Trees Ha-1 Research Articles

Nutrient accumulation in Eucalyptus bark at different population densities

ABSTRACT The objective of this study was to quantify the accumulation of nutrients in the bark of four eucalyptus clones at 12 years-of-age, planted at different population densities, and the values were extrapolated to kg of nutrients per hectare. The experiment used randomized blocks in a 4 × 3 factorial design and three replications, with four Eucalyptus clones (2486, I182, I144, and GG100) planted at three population densities (416, 833, and 1111 trees ha-1). The rigorous cubage of three trees per plot was performed by collecting discs of bark at the following heights: diameter at breast height (1.30 m), 0, 25, 50, 75, and 100% of the commercial height of the stem. The bark discs of each tree were grouped and used to determine N, P, K, Ca, Mg, and S content, in addition to the basic density. The volume and dry mass of bark per tree was estimated and the accumulation of nutrients per tree ha-1 was estimated sequentially, for each population density. Analysis of variance and Tukey’s post-hoc tests verified that Ca showed the greatest accumulation in the bark, followed by N, K, S, Mg, and P. The increase in population density contributed to higher bark production and greater nutrient accumulation per hectare. However, this increase was not evident when comparing densities of 833 and 1111 trees ha-1.

The effects of alternative training and planting systems on light relations in mango (Mangifera indica) orchards in Far North Queensland

Part of a project to transform subtropical/tropical tree productivity in Queensland is a study of light relations in mango (Mangifera indica) orchards in Far North Queensland. A study of the baseline relationship between light interception, canopy volume and yield in ‘Kensington Pride’ trees found that as canopy volume increased, light interception reached a maximum between 61 and 68%. The relationship between light interception and tree yield (t ha-1) varied over two years highlighting the biennial bearing habit of mango. An associated ongoing study is looking at the effects on light interception, canopy volume and yield for three mango cultivars, resulting from various planting density and tree training systems. The planting systems being studied include three planting densities: low density (208 trees ha-1, 8×6 m), medium density (450 tree ha-1, 6×4 m) and high density (1250 trees ha-1, 4×2 m) and two training systems (conventional and single leader) in three commercial mango cultivars (‘Keitt, CalypsoTM’ and ‘NMBP 1243’). The first year’s results have indicated that density and cultivar had significant effects on light interception in 1.5-year-old trees. ‘Keitt’ canopies had higher light interception than ‘CalypsoTM’ or ‘NMBP1243’, while high density plantings intercepted significantly more light. Training system also increased light interception from 1.38% in the low-density conventional planting to 9.5% in the single leader, high-density planting although this increase was not significant. There were also significant positive relationships between light interception and canopy volume (m3 ha-1). When both experiments are considered the results suggest the total light interception in 1.5-year-old, high-density trees (9.2%) was similar to the total light interception of 4-year-old trees (11.0%) in the baseline study. These results highlight the benefits of high density plantings in increasing total orchard light interception earlier than in conventional low-density mango orchards. In the future, the relationships between yield, canopy volume, light interception and training systems will be further examined in the planting systems experiment. © 2018 International Society for Horticultural Science.

Using the nitrification inhibitor DMPP to enhance uptake efficiency in a fertigated peach orchard plantation

A three year experiment from 2014 to 2016 was conducted to assess the effect of a nitrification inhibitor (NI) DMPP, and nitrogen (N) application rates in a commercial peach orchard (889 trees ha-1) in a drip irrigated calcareous soil in the Ebro Valley (Lleida, Spain). The mineral content of leaves and fruits, vegetative growth and total yield were monitored each year. A significant effect of NI was observed. Increasing N application rates and the use of NI increased the tree canopy area and N content of the leaves and fruits. The use of NI could be an effective way to minimize the use of fertilizers in orchard systems, reducing the environmental impact. Yield was affected by the N dose and timing of application. The highest yield (58.6 t ha-1 with a fruit diameter higher than 65 mm) was recorded in 2015, applying only 50 kg N ha-1 plus NI, in fruit growth phase I. no negative visual effects were observed in the field except for trees with lower N doses (25 kg N ha-1). Darker leaves were visually observed in the NI treatments. More experiments need to be established to corroborate these findings.

