-related musculoskeletal disorders (WMSDs). This study aims to demonstrate which working condition causes the most muscle fatigue, evaluate work fatigue accurately, and reduce WMSDs in garden workers. One hundred and twenty garden workers were studied during six hedge pruning conditions using surface electromyography (sEMG) and a motion capture system. The sEMG of the erector spinae, trapezius, biceps brachii and brachioradialis muscle, and kinematic parameters was measured during the operation. The average standardized sEMG values of upper-limb and trunk muscles in different working conditions were analyzed using single-factor analysis of variance. In the six working conditions, the trunk inclination angle was the largest (40–50∘) in horizontal pruning of short hedges, and the load of erector spinae (39.31–39.62%) was the highest in this condition. Operators’ arms were above shoulder height in high hedge pruning, the shoulder joint angle and the elbow joint angle were generally larger, the load of trapezius (49.33–55.65%), biceps brachii (46.50–52.35%) and right brachioradialis (52.35%) was the highest in horizontal pruning of high hedges, and the load of left brachioradialis (40.91%) was the highest in vertical pruning of high hedges. Awkward working postures can lead to problems such as overwork of upper-limb and trunk muscles, representing a risk that increases occupational illness, injuries and chronic diseases among garden workers. Preventive measures are required to reduce the occurrence of excessive local muscle load, and prevent the occurrence of occupational diseases.

Hedge and central pruning in a high-density pecan orchard in southern Brazil

This study aimed at evaluating the influence of two pruning methods, as well as absence of pruning, on vegetative and productive development and in the quality of pecan fruits in a high-density orchard. The experiment was conducted with the cultivar Melhorada in a commercial pecan orchard in municipality of Santa Rosa, Rio Grande do Sul (RS), Brazil. The study was carried out between July 2018 and June 2020. In a randomized block design, the following treatments were applied: no pruning, hedge pruning and central pruning. Hedge pruning increased limb growth, while central pruning decreased the number of dry branches. Fruit production oscillated in the cycles. In the first, production was higher when central pruning was conducted. In the second cycle, it was higher in unpruned trees. Even though both pruning methods decreased the number of fruit with closed epicarps, they did not affect most variables of fruit quality. Therefore, results show that pruning methods promote vegetative development of pecan trees, reducing dry branches, but they are inconclusive regarding their production and have no significant effect on the main variables of their fruit quality. The evaluation and continuity of pruning for more cycles is important to obtain the most consistent results for indicating the best alternative for producers.

Fertilization and pruning improve vegetative growth and architecture of tropical lowland Borneo Prima Mandarin citrus

Vegetative growth of citrus can be increased through a combination of fertilization and pruning. Borneo Prima Mandarin (Citrus reticulata cv Borneo Prima) is a superior local commodity that is grown in lowlands. It has an interesting orange skin, while normally the tropical lowland citrus has a green skin colour. As a new commodity, Borneo Prima Mandarin has to be developed in order to increase production and improve quality. There is no specific cultural practices, so it needs to be developed, especially on fertilizing and pruning. The first experiment aims to observe the plant growth and architecture of plants grown in the orchard. The first factor was the nitrogen fertilization rate (0, 20, 40, 60 g N per tree per application) and the second was pruning (without pruning, open center pruning, hedge pruning). In the second experiment, the plants were applied with the same factors of experiment 1, but were grown on a root observation chamber sized 40 x 20 x 60 cm (length x width x height) which aims to observe the shoot root’s growth and the plant’s biomass. Nitrogen fertilizer had a significant effect to the growth of the Borneo Prima Mandarin, i.e number of shoots and leaves. Twenty grams of nitrogen fertilizer per aplication was efficient to produce new shoots and leaves. Pruning treatments had significant effects towards the plant architecture (i.e reducing plant height, canopy shade projection and canopy length). Open center pruning and hedge pruning made the crown more open which increased the light interception. The shoot grew rapidly two weeks after fertilizing and also pruning. While the root grew rapidly after shoot dormancy.

