Morphological variations and sex expression in gametophytes of Cibotium barometz under in vitro conditions

Abstract

Abstract. Karyati, Ipor IB, Jusoh I, Wasli ME. 2017. The diameter increment of selected tree species in a secondary tropical forest in Sarawak,. The diameter at breast height (DBH) increments of dominant tree species in a secondary forest can determine forest growth in the area. This study was conducted to investigate the DBH increments of the nine dominant tree species in a secondary tropical forest. A total number of 180 trees representing nine species, seven genera, and six families were selected for the assessment of DBH increments during two years of study. ) had shown a high growth rate during the assessment, while the other four species such as Macaranga gigantea Mull. Arg., Macaranga triloba Mull. Arg., Euodia glabra (Bl.) Bl., and Vitex pubescens Vahl. had 0.53, 0.48, 0.37, and 0.30 cm year -1 in DBH increments, respectively. The average DBH increments for the entire selected species was 0.86 cm year -1 for periodic measurement and 0.75 cm year -1 for monthly measurement. This information is needed in order to understand the succession process in the secondary forests. It is important for the selection of the suitable species in a reforestation and a rehabilitation projects.

Rehabilitation and soil conservation of degraded land using sengon (Falcataria moluccana) and peanut (Arachis hypogaea) agroforestry system

“…Similarly, a study by Wahyudi and Panjaitan (2013) reported that sengon grown on an agroforestry system showed the highest diameter increment (3.45 cm/year) compared with that of the sengon cultivated in an intensive monoculture (3.21 cm/year) and a conventional monoculture system (1.99 cm/year). Interestingly, the diameter increments of sengon obtained in this study were higher than that of predominant trees grown in a secondary tropical forest (0.75-0.86 cm/year) (Karyati et al 2017). In a study on agroforestry system cultivating a combination of sengon and nilam, Sudomo (2007) reported that 18-monthold sengon exhibited a stem diameter and a height of 6.85 cm and 5.59 cm, respectively.…”

Tree stand floristic dynamics in secondary forests of different ages in Sarawak, Malaysia

“…In addition, due to the poor soil fertility status in the area, 50 years of fallow period would be insufficient for the land to recover its vegetation condition, equivalent to that of natural forests (Wasli et al 2011). The tree growth of secondary forest reflects the development during secondary succession process as well as their community structure, composition, and diversity (Karyati et al 2017). Tanaka et al (2007) stated that with increasing length of fallow periods, tree species replace the pioneering small plants, such as grasses, ferns, and shrubs, through vegetation succession.…”

Functional traits partially mediate the effects of chronic anthropogenic disturbance on the growth of a tropical tree

“…However, when individual trees reach the maturity, they invest more in reproduction, maintenance and defence rather than growth ( Coley et al 1985 ; Ryan and Yoder 1997 ; Poorter et al 2008 ). For A. africana , the maximum growth rate was reached at smaller diameter values than reported for other tropical trees ( Bragg 2002 ; Karyati et al 2017 ). For example, in the Amazonian forest, while many canopy species have diameter at maximum growth of 30–50 cm, understory species show lower values ( Hérault et al 2011 ).…”

“…In South-East Asia, widespread species such as Endospermum diadenum , Macaranga gigantean or Cratoxylum spp. expressed their highest growth rates between 15 and 22 cm ( Karyati et al 2017 ). Consistent with the lower than expected diameter of maximum growth rate in A. africana , we also found that the maximum growth was far lower than many other tropical species ( Karyati et al 2017 ).…”