For. Stud. China, 2012, 14(4): 268-275 DOI 1O.1007/s11632-012-0409-6 I

Forest structure, diversity and regeneration in unburnt and burnt Anogeissus lat份， lia forests in Garhwal Himalayas

Munesh KUMARl*, Jahangeer A. BHATI, G. S. RAJWAR2

I Department ofForestry and Natura! Resources, HNB Garhwa! University, Srinagar Garhwa!, Uttarakhand 249161 , India 2 Department ofBotany, Govemment Post Graduate Col1ege, Rishikesh, Uttarakhand 249201 , India

。 Be司 ing Forestry University and Springer-Verlag Berlin Heide!berg 2012

Abstract The present study was carried out at two different gradients of unbumt and bumt Anogeissus latifolia forest sites in the Garhwal region, India. At each gradient, the unbumt and bumt forest sites were further categorized into three different e!evations, i.e. , !ower (700 m), midd!e (850 m) and upper (1 000 m). At each e!evation, the density oftrees, saplings and seedlings was higher at the unbumt sites except for 仕ees at the upper e!evation which was higher at the bumt sites. The tota! basa! area of each !ayer of for­ est was a!so higher at the unbumt sites. The study revea!ed that the !ower number of saplings and seed!ings at the bumt forest sites might be due to the effect of fire. Most trees in the !ower dbh classes were affected by forest fire at the bumt sites which reduced the tota! density and tota! basa! area of the trees comp缸'ed to the unbumt sites. The diversity oftrees increased with increasing e!evation. However, the diversity of sap!ings and seedlings reduced with increasing e!evation.

Key words Anogeissus latifolia, unbumt and bumt forest, e!evationa! gradient, diversi纱" regeneration

1 Introduction of plant succession. It is reported that 6 million km2 of forest have already been lost around the wor1d in less The vegetation of Himalayan forests ranges from than 200 years mainly due to forest fires (Dimopoulou tropical dry deciduous forests in the foothil1s to alpine and Giannikos, 2002). meadows above the timber1ine. Vegetation is the out­ Most forest fires are caused by human activities come of habitat, environmental conditions and exist­ and natural factors such as lightning sparks and fal1- ing biotic effects. In the Himalayan region, forest fires ing boulders. Most forest fires are set intentionally occur every year, affecting fiora, fauna, human liveli­ for land conversion and timber harvesting; socio-eco­ hoods and the local c1imate. Forest fires cause major nomic conf1icts over questions of property and land damage to the environment, health and property and use rights inc1ude deforestation (conversion of forest are increasingly receiving public attention global1y to other land uses, e.g. agricul阳re and pasture), use of during the last few years, due to their significant short­ non-wood forest products (using fire to facilitate har­ and long-term threats to forest ecosystems. The natu­ vest or improve yield of plants, fruits and other forest ral fire regimes in the dry deciduous forests of India products), management of grazing lands (自由 s set by are not wel1 known, but it is suggested that deciduous grazers), settlement fires (fires from settlements, e.g. forest communities do not evolve with fire as selec­ 企om cooking, torches and camp fires) and traditional tion pressure (Tumer et al., 1997; Menke and Muir, uses of fire (in the wake of religious and ethnic tradi­ 2004). However, anthropogenic fires cause forests to tions and tribal warfare). Large wildfires can eliminate tum into savannas, open their canopies and reduce for­ al1 the existing vegetation cover and may alter plant est stature (Vitousek et al., 1996; Keeley et al., 2003; community composition by providing ideal habitats Kuenzi et al., 2008). The ecological role of fire is to for non-native species (Keeley et 乱， 2003). Forest fire affect several aspects, suchas plant community de­ is a primary process affecting vegetation composition velopment, water conservation, soil nutrient recyc1ing and structure, which helps to shape the landscape mo­ and biological diversity. Forest fires are considered saic and affect biogeochemical cyc1es, i.e., the carbon vital natural processes that initiate the natural exercise cyc1e. Forest structure and composition, now and in .Author for correspondence. E-mail: [email protected] Munesh KUMAR et al.: Forest structure, diversity and regeneration in unbumt and bumt... 269

