Increase In Trunk Diameter Research Articles

Real-time tree physiology monitoring system

Electronic devices have been developed to operate in real time with an alarm on the streets of Diptychs. The devices are IoT-platforms based on the ESP-32 microprocessor, equipped with a LoRa transceiver to transmit data to a module that collects tree data and sends it to the cloud using GSM/GPRS. Pilot implementation will take place in 2023 on the territory of the Botanical Garden of Petrozavodsk State University (Republic of Karelia, Russia). The work was carried out with the aim of studying the seasonal dynamics of Malus domestica under growing conditions in the extreme territories of Northern Russia. The research results show that on May 16-18, during the characteristic phenological phase «The beginning of reddening of leaves» (ВВСН 11) at an average daily air temperature of +5.7°C, a sum of temperatures of 487°C and an average daily temperature of 325°C. The phenophase «Beginning of flowering» (ВВСН 61) was noted on May 28 at an air temperature of +13.3 °C. The phenophase «Beginning of fruit ripening» (ВВСН 81-86) was noted on August 16. The beginning of the increase in trunk diameter, according to the distant number, was noted on June 15-20, the growth lasted until July 20-25 and amounted to about 3 mm. The research results showed that the species Malus Domestica may be preferable for introduction into the culture of northern fruit growing.

РОСТ ПОЛУСИБСОВЫХ ПОТОМСТВ СОСНЫ ОБЫКНОВЕННОЙ В ИСПЫТАТЕЛЬНЫХ КУЛЬТУРАХ СЕВЕРНОГО КАЗАХСТАНА

The article discusses the main taxation indicators of half-sibs at the age of 36 years. The total viability of all families is 51.5%, the average height is 17.04 ± 0.13 m, and average trunk diameter at a height of 1.3 m is 19.97 ± 0.21 cm. A high negative correlation (r = -0.68) was found with respect to the trunk diameter and viability indicators. It was found that the height growth of half-sibs is influenced by genotype by 30.6%, and the diameter growth - by 15.6%. A significant increase in height compared to the control was observed in 40.7% of families, while a minor increase in trunk diameter was noted in a small portion of families - 5.6%. The selective height improvement effect amounted to 8.8%, and for trunk diameter, it was 13.5%. It was determined that the offspring of plus trees obtained in the same year with free pollination in a natural plantation and a collection plot (clone of a plus tree) had both low and high overall combining ability, depending on the pollinator. Based on the results obtained, it is concluded that it is impractical to separate families from the same plus tree depending on the origin when assessing their growth.

Features of Growth Processes of Sweet Cherry Trees of Various Ripening Terms in the Conditions of the Right-Bank Forest-Steppe of Ukraine

One of the main requirements of the new stone fruit varieties recommended for commercial cultivation is a compact crown shape that allows for greater plant density and easier crown maintenance. The aim of the research was to establish the growth processes of the above-ground parts of cherry trees in varieties of different ripening periods. The article presents the results of studies of the features of apical and lateral growth of sweet cherry trees. Biological and varietal features of tree growth strength, growth and total length of annual shoots are determined. The dependence of tree trunk growth on apical growth force is established. According to the results of research, sweet cherry varieties are grouped according to the strength of growth: the vigorous varieties are Amazonka, Dar Mliyeva, Zoryana, Mliyivska zhovta; the semi dwarf are Aboryhenka, Alyonushka, Drohana zhovta, Mirazh; the dwarfing are Biryuza, Donetskyy uholyok, Melitopolska krapchasta, Meotida. The smallest increase in trunk diameter was found for the dwarfing variety Biryuza, and the largest – for the variety Drohana zhovta. The highest yield load per unit cross-sectional area of the trunk was recorded for the variety Donetskyy uholyok, the lowest – for Drohana zhovta. The amount of growth in the trunk diameter was inversely dependent on a load of trees with the crop and the strength of apical growth of sweet cherry trees. The features of shoot-forming ability allow characterising the shape of the crown of cherry trees: round – Donetskyy uholyok, Amazonka; high-round – varieties of Aborigenka, Dar Mliyeva, Zoryana; wide-pyramidal – Alyonushka, Drohana zhovta, Melitopolska krap-chasta; pyramidal – Mliyivska zhovta, Mirazh; low – Meotida, Biryuza. Dar Mliyeva, Zoryana, Mirazh, Melitopolska krapchasta and Drohana zhovta varieties have high shootability; the Mliyivska zhovta, Aboryhenka, Meotida, Amazonka varieties have medium shootability; Alyonushka, Biryuza, Donetskyy uholyok varieties have low shootability

