CREA Journals (Consiglio per la ricerca in agricoltura e l’analisi dell’economia agraria)
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A narrow size diameter class model for tree growth and yield simulation in a mahoe (Talipariti elatum (SW.) Fryxell, Malvaceae) plantation in Puerto Rico
Get PDFForest management planning requires forest growth models that provide a reliable way to forecast growth, calculate yield, and examine the effects of silviculture. Here we used a size stem frequency approach based on differential equations to developed a growth simulator system to guide the management of mahoe (Talipariti elatum (SW.) Fryxell) in a small plantation in Puerto Rico. We estimated the optimal harvest age using the Faustmann model, and evaluated alternative harvesting schemes using sensitivity analyses. The growth simulator system predicted that tree volume at first rises quickly, reaches a maximum value, and then decreases because of a lack of natural regeneration in the plantation. Thus, harvesting must be followed by replanting and large and healthy trees must be maintained as seed sources. The optimal harvest age was 43 years for a discount rate of 2.5% and 19 years for 5% interest. Analysis for alternative management schemes based on selective harvesting of the largest tress showed that 5%, 15%, or 30% of the trees ≥54.5 cm dbh could be harvested in cycles of 1, 5 or 10 years respectively, without drastically decreasing the basal area. The sustainability of these management schemes will depend on the costs of management, as well as the responses of mahoe to selective harvesting.
A multi-temporal dataset of forest mensuration of reforestations: a case study in peri-urban Rome, Italy
Get PDFThe dataset supplied in this article provides data from continuous forest inventory carried out in the Castel di Guido estate, located in the Italian Tyrrhenian coast. The reforestation project started over 30 years ago using native and non-native species: 29 forested plot areas have been surveyed in 1997, 2000, 2003, 2006, 2011, 2013 and 2017 where information about species and stem diameters have been collected for a total of 2’215 tree stems. The dataset also contains height-diameter curves modelled for 1997, 2006 and 2017 years to let the user to estimate growing stock and total biomass easily. These data can be exploited to assess net primary productivity, pollutant uptake, and as comparisons with other European artificial reforestations programs with similar species. The database is finalized to narrow the knowledge gap on long-term growth pattern of urban and peri-urban reforestations, providing comparative data on different species performances, grown in pure and mixed stands. Dataset and metadata here presented are available at https://doi.org/10.5281/zenodo.2633972
Modelling Crown-Stem Diameters Relationship for the Management of Tectona grandis Linn f. Plantation in Omo Forest Reserve, Western Nigeria
Get PDFCrown-stem diameter relationship is important for sustainable forest management. Effective forest management requires routine inventory data of tree crops for decision making. Therefore, in this study, crown-stem diameter relationship was modelled for the management of Tectonia grandis L. f. plantation in Nigeria. The dataset consists of 1919 trees measured from 35 sample plots. Three methods including ordinary least square (OLS), quantile regression (QR) and linear mixed model (LMM) were used to model the relationship between crown diameter (CD) and diameter at breast height (DBH). The model was used to estimate the limiting density, growing space and projection area. The result shows that the model from LMM was more suitable than OLS and QR. It explained 0.622 of the variation in CD with root mean squared error of 0.736. The study also shows e.g., that T. grandis trees of 25 cm DBH would occupy an equivalent area 36.32 m2 and to avoid inter-tree competition the stand density should not exceed 275 Nha-1. And if the plantation is to be thinned and clear-felled when mean DBH is 50 cm, density remaining after thinning would be 115 Nha-1 with average growing space of 9.3 m. This information would help in the management of the plantation
SIGHTING OF SOUTHERN GREY SHRIKES PREYING ON RED PALM WEEVILIN TWO COUNTRIES