the past, are affected by fire regimes (Heinselman, unbumt and bumt A. latifolia forests. 1973; Wright and Bailey, 1982). Some parts of the Himalayan region are facing ma­ jor threats of forest fires annually. In the sub-tropical 2 Materials and methods parts of Garhwal Himalaya, Anogeissus latifolia for­ ests occasionally come under threat of forest fires, but 2.1 Studyarea wherever these forests grow close to Pinus roxburghii forests, they remain under threat of fire and sometimes The study was carried out in the Srinagar va11ey of the incur severe damage. As an agent of disturbance ，自由 Tehri Garhwal district, Uttarakhand. Geographi印ca剖11忖yf plays an important role in Pinus roxburghii, Picea the study area is situated between 30 。叮13'26 spinulosa and Pinus wallichiana forests (McKinnell, 78 0 48'10"咀E in the Gar由hwa剖1 Himalayan region, in the 2000), especially when these forests are located on dry northem part of Srinagar city, India (Fig. 1). The area sites. Pure stands of P wallichiana and P roxburghii is dominated by A. latifolia trees and the surrounding forests are destroyed by fire eve可 year. So far no 自由 peaks are covered by Pinus roxburghii forests, form­ studies have been carried out in A. latifolia forests in ing transitional boundaries where both forests are the Garhwal region. Therefore, we made an attempt mixed. A. latifolia is commonly found in dry as we11 to understand the effect of fire on A. latifolia forests as moist deciduous forests and grows on a variety of with the objectives: i) forest structure and diversity soils ranging from dry sandy loam, over1ying boul­ of unbumt and bumt A. lati声 lia forests at different ders and infertile kankar soils to deep moist loams elevations and ii) the regeneration of species in these (Luna, 2005). The soils of the area are we11 drained

78"O'O"E 79户。 '0'古巴 80.0 。吧 剧。0'0吧

U忧arakhand

780 0'0''E 78 0 20'0"E 78 0 40'0"E 790 0'0'军 A

30'50'0'1叶

300 40'0"N

300 30'0''N 广〉 Tehri Garhwal 30'20'0'1证

300 10'0'吁吁

30 0 0'0''N

10 20 40km

Fig. 1 Map of study area 270 Forestry Studies in China, Vo1.l 4, No.4, 2012

and acidic in nature. The study region has a monsoon (middle) and 1000 m (upper). In order to compare the type of climate with three differently marked seasons burnt forest sites with unburnt forest sites at the same (summer, rainy and winter) in a year. The mean an­ elevations (Figs. 2C & 2D), we selected unburnt sites nual temperature in this region varies between 10 0 C for vegetation analysis. and 23 0 C and the mean January temperature between 100 C and 15 0 巳 Total annual precipitation is 960 mm (Sheikh et al., 2011). The forest is under high levels of 2.2 Vegetation analysis anthropogenic pressure; if the rate of forest exploita­ tion remains constant the forest may be replaced by The vegetation analysis was carried out in a sub­ other species (Kumar et al., 2010). tropical forest of the Garhwal Himalayas, dominated To assess the effect of fire on vegetation, the total by A. latifolia and associated with Acacia catechu and burnt forest area (Figs. 2A & 2B) was categorized into Lannea coromandelica. A total of 10 quadrats (each of three different elevations, i.e. , 700 m (lower), 850 m 10m x 10m in size) were selected randomly at each

