scholarly journals The effect of Broussonetia papyrifera invasion on the regeneration of selected native timber species in a tropical moist forest in Uganda

2021 ◽  
Author(s):  
Davis Mark Ssemanda ◽  
Enock Ssekuubwa
Keyword(s):  
Tropical Forests ◽  
Linear Models ◽  
Block Design ◽  
Basal Area ◽  
Timber Production ◽  
Timber Species ◽  
Production Potential ◽  
Broussonetia Papyrifera ◽  
Randomized Block Design ◽  
Moist Forest

Abstract Broussonetia papyrifera has been identified as one of the top invasive species in some African tropical forests with potentially devastating impacts on the conservation and timber production potential of the forests. This study determined the effect of B. papyrifera on the regeneration of selected native timber species in Mabira Forest Reserve, Uganda. The abundance, basal area and population structure of the timber species were compared between areas invaded and uninvaded by B. papyrifera. Employing a complete randomized block design, a total of forty plots (30 x 30 m each), and equally distributed between invaded and uninvaded areas with similar habitat conditions were surveyed. Counts of seedlings were recorded and diameter of saplings and trees measured. Generalized linear models were used to analyze the abundance, tree basal area and size class distributions of the selected species. The study revealed that the effects of B. papyrifera invasion vary depending on the growth stage and species studied. Overall, B. papyrifera invasion significantly reduced tree abundance and basal area, and suppressed the regeneration of some but not all the selected species. Our results demonstrate that if the spread of B. papyrifera is not abated, it will lower the conservation and timber production potential of tropical forests. Therefore, we call for interventions to control the spread of B. papyrifera to the uninvaded parts of the forests and halt its multiplication in invaded areas so as to enhance the regeneration and growth of timber species.

scholarly journals Calli induction in leaf explants of coffee elite genotypes

2011 ◽  
Vol 41 (3) ◽  
pp. 384-389 ◽  
Author(s):  
Juliana Costa de Rezende ◽  
Carlos Henrique Siqueira de Carvalho ◽  
Moacir Pasqual ◽  
Ana Carolina Ramia Santos ◽  
Stephan Malfitano de Carvalho
Keyword(s):  
Coffea Arabica ◽  
Block Design ◽  
Leaf Explants ◽  
Production Potential ◽  
Embryogenic Calli ◽  
The Third ◽  
Randomized Block Design ◽  
Indirect Somatic Embryogenesis ◽  
Growth Room ◽  
Opposite Behavior

Three experiments were carried out with the objective of achieving high effectiveness in calli induction from high heterozygosis leaf explants of Coffea arabica through indirect somatic embryogenesis. A randomized-block design in a 2x5 factorial arrangement made up of two media [BOXTEL & BERTHOULY (1996) and TEIXEIRA et al. (2004)] and five C. arabica genotypes were used in the first experiment. In the second experiment the embryogenic calli production potential was evaluated in ten genotypes. Each of them was considered as a treatment. In the third experiment the variations in both 2.4-D (2.5 e 20µM) and 2-iP (2.5 e 20µM) concentrations in TEIXEIRA et al. (2004) medium and secondary media were evaluated. Crops were kept in a growth room under darkness, at 25±2oC. The medium described by TEIXEIRA et al (2004) was found to be superior when compared to that described by BOXTEL & BERTHOULY (1996) in the 2.2 and 7.2 genotypes. An opposite behavior was noticed in 4.2 genotype, that is, BOXTEL & BERTHOULY (1996) had medium superiority. Both 3.0 and 5.0 genotypes had the same behavior in both media studied, which shows that the somatic embryo production depends on the genotype. Calli induction depends on the 2-iP and 2.4 D ratio. The 20.0µM of 2.4-D and 20.0µM of 2-iP combination caused the highest embryogenic calli induction rate.

scholarly journals Mid-Term Effects of Forest Thinning on N Mineralization in a Semi-Arid Aleppo Pine Forest