Efecto de la exclusión de un área natural protegida en la composición y estructura arbórea

El Parque Nacional Izta-Popo es un área natural protegida (ANP) que fue creada con la finalidad de mantener la representatividad de los ecosistemas. Actualmente, no se sabe la situación de zonas que fueron excluidas de aprovechamiento forestal. El objetivo fue evaluar el efecto de la exclusión de un ANP en la composición y estructura del arbolado por medio de caracterización dasométrica de un bosque templado en la región central de México. Se seleccionaron tres sitios cuadrados de 100 x 100 m (1 ha): dos dentro del ANP (Pinus hartwegii “BPiHa” y Pinus montezumae “BPiMo”) y un bajo aprovechamiento forestal (Abies religiosa “BAbRe”), donde se midió el diámetro normal (d1.30), altura total (h), para calcular el área basal (G), volumen total (vt), diámetro promedio (d), altura promedio (h), índice de esbeltez (h/d), densidad (dn). El BPiMo tiene una densidad de 149 individuos, área basal (39.21 m2 ha-1), volumen total (941.82 m3 ha-1), diámetros promedios (55.34 cm) y altura promedio (34.15 m). El BPiHa tiene una densidad de 133 individuos, área basal (23.27 m2 ha-1), volumen total (328.47 m3 ha-1), altura promedio (21.44 m) y diámetros promedios (43.83 cm). La BAbRe, tiene una alta densidad de 315 individuos, área basal (32.37 m2 ha-1), volumen total (468.58 m3 ha-1), diámetros promedios (31.71 cm) y altura promedio (24.22 m). Los bosques dentro de las ANP (BPiMo y BPiHa) requieren de aprovechamiento maderable, con la finalidad de regenerar la masa forestal. El BAbRe se encuentra bajo manejo forestal y cumple con esa condición.

Recovery of above-ground tree biomass after moderate selective logging in a central Amazonian forest

Abstract: We examined the recovery and dynamics of living tree above-ground biomass (AGB) after selective logging in an Amazonian terra firme forest managed by a private company. The forest consisted of 24 blocks (including one set aside for conservation) selectively logged in different years on a managed schedule. Trees ≥10 cm in diameter at breast height (dbh) were surveyed in 2006 in 192 0.25-ha plots, in 2010 in 119 plots, and in 2012-2013 in 54 plots. A logistic growth model factoring in logging dynamics and mean AGB of a block in these years was established. Referencing the mean AGB of the unlogged forest, the model indicated that the logged forest would take on average 14 years to regain its preharvest AGB after selective logging at 1.9 trees ha-1 (dbh > 50 cm). In 2010 and 2012-2013, the AGB increased significantly for small and large trees (10-20 cm and >60 cm dbh, respectively) in the logged forest. In contrast, it decreased significantly for medium-sized trees (30-50 cm dbh) in the unlogged forest. Comparisons with the previous studies mainly conducted in the other regions of Amazon suggested that the estimated AGB recovery period with moderate logging intensity was almost appropriate and likely acceptable to forest managers.

ABOVEGROUND BIOMASS GROWTH AND YIELD OF FIRST ROTATION CUTTING CYCLE OF Acacia AND Eucalyptus SHORT ROTATION DENDROENERGY CROPS

ABSTRACT Chile has strong interest in biomass production for the purpose of generating bioenergy to accomplish environmental standards for clean energy production. However, no yield or productivity information is available about forest crop plantations established at high-initial planting densities dedicated to energy production. The objective of the present study was to provide long-term results of short-rotation forest crops research trials, investigating first cutting cycle most promising species biomass production. Plantations of Acacia melanoxylon, Eucalyptus camaldulensis, Eucalyptus globulus, and Eucalyptus nitens were established at initial stockings of 5,000; 7,500 and 10,000 trees ha-1 on marginal sites with important nutritional and hydric limitations in the Biobío Region, Chile. After 48 months, E. camaldulensis reached the highest biomass yield at initial stocking of 7,500 trees ha-1 (22.5 Mg ha-1) on dry land granitic soils, and E. nitens reached 35.2 Mg ha-1 on sandy soils. Initial stockings and biomass yields were directly related, but strongly conditioned by mortality, where greater initial stocking concurred with greater mortality after 4 years. The collar diameter and total height growth was lower at higher stockings.

Facultative and Obligate Trees in a Mesic Savanna: Fire Effects on Savanna Structure Imply Contrasting Strategies of Eco-Taxonomic Groups.

