ABOVEGROUND AND BELOWGROUND BIOMASS AND CARBON ESTIMATES FOR CLONAL EUCALYPTUS TREES IN SOUTHEAST BRAZIL

Eucalyptus plantations represent a short term and cost efficient alternative for sequestrating carbon dioxide from the atmosphere. Despite the known potential of forest plantations of fast growing species to store carbon in the biomass, there are relatively few studies including precise estimates of the amount of carbon in these plantations. In this study it was determined the carbon content in the stems, branches, leaves and roots of a clonal Eucalyptus grandis plantation in the Southeast of Brazil. We developed allometric equations to estimate the total amount of carbon and total biomass, and produced an estimate of the carbon stock in the stand level. Altogether, 23 sample trees were selected for aboveground biomass assessment. The roots of 9 of the 23 sampled trees were partially excavated to assess the belowground biomass at a singletree level. Two models with DBH, H and DBH2H were tested. The average relative share of carbon content in the stem, branch, leaf and root compartments was 44.6%, 43.0%, 46.1% and 37.8%, respectively, which is smaller than the generic value commonly used (50%). The best-fit allometric equations to estimate the total amount of carbon and total biomass had DBH2H as independent variable. The root-to-shoot ratio was relatively stable (C.V. = 27.5%) probably because the sub-sample was composed of clones. Total stand carbon stock in the Eucalyptus plantation was estimated to be 73.38 MgC ha-1, which is within the carbon stock range for Eucalyptus plantations.

STRUCTURAL LEAF CHANGES IN TREES AROUND A SUBWAY AIR DUCT

ABSTRACTWhile a number of papers have shown that subway systems have an impact on the air quality through the release of particulate matters, no information about the impact of such particles on tree attributes is available. Tree leaves from three different species from the exit side of a subway station in Rio de Janeiro, Brazil, were more asymmetrical than leaves from the entrance side. This leaves also presenting changes in leaves cuticle and chlorophyll content.

ALLOMETRIC MODELS FOR ESTIMATING ABOVEGROUND BIOMASS AND BIOMASS ALLOCATION OF CAPIXINGUI TREES (Croton floribundus Spreng.) IN AN AGRISILVICULTURAL SYSTEM

ABSTRACT The objective of this study was to select allometric models to estimate total and pooled aboveground biomass of 4.5-year-old capixingui trees established in an agrisilvicultural system. Aboveground biomass distribution of capixingui was also evaluated. Single- (diameter at breast height [DBH] or crown diameter or stem diameter as the independent variable) and double-entry (DBH or crown diameter or stem diameter and total height as independent variables) models were studied. The estimated total biomass was 17.3 t.ha-1, corresponding to 86.6 kg per tree. All models showed a good fit to the data (R2ad > 0.85) for bole, branches, and total biomass. DBH-based models presented the best residual distribution. Model lnW = b0 + b1* lnDBH can be recommended for aboveground biomass estimation. Lower coefficients were obtained for leaves (R2ad > 82%). Biomass distribution followed the order: bole>branches>leaves. Bole biomass percentage decreased with increasing DBH of the trees, whereas branch biomass increased.

RELATIONSHIP BETWEEN CLIMATE VARIABLES, TRUNK GROWTH RATE AND WOOD DENSITY OF Eucalyptus grandis W. Mill ex Maiden TREES

ABSTRACT Climatic conditions stimulates the cambial activity of plants, and cause significant changes in trunk diameter growth and wood characteristics. The objective of this study was to evaluate the influence of climate variables in the diameter growth rate of the stem and the wood density of Eucalyptus grandis trees in different classes of the basal area. A total of 25 Eucalyptus trees at 22 months of age were selected according to the basal area distribution. Dendrometer bands were installed at the height of 1.30 meters (DBH) to monitor the diameter growth every 14 days, for 26 months. After measuring growth, the trees were felled and wood discs were removed at the DBH level to determine the radial density profile through x-ray microdensitometry and then re-scale the average values every 14 days. Climatic variables for the monitoring period were obtained and grouped every 14 days. The effect of the climate variables was determined by maximum and minimum growth periods in assessing trunk growth. These growth periods were related with precipitation, average temperature and relative air humidity. The re-scaled wood density values, calculated using the radial growth of the tree trunks measured accurately with steel dendrometers, enabled the determination of the relationship of small changes in wood density and the effect of the climatic variations and growth rate of eucalyptus tree trunks. A high sensitivity of the wood density to variation in precipitation levels was found.