Phosphonate Treatment Effects on Phytophthora Root Rot Control, Phosphite Residues and Phytophthora cactorum Inoculum in Young Apple Orchards.

Phytophthora root rot, caused by Phytophthora cactorum, is an economically important disease on young apple trees. Limited information is available on the effect of different phosphonate application methods and dosages on disease control, fruit and root phosphite concentrations, and soil and root pathogen inoculum levels. Evaluation of phosphonate treatments in three apple orchard trials (two in the Grabouw and one in the Koue Bokkeveld region) showed that foliar sprays (ammonium or potassium phosphonate), trunk sprays and trunk paints, were equally effective at increasing trunk diameter in one trial and yield in a second trial over a 25-month period. Foliar ammonium and potassium phosphonate sprays (12 g of phosphorous acid/tree), and two different dosages of the ammonium phosphonate sprays (∼4.8 g or 12 g of phosphorous acid/tree) were all equally effective at improving tree growth. The addition of a bark penetrant (polyether-polymethylsiloxane-copolymer) to trunk sprays did not improve the activity of trunk sprays. The low dosage ammonium phosphonate foliar spray (∼4.8 g a.i./tree) was the only treatment that, in general, yielded significantly lower root phosphite concentrations than the other phosphonate treatments. Root phosphite concentrations were significantly positively correlated (P < 0.0001) with an increase in trunk diameter and negatively (P < 0.0001) with P. cactorum root DNA quantities. Phosphite fruit residues were <31 ppm for all treatments, with the trunk paint treatment (80 g of phosphorous acid/tree applied annually) yielding significantly lower residues than the higher dosage foliar sprays (∼12 g a.i./tree). Twenty-one months posttreatment, most of the phosphonate treatments in all of the trials similarly significantly reduced P. cactorum DNA quantities estimated directly from roots, but not from soil based on soil baiting DNA analysis. Pathogen quantities in fine feeder roots did not differ significantly from those in higher-order roots (<5 mm diameter). P. cactorum DNA quantities estimated using DNA quantification directly from roots were significantly correlated (P < 0.0001) with those obtained through root leaf baiting DNA analysis and, to a lesser extent, with soil leaf baiting DNA quantities (P = 0.025).

Growth features of Arbutus andrachne L. under the conditions of field vegetation experiment on the Southern Coast of the Crimea

The dependence of the growth rate of Arbutus andrachne L. on some environmental factors was studied under the conditions of the Southern Coast vegetation experiment in different periods of the species vegetation, which made it possible to find the optimal and limiting conditions for its growth. In March, vegetation began at an average daily air temperature of 3.5 – 7.50 °C and the increase in stem diameter was approximately 0.42 % (0.09 mm), at the second stage (April-May) – 3.7 % (0.58 mm) with a further exit to plateau. In July - August, two sections of the d % change are observed: the first section is from July 27 till August 19 - intensive growth of d % by 12.58 % (1.961 mm), the second section after August 19 – access to the growth plateau, which is associated with an increase in air temperature to 30-35 °C. In September-October, two sections of the d % change are observed: the first section lasted from September 01 till September 15 - intensive growth of d % by 3.55 % (0.582 mm), the second section after September 15 – exit to a plateau of growth, lowering the air temperature to 8-10 °C and the end of the growing season. In November, an increase in trunk diameter was not observed. The optimal environmental factors were: in March-May, Ta = 20-2 °C, Da = 0.4-1.2 kPa, I = 300-900 mmol / m2s; July-August, Ta = 22-28 °C, Da = 1.4-2.5 kPa, I = 500-1000 μmol / m2s; in September-October, Ta = 16-25 °C, Da = 0.3-1.5 kPa, I = 400-800 μmol / m2s, respectively. The results of our experiments allow us to compare the ecological and physiological characteristics we obtained with the climatic conditions of a particular region and evaluate the possibilities of introducing it into other regions.

