ORIGINAL ARTICLE

Cindy Q. Tang

Forest vegetation as related to climate and soil conditions at varyingaltitudes on a humid subtropical mountain, Mount Emei, Sichuan, China

Received: 26 July 2004 / Accepted: 12 July 2005 / Published online: 3 September 2005� The Ecological Society of Japan 2005

Abstract Altitudinal variations in temperature and soilswere analysed on a humid subtropical mountain, MtEmei (3,099 m a.s.l., 29�34.5¢N, 103�21.5¢E), in Sichuan,China, to see how the vegetation varies with the envi-ronmental factors. As a principal finding, the coldestmean monthly temperature �1�C, rather than thewarmth index of 85�CÆmonths, emerged as the primaryfactor that delimited the evergreen broadleaved forest.With regard to soils, properties such as organic C, totalN, available P, exchangeable K tended to increase withaltitude. The highest values in organic C (26.6%), totalN (1.34%) and available P (45.39 ppm) were recorded insurface soils of the mixed forest (2,210 m a.s.l.) includingall three tree life forms, i.e. evergreen/deciduous broad-leaved and coniferous trees. The high pH and contentsof exchangeable Ca and Mg in the surface soils derivedfrom the parent material, limestone and dolomite, be-tween 900 and 1,200 m, where several Tertiary treespecies existed. The C/N ratios of surface soils in theconiferous forests (2,500–3,099 m) were higher thanthose of the evergreen broadleaved forests (600–1,500 m) and the mixed forests (1,500–2,500 m).

Keywords Altitudinal forest zones Æ Coldest meanmonthly temperature Æ Soil properties Æ Tertiary treespecies Æ Warmth index

Introduction

The altitudinal zonation of forest formation on eastAsian mountains on a latitudinal gradient from 20� to30�N shows a transition between tropical and temperatezonation types (Ohsawa 1993). Mt Emei (3,099 m a.s.l.,

29�34.5¢N, 103�21.5¢E) reflects the transitional pattern.The natural range of subtropical Chinese forests is fromlatitude 22� to 35�N. However, the majority of China’sforests have been cleared for agricultural purposes orreplaced with tree plantations (Wang 1961; Dickermanet al. 1981; Wu 1983; Wang 1987; Winkler 1997). Thenatural forests that remain are only found in some iso-lated stands and in preserved areas or steeply slopingsites. They harbour a high diversity of species and sup-port the coexistence of three tree life forms, evergreenbroadleaved, deciduous broadleaved and coniferoustrees. The eastern slope of Mt Emei, Sichuan, China,contains a remnant of the native primary forests thatrepresents most of the natural vegetation patterns of thesubtropical forests of China.

Variation in the plant distribution, floristic compo-sition and structure of montane forests is often inter-preted in the context of gradients of elevation andtopography (Whittaker 1978; Peet 1981; Ohsawa 1985;Gagnon and Bradfield 1987; Cogbill and White 1991;Ware et al. 1992; Ohsawa 1995; Fang et al. 1996; Takyuet al. 2002). Kira (1977, 1991) and Ohsawa (1990) re-ported that the warmth index (WI) and the coldestmonthly temperature (CMT) can explain these vegeta-tion changes in humid monsoon Asia. Soil propertiesvary with altitude and topographic position (Whittakeret al. 1968; Grieve et al. 1990; Chen et al. 1997). Webb(1969), Grubb (1977), Johnston (1992) and Oliveira-Filho et al. (1997) demonstrated how soils limit thedistribution of tree species and forest types.

Tang and Ohsawa (1997, 1999, 2002a, b) conducteddetailed studies on the forest vegetation of Mt Emei. Li(1990) briefly described the altitudinal soil zones of theeastern slope, but did not present quantitative soilcharacteristics. Information on altitudinal variationaccording to thermal conditions and soils has remainedseverely limited. The significant variations are com-pressed into short distances on Mt Emei, and give us agood opportunity for the study of the relationships ofvegetation and environmental factors (climate and soils).Study of the relationships among vegetation, climate

C. Q. TangInstitute of Ecology and Geobotany, Yunnan University,650091 Kunming, Yunnan, ChinaE-mail: cindytang@ynu.edu.cnTel.: +86-871-2263598Fax: +86-871-5032753

Ecol Res (2006) 21:174–180DOI 10.1007/s11284-005-0106-1

and soils on Mt Emei can contribute to a better under-standing of altitudinal zonation in east Asia. Theobjective of this paper is to show how these environ-mental variables affect the forests.

