Tropical Forests and Climate Change Mitigation: The Global Potential and Cases from the Philippines

The Intergovernmental Panel on Climate Change IPCC Fourth Assessment report has highlighted the role of tropical forests in mitigating climate change. Deforestation, especially in tropical countries, contributes about 20 percent to total global greenhouse gas emissions. Development projects geared to reduce the rate of deforestation and forest degradation, and to establish forest plantations will help reduce greenhouse gases in the atmosphere, and significantly contribute to mitigating climate change. Three cases of forestry carbon projects underway in the Philippines are presented to illustrate the constraints facing project developers in undertaking these climate change mitigation efforts. Among the key lessons identified are: the difficulty in establishing land eligibility, the need for partners or buyers from industrialized countries to shoulder the transaction costs, and the crucial role of the local communities, including indigenous peoples, in the development effort.

Peculiar Bi-ion dynamics in Na1/2Bi1/2TiO3 from terahertz and microwave dielectric spectroscopy

Dynamics of the main dielectric anomaly in Na1/2Bi1/2TiO3 (NBT) was studied by time-domain THz and microwave spectroscopy, using also previously published data and their new overall fits. Above the dielectric maximum temperature Tm ~ 600 K, the response consists of coupled sub-THz oscillator and a relaxation mode, assigned to strongly anharmonic Bi-ion vibrations and hopping, whose slowing down explains the paraelectric-like permittivity increase to Tm. Below Tm, the main relaxation continues slowing down and additional relaxation, assigned to quasi-Debye losses, appears in the 10^11 Hz range. The oscillator hardens on cooling and takes over the whole oscillator strength. The permittivity decrease below Tm is caused by the reduced strength of the relaxations due to dominance of the rhombohedral phase within the coexistence region with the tetragonal phase. The anharmonic dynamics of Bi is supported by previous structural studies. NBT represents a hybrid between standard and relaxor ferroelectric behaviour

Philippine forest ecosystems and climate change: Carbon stocks, rate of sequestration and the Kyoto Protocol

ropical forests have a valuable role in relation to climate change, being a source and sink of carbon. This paper reviews the state of knowledge on carbon stocks and rate of sequestration of various forest ecosystems in the Philippines. Carbon density ranges widely from less than 5 t/ha to more than 200 t/ha in the following order: old growth forests > secondary forest > mossy forest > mangrove forest > pine forest > tree plantation > agroforestry farm > brushlands > grasslands. Carbon sequestration ranges from less than 1 t/ha/yr in natural forests to more than 15 t/ha/yr in some tree plantations. Land-use change and forestry make an important contribution in the national emissions and sinks. It is estimated that Philippine forest lands are a net sink of greenhouse gasses (GHG) absorbing 107 Mt CO2 equivalent in 1998, about equal to the total Philippine GHG emissions. The clean development mechanism (CDM) presents a clear opportunity for Philippine forestry, if the threats are properly addressed

Carbon Storage and Sequestration Potential of Smallholder Tree Farms on Leyte Island, the Philippines

The role of terrestrial ecosystem in mitigating the effects of climate change entails the assessment of carbon stocks in various pools. This study predicts the carbon storage and sequestration potential of common tree farm species in Leyte Island, the Philippines. Data gathered from field measurements has been used to fit the Chapman-Richards growth function to predict the volume and biomass increment of Gmelina arborea and Swietenia macrophylla tree farms until they reached their respective rotation ages. Biomass and carbon density values are found to vary with age, type of species, site conditions and silvicultural treatments applied in the stand. Although differences in year when the trees were planted had no relation with its soil carbon storage, this pool had greater storage capacity than the above-ground biomass and roots. The average maximum growth was attained after 10 years for G. arborea and 13 years for S. macrophylla. Volume growth started to slow down when the tree species reached almost half its rotation age. The same trend was observed for the biomass and carbon density of each farm. The maximum mean annual increment of both species was attained before the expected maximum growth year. Growth increment decreased as the species reached their rotation age. The total C storage capacity of a 15-year-old G. arborea tree farm was estimated at 64 MgC/ha while that of a 25-year-old S. macrophylla was estimated at 159 MgC/ha. The average carbon sequestration rate of both species was 5 MgC/ha/yr which is lower than the average rate of most tree plantation species in the Philippines. With almost 2 M ha of grasslands in the country, establishing tree farms is a strategy to attain the national goal on sustainable development and at the same time reduce the greenhouse gases (GHGs) emissions

Human cancers over express genes that are specific to a variety of normal human tissues

