The Structure and Function of Pine Forest in Central Himalaya. I. Dry Matter Dynamics

The present study deals with structure and function of fourareas of Himalayan chir pine forest. Tree layer was monospecificon all sites with varied density and basal cover in the rangeof 540–1630 individuals per ha and 25·0–47·2m²ha^–1, respectively. Shrubs having low density were sparselydistributed. All allometric equations relating to biomass ofdifferent components, to circumference at breast height (cbh)were significant, with the exception of that for cone biomass.Total vegetation biomass (115–236 t ha^–1) was distributedas 113–283 t ha^–1 in trees. 0·56–0·82t ha^–1 in shrubs and 1·63–2·57 t ha^–1in herbs. Total forest floor biomass including herbaceous litterranged between 9·6 and 13·6 t ha^–1. Of thetotal annual litter fall (4·26–7·38 t ha^–1),60·3–75·1 per cent was distributed in leaflitter and 24·9–39·7 per cent in wood litter.Turnover rate of tree litter varied from 0·45 to 0·53,whereas rates for shrubs and herbs were assumed to 1. Net primaryproduction of total vegetation ranged between 9·91 and21·2 t ha^–1 year^–1, of which the contributionof trees, shrubs and herbs was 76·5– 88·1per cent 0·6–1·8 per cent and 11·3–21·5per cent, respectively. A compartment model of dry matter onthe basis of mean data across sites was developed to show drymatter storage and flow of dry matter within the ecosystem. Pinus roxburghii forest, biomass, litter fall, net primary production, compartmental transfer     

Storage and Flux of Nutrients in a Dry Tropical Forest in India

Storage and flux of N, P, Ca, K and Na were studied in a drytropical forest The nutrient concentrations in different growthforms were in the order herb > shrub > tree, whereas thestanding state of nutrients followed the order tree > shrub> herb The total storage (kg ha^–1) in vegetation amountedto 567 N, 37 P, 278 Ca, 256 K and 46 Na The share of above-groundparts in vegetation storage was 82 % for N, 83 % for P, 76 %for Ca, 85 % for K and 79 % for Na From 56 to 71 % of foliarN, P and K was withdrawn during senescence Nutrient input (kgha^–1 year^–1) from the vegetation (above-ground +below-ground) to forest floor amounted to 115 N, 8 P, 62 Ca,38 K and 10 Na compared to total net annual uptake (kg ha^–1)of 143 N, 10 P, 78 Ca, 52 K and 12 Na, indicating marginal accumulationin the system Fine roots were as important a pathway of nutrientreturn as leaf litter Turnover rate and turnover time for differentnutrients on the forest floor ranged, respectively, between72 and 83 % and 12 and 1 39 years Dry tropical forest, nutnent concentration, standing state, uptake, internal cycling, turnover     

Structure and Function of High Altitude Forests of Central Himalaya II. Nutrient Dynamics

This paper deals with nutrient dynamics in horse chestnut, silverfir and kharsu oak forests in a high altitude region of CentralHimalaya. In general, the nutrient concentrations in differentlife forms were of the order: herb > seedling > shrub> sapling > tree, whereas the standing state of nutrientswere of the order: tree > herb > shrub > sapling >seedling. Of the total nutrients in the system, soil litterand vegetation, respectively accounted 66·5, 0·6and 32·9% in horse chestnut, 61·4, 0·8and 37·8% in silver fir, 58·1, 0·8 and41·1% in kharsu oak forests. Considerable reductionsin concentrations of nutrients in leaves occurred during senescence.Annual transfer of litter (above-ground+below-ground) to thesoil by vegetation of all forests ranged from 68-163 for N,4-7 for P, 26-48 for K, 62-150 for Ca and 2-4 kg ha^-1 year^-1for Na. Turnover time for different nutrients ranged between1·41 and 1·75 years for horse chestnut, 1·33and 2·13 years for silver fir, and 1·32 and 1·75years for kharsu oak forests. The distribution of nutrient contentsand net annual fluxes within the system have been developedto represent nutrient dynamics in compartment models.Copyright1995, 1999 Academic Press Standing state, turnover, retranslocation, nutrient concentration, internal cycling, uptake     

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 High Altitude Forests of Central Himalaya I. Dry Matter Dynamics