Materials and methods

Study area

The study area, Mt Emei (3,099 m a.s.l., 29�34.5¢N,103�21.5¢E), is made up of deep canyons and steepslopes leading into very narrow gorges. The landformand geology of this mountain were described by Liu(1996). Mt Emei has a long history compared to theHimalayas, which were formed on the southwestern sideof the Tibetan plateau approximately 40 million yearsago (Guan 1982). It dates from the late CretaceousPeriod, around 70 million years ago (Zhao and Chen1980). From its base at about 551 m, the mountain risesto an altitude of 3,099 m.

The rainfall is abundant, without a dry season. Thegeneral climate of the study area is represented by thetwo climatic stations in the mountain area: at 3,047 ma.s.l. (Jinding on one peak of this mountain) and at447 m a.s.l. (Emeishan City). The mean annual rainfallis 1,786 mm at Jinding and 1,528 mm at Emeishan City.The peak rainfall, in August or July, coincides with themaximum mean temperature, about 11�C at 3,047 ma.s.l., 26�C at 447 m a.s.l. The study area is stronglyinfluenced by southeasterly monsoon winds duringsummer. According to Li (1990), the rate of precipita-tion increases by 49.6 mm for every 100 m altitude up to1,200 m a.s.l., then by 36.5 mm/100 m between 1,200and 2,300 m a.s.l. However, it decreases progressively by58.7 mm/100 m above 2,300 m a.s.l., so that the highestaverage annual precipitation is approximately 2,300 mmat around 2,300 m a.s.l. On average, the peak has 322foggy days per year, with 85% relative humidity. ForEmeishan City, the numbers are 95 (foggy days) and81% (humidity). Since the humidity is always high withlittle variation, and the mountainous area is overcast foralmost the entire year, here we only consider air tem-perature as the climatic factor related to forest zones.

The zonal soils on Mt Emei comprise yellow soils(500–1,800 m a.s.l.), yellow brown soils (1,800–2,200 ma.s.l.), dark brown soils (2,200–2,600 m a.s.l.) andpodzols (2,600–3,099 m a.s.l.) (Li 1990).

Measurements

We adopted the vegetation data of Tang and Ohsawa(1997).

The air temperature was measured using OpticStowAway Temp equipment equipped with radiationand rain shield, from May 1999 to April 2001 at 660,1,660, 1,960, 2,210, 2,425 m, and from May 2000 toApril 2001 at 780, 1,160, 2,825, 3,095 a.s.l., ranging from

low-altitude evergreen broadleaved forest to mid-altitude mixed forest and high-altitude coniferous forestenvironments. Thermal conditions at additional alti-tudes were estimated from observation data at thenearest measured altitudes using altitudinal differencesand lapse rates. Since the lapse rates vary daily andmonthly within different altitudinal segments, they wereextrapolated for every month and every altitudinal seg-ment, using thermal data from nearby measured alti-tudes.

A representative soil profile was investigated in eachplot at the following altitudes along the eastern slope.The pit numbers (P) are the same as those of the plots:660 m (P1), 780 m (P2), 965 m (P3), 1,160 m (P4),1,620 m (P5), 1,660 m (P6), 2,210 m (P7), 2,425 m (P8),2,825 m (P9) and 2,945 m (P10). The plots correspondedto those we had previously selected for study (Tang andOhsawa 1997). To characterize the physical structure ofthe soils, their solid, liquid, and gaseous volume wasmeasured using a three-phase meter (DIK-1121; Daiki),and five soil core samples were collected in each plot forthe analysis. Surface soils in each plot were sampled onsunny days, 10–15 May 1999, for measurements of pH,nutrients (total N, organic C, available P, K,exchangeable Ca, and Mg). Soil acidity (pH) was mea-sured in water with a soil/solution ratio of 1/2.5 using apH meter (EC-10; Hack.). Organic C content wasdetermined by the Tyurin method. Total N was ascer-tained by the micro Kjeldahl procedure after digestionwith concentrated H2SO4 and measurement of NH3 bythe indophenol blue method on an autoanalyser.Available P was extracted with 0.03 N NH4F/0.025 NHCI and analysed by the molybdenum–tellurium com-parative colour method. Available K was extracted with1 N NH4OAc. Exchangeable Na was exchanged andextracted with 1 N NH4OAc, and was analysed by flamespectroscopy. Exchangeable Ca and Mg were extractedwith EDTA–ammonium chloride and analysed byatomic absorption spectroscopy. The chemical analysiswas performed by the Soil Fertilizer Institute, SichuanAcademy of Agriculture Science, Chengdu, China.

