Growth rates and crown morphology of Abies amabilis in the seedling bank of an ancient subalpine conifer forest

The population dynamics of shade-tolerant tree species often includes a seedling bank — small trees persisting in the understory until canopy opening allows increased height growth. We studied the growth and morphology of 0.1–1.3 m tall Abies amabilis Douglas ex J. Forbes trees in the seedling bank of an ancient (>1300 years old) subalpine conifer forest on Vancouver Island, western Canada. We determined rates of height growth by counting growth rings at 10 cm intervals along the main stem and assessed crown morphology by measuring the length and location of each branch along the main stem. These small trees were very old (mean basal ring count, 112 years) and grew very slowly, taking on average 170 years to reach a height of 1 m. Instead of the typical conical form of open-grown Abies Mill., seedling bank individuals had flat crowns. Most branches were near the top of the main stem. The maximum distance along the main stem plus a branch was 1.6 times the main stem length, indicating that resource allocation is focused on lateral growth. The ability to grow slowly and adjust crown morphology allows seedling bank trees to persist for decades to centuries and to retain the possibility of release and growth into the canopy.

On the reproductive biology of Salacia fruticosa Wall. ex M.A. Lawson - an endemic medicinal plant of the Western Ghats, india

Salacia fruticosa Wall. ex M.A. Lawson, an endemic species was studied for the reproductive biology as this species showed reduced fruit set and natural regeneration. The stigma-anther proximity, an extremely low number of pollen grains, a short period of pollen viability, a sparse incidence of pollinators, protandrous and facultative autogamous nature of the flowers and a low percent in fruit set were identified as biological constraints for the species. The incidence of seed pest was added to the poor seed and seedling bank and accelerated rarity process of the species.

Keanekaragaman Potensi Regenerasi Vegetasi pada Hutan Rawa Gambut: Studi Kasus di Kawasan Hutan Dengan Tujuan Khusus (KHDTK) Tumbang Nusa, Kalimantan Tengah

Degradasi ekosistem hutan termasuk hutan rawa gambut umumnya diwakili oleh degradasi tutupan vegetasi. Degradasi hutan cenderung mengikuti gradien jarak dari tepi hutan menuju ke dalam hutan. Tujuan dari penelitian adalah untuk mengetahui keanekaragaman dan dominasi potensi regenerasi alami di hutan rawa gambut di Kalimantan Tengah. Anakan alam, guguran buah, dan biji yang tersimpan di lapisan tanah sebagai indikator potensi regenerasi alami diukur dari serangkaian plot terletak mengikuti gradien jarak. Hasil penelitian menunjukkan perbedaan potensi regenerasi alami mengikuti gradien jarak secara signifikan. Keragaman potensi regenerasi alami cenderung menurun mengikuti gradien gangguan, di mana yang terendah ditemukan di tepi hutan. Anakan alam di tepi didominasi oleh Combretocarpus rotundatus (Miq.) Danser sementara Litsea oppositifolia L.S. Gibbs mendominasi di bagian dalam. Guguran buah didominasi oleh Combretocarpus rotundatus di semua gradien jarak pada musim kemarau, sementara itu Palaquium sp. mendominasi gradien dalam hutan dan Combretocarpus rotundatus mendominasi gradien tepi hutan selama musim pancaroba. Hal ini menunjukkan bahwa musim memberi efek signifikan pada jumlah biji, jumlah spesies, dan keanekaragaman guguran buah, dan ketiga indikator potensi regenerasi ternyata lebih tinggi selama musim pancaroba. Biji di lapisan tanah didominasi oleh Tristaniopsis obovata (Benn.) Peter G. Wilson & J.T. Waterh di gradien dalam hutan dan Diospyros sp. di gradien tepi. Namun, biji di lapisan tanah di gradien tepi ini merupakan jenis yang menyusun pada gradien dalam hutan (50% indeks kesamaan). Hal ini menunjukkan bahwa penyebaran benih dari hutan sebagai sumber inokulum masih bisa mencapai tepi dan juga menunjukkan bagaimana kehadiran vegetasi di gradien tepi sebelum terjadi gangguan.Kata kunci: anakan alam; biji di lapisan tanah; gradien jarak; guguran buah; hutan rawa gambut Potential Diversity of Natural Regeneration in Peat Swamp Forest: A Case Study at Forest for Specific Purpose (KHDTK) Tumbang Nusa, Central KalimantanAbstractDegradation of forest ecosystem including peat swamp forest is generally represented by the degradation of its vegetation cover. Forest degradation tends to follow edge-to-interior distance gradient. This study aimed to determine the diversity and dominance of natural regeneration potential in peat swamp forest at Central Kalimantan. Seedling bank, seed rain, and seed soil bank as the indicators of natural regeneration potential were measured from series of plots located following the distance gradient. The results showed that the difference in natural regeneration potentials followed the distance gradient significantly. The diversity of natural regeneration potential tends to decrease following disturbance gradient, where the lowest was found near the edge. Seedling bank at the edge was dominated by Combretocarpus rotundatus (Miq.) Danser while Litsea oppositifolia L.S. Gibbs dominated at the interior. The seed rain was dominated by Combretocarpus rotundatus at all sites during dry season while during intermediate season, Palaquium sp. dominated the interior and Combretocarpus rotundatus near the edge. It was showed that climatic season gave significant effects on seed number, species number, and diversity of seed rain in which all the three regeneration indications were higher during intermediate season. The seed soil bank was dominated by Tristaniopsis obovata (Benn.) Peter G. Wilson & J.T. Waterh near to the interior and by Diospyros sp. at the edge. However, seed soil banks at the edge zone were dominated by species composing the interior forest (50% similarity index). This shows that the seed dispersal from forest as inoculum source can still reach the edge and also indicates existing vegetation at the edge prior to disturbance.

Vegetative propagation through stem cuttings and air layering in Salacia malabarica Gamble, Bull. - an endemic climber of Southern Western Ghats

Salacia malabarica (Celastraceae), an important endemic climber of the southern Western Ghats is found very poor seedling bank in this natural habitats. This will lead to the untimely endangerment of the species in near future. The present study is therefore, aimed to develop and standardize the clonal propagation techniques through stem cuttings and air layering methods with the aid of auxins. The highest rooting of 90% was achieved with the use of NAA-1000 ppm from tender stem cuttings of 10-12 years old plant and air layering success was also found to be 80% by the use of NAA-1000 ppm from the same age of plants used for stem rooting.

Clonal Propagation of Drypetes malabarica (Bedd.) Airy Shaw An Endemic and Endangered Tree of Southern Western Ghats

The juvenile plants of Drypetes malabarica have resulted 100% rooting success for both stem cuttings and air layering by the application of NAA 3000 and IAA 1000 ppm respectively. The rooted plants were also survived with cent percent success rate. Since the tree is being prone to high degree of fruit predation, seed infestation and overall poor natural regeneration in situ restricts, the soil seed and seedling bank and merit extend clonal propagation of the species. The propagation methods thus developed first time could be adopted for the large scale multiplication, establishing clonal gene banks ex situ which in turn ensures the availability of materials for conservation, evaluation and management practices without affecting natural populations of the species in the long run.