We have analyzed gene expression data from 3 different kinds of samples: normal human tissues, human cancer cell lines and leukemic cells from lymphoid and myeloid leukemia pediatric patients. We have searched for genes that are over expressed in human cancer and also show specific patterns of tissue-dependent expression in normal tissues. Using the expression data of the normal tissues we identified 4346 genes with a high variability of expression, and clustered these genes according to their relative expression level. Of 91 stable clusters obtained, 24 clusters included genes preferentially expressed either only in hematopoietic tissues or in hematopoietic and 1-2 other tissues; 28 clusters included genes preferentially expressed in various non-hematopoietic tissues such as neuronal, testis, liver, kidney, muscle, lung, pancreas and placenta. Analysis of the expression levels of these 2 groups of genes in the human cancer cell lines and leukemias, identified genes that were highly expressed in cancer cells but not in their normal counterparts, and were thus over expressed in the cancers. The different cancer cell lines and leukemias varied in the number and identity of these over expressed genes. The results indicate that many genes that are over expressed in human cancer cells are specific to a variety of normal tissues, including normal tissues other than those from which the cancer originated. It is suggested that this general property of cancer cells plays a major role in determining the behavior of the cancers, including their metastatic potential.Comment: To appear in PNA

Biomass Equations for Tropical Tree Plantation Species Using Secondary Data from the Philippines

Estimation of the magnitude of sinks and sources of carbon requires reliable estimates of the biomass of forests and of individual trees. Equations for predicting tree biomass have been developed using secondary data involving destructive sampling in plantations in several localities in the Philippines. These equations allow estimates of carbon sequestration to be made at much lower cost than would be incurred if detailed stand inventories were undertaken. The species included in the study reported here include Gmelina arborea, Paraserianthes falcataria, Swietenia macrophylla and Dipterocarp species in Mindanao; Leucaena leucocephala from Laguna, Antique, Cebu, Iloilo, Rizal, and Ilocos Sur, and Acacia mangium, Acacia auriculiformis and G. arborea in Leyte. Non-linear regression was used to derive species-specific, site-specific and generic equations between yield and diameter of the form y = aDb. Equations were evaluated based on the correlation coefficient, standard error of the estimate and residual plots. Regressions resulted to high r values (>0.90). In some cases, non-homogeneous variance was encountered. The generic equation improved estimates compared with models used in previous studies

Electric-field-temperature phase diagram of the ferroelectric relaxor system (1-x)Bi1/2Na1/2TiO3-xBaTiO3 doped with manganese

The electric-field-temperature phase diagram for the lead-free relaxor material (1 - x)(Bi1/2Na1/2)TiO3 - xBaTiO 3 (x = 0.03, 0.06, and 0.09) doped with 0.5 mol% Mn (BNT-100xBT:Mn) was established. Transition lines between ergodic or nonergodic relaxor states and the field-induced ferroelectric state were determined at constant temperatures with electric-field-dependent measurements of the polarization as well as of the piezoelectric coefficient and permittivity. Near the depolarization temperature Td, the switching between two ferroelectric poling directions occurs in two steps via an intermediate relaxor state. This effect is closely related to the pinching of the ferroelectric hysteresis loop.open2

Biomass equations for tropical tree plantation species in young stands using secondary data from the Philippines

Estimation of the magnitude of sinks and sources of carbon requires reliable estimates of the biomass of forests and of individual trees. Equations for predicting tree biomass have been developed using secondary data involving destructive sampling in plantations (mostly less than 10 years of age) in several localities in the Philippines. These equations allow estimates of carbon sequestration to be made at much lower cost than would be incurred if detailed stand inventories were undertaken. The species included in the study reported here include Gmelina arborea Roxb., Paraserianthes falcataria (L.) Nielsen Swietenia macrophylla King and Dipterocarp species in Mindanao, and Leucaena leucocephala de Wit from Laguna, Antique, Cebu, Iloilo, Rizal, and Ilocos Sur. Non-linear regression was used to derive species-specific, site-specific and generic equations between yield and diameter of the form y = D. Equations were evaluated based on the correlation coefficient, standard error of estimate and residual plots. Regressions resulted in high r values (>0.90). In some cases, non-homogeneous variance was encountered. The generic equation improved estimates compared with models used in previous studies

Nanoscale phase quantification in lead-free (Bi1/2Na1/2)TiO3-BaTiO3 relaxor ferroelectrics by means of Na 23 NMR

We address the unsolved question on the structure of relaxor ferroelectrics at the atomic level by characterizing lead-free piezoceramic solid solutions (100-x)(Bi1/2Na1/2)TiO3-xBaTiO3 (BNT-xBT) (for x=1,4,6, and 15). Based on the relative intensity between spectral components in quadrupolar perturbed Na23 nuclear magnetic resonance, we present direct evidence of the coexistence of cubic and polar local symmetries in these relaxor ferroelectrics. In addition, we demonstrate how the cubic phase vanishes whenever a ferroelectric state is induced, either by field cooling or changing the dopant amount, supporting the relation between this cubic phase and the relaxor state.open0