Structure and Function of an Age Series of Eucalypt Plantations in Central Himalaya. I. Dry Matter Dynamics

The biomass and net primary productivity (NPP) of 2- to 8-year-oldplantations of Eucalyptus tereticornis Sm. (= E. hybrid) growingin the tarai (a level area of superabundant water) region ofCentral Himalaya were estimated. Allometric equations for allthe above-ground and below-ground components of trees and shrubswere developed for each stand. Understorey, forest floor biomassand litter fall were also estimated from stands. Shrubs appearedfirst at 5-year-old plantation. The biomass of vegetation, forestfloor littermass, tree litter fall and net primary productivity(NPP) of trees and shrubs increased with the increase in plantationage, whereas herb biomass and NPP significantly (P < 0·01)decreased with the increase in plantation age. The total plantationbiomass increased from 7·7 t ha^–1 in the 2-year-oldto 126·7 t ha^–1 in the 8-year-old plantation andNPP from 8·6 t ha^–1 year^–1 in the 2-year-oldto 23·4 t ha^–1 year^–1 in the 8-year-old plantation.The biomass accumulation ratio ranged from 0·81 to 5·93. Eucalyptus tereticornis Sm, plantation, biomass, forest floor, litter fall, net primary productivity, biomass accumulation ratio     

Structure and Function of an Age Series of Eucalypt Plantations in Central Himalaya, II. Nutrient Dynamics

This paper deals with nutrient dynamics in 2- to 8-year-oldplantations of Eucalyptus tereticornis Sm. previously investigatedfor dry matter dynamics. The nutrient concentrations changedin the order: herb > shrub > tree. The nutrient concentrationsin the different components of these vegetation types also decreasedwith plantation age. The nutrient content in trees and shrubsincreased and in herbs it decreased with increase in plantationage. The uptake of nutrients by vegetation and also by componentswith or without adjustment for retranslocation, has been calculatedseparately. Turnover time for different nutrients ranged between1.05 and 1.35 years. Compartmental models for nutrient dynamicshave been developed to represent the distribution of nutrientcontents and net annual fluxes within the system. Eucalyptus tereticornis plantation, nutrient concentration, standing state, uptake, turnover, nutrient cycling