Results

Vegetation and thermal conditions along altitudes

The forest vegetation is intact on the eastern slopeexcept for a secondary forest at 660 m (plot 1) due tohuman activities. Table 1 gives a general description ofthe plots along the altitudinal gradient. The three forestzones, as identified and detailed by Tang and Ohsawa(1997) were: (1) evergreen broadleaved forest zone at600–1,500 m a.s.l. (plots 2–4); (2) mixed forest zone at1,500–2,500 m a.s.l., comprising evergreen/deciduousbroadleaved mixed forest at 1,500–2,000 m a.s.l. (plot 6)and broadleaved and coniferous forests at 2,000–2,500 m a.s.l. (plots 7 and 8); and (3) coniferous forestzone at 2,500–3,099 m a.s.l. (plots 9 and 10). As the

175

altitude increased, the dominant species gradually shif-ted from the evergreen broadleaved trees such asMachilus pingii, Phoebe zhennan, Michelia martini, Illi-cium henryi, Actinodaphne omeiensis, Lindera pulcherr-ima, Lindera megaphylla and Lithocarpus cleistocarpusto deciduous broadleaved Tapiscia sinensis, Pterostyraxpsilophylla, Prunus grayana, Acer sinense and Acer fla-bellatum, then to coniferous Tsuga chinensis, Taxuschinensis and Abies fabri. Notably, fagaceous trees wereabsent at 900–1,200 m. In addition, a patch of Tertiaryrelic deciduous forest was found on a scree slope at ca.1,620 m a.s.l. (plot 5) where it was dominated by Davidiainvolucrata and Cercidiphyllum japonicum var. sinense.

Figure 1 shows the altitudinal changes in tempera-tures. At increasing altitudes, the temperature de-creases, at varying lapse rates (Fig. 1a). According tothe observed data at nine altitudes (see Materials andmethods section), the mean annual lapse rate was0.46�C/100 m at 660–780 m, 0.54�C/100 m at 780–1,660 m, 0.47�C/100 m at 1,660–2,210 m, 0.55�C/100 mat 2,210–2,425 m and 0.30�C/100 m at 2,425–3,095 m.The annual temperature range was slightly higher inthe middle altitudes (e.g. 18.7�C at 2,210 m) than in thelow and high altitudes (e.g. 18�C at 660 m and 17�C at3,095 m) (Fig. 1b). The coldest mean monthly temper-atures occurred in January or February, from �5.3�C(3,095 m) to 4.5�C (660 m), while the warmest meanmonthly temperatures occurred in July, from 11.5�C(3,095 m) to 22.5�C (660 m). Over the course of a year,the variations in temperature were marked by thestrong seasonality that characterizes the temperatezone, in contrast with the small diurnal changes(Fig. 1c). The isotherms in winter (December–Febru-ary), steeply curving toward high altitudes, show theeffect of the outflow of the Siberian cold air mass. Thewinter cold limited the distribution of tropical ever-green broadleaved plants toward the upper-middlealtitude on Mt Emei.