Forests ◽  
2021 ◽  
Vol 12 (11) ◽  
pp. 1470
Author(s):  
Inmaculada Bautista ◽  
Luis Lado-Monserrat ◽  
Cristina Lull ◽  
Antonio Lidón
Keyword(s):  
N Mineralization ◽  
Nutrient Dynamics ◽  
Pinus Halepensis ◽  
Block Design ◽  
Plant Cover ◽  
Basal Area ◽  
Net N Mineralization ◽  
Mineral N ◽  
Silvicultural Treatments ◽  
Randomized Block Design

In order to assess the sustainability of silvicultural treatments in semiarid forests, it is necessary to know how they affect the nutrient dynamics in the forest. The objective of this paper is to study the effects of silvicultural treatments on the net N mineralization and the available mineral N content in the soil after 13 years following forest clearings. The treatments were carried out following a randomized block design, with four treatments and two blocks. The distance between the two blocks was less than 3 km; they were located in Chelva (CH) and Tuéjar (TU) in Valencia, Spain. Within each block, four experimental clearing treatments were carried out in 1998: T0 control; and T60, T75 and T100 where 60%, 75% and 100 of basal area was eliminated, respectively. Nitrogen dynamics were measured using the resin tube technique, with disturbed samples due to the high stoniness of the plots. Thirteen years after the experimental clearings, T100, T75 and T60 treatments showed a twofold increase in the net mineralization and nitrification rates with respect to T0 in both blocks (TU and CH). Within the plots, the highest mineralization was found in sites with no plant cover followed by those covered by undergrowth. These results can be explained in terms of the different litterfall qualities, which in turn are the result of the proportion of material originating from Pinus halepensis Mill. vs. more decomposable undergrowth residues.

scholarly journals Growth After Thinning a 35-Year-Old Natural Stand to Different Loblolly Pine and Hardwood Basal Areas

1997 ◽  
Vol 21 (4) ◽  
pp. 168-174
Author(s):  
Michael G. Shelton ◽  
Paul A. Murphy
Keyword(s):  
Loblolly Pine ◽  
Block Design ◽  
Volume Growth ◽  
Basal Area ◽  
Timber Production ◽  
Product Class ◽  
Randomized Complete Block Design ◽  
Timber Products ◽  
Total Growth ◽  
Area And Volume

Abstract Growth was monitored for 4 yr in a thinned stand in southern Arkansas with three pine basal areas (70, 85, and 100 ft2/ac) and three hardwood basal areas (0, 15, and 30 ft2/ac); pretreatment basal areas averaged 119 and 33 ft2/ac for pines and hardwoods, respectively. Treatments were arranged in a 3 X 3 factorial randomized complete block design with three replicates, yielding 27 permanent 0.20 ac plots. Growth variables were regressed with residual pine and hardwood basal areas. Pine basal area and volume growth increased with the pine stocking level after thinning and decreased with the level of retained hardwoods. For basal area and merchantable volume, hardwood growth largely compensated for losses in the pine component, and thus, hardwood retention had little net effect on the total growth of the stand. The greatest impact of hardwood retention was on the stand's sawtimber growth, because hardwoods did not contribute to this product class. Each 1 ft2/ac of retained hardwood basal area reduced pine sawtimber growth by 6 to 10 bd ft Doyle/ac/yr, depending on the pine stocking. Because large differences existed in the value of timber products, retaining 15 and 30 ft2/ac of hardwoods reduced the value of timber production by 13 and 24%, respectively, at 4 yr after thinning. South. J. Appl. For. 21(4):168-174.

scholarly journals EFICIÊNCIA DE DUAS VARIAÇÕES ESTRUTURAIS DO MÉTODO DE AMOSTRAGEM DE ÁREA FIXA EM PLANTAÇÕES DE Pinus taeda

FLORESTA ◽  
2013 ◽  
Vol 43 (4) ◽  
pp. 621
Author(s):  
João Paulo Druszcz ◽  
Nelson Yoshihiro Nakajima ◽  
Sylvio Pellico Netto ◽  
Sebastião do Amaral Machado ◽  
Nelson Carlos Rosot ◽  
...  
Keyword(s):  
Pinus Taeda ◽  
Relative Efficiency ◽  
Block Design ◽  
Basal Area ◽  
Average Diameter ◽  
Breast Height ◽  
Variable Diameter ◽  
Randomized Block Design ◽  
Fixed Area ◽  
Pinus Taeda L