The present study deals with the structure and functioning ofthree different forest communities, viz., horse chestnut, silverfir and kharsu oak forests, in a high altitude region of CentralHimalaya. The tree density and total basal cover of horse chestnutforest was 280 and 76, silver fir forest 355 and 106, and kharsuoak forest 480 trees ha^-1 and 73 m² ha^-1, respectively. Allometricequations relating biomass of different tree components to cbh(circumference at breast height) were significant. Total vegetationbiomass was 505 t ha^-1 in horse chestnut, 566 t ha^-1 in silverfir and 593 t ha^-1 in kharsu oak forests, of which maximum contributionwas by tree layer followed by shrub, herb, sapling and seedlinglayers. The forest floor litter biomass was 2·1, 4·7and 4·2 t ha^-1 in horse chestnut, silver fir and kharsuoak forests, respectively. The total litter fall was 7·3,6·7 and 9·4 t ha^-1 year^-1, of which leaf littercontributed 48, 39 and 64% in horse chestnut, silver fir andkharsu oak forests, respectively. Turnover rate of tree litterwas 0·80 in horse chestnut, 0·61 in silver firand 0·71 in kharsu oak forests. Net primary productionof total vegetation was 19·6, 18·9 and 24·9t ha^-1 year-1, of which tree layer contributed maximum proportionfollowed by herb, shrub, sapling and seedling layers. To showdry matter storage and flow of dry matter within the system,compartment models were developed for all forests.Copyright1995, 1999 Academic Press Total basal cover, biomass, productivity, Quercus, Aesculus, Abies, high altitude, litter, compartmental transfer     

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

This paper elucidates nutrient dynamics in 5- to 8-year-oldpoplar (Populus deltoides) clone D₁₂₁ plantations previouslyinvestigated for dry matter dynamics. The nutrient concentrationin different layers of the vegetation were in the order: tree> shrub > herb, whereas the standing state of nutrientswere in the order: tree > herb > shrub. Soil, litter andvegetation, respectively, accounted for 80-89, 2-3 and 9-16%of the total nutrients in the system. Considerable reductions(trees 42-54, shrubs 31-37 and herbs 15-23%) in concentrationof nutrients in leaves occurred during senescence. The uptakeof nutrients by the vegetation and also by the different components,with and without adjustment for internal recycling, has beencalculated separately. Annual transfer of litter nutrient tothe soil by vegetation was 113·7-137·6 N, 11·6-14·6P and 80·1-83·2 K kg ha^-1 year^-1. Turnover rateand time for different nutrients ranged between 0·72-0·89year^-1 and 1·12-1·39 years, respectively. Thehigh turnover rate of litter on the forest floor indicates thegreater productivity of the stands, which was due to the higherdry matter dynamics and nutrient release for the growing vegetation.The nutrient use efficiency in poplar plantations ranged from159-175 for N, 1405-1569 for P and 295-332 for K. Compared withEucalyptus, there was a higher proportion of nutrient retranslocationin poplars largely because of higher tissue nutrient concentrations;this indicates lower nutrient use efficiency as compared tothe eucalypt plantation. Compartment models for nutrient dynamicshave been developed to represent the distribution of nutrientpools and net annual fluxes within the system.Copyright 1995,1999 Academic Press Populus deltoides plantations (Clone D₁₂₁), nutrient retranslocation, net nutrient uptake, nutrient use efficiency, nutrient cycling, nutrient pool, nutrient fluxes     

The Structure and Function of Pine Forest in Central Himalaya. II Nutrient Dynamics

This paper elucidates nutrient dynamics in a pine forest, previouslyinvestigated for dry matter dynamics. The nutrient concentrationsin different life forms were of the order: herb > shrub >tree whereas the standing state of nutrients were of the order:tree > shrub > herb. Soil, litter and vegetation respectivelyaccounted for 38·1–82·2, 2·4–3·7and 15·4–58·2 per cent of the total nutrientsin the system. Considerable reductions (52–69 per cent)in concentrations of nutrient in needles occurred during senescence.The uptake of nutrients by vegetation, and also by differentcomponents with and without adjustment for internal recycling,has been calculated separately. Annual transfer of litter tothe soil by vegetation was 76·21 N, 6·25 P, 57·24Ca, 14·22 Mg, 19·92 K and 1·92 kg ha^–1Na. Turnover rate and turnover time for different nutrientsranged between 0·40–0·64 and 1·56–2·50year, respectively. Compartment models for nutrient dynamicshave been developed to represent the distribution of nutrientcontents and net annual fluxes within the system. Nutrient concentration, standing state, uptake, internal recycling, nutrient return, turnover, nutrient cycling     