Figure 2 presents the forest zones with the climaticparameters WI and CMT on Mt Emei. A CMT of �1�Coccurs at 1,600 m while the WI of 85�CÆmonths corre-sponds to 1,160 m. It shows that the CMT of �1�C ismore effective as an upper limit of evergreen broad-

Table 1 General description of plots

Plot no. Altitude(m)

Plot size(m2)

Basal area of plot(cm2/100 m2)

Dominantspecies

No. ofspecies

Maximumheight (m)

MaximumDBH (cm)

P1 660 400 2,415 Ch, Pm, Cl 9 27 52P2 780 400 2,845 Mp, Pz 18 22 44P3 965 300 7,297 Mm, Ih 20 33 135P4 1,160 200 3,065 Ao, Lp, Lm, Ep 13 20 38P5 1,620 400 4,791 Di, Cj 18 23 63P6 1,660 600 5,103 Mp, Lc, Sc, Ts, Pp, As, Pg 22 27 104P7 2,210 1,600 2,909 Lc, Af, Abf, Tsc, Tac 31 26 93P8 2,425 400 1,829 Af, Pp, Am, Ve, Abf, Tsc 25 18 42P9 2,825 600 4,798 Abf 9 18 44P10 2,945 200 3,810 Abf 11 13 34

Ch: Castanopsis hystrix, Pm: Pinus massoniana, Cl: Cunninghamia lanceolata, Mp: Machilus pingii, Pz: Phoebe zhennan, Mm: Micheliamartinii, Ih: Illicium henryi, Ao: Actinodaphne omeiensis, Lp: Lindera pulcherrima, Lm: Lindera megaphylla, Ep: Euptelea pleiospermum, Di:Davidia involucrata, Cj: Cercidiphyllum japonicum var. sinense, Lc: Lithocarpus cleistocarpus, Sc: Symplocos caudata, Ts: Tapiscia sinensis(correcting the erroneous name Choerospondias axillaris given in Tang and Ohsawa 1997), Pp: Pterostyrax psilophylla, As: Acer sinense,Pg: Prunus grayana, Af: Acer flabellatum, Abf: Abies fabri, Tsc: Tsuga chinensis, Tac: Taxus chinensis, Am: Acer maximowiczii, Ve:Viburnum erubescens, DBH: diameter at breast height

Temperature (oC)

3000

500

1000

1500

2000

2500

-10 -5 0 5 10 15 20 25

Warmest mean monthly temperature (July)

Annual temperature range

Coldest mean monthly temperature (Feb.)Coldest mean monthly temperature (Jan.)

10-5

0055

15

20

J F M A M J J A S O N D J

Month

22 446

810

12 1416

03000

500

1000

1500

2000

2500

Time of day

Month

-10

-5

0

5

10

Mea

n an

nual

tem

pera

ture

(o C

)A

ltitu

de (

m)

Alti

tude

(m

)

15

20

25

J F MA M J J A S O N D

660 m1160 m

2210 m2425 m3095 m

1660 m

Altitude

a

b

c

0 2 4 6 8 10 12 14 16 18 20 22 24

Fig. 1 Temperature regimes for different altitudes (a), annualtemperature ranges (b) and isotherms (c)

176

leaved forests than the WI of 85�CÆmonths on thissubtropical mountain, as the minimum temperature inwinter limits the distribution of most evergreen broad-leaved trees toward higher altitudes. These results are arevision of data presented by Tang and Ohsawa (1997),who using the temperature data of two stations at 447 m(Emeishan City) and at 3,047 m (Jinding at one peak ofEmei mountain), and additional temperature data takenat different altitudes in the Sichuan basin area (inWenchuan, Boaxing and Yaan), found that the CMT of�1�C occurred at ca. 2,200 m, and the WI of 85�CÆ-months at ca. 1,600 m. The inaccurate figures from theother sites are replaced here by readings taken on MtEmei itself.

In general, deciduous forest can occur where themean annual temperature range exceeds 20�C (Wolfe1979). Mt Emei is near the southern boundary of thedistribution of deciduous forests. Its annual range oftemperature <20�C (Fig. 1b) may explain why it lacksan apparent altitudinal deciduous forest zone. The truemixed forest zone is formed at WI ca. 68–36�CÆmonthsat around 1,500–2,500 m a.s.l.

The upper limit of mountain forests generally corre-sponds to a temperature-sum WI of ca. 15�CÆmonths(Kira 1948). On Mt Emei, the coniferous forest grows atWI 36–18.5�CÆmonths between 2,500 and 3,099 m a.s.l.,and almost reaches the summit at 3,099 m a.s.l.

