Tree species

Pulp production and per capita consumption of paper and board for 1992 is shown in Table 8. The United States, Canada, Sweden, Finland, and Norway make up the North American and Scandinavian (NORSCAN) countries and produced about 63% (22.8 million tons) of the world output. Market share is growing for producers in Latin and South America, Western Europe, Asia, and Africa. These areas provide low cost pulp from state-of-the-art mills. Mills in the third world countries often enjoy the benefits of plentiful, fast-growing tree species, such as eucalyptus and tropical pines, and lower operating and labor costs (3). 

The Pedemontana Jungle sectors that have been left isolated are subject to edge effect, with changes clearly visible in microclimatic variables. The AGB in fragments is notably reduced for the main five tree species studied, but the species composition has also changed. 

The Ginkgo biloba tree is one of the oldest surviving tree species on earth (Major, 1967) and has probably existed in its current form for up to 200 million years, leading to its... 

Witherspoon, J.P. 1969. Radiosensitivity of forest tree species to acute fast neutron radiation. Pages 120-126 in D.J. Nelson and F.C. Evans (eds.). Symposium on Radioecology. Proceedings of the Second National Symposium. Available as CONF-370503 from The Clearinghouse for Federal Scientific and Technical Information, Natl. Bur. Standards, Springfield, VA 22151. 

Growing of different types of tree species (fruit, timber and fuel wood, medicinal, and aesthetic species) over time has been changing gradually. The fruit trees dominated much more over timber trees a few decades ago but the gap between them has diminished over time remarkably. A recent study conducted across the country showed that about 50 years ago, proportions of fruit and timber trees were 86% and 7%, respectively, which are now closer to 60% and 34%, respectively (Basak 2002). 

The receptors of interest are soils of agricultural (arable lands, grasslands) and non-agricultural (forests, steppes, heath lands, savanna, etc.) ecosystems. In non-agricultural ecosystems, the atmospheric deposition is the only input of heavy metals. Regarding the Forest ecosystems, a distinction should at least be made between Coniferous and Deciduous Forest ecosystems. When detailed information on the areal distribution of various tree species (e.g., pine, fir, spruce, oak, beech and birch) is available, this should be used since tree species influence the deposition and uptake of heavy metals and the precipitation excess. On a world scale, soil types can be best distinguished on the basis of the FAO-UNESCO Soil Map of the World, climate and ecosystem data from NASA database (1989). 

Within the defined areas, critical loads are calculated for all major combinations of tree species and soil types (receptors) in the case of terrestrial ecosystems, or water biota (including fish species) and water types in case of freshwater ecosystems. 

Table 9 compares the contents of heavy metals in the ash of various grass and tree species from the Savanna ecosystems of East Africa. We can see that nickel, barium, and strontium accumulate in the tree organs (twigs), whereas the accumulation of other metals is pronounced in grasses. 

The biogeochemical fluxes and exposure pathways of various macro- and microelements are different from those shown for Tropical Rain Forest ecosystems. The chemical composition of leaves of tree species in Mangrove Forest ecosystems is connected with higher content of Mg, Cl and S-SO4- and lesser content of K and Si as compared to the leaves of trees from Tropical Rain Forest ecosystems. The content of A1 is 3-4 times higher than that of Si and this can be related to the values of hydrogenic accumulation of these elements in soils (Figure 3). 

Kohno, Y., Matsumura, H., Kobayashi, T. (1998). Differential sensitivity of 16 tree species to simulated acid rain or sulfur dioxide in combination with ozone. In Bashkin, V. N., Park,... 

Pulping process Tree species Cellulose (%) Hemicellulose (%) Lignin (%) Extractives (%) ... 

Even so, most of the practical options available to individuals are low-cost, simple, and based on widely available information and resources. At the individual level, alternatives are most commonly implemented by growing ground covers other than turfgrass-either by simply aUovmig secondary succession to establish whatever diverse herbaceous, shmb, and tree species grow on a neglected plot, or instead by actively planting new communities, especially of native species. ... 

Jain, R.K. 1992. Fuelwood characteristics of certain hardwood and softwood tree species of India Biores Technol 41 129-133. 

Jain, R.K., Singh, B. 1999. Fuelwood characteristics of selected indigenous tree species from central India. Biores Technol 68 305-308. 

A weed can be an annual, a biennial, an herbaceous or shrubby perennial, or even a tree species. This chapter introduces you to the way weeds work—how and why they are so efficient—and the range of organic methods you can employ to clear weeds and keep them under control. It is useful to be able to identify common garden weeds, especially perennials (see pp.80-81). Knowing how they reproduce, spread, and survive adverse conditions can help you to develop an effective control strategy. 

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