Este estudo foi conduzido em três diferentes condições de plantações de Pinus taeda L., sem desbastes, com 10, 9 e 7 anos de idade, 2.000 árvores por hectare e diferentes inclinações no terreno, localizados no Estado do Paraná. O objetivo foi avaliar a eficiência do inventário florestal, utilizando-se a amostragem de área fixa com a estrutura de parcela circular (PC) e conglomerado em cruz (CC), através da análise do comportamento quanto às precisões e eficiências relativas nas estimativas das seguintes variáveis: diâmetro médio (cm), número de árvores por ha, área basal (m2/ha) e volume total (m3/ha). Para isso, utilizou-se o delineamento em blocos casualizados com 40 unidades amostrais para a PC e 10 unidades para o CC, sendo este composto por 4 subunidades circulares. Concluiu-se que, para as variáveis diâmetro médio (cm), número de árvores (N/ha), área basal (m2/ha) e volume total (m3/ha), indica-se a utilização do método de área fixa com PC, tendo em vista a maior eficiência no levantamento dessas variáveis.Palavras-chave: Eficiência relativa; precisão; reflorestamento. AbstractStructural efficiency of two variations of method of sampling of fixed area in plantations of Pinus taeda. This study was carried out in three different stands of Pinus taeda L., unthinned and aged 10, 9 and 7 years. The stands have 2.000 trees per hectare and are located in Parana State. The aim was to evaluate the efficiency of inventories using circular plot (PC) and cross cluster (CC) by analyses of behavior towards accuracies and relative efficiencies for estimation of the following variables: average diameter at breast height, number of trees, basal area and total volume per hectare. For this study, it was taken a sample of 40 units to the PC structure and 10 units for the CC structure, which is composed of four circular subunits, and it was used the randomized block design. It was concluded that for the variable diameter (cm), number of trees (ha), basal area (m2/ha) and total volume (m3/ha) it is indicated the use of PC, since its greater efficiency in the survey of these variables.Keywords: Relative efficiency; accuracy; reforestation.

scholarly journals Effect of Sea Mud Towards The Growth and Productivy of Several Varieties of Shallotin Peat Land

2016 ◽  
Vol 4 (2) ◽  
Author(s):  
Azri , ◽  
Muhammad Hatta ◽  
Wahyu Ari Nugroho
Keyword(s):  
Block Design ◽  
Research Result ◽  
Production Costs ◽  
Production Potential ◽  
West Kalimantan ◽  
Local Resources ◽  
Randomized Block Design ◽  
Sea Mud ◽  
High Production ◽  
Profit Value

<p><strong><em>ABSTRACT</em></strong></p><p><em> </em></p><p><em>Shallot cultivation in peat land was constrained by the high production costs, especially fertilizer and lime costs (Abdullah, 2011). Therefore, improvement of shallot productivity in peat land was to use local resources so that the production costs would be reduced. Potential material to be used for that purpose was sea mud which abundantly available in West Kalimantan. The productivity of several shallot varieties in peat land had not reached their production potential. The research used Randomized Block Design (RBD) with the treatment of sea mud consisted of without the treatment of sea mud (L<sub>0</sub>) and with the treatment of sea mud (L<sub>1</sub>) and several shallot varieties such as Bima Variety (V1), Manjung Variety (V2) and Sumenep Variety (V3). The research result showed that the treatment of sea mud and varieties of shallot differed significantly in improving the growth and production of shallot. Bima, Manjung and Sumenep each produced </em><em>14.73 ton/ha, 12.84 ton/ha and 9.22 ton/ha respectively. Based on profit value and B/C ratio value, the utilization of sea mud in peat land was economically feasible to be applied by farmers in West Kalimantan.</em></p><p><em> </em></p><p><em><br /></em></p>

Effect of cutting intensity on microenvironmental conditions and regeneration dynamics in yellow birch – conifer stands

2008 ◽  
Vol 38 (2) ◽  
pp. 317-330 ◽  
Author(s):  
Marcel Prévost
Keyword(s):  
Seedling Recruitment ◽  
Block Design ◽  
Light Availability ◽  
Abies Balsamea ◽  
Basal Area ◽  
Soil Disturbance ◽  
Betula Alleghaniensis ◽  
Yellow Birch ◽  
Partial Cutting ◽  
Randomized Block Design