Altitudinal changes in soils

Physical properties of soils

The physical characteristics of soils varied along thealtitudes (Fig. 3). Plots 2, 7–9 and 10 lay over the samegeological substrate, basalt, and the total depth of soilstended to decrease with increasing altitude (Fig. 3a). Theyellow soils under a Machilus–Phoebe forest at 780 m(plot 2) had well-developed A and B horizons. The yellowbrown soils under the Lithocarpus–Acer–Tsuga–Abiesforest at 2,210 m (plot 7) were well structured, with veryclear boundaries among the A, B and C horizons. Thedark brown soils under the Acer–Tsuga–Abies forest at2,425 m (plot 8) had a greater total depth of A and ABhorizons. The soils under the Abies forest at 2,825 m(plot 9) were weakly podzolic with a thicker Ao horizonand a shallow A horizon. This probably resulted from thelow decomposition rate of coniferous litters. A well-developed podzol under the Abies forest at 2,945 m (plot10), remarkably, showed thick layers of both litter (Aohorizon) and humus (A horizon), as well as an excep-tional combined depth of A, AB, B and BC. In the yellowsoil zone, plots 3, 4 and 6 overlay limestone, dolomite

Climatic zonal forest

Eastern slope

Con

ifer

ous

fore

st

Mix

ed f

ores

t

Ev.

&D

ec.

Ev.

,Dec

.&

Con

if.

Dec

.&C

onif

.

Eve

rgre

enbr

oad-

leav

ed f

ores

t

Abies

AbiesTsugaAcerAbiesTsuga

LithocarpusAcer

LinderaActinodaphne

MicheliaIlliciumPhoebeMachilus

Euptelea

Machilus

LithocarpusTapiscia

PrunusAcer

Pterostyrax

Castanopsis

Castanopsis

500

1000

1500

2000

2500

3000

0 40 80 120

W I = 85

W I ( οC months)

Alti

tude

(m

)

C MT (οC )

C MT = -1

-6 -4 -2 0 2 4 6

Fig. 2 The climatic forest zones along the eastern slope on MtEmei with two temperature parameters: the coldest mean monthlytemperature (CMT) and warmth index (WI). Closed circles indicateobserved data. Open circles indicate estimated data. Ev Evergreenbroadleaved, Dec deciduous broadleaved, conif coniferous

0

10

20

30

40

50

60

70

80

90

100

A oA

A B

B

C

110

A o

A

B

B C

C

A oA

B

B C

C

A oA

A B

B

C

A oA

B

C

A oA

A B

B

C

A oAB

B C

C

A o

A B

A

B

B C

C

A oA

A B

B

C

A oA

A B

B

CSoild

epth

(cm

)

Mud

ston

e

Bas

alt

Lim

esto

ne

Dol

omite M

udst

one

& S

ands

tone

Sand

ston

e

Bas

alt

Bas

alt

Bas

alt

Bas

alt &

Mud

ston

e

Altitude (m) 660 780 965 1160 1620 1660 2210 2425 2825 2945

P1 P2 P3 P4 P5 P6 P7 P8 P9 P10Plot

Zonal soi ls Y S Y BS D BS Pod

102030405060708090100

0

Perc

enta

ge (

%)

P1P2 P3 P4 P5P6 P7 P8 P9P10Plot

Solid phase

Liquid phase

Gaseous phase

a

b

Fig. 3 Ten soil profiles (a), and three phases of the surface soils (b)in plots 1–10 (P1–P10). YS Yellow soils, YBS Yellow brown soils,DBS dark brown soils, Pod podzols [the colours of zonal soilsaccording to Li (1990)]

177

and sandstone, respectively. Plots 1 and 5 did not showvery clear horizons. The soils’ unclear horizons indicatetheir instability. The instability of soils at 660 m (plot 1)was mainly due to human disturbances, while at 1,620 m(plot 5) it was the result of the steep gradient.

In surface soils (A horizon), the liquid phase formed alarger proportion (>42%) at 1,660–3,099 m (plots 6–10)than at 600–1,620 m (<29%, plots 1–5) (Fig. 3b). Thescree slope at 1,620 m (plot 5) had a relatively largeproportion (29.2%) in the solid phase, with only 25.39%in the liquid phase.

For all the plots, soil moisture was so high that thepF value (water-holding capacity) could not be mea-sured using a porous ceramic-capped tensiometer (DIK-3130 HM type; Daiki).