Fire is a major determinant of savanna tree communities and, as such, manipulation of fire frequency is an important management tool. Resolving the effects of fire management on tree size class distributions can help managers predict and plan for short-term ecological and economic outcomes, reveal different strategies by which woody plants cope with frequent fire, and help us predict vegetation changes under future fire scenarios. Savanna structure and size class distribution are strongly influenced by the ability of suppressed tree resprouts to escape stem death by frequent fire. A widespread assumption is that resprouts have an imperative to escape fire to reach sexual maturity in the canopy and thereby ensure long-term species viability. We use a census of Australian mesic savanna tree communities subjected to annual, triennial, and fire exclusion (unburnt) fire treatments to ask how fire frequency affects size class distributions within and between eco-taxonomic groups of species. Total tree densities did not significantly differ, but were highest in the triennial (7,610 ± se 1,162 trees ha−1) and unburnt fire treatments (7,051 ± se 578 trees ha−1) and lowest in the annual fire treatment (6,168 ± se 523 trees ha−1). This was caused by increased sapling densities in the triennial and unburnt fire treatments, predominantly of Acacia and pantropical genera. Eucalypts (Eucalyptus and Corymbia spp.) dominated the canopy across all fire treatments indicating relatively greater success in recruiting to larger sizes than other species groups. However, in the sub-canopy size classes eucalypts co-dominated with, and in some size classes were outnumbered by, pantropicals and Acacia, regardless of fire treatment. We hypothesize that such results are caused by fundamental differences in woody plant strategies, in particular sexual reproduction, that have not been widely recognized in Australian savannas.

Productive and nutritional characteristics of Piatã-grass in integrated systems

SUMMARY This study aimed to evaluate the pasture productive and nutritional characteristics of Brachiaria brizantha cv. BRS Piatã in integrated systems with different densities of trees. Considering as plot the systems: integrated crop-livestock-forest with rows of trees (eucalyptus) spaced at 14 m and 357 trees ha-1 (ICLF-14m), ICLF with rows of trees spaced at 22 m and 227 trees ha-1 (ICLF-22m) and the integrated crop-livestock (ICL) with five remaining native trees ha-1; period of the year as subplots, and sampling points as subsubplots (A, B C, D, and E) arranged perpendicular to trees alleys. It was evaluated the production of forage and leaf blade dry mass, leaf:stem ratio, soil coverage, radiation photosynthetically active interception, canopy height, crude protein (CP), neutral detergent fiber (NDF), in vitro digestibility of organic matter (IVDOM) of the leaf blade, and stem associated with the leaf sheath. There was a significant difference (P<0.05) for all variables due to the month within the integrated systems. Mainly in January and March, showing the forage and leaf blade dry mass reduction due to a higher trees density. System with higher trees density showed the lowest soil coverage and canopy height sampling points A and E in ICLF-22m showed lower forage and leaf blade dry mass production and soil coverage. The system with higher trees density showed lower value of NDF of the leaf blade, and higher CP contents. The IVDOM of the leaf blade was higher in ICLF systems. For the evaluated parameters the best results were for the ICLF-22m.

Pruning management in a high-density olive orchard

The effect of different pruning strategies and times on olive vegetative-reproductive behavior was studied in a 5-year-old high-density orchard (1250 trees ha-1, cultivar 'Ascolana tenera'). Compared treatments were a) winter hedging and topping, b) summer hedging and winter topping, c) winter hedging and summer topping, and d) summer hedging and topping. Selective spring pruning to a conical shape of the canopy was used as a control. Results showed no significant differences between the tested treatments regarding the maximum canopy diameter (along and perpendicularly to the row). Topping significantly constricted the tree height recorded at the end of the season when compared with the control (3.5±0.46 m); in particular, summer application maintained the final tree height at 2.5±0.21 m. Summer topping and hedging significantly reduced the canopy volume compared with winter and selective spring (control) pruning. No significant differences between the treatments were recorded regarding the number of newly emitted sprouts on the central leader and primary branches, whereas the length of these sprouts was significantly shorter for the trees with summer topping. Vegetative re-sprouting was mainly recorded in the upper portion of the canopy (above 2.0 m), and the total length of the new sprouts in this portion was significantly different for summer and winter pruning (1.2±0.08 and 18.7±0.92 m, respectively). No significant differences between the treatments were registered for the seasonal vegetative growth of 1-year-old mixed shoots. Fruit yield per tree was significantly higher following the winter hedging and summer topping treatment compared with summer hedging and topping (47% increase) and selective spring pruning (control, 64% increase). Results suggest that correct pruning management (winter hedging and summer topping) contributes to maintaining a good vegetative-reproductive balance of young trees (reduced vegetative re-sprouting and high fruit production) in high-density olive orchards.

