Forest Research Institute

About: Forest Research Institute is a facility organization based out in Dehra Dūn, India. It is known for research contribution in the topics: Population & Forest management. The organization has 5320 authors who have published 7625 publications receiving 185876 citations.

The role of mycorrhizas in the regeneration of some Malaysian forest trees

Abstract: An investigation was made into the availability of mycorrhizal inoculum and the response of tree seedlings to mycorrhizal infection in West Malaysian forests. Spores of vesicular arbuscular (VA) mycorrhizal fungi in the soil were reduced by 25% after selective logging and by 75% after heavy logging, VA infection in the roots of plants persisting on, or colonizing, a heavily logged site was reduced by up to 75% . The most probable number (MPN) of VA propagules in sieved soil was up to ten times greater than spore density, but was also greatly reduced by heavy logging. This resulted in reduced infectivity of soil from the heavily logged site, as demonstrated by reduced VA infection of bioassay plants. The infectivity of soil declined following sun drying, but sun-dried soil devoid of vegetation retained some infectivity even after 12 months storage. Overall the data suggest that root and hyphal fragments are more important than spores as inoculum in disturbed forest, and that in undisturbed forest living roots and hyphae are likely to be important sources of infection. In a pot experiment, shoot growth of two test species, Albizia falcataria (L.) Becker and Parkia speciosa Hassk. responded more to VA mycorrhizal infection than to P fertilization over the range 0-6 g triple superphosphate per 8 kg of soil. The response to inoculation with a cocktail of ‘introduced’ VA fungi propagated in pot cultures was greater than the response to inoculation with ‘indigenous’ fungi propagated in pot cultures from roots and soil collected in undisturbed forests. Another test species, Intsia palembanica Miq., also responded better to mycorrhizal infection than to P fertilization, and better to VA mycorrhizal infection than to ectomycorrhizal infection. Intsia palembanica seedlings growing around mature dipterocarps quickly became ectomycorrhizal, suggesting that at least some ectomycorrhizal fungi infect both dipterocarps and Intsia. Shorea leprosula Miq. seedlings growing naturally in the forest had ectomycorrhizas 20 days after germination, i.e. before they had true leaves, and within 7 months supported up to 11 different ectomycorrhizal fungi. However, seedlings isolated from contact with the roots of mature Shorea trees remained uninfected in the held for up to 6 months. This shows the importance of contact with living ectomycorrhizal roots for early infection of dipterocarp seedlings, a point which should be recognized in logging operations and forest regeneration programmes.

Climate and forest management influence nitrogen balance of European beech forests: microbial N transformations and inorganic N net uptake capacity of mycorrhizal roots

Abstract: The effects of local climate and silvicultural treatment on the inorganic N availability, net N uptake capacity of mycorrhizal beech roots and microbial N conversion were assessed in order to characterise changes in the partitioning of inorganic N between adult beech and soil microorganisms. Fine root dynamics, inorganic N in the soil solution and in soil extracts, nitrate and ammonium uptake kinetics of beech as well as gross ammonification, nitrification and denitrification rates were determined in a beech stand consisting of paired sites that mainly differed in aspect (SW vs. NE) and stand density (controls and thinning treatments). Nitrate was the only inorganic N form detectable in the soil water. Its concentration was high in control plots of the NE aspect, but only in canopy gaps and not influenced by thinning. Neither thinning nor aspect affected the abundance of root tips in the soil. Maximum nitrate net uptake by mycorrhizal fine roots of beech, however, differed with aspect, showing significantly lower values at the SW aspect with warm–dry local climate. There were no clear-cut significant effects of local climate or thinning on microbial N conversion, but a tendency towards higher ammonification and nitrification and lower denitrification rates on the untreated controls of the SW as compared to the NE aspect. Apparently, the observed sensitivity of beech towards reduced soil water availability is at least partially due to impaired N acquisition. This seems to be mainly a consequence of reduced N uptake capacity rather than of limited microbial re-supply of inorganic N or of changed patterns of inorganic N partitioning between soil bacteria and roots.

Influence of Chemical Modification and Filler Loading on Fundamental Properties of Bamboo Fibers Reinforced Polypropylene Composites

Abstract: The effects of chemical modification (silane coupling) and filler loading on the fundamental properties of the bamboo fiber (BF) filled polypropylene (PP) bio-composites were investigated in this study. Mechanical properties of the PP/ BF composites, such as the tensile strength, flexural strength, and impact strength decreased as BF loading increased. However, the tensile modulus, flexural modulus, and water absorption were increased by the increase of the BF loading. The addition of aminopropyltrimethoxysilane (AS) and tetramethoxy orthosilicate (TMOS) after the alkali pretreatment for the BF increased all the tensile, flexural, impact strength, and water desorption of the resultant composites, resulting from the improved adhesion between the BF and PP matrix. This tendency was more obvious with the increase of the BF loading. The melting temperature, melting enthalpy, crystallization enthalpy, and crystallinity were decreased by the increase of BF loading and the AS and TMOS treatments. One the other h...

On the delineation of tropical vegetation types with an emphasis on forest/savanna transitions

Abstract: Background: There is no generally agreed classification scheme for the many different vegetation formation types occurring in the tropics. This hinders cross-continental comparisons and causes confusion as words such as ‘forest’ and ‘savanna’ have different meanings to different people. Tropical vegetation formations are therefore usually imprecisely and/or ambiguously defined in modelling, remote sensing and ecological studies. Aims: To integrate observed variations in tropical vegetation structure and floristic composition into a single classification scheme. Methods: Using structural and floristic measurements made on three continents, discrete tropical vegetation groupings were defined on the basis of overstorey and understorey structure and species compositions by using clustering techniques. Results: Twelve structural groupings were identified based on height and canopy cover of the dominant upper stratum and the extent of lower-strata woody shrub cover and grass cover. Structural classifications di...