B

Fig. 2 Burnt forest sites (A, B) and unbumt forest sites (C , D) of study area Munesh KUMAR et al.: Forest structure, diversity and regeneration in unbumt and bumt... 271 elevation. The size and number of quadrats were de­ the unbumt site. The distribution pattem of A. latifolia termined by the species-area curve (Misra, 1968) and was contagious and Acacia catechu was distributed the running mean method (Kershaw, 1973). In each randomly at each elevation. Aegle marmelos was quadrat the trees were categorized as seedling (height distributed contagiously at the lower elevation, while < 20 cm), sapling (height 20-150 cm) and tree (dbh > Aegle marmelos and Lannea coromandelica were ran­ 10 cm at 1. 37 m from the ground). The vegetation data domly distributed at the upper elevation. were analyzed as described by Curtis and McIntosh In the bumt site, A. latifolia was the dominant tree (1 950) and the relative values ofthe importance value at all three elevations. The maximum density was index (IVI) by Curtis (1 959). The ratio of abundance 1110, 870 and 980 plants'ha-' for A. lat伪 lia at the to frequency (A/F ratio) was used to represent the dis­ lower, middle and upper elevations, respectively. The tribution pa忧em (Whitfo时， 1949). This ratio indicates total basal area was also higher for A. latifolia at lower 2 I 2 l regular distribution if it is < 0.025, random if between (6.780 m 'ha- ) , upper (8.900 m 'ha- ) and middle 2 l 0.025-0.050 and contagious if> 0.050. The diversity (2 .490 m 'ha- ) elevations. The distribution pattem of (H) was ca1culated for each stratum (tree, sapling and all species at the lower elevation was contagious. At seedling), using density data as per Shannon and Wie­ the middle elevation, A. latifolia and Lannea coro­ ner (1 963): mandelica were distributed contagiously and Acacia S 艾1η i. ni catechu was regular in its distribution. At the upper =一〉 γlogz -=- elevation A. lati庐 lia and Emblica officinalis were both 古î ,. ,. 1) distributed contagiously and other species were regu­ where n; is the importance value of each species, n the lar in distribution (Table 1). total importance value of all the species in a stand and S the number of species in the stand. Concentration of dominance (CD) was determined as described by 3.2 Sapling layer Simpson's index (Simpson, 1949): S At the unbumt site, A. latifolia was the common spe­ CD= 三(号 )2 cies in the sapling layer, with density values of 260, 2) i=l 20 and 240 plants'ha-' at the lower, middle and upper Equitability (EC) was calculated following Whit­ elevations. The highest total basal area of A. latifolia taker (1 975) using density values as follows: was 0.059 m2'ha-1 at the lower elevation, which re­ EC = S/(log N; 一 logN) duced at the middle and upper elevations. A. latifolia was found randomly distributed at upper and lower el­ where N; and Ns are the density values of the most and least important species, respectively. evations and contagiously distributed at the middle el­ evation (Table 1). Lannea coromandelica and Acacia catechu were also distributed contagiously at middle 3 Results and discussion and upper elevations (Table 1). At the bumt site, A. latifolia was the only single 3.1 Tree layer species present at the lower elevation, with a density 2 l of 80 plants'ha-' and total basal area of 0.016 m 'ha- . In the unbumt site at the lower elevation, the maxi­ At the middle elevation, A. latifolia was present with mum density was 1690 plants'ha-1 in the tree layer and Acacia catechu with a density of 60 plants'ha-' and the total basal area 15.970 m2'ha-1 for A. latifolia, with total basal area ofO.012 m2'ha-l , while at the upper el­ 1 a minimum density (1 0 plants'ha- ) and total basal evation its density was 50 plants'ha-' with a total basal 2 1 2 area (0.100 m 'ha- ) for Aegle marmelos (Table 1). At area of 0.001 m 'ha-1, with its co-dominant species the middle elevation only two tree species, A. latifolia Lannea coromandelica. A. latifolia and Lannea coro­ and Acacia catechu, were recorded with density value mandelica were distributed contagiously at the upper of 1660 plants.ha-1 and 200 plants'ha-1 and total basal elevation. However, A. lat价 lia was found regularly at area of 5.720 m2 'ha一 1 and 2.940 m2'ha-1, respectively. lower and middle el 巳vations and Acacia catechu con­ At the upper elevation, the maximum density was tagiously at the middle elevation (Table 1). 1 again recorded for A. latifolia (620 plants'ha- ) fol­ 1 lowed by Lannea coromandelica (240 plants'ha- ) , 1 Aegle marmelos (1 40 plants'ha- ) and Acacia catechu 3.3 Seedling layer 1 (40 plants'ha- ) , with maximum and minimum total 2 1 basal area for A. latifolia (6.960 m 'ha- ) and Aegle At the unbumt site, the density of A. latifolia seedlings 2 1 1 marmelos (0.770 m 'ha- ). A. latifolia was found as was 580, 230 and 740 plants'ha- at lower, middle the dominant species among the three elevations at and upper elevations, respectively. The density of NJ 可M