This paper presents the 5 year results of different cutting intensities (removal of 0%, 40%, 50%, 60%, and 100% of the basal area) applied in two mixed yellow birch ( Betula alleghaniensis Britt.) – conifer stands of eastern Quebec, Canada. Two sites 90 km apart were used: Armagh and Duchesnay. Each site had four replicates of the treatments in a randomized block design. The effect on light availability was similar in the two sites: the 0%, 40%, 50%, 60%, and 100% cuts transmitting a mean of 5%, 21%, 26%, 30%, and 94% of full light, respectively, during the first summer. Soil temperature increased only in the 100% cut (4−5 °C, maximum daily temperature). Soil disturbance during harvest was higher at Duchesnay than at Armagh, which clearly improved seedbed receptivity, particularly to yellow birch. After 5 years, treated areas contained 21 000 to 48 300 seedlings/ha at Duchesnay compared with 5500 – 10 500 seedlings/ha at Armagh. Significant losses of coniferous advance growth were observed at both sites, but a subsequent seedling recruitment occurred only at Duchesnay. Red spruce ( Picea rubens Sarg.) showed superior establishment in the 60% cut (4400 seedlings/ha) than under other cutting intensities (1600–2100 seedlings/ha), whereas balsam fir ( Abies balsamea (L.) Mill.) responded well to all partial cutting treatments. At both sites, pin cherry ( Prunus pensylvanica L.f.) was the main competing species in the 100% cut, whereas densities of the preestablished mountain maple ( Acer spicatum Lamb.) and striped maple ( Acer pensylvanicum L.) either remained the same or increased in the partial cuts.

scholarly journals Defoliation percentage in two soybean cultivars at different growth stages

2015 ◽  
Vol 19 (6) ◽  
pp. 567-573 ◽  
Author(s):  
Cláudio A. da S. Glier ◽  
José B. Duarte Júnior ◽  
Gabriel M. Fachin ◽  
Antonio C. T. da Costa ◽  
Vandeir F. Guimarães ◽  
...  
Keyword(s):  
Grain Yield ◽  
Block Design ◽  
Growth Stages ◽  
Production Potential ◽  
Soybean Cultivars ◽  
Randomized Block Design ◽  
Different Levels ◽  
Different Growth Stages ◽  
Phenological Phases

ABSTRACT The objective of this study was to evaluate the agronomic variables due to the effects of different levels of defoliation in the phenological phases of two soybean cultivars. The experiment was conducted during the 2011/2012 season, in a randomized block design with three replicates, in a 2 x 4 x 5 factorial scheme. Two cultivars were exposed to defoliations of 0, 25, 50, 75 and 100% at the stages of V4, V9, R3 and R5. The cultivar 'NK 7059RR' showed less sensitivity to defoliation than the cultivar 'IN 4990RG'. 25% defoliation levels reduced the yield of the cultivar 'IN 4990RG', while levels of 75 and 100% reduce the number of grains per pod in both cultivars. The defoliation performed in the V4 stage lead to lower grain yield than defoliation in V9. The most sensitive stages to defoliation are R3 and R5, where there is a greater reduction in the production potential of soybeans.

scholarly journals EFFICIENCY OF ATTRACTORS AND TRAPS FOR CAPTURE OF SPOTTED-WING DROSOPHILA IN VINEYARDS1

2021 ◽  
Vol 34 (4) ◽  
pp. 830-836
Author(s):  
DAHISE BRILINGER ◽  
CRISTIANO JOÃO ARIOLI ◽  
SIMONE SILMARA WERNER ◽  
JOATAN MACHADO DA ROSA ◽  
MARI INÊS CARISSIMI BOFF
Keyword(s):  
High Efficiency ◽  
Linear Models ◽  
Insect Pests ◽  
Block Design ◽  
Spotted Wing Drosophila ◽  
Drosophila Suzukii ◽  
Plastic Container ◽  
Pest Monitoring ◽  
Randomized Block Design ◽  
Capture Method