The growth characteristics of Juniperus excelsa M. Bieb. in the greenhouse conditions of the Southern coast of the Crimea

The dependence of the growth intensity of Juniperus excelsa M. Bieb on some environmental factors in the greenhouse conditions of the Southern Coast of the Crimea was studied. Vegetation and trunk diameter growth (d,%) started after March 15. There are two growth peaks: the first growth peak (15.03.–27.07.) led to an increase in d,% by 7.12% (0.053% per day) – with a slowdown in growth (28.04 –27.05) and (13.07 – 25.07) associated with a decrease in air temperature. The second – (12.09 – 18.11) led to an increase in d,% by 5.06% (0.075% per day), while also slowing growth at this time (05.11.–14.11.) was observed. After the second phase of active growth (14.11), there is an access to the growth plateau with the resumption of the growing season only in March next year. During the studied vegetation period (2019), the increase in trunk diameter d,% was 12.18% or 1.89 mm. Optimal conditions of maxima and boundaries of optimal regions for the first growth peak: d%=f(I,Ta) – Ta=22–28°C, I=500–800 mkmol/m2s, for d,%=f(I,Da) – Da=1.8–2.3 kPa, I=500–800 mkmol/m2s. For the second growth peak: d%=f(I,Ta) – Ta=22–26°C, I=400–750 mkmol/m2s, for d,%=f(I, Da) – Da =0.3–1.2 kPa, I=400–750 mkmol/m2s.

Enhanced Degradation of TCE on a Superfund Site Using Endophyte-Assisted Poplar Tree Phytoremediation.

Trichloroethylene (TCE) is a widespread environmental pollutant common in groundwater plumes associated with industrial manufacturing areas. We had previously isolated and characterized a natural bacterial endophyte, Enterobacter sp. strain PDN3, of poplar trees, that rapidly metabolizes TCE, releasing chloride ion. We now report findings from a successful three-year field trial of endophyte-assisted phytoremediation on the Middlefield-Ellis-Whisman Superfund Study Area TCE plume in the Silicon Valley of California. The inoculated poplar trees exhibited increased growth and reduced TCE phytotoxic effects with a 32% increase in trunk diameter compared to mock-inoculated control poplar trees. The inoculated trees excreted 50% more chloride ion into the rhizosphere, indicative of increased TCE metabolism in planta. Data from tree core analysis of the tree tissues provided further supporting evidence of the enhanced rate of degradation of the chlorinated solvents in the inoculated trees. Test well groundwater analyses demonstrated a marked decrease in concentration of TCE and its derivatives from the tree-associated groundwater plume. The concentration of TCE decreased from 300 μg/L upstream of the planted area to less than 5 μg/L downstream of the planted area. TCE derivatives were similarly removed with cis-1,2-dichloroethene decreasing from 160 μg/L to less than 5 μg/L and trans-1,2-dichloroethene decreasing from 3.1 μg/L to less than 0.5 μg/L downstream of the planted trees. 1,1-dichloroethene and vinyl chloride both decreased from 6.8 and 0.77 μg/L, respectively, to below the reporting limit of 0.5 μg/L providing strong evidence of the ability of the endophytic inoculated trees to effectively remove TCE from affected groundwater. The combination of native pollutant-degrading endophytic bacteria and fast-growing poplar tree systems offers a readily deployable, cost-effective approach for the degradation of TCE, and may help mitigate potential transfer up the food chain, volatilization to the atmosphere, as well as direct phytotoxic impacts to plants used in this type of phytoremediation.