Iàble 1 Frequency, densi纱， total basal area, importance value index and A/F ratio oftrees, saplings and seedlings in unbumt and bumt forest sites at different elevations Layer Species Lower (700 m) Middle (850 m) Upper (1 000 m) F D (plants. TBA IVI A/F F D (plants. TBA IVI A/F F D (plants. TBA IVI A/F (%) ha- ) (m2.ha- l) (%) ha- ) (m2.ha-l) (%) ha- ) (m2.ha- l) ，， ' ' ' dAAAobc ωωmuα lc afu旷3 a ncoa ω ι Tree Unbumt d 100 1690 15.970 260.92 0.169 100 1660 5.720 210.84 0.166 100 620 6.960 149.03 0.062 川 ，巾 M H 30 40 1.220 30.81 0.044 80 200 2.940 89.16 0.031 40 40 0.800 24.27 0.026 Aegle marmelos 10 10 0.100 8.27 0.100 60 140 0.770 40.83 0.039 Lannea coromandelica 80 240 4.430 85.86 0.038 1740 17.290 1860 8.660 1040 12.960 Bumt Anogeissus latifolia 100 1110 6.780 217.56 0.111 100 870 2.490 205.59 0.087 100 980 8.900 216.06 0.098 Acacia catechu 60 210 1.650 68.22 0.058 80 90 1.070 77.98 0.014 40 40 0.900 29.00 0.025 h μnMEI 队 山 m m.m 2ll c 。 mω vad 巾 20 20 0.140 14.22 0.051 20 20 0.160 16.43 0.051 80 80 0.380 44.20 0.012 庐 叫 m 汕 S 20 20 0.060 10.73 0.051 1340 8.570 980 3.720 1120 10.240

Sapling Unbumt Anogeissus lat协 lia 90 260 0.059 300.00 0.032 20 20 0.006 75 .47 0.051 60 240 0.010 252.24 0.031 Lannea coromandelica 40 80 0.020 224.53 0.052 Acacia catechu 10 10 0.002 47.75 0.100

260 0.059 100 0.026 250 。 .012

Bumt Anogeissus lat功 lia 80 80 0.016 300.00 0.012 50 60 0.012 233.24 0.024 40 50 0.001 87.58 0.100 Acacia catechu 10 20 0.004 66.76 0.200 l nu Lannea coromandelica 10 0.052 212.42 0.074 吧。 80 0.016 80 0.016 60 0.053 gmHq Seedling Unbumt Anogeissus latifolia 100 580 0.037 300.00 0.058 100 230 0.021 18 1.99 0.023 100 740 0.052 275.75 0.074 ∞ Lannea coromandelica 40 200 0.016 118.01 0.125 ε 坠 Aegle marmelos 20 40 0.001 24.25 0.100 gsnFEP 580 0.037 430 0.037 780 0.053 Bumt Anogeissus latifolia 100 260 0.019 280.47 0.026 70 170 0.013 271.06 0.027 100 390 0.020 286.89 0.039 Lannea coromandelica 10 20 0.001 19.53 0.200 20 20 0.001 28.94 0.200 10 10 0.0003 13.11 0 .1 00 〈。 ---Afz 280 0.020 190 0.014 400 0.020