Mechanical pruning and soil organic amendments in vineyards of Syrah: effects on grape composition

Aim: The interaction of mechanized pruning systems and soil organic amendment can increase vine productivity. However, since the increase in productivity may affect grape composition, this study aimed to understand the effects of the interaction between these two practices.Methods and materials: Two field trials were implemented in Shiraz vineyards in two different wine regions. Mechanical hedge pruning was compared with hand spur pruning and four different organic amendments were tested: biochar, municipal solid waste compost, cattle manure and sewage sludge.Results: Mechanical pruning reduced the total soluble solids (TSS) and pH of the grapes, but had no effects on the other variables. Organic amendments also reduced TSS, especially sewage sludge, and tended to reduce total anthocyanins and total phenols. The effect of the interaction between both factors on grape composition was never significant. A negative relationship between yield and TSS was observed, while titratable acidity had no relationship with yield. Total anthocyanins were also negatively related to yield. A positive relation between TSS and total anthocyanins was also observed.Conclusions: The results show that the combination of mechanical pruning and soil organic amendment is a powerful tool for increasing productivity, but it has some effects on grape composition.Significance and impact of study: The reduction in some fruit composition variables showed that, while mechanical pruning does not significantly affect grape composition, the choice of type and amount of organic amendment will depend on the destination of the grapes.

Mechanical pruning and soil organic amendments in vineyards of ‘Syrah’: effects on wine mineral composition

The interaction of mechanized pruning systems and soil organic amendment can affect vine vegetative and reproductive growth. However, since organic amendments supply several mineral elements, namely heavy metals, this study aimed to understand the effects of the interaction between these two practices on the mineral composition of wine. Two field trials were implemented in ‘Syrah’ vineyards in two Portuguese wine regions (Lisboa and Tejo). Mechanical hedge pruning was compared with hand spur pruning and four different organic amendments were tested: biochar, municipal solid waste compost, cattle manure and sewage sludge. The nitrogen (N), phosphorus (P) and potassium (K) wine contents were significantly reduced by mechanical pruning while calcium (Ca) and magnesium (Mg) contents were tendentially higher in this pruning system. Mechanical pruning also reduced the content of some minor elements, such as arsenic (As), molybdenum (Mo) and nickel (Ni). In 2014, the year with the higher reproductive growth, some other elements also decreased as a consequence of the mechanical pruning (gallium - Ga; lithium – Li; rubidium - Rb, thallium – Tl; yttrium - Y). Concerning the organic amendments, sewage sludge was associated with the wines with the lowest P and iron (Fe) content. Ca content was tendentially higher in municipal solid waste compost and sewage sludge treatments. Mechanical pruning and organic amendments had different effects on the mineral composition of wine, according to each specific element. However, the legal limits, recommended by OIV and established by European Union, as well as the technical limits, adopted by winemakers, were never exceeded and the interaction of both practices does not seem to be a problem in what concerns to the mineral composition of the produced wines.

Jojoba pruning: New practices to rejuvenate the plant, improve yield and reduce alternate bearing

Commercial pruning practice in jojoba plantations is traditionally dictated by maintenance requirements only. It enables machine movement between the plants and efficient harvest but is not designed to maximize long-term productivity. In this study, mechanical and manual pruning approaches were tested in two cultivars in a mature jojoba plantation, in comparison to the common practice. These new approaches were designed to enable better light penetration into the canopy, aiming to improve growth and productivity. As jojoba is an alternate bearing crop, the vegetative and reproductive performances were observed over four years, by remote sensing and manual measurements. The pruning type and strategy had a significant effect on growth, with a distinction between the two tested cultivars. Top-pruning methods were found to best encourage new branching and yield, while side-pruning practices were less effective. Several treatments, including hedge pruning, attenuated or eliminated the alternation cycle. We conclude that using the proposed pruning practices would be beneficial in jojoba cultivation, and that the specific method should be suited to the cultivar characteristics.

Mechanical Pruning and Soil Fertilization with Distinct Organic Amendments in Vineyards of Syrah: Effects on Vegetative and Reproductive Growth

The effects of fully mechanized pruning systems on physiology, vigor and yield of grapevines have been studied for more than forty years and are an interesting way to reduce production costs. Organic amending of vineyard soil is a way to increase vine productivity. Thus, this study aims to understand the effects of the interaction between these two practices, on vine growth and productivity. Two trial fields were implemented on Shiraz vineyards in 2 different wine regions. Mechanical hedge pruning was compared with hand spur pruning and four different organic amendments were tested: biochar; municipal solid waste compost; cattle manure; sewage sludge. Mechanical pruning and organic amendments, by themselves, did not significantly increase yield. However, the interaction between both factors reduced the impact of self-regulation mechanisms (budburst, bud fruitfulness and cluster weight) in mechanical pruning and successfully increased yield, without decreasing vegetative growth. The effects of mechanical pruning with the application of organic amendments to soil on yield is significant and, thereby, the choice of the organic amendment and its amount, must be done considering the destiny of produced grapes.