Phenology and growth responses of Fraser fir (Abies fraseri) Christmas trees along an elevational gradient, southern Appalachian Mountains, USA

Fraser fir (Abies fraseri) trees are endemic to locations above 1500m in the southern Appalachian Mountains, and are also grown commercially for Christmas trees well below their native range (down to 600m). To evaluate how phenology and growth of this species will respond to climate drivers associated with warming, we assessed the timing of bud-burst, shoot growth, trunk growth, as well as shoot- and leaf-level architecture, of Fraser fir Christmas trees along an elevational gradient from 664 to 1228m. Daytime maximum temperatures and evaporative demand were highest at low elevation and cloud events and higher wind speeds occurred more often at high elevations. Bud-burst occurred 6days sooner, new shoots ceased elongation 10days sooner, and radial trunk growth ended 8days later at low elevations than at high elevations, indicating a shift and lengthening of the growing season. Final shoot length did not vary among elevations, but the percent increase in trunk diameter was greatest at middle elevations. Architectural characteristics such as specific needle mass, needle packing density, and silhouette-to-projected area ratios generally did not vary with elevation. As climate change progresses, higher cloud ceilings, increased evaporative demand, and higher temperatures may further shift the timing of the growing season and reduce growth at low elevation Christmas tree farms, but farms at higher elevations may benefit from a longer growing season.

Біологічні особливості деяких представників родини Рутових в умовах Ботанічного саду ДНУ

Питання адаптивного садівництва особливо актуальні в Україні, де фактори зовнішнього середовища обмежують різноманітність вирощуваних культур і стабільність їх плодоношення. Метою дослідження було вивчення біологічних особливостей росту і плодоношення цитрусових, а також відбір перспективних сортів грейпфрута (Citrus paradisi Marf.), апельсина (Citrus cіnensis Osb), лимона (Citrus limon L.), кінкана (Fortunella Swingle), мандарина (Citrus reticulata Blanco), придатних для вирощування в оранжереї Ботанічного саду ДНУ, за природного освітлення. Основні експериментальні роботи проведені в 2015-2016 році в умовах оранжереї Дніпропетровського ботанічного саду. Всі обліки і спостереження проводилися відповідно до вимог методики дослідної справи. Фенологічні спостереження проводили за всіма видами та сортами. Спостереження проводили протягом вегетації через день. З’ясовано терміни і тривалість проходження основних фенологічних фаз рослин із родини Рутових (Rutaceae Juss.) . Досліджено вплив температурного режиму на ростові показники представників даної родини. Встановлено, що ці процеси цілком залежать від видового і сортового складу. В залежності від прогрівання повітря та ґрунту в оранжереї, початок росту пагонів починається значно раніше, ніж фіксувалося різними дослідниками у природних умовах, проте постійне зниження температур уночі призводить до затримки розвитку рослин.

Impact of Nursery Root Pruning and Tree Orientation at Planting on Growth and Anchorage

Root pruning by shaving 12 L container root balls when shifting to 51 L containers did not impact Acer rubrum L. or Quercus virginiana Mill. root architecture within the top 12 cm of planted 51 L root balls five years later, despite marked differences at planting, and had no impact on tree height or trunk diameter increase. Root pruning in the nursery did not affect bending stress required to tilt Acer trunks up to five degrees (anchorage) either one, two, or three years after landscape planting. In contrast, anchorage was greater the second year after planting Quercus that were root pruned. Rotating trees 180 degrees at planting from their orientation in the nursery had no impact on Acer or Quercus anchorage, tree height, or trunk diameter. Rotating oak (not maple) trees 180 degrees at planting increased root cross-sectional area growing from the hot (south) side of the root ball when trees were rotated at planting.

Responses of several soil and plant indicators to post-harvest regulated deficit irrigation in olive trees and their potential for irrigation scheduling