= = = 2 I) = Note: F frequency (%), D density (plants.ha-'), TBA total basal area (m .ha- , IVI importance value index. 。 -AFMO

巳 Munesh KUMAR et al.: Forest structure, diversity and regeneration in unburnt and burnt... 273

seedlings of Lannea coromande/ica at the middle el­ also revealed in their study that young plants became evation was 200 plants'ha-1 and for Aegle marmelos more affected by fires than mature ones. 40 plants'ha-I at the upper elevation. A. latifolia was In the sapling stage the total density and total basal found contagiously distributed at both lower and up­ area of the present study decreased again at the bumt per elevations whereas at the middle elevation it was forest sites compared to unbumt forest sites at each regular in distribution. However, Lannea coromandel­ elevation. Similarly in the seedling layer, total density icαand Aegle marmelos were distributed contagiously and total basal area also reduced compared to unbumt at middle and upper elevations (Table 1). forest sites. It was observed that the reduction in total At the bumt site, A. latifolia and Lannea coroman­ density and total basal area at bumt forest sites could delica seedlings were recorded at all three elevations be due to the devastating effect of fire at bumt forest but the density of A. latifolia was maximum at all sites which damages large numbers of saplings and three elevations compared to Lannea coromandelica seedlings. Levin (1 976) also suggested that severe dis­ (Table 1). The distribution pa仕em of A. latifolia was turbance has a very harmful effect on regeneration. random at all three elevations, while Lannea coroman­ Among the species, distribution pa忧ems were gen­ delica was found contagiously distributed at all three erally reported in all categories. Odum (1 971) reported elevations (Table 1). that a contagious distribution pa忧em of species is the The total tree density at unbumt sites was 1740, most common pa忧em in nature. Random distribution 1860 and 1040 plants'ha-1 at lower, middle and up­ pattems are reported in very uniform environments; per elevations, respectively, which was comparatively however, a regular distribution pattem suggests that severe competition exists between species (Panchal higher than those at the bumt sites at the same eleva­ and Pandey, 2004; Kumar et al., 2010). tions. The total basal area was also lower at the bumt sites compared to the unbumt sites (Table 1). The lower values of total density and total basal area of 3.4 Diversity, concentration of dominance trees at the bumt sites might be due to the damages and equitability of trees caused by fire, especially in the lower dbh classes. Kumar et al. (2004) also carried out a study At the unbumt forest sites, tree diversity (H) was in a similar forest where total density ranged from maximum (H = 1.50) at the upper elevation and mini­ 832 to 884 trees'ha一 I and total basal area of 14.30 to (H = , 2 l mum 0.21) at lower elevation while concentra­ 24.83 m 'ha- • In another study ofKumar et al. (2008) tion of dominance (CD) was maximum (CD = 0.94) in an A. latifolia forest of this region, they reported at the lower elevation and minimum (CD = 0.43) at I total density ranging from 990 to 1150 trees'ha- and upper elevation (Table 2). The maximum diversity of 2 l total basal area from 8.753 to 10.448 m 'ha- • Kafle trees at the upper elevation might be caused by mild (2006) carried out a study in a deciduous dipterocarp­ anthropogenic pressure. However, minimum diversity oak forest in Doi Suthep-Pui National Park in northem at the lower elevation might be due to the fact that the Thailand, by taking a protected area and a bumt site area, near human habitation, has high levels of an­ for study. The results of the study revealed that the thropogenic pressure. But at the bumt sites the highest protected area contained 25% more individual trees diversity (H = 0.73) was found at the lower elevation and higher number of young growth than the bumt (Table 2), which decreased at the middle elevation (H site. This suggests that fire protection in protected ar­ = 0.58) and again increased at the upper elevation (H eas decreases the level of damage to trees and in tum, = 0.72). The high anthropogenic pressure on the forest increases the productivity and organic matter content close to human habitation is due to the fact that vil­ in the soil and creates favorable conditions for the lagers usually use various resources, i.e., fodder, fuel, growth offurther species. Naidu and Srivasuki (1 994) timber, gum, agricultural implements and medicines