Damage to several olive cultivars by two over-the-row harvesters in high-density orchards

The damage induced by two over-the-row harvesters was studied in several olive cultivars in two high-density orchards (1250 trees ha-1) in central Italy. A self-propelled harvester was used on 14 cultivars ('Arbequina', 'Ascolana Dura', 'Carboncella', 'Coroncina', 'Lea', 'Leccio Corno', 'Maurino', 'Mignola', 'Nostrale Di Rigali', 'Piantone di Mogliano', 'Piantone di Falerone', 'Raggia', 'Rosciola' and 'Rosciola Colli Esini') in a 4-year-old olive orchard, and a tow-behind harvester was used on 10 cultivars ('Arbequina', 'Ascolana tenera', 'Don Carlo®', 'FS17®', 'Maurino', 'Piantone di Falerone', 'Piantone di Mogliano', 'Rosciola', 'Sargano di Fermo' and 'Tosca®') in a 5-year-old olive orchard. Trees were pruned into a conical shape from planting by removing inter-row branches that were too long and to create a continuous slender hedge. The bark damage and limb breakages were monitored in 20 homogeneous trees per cultivar after harvest. Among the local cultivars, 'Maurino' and 'Piantone di Mogliano' appeared to be highly suitable for mechanical harvest and comparable with 'Arbequina'. For other cultivars, such as 'Piantone di Falerone', the initial suitability declined as the trees aged, indicating the need to evaluate plant flexibility over time. The number of branches per tree and the longitudinal diameter of the canopy were better predictors of bark and limb damage. The most vigorous and dense cultivars were most susceptible to damage. These results provide crucial information on the adaptability of local, national and international olive cultivars to high-density planting and their suitability for over-the-row harvesting.

Alternative technologies for olive mill wastewater management with emphasis on soil application

The disposal of olive mill wastewater (OMW) produced during oil extraction in Mediterranean countries creates a significant environmental problem because of the great volumes of effluent produced (10-12 Mm3 year-1), heavy pollution load (40-80 g L‑1 biological oxygen demand (BOD), 50-150 g L‑1 chemical oxygen demand (COD)) and phytotoxic properties (because of phenolic compounds). During the last 30 years, many OMW treatment methods have been proposed and tested, but their application at the olive mill level is limited because of the high investment and/or running costs and technical expertise required. Existing technologies for OMW management have been identified and evaluated with the LIFE+ OLEICO+ project following certain criteria that are currently being used in Portugal, Spain, Italy and Greece. The results show that several viable technologies for OMW treatment do exist (composting, electro-coagulation, hydrolysis-oxidation, phyto-remediation, co-digestion, energy production); however, they require capital investment and maintenance costs that cannot be afforded by a small or medium olive mill plants. On the other hand, application of OMW to olive orchards can be a low-cost alternative method for OMW treatment in regions with small olive oil mill enterprises. Annual rates up to 1500 L tree-1 were applied in five equal doses, at 20-day intervals between November and February. Soil analyses were performed before the onset and after the end of the OMW application period. The response of olive trees to OMW application was monitored by measuring plant nutritional status, photosynthesis and yield. Furthermore, the possibility of groundwater pollution by the application of fresh OMW was investigated with lysimeters. OMW-treated soil had higher K content throughout the experiment. Phenols were decomposed rapidly, and therefore the phenolic content before the onset of a new OMW application period was negligible. The nutritional status, physiology and yield of olive trees were not affected by the application of OMW. The total olive orchard area required for the annual OMW production was 3.6 ha (280 trees ha-1), which is easily available around an olive mill. The cost of application is €0.007 L‑1 OMW, which seems reasonable compared with more sophisticated methods. Detailed study for each case is required in order to determine the application dose according to soil and climatic conditions of the area. The results show that several viable technologies do exist; however, the implementation cost is not negligible.