Response of young 'Tahiti' lime trees to different irrigation levels

The aim of this study was to evaluate the effect of different irrigation levels on canopy and root growth, productivity, and fruit quality of young ‘Tahiti’ acid lime trees. The experiment was installed in Piracicaba, Brazil in a 1.0-ha orchard plot with ‘Tahiti’ acid lime trees, grafted on ‘Swingle’ citrumelo rootstock and carried out from August of 2002 to May 2005. Each treatment was assigned to a drip irrigation level, based on ETc as follows: T1) non-irrigated, T2) 25%, T3) 50%, T4) 75% and T5) 100% of ETc determined by weighing lysimeter presented in the orchard plot. Trunk diameter and tree height were evaluated monthly. The roots were evaluated when the trees were 30 and 48 months old. The yield and fruit quality was evaluated in 2004 and 2005. The results showed that irrigation did not influence root distribution in depth, and trees irrigated with 75% and 100% ETc showed horizontal root distribution concentrated until 0.6 m from the trunk. Irrigation did not improve the quality of fruit. Yield increased in all irrigated treatment, but the most efficient yield mean per unit of water applied was the 25% ETc treatment.

Spatial variability of yield and other parameters associated with pear trees

In the last few years, precision agriculture has become commonly used with many crops, particularly cereals, and there is also interest in precision horticulture. Pear is a seasonal fruit and well appreciated by Brazilian people, although it is mostly imported. Brazilian farmers are nowadays trying to increase pear production. Thus, this research aimed at mapping the yield of pear trees in order to study the spatial variability of yield as well as its comparison with spatial variability of soil and plant attributes. The experimental field had 146 pear trees, variety 'Pêra d'água', distributed on a 1.24 ha. Four harvests were performed according to the fruit ripening and from each tree; only the ripe fruits were harvested. In each harvest, all the fruits were weighed and the total yield was obtained based on the sum of each harvest. The soil attributes analyzed were P, K, Ca, Mg, pH in CaCl2, C, Cu, Zn, Fe, Mn and base saturation, and the plant attributes were fruit length, diameter and yield. Yield had low correlation with soil and plant attributes. An index of spatial variability was suggested in this study and helped in classifying levels of spatial dependence of the various soil and plant attributes: very low (fruit length); low (P, fruit diameter), medium (Mg, pH, Cu, Zn, Fe), high (Ca, K, base saturation and yield), and very high (Mn and C).

Water storage in wetted strips under irrigated coffee trees with different criteria of irrigation management

The increasing demand for water resources accentuates the need to reduce water waste through a more appropriate irrigation management. In the particular case of irrigated coffee planting, which in recent years presented growth with the predominance of drip irrigation, the improvement of drip irrigation management techniques is a necessity. The proper management of drip irrigation depends on the knowledge of the spatial pattern of soil moisture distribution inside the wetted strip formed under the irrigation lines. In this study, grids of 24 tensiometers were used to determine the water storage within the wetted strip formed under drippers, with a 3.78 L h-1 discharge, evenly spaced by 0.4 m, subjected to two different management criteria (fixed irrigation interval and 60 kPa tension). Estimates of storage based on a one-dimensional analysis, that only considers depth variations, were compared with two-dimensional estimates. The results indicate that for high-frequency irrigation the one-dimensional analysis is not appropriate. However, under less frequent irrigation, the two-dimensional analysis is dispensable, being the one-dimensional sufficient for calculating the water volume stored in the wetted strip.

Water requirement and yield of fig trees under different drip irrigation management

This work aimed to study the effect of drip irrigation management on growth and yield of the 'Roxo de Valinhos' fig tree (Ficus carica L.), at three years old, and to determine crop coefficients (Kc) and its water requirement (ETc) under Baixada Fluminense climate and soil conditions, state of Rio de Janeiro, Brazil. The study was carried out in the experimental area of SIPA (Sistema Integrado de Produção Agroecológica) in Seropédica, Rio de Janeiro State, from July 2011 to May 2012. The experimental area was divided in two blocks, named B1 (sandy clay loam texture) and B2 (loamy sand texture). In each block, irrigation frequencies (IF) of two (T1) and four days (T2) were evaluated, as well as the irrigation absence (T3). Irrigation management and water consumption determination were performed through the soil water balance, using the TDR technique. Plant growth was not affected by IF, differing only in the number of produced internodes. For both soil textures, the mean Kc was 0.60, with a significant difference (p<0.05) only for IF. The estimated mean yield showed no significant differences between both textural classes, ranging from 6,612 kg ha-1 (T3) to 8,554 kg ha-1 (T1). This study indicates the importance of irrigation frequency in the irrigation management of fig trees cultivated in soils with different physical characteristics.