The response of olive trees to deficit irrigation during post-harvest has been little evaluated because low rainfall often precludes the need to irrigate at this phenological stage in the Mediterranean Basin where olive is mostly cultivated. In many growing areas of Argentina, the lower latitude and continental climate leads to harvesting table olives in mid-summer when evapotranspiration is still high and rainfall is low. We assessed the responses of soil moisture and several plant-based indicators to post-harvest regulated deficit irrigation (RDI) in two growing seasons in order to: 1) determine the responses of the indicators to a range of irrigation levels; 2) elucidate the relationships between the different soil and plant variables; and 3) evaluate the appropriateness of the indicators for scheduling irrigation. Three RDI treatments (66, 33, 0% crop evapotranspiration; ETc) and a control (100% ETc) were applied for 75days from mid-summer to mid-fall in a cv. ‘Manzanilla fina’ orchard during 2009 and 2010. The treatments received irrigation equivalent to the control during the rest of the season. Soil relative extractable water (REW%), midday stem water potential (Ψs), leaf conductance (gl), sap flow, and trunk diameter variations were the variables evaluated. The RDI treatments generated a wide range of REW values (0–125%) with all of the plant indicators being affected to some degree. Midday stem water potential increased linearly with REW until it reached a break point at 48% REW, above which Ψs maintained a plateau at −1.75MPa. The increase in maximum trunk diameter (MXTD) showed strong relationships with REW, Ψs, and gl. Trunk growth rate (TGR) showed a very early response to water-withholding in both seasons, and trunk growth decreased along with Ψs until it reached a constant negative growth rate of −12μmd−1at a Ψs of −2.7MPa. Trunk maximum daily shrinkage was much less responsive to irrigation than either MXTD or TGR. Our results during post-harvest RDI in an arid region suggest that automated soil moisture sensors can be used to schedule irrigation at different water stress levels if reliable soil moisture values can be measured, and indicate that a continuous recording of trunk diameter has sufficient enough potential for irrigation scheduling that further investigation of MXTD and TGR is warranted.

Grafting mature unproductive black walnut trees to improved cultivars demonstrates horticultural and economic feasibility in Missouri, USA

Black walnut (Juglans nigra) is a specialty nut crop produced in the central USA. Most nuts are harvested from unimproved wild trees and are of poor quality; however, a growing number of nuts are coming from grafted orchards with superior quality. Our objective was to study the feasibility of converting mature unimproved black walnut trees to improved cultivars by grafting or top-working. A 20-year-old black walnut planting in southwest Missouri was used. 108 trees were divided into blocks and randomly designated as ungrafted, or grafted to one of three cultivars ('Sparrow', 'Kwik-Krop', 'Emma K') in May 2009. Fungicide treatments applied to rootstock trunks were also studied. Initial grafting success was 94%. Seven grafted trees had broken or died within five years leaving an overall success rate of 81%. By 2014, scion height averaged 5.5 m with mean girth 13.2 cm. As expected, increase in trunk diameter at breast height (137 cm) was greater in ungrafted trees (27.1%) compared with grafted trees (21.8%). Also as expected, nut production was reduced among grafted trees during the healing process; ungrafted trees yielded a cumulative average of 298 nuts tree-1 over five years, whereas grafted trees yielded 28 nuts. At the common market price of US $ 0.22 kg-1 for unimproved black walnuts, that represents an economic loss of only $ 88 over five years from 54 grafted trees. While top-working established black walnut trees is labor intensive, and may result in loss of some trees, the process is horticulturally feasible and the economic trade-off appears justifiable.

Conventional Citrus of Some Scion/Rootstock Combinations Show Field Tolerance under High Huanglongbing Disease Pressure