Table 2 Diversity, concentration of dominance and equitability of trees, saplings and seedlings in unbumt and burnt forest sites at different elevations Layer Lower (700 m) Middle (850 m) Upper (1 000 m) Unburnt Burnt Unburnt Burnt Unburnt Burnt H CD EC H CD EC H CD EC H CD EC H CD EC H CD EC Tree 0.21 0.94 1.34 0.73 0.71 1.7 1 0.49 0.81 2.17 0.58 0.80 1.83 1.50 0.43 3.36 0.72 0.77 2.36 Sapling 0.72 0.68 3.32 0.81 0.63 4.19 0.24 0.92 0.65 0.72 Seedling 0.37 0.87 1.79 1.00 0.50 32.95 0.49 0.81 2.15 0.29 0.90 0.17 0.95 1.25

Note: Diversity (的， concentration of dominance (CD) and equitability (EC). 274 Fores町 Studies in China, Vo1.l4, No.4, 2012

from the forest (Kumar et al., 2010). from 4 .46 to 9.09 for saplings and from 3.99 to 9.69 The diversity of saplings at the unbumt forest sites for seedlings. was higher (H = 0.72) at the middle elevation and lower (H = 0.24) at the upper elevation. The sapling diversity at the bumt forest sites was again higher (H References = 0.81) at the middle elevation and lower (H = 0.65) at the upper elevation. The concentration of dominance Curtis J T. 1959. The Vegetation ofWisconsin: An Ordination (CD) at both unbumt and bumt forest sites presented of Plant Communities. Madison: University of Wisconsin a reverse trend compared to diversity, i.e., higher at Press, 657 Curtis J T, Mclntosh R P. 1950. The interrelations of certain the upper elevation and lower at the middle elevation analytic and synthetic phytosociological characters. Ecology, (Table 2). In the seedling layer of the unbumt forest 31:434-455 sites, the higher diversity (H = 1.00) was found at the Dimopoulou M, Giannikos 1. 2002. Towards an integrated middle elevation and lower (H = 0.29) at the upper 企amework for forest fìre control. Eur J Oper Res, 152: 476- elevation, whereas at the bumt forest sites, the higher 486 diversity (H = 0.49) was found at the middle elevation Heinselman M L. 1973. Fire in the virgin forests ofthe Bound­ 缸y Waters Canoe Area, Minnesota. Quat Res, 3: 329-382 and lower diversity (H = 0.17) at the upper elevation. Kafle S K. 2006. Effect of forest fire protection on plant diver­ The concentration of dominance also presented a re­ sity in a tropical deciduous Dipterocarp-Oak forest, Thailand. verse trend with diversity (Table 2). Int Forest Fire News, 34: 64-71 The diversity of trees at unbumt sites increased Keeley J E, Lubin D, Fotheringham C J. 2003. Fire and grazing with increasing elevation whereas concentration of impacts on plant diversity and alien plant invasions in the dominance showed a reverse trend with elevation. In southern Sierra Nevada. EcolAppl, 13: 1355-1374 Kershaw K A. 1973. Quantitative and Dynamic Plant Ecology. the sapling and seedling layers the diversity decreased 2nd edn. London: Edward Arnold Ltd., 308 with increasing elevation. In this study the values Kue皿 i A M, Fulé P Z, Sieg C H. 2008. Effects of fire severity of diversity ranged between 0.21-1. 