Composition and structure of mountain forests containing two tropical pines, Pinus krempfii and Pinus dalatensis, on the Da Lat Plateau, southern Vietnam

We examined the floristic composition and stand structure of tropical mountain forests containing two pine species, Pinus krempfii Lecomte and Pinus dalatensis Ferré, on the Da Lat Plateau in southern Vietnam. A total of 92 tree species were identified, and the greatest species richness at the family level was found in Lauraceae and Fagaceae. Both pine species grew to more than 25 m in height and spread their crowns over the continuous canopy layer. Under crowns of P. krempfii, Castanopsis chinensis, Trigonobalanus verticillata, Engelhardia roxburghiana, and Dendropanax hainanensis constituted the continuous canopy layer. Under crowns of P. dalatensis, pioneer species such as Schima wallichii, Exbucklandia populnea, and Pentaphylax euryoides along with gymnosperms such as Dacrycarpus imbricatus and Dacrydium elatum constituted the continuous canopy layer. Juveniles of P. krempfii were prevalent on the forest floor, but juveniles of P. dalatensis were scarce. We suggest that two pine species have different regeneration requirements related to disturbance and soil condition.

Cluster analysis of submontane forest along western slope of Frasers' Hill Research Centre in Raub District, Malaysia

Submontance forest at five different altitudes along the western slope of Frasers' Research Centre (FHRC) in Raub District, Pahang State of Malaysia by Ward Linkage Method (WLM) was classified. Five plots were set at 1000 m (P1), 1050 m (P2), 1100 m (P3), 1150 m (P4) and 1200 m (P5), and all the trees with diameter at breast height (DBH) ≥ 5 cm have been measured. Cluster analysis by WLM of these plots resulted in the identification of four forest zones (FZ) denoted by FZ1P1, FZ2P2, FZ3P3P4 and FZ4P5. These forest zones were denoted by three most dominant species in term of importance value (Iv) such as Dacrydium elatum (Roxb.) Wall. ex Hook.- Prunus arborea (Blume) Kalkman - Adinandra dumosa Jack (Zone FZ1P1), Trigonobalanus verticillata Forman - Syzygium stapfianum (King) I.M. Turner - Syzygium subdecussatum (Wall. ex Duthie) I.M. Turner (Zone FZ2P2), Syzygium leptostemon (Korth.) Merr. & L.M. Perry - Wikstroemia polyantha Merr - Syzygium napiforme (Koord. & Valeton) Merr. & L.M. Perry (Zone FZ3P3P4) and Syzygium filiforme (Wall. ex Duthie) P. Chantaranothai & J. Parn.- Decaspermum parviflorum (Lam.) A.J. Scott - Litsea machilifolia Gamble (Zones FZ4P5). Correlation analysis showed that the number of trees in 0.1 ha, density/ha, DBH, mean DBH, number of species, number of family, number of genus, basal area (BA), mean BA, R, H and E and species with the biggest DBH decreased with increasing altitude. The r-values obtained for these 13 attributes were from – 0.13 to – 0.99. The distribution of trees were found to differ between DBH Class (DBHC) in all FZ. This study revealed that 73.1 to 88.17% of trees in all FZ fall into DBHC1 and DBHC2. On the other hand, 1.02 to 6.28% fall into DBHC5, DBHC6 and DBHC7. The distribution of species was different between Iv Class (IvC) all the four FZ. It was found that from 77.68 to 93.75% of the species fall into IvC1 and IvC2, and between 1.66 to 5.12% of the species fall into IvC4 and IvC5. Key words: Cluster analysis; Submontane forest; Western slope; Malaysia DOI: http://dx.doi.org/10.3329/bjb.v40i2.9767 Bangladesh J. Bot. 40(2): 121-132, 2011 (December)