Seed bank from soil of coffee plantations associated with grevillea trees

This study aimed to study the composition and dynamics of seed bank from soil of coffee plantations associated with grevilea trees in the experimental fields of the Southwest Bahia State University, on Vitória da Conquista campus. The experiments were carried out from September 2006 to May 2007. The coffee trees (Coffea arabica) were sown at three x one m spacing, associated with grevillea trees (Grevillea robusta) and maintained at densities of 277, 139, 123, 69, 62 and 31 plants ha-1, under direct sunlight. One hundred grams of soil were taken from each treatment with four repetitions and later identified and counted with a 10x magnifying glass. To determine seedling emergence, four soil samples of 1000 g were collected from each experimental field and transported to the greenhouse. Seedling emergence was observed by counts after 15, 30 and 45 days. The experimental design was randomized blocks of seven treatments (soil from different tree densities) and four replicates; the experimental unit consisted of a plastic tray (0, 30 x 0.22 x 0.06 m) containing 1.000 g of soil. The variables utilized to characterize the bank and its dynamics were: relative frequency, relative density, relative abundance, importance index and species diversity (Shannon-Weaver index).Increased number of monocotyledon seeds and sprouts were verified in the treatments maintained under full sunlight.

Weed community and growth under the canopy of trees adapted to the brazilian semi-arid region

The objectives of this work were to evaluate the floristic composition and dry biomass of weeds under the canopy of seven perennial species adapted to the Semi-Arid region of Brazil, and correlate these characteristics with growth traits of the perennial species. The following perennial species were evaluated in two experiments (E1 and E2): mesquite (Prosopis juliflora), jucá (Caesalpinia ferrea), white popinac (Leucaena leucocephala), mofumbo (Combretum leprosum), neem (Azadirachata indica), sabiá (Mimosa caesalpiniaefolia) and tamarind (Tamarindus indica). In E1, the seven species were evaluated in a random block design with four replicates and nine plants per plot. In E2, evaluation comprised four species (mesquite, jucá, white popinac, and tamarind) in a random block design with eight replicates and nine plants per plot. A circle with an area of 1.77 m² was established around the trunk of each plant, two years after they were transplanted to the permanent location. The weeds collected within this circle were cut even with the ground, classified and weighed. At this time, plant height, and crown and stem diameters were evaluated in all trees of each plot. In E1 there were no differences between tree species as to weed frequency under their canopies; however, weed growth was smaller under the canopy of sabiá trees. Mesquite and sabiá had the greatest plant height and crown diameter means, but only sabiá had the greatest stem diameter. In E2, the perennial species were not different with regard to weed frequency and growth under their canopies, but mesquite had the greatest growth, as measured by plant height (with significant results for jucá as well) and crown and stem diameter.

Temporal and spatial variations in the structure of macroalgal communities associated with mangrove trees of Ilha do Cardoso, São Paulo state, Brazil

Temporal and spatial variations in species composition and vertical distribution of macroalgal communities growing on mangrove trees were analyzed bimonthly in the Ilha do Cardoso State Park, São Paulo state (25°03'S and 47°55'W), Southeastern Brazil. The macroalgal communities from mangroves of Perequê and Sítio Grande rivers comprised 10 and 18 taxa respectively. Bostrychia radicans (Mont.) Mont. and B. calliptera (Mont.) Mont. were the predominant taxa, present almost throughout the year and in all the sites studied. The species composition of macroalgal communities from both mangroves presented temporal and spatial variations related to environmental factors. The highest number of taxa was observed during colder, drier months, coinciding with the highest means of high water neap and short periods of continuous emersion (April to August). Some mangrove algae such as B. calliptera, Rhizoclonium spp., Caloglossa spp., and Boodleopsis pusilla (Collins) W. Taylor, Joly et Bernatowicz showed a high degree of tolerance to desiccation, being able to tolerate continuous emersion up to six days. The spatial variations in species composition were related to light, as observed in Catenella caespitosa (Withering) L. Irvine, which occurred in well-lit sites. No pattern of vertical zonation was observed, since Rhizoclonium spp., B. radicans, and B. calliptera occur over the entire vertical range. Variations in the range of vertical distribution of macroalgae of Perequê mangrove were mainly related to the variations in the tidal levels (mean high water neap and/or mean high water spring) while those observed in Sítio Grande mangrove were related to salinity variations, except for B. calliptera and Caloglossa spp. related to tidal levels and high irradiance, respectively.

