Impacts of cardamom cultivation on montane forest ecosystems in Sri Lanka

B. Dhakal, M. A. Pinard, I. A. U. N. Gunatilleke, C. V. S. Gunatilleke, H. M. S. P. M. Weerasinghe, A. L. S. Dharmaparakrama, D. F. R. P. Burslem

Research output: Contribution to journalArticlepeer-review

10 Citations (Scopus)


The cultivation of cash crops in the understorey of tropical forests is an ancient practice, but the effects of cultivation on forest ecosystem processes are poorly understood. We assessed the effects of planting the high-value spice crop cardamom (Elettaria cardamomum) on forest structure, tree species composition, and soil properties in the montane forests of the Knuckles Forest Reserve in central Sri Lanka, where cardamom cultivation has been banned since 1985 because of the high conservation value of this site. Vegetation and soil were sampled in forest under-planted with cardamom and adjacent natural forests without planted cardamom. The densities of woody plants (⩾5 cm dbh), saplings (<5 cm dbh and ⩾1.5 m tall), and seedlings (<1.5 m tall) were lower in cardamom plantations than natural forests, while stand basal area was marginally higher in cardamom plantations. Canopy openness at 1.3 m height was higher in the cardamom plantations (mean ± SEM: 35 ± 8%) than in the natural forests (19 ± 3%). Pioneer tree species such as Macaranga sp. increased in abundance in cardamom plantations, and this contributed to the emergence of a difference in species composition between cardamom plantations and adjacent natural forests. Species richness of trees ⩾5 cm dbh per plot was higher in natural forests than cardamom plantations, while species diversity was higher in cardamom plantations. The concentration of total N in top-soil was higher in natural forests, while concentrations of total P and exchangeable K were higher in the cardamom plantations. We conclude that cardamom cultivation results in a net loss of tree stems through weeding and opening of the canopy to promote cardamom production. The higher concentrations of total P and exchangeable K in the soil of cardamom plantations may be associated with the application of fertilizer, while total N concentration may have been higher in the natural forests because residual uncultivated forest occurs at a slightly higher elevation than the majority of cardamom plantations and/or because of elevated denitrification rates in the cardamom plantation. Since cardamom cultivation has affected forest structure and soil properties, management interventions may be required to mitigate these effects in high conservation value forests where cardamom cultivation has been banned.
Original languageEnglish
Pages (from-to)151-160
Number of pages10
JournalForest Ecology and Management
Publication statusPublished - 15 Jun 2012

Bibliographical note

We thank the Darwin Initiative (Project No. 15010) for financial support and the Forest Department of Sri Lanka for granting permission to carry out research in the Knuckles Conservation Area. We are also grateful to the managers of the Midland Estate, Kalebokka Estate and Hare Park Estate for allowing us to carry out research in their cardamom plantations. Our thanks also go out to the Postgraduate Research Institute of the University of Peradeniya for administering the grant and providing office facilities to carry out this research.


  • Knuckles Forest Reserve
  • Montane forest
  • cardamon
  • forest disturbance
  • forest structure
  • conservation


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