Chemical properties of soils

The levels of organic C, total N and available P pre-sented almost similar patterns, peaking in the mixedforest of three tree life forms at 2,210 m (plot 7) andtending to increase with altitude (Fig. 4). Plot 7 hadthe highest values of organic C (26.6%), total N(1.34%) and available P (45.39 ppm). The soils athigher altitudes (plots 8–10) had a higher C/N ratiothan those of the other forests. Exchangeable K fluc-tuated from 0.4 to 0.83 me/100 g and tended to in-crease with altitude. The exchangeable Ca and Mgshowed a pattern similar to that of the pH. Plot 6 at1,660 m had the highest ratio of exchangeable Ca toMg. The pH value in plots 2, 6–8 and 10 slightlyfluctuated from 3.8 to 4.35. Plots 3–5 had the high pHvalues (>6) while they had low ratios of exchangeableCa to Mg. The high pH value in plots 3 and 4 derivedfrom the bedrock of limestone and dolomite, respec-tively (Fig. 3). Plot 1 showed the lowest value of each,which may result largely from human disturbance inthis secondary forest.

Discussion

Temperature influence on forest zones

The evergreen broadleaved forests are distributed at600–1,500 m a.s.l. on Mt Emei. A CMT of �1�C occursat 1,600 m while the WI of 85�CÆmonths corresponds to1,160 m. The CMT of �1�C is more effective as an up-per limit of evergreen broadleaved forests than the WI of85�CÆmonths on Mt Emei (Fig. 2). This conclusionagrees with Ohsawa’s (1990) results: the �1�C isotherm(range �2 to 1�C) coincides closely with the northern/upper limit of evergreen broadleaved forests. However,neither temperature condition WI nor CMT can accountfor the upper limit of some individual evergreenbroadleaved canopy trees, such asMachilus sichuanensis,Castanopsis platyacantha. They exceed the upper limit of

the evergreen broadleaved forest, 1,500 m, and mix withdeciduous trees to form a distinctive evergreen/decidu-ous broadleaved forest at 1,600–1,700 m. Some otherevergreen broadleaved canopy trees Schima sinensis(Theaceae), Quercus (Cyclobalanopsis) oxydon, Castan-opsis platyacantha and Lithocarpus cleistocarpus, reachup to 1,820, 1,880, 2,150 and 2,250 m, respectively (Tangand Ohsawa 1999). This phenomenon is also reminiscentof another grouping as represented by the sclerophyllousevergreen fagaceous trees in the Himalayas (26.20–30.10� N) of Nepal, Quercus semecarpifolia, which reachan altitudinal limit of 3,800 m (Hara et al. 1982),whereas 3,500 m is the upper limit for the warm-temperate evergreen broadleaved forest (Ohsawa 1985).Q. semecarpifolia is distributed at 2,000–3,700 m from

0

10

20

30

C(%

)

0

10

20

C/N

0

20

40

P(p

pm

)

0

0.4

0.8

K(m

e/1

00g)

0.4

0.8

1.2

N(%

)

0

Mg

(me/

100g

)0

10

20

500

1000

1500

2000

2500

3000

Ca(

me/

100

g)

0

20

40

60

Altitude (m)

Altitude (m)50

0

1000

1500

2000

2500

3000

0

4

8

12

Ca

/Mg

P1

P2

P3P4 P5

P6 P7

P8 P9

P10

0

2

4

6

8

pH(H

2O)

Fig. 4 The chemical properties for surface soils at differentaltitudes. Soil acidity (pH), organic C (C), total N (N), availableP (P), the ratio of organic C to total N (C/N), available K (K), Ca(Ca) and Mg (Mg), the ratio of exchangeable Ca to Mg (Ca/Mg)

178

Afghanistan to Southwest China (Negi and Naithani1995).

Soil influence on forest zones

Variation in soil properties results from the heteroge-neity of parent materials, topography and vegetationwithin a defined climatic region (Jenny 1941; Huddle-ston and Riechen 1973; Feldman et al. 1991). Thesechanges indicate that forest types with different domi-nant species are strongly associated with soil character-istics, bringing out the importance of abiotic factors tothese ecosystems.

