Supplementary Material

Common trees across study area:

Tectonagrandis, Dendrocalamusstrictus, Buteamonosperma, Diospyrosmelanoxylon, Eucalyptus globulus,Madhucaindica, Acacia catechu, Acacia nilotica, Acacia leucophloea, Alangiumsalvifolium, Azadirachtaindica, Bombaxceiba, Boswelliaserrata, Holarrhenaantidysenterica, Prosopisjuliflora, Lagerstroemia parviflora, Mitragynaparvifolia, Wrightiatinctoria, Wrightiatomentosa, Zizyphusjujuba are the common trees found across the study area. Tectona, Dendrocalamus, Prosopis, Madhuca, Acacia spp, Eucalyptus, Mangiferaindica, Azadirachtaindica are the major ones identified and planted widely by the state forest department.

Microbial Biomass Carbon (MBC) estimation:

MBC estimation was done for the replicates (n=3) of collected soil samples by chloroform fumigation extraction method (Witt et al. 2000). In brief, 20 g of dried soil samples were taken in 250 ml Schott bottles. Nearly 10 ml of distilled water was added for moistening and triggering microbial activity. Microbial carbon content was extracted immediately in one set of bottles. To these bottles 0.5 M K2SO4 was added. These were placed on a shaker for an hour. The solution was filtered and carbon content of the filtrate was estimated by wet oxidation method. To another set of bottles 3 ml of ethanol free chloroform was added and sealed. After incubating for 24 hours in darkness, the bottles were opened to evaporate chloroform. 0.5 M K2SO4 was added as mentioned earlier and carbon content was estimated. MBC was calculated as the difference in organic carbon content between fumigated (Cf) and unfumigated soils (Cuf).

MBC (mg kg−1) = Cf−Cuf

Table S1: Tree species across four rainfall zones (RFZs).

Botanical Name / Family Name
Acacia catechuWilld. / Mimosaceae
Acacia leucophloea(Roxb.) Willd. / Mimosaceae
Acacia nilotica(L.) Del. / Mimosaceae
Acacia tortelis(Roxb.) Craib. / Mimosaceae
Adina cordifolia (Roxb.) Bth. & Hk. / Rubiaceae
Aeglemarmelos(L.) Corr. / Rutaceae
Ailanthus excelsaRoxb. / Simaroubaceae
Alangiumsalvifolium (L.f.) Wang / Alangiaceae
AlbiziaamaraBoivin / Mimosaceae
Albiziaodoratissima (L.f.) Bth / Mimosaceae
Albiziaprocera(Roxb.) Bth. / Mimosaceae
AnnonasquamosaL. / Annonaceae
Anogeissuslatifolia (Roxb.) Wall. exBedd. / Combretaceae
AnogeissussericeaBrandis. / Combretaceae
Azadirachtaindica A. Juss. / Meliaceae
Balanitesaegyptiaca(L.) Del. / Balanitaceae
BombaxceibaL. / Bombacaceae
BoswelliaserrataRoxb. / Burseraceae
Brideliaretusa(L.) Spr. / Euphorbiaceae
BuchananialanzanSpr. / Anacardiaceae
Buteamonosperma( Lam.) Taub. / Fabaceae
Buteamonosperma var. lutea (Lam.) Taub. / Papilionaceae
Capparisdeciduas (Forssk.) Edgew. / Capparaceae
CapparissepiariaL. / Capparaceae
CareyaarboreaRoxb. / Lecythidaceae
CaseariagraveolensDalz. / Flacourtiaceae
Cassia auriculataL. / Caesalpiniaceae
Cassia fistula L. / Caesalpiniaceae
Cassineglauca (Rottb.) O. Ktze / Celastraceae
Ceibapentandra (L.) Gaertn. / Bombacaceae
DalbergialanceolariaWilld. / Papilionaceae
DalbergialatifoliaRoxb. / Fabaceae
DalbergiapaniculataRoxb. / Papilionaceae
Dichrostachyacinerea(L.) W. & A. / Mimosaceae
DiospyroscordifoliaRoxb. / Ebenaceae
DiospyrosmelanoxylonRoxb. / Ebenaceae
Eucalyptus globulusLabill. / Myrtaceae
FicusreligiosaL. / Moraceae
Flacourtiaindica (Burm f.) Merr. / Flacourtiaceae
GrewiaflavescensJuss. / Tiliaceae
GrewiatiliaefoliaVahl / Tiliaceae
HardwickiabinataRoxb. / Caesalpiniaceae
HelicteresisoraL. / Sterculiaceae
Holarrhenaantidysenterica(Hyene ex Roth) Wall. / Apocynaceae
Holopteleaintegrifolia(Roxb.) Planch. / Ulmaceae
IxoraarboreaRoxb. Ex Smith. / Rubiaceae
JatrophacurcasL. / Euphorbiaceae
Lagerstroemia lanceolata Wall. / Lythraceae
Lagerstroemia parvifloraRoxb. / Lythraceae
Lanneacoromandelica (Houtt.) Herrill. / Anacardiaceae
Leucaenaleucoephala (Lam) de Wit / Mimosaceae
MadhucaindicaJ. F. Gmel. / Sapotaceae
Manilkarahexandra(Roxb.) Dub. / Sapotaceae
Maytenusemarginata(Willd.) D. Hou. / Celastraceae
Mitragynaparvifolia(Roxb.) Korth. / Rubiaceae
MorindatomentosaHeyne ex Roth. / Rubiaceae
Moringaoliefera Lam. / Moringaceae
Ougeiniaoojeinensis (Roxb) Hochreut. / Fabaceae
ParkinsoniaaculeataL. / Mimosaceae
Pongamiapinnata(L.) Pierre. / Papilionaceae
Prosopisjuliflora (Sw.) DC. / Mimosaceae
PterocarpusmarsupiumRoxb. / Fabaceae
SalvadorapersicaL. / Salvadoraceae
SapindusemarginatusVahl. / Sapindaceae
Schleicheraoleosa(Lour.) Oken. / Sapindaceae
SchreberaswietenioidesRoxb. / Oleaceae
Soymidafebrifuga(Roxb.) A.Juss. / Meliaceae
Tectonagrandis L. f. / Verbenaceae
Terminaliabellirica(Gaerth.) Roxb. / Combretaceae
TerminaliacrenulataRoth. / Combretaceae
WrightiatinctoriaR.Br / Apocynaceae
Wrightiatomentosa R. & S. / Apocynaceae
Zizyphusjujuba Mill. / Rhamanceae
Zizyphusnummularia(Burm. F.) W. & A. / Rhamnaceae
Zizyphusxylopyra (Retz.) Willd. / Rhamnaceae