Responses of shoot growth, return flowering, and fruit yield to post-pruning practices and growth regulator application in olive trees

Winter mechanical hedge pruning of olive trees can result in a strong post-pruning shoot growth response and a low return flowering intensity the following year. However, post-pruning practices including tip heading, watersprout thinning, and the application of the growth inhibitor mepiquat chloride (MC) may positively reduce subsequent vegetative growth and promote flowering. Two experiments were carried out with the aim of addressing the following questions: (1) Do these post-pruning practices applied on trees that received simulated mechanical pruning during the winter reduce growth and increase flowering in the spring of the following year?; and (2) What is the optimal MC dose in unpruned trees needed to increase flowering the following spring? In the first experiment, five-year-old olive trees (cv. Arbequina) growing in a fairly low density orchard (208 trees ha−1) were hedge pruned at the end of winter using manual clippers on the east and west sides to simulate mechanical disk pruning, and the post-pruning treatments were applied at the pit hardening stage (early summer). In the second experiment, foliar or soil application of MC was performed at pit hardening in unpruned trees. The results show that tip heading of new shoots led to a large number of lateral shoots that flowered little, or not at all, the following spring. In contrast, the watersprout thinning treatment had sufficient flowering to significantly increase fruit number and yield the following year compared to tip heading. Foliar application of MC (1500 ppm) after winter pruning did not inhibit new shoot growth, return flowering was low, and yield was less than the watersprout thinning treatment. The lack of a post-pruning response to foliar MC was likely related to the dose used (1500 ppm). In the second experiment, a foliar application of MC at 3000 ppm was associated with greater return flowering and yield than an untreated control. In conclusion, thinning of vigorous watersprouts at the pit hardening stage three months after simulated winter mechanical hedge pruning can improve fruit number and yield the next year, especially on a per canopy volume basis. Furthermore, the responses to foliar MC application in unpruned trees suggest that more detailed post-pruning studies with MC application doses in the 2000–3000 ppm range and at additional phenological stages should be performed over several consecutive years to assess whether this practice could be a suitable management tool.

Effect of summer hedge-pruning and gibberellic acid foliar spray on yield and alternate bearing of S-700 jojoba clone (Simmondsia chinensis (Link) Schneider)

In jojoba, flower buds develop exclusively on new growth near branch tips. An increase in the number of growing tips (branching frequency) could possibly increase flower buds and seed yield. This study was conducted to determine the effect of summer hedge pruning and gibberellic acid spraying on vegetative growth, flower bud production, seed yield and alternate bearing of 12-year-old S-700 jojoba clone. Hedge-pruning was done after harvesting during the mid- July in 2015 and 2016 seasons. Trees crown formed as hedge wall of about 1.0 m, 1.5 m width, and unpruned trees as control. Trees were sprayed with GA3 at 0, 100 and 150 ppm three times a year started at 1st August with one-month intervals. Obtained results showed that hedge-pruning treatments alone or in combination with GA3 foliar spray treatments enhanced branching density, flower bud production, seed yield and, controlling alternate bearing. Hedge- pruning at 1.5 m width in combination with GA3 at 150 ppm proved to be the most effective treatment for improving seed and wax yield of S-700 jojoba clone in the off-year season.

