The objectives of the study were to assess changes in fine root anisotropy and specific root lengths throughout the development of Eucalyptus grandis (W. Hill ex Maiden) plantations and to establish a predictive model of root length density (RLD) from root intercept counts on trench walls. Fine root densities (<1 mm in diameter) were studied in 6-, 12-, 22-, 28-, 54-, 68-and 72-month-old E. grandis plantations established on deep Ferralsols in southern Brazil. Fine root intercepts were counted on 3 faces of 90-198 soil cubes (1 dm 3 in volume) in each stand and fine root lengths (L) were measured inside 576 soil cubes, sampled between the depths of 10 cm and 290 cm. The number of fine root intercepts was counted on one vertical face perpendicular to the planting row (N t ), one vertical face parallel to the planting row (N l ) and one horizontal face (N h ), for each soil cube sampled. An overall isotropy of fine roots was shown by paired Student's t-tests between the numbers of fine roots intersecting each face of soil cubes at most stand ages and soil depths. Specific root lengths decreased with stand age in the upper soil layers and tended to increase Plant Soil (2010) 334:261-275 in deep soil layers at the end of the rotation. A linear regression established between N t and L for all the soil cubes sampled accounted for 36% of the variability of L. Such a regression computed for mean N t and L values at each sampling depth and stand age explained only 55% of the variability, as a result of large differences in the relationship between L and N t depending on stand productivity. The equation RLD= 1.89*LAI*N t , where LAI was the stand leaf area index (m 2 m −2 ) and N t was expressed as the number of root intercepts per cm 2 , made it possible to predict accurately (R 2 =0.84) and without bias the mean RLDs (cm cm −3 ) per depth in each stand, for the whole data set of 576 soil cubes sampled between 2 years of age and the end of the rotation.

Restoration of Atlantic Forests is receiving increasing attention because of its role in both biodiversity conservation and carbon sequestration for global climate change mitigation. This study was carried out in an Atlantic Forest restoration project in the south-central region of Sã o Paulo State --Brazil to develop allometric equations to estimate tree biomass of indigenous tree species in mixed plantations. Above and below-ground biomass (AGB and BGB, respectively), stem diameter (DBH: diameter at 1.3 m height), tree height (H: total height) and specific wood density (WD) were measured for 60 trees of 19 species. Different biomass equations (linear and nonlinear-transformed) were adjusted to estimate AGB and BGB as a function of DBH, H and WD. For estimating AGB and BGB, the linear biomass equation models were the least accurate. The transformed nonlinear biomass equation that used log DBH 2 , log H and log WD as predictor variables were the most accurate for AGB and the transformed nonlinear biomass equations that used log DBH 2 *WD as predictor variables were the most accurate for BGB. It is concluded that these adjusted equations can be used to estimate the AGB and BGB in areas of the studied project. The adjusted equations can be recommended for use elsewhere in the region for forest stands of similar age, tree size ranges, species composition and site characteristics. Keywords: Above-ground biomass, Below-ground biomass, Biomass equation, Tree allometry, Atlantic Forest, Restoration.NOGUEIRA JUNIOR, L.R., ENGEL, V.L., PARROTTA, J.A., MELO, A.C.G., RÉ , D.S. Equações alométricas para estimativa da biomassa arbórea em plantios mistos com espécies nativas na restauração da Mata Atlântica.http://dx.doi.org/10.1590/1676-06032013008413Resumo: A restauraçã o da Mata Atlâ ntica vem recebendo aumento na atençã o por causa do papel na conservaçã o da biodiversidade e sequestro de carbono para a mitigaçã o da mudança global do clima. Este estudo foi conduzido em um projeto de restauraçã o da Mata Atlâ ntica na regiã o centro-sul do Estado de Sã o Paulo --Brasil e buscou desenvolver equaçõ es alométricas para estimar a biomassa arbó rea de espécies nativas em plantios mistos. Em 60 á rvores de 19 espécies foram medidas a biomassa acima e abaixo do solo, o diâ metro do tronco (DAP: diâ metro a 1,3 m de altura), altura (H) e densidade específica da madeira (Ds). Diferentes equaçõ es de biomassa (linear e nã o linear) foram ajustadas para estimar a biomassa acima e abaixo do solo, utilizando DAP, H e Ds como variá veis preditoras. As equaçõ es de biomassa lineares foram as menos acuradas para a estimativa da biomassa acima e abaixo do solo. As equaçõ es de biomassa nã o lineares que usaram log DAP 2 , log H e log Ds como variá veis preditoras foram mais acuradas para a estimativa da biomassa acima do solo e as nã o lineares que usaram log DBH 2 *WD como variá veis preditoras foram as mais acuradas para a estimativa da biomassa abaixo do solo. Conclui-se que estas equaçõ es ajustadas podem ser usadas na estim...

RESUMO:Visando a suprir a lacuna do conhecimento existente sobre a estimação precisa do potencial de produção madeireira de sistemas de restauração florestal, com o presente trabalho, objetivou-se modelar as relações alométricas (hipsométricas e volumétricas) de nove espécies comuns a modelos alternativos de restauração da floresta estacional semidecidual. Os modelos se ajustaram bem aos dados coletados e a análise de resíduos indicou distribuição satisfatória, tanto para os modelos hipsométricos como volumétricos. O modelo hipsométricos de Stoeffels e o modelo volumétrico de Schumacher-Hall foram os mais flexíveis, ajustando melhor para várias espécies. Essas equações obtidas serão usadas em futuros estudos de manejo e conservação de áreas em restauração. TREE ALLOMETRIC EQUATIONS IN MIXED FOREST PLANTATIONS FOR THE RESTORATION OF SEASONAL SEMIDECIDUOUS FORESTABSTRACT: Aiming to overcome the lack of knowledge about precise estimation of wood production potential of forest restoration systems, the objective of this study is modeling allometric relationships of nine tree species in alternative models of seasonal semideciduous forest restoration. The models fitted well to the data with satisfactory distribution of the residuals. The height-diameter relationship was best modeled by the Stoeffles model and the volume equations had the best fit with the Schumacher-Hall model, for many species. The equations obtained will be used in future studies of management and conservation of these plantations.

Although livestock have been historically associated with land conversion and biodiversity loss, well‐managed cattle grazing has been reported to contribute to conservation of open ecosystems. Knowing the balance between positive and negative effects of livestock (presence or exclusion) on different ecosystems is, therefore, crucial to support management decisions. We conducted an experiment in a secondary savanna with exotic grasses, used as pasture, to assess the effect of cattle presence in low density and cattle exclusion (in paired plots) on the trajectory of these ecosystems. Richness, composition and structure of the woody community, and exotic grass cover and biomass were compared between treatments in the beginning of the experiment and after 7 years. At the end of the experiment, we also compared composition, richness, and density of the native ground layer. We verified that (a) cattle exclusion accelerates the undesirable woody encroachment, changes the species composition and leads to huge grass fuel accumulation, while (b) cattle grazing/browsing hinders changes in savanna structure and composition and reduces the exotic grass cover and biomass, thus favoring native herbaceous plants. By decreasing the grass biomass, cattle grazing also reduces the system flammability and, therefore, the risk and intensity of wildfires. Together, the positive effects of cattle presence and the negative effects of cattle exclusion lead to the conclusion that cattle should be maintained in these systems. Low‐intensity cattle grazing limits woody and exotic grass invasion, improves native forb biodiversity, and help to maintain composition and structural features of secondary savannas of the Cerrado. Abstract in Portuguese is available with online material