Leaf and branch biomass productivity of plant communities have been little studied in northern Mexico. Global warming concerns are prompting research dealing with biomass production and carbon sequestration by plant communities. Biomass components and productivity are key pieces of information for running several carbon models. In this research, we developed information on leaf and branch biomass productivity of sixteen different plant communities encompassing native pine, oak, shrub, and exotic pine forests. We established sampling plots, measured dasometric features of trees, and collected leaf and branch biomass for periods of 7 to 21 days during 2004 in Nuevo Leon, Mexico. Results indicate that leaf and branch productivity is on the average 3.70 Mg ha^-1 y^-1 (±0.98 Mg ha^-1 y^-1) with only two plant communities (intermittent riverine Tamaulipan matorral and upland planted Cupressus spp communities) surpassing 7 Mg ha^-1 y^-1. The exotic pine species (P. nelsoni, P. pinceana, and P. cembroides) planted in proceeding trials produced less than 3 Mg ha^-1 y^-1. The statistical analysis of this information showed large spatial and temporal variations. The former was explained by microsite and plant density. The last source of variation was partially dependent on climate fluctuations and the natural annual productivity cycle. Further research is required to understand the fate of leaf and branch on soils.

Reforestation is an important mean to protect soils, to restore habitat for plants and animals, to regulate the hydrological cycle, to recharge aquifers, to produce oxygen and to sequester carbon dioxide. Global warming concerns are prompting reforestation practices and studies dealing with biomass production and carbon sequestration by exotic and native species. This research presents information on biomass and carbon sequestration projections in reforested sites of northern Mexico. A total of 124 sampling plots were sampled for dasometric features and biomass components in the Mexican states of Durango, Coahuila, and Nuevo Leon of the Eastern and Western mountain ranges of northern Mexico. Results showed the potential carbon sequestration and biomass projections by component for each of three main regions separated by multivariate statistics and productivity curves. Mean annual carbon sequestration rates approach 3.90, 0.90, and 0.45 Mg ha^-1 y^-1 for reforested sites of the States of Durango, Nuevo Leon, and Coahuila, respectively. Native species of coniferous forests of Durango (P. durangensis, P. cooperii, and P. engelmannii) and Nuevo Leon (P. pseudostrobus) sequester carbon at higher rates than the introduced pine species of Durango (P. arizonica), Nuevo Leon (P. cembroides, P. pinceana, and P. nelsoni), and Coahuila (P. halepensis). Stands reforested are sequestered carbon at a higher rate than stands of native coniferous forests because of the largest plant density of the former sites, therefore they provide additional environmental benefits.

This report presents information on land use changes and carbon stocks and fluxes resulting from land use-change in the subtropical dry forest of the State of Morelos, Mexico. Biomass components of standing vegetation were estimated from 40 quadrats (400 m² each) distributed across this ecosystem. Regional land use changes using forest cover for two different periods (1976 and 1993) and present forest cover, as well as measurements of soil organic matter and soil organic carbon were used to predict carbon stocks and fluxes in this ecosystem. The results showed for the period of 1976-1993 that the annual deforestation rate is 0.87% indicating that approximately 20,000 ha of subtropical dry forest were lost during this period and that 57% of the original ecosystem has been lost since 1950. On the other side, intensive agriculture, including induced grasslands increased (22 000 ha) 15% of the total studied area largely at the expense of the tropical dry forest. Land use changes from the subtropical dry forest to agriculture contributed to carbon emissions of 6.49 Tg, of which standing biomass averaged 2.79 (± 0.28) Tg, root biomass averaged 1.75 (± 0.18) Tg, and soil organic carbon averaged 1.95 ( ± 0.2) Tg. Projected land-use changes will likely contribute to an additional carbon flux of 2.88 (± 0.14) Tg by the year 2050. Practices to conserve, sequester, and transfer carbon stocks in this ecosystem are discussed as a means to reduce carbon flux by deforestation practices.