Impact of simulated mechanical hedge pruning and wood age on new shoot demography and return flowering in olive trees

More vigorous watersprouts and fewer low vigor shoots form as wood age increases at the cutting points with greater canopy pruning depth in olive trees, which reduces return flowering. Such information is relevant to long-term olive orchard pruning strategies in hedgerows. Demographic analysis of growth responses to pruning in fruit trees seeks the quantification of the typology of new shoots originating from the remaining branches. Pruning of hedgerows using mechanical discs is becoming increasingly common in orchards, but little information is available as to how such pruning, which does not discriminate between branch size, wood age at the cutting point, branch type, or position, modifies subsequent new shoot demography. Hence, the experiment described in this study in young olive trees (cv. Arbequina) assessed the following questions: (1) Is the type and growth of new shoots associated with the intensity of mechanical pruning and/or the wood age on which they grow? (2) How many growing seasons does it take for new shoots formed after pruning to flower? The principal hypothesis was that a greater proportion of vigorous watersprouts form compared to low vigor shoots as wood age at the cutting points increases with canopy pruning depth, and that the watersprouts have low flowering potential. Both new shoot growth and return flowering were monitored on exposed supporting wood over several growing seasons after implementing three winter (25W, 50W, and 75W) pruning levels of increasing intensity and one summer pruning (75S) treatment along with an unpruned control (CON). As hypothesized, a greater number and elongation of vigorous watersprouts were found as wood age increased at the cutting points with greater winter pruning intensity, and the watersprouts had low levels of return flowering even 3 full years after pruning compared to the CON. Growth of low vigor shoots was relatively more important than watersprout growth in the severe summer pruning treatment, although 3 years after the summer pruning flowering was not fully recovered. In contrast, the more lightly pruned winter treatments (25W, 50W) did not show significant differences in flowering with the CON at the end of 3 years. Thus, mechanical hedge pruning in olive trees should be light-to-moderate to avoid the formation of watersprouts on older wood, which leads to long-term reductions in flowering.

Mechanical Hedge Pruning Affects Nut Size, Nut Quality, Wind Damage, and Stem Water Potential of Pecan in Humid Conditions

Recent extensive pecan [Carya illinoinensis (Wangenh.) K. Koch] plantings coincided with a shift toward the planting of pecan trees at higher density by Georgia pecan producers in anticipation of maintaining these densities through hedge pruning. Initial studies of mechanical hedge pruning in the low-light environment of the southeastern United States have failed to show significant benefits to pecan production. The objectives of this study were to compare the effects of hedge pruning on pecan nut quality, yield, and midday stem water potential (ψ) of pecan trees in the temperate climate of the southeastern United States and to evaluate the effect of hedge pruning on windstorm damage to pecan trees. Treatments were arranged in a randomized complete block design with three blocks. Two treatments were evaluated; 1) Hedge-pruned; 2) Nonhedge-pruned (control). Midday stem ψ was 8.5%, 17.6%, and 16.6% higher (P ≤ 0.05), indicating less water stress, on hedged trees than on nonhedged trees during 2015, 2016, and 2017, respectively. Nut weight and percent kernel were increased (P ≤ 0.05) by hedge pruning 2 of 3 years of the study. Although no direct positive effect of hedge pruning on in-shell nut yield was observed, hedge pruning was not detrimental to pecan yield in the short term. Hurricane/Tropical Storm Irma brought damaging winds to the entire pecan-producing region of Georgia on 11 Sept. 2017, resulting in blown down trees, broken branches, and immature nuts blown from the trees. Hedged trees had 60% less wind damage in the form of major limb breakage and tree loss than did nonhedged trees.

Pertumbuhan dan Keragaan Tanaman Jeruk Keprok Borneo Prima pada Dosis Pupuk dan Bentuk Pangkas Berbeda

Borneo Prima Mandarin (Citrus reticulata cv Borneo Prima) is a new local commodity that grown in lowland but has an interesting orange skin. As a new commodity, Borneo Prima Mandarin has to be developed in order to reduce citrus import. The research was conducted in lowland area (250 m above sea level) IPB research station, Sindang Barang, Bogor from February 2014 to February 2015. The aim of this research was to observe the effect of phosphorus and potassium (PK) fertilizer and pruning on the growth and performance of the plants. This research used Randomize Complete Block Design (RCBD) with two factors. The first factor was aplication of PK fertilizer (15 g P+ 10 g K, 15 g P+ 15 g K, 20 g P+10 g K, 20 g P+15 g K per plant) and the second factor was pruning form (without pruning, open center pruning and hedge pruning). The result showed that the combination of phosporus and potassium fertilizer just gave a significant effect to number of shoot. The highest number of new shoots formed by fertilizing 15 g P+10 g K per tree per application. Pruning treatments had significant effect to plant architecture (i.e reduce plant height, land occupation). Open center pruning and hedge pruning made the crown more open that can increase the light interception so that increase the rate of photosynthesis.