Nutrient Dynamics in Himalayan Alder Plantations

Dynamics of four macro-nutrients were studied in an age series(7, 17, 30, 46 and 56 years) of Himalayan alder (Alnus nepalensisD. Don) plantations in the Kalimpong forest division of theeastern Himalayas. Concentrations of nutrients were in the orderN > K > Ca > P in most of the tree components and inunderstorey vegetation. There was an inverse relationship betweennutrient concentrations of perennial parts and diameter at breastheight. The relative contributions of standing state of nutrientsin different tree components of mature plantations were in theorder; bole > branch > below-ground part > twig andleaf > catkin. Sequential arrangement of nutrient storagein tree components was: N > K > Ca > P. Soil totalN and available P increased with plantation age. Annual inputsof nutrients (kg ha^-1) to the forest-floor via litterfall were:183-235 N, 4·9-7·0 P, 33·5-39·5K, and 9·2-10·8 Ca. Total annual accretion ofN through biological fixation ranged from 29 to 117 kg ha^-1in different plantations. Turnover rate and turnover time fordifferent nutrients in the age series of plantations fluctuatedbetween 0·10-0·55 year^-1 and 1·8-9·3years, respectively. Nutrient use efficiencies decreased withplantation age for all nutrients except for calcium. Uptakeof nutrients is a more energy consuming process than release.Copyright1993, 1999 Academic Press Alnus nepalensis D. Don, plantation age, nitrogen accretion, nutrient concentration, standing state, uptake, turnover     

Structure and Function of Oak Forests in Central Himalaya. II. Nutrient Dynamics

This paper elucidates nutrient dynamics in oak forests previouslyinvestigated for dry matter dynamics. The nutrient concentrationsin different life forms were of the order: herb > shrub >tree, whereas the standing state of nutrients were of the order:tree > shrub > herb. Soil, litter and vegetation, respectively,accounted for 32·4–98·0 %; 0·3–3·5%, and 10·2–66·6 % of the total nutrientsin the system. Considerable reductions (8·5–41·7%)in concentrations of nutrients in leaves occurred during senescence.The uptake of nutrients by vegetation, and also by differentcomponents with and without adjustment for internal recycling,has been calculated separately. Annual transfer of litter (above+ below ground) to the soil by vegetation was 115·9–187N, 7·5–15·6 P, 122·7–195·1Ca, 36·1–48·8 K and 2·88–5·16Na kg ha^–1 yr^–1. Turnover rate and turnover timefor different nutrients ranged between 0·66–0·84yr^–1 and 1·19–1·56 yr^–1, respectively.Compartment models for nutrient dynamics have been developedto represent the distribution of nutrient contents and net annualfluxes within the system. Quercus leucotrichophora forest, Q.floribunda forest, Q. lanuginosa forest, Nutrient concentration, standing state, uptake, internal cycling, turnover     

Nutrient Cycling in an Age Sequence of Western Washington Douglas-fir Stands

The cycling of nitrogen, phosphorus, calcium, magnesium andpotassium in a series of western Washington Douglas-fir [Pseudotsugamenziesii (Mirb.) Franco] stands ranging in age from 9 to 95years has been described. The stands were of relatively lowproductivity being limited by low nitrogen. The content of nitrogen,phosphorus, magnesium and potassium in tree foliage all tendedto stabilize at about 40 years whereas calcium continued toincrease. The content of all nutrients in the wood continuedto increase with stand age. Nitrogen in the forest floor accumulatedconstantly at about 5.7 kg ha^–1 year^–1 and thistogether with the above-ground tree accumulation meant about10.5 kg ha^–1 year^–1 nitrogen was immobilized. Calciumalso increased with time in the forest floor with age whereasthe other nutrients were fairly constant after about 30 years.Understorey nutrient content reached a peak at about 20 years,while understorey litter-fall was significant throughout theage sequence. Internal redistribution, especially of nitrogen,represented an increasingly greater proportion of stand requirementwith increasing stand maturity. Pseudotsuga menziesti (Mirb.) Franco, Douglas-fir, biomass, litter-fall, nutrient content, nutrient cycling     