Get PDFRhynchophorus ferrugineus, commonly known as Red Palm Weevil, is one of the most destructive and invasivepalm pests’ species in the world. The most important host species are coconut palms, oil palms, Canary Island palms and itis considered as a key pest in date palms crops. As the existing chemical – based treatments are not efficient, the eco-friendly biological control methods have now attracted high interest. In this note, we report for the first time the predationof the Red Palm Weevil by two subspecies of Southern Grey Shrike Lanius meridionalis, once in Spain and once in SaudiArabia
Morphological diversity among local and introduced maize (Zea mays L.) varieties in Haiti for yield improvement
Get PDFMaize, the cereal with the largest production in the world, is a staple crop in many developing countries includingHaiti. Even if Haiti is the second maize consumer in the Caribbean region, its national yield is low and alleged ofaflatoxin contamination. In order to increase grain yield, three introduced and two local maize varieties (theseused as comparative control) were evaluated. Three field trials were carried out at Torbeck and Morne Briller (Port-Salut) during different growing seasons. Experiments were designed in a three-replicate randomized block. Eachexperimental plot was 3.50 m per 10.5 m with a gross area of 36.75 m2 and 40 000 plants/ha densities. The trialswere carried out according to local agricultural practices. The results revealed that the introduced varieties hada smaller yield than the local ones. Moreover, all varieties showed some aflatoxin content below the EuropeanUnion limit (5μg/Kg). Statistical analyses showed a strong and direct correlation between yield and ear weightand an inverse correlation between yield and male and female flowering day after sowing. The broad phenotypicdiversity suggested a rich reserve of alleles to exploit in a breeding program focused to improve food security inHaiti
Shortening of generation cycles in inbred lines of maize (Zea mays L.) through embryo rescue technique
Get PDFEmbryo rescue techniques have been used as an approach to raise hybrids from incompatible crosses. Thesetechniques have also proved to be valuable tools for maize improvement, since they allow reducing the durationof the generation cycles for speed breeding. The aim of this study was to identify an efficient embryo rescueprotocol to evaluate the response of maize (Zea mays L.) embryo culture and compare its generation time (seedto seed) with the generation time of plants obtained by mature seed germination. To this purpose, we evaluatedthe germination efficiency, in vitro protocol efficiency, and days to flowering of three advanced maize inbred linesdeveloped at the National Institute of Agricultural Technology of Argentina. A greenhouse traditional strategywas used as control. The embryo rescue technique allowed obtaining nearly four generations per year comparedto the two generations obtained in greenhouse. All the plants obtained by the embryo rescue technique weremorphologically normal and fertile. The results confirmed the possibility of using embryo rescue strategies tosignificantly reduce the duration of the generation cycles in maize
Canopy gaps characteristics of pure and mixed stands in the Hyrcanian forests of north Iran
Get PDFCanopy gaps play an important role in forest ecology helping to preserve biodiversity, influence nutrient cycles, maintain the complex stand structure, and also they substantially contribute to regeneration of forests. To survey the characteristics of canopy gaps in the Hyrcanian forests of Iran, three main old-growth and intact stands were studied. For each canopy gap, two parameters were measured: the length (L) as the longest distance within the gap and the width (W) as the largest distance perpendicular to the length. The gap maker (DBH≥20 cm) was considered to be a tree from the upper tree layer whose death caused an opening in the canopy. A total of 89 canopy gaps were studied in three old-growth stands (48 gaps in hornbeam-ironwood, 21 in hornbeam, and 19 in beech-hornbeam stands). The given canopy gaps cover 5.4% of the land area with an average of eight gaps per hectare. The mean size of the canopy gaps were 291, 353 and 565m2 for hornbeam-ironwood, hornbeam, and beech-hornbeam stands, respectively. Frequency distribution of the gap sizes the mentioned three forest stands showed a lognormal distribution. The number of gap makers ranged from one to eight with a median of 4.5. Amongst the studied 261 gap makers in all canopy gaps, 61.2% belonged to hornbeam-ironwood stand. Also, there were canopy gaps formed by one to four gap makers within the three forest types, while gaps formed by five, six and eight gap makers were only observed within hornbeam stand. The results showed that the characteristics of the canopy gaps were different in terms of the composition, complexly of structure, environmental characteristics, size, number and species of gap makers in different forests. As a whole, hornbeam-ironwood stands present in lower altitudes, are more susceptible to wind-throw and create smaller gaps but more gap makers
