Structure and composition of deciduous dipterocarp forest in Central Vietnam: patterns of species dominance and regeneration failure

Abstract

Background: Deciduous dipterocarp forest (DDF) is the most widespread forest type of continental Southeast Asia. Four dominant canopy species of the DDF are often found in near-monodominant stands, but quantitative structure, species composition and regeneration status of these stands are little understood.

Aims: To quantify structural, compositional and regeneration variability of the dominant stands in the DDF at YokDon National Park in Central Vietnam.

Methods: We established seventy 0.04 ha plots across the Park to quantify the structure, species composition and regeneration patterns.

Results: We found distinct patterns of one or two of the four dipterocarp species dominated basal area in any given stand. Patterns of seedling dominance were not as distinct as in the canopy, nor were there strong associations between the dominant seedling and canopy species, particularly for Shorea siamensis. The most striking feature of the forest was the absence of saplings, implying a significant bottleneck in the structure.

Conclusions: Our results suggest a potential shift in the dominant canopy species in the DDF. The apparent lack of recruitment into the larger size classes and the decoupling of dominant species in the canopy and seedling layer raise questions about the future dynamics of the DDF.

Keywords:

• Dipterocarpus tuberculatus
• regeneration bottleneck
• savannah
• Shorea siamensis
• YokDon National Park

Acknowledgements

The authors would like to acknowledge all of the field assistants who contributed to the project: Oanh Bui, Toi Cao, Bon Trinh, Luong Ho, Huy Tran, Jonathan Ho. We thank Stuart Davies for comments on an early draft of the article. Logistical support from the staff of the YokDon National Park and the Vietnamese Academy of Forest Science is greatly appreciated. TTN was supported by an AUSAID Leadership Award and PJB was supported by an Australian Research Council Future Fellowship (FT120100715).

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the AUSAID Leadership Award; Australian Research Council Future Fellowship; [FT120100715].

Notes on contributors

Thuy T. Nguyen

Thuy T. Nguyen performed the fieldwork, analysed the data and wrote the article.

Patrick J. Baker

Patrick J. Bakera provided interpretation of the data analyses and assisted in writing the article.