Structure and Function of Oak Forests in Central Himalaya. I. Dry Matter Dynamics

The present study deals with structure and functioning of threeareas of Himalayan oak forest. Low- and mid-altitude oaks, namelyQuercus leucotrichophora, and Quercus floribunda, form predominantevergreen forests in Central and Western Himalaya. The totaltree basal cover ranged between 33·89 m² ha^–1 (Q.floribunda site) to 36·83 m² ha^–1 (Q. leucotrichophorasite). The density ranged between 570 and 760 individuals ha^–1.Allometric equations relating biomass of different tree componentsto GBH (girth at breast height) were significant with the exceptionof leaf biomass in Q. leucotrichophora and Rhododendron arboreum.Total vegetation biomass (29·40–467·0 tha^–1) was distributed as 377·1 t ha^–1 intrees, 5·40 t ha^–1 in shrubs and 1·23 tha^–1 in herbs. Total forest floor biomass ranged between4·6 and 6·2 t ha^–1. Of the total annuallitter fall (4·7–4·8 t ha^–1), 77·5% was contributed by leaf litter, 17·8 % by wood litterand 4·7 % by miscellaneous litter. Turnover rate of treelitter varied from 0·66 to 0·70. Net primary productionof total vegetation ranged between 15·9 and 20·6t ha^–1 yr^–1, of which the contribution of trees,shrubs and herbs was 81·2 %, 8·6 % and 10·2%, respectively. A compartment model of dry matter on the basisof mean data across sites was developed to show dry matter storageand flow of dry matter within the system. Quercus leucotrichophora forest, Q. floribunda forest, Q. lanuginosa forest, biomass, litter fall, net primary production, compartmental transfer     

Species Structure, Dry Matter Dynamics and Carbon Flux of a Dry Tropical Forest in India

Species composition, plant biomass and net primary productivitywere studied on three sites of a dry tropical forest The forestwas characterized by small structure with 38–10.4 m2 ha^–1tree and 3 1–7 8 m² ha^–1 shrub basal cover Speciesdiversity was highest for the mid-slope site while the concentrationof dominance was greatest for the hill-top stand The beta diversitywas 3 1 Total standing crop of vegetation averaged 66 98 t ha^–1with 46 70 t ha^–1 in the tree layer, 13.97 t ha^–1in the shrub layer, 0.35 t ha^–1 in the herb layer, 2 83t ha^–1 in the litter layer and 3 13 t ha^–1 in fineroots Of the total annual litterfall (4 88–6.71 t ha^–1),69% was accounted for by leaves and 31% by non-leaf matter Netprimary production (NPP) ranged between 11 3 and 19 2 t ha^–1year^–1, to which the contributions of trees, shrubs andherbs averaged 72, 22 and 6%, respectively Contribution of rootsto NPP was substantial and ranged from 2 9 to 5 3 t ha^–1year^–1 A total of 83% of vegetation carbon was storedin the above-ground plant parts while the above-ground NPP wasresponsible for 72% of the total carbon input into the systemThe contribution of foliage, herbaceous vegetation and fineroots to carbon turnover was disproportionately larger comparedto their share in the total standing crop Carbon budgeting indicatedthat the forest was an accumulating system, over at least theshort term Dry tropical forest, biomass, litterfall, net primary production, carbon budget, carbon flux     

Structure and Function of an Age Series of Poplar Plantations in Central Himalaya: I Dry Matter Dynamics

The biomass and net primary productivity (NPP) of 5- to 8-year-oldpoplar (Populus deltoides Marsh, Clone D₁₂₁) plantations growingin the Tarai belt (low-lying plains with high water table adjacentto foothills of central Himalaya) were estimated. Allometricequations for all the above-ground and below-ground componentsof trees and shrubs were developed for each stand. Understorey,forest floor biomass, and litter fall were also estimated fromstands. The biomass of plantation, forest floor litter mass,tree litter fall and net primary productivity (NPP) of treesand shrubs increased with increase in plantation age, whereasherb biomass and NPP significantly (P < 0·01) decreasedwith increasing plantation age. The total plantation biomassincreased from 84·0 in the 5-year-old to 170·0t ha^-1 in the 8-year-old plantation and NPP from 16·8t ha^-1 year^-1 in the 5- and 6-year-old to 21·8 t ha^-1year^-1 in the 8-year-old plantation. The biomass accumulationratio (biomass: net production, BAR) for different tree componentsincreased with the age of plantation increase. The BAR ratioranged from 4·9 in the 5-year-old to 7·7 in the8-year-old plantation.Copyright 1995, 1999 Academic Press Populus deltoides plantations (Clone D₁₂₁), biomass, dry matter turnover, net primary productivity, Tarai belt of Central Himalaya     