Mechanical Hedge Pruning of Pecan in a Relatively Low-light Environment

Long-term productivity of commercial pecan [Carya illinoinensis (Wangenh.) K. Koch] enterprises in relatively low-light environments such as the southeastern United States are limited by excessive tree crowding as orchards age. An effective horticultural strategy for countering this problem in relatively high-light environments is mechanical hedge-type pruning; however, uncertainty persists regarding the best strategies in low-light environments. This report describes the results of a 4-year study regarding the response of ≈25-year-old ‘Desirable’ pecan trees to different mechanical hedgerow-type, moderate canopy width (i.e., 2.43-m cuts from tree axis) pruning strategies. Canopy treatments were nonpruned control (NPC), annual dormant season side-hedge pruning on two faces, annual summer season side-hedge pruning on two faces, and alternating annual dormant season side-hedge pruning on a single alternating face. Relative to the NPC treatment, all three pruning strategies: 1) reduced in-shell nut yields by roughly 19% to 38%; 2) reduced marketable nut-meat yield by ≈19% to 36%; 3) failed to stimulate shoot development or fruiting within the central interior zone of tree canopies; 4) increased kernel percentage of nuts; 5) increased nut-meat grade; 6) substantially reduced alternate bearing intensity (I = 0.51 to ≈0.20); and 7) reduced orchard crowding. Pruning-associated reductions in nut yield appear sufficient to limit the commercial usefulness of annual or biennial mechanical hedgerow-type pruning of ‘Desirable’ pecan orchards at moderate canopy widths in relatively low-light environments such as the southeastern United States.

One-Time Pruning of Pecan Trees Induced Limited and Short-Term Benefits in Canopy Light Penetration, Yield, and Nut Quality

Twenty-five-year-old `Cape Fear', `Desirable', and `Kiowa' pecan [Carya illinoinensis (Wangenh.) C. Koch] trees were either not pruned, or subjected to single selective or mechanical pruning using a mechanical hedger [or hedge pruning (HP)] in the dormant season 2003. Canopy light interception, yield, and nut quality were monitored during a period of three years. Leaf area index and light interception were significantly affected during the first growing season after treatment application, but after three years canopies grew back to control levels. In general, there were small positive effects observed on yield and nut quality after pruning. Minor improvements were recorded for `Desirable', in which yield was affected positively by both pruning strategies in 2004. However, most effects disappeared by the third year. `Desirable' responded better than `Cape Fear', whereas no beneficial effects were recorded on `Kiowa'. In 2005, yield was significantly reduced in HP trees of `Cape Fear' and `Kiowa'. Alternate bearing index was unaffected by pruning treatment or cultivar. Kernel percentage increased only in HP `Desirable' trees in 2003 and 2004. Kernel quality was improved in HP `Cape Fear' and `Desirable' in the first growing season after treatment application, but not in 2004. In 2005, quality was again improved in HP `Desirable'. The results of the current study indicate that one-time pruning of pecan trees induce positive short-term effect on light, but not necessarily an increase in productivity and nut quality.

Hedge Pruning Pecan

An ever increasing cost:price squeeze on the profitability of pecan (Carya illinoinensis) farming is driving a search for alternate husbandry approaches. `Wichita' and `Western' trees maintained at relatively high tree population density, by mechanized hedge pruning and topping, produced greater nut yield than an orchard treatment in which tree population density was reduced by tree thinning (144% for `Wichita' and 113% for `Western Schley'). Evaluation of three different hedge pruning strategies, over a 20-year period, identified a discrete canopy hedge pruning and topping strategy using a 2-year cycle, as being superior to that of a discrete canopy hedge pruning and topping strategy using an 8-year cycle, but not as good as a continuous canopy hedge pruning and topping strategy using a 1-year cycle. An evaluation of 21 commercial cultivars indicated that nut yields of essentially all cultivars can be relatively high if properly hedge pruned [annual in-shell nut yields of 2200 to 3626 lb/acre (2465.8 to 4064.1 kg·ha-1), depending on cultivar]. Comparative alternate bearing intensity and nut quality characteristics are reported for 21 cultivars. These evaluations indicate that pecan orchards can be highly productive, with substantially reduced alternate bearing, when managed via a hedge-row-like pruning strategy giving narrow canopies [3403 lb/acre (3814.2 kg·ha-1) for `Wichita' and 3472 lb/acre (3891.5 kg·ha-1) for `Western Schley']. North-south-oriented (N-S) hedgerows produced higher yields that did east-west (E-W) hedgerows (yield for N-S `Wichita' was 158% that of E-W trees and N-S `Western Schley' was 174% that of E-W trees).These data indicate that mechanized hedge pruning and topping offers an attractive alternative to the conventional husbandry paradigm.