The citrus disease huanglongbing (HLB) has become endemic in Florida, with estimates that greater than 80% of citrus trees are currently infected. Although there are no commercial citrus varieties with strong HLB resistance, some field tolerance has been observed in trees exposed to the disease after they were mature. There is great urgency to identify citrus which may permit economic citrus production where HLB is endemic. Therefore, the objective of this study was to assess field tolerance to HLB. To expedite the trial due to urgency, nursery trees were purchased on rootstock varieties as available. The trial included the following unbalanced scion/rootstock combinations: ‘Hamlin/Kinkoji’, ‘Hamlin/Cleopatra’, ‘Temple/Cleopatra’, ‘Fallglo/Kinkoji’, ‘Sugar Belle/Sour Orange’, ‘Tango/Kuharske’, and ‘Ruby Red/Kinkoji’, with most comparisons based solely on scion/rootstock combinations. A randomized complete block experiment was established at Fort Pierce, FL, in Sept. 2010. All trees exhibited symptoms of HLB and tested positive for the Candidatus Liberibacter asiaticus (CLas) bacterium by Oct. 2012, with similar titers [directly assessed as cycle threshold (Ct) using quantitative polymerase chain reaction (qPCR)] measured for all scion/rootstocks at most sample dates, but early titer development in ‘Ruby Red/Kinkoji’ was significantly lower than several other scion/rootstocks. Across all time-points, ‘Fallglo/Kinkoji’ had the lowest rating of distinctive HLB mottling and ‘Ruby Red/Kinkoji’ had the highest rating, but ‘SugarBelle/Sour Orange’ had the highest percentage of leaves affected. After 5 years, ‘SugarBelle/Sour Orange’ and ‘Tango/Kuharske’ had the greatest overall increase in trunk diameter, and were among the healthiest in overall appearance. In Oct. 2015, ‘SugarBelle/Sour Orange’ and ‘Tango/Kuharske’ trees had significantly greater fruit load (80–88 fruit/tree) followed by ‘Temple/Cleopatra’ and ‘Fallglo/Kinkoji’ (31–35 fruit/tree) while ‘Hamlin/Kinkoji’, ‘Hamlin/Cleopatra’, and ‘Ruby Red/Kinkoji’ produced less than 20 fruit per tree. Despite becoming infected by CLas in less than 2 years after planting, the trees continued to grow and all scion/rootstocks displayed increasing fruit production, although very low in ‘Hamlin/Kinkoji’, ‘Hamlin/Cleopatra’, and ‘Ruby Red/Kinkoji’. Growth and fruit production in the highest performing scion/rootstocks were likely less than would be expected for healthy trees, but these results are promising, with markedly better response of some scion/rootstocks with mandarin hybrid scions compared with trees with sweet orange or grapefruit scions. Larger fully replicated trials are underway. It is noteworthy that the most pronounced HLB symptoms and higher early pathogen titer, which are the two criteria most widely used in assessing HLB resistance, were not associated with the lowest growth and cropping, and focus on early symptomatic traits when screening for resistance may obscure important disease tolerance.

An Image-based Method to Study the Fruit Tree Canopy and the Pruning Biomass Production in a Peach Orchard

The feasibility of two nondestructive methods based on image processing techniques was assessed for fruit tree research. The methods were evaluated in a 2-year (2011 and 2012) field experiment, during which various irrigation and soil management treatments were set up in a commercial peach orchard. Canopy image analysis was conducted using two approaches, namely the orthoimage and the lateral image technique. The proposed methods were compared with other classical measurements such as trunk diameter (TD) increase and pruning weight (PW). Orthoimage canopy area (OCA) analysis resulted in a reliable and sensitive technique to study the active crop growth along the growing season. The OCA values obtained were highly correlated with TD measurements (r2 = 0.88), thus describing an exponential significant model (y = 0.0997 e0.0521x). Cumulative crop growth was determined using the virtual pruning (VP) technique. VP estimates were well correlated with fruit tree PWs during 2011 (r2 = 0.86) and 2012 (r2 = 0.80). The nondestructive image-based techniques proved sensitive to crop growth and useful for the study of fruit tree canopies. On the basis of our results, we conclude that the proposed image analysis methods are valuable new approaches with wide applications in fruit tree research.

Physiological Studies on Apricot Trees Fertilization Grown in Ismailia Governorate 2-effect of Mineral (npk), Organic (compost) Fertilizers and Some Soil bio-stimulants on Growth and Nutritional Status of "Canino" Apricot Trees