Population and vegetation structure of ramin (Gonystylus bancanus) in secondary forests of Ketapang District, West Kalimantan, Indonesia

Muin A, Astiani D. 2018. Population and vegetation structure of ramin (Gonystylus bancanus) in secondary forests of Ketapang District, West Kalimantan, Indonesia. Biodiversitas 19: 528-534. In the tropical peatland, ramin (Gonystylus bancanus Miq. Kurz) was one of many prominent species that present in peatland forest. The species distribution is mostly in Southeast Asia peatland. The beautiful wood color, pale yellow sometimes grayish with no differentiated sapwood and heartwood with straight interlocked grain, made it become the most wanted tree species from tropical peatland.The exploitation of Ramin wood since the 1970s caused the decrease of its population in the peatland forest, led to this species being listed as an endangered species. This study aimed to search information on the Ramin population and vegetation structure left in its habitat in secondary peatland forest of Pematang Gadung and Sungai Sirih villages area of Ketapang District. The study employed a survey method, and data collection was carried out using line plots system. Data assessed were natural regeneration condition-seedling, sapling and pole growth levels-, and tree growth levels. A 20 m x 20 m size plots were continually established to form a line with the length of 550-680 m. Results showed that relatively a few Ramin was found in the forests in Sungai Sirih with a mean seedling density of only 9.9 tree ha-1, height ranges of 131 cm to 150 cm, and counted sapling level of 183 trees ha-1 with diameter ranges from 0.38 to 6.37 cm. At Pematang Gadung village, more Ramin was found, especially with a bigger diameter. Tree level (diameter >20cm) was recorded at 74.1 tree ha-1 with a contradictory far less seedling (2.8 tree ha-1), sapling level (only 1 tree ha-1) and pole level (7.4 tree ha-1) established. Based on the tree population condition and the variation of their growth level, the vegetation structure of Ramin did not describe a normal curve form in the natural forest both in the villages of Pematang Gadung and Sungai Sirih.

Financial and risk analysis of African mahogany plantations in Brazil

ABSTRACT Wood demand is increasing in quality and quantity, and economic studies are fundamental to analyze the feasibility of forest projects. These researches are in line with management and silvicultural studies, highlighting growth and yield modeling. This paper proposes an economic evaluation of implementation of African mahogany stands in Brazil under different perspectives of forest management. Data are from plantations ranging from 1.1 to 15 years old in different Brazilian regions. Financial analysis was undertaken using Net Present Value (NPV), Internal Rate of Return (IRR) and Equal Annual Equivalent (EAE) for a 20-year period considering three thinning management regimes (A - unthinned, B - one thinning at age 10 years remaining 150 trees ha-1 and C - two thinnings, first at age 8 remaining 150 trees ha-1 and second at age 15 years remaining 75 trees ha-1) considering an initial density of 278 trees ha-1. A Monte Carlo simulation was performed considering six risk variables. Results showed that the discount rate is the variable that most influences the viability of the project. All site indexes in all management regimes lead to a feasible financial return, with NPV values ranging from 25,053 to 125,780 Brazilian reais per hectare, being regimes B and C the best ones. The probability for an unfeasible investment is almost zero, highlighting African mahogany as a great forest investment opportunity, providing high interest rates values (14% to 25%), superior to most available market rates of return.

Synergy between traditional knowledge of use and tree population structure for sustainability of Cola nitida (Vent.) Schott. & Endl in Benin (West Africa)

Cola nitida is a West African tree, commonly used for pharmaceutical purposes. In Benin, the species is used for many purposes ranging from traditional rituals to domestic consumption. Nowadays, the species, as well as its offspring, are hardly encountered. So far, research on the species focused on a single domain such as ethnobotany and phytochemistry. The current paper used a holistic approach to explain the species scarcity in the natural habitats using (1) the rural knowledge pattern on C. nitida and (2) the tree population structure. Semi-structured interviews (n = 170 respondents) were conducted and combined with ecological inventory (n = 38 plots) in the phyto-geographical districts of Coast and Pobe in southern Benin. The indices of diversity, equitability, and consensus quantified the range, the evenness, and the relative reliability of rural communities’ knowledge. Moreover, the plant part index gave the most used part of the tree. The knowledge on the species was unevenly distributed according to the gender, while the cofactor age did not have a statistically significant effect (P = 0.902) on the pattern. In addition, seeds represented the most used plant part (PPI = 0.59). C. nitida tree demographic structure showed a low density of seedling and sapling (1.05 ± 0.47 trees ha-1). Diameter size fitted with a two-parameter Weibull distribution indicated a threat of species extinction. The multiple uses of C. nitida seeds do not allow natural regeneration of the species. The domestication of C. nitida tree and the establishment of Cola garden/orchard in the surveyed districts are suggested for sustainable use of the species.

