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da Silva P.H.M.,Institute Pesquisas e Estudos Florestais IPEF | Sebbenn A.M.,University of Sao Paulo | Sebbenn A.M.,Sao Paulo State University | Grattapaglia D.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuaria | Grattapaglia D.,Catholic University of Brasilia
Forest Ecology and Management | Year: 2015

We investigated the rate of pollen-mediated flow and realized reproductive success at increasing distances from the source, across fragmented clonal stands of hybrid eucalypts in Brazil by parentage analysis of grown out seedlings using genetic data at 15 microsatellite markers. Two study areas were employed: a pollen donor area composed of a clonal stand of a single pollen donor clone (PD) and a pollen sink (PS) area composed of a mixed clonal stand of two other clones (PS1 and PS2). In the pollen sink area four plots with 30 trees each, located at 25, 200, 400 and 550. m from the PD were established as sink islands. Before flowering, the entire clonal stands of clones PS1 and PS2, with exception of the sink islands were clear cut. Seeds were harvested from five randomly sampled trees in each sink island and the paternity of 15 seedlings per tree, 75 seedlings per island totaling a sample of 300 seedlings, was determined with PD as the alleged father. The self-pollination rate in the sink islands varied from zero to 24%. Paternity assignment to the PD was highest in the island at 25. m (17.3%) and rapidly decreased to 4.0% at 200. m and 2.7% at 550. m, suggesting a pattern of isolation by distance, while revealing a large pollen contribution from unaccounted sources across all islands. Our results in a fragmented clonal site agree with previous estimates of general pollen movement in eucalypt seed orchards, showing that pollination will take place by and large at relatively short distances of less than 200. m, consistent with the expected range of flight of pollinator bees. Nevertheless the exponential distribution observed also indicates that low levels of pollination success are to be expected over longer distances. Our data provide useful guidelines regarding the distance at which seed orchards should be established away from potentially large pollen pressure of clonal stands to minimize unwanted pollen introgression. Furthermore, our results on dispersal rate and distance of pollen have direct implications on gene containment strategies and modeling studies, as pollen-mediated gene flow is one of the key determinants of the potential ecological and biosafety impacts of prospective transgenic eucalypts. © 2014 Elsevier B.V. Source


Da Silva P.H.M.,Institute Pesquisas e Estudos Florestais IPEF | Poggiani F.,University of Sao Paulo | Sebbenn A.M.,Instituto Florestal Of Sao Paulo If | Mori E.S.,Sao Paulo State University
Forest Ecology and Management | Year: 2011

Some Eucalyptus species are widely used as a plantation crop in tropical and subtropical regions. One reason for this is the diversity of end uses, but the main reason is the high level of wood production obtained from commercial plantings. With the advancement of biotechnology it will be possible to expand the geographical area in which eucalypts can be used as commercial plantation crops, especially in regions with current climatic restrictions. Despite the popularity of eucalypts and their increasing range, questions still exist, in both traditional planting areas and in the new regions: Can eucalypts invade areas of native vegetation, causing damage to natural ecosystems biodiversity?The objective of this study it was to assess whether eucalypts can invade native vegetation fragments in proximity to commercial stands, and what factors promote this invasive growth. Thus, three experiments were established in forest fragments located in three different regions of Brazil. Each experiment was composed of 40 plots (1m 2 each one), 20 plots located at the border between the forest fragment and eucalypts plantation, and 20 plots in the interior of the forest fragments. In each experimental site, the plots were paired by two soil exposure conditions, 10 plots in natural conditions and 10 plots with soil exposure (no plant and no litter). During the rainy season, 2g of eucalypts seeds were sown in each plot, including Eucalyptus grandis or a hybrid of E. urophylla×E. grandis, the most common commercial eucalypt species planted in the three region. At 15, 30, 45, 90, 180, 270 and 360 days after sowing, we assessed the number of seedlings of eucalypts and the number of seedlings of native species resulting from natural regeneration. Fifteen days after sowing, the greatest number of eucalypts seedlings (37m -2) was observed in the plots with lower luminosity and exposed soil. Also, for native species, it was observed that exposed soil improved natural germination reaching the highest number of 163 seedlings per square meter. Site and soil exposure were the factors that have the greatest influence on seed germination of both eucalypt and native species. However, 270 days after sowing, eucalypt seedlings were not observed at any of the three experimental sites. The result shows the inability of eucalypts to adapt to condition outside of their natural range. However, native species demonstrated their strong capacity for natural regeneration in forest fragments under the same conditions where eucalypts were seeded. © 2011 Elsevier B.V. Source


Silva P.H.M.D.,Institute Pesquisas e Estudos Florestais IPEF | Sebbenn A.M.,University of Sao Paulo | Sebbenn A.M.,Sao Paulo State University | Grattapaglia D.,EMBRAPA - Empresa Brasileira de Pesquisa Agropecuaria | Grattapaglia D.,Graduate Program In Genomic Science Biotechnology And University Cato Lica Of Brasi Lia
Forest Ecology and Management | Year: 2014