Forest floor mass,litterfall and nutrient return in Central Himalayan high altitude forests

Dynamics of forest floor biomass, pattern of litter fall and nutrient return in three central Himalayan high elevation forests are described. Fresh and partially decomposed litter layer occur throughout the year. In maple and birch the highest leaf litter value was found in October and in low-rhododendron in August. The relative contribution of partially and more decomposed litter to the total forest floor remains greatest the year round. The total calculated input of litter was 627.7 g m^-2 yr^-1 for maple, 477.87 g m^-2 yr^-1 for birch and 345.9 g m^-2 yr^-1 for low-rhododendron forests. 49–61% of the forest floor was replaced per year with a subsequent turnover time of 1.6–2.0 yr. The annual nutrient return through litter fall amounted to (kg ha^-1 yr^-1) 25.5–56.1 N, 2.0–5.4 P and 9.9–23.3 K. The tree litter showed an annual replacement of 26–54% for different nutrients and it decreased towards higher elevation. The nutrient use efficiency in terms of litter produced per unit of nutrient was higher in present study compared to certain mid- and high-elevation forests of the central Himalaya.     

Biomass, Productivity and Energetics in Himalayan Alder Plantations

Biomass, net primary production and energy fixation in an agesequence of Himalayan alder (Alnus nepalensis D. Don) plantationswere estimated in the Kalimpong forest division of the easternHimalayas. Biomass in the plantations ranged from 106 t ha^–1(7-year stand) to 606 t ha^–1 (56-year stand) demonstratingthe potential of the alder for accumulating large biomass. Netprimary production and net energy fixation rates of the plantationswere reduced by nearly half in the 7-year stand (25 t ha^–1year^–1; 421 x 10⁶ kJ ha^–1 year^–1) comparedwith the 56-year stand (13 t ha^–1 year^–1; 215 x10⁶ kJ ha^–1 year^–1). Compartmental models of energystorage and flow rates were developed for the 7-year and 56-yearstands. The production efficiency, energy conversion efficiencyand energy efficiency in N₂ fixation have inverse relationshipswith plantation age. These efficiencies, when treated with eachother, showed significant exponential functions. Alnus nepalensis D. Don, Himalayan alder, plantation age, biomass, net primary production, energy flow, efficiencies     

Estimates of biomass and primary productivity in a high-altitude maple forest of the west central Himalayas

The paper describes the biomass and productivity of maple (Acer cappadocicum) forest occurring at an altitude of 2,750 m in the west central Himalayas. Total vegetation biomass was 308.3 t ha⁻¹, of which the tree layer contributed the most, followed by herbs and shrubs. The seasonal forest-floor litter mass varied between 5.4 t ha⁻¹ (in rainy season) and 6.6 t ha⁻¹ (in winter season). The annual litter fall was 6.2 t ha⁻¹, of which leaf litter contributed the largest part (59% of the total litter fall). Net primary productivity of total vegetation was 19.5 t ha⁻¹ year⁻¹. The production efficiency of leaves (net primary productivity/leaf mass) was markedly higher (2.9 g g⁻¹ foliage mass year⁻¹) than those of the low-altitude forests of the region.     