THE EFFECT of mineral (NPK) soil application either alone or in … combination with organic (compost) and some soil bio-stimulants (EM, bio-fertilizer, humic acid and compost tea) on increment percentage in trunk diameter (ITD %), average length and thickness of new shoots (cm), average number of leaves per shoot, leaf area and its dry weight, leaf photosynthetic pigments and leaf mineral content of apricot "Canino" cv. budded on local apricot rootstock grown at El-Kassasien Horti. Res. Sta., Ismailia Governorate during two successive seasons of (2010&2011) and (2011&2012). The obtained results revealed that all vegetative growth parameters under study except organic fertilizer (compost) at 100 % level resulted in significant increase in trunk diameter (ITD %), average length and thickness of new shoots (cm), average number of leaves per shoot and leaf area and its dry weight during both seasons of study. The same treatments increased, also, leaf nutrient contents of N, P, K, Ca, Mg, Zn, Fe and Mn as well as leaf photosynthetic pigments (chlorophyll a, b and carotein). It could be concluded that all investigated NPK soil application in mineral form, organic (compost) fertilizers and some soil stimulants results in significant effect, however, the fertilization with mineral (NPK) at 100% level (T1) and mineral NPK in mineral form at 50% level + organic (compost) fertilizer at 50% level coupled with all tested soil stimulants (T13) were the most effective treatments for increasing vegetative growth parameters and leaf nutrient contents of "Canino" cv. Apricot trees.

Effect of Biochar Amendments on Peach Replant Disease

The use of biochar as a soil amendment has generated interest all over the world, and it has been advocated as a means to improve soil fertility and sequester carbon. The objective of this study was to test if the use of pinewood biochar could reduce the detrimental effects of replant disease (RD) on peach tree growth and biomass production. An RD-susceptible peach rootstock, Lovell, was grown in soil from a peach replant site (control), sterilized soil (sterilized), and biochar-amended soil at 10% and 20% (v/v) [low biochar (LB) and high biochar (HB), respectively], all from the same site. Trunk diameter increase was measured weekly; total aboveground and belowground biomass was determined by harvesting a subsample of plants at 11, 22, and 33 weeks after planting. Soil samples, and foliar and root tissue samples were collected before each harvesting date and analyzed for nutrient content. Total aboveground and belowground biomass production was significantly higher in the biochar and sterilized soil treatment (S) compared with the control. Root carbon (C*) content was significantly greater in the HB treatment compared with the control. Soil nitrate-N was significantly greater in the HB treatment by the third harvesting date, and foliar magnesium (Mg) concentrations were significantly higher in both biochar treatments for all harvesting dates. The results from this study provide evidence that biochar may alleviate RD in peach trees.

Pruning Severity and Crown Position Influence Aspect Ratio Change

Growth on one branch is suppressed in proportion to pruning severity, resulting in a predictable reduction in branch:trunk diameter (aspect) ratio. However, little is known about response to pruning multiple branches. Several of the largest branches on live oak (15.3 cm trunk diameter) were pruned with four severities (0%, 25%, 50%, and 75%), then branch, nearby stem, and trunk diameter were measured for five subsequent years. Rate of trunk diameter increase five years after pruning was greatest for trees pruned with the 25% severity. Aspect ratio on all three pruned and measured branches decreased with time after pruning, pruning severity, and increasing height in the crown. Mean aspect ratio ceased declining between three and five years after pruning. The decrease in aspect ratio over time and with increasing severity on pruned branches was less pronounced in the lower crown than in the upper crown. Smaller change in aspect ratio on pruned branches in the lower crown suggests that when structurally pruning trees, branches in the lower crown may require a higher pruning severity to effect the same change in aspect ratio as upper branches.

EVALUATION OF KRYMSK®5 (VSL-2) AND KRYMSK®6 (LC-52) AS ROOTSTOCKS FOR SWEET CHERRY 'KORDIA'

During a 6-year period the growth and production of trees of sweet cherry ‘Kordia’ grafted on rootstocks Krymsk®5 (VSL-2), Krymsk®6 (LC-52) and GiSelA 5 were compared. Shoot growth, increase in trunk diameter and intensity of flowering of ‘Kordia’ were almost similar on all three stocks. Fruit production per tree was significantly higher for ‘Kordia’ on rootstocks Krymsk®6 and GiSelA 5, while that on Krymsk®5 was similar to that on GiSelA 5. Both Krymsk rootstocks gave a small reduction in fruit size, and a slightly lower sugar and acid content. With Krymsk®6, smaller fruit size was related to the higher fruit load of the trees and may be avoided by thinning the tree to the optimum crop load. With Krymsk®5, the reduction in fruit size could not be attributed to overcropping. Fruit cracking, a big problem for cherry growers in areas with high risks of rain in the harvest period, occurred less on Krymsk®6 than on GiSelA 5 or Krymsk®5. Both Krymsk rootstocks produced significantly more root suckers than GiSelA 5. The highest numbers were observed for Krymsk®5, which produced on average 3.3 suckers per tree per during the first 6 years in the orchard. Krymsk®5 also developed burrknots. From this trial it is concluded that Krymsk®6 can be a good alternative rootstock to GiSelA 5, especially for less well drained soils and because its effect on reducing the occurrence of fruit cracking. However, because of its tendency to reduce fruit size, overcropping should be prevented. Therefore, Krymsk®6 is probably less suited for self-compatible cultivars than for cultivars setting fruit only after cross pollination.