The mixed forest, including three tree life forms at2,210 m, has the most fertile soils. The Tertiary treessuch as evergreen Michelia martinii, Illicium henryi andthe Tertiary relic deciduous species Euptelea pleiosper-mum on this mountain seem to favour soils with a highconcentration of exchangeable Ca and Mg, andrelatively low ratio of Ca/Mg. On the other hand, thesharply delineated absence of fagaceous trees at 900–1,200 m suggests that the high pH may limit their dis-tribution. An experimental approach is needed to ex-plain the phenomenon of the absence of fagaceousspecies.

In the Costa Rica transect study (Marrs et al. 1988)and Kinabalu transect study (Kitayama 1992) the au-thors reported an increased C/N ratio, perhaps indicat-ing a lower degree of N mineralization. C/N ratios >20are found in the forests at 2,425, 2,825 and 2,945 m a.s.l.on Mt Emei. The N availabilities for plants may belimited on these soils. At the higher altitudes on MtEmei, cold temperatures may reduce nutrient inputsfrom N fixation and slow the rate of decomposition. Thehigher C/N ratios on Mt Emei are attributable to thelower decomposition rate characteristic of coniferouslitters as well as to the lower temperature.

Acknowledgements I thank Professor Masahiko Ohsawa for givingvaluable advice on this study and offering the Optic StowAwayTemp equipment. Thanks also to the Ecological Laboratory ofChiba University, which gave financial support for the chemicalanalysis of soils. Finally, I am grateful to Professor Ming-Hua Luoof the Sichuan School of Chinese Materia Medica for his assistancein the fieldwork. Preparation of this paper was supported by ChinaNational Key Basic Research Program grants 2003CB145103 and2000–026.

References

Chen ZS, Hsieh CF, Jiang FY, Hsieh TH, Sun IF (1997) Rela-tionships of soil properties to topography and vegetation in asubtropical rain forest in southern Taiwan. Plant Ecol 132:229–241

Cogbill CV, White PS (1991) The latitude–elevation relationshipfor spruce-fir forests and treeline along the Appalachianmountain chain. Vegetatio 94:153–175

Dickerman MB, Duncan DP, Gallegos CM, Clark FB (1981)Forestry today in China. J Forestry 79:71–75

Fang JY, Ohsawa M, Kira T (1996) Vertical vegetation zones along30�N latitude in humid East Asia. Vegetatio 126:135–149

Feldman SB., Zelazny LW, Baker JC (1991) High-elevation forestsoils of the southern Appalachians. I. Distribution of parentmaterials and soil–landscape relationships. Soil Sci Soc Am J55:1629–1637

Gagnon D, Bradfield GE (1987) Gradients analysis of west centralVancouver Island forests. Can J Bot 65:822–833

Grieve IC, Proctor J., Cousins SA (1990) Soil variation with alti-tude on Volcan Barva, Costa Rica. Catena 17:525–534

Grubb PJ (1977) Control of forest growth and distribution on wettropical mountains: with special reference to mineral nutrition.Annu Rev Ecol Syst 8:83–107

Guan ZT (1982) The geography of conifers in Sichuan (in Chinese).Sichuan People’s Press, Chengdu

Hara H, Chater AQ, Williams LH (1982) An enumeration of theflowering plants of Nepal, vol 3. Trustees of the British Mu-seum (Natural History), London

Huddleston JH, Riecken FF (1973) Local soil–landscape relation-ships in western Iowa. I. Distribution of selected chemical andphysical properties. Soil Sci Soc Am Proc 37:264–270

Jenny H (1941) Factors of soil formation. A system of quantitativepedology. McGraw-Hill, New York

Johnston MH (1992) Soil–vegetation relationships in a tabonucoforest community in the Luquillo Mountains of Puerto Rico.J Trop Ecol 8:253–263

Kitayama K (1992) An altitudinal transect study of the vegetationon Mount Kinabalu, Borneo. Vegetatio 102:149–171

Kira T (1948) On the altitudinal arrangement of climatic zones inJapan (in Japanese). Kanti-Nougaku (Tokyo) 2:143–173

Kira T (1977) A climatological interpretation of Japanese vegeta-tion zones (in Japanese). In: Miyawahi A, Tuxen E (eds) Veg-etation science and environmental protection. Maruzen, Tokyo,pp 21–30

Kira T (1991) Forest ecosystems of East and Southeast Asia in aglobal perspective. Ecol Res 6:185–200