Table S2: Frequency distribution of trees across the four rainfall zones (RFZs).Frequency classes made according to girth at breast height (GBH, cm) range of trees.

GBH class (cm) / RFZ–1 / RFZ–2 / RFZ–3 / RFZ–4 / All RFZs
10–13 / 59 / 90 / 77 / 206 / 432
14–20 / 310 / 148 / 314 / 352 / 1124
21–30 / 216 / 250 / 417 / 394 / 1277
31–40 / 50 / 221 / 181 / 308 / 760
41–60 / 26 / 134 / 238 / 505 / 903
61–100 / 1 / 54 / 188 / 410 / 653
100 / 0 / 0 / 43 / 132 / 175
Total trees / 662 / 897 / 1458 / 2307 / 5324

Table S3: Mean values of girth at breast height (GBH, cm), density (number of trees ha−1) and diversity (tree species ha−1) of trees across the four rainfall zones (RFZs).

RFZ / Species diversity / Family diversity / Tree density / Mean GBH (cm)
1 / 8 / 5 / 122 / 19.96
2 / 36 / 21 / 135 / 31.68
3 / 38 / 24 / 218 / 38.19
4 / 48 / 29 / 270 / 46.60

Table S4:Regression equationsand correlation values (r) of mean values of the observed parameters with mean annual precipitation (MAP, mm yr−1) across four rainfall zones (RFZs) (n=4, P<0.05).

Parameter / r
value / Regression equation
Species Diversity of trees / 0.77 / y=0.0281x+6.7114, R2=0.59
Family Diversity of trees / 0.77 / y=0.0171x+4.0545, R2=0.60
Density (number of trees ha−1) / 0.93 / y=0.1394x+58.677, R2=0.87
Girth at breast height (GBH, cm) / 0.89 / y=0.0215x+14.378, R2=0.80
Aboveground Biomass (AGB, Mg ha−1) / 0.99 / y = 44.621ln(x) − 282.53, R2=0.98
Soil organic carbon (SOC, Mg ha−1)
up to 25 cm soil depth / 0.93 / y=0.0439x+10.367, R2=0.86
Microbial biomass carbon
(MBC, Mg ha−1) / 0.94 / y=0.0002x+0.1097, R2=0.89

Supplementary Information Figure Captions:

  • Figure S1:Geographical location of Gujarat state (INDIA) showing 22 selected districts(highlighted with yellow colour).
  • Figure S2: Plot outline (250×250 m) and four sub-plots (quadrats) of 0.1 ha (31.62×31.62 m).
  • Figure S3: Relationship between aboveground biomass (AGB) and soil organic carbon (SOC, up to 25 cm soil depth) across four rainfall zones (RFZs), a) RFZ–1 (n=22), b) RFZ–2 (n=31), c) RFZ–3(n=20), and d) RFZ–4 (n=22).
  • Figure S4: Relationship between SOC25(Soil organic carbon, SOC at 25 cm soil depth) and SOC100(SOC at 100 cm soil depth) across four rainfall zones (RFZs) (n=95).
  • Figure S5: Relationship between soil organic carbon (SOC) and microbial biomass carbon (MBC) across four rainfall zones (RFZs) for, a) 0–5 cm soil depth (n=95), and b) 20–25 cm soil depth (n=95).

Figure S1

Figure S2

Figure S3 (a, b, c, d)

Figure S4

Figure S5 (a, b)