MULCH APPLICATION IN HOPS, GRAPES AND OLIVES

To assess the effect of a range of organic mulch materials in perennial crops, trials were established in ‘Super Pride’ hop fields (both organic and conventional), a new planting of ‘Gewurztraminer’ wine grapes (organically grown), and a one year old olive grove. Hops: compost produced from hop waste was applied as a surface mulch to 4 vine plots at the rate of 70 t/ha in a newly established organic field and a wellestablished field at a conventional site. Mulched plots were compared with control plots in a randomised complete block design with 5 replicates per treatment. Mulch treatments had no effect on vine height. There were no significant differences between the mulched and control plots in hop percentage dry matter, percentage alpha acid, beta acid, or coltumulene, or ratio of acids. Soil bulk density was lower in the mulched plots in both systems. Mulch treatments showed higher available potassium, organic carbon and microbial biomass C. Grapes: three grades of mulch were compared with an untreated control. Mulch materials were a mature compost (AS4454) mulch composed of eucalypt bark, chicken manure, paper pulp and grape marc; a composted mulch of eucalypt bark mixed with chicken manure; and a non-composted mulch consisting of eucalypt bark. Mulches were applied to a depth of 20 cm along the vine row. Trial design was a randomised complete block with 9 vines per treatment. The increase in trunk diameter was highest in the mature compost mulch plots, as was the pruning weight after 12 months. Non-composted mulch plots showed the highest levels of organic carbon, while the composted mulch plots had the greatest number of earthworms. Both mature and composted mulch plots showed higher levels of available phosphorous and potassium than non-composted mulch or control plots. Olives: composted bark mulch was compared with an untreated control in a new olive grove planted directly into pasture. Mulch was applied to a depth of 10 cm around the base of each tree, covering a radius of 20 cm from the trunk, with 7 single tree plots per treatment. Tree growth was 35% higher in the mulched plots. There was no effect on soil bulk density, moisture, pH or EC. Soil temperature was higher in the mulched plots.

Effect of Transplanting Date and Harvest Method on Growth and Survival of Three Urban Tree Species in an Arid Climate

The major challenges for transplanting trees in arid regions compared to temperate regions are higher mortality and slower rate of establishment. As such, date and method of transplanting can potentially improve survival and establishment as well as subsequent landscape performance of transplanted trees in arid climate. In the present study, three urban species commonly used in the Isfahan, Iran, landscape including eldarica pine (Pinus eldarica Medw.), white mulberry (Morus alba L.), and smoothleaf elm (Ulmus carpinifolia Gled.), were transplanted from January to June 2010, when mean air temperature was less than 10°C (early winter), between 10°C and 20°C (early spring), or more than 20°C (late spring). Half of the trees were bare root (BR) and half balled and burlapped (B&amp;B). White mulberry and smoothleaf elm trees transplanted early in winter had the highest survival percentage over two years. The best survival for eldarica pine was observed in early spring transplanted trees. For all species, survival rate and trunk diameter increase of B&amp;B trees were significantly greater than BR trees during the first year. Also, the first year’s shoot growth and shoot number of pine trees, and dieback on elm trees, were significantly affected by transplanting method. During the second year, tree growth and survival for all species were similar for B&amp;B and BR trees. Annual shoot growth of eldarica pine and smoothleaf elm trees, but not white mulberry, equaled to nontransplanted trees by the end of third year after transplanting, suggesting a species-specific response for post-transplant establishment in arid climate.