Productivity and costs of two low-investment biomass harvesting systems applied in a situation of mixed forest of semi-natural regeneration

SUMMARY: This study identifies the most influential variables in harvesting operations and compares the productivity and costs of two low-investment biomass harvesting system for young trees, likely to be used by owners of small and medium-sized forests in south-central Chile. The focus is harvesting the natural regeneration of Acacia melanoxylon, characterized by a high density, around 6,900 trees ha-1, with an average diameter at breast height (DBH) of 5.5 centimeters, under the cover of a Eucalyptus globulus plantation established in 2004 in Valdivia, Los Rios region, Chile. Whole-tree harvesting was used and included felling and skidding activities. In the motor-manual system, felling was carried out with chainsaws and skidding with oxen. In the semi-mechanized system, two chainsaws equipped with a felling frame and a farm tractor with grapple for skidding were used. Time studies were done, productivity models were developed and harvesting costs were calculated. The cost of both harvesting systems was relatively similar, for an 80-meter average skidding distance, with an average cost of 24.7 USD Mgw -1 (wet weight) in the motor-manual system and 24.0 USD Mgw -1 in the semi-mechanized system. Understory density and terrain slope had a highly significant impact on productivity and felling costs. For skidding, the hauling distance and skidding capacity significantly affected productivity and costs, while terrain slope, with ranges between 0 and 20 %, had no significant effects on productivity.

Planting density effect on some properties of Schizolobium parahyba wood

This study aims to understand the effect of the initial planting density on the anatomical variability and basic wood density of Schizolobium parahyba var. amazonicum in a planted forest in Amazonia. The effect of the initial planting density on the radial variation from pith to bark of anatomy and basic density was evaluated. There were two planting densities, planting density-I (624 trees ha-1) and planting density-II (312 trees ha-1). Planting density significantly affected only the ray height, fiber length and wall thickness. Radial position was not significant to the height of the rays and the fiber lumen diameter. The interaction planting density × radial position was only significant for the length of the vessel elements, ray frequency and fiber length. The results indicate that the initial planting density influences the radial behavior of certain anatomical characteristics. To obtain gain in terms of total wood per cultivated area, without harm to the density of the produced wood, planting density-I would be most useful, while planting density-II would be suitable for the production of more homogeneous wood, which tends to form adult wood in advance and with some anatomical characteristics appropriate for the plywood industry.

Corn yield for silage and grains in different integrated crop-livestock systems

In this study, the objective was to assess the influence of two doses of N (90 and 180 kg N ha-1, added to the winter pastures), two integrated crop-livestock systems (ICLS, with and without trees) and five positions between the tree rows, on the corn (Zea mays L.) quality and productivity, for silage and grain. Adopting the complete randomized block design, the treatments included three replicates. In 2006, following the 14 x 3 m spacing (currently with 158 trees ha-1) the trees were planted in 6 out of the 12 paddocks. While the corn was implemented during summer of 2013/2014, cattle grazing on the annual pasture was done during the prior winter, in both ICLS. Corn for silage was reaped at the R5 phenological stage, whereas for grains it was done at 176 days post seeding. For silage, the corn plants were grinded and then stocked in the experimental mini PVC silos. The silage varied slightly in quality along the positions between the tree rows. The differences observed between N levels in the dry matter, crude protein (CP) and grain productivity are expressions of the residual effects of the winter fertilization. Silage quality was improved by the shade effect which minimized the acid detergent fiber and raised the CP, although it reduced the corn production for silage and grains by 52%. Some feasible techniques to reduce these losses are discussed.