Li CG (1990) The natural vertical zones on the east slope of Mt.Emei in Sichuan province (in Chinese). Mount Res (China)8:39–44

Liu HR (1996) Visitor’s guidebook to the geology and landscape ofMount Emei (in Chinese). Chengdu University of Science andTechnology, Chengdu, China

Marrs RH, Proctor J, Heaney A, Mountford MD (1988) Changesin soil nitrogen-mineralization and nitrification along an alti-tudinal transect in tropical rain forest in Costa Rica. J Ecol76:466–482

Negi SS, Naithani HB (1995) Oaks of India, Nepal and Bhutan.International Book Distributors, Dehra Dun, India

Ohsawa M (1985) Altitudinal zonation of forest vegetation onMount Kerinci, Sumatra: with comparisons to zonation in thetemperate region of east Asia. J Trop Ecol 1:193–216

Ohsawa M (1990) An interpretation of latitudinal patterns of forestlimits in South and East Asian mountains. J Ecol 78:326–339

Ohsawa M (1993) Latitudinal pattern of mountain vegetationzonation in southern and eastern Asia. J Vegetat Sci 4:13–18

Ohsawa M (1995) Latitudinal comparison of altitudinal changes onforest structure, leaf-types, and species richness in humidmonsoon Asia. Vegetatio 121:3–10

Oliveira-Filho AT, Curi N, Vilela EA, Carvalho DA (1997) Treespecies distribution along soil catenas in a riverside semidecid-uous forest in the southeastern Brazil. Flora 192:47–64

Peet RK (1981) Forest vegetation of the colourado Front Range.Vegetatio 45:3–75

Takyu M, Aiba SI, Kitayama K (2002) Effects of topography ontropical lower montane forests under different geological con-ditions on Mount Kinabalu, Borneo. Plant Ecol 159:35–49

Tang CQ, Ohsawa M (1997) Zonal transition of evergreen, decid-uous, coniferous forests along the altitudinal gradient on ahumid subtropical mountain, Mt. Emei, Sichuan China. PlantEcol 133:63–78

Tang CQ, Ohsawa M (1999) Altitudinal distribution of evergreenbroadleaved trees and their leaf-size pattern on a humid sub-tropical mountain, Mt. Emei, Sichuan, China. Plant Ecol145:221–233

179

Tang CQ, Ohsawa M (2002a) Tertiary relic deciduous forests on ahumid subtropical mountain, Mt. Emei, Sichuan, China. FoliaGeobot 37:93–106

Tang CQ, Ohsawa M (2002b) Coexistence mechanisms ofevergreen, deciduous and coniferous trees in a mid-montanemixed forest on Mt. Emei, Sichuan, China. Plant Ecol 161:215–230

Wang CW (1961) The forests of China with a survey of grasslandand desert vegetation. Maria Moors Cabot Foundation publi-cation no. 5. Harvard University Press, Cambridge, Mass.

Wang YQ (1987) Nature conservation regions in China. Ambio16:326–331

Ware S, Redfearn PL Jr, Pyrah GL, Weber WR (1992) Soil pH,topography and forest vegetation in the central Ozarks. AmMidl Nat 128:40–52

Webb LJ (1969) Edaphic differentiation of some forest types ineastern Australia. II. Soil chemical factors. J Ecol 57:817–830

Whittaker RH (1978) Classification of plant communities. Junk,The Hague

Whittaker RH, Boul SW, Niering WA, Havens YH (1968) A soiland vegetation pattern in the Santa Catalina Mountains, Ari-zona. Soil Sci 105:440–450

Winkler D (1997) Waldvegetation in der Ostabdachung des tibe-tischen Hochlands und die historische und gegenwartige Ent-waldung. Erdkunde 51:143–163

Wolfe JA (1979) Temperature parameters of humid to mesic forestof East Asia and relation to forests of other regions of theNorthern Hemisphere and Australasia. United States Geolog-ical Survey, professional papers 1106. United States Govern-ment Printing Office, Washington, D.C.

Wu ZY (1983) The vegetation of China (in Chinese). AcademiaSinica, Beijing

Zhao BL, Chen YH (1980) Mount Emei (in Chinese). SichuanPeople’s, Chengdu, China

180