DISCOVERY OFALLONYX QUADRIMACULATUS(SCHALLER, 1783)(COLEOPTERA CLERIDAECLERINAE) IN RUSSIA
Get PDFThe paper presents data on a record ofAllonyx quadrimaculatus(Schaller) in the Republic of Mordovia (Russia,CentralEuropeanTerritory) and also the whole known information about specimens of the species stored in Russianmuseums. Wediscussthespecies’ distribution which is considered as intermittent. Data on biology of Allonyxquadrimaculatusand description of its newly found habitat are presented
NEW RECORDS OF MOTHS ELUCIDATE THE IMPORTANCE OF FORESTSAS BIODIVERSITY HOT-SPOTS IN CENTRAL MEDITERRANEAN LANDSCAPES(LEPIDOPTERA)
Get PDFIn this paper we report new faunistic findings concerning 15 moth species collected in forested habitats ofCalabria and Sicily regions, South Italy. Most interesting records concerned Eupithecia trisignariaand Orectisproboscidata,both recorded for the first time in southern Italy. Species with larval biology linked to the forest coverwere locally common, whilst species linked to herbaceous plants and shrubs were often collected as singletons or in onelocality, showing smaller populations. A study of a 658bp long sequence of the mitochondrial 5’ cytochrome oxidasegene, subunit 1 (COI) (barcoding analysis) was performed for five species, two of them showing a divergence fromclosest populations near to 1%, one a 2% divergence from northern populations, and two other species a perfect identitywith European populations. This study reinforced the role of forest habitats as biodiversity hot-spots in theMediterranean Basin and the importance of the Italian peninsula for biodiversity conservation at European scale as anincreased number of endemic or sub-endemic taxa and populations with endemic genetic lineages are recognized,underlining the existence of ongoing evolutionary processes. In the light of these results, faunistic surveys in forestecosystems are strongly needed to define sustainable management strategies
ENVIRONMENTAL FACTORS IMPACT AND INCIDENCE OF PARASITISMOF PSYLLAEPHAGUS BLITEUSRIEK (HYMENOPTERA ENCYRTIDAE)ON POPULATIONS OF GLYCASPIS BRIMBLECOMBEIMOORE(HEMIPTERA APHALARIDAE) IN MEDITERRANEAN CLIMATIC AREAS
Get PDFThe red gum lerp psyllid, Glycaspis brimblecombeiMoore (Hemiptera, Aphalaridae), is an Australian native sap-sucking insect pest of eucalypts that has been first reported for the West Palaearctic Region in 2008 and, in 2010, it hasbeen found also in Italy. Subsequently its primary parasitoid, Psyllaephagus bliteus Riek (Hymenoptera: Encyrtidae),was also detected within the main European and North African infested areas, where no release of the parasitoid was everperformed. This study, carried out in 30 Eucalyptus camaldulensis plantations located along the coast, on the hills andthe mountains in Mediterranean climatic areas of Sicily (Italy), aimed to determine the influence of environmentalparameters on the incidence of both, the psyllid infestation level and the parasitization activity. P. bliteusreached high-est average levels in summer samplings and resulted widespread in Sicily at all detected altitudes without statisticallysignificant differences. P. bliteus parasitization is the main factor lowering G. brimblecombei infestation; this result,together with the accidental and contemporaneous arrival of the host and its parasitoid, could explain the absence of highdamage level on eucalypts in Sicily. The most significant metric factors positively influencing G. brimblecombei infes-tation are the percentage of daily hours above 80% of relative humidity and the average maximum temperature, obvi-ously related to other, but less significant climatic factors. The altitude affects both infestation and parasitization, but sin-gle sites could explain significantly more, so that the local conditions where the samplings were carried out have to beconsidered as the main responsibles for the variability in the obtained results. In any sampled Sicilian site, from sea levelto 540 m a.s.l., both the psyllid and its parasitoids show a good adaptation to climatic conditions, confirming that areasfitting for E. camaldulensisgrowth fit also for P. bliteus activity, and proving that Mediterranean climate, differently fromsome inland areas of California, does not obstacle its parasitic activity