The Impact of Recycling on the Long-Run Stock of Trees

Interest in recycling of forest products has grown in recent years, one of the goals being to conserve the stock of trees or possibly increase it to compensate for positive externalities generated by the forest and neglected by the market. This paper explores the issue as to whether recycling is an appropriate measure to attain such a goal. We do this by considering the problem of the private owner of an area of land, who, acting as a price taker, decides how to allocate his land over time between forestry and some other use, and at what age to harvest the forest area chosen. Once the forest is cut, he makes a new land allocation decision and replants. He does so indefinitely, in a Faustmann-like framework. The wood from the harvest is transformed into a final product which is partly recycled into a substitute for the virgin wood, so that past output affects the current price. We show that in such a context, increasing the rate of recycling will result in less area being devoted to forestry. It will also have the effect of increasing the harvest age of the forest, as long as the planting cost is positive. The net effect on the flow of virgin wood being harvested to supply the market will as a result be ambiguous. The main point however is that recycling will result in a smaller, not a larger, stock of trees in the long run. It would therefore be best to resort to other means if the goal is to increase the stock of trees.

A characterization of fuzzy trees

In this paper some properties of fuzzy bridges are studied.A characterization of fuzzy trees is obtained using these concepts.

Convex extendable trees

The concept of convex extendability is introduced to answer the problem of finding the smallest distance convex simple graph containing a given tree. A problem of similar type with respect to minimal path convexity is also discussed.

Wild food trees in Eastern Nuba Mountains, Sudan: Use diversity and threatening factors

This study was conducted in 2010 in Eastern Nuba Mountains, Sudan to investigate ethnobotanical food and non-food uses of 16 wild edible fruit producing trees. Quantitative and qualitative information was collected from 105 individuals distributed in 7 villages using a semi-structured questionnaire. Also gathering of data was done using a number of rapid rural appraisal techniques, including key informant interviews, group discussion, secondary data sources and direct observations. Data was analysed using fidelity level and informant consensus factor methods to reveal the cultural importance of species and use category. Utilizations for timber products were found of most community importance than food usages, especially during cultivated food abundance. Balanites aegyptiaca, Ziziphus spina-christi and Tamarindus indica fruits were asserted as most preferable over the others and of high marketability in most of the study sites. Harvesting for timber-based utilizations in addition to agricultural expansion and overgrazing were the principal threats to wild edible food producing trees in the area. The on and off prevailing armed conflict in the area make it crucial to conserve wild food trees which usually play a more significant role in securing food supply during emergency times, especially in times of famine and wars. Increasing the awareness of population on importance of wild food trees and securing alternative income sources, other than wood products, is necessary in any rural development programme aiming at securing food and sustaining its resources in the area.

Use of decision trees in colour feature selection: application to object recognition in outdoor scenes

A new method for the automated selection of colour features is described. The algorithm consists of two stages of processing. In the first, a complete set of colour features is calculated for every object of interest in an image. In the second stage, each object is mapped into several n-dimensional feature spaces in order to select the feature set with the smallest variables able to discriminate the remaining objects. The evaluation of the discrimination power for each concrete subset of features is performed by means of decision trees composed of linear discrimination functions. This method can provide valuable help in outdoor scene analysis where no colour space has been demonstrated as being the most suitable. Experiment results recognizing objects in outdoor scenes are reported

Trees

Trees innit

Moonligth, seas, and chocolate trees.

Esta antología ofrece una extensa selección de obras de muy diferentes géneros, que abarcan la ficción,la poesía, y no ficción. La selección de autores es igualmente amplia, de los poetas clásicos y autores modernos a los favorito de los niños, y de Shakespeare a los periodistas de hoy. Cada volumen de la antología corresponde a un solo año del ciclo superior de la escuela primaria. Para niños entre siete y once años.

Learn about trees.

Proporciona una visión general de los árboles, sus componentes, la forma en que crecen, cómo se calcula su edad,las variedades de árboles, y cómo usamos los árboles y sus productos. Cómo se produce la fotosíntesis y la razón por la que es importante para cada uno de nosotros. Se incluye una serie de experimentos diseñados para ampliar los conocimientos, desarrollar la comprensión de la experiencia práctica y la investigación.

Geological and fossil evidence.

La historia de la Tierra y de las diferentes formas de vida sobre ella se pueden conocer mediante el estudio de las rocas, los estratos, los fósiles y los restos animales y humanos conservados. Al final del libro hay una pequeña bibliografía y direcciones de páginas web.

Rock and fossil hunter.

Para saber qué buscar, dónde ir, y consejos de expertos sobre las rocas y la búsqueda de fósiles es lo que se ofrece en esta publicación con más de treinta actividades que ayudan a los niños a explorar, observar, y entender el mundo natural que les rodea, de forma educativa y divertida. Incluye una lista del equipo necesario y consejos útiles sobre cómo sacar el máximo provecho del estudio de las rocas y los fósiles. Algunas actividades tiene que realizarse en compañía de adultos y están identificadas con un símbolo. También incluye dos desplegables, que muestran la forma de identificar los principales tipos de rocas, minerales y fósiles que los niños pueden encontrar en los sitios más accesibles.

Trees.

Esta guía explica qué es un árbol, cómo se clasifican los árboles y la forma de llevar un registro de los árboles que han visto. Para ayudar en las etapas iniciales de identificación, el libro proporciona una clave visual que muestra las diferencias entre coníferas y palmeras, identifica a cada género y tipo de hoja, con un código de colores para un rápido reconocimiento de las especies. Con más de 500 especies de árboles, tiene 1.500 fotografías y un glosario que define los términos técnicos y científicos.

Developing Purposeful Mathematical Thinking : a Curious Tale of Apple Trees. 'Desarrollo de un pensamiento matemático intencionado : un relato curioso de manzanos'.

Resumen basado en el de la publicación