Eddy covariance measurements of CO₂ were taken for five years above six forests distributed from the northern to southernmost main islands of Japan. These forests included cool- and warm-temperate deciduous and coniferous forests. The climate of Japan is characterized by apparent seasonal changes and adequate precipitation affected by the East Asian monsoon. In this report, we compared net ecosystem production (NEP) among forests using the eddy covariance method and analyzed the climatic factors that affect seasonal and inter-annual changes in NEP in relation to forest type. The observed annual NEP from 2000 to 2002 ranged from 286 to 566 gCm^-2yr^-1, and this basically increased with decreasing latitude. The observed maximum 10 days mean NEP was about 1.5 times larger in the deciduous sites, although the growing period was more than 2 times longer in the coniferous sites.

We report modeling experiments with a new global dynamic land model (LM3V), to reconstruct possible causes of the terrestrial carbon sources and sinks over the past century.  The model is unique, in that it is capable of representing the global history of land use, including the management of secondary forests (those forests that have re-grown at least once following harvest). Several published carbon inventories attribute the majority of the carbon sink caused by land use in the temperate zone to the management of secondary forests.

The present research is an attempt to examine and investigate the impact of land use land cover changes on the environmental sustainability and livelihood security of the local community in the Upper Kullu Valley of the Western Himalaya. Research is based on both the primary as well as secondary data sources. For the primary data were collected through Direct Field Investigation Technique (DFIT) based on Stratified Random Sampling (SRS) Technique. The secondary data were colleted from various Governmental as well nongovernmental offices working in the field of Himalayan environment and sustainability.

The objective of this study is to provide improved estimation of the area extent for major mire types within West Siberia (WS) and determine the spatial variability of NPP and biomass in relation to macro/micro landscape and site position within the bioclimatic division. Our approach relies upon scaling up available field survey and literature data to provide wetland net primary production (NPP) and biomass inventory maps for West Siberia. Both, satellite images and aerial photography classifications have been used to extrapolate site data into a regional inventory map (1:2.5M scale). Total NPP of wetlands is estimated as 530.5 TgDM (teragram/megaton dry matter)yr^-1, or 624.4 TgDM/yr when woody parts are included. Lowest NPP has been assigned to wetlands at the northern part of Taiga zone (4.5-6.2 tonDM)/ha/yr^-1). Wetlands in Tundra, Forested tundra and southern parts of Taiga zone show considerably higher NPP values. Minimum of living biomass storage was found in middle and southern taiga subzones. It is also increased to the north and south within West Siberian territory.

In this study, soil CO₂ effluxes determined from CO₂ concentration gradients were compared to effluxes obtained with automated chamber measurements. The CO₂ concentrations showed a diurnal pattern following the soil temperature the concentrations increasing with increasing soil depth. Both methods gave comparable CO₂ effluxes indicating that the gradient method provides an alternative method for monitoring soil CO₂ effluxes.

Based on satellite imagery for the 1988s and 2001s, land-use/cover change and associated carbon stock and flux as a result of changes were estimated in Mamlay watershed of Sikkim Himalaya, India. The total area of forest was decreased by 28%, whereas open cropped area increased by more than 100%. The conversion of forests into other land-uses resulted in a remarkable decline in the C densities. Across the land-use/cover, total mean C densities ranged from 46 t ha^-1 in open cropped area temperate to a high of 669 t ha^-1 in temperate natural dense forest. The heavily converted areas lost an estimated 55% of their total 1988 C pools, whereas the low impacted area lost only 0.12%. Changes in land-use released 7.78 tC ha^-1 yr^-1, demonstrating that land-use changes significantly affected C flux. Therefore, the conversion of forest to agriculture land should be reversed.

We report measurements of energy and carbon fluxes from a boreal forest fire chronosequence. Taking into account greenhouse gas emissions and post-fire changes in the surface radiation budget, a boreal forest fire in interior Alaska caused the climate to cool. This result suggests that management of forests in northern countries to preserve carbon sinks may have the opposite effect on climate as that intended.