Economic Evaluation of Mechanized Pruning of Coffee in Hawaii

Marketable coffee (Coffea arabica) yield and cost of production under two systems of mechanized pruning—hedging and stumping— were investigated. Data were collected from 1997 to 2001—a single pruning cycle—on three cultivars on three farms on Kauai, Maui, and Molokai. Treatments were variations of hedging and stumping, including time of pruning, methods of re-growth control, and tree in-row spacing were applied to each coffee cultivar. Economic evaluation was based on a partial budget analysis of the actual costs per year of the different pruning systems used on each farm. Mechanical pruning costs per acre for best hedging and stumping treatments across cultivars were 90% and 83% less, respectively, than the current practice of manual pruning. Response to pruning system varied according to coffee cultivar, tree in-row spacing and farm location. The tall cultivar Mokka had higher yields when hedged at 5 ft (1.5 m) tall and 5 ft wide, and the semi-dwarf cultivar Yellow Catuai had higher yields when stumped at 2 ft (0.6 m) tall. Hedge pruning should be done early in the year, January to February, for the semi-dwarfs, `Yellow Catuai' and `Red Catuai', but can be delayed until May for `Mokka'. Annual topping in the hedging systems should be done January to May for `Yellow Catuai' but maybe delayed until May for `Mokka' and `Red Catuai' without yield loss. The economic evaluation revealed that the cost of stumping was higher than hedging. For `Yellow Catuai' on Kauai the economic evaluation indicated that although the cost of stumping was higher, the accompanying higher yields resulted in a higher gross margin for this system. When stumping, verti- cal branches can be set with a contact herbicide spray to avoid higher hand pruning costs without lowering yields. Stumps should be narrowed after stumping if spaced, 2.5 ft (0.75 m) the current standard in-row spacing for mechanical harvesting. Wide in-row spacing (5 ft) should be considered by growers when planting or re-planting.

Characterization of the Pecan Industry in North America with Emphasis in the Southwest

The pecan is native to North America and is cultured as a major crop in both the United States and Mexico. In the early part of this century, pecans were thought of as a secondary crop grown in the southern geographic section of the United States. Increased demand for use as a nutritious food has resulted in expansion of the industry into the desert Southwest and California. Adaptive cultivars and irrigation coupled with the lack of diseases and insects has been instrumental in industry development in the West. As the industry has matured during the latter part of the century, pecan culture has improved into a strong crop enterprise business. Orchard management technique and orchard development concepts have been refined, resulting in increased production and awareness. In recent years, production in Mexico has impacted the U.S. price structure and pecan industry economy. The alternate-bearing nature of pecans also impacts prices received by growers. The aging of pecan trees has resulted in serious dilemmas, such as increased tree size and shading. This situation requires techniques such as tree thinning or hedge pruning to enhance annual production and improve nut quality. Various ramifications and parameters of these management practices will be discussed.

EFFECT OF HEDGEROW ORIENTATION ON MAIZE LIGHT INTERCEPTION AND YIELD IN BLACK LOCUST ALLEYS

SUMMARY An experiment was carried out in Ohio, USA, to verify whether north-south hedgerow orientation, and hence location of maize rows on the western or eastern sides within the alleys, would influence maize light interception and yield at higher latitudes. Compared to unpruned black locust hedges, pruning improved light availability to maize at ear height by 36%, and allowed 52% more light to penetrate to the 15 cm height of the maize plants. Maize plants on the second row from the unpruned hedges received more light than the first maize row, but this was reversed with hedge pruning, especially of light reaching the 15 cm height of the maize plants. The location of maize rows on the western or eastern sides within the north-south aligned alleys did not have a significant effect on photosynthetically active radiation available to the various maize rows in the alleys, neither on the ultimate grain yield and yield components. What is important is to prune the hedges when they have grown tall enough, not w...