Chlorophyll fluorescence parameters in populations of two legume trees: Stryphnodendron adstringens (Mart.) Coville (Mimosoideae) and Cassia ferruginea (Schrad.) Schrad. ex DC. (Caesalpinoideae)

The aim of this study was to investigate the photosynthetic performance in populations of two legume tree species, Stryphnodendron adstringens (Mimosoideae), typical from Cerrado, and Cassia ferruginea (Caesalpinoideae) from the Atlantic Rain Forest. The photosynthetic traits were assessed by measures of chlorophyll fluorescence in progenies of naturally pollinated plants from three populations of S. adstringens and a population of C. ferruginea. Plants of S. adstringens growing under similar conditions of C. ferruginea plants demanded higher light values for photosynthesis saturation, 600 µmol.m-2.s-1 and 350 µmol.m-2.s-1 respectively, and showed higher intrinsic photosynthetic efficiency of photosystem II, Fv/Fm of 0.814 versus 0.783 in C. ferruginea. The highest values of Fv/Fm observed in S. adstringens can explain the highest electron transport rates (ETR) obtained for this species. No significant differences were found among progenies from different C. ferruginea trees nor among populations of S. adstringens, and only in few cases, variation among progenies within populations were found for S. adstringens plants. The fact that fluorescence parameters distinguished species but not populations or most of progenies may be related to low intraspecific genetic variation of these chlorophyll fluorescence traits or due to lack of expression on genetic differences in plants under no stressful conditions.

Juvenile dynamics of the endemic and rare Enterolobium glaziovii Benth. (Mimosaceae) around reproductive trees in the Atlantic forest, Brazil

Studies on the regeneration and seedling mortality of rare tree species are important, but scarce. The aim of this study was to investigate the annual variation in recruitment, growth and mortality of juveniles of Enterolobium glaziovii Benth., a rare tree species from the Brazilian Atlantic Rain Forest. All seedlings and juveniles around four reproductive trees were labeled and their fate was followed from 1996 to 1999. There were no annual differences in juveniles' recruitment below and beyond the parental crown, but juveniles' survival and growth were lower below than beyond of the parental tree crowns. Small individuals (< 15 cm tall) showed the greatest mortality and the lowest growth, followed by medium (from 15 to 50 cm tall) and large ones (> 50 cm tall). Large juveniles were more widely dispersed from the conspecific parental tree than were medium and small ones. This suggests that distance dependent mortality of juveniles mediated by the parental tree is an important cause of spacing shifts associated with the growth of small individuals of E. glaziovii into large ones. Widely dispersed juveniles may escape the high mortality associated with pathogens, herbivores or seed predators concentrated around adult conspecifics. The negative influence of the parental tree on its juveniles may explain the sparse distribution of its adults in the forest.

Identification of volatile compounds in thinning discards from plum trees (Prunus salicina Lindl.) cultivar Harry Pickstone

Plum (Prunus salicina Lindl. cv. Harry Pickstone), a China indigenous fruit, is widely produced and consumed in countries such as Japan and Brazil. The practice of thinning is common in horticulture and the fruits removed are discarded as waste. Like the great majority of vegetables, these thinning discards also contain essential oils which have not been investigated until the present time. The extraction of the plum thinning discards volatile oil, through the hydrodistillation method, produced a yield of 0.06% (m/m) and a total of 21 components were identified, with 11 of them being responsible for 72,9% of the total oil composition. The major compounds determined through GC and GC-MS were Z-α-bisabolene (13.7%), n-hexadecanoic acid (12.7%), phytol (12.7%), and β-caryophyllene (10.4%).

Characterization and classification of pequi trees (Caryocar brasiliense Camb.) based on the profile of volatile constituents using headspace solid-phase microextraction - gas chromatography - mass spectrometry and multivariate analysis

In order to determine the variability of pequi tree (Caryocar brasiliense Camb.) populations, volatile compounds from fruits of eighteen trees representing five populations were extracted by headspace solid-phase microextraction and analyzed by gas chromatography-mass spectrometry. Seventy-seven compounds were identified, including esters, hydrocarbons, terpenoids, ketones, lactones, and alcohols. Several compounds had not been previously reported in the pequi fruit. The amount of total volatile compounds and the individual compound contents varied between plants. The volatile profile enabled the differentiation of all of the eighteen plants, indicating that there is a characteristic profile in terms of their origin. The use of Principal Component Analysis and Cluster Analysis enabled the establishment of markers (dendrolasin, ethyl octanoate, ethyl 2-octenoate and β-cis-ocimene) that discriminated among the pequi trees. According to the Cluster Analysis, the plants were classified into three main clusters, and four other plants showed a tendency to isolation. The results from multivariate analysis did not always group plants from the same population together, indicating that there is greater variability within the populations than between pequi tree populations.