We investigated the rate of pollen-mediated flow and realized reproductive success at increasing distances from the source, across fragmented clonal stands of hybrid eucalypts in Brazil by parentage analysis of grown out seedlings using genetic data at 15 microsatellite markers. Two study areas were employed: a pollen donor area composed of a clonal stand of a single pollen donor clone (PD) and a pollen sink (PS) area composed of a mixed clonal stand of two other clones (PS1 and PS2). In the pollen sink area four plots with 30 trees each, located at 25, 200, 400 and 550. m from the PD were established as sink islands. Before flowering, the entire clonal stands of clones PS1 and PS2, with exception of the sink islands were clear cut. Seeds were harvested from five randomly sampled trees in each sink island and the paternity of 15 seedlings per tree, 75 seedlings per island totaling a sample of 300 seedlings, was determined with PD as the alleged father. The self-pollination rate in the sink islands varied from zero to 24%. Paternity assignment to the PD was highest in the island at 25. m (17.3%) and rapidly decreased to 4.0% at 200. m and 2.7% at 550. m, suggesting a pattern of isolation by distance, while revealing a large pollen contribution from unaccounted sources across all islands. Our results in a fragmented clonal site agree with previous estimates of general pollen movement in eucalypt seed orchards, showing that pollination will take place by and large at relatively short distances of less than 200. m, consistent with the expected range of flight of pollinator bees. Nevertheless the exponential distribution observed also indicates that low levels of pollination success are to be expected over longer distances. Our data provide useful guidelines regarding the distance at which seed orchards should be established away from potentially large pollen pressure of clonal stands to minimize unwanted pollen introgression. Furthermore, our results on dispersal rate and distance of pollen have direct implications on gene containment strategies and modeling studies, as pollen-mediated gene flow is one of the key determinants of the potential ecological and biosafety impacts of prospective transgenic eucalypts. © 2014 Elsevier B.V. Source


Goncalves J.L.D.M.,University of Sao Paulo | Alvares C.A.,Institute Pesquisas e Estudos Florestais IPEF | Higa A.R.,Federal University of Parana | Silva L.D.,University of Sao Paulo | And 14 more authors.
Forest Ecology and Management | Year: 2013

Organized forestry in Brazil began in the late 1960s, stimulated by a government policy which subsidized afforestation programs from 1967 to 1989 to develop an internationally-competitive wood-based industry, managed by the private sector. Currently, planted forests in Brazil total about 6.9million ha, from which 4.9million ha is planted with eucalypt (around 25% of world plantation), 1.6million ha with pine, and 0.42Mha with other species. Roundwood consumption of forest plantations totaled 170.1millionm3 in 2011, eucalypt plantation accounted for 80.6% of this total.Most eucalypt plantations are managed in short rotations (6-8years) and are established in regions with water, nutritional and frost stresses of low to high degrees. The mean annual increment is 40m3ha-1year-1 roundwood, ranging from 25 to 60m3ha-1year-1 depending on the level of environmental stress. Improving natural resources use efficiency by breeding and matching genotypes to sites and using appropriate site management practices is a key challenge to sustain or increase productivity.The wide range of eucalypt species and hybrids with different climatic and edaphic suitability associated with the easy propagation by seeds and cloning allow the adaptation of plantations to various tropical and subtropical regions in Brazil. The possibility of using eucalypt wood in a range of purposes has led large and small enterprises to establish eucalypt forests for multiple uses. The desirable characteristics in association with the accumulated knowledge on eucalypt silviculture encourage the use of this genus in most plantations. The most important factors in the selective process for a genotype are wood characteristics, productivity level, susceptibility to pests and diseases, drought tolerance, especially in tropical regions (frost free), and frost tolerance in subtropical regions (mostly without water deficit). In regions with pronounced seasonality and moderate to long drought periods, the planting of hybrid genotypes predominates, propagated by cloning. Under subtropical conditions, the planting of single species predominates, propagated by seed. Clonal plantations with interspecific hybrids have been fundamental for eucalypt adaptation in regions under water and nutritional stresses. Given the rapid advances in eucalypt breeding, regarding adaptation to water stress and resistance to diseases and pests, and the adoption of clonal propagation techniques, genotypes are rapidly becoming obsolete and are replaced by more productive ones after harvesting. Thus, the replanting of crops has become a common procedure after the second half of the 1990s in Brazil.This paper describes the basic requirements for integrating genetic and silvicultural strategies to minimize abiotic and biotic constraints in eucalypt plantations. © 2013 Elsevier B.V. Source


De Barros Ferraz S.F.,University of Sao Paulo | Pereira M.F.,Claro | De Paula F.R.,Claro | Vettorazzi C.A.,University of Sao Paulo | Alvares C.A.,Institute Pesquisas e Estudos Florestais IPEF
Scientia Forestalis/Forest Sciences | Year: 2013

In São Paulo state, deforestation and agriculture activities are increasing soil losses processes, especially in areas of susceptible soils where soil conservation practices are not adopted. Environmental adequacy at property level regarding Permanent Protection Areas and Legal Reserves is considered a potential factor for reducing soil losses and it was based on this fact that we assessed soil losses of different scenarios of environmental adequacy. Simulations of erosive processes were carried out in 15 catchments of the Corumbataí river basin, with different forest restoration scenarios, as well as the current situation of land use/ land cover. The scenarios include reforestation of Permanent Preservation Areas (PPA); the reforestation hydrological sensitive areas; and two scenarios, the Legal Reserve installation in 20% of each catchment, being one of them for most critical areas in terms of erosion and the other at random. It was observed that the establishment of PPA and the reforestation of hydrological sensitive areas (HSA), offered a small contribution to the control of the erosive process, resulting in a reduction of 10% and 7.4%, respectively, while the legal reserve in critical areas has the significant reduction of 69.8%. The random scenario, in turn, resulted in a reduction of 21.4% of erosion. Results show that reforestation can reduce soil losses, but previous studies of land prioritization and planning could significantly increase its efficiency. Source

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