50 for trees, and pre-fire stand treatment on plant community recovery 0.24-0.81 for saplings and 0.17-1.00 for seedlings. In after a large wildfire. Forest Ecol Manage, 255: 855-865 a similar forest of this region, Kumar et al. (2006) re­ Kumar M, Bhatt V P, Rajwa:τG S. 2006. Plant and soil diversi­ ported that diversity ranged between 0.846-1.710 for ties in a sub 位opical forest of the Garhwal Himalaya. Ghana J Forest, 19&20: 1-19 trees, 1.1 00-1.520 for saplings and 0 .496-1.435 for Kumar M, Joshi M, Todaria N P. 2010. Regeneration status of a seedlings. sub-tropical Anogeissus lat价 lia forest in Garhwal Himalaya, Fire may potentially reduce the biodiversity of the India. J Forest Res, 21(4): 439-444 area. Gaps created by high-intensity fires are particu­ Kumar M, Sharma C M, Rajwar G S, Mishra A. 200 1. Com­ lar1y susceptible to invasion of exotic species which munity structure and plant biodiversity in relation to distur­ may deplete the biodiversity of an area through alle­ bance gradient in temperate forest of Garhwal Hiamalya. Van Vigyan, 39(1-4): 1-9 lopathic pathways.τhe findings of our study conclude Kumar M, Sharma C M, Rajwar G S. 2004. A study on the that saplings and seedlings are severely affected by community structure and diversity of a sub-tropical forest of fire, although trees were affected only in lower dbh Garhwal Himalayas. Indian Forest, 130(2): 207-214 classes because of their susceptibility to damage by Kumar M, Singh B, Joshi M. 2008. Effect of aspect on distribu­ forest fires. tion pa忧ern of Anogeissus latifolia (Wall Ex Bedd) in sub­ At unbumt sites, the equitability of trees was high­ tropical belt of Garhwal Himalaya, India. Tanzania J Forest NatConserv, 78: 21-27 est (EC = 3.36) at the upper elevation, followed by Levin S A. 1976. Population dynamics models in heteroge­ middle (EC = 2.17) and lower (EC = 1.34) elevations. neous environments. Ann Rev Ecol Syst, 7: 287-310 At bumt forest sites the equitability followed a similar Luna R K. 2005. Plantation Trees. Dehradun: International trend as at unbumt forest sites, which increased with Book Distributors increasing elevation (Table 2). Kumar et al. (2008) Mckinnell F. 2000. Forest fìre management in Bhutan. Consul­ reported that equitability ranged 企om 2.880 to 3.582, tancy Report, TFDP, PFO, Khangma, Trashigang, eastern Bhutan, 26 similar to A. latifolia forests in Garhwal Himalaya. Menke C A, Muir P S. 2004. Short-term influence of wildfire on In the sapling layer the equitability was 3.32 at un­ canyon grassland plant communities and Spalding's catchfly, bumt forest sites and 4.19 at bumt forest sites. In the a threatened plant. Northwest Sci, 78: 192-203 seedling layer the 10 Misra R. 1968. Ecolog Munesh KUMAR et al.: Forest structure, diversity and regeneration in unburnt and burnt... 275

Rampara forest in Saurashtra region of Gujarat state of India. Yel1owstone National Park. Ecol Monogr, 67: 411 -433 Trop Ecol, 45(2): 223-231 Vitousek P M, D' Antonio C M, Loope L L, Westbrooks R. Shannon C E, Wiener W E. 1963. A Mathematical Theory of 1996. Biological invasions as global environmental change. Communication. Urbana, USA: University of Illinois Press, Am Sci, 84: 468-478 117 Whitford P B. 1949. Distribution ofwoodland plants in relation Sheikh M A, Kumar M, Bhat J A. 201 1. Wood specific gravity to succession and clonal growth. Ecology, 30: 199-208 Whittaker R H. 1975. Communities and Ecosystems. 2nd edn. of some tree specie咀 in the Garhwal Himalayas, India. Forest Stud China, 13(3): 225-230 New York: Macmil1an Publishing Co Wright H A, Bailey A W. 1982. Fire Ecology: United States and Simpson E H. 1949. Measurement of diversity. Nature, 163: Southem Canada. New York: John Wiley and Sons, 501 188 Turner M G, Romme W H, Gardener R H, Hargrove W W. (Received December 3, 2011 Accepted February 13, 2012) 1 997. Effects of fire size and pa仕em on early succession in