Microclimate, Photosynthesis and Growth of Lucerne (Medicago sativa L.). II. Canopy Structure and Growth

The growth of lucerne var. Europe was examined in the fieldduring 1976. The annual dry matter production of unirrigatedlucerne during 1976, with no nitrogen fertilizer application,was 82.5 per cent greater than unirrigated S.24 perennial ryegrass,with a nitrogen application of 384 kg ha^–1. The mean aboveground growth rate of lucerne was 7.3 g DM m^–2 day^–1between March and early June, of which stem material contributeda maximum of 76.5 per cent. Significant losses of leaves andstems occurred from the end of April, indicating a loss of potentialforage material. Nitrogen analyses of the above ground crop suggested that in56 days lucerne yielded 10.7 per cent more nitrogen than didS.24 annually with a nitrogen fertilizer addition of 280 kgha^–1. Between 13 and 57 per cent of the daily photosynthate is translocatedbelow ground. Medicago sativaL, lucerne, dry matter production, canopy structure, nitrogen analyses     

Decomposition and carbon cycling of dead trees in tropical forests of the central Amazon

Decomposition rate constants were measured for boles of 155 large dead trees (>10 cm diameter) in central Amazon forests. Mortality data from 21 ha of permanent inventory plots, monitored for 10–15 years, were used to select dead trees for sampling. Measured rate constants varied by over 1.5 orders of magnitude (0.015–0.67 year^–1), averaging 0.19 year^–1 with predicted error of 0.026 year. Wood density and bole diameter were significantly and inversely correlated with rate constants. A tree of average biomass was predicted to decompose at 0.17 year^–1. Based on mortality data, an average of 7.0 trees ha^–1 year^–1 died producing 3.6 Mg ha^–1 year^–1 of coarse litter (>10 cm diameter). Mean coarse litter standing-stocks were predicted to be 21 Mg ha^–1, with a mean residence time of 5.9 years, and a maximum mean carbon flux to the atmosphere of 1.8 Mg C ha^–1 year^–1. Total litter is estimated to be partitioned into 16% fine wood, 30% coarse wood, and 54% non-woody litter (e.g., leaves, fruits, flowers). Decomposition rate constants for coarse litter were compiled from 20 globally distributed studies. Rates were highly correlated with mean annual temperature, giving a respiration quotient (Q ₁₀) of 2.4 (10°C^–1). Received: 14 June 1999 / Accepted: 31 August 1999     

Dry matter and nutrient inputs through litter fall in a dry tropical forest of India

The present paper elucidates the pattern of leaf and non-leaf fall and quantifies of the total annual input of litter in a dry tropical forest of India. In addition, concentration of selected nutrients in various litter species and their annual return to the forest floor are examined. Total annual input of litter measured in litter traps ranged between 488.0–671.0 g m^-2 of which 65–72% was leaf litter fall and 28–35% wood litter fall. 73–81% leaves fall during the winter season. Herbaceous litter fall ranged between 80.0–110.0 g m^-2 yr^-1. The annual nutrient return through litter fall amounted (kg ha^-1): 51.6–69.6 N, 3.1–4.3 P, 31.0–40.0 Ca, 14.0–19.0 K and 3.7–5.0 Na, of which 71–77% and 23–29% were contributed by leaf and wood litter fall, respectively for different nutrients. Input of nutrients through herbaceous litter was: 13.0–16.6 for N, 1.0–1.4 for P, 4.0–5.0 for Ca, 7.9–10.5 for K and 0.8–1.0 kg ha^-1 yr^-1 for Na.     

Fine Root Productivity and Turnover in Two Evergreen Central Himalayan Forests

Fine root production and mortality in central Himalayan evergreenforests consisting of Quercus leucotrichophora (banj oak) andPinus roxburghii (chir pine) were measured. Fine root productionand mortality decreased with increasing soil depth. Annual fineroot production was higher in the broadleafed forest than inthe coniferous forest, across months and seasons (1.3 and 1.5-timesmore living and dead root biomass, respectively in banj oakthan in chir pine). Live fine root production was 2508 kg ha^-1year^-1inchir pine forest and 3631 kg ha^-1year^-1in banj oak forest. Deadfine roots accumulated at a rate of 1197 and 1525 kg ha^-1year^-1inchir pine and in banj oak forest, respectively. In both forests,the greatest fine root production was recorded in the rainyseason followed by summer and winter seasons. Both soil androot nitrogen concentration decreased with increasing soil depth.Nitrogen uptake was higher in banj oak forest (12.1 kg ha^-1year^-1)than chir pine forest (7.2 kg ha^-1year^-1).Copyright 1999 Annalsof Botany Company Fine root production, fine roots, necromass, banj oak, chir pine, Quercus leucotrichophora , Pinus roxburghii .