ABSTRACT Pest monitoring is a practice that enables the estimation of populational density of insect-pests in crops. However, it requires the use of attractors and traps that present high efficiency. The objective of this work was to evaluate the efficiency of food attractors using different trap models for the capture of spotted-wing drosophila (Drosophila suzukii) insects, and the capture selectivity of these models in vineyards of Cabernet Sauvignon. The experiment was conducted in the 2018-2019 crop season, in São Joaquim, SC, Brazil. A randomized block design was used, in a 2 × 4 factorial arrangement consisted of two types of traps (PET bottle and plastic container), three attractors (SuzukiTrap®, Droskidrink, and Yeast), and distilled water as a control. The traps were distributed in a minimum distance of 15 m and fixed in the middle third of the plants. The collections and replacing of attractors were done with 21-day intervals. The data were analyzed through generalized linear models, using the Poisson distribution or Poisson with a dispersion parameter. All attractors tested captured adult D. suzukii insects. No significant differences were found between the trap types used. The findings of the present work showed that the trap plastic container with the Droskidrink attractor is the most suitable capture method to be used in monitoring programs for D. suzukii insects in commercial vineyards.

scholarly journals Challenges in chemical management of soybean looper (Chrysodeixis includes) using several insecticides

2019 ◽  
pp. 1723-1730 ◽  
Author(s):  
Clerison R. Perini ◽  
Jonas A. Arnemann ◽  
Lucas de A. Cavallin ◽  
Gabriel A. Guedes ◽  
Rafael P. Marques ◽  
...  
Keyword(s):  
High Mortality ◽  
Linear Models ◽  
Block Design ◽  
Larval Density ◽  
Type I ◽  
Block Designs ◽  
Randomized Block Design ◽  
Soybean Leaf ◽  
Soybean Looper ◽  
Randomized Block Designs

Soybean looper, Chrysodeixis includens (Walker, [1858]) (Lepidoptera: Noctuidae), is the most important caterpillar pest in Brazil due to its high tolerance to insecticides and control failures that have been reported in fields. Based on this, we assessed the performance of several insecticides against C. includens on soybean over three seasons (2014, 2015, and 2016), performing four experiments in southern Brazil. Experiments I / 2014, II / 2015, III / 2016 were carried in completely randomized block designs with eight insecticides. Experiment IV / 2016 was arranged in completely randomized block design in an 8 x 2 factorial arrangement, eight insecticides x two spraying time. Mortality of small (< 1.5 cm) and large (> 1.5 cm) soybean looper larvae was assessed with a vertical beat cloth, sampling in each plot 1.0 m2 at 3, 7 and 10 days after spray. Percentage of defoliation injury was assessed visually comparing to a scale of soybean leaf injury in experiment IV / 2016. Data were subjected to one-way (type I SS) analysis of variance (ANOVA) using the general linear models. The insecticides indoxacarb and chlorfenapyr had consistently high mortality upon small and large larvae of C. includens. Spinosyn, spinosad and spinetoram insecticides showed higher effect over small larvae (< 1.5 cm) than large (> 1.5 cm). Number of spraying was significant for spinetoram and indoxacarb that increased mortality of large larvae (from 4.50 to 2.75 and from 3.75 to 0.87 larvae m-2, respectively) and reduced defoliation injury significantly (from 22.5% to 9.3% and from 14.5% to 3.3%, respectively) with two applications. The treatment chlorfluazuron+acephate showed low defoliation injury in 2016 but did not affect larval density. Chlorfenapyr showed reduced defoliation (3.0%) and low larvae density (1.37 larvae m-2) with only one application. Spinosyns have satisfactory control of small larvae and indoxacarb and chlorfenapyr show high mortality of both sizes, small and large larvae. Therefore, we recommend that 7 days from the first one, a second application should be considered for indoxacarb, and spinetoram to achieve higher mortality. Considering our results, we demonstrate that the satisfactory control of soybean looper larvae is difficult to achieve with most chemical insecticides. It needs a more accurate management strategy of C. includens in soybeans.

scholarly journals KARAKTERISTIK FISIK dan PRODUKSI KELAPA DALAM (Cocos nucifera L) di BERBAGAI EKOLOGI LAHAN