Using the semi-dwarfing rootstock ‘Controller 9’ to develop a pedestrian orchard for Prunus persica

In 2008, a trial was initiated at the University of California Kearney Agricultural Center to compare a standard height nectarine orchard to a “ladderless” pedestrian orchard. Nemaguard and Controller 9 rootstock were planted in May 2008 and grafted in January 2009 to the early nectarine 'Zee Fire'. Nemaguard is the standard rootstock used in the California fresh-peach industry and Controller 9 provides about 90% the vigor of Nemaguard. Trees were grown in either a 6 leader Hex-V configuration spaced at 3.7×5.3 m with a density of 561 trees ha-1, or as a 4 leader Quad-V at 2.1×4.3 m with a density of 1100 trees ha-1, and were maintained at a conventional height of ~3.7 m or a pedestrian height of 1.8-2 m. Four systems were studied: 1) conventional Nemaguard/Hex-V; 2) pedestrian Nemaguard/Hex-V; 3) pedestrian Controller 9/Hex-V; and 4) pedestrian Controller 9/Quad-V. The trees produced commercial yields beginning in 2010. The pedestrian C-9/Quad trees had the greatest yield, crop load, and fruit size in the first three harvest years; significantly outperforming the tall, high-vigor, conventional treatment. The other two pedestrian height treatments performed similar to the conventional treatment. A spring frost occurred in 2013, reducing crop loads in all treatments but affecting short trees the most.

Beef cattle production in established integrated systems

The aim of the current study is to assess three integrated systems presenting different eucalyptus tree densities due to animal and forage production. The following integrated systems were assessed: crop-livestock-forest with 357 eucalyptus trees ha-1 (ICLF1); crop-livestock-forest with 227 eucalyptus trees ha-1 (ICLF2); and crop-livestock with 5 remnant native trees ha-1 (ICL). The randomized block experimental design was applied in a split-plot scheme with four replicates. The Average Daily Gain (ADG, g animal-1day-1) and the live-weight gain per area (LWG, kg ha-1) were applied to analyze animal performance, which was set by weighing the animals every 28 days (the animals previously fasted for 16h). Forage yield was higher in ICL during fall and winter; in summer, it did not differ from ICLF2. There was no forage yield difference between the ICL and ICLF2 systems in any of the assessed seasons; summer was more productive in ILPF1 than other seasons. The highest leaf crude protein contents (CP) in summer was recorded in systems ICLF1 and ICLF2, and the highest value recorded in fall was found in ILPF1; the lowest was found in ILP. On the other hand, the highest leaf NDF contents in summer were found in ILP. The highest ADG were found in summer. The highest LWG values recorded for the ICL and ICLF2 systems were collected in summer and fall; there was no difference in any of the three systems in winter. The LWG was higher in all system in summer. The ICLF2 emerged as the system (with trees) most appropriate for beef cattle production. Despite the shading interference on forage production, such condition is compensated by the best nutritional contents such as CP. The ICLF2 system allowing an annual LWG of 83% in relation to the ICL system during the fifth year of establishment of the systems.

Producción de hojarasca y atributos estructurales del manglar en la Laguna Mecoacán, Golfo de México.

Abstract: Mangroves are tropical species established along topographic gradients in coastal areas, where variations in salinity and flooding periods influence the composition and characteristics of primary productivity. In this paper the structural attributes and litter production of mangroves of the Mecoacan lagoon, Gulf of Mexico were evaluated. In six monitoring sites the floristic composition, diameter at breast height (DBH), height, density mature mangrove trees, juveniles, recruits and seedlings, extraction and mortality were determined. Besides, basal area, importance value index (IVI), coverage and Holdridge complexity index, were calculated. Productivity litter of different mangrove species was quantified by trapping capture, while the physico-chemical parameters in surface, interstitial and groundwater were determined by installing piezometers. The study sites in Mecoacan lagoon were classified into two physiographic types: fringe (Boca, Aspoquero, Arrastradero and Pajaral) and basin (Cerros and Mojarrero). 2 854 mature mangrove trees were measured, where 93% belonged to living trees, 4.4% of extracted trees, and 2.6% dead trees standing. The average density was 2 870 mature mangrove trees ha-1. The highest basal area was found in Pajaral (41.7 m-2 h-1). Avicennia germinans (L.) Stearn presented IVI values higher everywhere, for its high relative density. An average cover of 17.5 m2 was registered. The highest rate in complexity was registered in Cerros (27.5). The species showed zonation with salinity levels of interstitial water; A. germinans located in areas of high salinity (hypersalines) while Laguncularia racemosa (L.) Gaertn and Rhizophora mangle L. in areas of lower salinity. Litter production was 5.15 t ha-1 yr-1, it showed a positive correlation with rainfall and high negative correlation with salinity levels and ORP interstitial and groundwater. Results indicate that variability in the composition and structure of mangrove the Mecoacan, is locally determined by the ability to adapt to environmental conditions (salinity, redox potential) and interspecific relationships of the species present.