2016 ◽  
Vol 1 (2) ◽  
pp. 45 ◽  
Author(s):  
Rudi Hartawan ◽  
Arif Sarjono
Keyword(s):  
Sea Level ◽  
Crop Production ◽  
Survey Methods ◽  
Cocos Nucifera ◽  
Block Design ◽  
Community Gardens ◽  
Adaptation Level ◽  
Production Potential ◽  
Randomized Block Design ◽  
Cocos Nucifera L

AbstractThe growing environment plays an important role in the plant's phenotype. The suitability of the environment will bring up the genetic potential mainly on coconut production. The expected output of this research is to know the adaptation level of coconut crops different land ecology. The research was carried out in January to August 2016 at: 1) tidal lands in Lagan Ulu village of Geragai Sub-district of  Tanjung Jabung Timur with altitude 0-10 m above sea level, 2) in the lowland Ramin village Kumpeh Ulu Subdistrict Muaro Jambi regency with a height of 10-100 m above sea level, 3) Moderate land in Wanareja village of Rimbo Ulu Subdistrict Tebo regency with an altitude of 100-500 m above sea level and 4) Highland in Seberang village Sungai Penuh subdistrick Sungai Penuh City, with an altitude 500 m above sea level. Laboratory analysis conducted in July 2016 in  laboratorium dasar University Batanghari. Research conducted by survey methods in community gardens and arranged in environment randomized block design namely tidal areas, lowland, moderate land, and highland. Each altitude of land was three farmers. Porposifly as a block of design. The parameters are the palnt physical, reproduction age, agronomy, action estimation of production potential, soil acidity and daily temperatures. Data of research are analyzed by description method such as tabulated data form and anova test (α=5%) was used of inferential analysis. The result of this research showed that there was a significantly effect of land altitude on production potential and phisical characteristic of coconut trees. The coconut trees showed optimally growth and production in moderate land (100-500m above sea level). Keywords: coconut, cultivation, crop production. AbstrakLingkungan tumbuh berperan penting dalam produksi tanaman Kelapa Dalam. Tujuan dari penelitian ini adalah mengetahui tingkat adaptasi tanaman Kelapa Dalam pada berbagai ekologi lahan. Penelitian dilaksanakan pada bulan Januari sampai Agustus 2016 di: 1) lahan pasang surut di Desa Lagan Ulu, Kecamatan Geragai, Kabupaten Tanjung Jabung Timur dengan ketinggian 0-10 m dpl, 2) dataran rendah di Desa Ramin, Kecamatan Kumpeh Ulu, Kabupaten Muaro Jambi dengan ketinggian 10-100 m dpl, 3) dataran sedang di Desa Wanareja, Kecamatan Rimbo Ulu, Kabupaten Tebo dengan ketinggian 100-500 m dpl dan 4) dataran tinggi di Desa Seberang, Kecamatan Sungai Penuh, Kota Sungai Penuh, dengan ketinggian >500 m dpl. Analisis laboratorium dilakukan pada bulan Juli 2016 di Laboratorium Dasar Universitas Batanghari. Penelitian dilakukan dengan metode survey di kebun-kebun masyarakat dan disusun dalam rancangan lingkungan acak kelompok dengan rancangan perlakuan ekologi lahan yaitu daerah pasang surut, dataran rendah, dateran sedang dan dataran tinggi. Tiap-tiap ekologi lahan diambil tiga petani sampel secara sengaja yang dijadikan blok dalam rancangan. Peubah yang diamati adalah fisik tanaman, umur berproduksi, tindakan agronomi, estimasi potensi produksi, kemasaman tanah dan suhu harian. Data hasil penelitian dianalisis dengan metode deskripsi dalam bentuk tabulasi dan inferensi dilakukan dengan uji anova taraf α 5%. Hasil penelitian menunjukkan Ekologi lahan berpengaruh nyata terhadap potensi produksi dan karakteristik fisik tanaman Kelapa Dalam. Tanaman Kelapa Dalam dapat tumbuh, berkembang dan berproduksi dengan baik di daerah dataran sedang dengan ketinggian 100-500 m dpl. Kata kunci: Kelapa Dalam, budidaya, produksi tanaman

Sign in / Sign up

Export Citation Format

Share Document